Systems and methods for autopilot interface and nudge control

Abstract

The present disclosure relates generally to flight control of aircraft and other powered aerial vehicles. In one embodiment, an aircraft is disclosed, comprising: an autopilot system configured to control the aircraft based on stored flight trajectory information and a flight control system configured to provide a limit to the autopilot system, wherein the limit is based on at least one of: a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft. The autopilot system is configured to determine one or more commands based on the limit received from the flight control system and provide the one or more commands to the flight control system to control the aircraft.

Description

SYSTEMS AND METHODS FOR AUTOPILOT INTERFACE AND NUDGE CONTROLCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 572,146, titled “SYSTEMS AND METHODS FOR AUTOPILOT INTERFACE AND NUDGE CONTROL,” filed March 29, 2024 (Attorney Docket No. 16499.6016-00000) and to U.S. Provisional Application 63 / 690,304, titled, “AUTOPILOT INTERFACE AND COMMUNICATIONS”, filed September 3, 2024 (Attorney Docket No. 16499.6021-00000). The entire contents of the aforementioned applications are incorporated by reference herein for all purposes.TECHNICAL FIELD

[0002] This disclosure relates generally to powered aerial vehicles. More particularly, and without limitation, the present disclosure relates to innovations for controlling aircrafts while in flight (e.g., through flight control systems), including aircrafts driven by electric propulsion systems. Certain aspects of the present disclosure generally relate to systems and methods for flight control of aircrafts driven by electric propulsion systems and in other types of vehicles, as well as flight control of aircrafts in flight simulators and video games.BACKGROUND

[0003] The present disclosure generally relates to a flight control system and an autopilot system. Some aircrafts, such as an eVTOL aircraft, may be capable of operating in multiple different phases (e.g., vertical takeoff, forward flight, vertical landing etc.) and transitioning between phases during flight. A flight control system and autopilot system must have sufficient information in order to safely and effectively control the aircraft. Further, a pilot must be able to easily make corrections to the flight path of an aircraft while maintaining the safety and stability of the aircraft.SUMMARY

[0004] The present disclosure generally relates to a flight control system (e.g., including one or more FCCs), an autopilot system, and a communication interface between the systems. The inventors have recognized several problems that may be associated with flight control ofaircraft, including a tilt-rotor aircraft that uses electrical or hybrid-electric propulsion systems (hereinafter referred to as electric propulsion systems or “EPSs”), which may include at least one engine, at least one rotor, at least one propeller, or any combination thereof. There is a desire for an autopilot system to control some or all functions of aircraft control. However, the inventors here have recognized that a traditional autopilot system will not be able to properly control or keep stable a multi-rotor aircraft (e.g., tilt-rotor aircraft) through different flight phases (e.g., hover, transition, winge-borne flight). A traditional autopilot system will not consider the differences in each phase of flight. For example, a traditional aircraft system is not configured to consider that when the aircraft transitions to hover it may have additional degrees of freedom, that maneuvers in hover are more independent (e.g., roll v. bank), and / or that hover phase includes different limitations to maintain aircraft stability. A traditional autopilot system may be unable to handle the greater variation in aerodynamic characteristics experienced by a multi-rotor aircraft transitioning through different flight phases (e.g., vertical take-off, cruise etc.). A traditional autopilot system may be unable to handle the different types of failures that may be experienced by a multi-rotor aircraft (e.g., reduction in battery state and / or loss of one or more electric propulsion systems). Moreover, traditional autopilot systems are not equipped to navigate aircraft according to some of the dramatic flight paths and maneuvers of which VTOL aircraft are capable, as they instead are built for traditional flight on the wing.

[0005] Additionally, there is a desire to configure the flight control system, autopilot system, and communication interface to reliably communicate relevant information between the flight control system and autopilot system. For example, the communication interface (e.g., wired or wireless) between the flight control system and autopilot system must be resilient to failure. Further, each system must have sufficient information to safely perform its functions. For example, the inventors have recognized that the autopilot system should have sufficient information to ensure commands provided to the flight control system do not cause the aircraft to act in an unsafe and / or unstable manner. Finally, the information must be transmitted at a sufficient frequency for each system to perform its functions in a manner that avoids unsafe lags in an aircraft’s response. For example, information packaging, transmission frequency, and transmission prioritization may be adjusted to ensure both the autopilot system and the flight control system reliably perform their functions at a desired timing without exceeding bandwidth limitations of the aircraft.

[0006] Finally, the inventors have recognized that there is a desire for a pilot to see a waypoint (e.g., a landing area) and / or a flight path on a display and intuitively makecorrections to aircraft control (e.g., a flight path) without fully taking over control from an autopilot system. Further, there is a need for easy-to-use means of accepting these corrections and smoothly controlling the aircraft (e.g., to avoid jerking motion or instability).

[0007] Aspects of this disclosure are directed to solving the above problems, and others. For example, certain aspects of the present disclosure relate to a flight control system and autopilot system that reduce the burden on the pilot and effectively control the aircraft. In some disclosed embodiments, the flight control system may provide information (e.g., one or more limits) to the autopilot system to ensure the autopilot is controlling the aircraft in a safe and stable manner. For example, the flight control system may provide one or more limits based on a state of high voltage distribution, state of an electric engine, or flight phase of the aircraft. The autopilot may control the aircraft (e.g., via control commands to a flight control system) in accordance with the one or more limits.

[0008] Certain aspects of the present disclosure relate to a communication interface between an autopilot system and flight control system that is resistant to failure. In some disclosed embodiments, the flight control system and / or autopilot system may include one or more computer systems (e.g., computers and / or processors) and one or more communication links between the systems (e.g., wired or wireless communication). The flight control system or autopilot system may initiate communication over a different system or communication link upon detecting an issue, thereby increasing resilience of the communication interface.

[0009] Other aspects of the invention relate to a nudge control system that allows a pilot to visualize a waypoint and make corrections to aircraft control without fully taking over control of the aircraft. In some disclosed embodiments, while autopilot is controlling the aircraft, one or more processors may adjust a flight trajectory (e.g., a descent profile) based on a pilot adjustment to a waypoint and the aircraft may be controlled according to the adjusted trajectory.

[0010] For example, one aspect of the present disclosure comprises an aircraft including an autopilot system configured to control the aircraft based on stored flight trajectory information and a flight control system configured to provide a limit to the autopilot system, wherein the limit is based on at least one of: a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft. The autopilot system is configured to determine one or more commands based on the limit received from the flight control system and provide the one or more commands to the flight control system to control the aircraft.

[0011] As another example, one aspect of the present disclosure comprises an aircraft including an autopilot system configured to control the aircraft to travel along a flighttrajectory based on stored flight trajectory information, wherein the stored flight trajectory information includes a descent profile. The aircraft may further include a display configured to display a waypoint at an end of the flight trajectory and one or more processors configured to, while the autopilot system is enabled: control the aircraft according to the stored trajectory information via the autopilot system, receive an input from a pilot input device, determine a change in relative position between the waypoint and the aircraft based on the received input, adjust the flight trajectory based on the determined change in relative position, including adjusting the descent profile, and control the aircraft based on the adjusted flight trajectory.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Fig. 1 shows an exemplary vertical takeoff and landing (VTOL) aircraft, consistent with disclosed embodiments.

[0013] Fig. 2 shows an exemplary VTOL aircraft, consistent with disclosed embodiments.

[0014] Fig. 3 shows an exemplary top plan view of a VTOL aircraft, consistent with disclosed embodiments.

[0015] Fig. 4 shows an exemplary architecture of an electric propulsion system, consistent with disclosed embodiments.

[0016] Fig. 5 shows an exemplary flight control signaling architecture, consistent with disclosed embodiments.

[0017] Figs. 6A, 6B, 6C, 6D, 6E, and 6F illustrate exemplary top plan views of aircraft, consistent with disclosed embodiments.

[0018] Figs. 7A, 7B, and 7C illustrate exemplary autopilot interface architecture, consistent with disclosed embodiments.

[0019] Fig. 7D illustrates a flight control system including nudge control, consistent with disclosed embodiments.

[0020] Fig. 7E illustrates exemplary diagram of combining autopilot and flight control system controls, consistent with the disclosed embodiments.

[0021] Fig. 7F illustrates a diagram of an autopilot system, flight control system, and communication interface, consistent with disclosed embodiments.

[0022] Fig. 7G illustrates a diagram of envelope protection constraints, consistent with disclosed embodiments.

[0023] Figs. 7H-7I illustrate flow charts for modeling aircraft dynamics, consistent with disclosed embodiments.

[0024] Figs. 8A, 8B1, and 8B2 illustrate situations where a flight control system may accept nudge control input, consistent with disclosed embodiments.

[0025] Fig. 8C illustrates an example embodiment where the autopilot system allows an acceleration and deceleration selection, consistent with the disclosed embodiments.

[0026] Figs. 8D, 8E, 8F, and 8G illustrate examples of nudge control, consistent with the disclosed embodiments.

[0027] Fig. 8H illustrates an example of nudge control inputs, consistent with the disclosed embodiments.

[0028] Figs. 81 and 8J illustrate an example of nudge control inputs and aircraft control, consistent with the disclosed embodiments.

[0029] Figs. 8K, 8L, and 8M illustrate examples of pilot inceptors, consistent with the disclosed embodiments.DETAILED DESCRIPTION

[0030] The present disclosure addresses systems, components, and techniques primarily for use in an aircraft. The aircraft may be an aircraft with a pilot, an aircraft without a pilot (e.g., a UAV), a drone, a helicopter, and / or an airplane. An aircraft includes a physical body and one or more components (e.g., a wing, a tail, a propeller) configured to allow the aircraft to fly. In some embodiments, the aircraft is driven by one or more electric propulsion systems (hereinafter referred to as electric propulsion systems or “EPSs”). The aircraft may be fully electric, hybrid, or hydrocarbon fuel powered. For example, in some embodiments, the aircraft is a tilt-rotor aircraft configured for frequent (e.g., over 50 flights per work day), short-duration flights (e.g., less than 100 miles per flight) over, into, and out of densely populated regions. Therefore, there is a need for an autopilot system to effectively control the aircraft through many obstacles (e.g., buildings) and for the pilot to have the ability to correct the autopilot control.

[0031] Disclosed embodiments provide new and improved configurations of aircraft components, some of which are not observed in conventional aircraft, and / or identified design criteria for components that differ from those of conventional aircraft. Such alternate configurations and design criteria, in combination, addressed drawbacks and challenges with conventional components, yielded the embodiments disclosed herein for variousconfigurations and designs of components for an aircraft (e.g., electric aircraft or hybridelectric aircraft) driven by a propulsion system.

[0032] In some embodiments, the aircraft driven by a propulsion system of the present disclosure may be designed to be capable of both vertical and conventional takeoff and landing, with a distributed propulsion system enabling vertical flight, horizontal and lateral flight, and transition (e.g., transitioning between vertical flight and horizontal / forward flight). The aircraft may generate thrust by supplying high voltage electrical power to a plurality of engines of the distributed propulsion system, which may include components to convert the high voltage electrical power into mechanical shaft power to rotate a propeller.

[0033] Embodiments may include an electric engine connected to an onboard electrical power source, which may include a device capable of storing energy such as a battery or capacitor, and may optionally include one or more systems for harnessing or generating electricity such as a fuel powered generator or solar panel array. In some embodiments, the aircraft may comprise a hybrid aircraft using at least one electric-based energy source and at least one fuel-based energy source to power the distributed propulsion system, which may be configured to provide power simultaneously or in or alternating fashion. In some embodiments, the aircraft may be powered by one or more batteries, internal combustion engines (ICE), generators, turbine engines, or ducted fans.

[0034] The engines may be mounted directly to the wing, or mounted to one or more booms attached to the wing. The amount of thrust each engine generates may be governed by a torque command from a Flight Control System (FCS) over a digital communication interface to each engine. Embodiments may include forward engines (and associated propellers) that are capable of altering their orientation, or tilt.

[0035] The engines may rotate the propellers in a clockwise or counterclockwise direction. In some embodiments, the difference in propeller rotation direction may be achieved using the direction of engine rotation. In other embodiments, the engines may all rotate in the same direction, and gearing may be used to achieve different propeller rotation directions.

[0036] In some embodiments, an aircraft may possess quantities of engines in various combinations of forward and aft engine configurations. A forward engine may be considered an engine that is positioned predominantly towards the leading edge of a wing. An aft engine may be considered an engine that is positioned predominantly towards the trailing edge of a wing. For example, an aircraft may possess six forward and six aft engines, five forward and five aft engines, four forward and four aft engines, three forward and three aft engines, twoforward and two aft engines, or any other combination of forward and aft engines, including embodiments where the number of forward engines and aft engines are not equivalent.

[0037] In some embodiments, for a vertical takeoff and landing (VTOL) task, the forward and aft engines may provide vertical thrust during takeoff and landing. During flight phases where the aircraft is moving forward, the forward engines may provide horizontal thrust, while the propellers of the aft engines may be stowed at a fixed position in order to minimize drag. The aft engines may be actively stowed with position monitoring.

[0038] Transition from vertical flight to horizontal flight and vice-versa may be accomplished via the tilt propeller subsystem. The tilt propeller subsystem may redirect thrust between a primarily vertical direction during vertical flight phase (e.g., hover-phase) to a horizontal or near-horizontal direction during a forward-flight cruising phase, based on a tilt of one or more propellers (e.g., determining directionality of one or more propellers). A variable pitch mechanism may change the forward engine’s propeller-hub assembly blade collective angles for operation during phases of flight, such as a hover-phase, transition phase, and cruise-phase. Vertical lift may be thrust in a primarily vertical direction (e.g., during a hover-phase). Horizontal thrust may be thrust in a primarily horizontal direction (e.g., during a cruise-phase).

[0039] In some embodiments, a “phase of flight” or “flight phase” (e.g., hover, cruise, forward flight / winge-borne flight, takeoff, landing, transition) may be defined by a combination flight conditions (e.g., a combination of flight conditions within particular ranges), which may include one or more of an airspeed, ground speed, altitude, pitch angle (e.g., of the aircraft), tilt angle (e.g., of one or more propellers), roll angle, rotation speed (e.g., of one or more propellers), torque value, pilot command, or any other value indicating a current or requested (e.g., commanded) state of at least part of the aircraft. A “flight state” may include a phase of flight and / or forces or environmental factors experienced by the aircraft, such as at least one of weather conditions, air density, natural wind movements, humidity, a proximity of at least one component to a vortex ring state, etc.

[0040] “Vertical flight” or a “hover” phase of flight may be considered any phase of flight where lift for an aircraft is provided predominantly by engines (e.g., EPSs), rather than one or more wings. “Horizontal flight, a “cruise” phase of flight, or a wing-borne phase of flight may be considered any phase of flight where lift for an aircraft is provided predominantly by one or more wings, rather than by any engine (e.g., EPS). “Transition” may be considered any phase of flight where an aircraft is shifting from vertical flight to horizonal flight, or vice versa.

[0041] In some embodiments, in a conventional takeoff and landing (CTOL) task, the forward engines may provide horizontal thrust for wing-borne take-off, cruise, and landing, and the wings may provide vertical lift. In some embodiments, the aft engines may not be used for generating thrust during a CTOL task and the aft propellers may be stowed in place. In other embodiments, the aft engines may be used at reduced power to shorten the length of the CTOL takeoff or landing.

[0042] As detailed above, the aircraft may include multiple electric propulsion systems providing for lift and thrust of the aircraft, and the aircraft may transition through different phases of operation. The aircraft may be an over-actuated aircraft, with multiple solutions available to provide the needed stability and / or control. Traditional autopilot systems may not provide the necessary inputs for control of the aircraft. Further, traditional autopilot systems may not allow a pilot to make corrections without taking over control of the aircraft. The disclosed embodiments provide an autopilot system that effectively controls the aircraft. The disclosed embodiments further allow for pilot corrections to the autopilot control without completely taking over control of the aircraft.

[0043] An “autopilot” may refer to any combination of hardware and software that is able to provide commands to control aircraft functions, including maneuvering functions during flight, without input from a pilot. For example, in some embodiments, an autopilot may generate, store, and / or retrieve trajectories (e.g., positioning, speed, and / or acceleration profiles) and / or waypoints, and transmit commands to autonomously control the aircraft along a trajectory (e.g., a stored, generated, and / or retrieved trajectory). In some embodiments, an autopilot may simply maintain a current state of the aircraft (e.g., hold a climb rate). An autopilot may provide semi-autonomous or fully autonomous flight functionality to an aircraft.

[0044] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise represented. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the disclosure. Instead, they are merely examples of apparatuses and methods consistent with aspects related to the subject matter recited in the appended claims.

[0045] Fig. 1 is an illustration of a perspective view of an exemplary VTOL aircraft, consistent with disclosed embodiments. Fig- 2 is another illustration of a perspective view of an exemplary VTOL aircraft in an alternative configuration, consistent with embodiments ofthe present disclosure. Figs. 1 and 2 illustrate a VTOL aircraft 100, 200 in a cruise configuration and a vertical take-off, landing and hover configuration (also referred to herein as a “lift” configuration), respectively, consistent with embodiments of the present disclosure. Elements corresponding to Figs. 1 and 2 may possess like numerals and refer to similar elements of the aircrafts 100, 200. Aircraft 100, 200 may include fuselage 102, 202, wings 104, 204 mounted to fuselage 102, 202 and one or more rear stabilizers 106, 206 mounted to the rear of fuselage 102, 202. Aircraft 100, 200 may include one or more effectors, which are considered to be any structure capable of influencing flight, such as by manipulating one or more forces to move the aircraft. For example, an effector may include a control surface, an EPS, and / or an actuator (e.g., configured to tilt an EPS or other propulsion device). A plurality of lift propellers 112, 212 may be mounted to wings 104, 204 and may be configured to provide lift for vertical take-off, landing and hover. A plurality of tilt propellers 114, 214 may be mounted to wings 104, 204 and may be tiltable (e.g., configured to tilt or alter orientation) between the lift configuration in which they provide a portion of the lift required for vertical take-off, landing and hovering, as shown in Fig. 2, and the cruise configuration in which they provide forward thrust to aircraft 100 for horizontal flight, as shown in Fig. 1. As used herein, a tilt propeller lift configuration refers to any tilt propeller orientation in which the tilt propeller thrust is providing primarily lift to the aircraft and tilt propeller cruise configuration refers to any tilt propeller orientation in which the tilt propeller thrust is providing primarily forward thrust to the aircraft. While the term “tilt propeller” is used herein, it is appreciated that this term does not necessarily apply to just propellers themselves, but may also include other components of an electric propulsion system of which the propellers are a part, and accordingly may refer to an electric propulsion system that can tilt about an axis (e.g., using an actuator). While the term “lift propeller” is used herein, it is appreciated that this term does not necessarily apply to just propellers themselves, but may also include other components of an electric propulsion system of which the propellers are a part, and accordingly may refer to an electric propulsion system that cannot tilt.

[0046] In some embodiments, lift propellers 112, 212 may be configured for providing lift only, with all horizontal propulsion being provided by the tilt propellers. For example, lift propellers 112, 212 may be configured with fixed positions and may only generate thrust during take-off, landing and hover phases of flight. Meanwhile, tilt propellers 114, 214 may be tilted upward into a lift configuration in which thrust from propellers 114, 214 is directed downward to provide additional lift.

[0047] For forward flight, tilt propellers 114, 214 may tilt from their lift configurations to their cruise configurations. In other words, the orientation of tilt propellers 114, 214 may be varied from an orientation in which the tilt propeller thrust is directed downward (to provide lift during vertical take-off, landing and hover) to an orientation in which the tilt propeller thrust is directed rearward (to provide forward thrust to aircraft 100, 200). The tilt propellers assembly for a particular electric engine may tilt about an axis of rotation defined by a mounting point connecting the boom and the electric engine. When the aircraft 100, 200 is in full forward flight, lift may be provided entirely by wings 104, 204. Meanwhile, in the cruise configuration, lift propellers 112, 212 may be shut off. The blades 120, 220 of lift propellers 112, 212 may be held in low-drag positions for aircraft cruising. In some embodiments, lift propellers 112, 212 may each have two blades 120, 220 that may be locked, for example while the aircraft is cruising, in minimum drag positions in which one blade is directly in front of the other blade as illustrated in Fig. 1. In some embodiments, lift propellers 112, 212 have more than two blades. In some embodiments, tilt propellers 114, 214 may include more blades 116, 216 than lift propellers 112, 212. For example, as illustrated in Figs. 1 and 2, lift propellers 112, 212 may each include, e.g., two blades, whereas and tilt propellers 114, 214 may each include more blades, such as the five blades shown. In some embodiments, each of tilt propellers 114, 214 may have 2 to 5 blades, and possibly more depending on the design considerations and requirements of the aircraft.

[0048] In some embodiments, the aircraft may include a single wing 104, 204 on each side of fuselage 102, 202 (or a single wing that extends across the entire aircraft). At least a portion of lift propellers 112, 212 may be located rearward of wings 104, 204 (e.g., rotation point of propeller is behind a wing from a bird’s eye view) and at least a portion of tilt propellers 114, 214 may be located forward of wings 104, 204 (e.g., rotation point of propeller is in front of a wing from a bird’s eye view). In some embodiments, all of lift propellers 112, 212 may be located rearward of wings 104, 204 and all of tilt propellers 114, 214 may be located forward of wings 104, 204. According to some embodiments, all lift propellers 112, 212 and tilt propellers 114, 214 may be mounted to the wings — i.e., no lift propellers or tilt propellers may be mounted to the fuselage. In some embodiments, lift propellers 112, 212 may be all located rearwardly of wings 104, 204 and tilt propellers 114, 214 may be all located forward of wings 104, 204. According to some embodiments, all lift propellers 112, 212 and tilt propellers 114, 214 may be positioned inwardly of the ends of the wing 104, 204.

[0049] In some embodiments, lift propellers 112, 212 and tilt propellers 114, 214 may be mounted to wings 104, 204 by booms 122, 222. Booms 122, 222 may be mounted beneath wings 104, 204, on top of the wings, and / or may be integrated into the wing profile. In some embodiments, lift propellers 112, 212 and tilt propellers 114, 214 may be mounted directly to wings 104, 204. In some embodiments, one lift propeller 112, 212 and one tilt propeller 114, 214 may be mounted to each boom 122, 222. Lift propeller 112, 212 may be mounted at a rear end of boom 122, 222 and tilt propeller 114, 214 may be mounted at a front end of boom 122, 222. In some embodiments, lift propeller 112, 212 may be mounted in a fixed position on boom 122, 222. In some embodiments, tilt propeller 114, 214 may mounted to a front end of boom 122, 222 via a hinge. Tilt propeller 114, 214 may be mounted to boom 122, 222 such that tilt propeller 114, 214 is aligned with the body of boom 122, 222 when in its cruise configuration, forming a continuous extension of the front end of boom 122, 222 that minimizes drag for forward flight.

[0050] In some embodiments, aircraft 100, 200 may include, e.g., one wing on each side of fuselage 102, 202 or a single wing that extends across the aircraft. According to some embodiments, the at least one wing 104, 204 is a high wing mounted to an upper side of fuselage 102, 202. According to some embodiments, the wings include control surfaces, such as flaps, ailerons, spoilers, and / or flaperons (e.g., configured to perform functions of both flaps and ailerons). According to some embodiments, wings 104, 204 may have a profile that reduces drag during forward flight. In some embodiments, the wing tip profile may be curved and / or tapered to minimize drag.

[0051] In some embodiments, rear stabilizers 106, 206 include control surfaces, such as one or more rudders, one or more elevators, and / or one or more combined rudder-elevators. The wing(s) may have any suitable design for providing lift, directionality, stability, and / or any other characteristic beneficial for aircraft. In some embodiments, the wings have a tapering leading edge.

[0052] In some embodiments, lift propellers 112, 212 or tilt propellers 114, 214 may be canted relative to at least one other lift propeller 112, 212 or tilt propeller 114, 214, where canting refers to a relative orientation of the rotational axis of the lift propeller / tilt propeller about a line that is parallel to the forward-rearward direction, analogous to the roll degree of freedom of the aircraft.

[0053] In some embodiments, one or more lift propellers 112, 212 and / or tilt propellers 114, 214 may canted relative to a cabin of the aircraft, such that the rotational axis of the propeller in a lift configuration is angled away from an axis perpendicular to the top surface of theaircraft. For example, in some embodiments, the aircraft is a flying wing aircraft as shown in Fig. 9E below, and some or all of the propellers are canted away from the cabin.

[0054] Fig. 3 is an illustration of a top plan view of an exemplary VTOL aircraft, consistent with embodiments of the present disclosure. Aircraft 300 shown in the figure is a top plan view of the aircraft 100, 200 shown in Figs. 1 and 2, respectively. As discussed herein, an aircraft 300 may include twelve electric propulsion systems distributed across the aircraft 300, though it is appreciated that an aircraft may include any number of electric propulsion systems, connected at different locations on the aircraft. In some embodiments, a distribution of electric propulsion systems may include six forward electric propulsion systems 314 and six aft electric propulsion systems 312 mounted on booms forward and aft of main wings 304 of aircraft 300. In some embodiments, a length of the rear end of boom 324 from wing 304 to a lift propeller (part of electric propulsion system 312) may comprise a similar rear end of boom 324 length across the numerous rear ends of the booms. In some embodiments, the length of the rear ends of the booms may vary, for example, across the six rear ends of the booms. Further, Fig. 3 depicts an exemplary embodiment of a VTOL aircraft 300 with forward propellers (part of electric propulsion system 314) in a horizontal orientation for horizontal flight and aft propeller blades 320 in a stowed position for a forward phase of flight.

[0055] Aircraft 300 shown in the figure is a top plan view of the aircraft 100, 200 shown in Figs. 1 and 2, respectively. In aircraft 300, control surfaces may include, in addition to the propeller blades discussed earlier, flaperons 712 and ruddervators 714. Flaperons 712 may combine functions of one or more flaps, one or more ailerons, and / or one or more spoilers. Ruddervators 714 may combine functions or one or more rudders and / or one or more elevators. Additionally or alternatively, control surfaces may include separate rudders and elevators. In aircraft 300, the actuators may include, in addition to the electric propulsion systems discussed earlier, control surface actuators (CSAs) associated with flaperons 712 and ruddervators 714, as discussed further below with reference to Fig. 5.

[0056] Fig. 4 illustrates a block diagram of an exemplary architecture and design of an electric propulsion system 400 consistent with disclosed embodiments. Exemplary electric propulsion system (EPS) 400 includes an electric propulsion system 402, which may be configured to control aircraft propellers. Electric propulsion system 402 may include an electric engine subsystem 404 that may supply torque, via a shaft, to a propeller subsystem 406 to produce the thrust of the electric propulsion system 402. Some embodiments may include the electric engine subsystem 404 receiving low voltage direct current (LV DC)power from a Low Voltage System (LVS) 408. In some embodiments, the electric engine subsystem 404 may be configured to receive high voltage (HV) power from a High Voltage Power System (HVPS) 410 comprising at least one battery or other device capable of storing, generating, and / or delivering energy. In some embodiments, electric propulsion system 402 may include one or more energy generation devices, such as a hydrocarb on -fueled turbine or generator, which may provide power to HVPS 410 and / or directly to electric propulsion system 402. HV power may refer to power that is higher in voltage than voltage provided by Low Voltage System (LVS) 408.

[0057] Some embodiments may include an electric propulsion system 402 including an electric engine subsystem 404 receiving signals from and transmitting signals to flight control system 412. In some embodiments, flight control system (FCS) 412 may comprise at least one flight control computer, comprising at least one processor and memory, capable of using Controller Area Network (“CAN”) data bus signals to transmit commands to electric engine subsystem 404 and receive status and data from electric engine subsystem 404. It should be understood that while CAN data bus signals may be used between the flight control computer and the electric engine(s), some embodiments may include alternative forms of communication means enabling transmitting and receiving of data from a flight control computer (“FCC”) to an electric engine. Some embodiments may include electric engine subsystems 404 capable of receiving operating parameters from and communicating operating parameters to an FCC in FCS 412, including speed, voltage, current, torque, temperature, vibration, propeller position, and / or any other value of operating parameters.

[0058] In some embodiments, FCS 412 may also include Tilt Propeller System (“TPS”) 414 capable of transmitting and receiving analog, discrete data to and from electric engine subsystem 404 of tilt propellers (e.g., electric propulsion systems capable of tilting). Tilt propeller system 414 may include apparatus capable of communicating operating parameters to electric engine subsystem 404 and articulating an orientation of propeller subsystem 406 to redirect the thrust of the tilt propellers during various phases of flight using mechanical means such as a gearbox assembly, linear actuators, and any other configuration of components to alter an orientation of propeller subsystem 406. In some embodiments, electric engine subsystem may communicate an orientation of propeller subsystem 406 (e.g., an angle corresponding to, or between, lift and forward thrust) to TPS 414 and / or FCS 412 (e.g., during flight).

[0059] Fig. 5 illustrates a flight control signaling architecture for controlling the control surfaces and associated actuators, according to various embodiments. Although Fig. 5illustrates twelve EPS inverters 501 and associated propeller blades, six tilt propeller actuators (TPACs) 502, six battery management systems (BMSs) 503, four flaperons 504 and associated control surface actuators (CSAs), and six ruddervators 505 and associated CSAs, aircraft according to various embodiments can have any suitable number of these various elements. As shown in Fig. 5, control surfaces and actuators may be controlled by a combination of four flight control computers (FCCs) — Left FCC, Lane A (L FCC-A) 506, Left FCC, Lane B (L FCC-B) 507, Right FCC, Lane A (R FCC-A) 508, and Right FCC, Lane B (R FCC-B) 509, although any other suitable number of FCCs may be utilized. The FCCs may each individually control all control surfaces and actuators or may do so in any combination with each other. In some embodiments, each FCC may include one or more hardware computing processors. In some embodiments, each FCC may utilize a singlethreaded computing process or a multi -threaded computing process to perform the computations required to control the control surfaces and actuators. In some embodiments, all computing process required to control the control surfaces and actuators may be performed on a single computing thread by a single flight control computer.

[0060] The FCCs 506-509 may provide control signals to EPS inverters 501, TPACs 502, BMSs 503, flaperon CSAs 504, and ruddervator CSAs 505, via one or more bus systems. Control signals may be in the form of voltage or current control signals, and control information may be encoded in the control signals in binary, digital, or analog form. In some embodiments, the bus systems may each be a CAN bus system, e.g., Left CAN bus 1 510, Left CAN bus 2 511, Right CAN bus 1 514, Right CAN bus 2 515, Center CAN bus 1 512, Center CAN bus 2 513 (see Fig. 5). In some embodiments, multiple FCCs (e.g., FCCs 506, 507, 508, and / or 509) may be configured to provide control signals via each CAN bus system (CAN Bus 510-515), and each FCC (FCCs 506-509) may be configured to provide control signals via multiple CAN bus systems (CAN Bus 510, 511, 512, 513, 514, and / or 515). In the exemplary architecture illustrated in Fig. 5, for example, L FCC-A 506 may provide control signals via Left CAN bus 1 510 and Right CAN bus 1 514, L FCC-B 507 may provide control signals via Left CAN bus 1 510 and Center CAN bus 1 512, R FCC-A 508 may provide control signals via Center CAN bus 2 513 and Right CAN bus 2 515, and R FCC-B 509 may provide control signals via Left CAN bus 2 511 and Right CAN bus 2 515.

[0061] Figures 6A-6F illustrate exemplary top plan views of aircraft, consistent with disclosed embodiments. There may be several design considerations (cost, weight, size, performance capability etc.) that may influence the number and / or combination of tilt and lift propellers in an aircraft.

[0062] Fig. 6A illustrates an arrangement of electric propulsion systems 601-612, consistent with embodiments of the present disclosure. Referring to Fig. 6A, the aircraft shown in the figure is a top plan view of an exemplary aircraft 650. Aircraft 650 may include twelve electric propulsion systems (601-612) distributed across the aircraft. In some embodiments, a distribution of electric propulsion systems may include six forward electric propulsion systems (601, 602, 603, 604, 605, and 606) and six aft electric propulsion systems (607, 608,609, 610, 611, and 612). In some embodiments, the six forward electric propulsion systems (601, 602, 603, 604, 605, and 606) may be tiltable along at least one axis and may be operatively connected to propellers and the six aft electric propulsion systems (607, 608, 609,610, 611, and 612) may not be tiltable along at least one axis and may be operatively connected to propellers. In other embodiments, the six forward electric propulsion systems (601, 602, 603, 604, 605, and 606) and a number of aft electric propulsion systems (607, 608, 609, 610, 611, and 612) may tiltable along at least one axis and the remaining aft electric propulsion systems may not be tiltable along at least one axis. In other embodiments, all forward electric propulsion systems (601, 602, 603, 604, 605, and 606) and aft electric propulsion systems (607, 608, 609, 610, 611, and 612) may be tiltable along at least one axis . The propellers of an EPS (e.g., propellers described in Figs. 6A-6F) may be tiltable (e.g., the propeller blades may have collective blade tilt), whether or not the EPS itself can tilt. In some embodiments, the tilt of an EPS may be linked with the tilt of propeller blades of the EPS, either through a physical connection or a software command, such that a change increase in tilt of one causes a change of tilt in the other.

[0063] Fig. 6B illustrates an alternate arrangement of electric propulsion systems 613-620, consistent with embodiments of the present disclosure. Referring to Fig. 6B, the aircraft shown in the figure is a top plan view of an exemplary aircraft 651. Aircraft 651 may include eight electric propulsion systems 613-620 distributed across the aircraft. In some embodiments, a distribution of electric propulsion systems may include four forward electric propulsion systems (613, 614, 615, and 616) and four aft electric propulsion systems (617, 618, 619, and 620). In some embodiments, the four forward electric propulsion systems (613, 614, 615, and 616) may be tiltable along at least one axis and may be operatively connected to propellers and the four aft electric propulsion systems (617, 618, 619, and 620) may not be tiltable and may be operatively connected to propellers. In other embodiments, the four forward electric propulsion systems (613, 614, 615, and 616) and a number of aft electric propulsion systems (617, 618, 619, and 620) may be tiltable along at least one axis and may be operatively connected to propellers and the remaining aft electric propulsion systems (617,618, 619, and 620) may not be tiltable and may be operatively connected to propellers. In other embodiments, all forward and aft electric propulsion systems (613-620) may be tiltable along at least one axis and may be operatively coupled to propellers.

[0064] Fig. 6C illustrates an alternate arrangement of electric propulsion systems 638a- 640a, consistent with the embodiments of the present disclosure. Fig. 6C, is a top plan view of an exemplary aircraft 652. In some embodiments, electric propulsion systems 638a-640a may be or include ducted fans that are operably connected to the electric propulsion systems (e.g., electric engines or motors). In some embodiments the aircraft may include one or more banks of ducted fans on each wing of the aircraft (e.g., electric propulsion systems 637a, 638a, 639a, and 640a) on each wing (638, 637, 639, and 640) and each bank of ducted fans may be connected to tilt together (e.g., between lift and forward thrust configuration). In some embodiments aircraft 652 includes a left front wing 638 and right front wing 637 and a left rear wing 639 and right rear wing 640. In some embodiments, each wing (638, 637, 639, and 640) of the aircraft includes a bank of connected ducted fans (e.g., electric propulsion systems 637a, 638a, 639a, 640a). In some embodiments, each bank of connected ducted fans is tiltable (e.g., between lift and forward thrust), while in other embodiments only the bank of fans on the front wing(s) (638a and 637a) are tiltable.

[0065] Fig. 6D illustrates an alternate arrangement of electric propulsion systems, consistent with embodiments of the present disclosure. Referring to Fig. 6D, the aircraft shown in the figure is a top plan view of an exemplary aircraft 653. Aircraft 653 may include six electric propulsion systems (621, 622, 623, 624, 625, and 626) distributed across the aircraft. In some embodiments, a distribution of electric propulsion systems may include a first set of four electric propulsion systems 621, 622, 623, and 624 coplanar in a first plane and a second set of two electric propulsion systems 625 and 626 coplanar in a second plane. In some embodiments, the first set of electric propulsion systems 621, 622, 623, and 624 may be tiltable along at least one axis and may be operatively connected to propellers and second set of electric propulsion systems 625 and 626 may not be tiltable and may be operatively connected to propellers. In other embodiments, the first set of electric propulsion systems 621, 622, 623, and 624 and the second set of aft electric propulsion systems 625 and 626 may all be operatively connected to propellers.

[0066] Fig. 6E illustrates an alternate arrangement of electric propulsion systems, consistent with embodiments of the present disclosure. Referring to Fig. 6E, the aircraft shown in the figure is a top plan view of an exemplary aircraft 654. Aircraft 654 may include four electric propulsion systems distributed across the aircraft. In some embodiments, a distribution ofelectric propulsion systems may include four coplanar electric propulsion systems 627, 628, 629, and 630. In some embodiments, all of the electric propulsion systems (627, 628, 629, and 630) may be tiltable along at least one axis and operatively connected to propellers.

[0067] Fig. 6F illustrates an alternate arrangement of electric propulsion systems, consistent with embodiments of the present disclosure. Referring to Fig. 6F, the aircraft shown in the figure is a top plan view of an exemplary aircraft 655. Aircraft 655 may include six electric propulsion systems 631-636 distributed across the aircraft. For example, in some embodiments, aircraft 655 may include four forward electric propulsion systems 631 632, 633, and 634, which may be tiltable along at least one axis and operatively connected to propellers, and the two aft electric propulsion systems 635 and 636, which may not be tiltable and may be operatively connected to propellers. In some embodiments (not shown), aircraft 655 may include ten electric propulsion systems distributed across the aircraft. For example, in some embodiments, the aircraft may include six forward electric propulsion systems, which may be tiltable along at least one axis and operatively connected to propellers, and the four aft electric propulsion systems, which may not be tiltable and may be operatively connected to propellers. In some embodiments, some or all of the aft electric propulsion systems may operatively connected to tilt propellers.

[0068] As shown in Fig. 6F, in some embodiments, aircraft 655 may have a flying wing configuration, such as a tailless fixed-wing aircraft with no definite fuselage. In some embodiments, aircraft 655 may have a flying wing configuration with the fuselage integrated into the wing. In some embodiments, the tilt propellers may rotate in a plane above the body of the aircraft when the tilt propellers operate in a lift configuration.

[0069] Figs. 7A, 7B, and 7C illustrate exemplary autopilot interface architecture, consistent with the disclosed embodiments. Pilot inceptor(s) 702 may include one or more right inceptor(s) and / or left inceptor(s) (e.g., inceptors 831 and 832, shown in Fig. 8L below). In some embodiments, the right inceptor(s) and / or left inceptor(s) are the inceptors detailed in U.S. Application 18 / 147,640, now U.S. Patent No. 11,702,191, incorporated herein by reference in its entirety and further detailed below with respect to Fig. 8M. In some embodiments, each inceptor (e.g., inceptors 831 and 832, shown in Fig. 8L below) may be configured to move (e.g., pivot) left, right, fore, and / or aft, based on pilot interaction. The position (e.g., angle), direction, and / or rate of movement of the inceptor(s) may generate and / or influence a signal to control the aircraft or at least one component of the aircraft. For example, in some embodiments, inceptor position and / or movement may generate inputs for aircraft models (e.g., dynamics model) and control laws (e.g., implemented) stored in and / oraccessible by control stack 720. In some embodiments, control stack 720 may be or include a software stack, one or more programs, one or more scripts, one or more routines, one or more models, and / or one or more instructions, which may be executed by at least one processor, consistent with disclosed embodiments. Based on the input(s), control stack 720 (e.g., input parsing 704, control loops 705, and / or control allocation 706) may determine roll, yaw, pitch, and / or thrust commands and corresponding control commands 707 (e.g., to electric engines 709 and / or control surface actuators 708). In some embodiments, inceptor position and / or movement may directly generate roll, yaw, pitch, and / or thrust commands and the flight control system may determine corresponding control commands (e.g., to electric engines 709 and / or control surface actuators 708).

[0070] In some embodiments, control stack 720 may be included as part of a flight control system (FCS) 722 of the aircraft. For example, control stack 720 may be included as part of FCS 412, as described above with reference to Fig. 4. In some embodiments, autopilot 703 may be separate from FCS 722 (e.g., may include separate computer(s) and / or processor(s) in wired or wireless communication with FCS 722). Some exemplary aspects of an autopilot, including autopilot 703, are discussed above in paragraph

[0042] , Input parsing 704, control loops 705, and / or control allocation 706 may include one or more modules, functions, models, applications, programs, algorithms, or any executable element configured to carry out one or more of their associated functions, as described herein. For example, input parsing 704, control loops 705, and / or control allocation 706 may include instructions executable by at least one processor to perform one or more of the operations discussed herein.

[0071] In some embodiments, one or more processors (e.g., of control stack 720 and / or FCS 722) may be configured to control the aircraft (or at least one component of the aircraft, such as an actuator or control surface) based on received input from autopilot 703, received sensor data 730, and stored control laws (e.g., stored in or accessible by control stack 720). In some embodiments, the control laws may include one or more control loops (e.g., control loops 705), which may be configured to maintain the stability of the aircraft (e.g., by influencing or controlling one or more aircraft components during flight) based on the received sensor data 730. For example, based on received sensor data 730, control loops 705 may generate commands (e.g., moment commands, such as a rotation force applied to the aircraft) to compensate for disturbances (e.g., based on differences between a commanded and sensed aircraft state). In some embodiments, controlling the aircraft may include combining (e.g., summing, performing a weighted summation, determining a result based on both of) input from autopilot 703 and input from the control laws (e.g., control loops 705). In someembodiments, the input from autopilot 703 may change at, may be determined at, be received at, and / or have changes detected at a faster rate (e.g., frequency, clock speed, computational rate, instruction execution rate, transmission rate) than the input from the control laws. For example, autopilot 703 may transmit output to control stack 720 at a faster frequency than control loops 705 determine control law information. As another example, control stack 720 may receive input from the autopilot 703 at a higher frequency than control stack 720 (or a part thereof, e.g., control loops 705) determines control law information.

[0072] In some embodiments, the same input from pilot inceptor 702 may have a different impact on the aircraft depending on the flight phase and / or flight state. In some embodiments, control stack 720 (e.g., 704, 705, 706) may receive sensor data 730 and determine a flight phase of the aircraft. For example, in some embodiments, control stack 720 may determine, optionally based on an airspeed, propeller speed, and / or tilt angle of the propellers (e.g., as measured by one or more sensors), whether the aircraft is in hover, transition, or forward flight. In some embodiments, the phase of flight may be categorized into more than three phases. Further, in some embodiments, the phase of flight may be continually changing (e.g., as a function of different sensor input). Based on the determined phase of flight, the inceptor 702 position and / or movement may have a different impact. For example, control stack 720 may determine a left or right movement of a first inceptor to indicate a hover-turn when the aircraft is determined to be in a hover phase of flight. Further, control stack 720 may determine the same left or right movement of a first inceptor to indicate a banked turn when the aircraft is in transition or cruise.

[0073] Autopilot 703 may include one or more processors and one or more memory devices. Autopilot 703 may be a device or system that is part of, or distinct from (e.g., separate from) an FCC (e.g., of FCS 412). In some embodiments, autopilot 703 may be configured to generate output (e.g., which may be received as input by one or more processors, such as one or more processors associated with control stack 720 and / or FCS 412) including one or more of at least one simulated pilot inceptor signal, at least one lateral speed, at least one vertical speed, at least one heading rate change, at least one forward speed, at least one forward acceleration, at least one force, or at least one moment.

[0074] In some embodiments, autopilot 703 may receive and / or store information indicative of a flight trajectory to follow (e.g., location(s), position(s), trajectory(ies), path(s), airspeed(s), acceleration(s), phase(s) of flight, flight mode(s), and / or orientation(s)). In some embodiments, autopilot 703 may receive path and / or navigation information (e.g., location of obstacles, terrain, topography, waypoints, target landing locations, etc.) and determine acorresponding trajectory and / or maneuvers (e.g., airspeed, roll rate, yaw rate, descent rate, ascent rate, etc.) based on control loops that consider the aircraft dynamics. The autopilot 703 may store one or more tables, models, and / or equations configured to determine aircraft maneuvers based on navigation, path, and / or trajectory information. In some embodiments, autopilot 703 may further store (or receive, e.g., from FCS 412) kinematic or dynamic constraints, which may correspond to an aircraft flight phase and / or flight state, to limit the determined maneuvers and / or flight path (as further detailed with respect to Fig. 7B below).

[0075] Further, as described above, once a maneuver is determined, autopilot 703 may determine corresponding signal(s) based on one or more maps that relate (e.g., translate, transform, convert, correlate, and / or include in a mathematical relationship that connects) the aircraft maneuver(s) to simulated inceptor input signal(s) that are provided to the control stack. In some embodiments, autopilot 703 may control the entire movement of the aircraft, while in other embodiments autopilot 703 only controls portions of the aircraft movement (e.g., not airspeed).

[0076] Autopilot 703 and / or control stack 720 (e.g., 704, 705, and 706) may receive sensor data 730. For example, autopilot 703 and control stack 720 may receive data from GPS location sensor(s), propeller tilt angle sensor(s) (e.g., magnetic sensor), propeller speed sensors(s), airspeed sensors (e.g., pitot tube sensors), altitude sensor(s), acceleration, orientation sensors (e.g., data from accelerometer(s), 3 -axis accelerometer(s), gyroscope(s), and / or 3-axis gyroscope(s)), and / or one or more inertial measurement units (IMUs). In some embodiments, based on the received sensor data 730, autopilot 703 may detect an error in the aircraft’s response based on exogenous disturbances (e.g., gust causing speed and / or position disturbance) and adjust the aircraft control to follow the trajectory and / or path. In some embodiments, autopilot 703 may determine a flight phase based on the sensor data 730.

[0077] As described above, in some embodiments, autopilot 703 may receive a communication from the flight control system (e.g., a digital communication from an FCS 412) indicating the flight phase of the aircraft. In some embodiments, the flight control system may additionally or alternatively determine and provide one or more limits to autopilot 703. A limit may be expressed as a single value, multiple values, a vector, a matrix, a variable, an equation, a function, or any representation interpretable by at least one processor to limit an operation of an aircraft. The one or more limits may be determined by the flight control system based on or using the flight phase. For example, the limit may comprise at least one airspeed, roll rate, turn rate, climb rate, or descent rate, and the aircraft and the at least one limit may be dependent on the flight phase of the aircraft. In someembodiments, the flight control system may determine and provide minimum and / or maximum values for: airspeed, roll rate, turn rate, climb rate, and / or descent rate to maintain the stability or controllability of the aircraft, optionally based on the determined flight phase. Flight control system 412 may determine these limits dynamically while the aircraft is in flight based on the flight phase, angle of one or more propellers, propeller thrust provided by or commanded to one or more propellers, airspeed, and / or orientation of the aircraft. In some embodiments, flight control system 412 may employ one or more control laws to determine a maximum allowable net moment on the aircraft (e.g., depending on a flight phase and / or aircraft state) which does not cause the aircraft to rotate into an unstable position and may determine one or more limits to avoid exceeding the determined maximum allowable net moment (e.g., to send to autopilot 703). For example, flight control system 412 may employ one or more control laws to determine one or more limits associated with a maximum allowable net moment on the aircraft during takeoff, and may determine one or more different limits associated with a maximum allowable net moment on the aircraft during cruise. As another example, flight control system 412 may determine different values for a maximum climb rate (e.g., to send as a limit to autopilot 703) as the aircraft transitions from hover to wing borne flight. The flight control system may additionally or alternatively provide information on response characteristics of the aircraft, as further described below with reference to Figs. 7H-7I.

[0078] In some embodiments, autopilot 703 and / or control stack 720 (e.g., 704, 705, and 706) may receive data related to the functioning of one or more aircraft flight components. For example, autopilot 703 and / or control stack 720 may receive data (e.g., sensor data 730 and or communications) on the function of one or more electric propulsion systems (e.g., electric engines), such as whether the propellers are operating as commanded (e.g., based on propeller speed feedback), whether temperature of the electric propulsion systems are within an acceptable range (e.g., temperature of engine, control board, and / or wiring within acceptable threshold(s)), whether the propellers are vibrating within an acceptable range, and / or whether a cooling system is operating as intended (e.g., a coolant, such as air or oil, is circulating properly). For example, autopilot 703 and / or control stack 720 may receive information on whether one or more control surfaces, such as one or more ailerons, one or more rudders, one or more elevators, and / or one or more combined rudder-elevators, are operating within an acceptable range (e.g., responding to commands). In some embodiments, one or more limits are transmitted to autopilot 703 based on detecting a state of one or moreaircraft flight components no longer meets a performance threshold (e.g., one or more control surfaces and / or electric engines / electric propulsion systems are not functioning properly).

[0079] In some embodiments, based on this received aircraft component data, FCS 722 may determine one or more limits to provide to autopilot 703. For example, FCS 722 may determine that a lift propeller 112 is malfunctioning (e.g., based on vibrations exceeding a threshold, a temperature of an associated electric propulsion system or wiring exceeding a threshold, and / or any measurable operational characteristic exceeding a threshold), and, based on this determination, the flight control system may provide an indication to autopilot 703 that the aircraft can only be landed in a conventional manner (e.g., can’t perform vertical landing) and / or needs to maintain a certain forward airspeed. The flight control system may additionally or alternatively limit the types of maneuvers the aircraft may perform and / or place limits on aircraft dynamics (e.g., a roll time constant). As another example, the flight control system may transmit limits on the operation of one or more electric motors and / or operation of the overall aircraft (e.g., kinematic or dynamic limits, such as a vertical speed limit) based on the flight control system performing thermal throttling in a hover mode.

[0080] In some embodiments, autopilot 703 and / or FCS 722 (e.g., control stack 720) may receive information on the state of high voltage distribution. For example, autopilot 703 and / or control stack 720 may receive data on a state of switching devices (e.g., open or closed), a state of one or more fuses (e.g., blown or not blown), a temperature of high voltage wiring, and / or a state of a battery packs or associated cells (e.g., battery pack state of temperature (SOT), state of charge (SOC), state of power (SOP), state of energy (SOE), power consumption, capacity, impedance, and / or any other battery pack state). Additionally or alternatively, state estimation may include a weight of the aircraft (e.g., based on load conditions, based on passengers and / or cargo) and / or a center of gravity of the aircraft.

[0081] A state of temperature (SOT) may include or indicate a temperature of at least a portion of a battery cell (e.g., at least one active material of the battery cell, the battery cell itself, multiple battery cells, a battery pack, etc.). For example, an SOT may indicate a core or inner temperature of a battery cell, a temperature of the top of the battery cell, a temperature of the middle of the battery cell, and / or the temperature of the bottom of the battery cell. In some embodiments, an SOT may be based on a measured temperature value (e.g., measured by a temperature sensor adjacent to or on a battery cell). In some embodiments, an SOT may be based on a measured temperature value (e.g., measured by a temperature sensor adjacent to or on a battery cell). An SOT may be estimated using temperature measurements, which may be associated with the at least a portion of a battery cell, such as individual battery cells.For example, an SOT may be estimated using the measured temperature value (e.g., using a model relating an outer measured temperature to an inner temperature).

[0082] As another example, an SOT may be a pack-level temperature based on (e.g., calculated using) multiple battery cell SOTs. In some embodiments, an SOT may be based on a measurement (e.g., direct measurement), an estimation (e.g., based on a direct measurement), or a combination of both. An SOT may be expressed as an absolute value of degrees (e.g., in Fahrenheit, Celsius, or Kelvin) and / or a ratio (e.g., with respect to rated limit, safety limit, etc.). In some embodiments, an SOT may be based on an SOH, as discussed further herein. In some embodiments, an SOT may be used to determine an SOC, as discussed further herein. Measurements used for SOT may be taken at a battery cell level and / or derived from measurements taken for multiple cells, such as pack-level measurements. Additionally or alternatively, the SOT of the battery pack may be equal to a combination (e.g., average, weighted average) of SOT of one or more (e.g., each) battery cells. Additionally, or alternatively, SOT of cells in a battery pack may be extrapolated from the SOT of the battery pack. For example, by applying the rationale that SOT of the battery pack estimated using pack-level measurements should be equal approximately the average of SOT of cells in the battery pack, SOT of cells in the battery pack can be estimated.

[0083] An SOC may indicate an ability of at least a battery cell (e.g., the battery cell itself, multiple battery cells, a battery pack, multiple battery packs, etc.) at a particular instant of time to store (or provide) charge. State of charge may be expressed as an absolute number (e.g., Coulombs or Amp-hrs Ah) or as a ratio or percentage relative to a maximum ability of the at least a battery cell to store (or provide) charge. In some embodiments, a state of charge may refer to an available battery pack capacity relative to the battery pack’s rated capacity. Additionally or alternatively, in some embodiments, state of charge may refer to an available battery cell capacity relative to the battery cell’s rated capacity.

[0084] In some embodiments, an SOC may be based on a measured charge or voltage value (e.g., measured by a temperature sensor adjacent to or on a battery cell). An SOC may be estimated using charge or voltage measurements, which may be associated with the at least a portion of a battery cell, such as individual battery cells. Measurements used for SOC may be taken at a battery cell level and / or derived from measurements taken for multiple cells, such as pack-level measurements. Further, in some embodiments, a state of charge of a battery pack may be based on one or more states of charge of one or more battery cells. For example, a battery pack SOC may be a combination (e.g., summation, weighted summation) of each battery cell SOC. Additionally or alternatively, the SOC of the battery pack may be equal to acombination (e.g., average, weighted average) of states of charge of one or more (e.g., each) battery cells. Additionally, or alternatively, SOC of cells in a battery pack may be extrapolated from the SOC of the battery pack. For example, by applying the rationale that SOC of the battery pack estimated using pack-level measurements should be equal approximately the average of SOC of cells in the battery pack, SOC of cells in the battery pack can be estimated.

[0085] State of power may indicate an available power that can be provided by the battery pack over a time horizon, e.g., without exceeding at least one system constraint (such as a battery pack voltage constraint, battery cell temperature constraint, HV wiring current carrying constraint, etc.). SOP may be expressed as an absolute number (e.g., kW, W) or as a ratio or percentage relative to a maximum rated power (e.g., a maximum rated system power).

[0086] In some embodiments, an SOP may be based on a measured charge, temperature, voltage, power, impedance, and / or other value(s) of battery cell characteristic (physical, electrical, and / or chemical) (e.g., measured by a sensor adjacent to or on a battery cell, such as a voltage sensor). An SOP may be estimated using charge or voltage measurements, which may be associated with the at least a portion of a battery cell, such as individual battery cells. Measurements used for SOP may be taken at a battery cell level and / or derived from measurements taken for multiple cells, such as pack-level measurements. Further, in some embodiments, an SOP of a battery pack may be based on one or more SOPs of one or more battery cells. For example, a battery pack SOP may be a combination (e.g., summation, weighted summation) of each battery cell SOP. Additionally or alternatively, the SOP of the battery pack may be equal to a combination (e.g., average, weighted average) of states of charge of one or more (e.g., each) battery cells. Additionally, or alternatively, SOP of cells in a battery pack may be extrapolated from the SOP of the battery pack. For example, by applying the rationale that SOP of the battery pack estimated using pack-level measurements should be equal approximately the average of SOP of cells in the battery pack, SOC of cells in the battery pack can be estimated.

[0087] A state of energy (SOE) may indicate a predicted amount of energy remaining in at least one battery cell (e.g., a single battery cell, multiple battery cells, a battery pack, multiple battery packs, etc.) at a particular time. In some embodiments, an SOE may be based on (e.g., calculated using) an expected future power demand from the at least one battery cell (e.g., demanded by a system, such as a vehicle or aircraft). Additionally or alternatively, an SOE may include or may be based on one or more of an estimated range (e.g., flight range of anaircraft), an amount of useful energy, or an amount of usable energy. In some embodiments, a state of energy may be based on past use of the at least one battery cell (e.g., based on past flights). Additionally or alternatively, an SOE may include or be based on a total energy in a cell, which may be calculated by determining an area under an open circuit voltage-SOC curve. Additionally or alternatively, an SOE may include or be based on the expression of Vnom * Q, where the Vnom is the nominal voltage of a cell or battery, and Q is a charge capacity (e.g., expressed in Ah). In some embodiments, an SOE may include available discharge energy in a battery cell such that when an assumed power demand is realized, a system constraint is reached at the conclusion of the demand. For example, a system constraint may include a minimum cell voltage, a maximum cell temperature, and / or a minimum voltage of one or more connected loads (e.g., EPU). In some embodiments, an SOE may be based on a measured charge, temperature, voltage, impedance, and / or other value(s) of battery cell characteristic (physical, electrical, and / or chemical) (e.g., measured by a sensor adjacent to or on a battery cell, such as a voltage sensor). An SOE may be estimated using charge, temperature, and / or voltage measurements, which may be associated with the at least a portion of a battery cell, such as individual battery cells. Measurements used for SOE may be taken at a battery cell level and / or derived from measurements taken for multiple cells, such as pack-level measurements. Additionally or alternatively, the SOE of the battery pack may be equal to a combination (e.g., average, weighted average) of states of energy of one or more (e.g., each) battery cells. Additionally, or alternatively, SOE of cells in a battery pack may be extrapolated from the SOE of the battery pack. For example, by applying the rationale that SOE of the battery pack estimated using pack-level measurements should be equal approximately the average of SOE of cells in the battery pack, SOE of cells in the battery pack can be estimated.

[0088] In some embodiments, based on this received high voltage distribution data, FCS 722 may determine one or more limits to provide to autopilot 703. For example, the flight control system may determine that a battery pack as a fuse blown or that a battery state is below a certain threshold level. Based on this determination, the flight control system may provide an indication to autopilot 703 that the aircraft can’t generate enough thrust for hover and / or provide limitations on certain maneuvers or aircraft dynamics. In some embodiments, one or more limits are transmitted to autopilot 703 based on detecting a state of high voltage distribution no longer meets a performance threshold (e.g., battery state is below a threshold, battery temperature exceeds a threshold etc.).

[0089] In some embodiments, autopilot 703 and / or FCS 722 may determine one or more constraints (limits) associated with a task associated with the aircraft. In different situations, an aircraft may be given a task, such as a delivery task, flight path task, loitering task, land- and-takeoff task, or any task for moving between locations and / or retrieving and / or delivering a payload. Constraints associated with a task for the aircraft may be transmitted to the aircraft from a ground source and / or from a cockpit input device of the aircraft. In some embodiments, autopilot 703 may store (and / or receive, e.g., from FCS 722) information on different aircraft orientations, configurations, and / or phases of flight to maintain along different parts of a trajectory, which may be based on received task information. For example, in some embodiments, autopilot 703 may store and / or receive a constraint associated with a roll angle, pitch angle, airspeed, ascent rate, descent rate, and / or yaw angle to maintain in order to accommodate a constraint of the task for the aircraft. For example, a task may include a parameter or constraint related to a payload carried by the aircraft (e.g., a fire hose, camera, package, etc.), such as a target pitch angle for carrying the payload over a designated area. In some embodiments, the constraint (limit) may be expressed as an absolute value, as a minimum value or a maximum value (e.g., a minimum pitch angle to maintain), while in other embodiments the constraint may be expressed as a relative value (e.g., a pitch angle relative to a current pitch angle). In some embodiments, a constraint (e.g., limit) may include a tolerance range (e.g., maintain a pitch angle of 10 degrees + / - 2 degrees, maintain a pitch angle of at least 8 degrees, etc.).

[0090] As another example, a task may include a constraint (e.g., limit) related to a maneuver to be performed by the aircraft, such as a pitch angle for performing a flare maneuver at landing (e.g., to accommodate a short runway), a roll angle to perform a slip descent, a target speed and / or pitch angle for landing on water, a target speed, roll angle, and / or pitch angle for landing on a sloped surface, etc. In some embodiments, the constraint may vary along a trajectory of the aircraft (e.g., a different roll angle or pitch angle may be required at different points). In some embodiments, autopilot 703 may determine a constraint (e.g., limit) and / or commands (e.g., to send to FCS 722) based on sensor information (e.g., lidar, radar, and / or camera information). For example, autopilot 703 may determine a pitch angle that accommodates an aircraft landing on sloping terrain (e.g., a boat or hill).

[0091] In some embodiments, the task and / or associated constraints (e.g., limits) may include prioritization information. In some embodiments, prioritization information may include a discrete ranking (e.g., High, Med, Low), while in other embodiments prioritization information may include a continuous range (e.g., 1 (lowest) -100 (highest)). For example, insome embodiments, autopilot 703 may receive and / or determine a prioritization that prioritizes at least one flight parameter over another. For example, autopilot 703 may receive and / or determine a prioritization that prioritizes maintaining a target pitch angle (e.g., to accommodate a payload) over maintaining a target vertical speed. Therefore, when maintaining both a target pitch parameter and vertical speed is not possible, autopilot 703 will command the aircraft (e.g., via commands to FCS 722) to operate according to the pitch angle constraint and may exceed a target vertical speed (and / or vertical speed range).

[0092] In some embodiments, the task and / or associated constraints (e.g., limits) may include envelope protection information indicating a level of envelope protection that is required. For example, control stack 720 (e.g., control loops 705) and / or autopilot 703 may use more conservative envelope protection limits as a default and may adjust those limits based on task and / or parameter information indicating different envelope protection limits should be used for part or all of an aircraft trajectory (e.g., to accommodate a more aggressive maneuver, such as slip descent or stall as part of a flare maneuver). In some embodiments, FCS 722 and / or autopilot 703 may store multiple sets of envelope protection limits (e.g., maneuvers and / or orientations associated with conservative, medium, and / or aggressive limits) and may retrieve the applicable set of limits based on the task and / or parameter information. In some embodiments, autopilot 703 may provide envelope protection information (e.g., a level, ranking etc.) to control stack 720 to be used in aircraft stabilization. In some embodiments, task information may indicate that envelope protection limits should be relaxed. For example, task information may indicate that the aircraft will perform one or more maneuvers near, at, or beyond a default, normal, or typical control authority limit.

[0093] In some embodiments, FCS 722 and / or autopilot 703 may temporarily suspend an otherwise active set of envelope protection limits, such as based on the task and / or associated parameters. For example, when a particular task applies to only a portion of a flight, FCS 722 and / or autopilot 703 may temporarily suspend an otherwise active set of envelope protection limits during that portion, to allow for performance of the task (e.g., when the active set of envelope protection limits would hinder performance). Temporarily suspending an otherwise active set of envelope protection limits may include using an alternate set of envelope protection limits, consistent with disclosed embodiments.

[0094] The below table 1 provides examples of aircraft orientations and movements and how the limits (e.g., boundaries) of the aircraft orientations and movements may be varied. As further described below with respect to Figs. 7H-7I, in some embodiments these limits may be applied by adjusting (e.g., by FCS 722 and / or autopilot 703) a saturation limit, whichmay define a boundary of an aircraft response, and / or transfer coefficient. The term “limit” and “saturation limit” are used interchangeably throughout this disclosure.Table 1 :

[0095] In the above table 1, “engine availability” may refer to a number of electric propulsion systems that are available and / or may correspond to an amount of thrust that may be imparted by one or more electric propulsion systems. As described above, availability of an electric propulsion system (e.g., electric engine) may vary based on whether the electric propulsion systems are operating as commanded (e.g., based on sensed feedback), temperature of electric propulsion system(s) relative to thermal limit(s), any malfunctions experienced by an electric propulsion system or a system to which it is connected, vibration of components (e.g., propellers), and / or any other sensed data (e.g., sensor data 730) that may impact the capability of one or more electric propulsion systems.

[0096] In the above table 1, “battery state” may refer to one or more of states of a battery described above (e.g., SOT, SOC, SOP, SOE etc.) and / or any other state of the high voltage distribution system that may impact an ability of a battery to provide power to the electric propulsion systems (e.g., state of one or more fuses, temperature of battery pack components relative to thermal limit(s), and / or temperature of wiring relative to thermal limits etc.).

[0097] In some embodiments, autopilot 703 may use the above-described parameters, constraints, or limits to generate a one or more commands to send to flight control system 722 (e.g., commands further described below with respect to Figs. 7a-7c). In some embodiments, autopilot 703 may determine a path or trajectory (e.g., a target trajectory) of the aircraft based on the parameters, constraints, or limits. For example, autopilot 703 may determine whether the aircraft should execute an emergency landing and / or determine trajectories that accommodate one or more operation limits of the aircraft (e.g., determined by flight control system 722). In some embodiments, flight control system 722 may provide information for autopilot 703 to use in path planning. For example, a flight control system may provide information on surrounding terrain (e.g., as determined by lidar, radar, cameras, and / or other sensors). Flight control system 722 may provide autopilot 703 information on aircraft capabilities predicted or estimated for a certain upcoming flight phase or trajectoryand / or based on current operating conditions. For example, flight control system 722 may provide information on upcoming turn rate (e.g., allowing tighter turns) that can be expected in hover flight (e.g., in response to sensing an aircraft is in transition). Flight control system 722 may determine and / or provide any information to autopilot 703 that is part of the flight state of the aircraft. Autopilot 703 may perform trajectory and path planning functions based on these received capabilities and determine one or more commands to control the aircraft (e.g., to be sent to flight control system 722). As another example, flight control system 722 may detect that one or more engines are overheating and begin to throttle the one or more engines. In addition to providing current limits (e.g., kinematic or dynamic limits) as described above, flight control system 722 may provide information on upcoming limits that can be expected if the engine continues to heat up (e.g., at a same or similar rate). Autopilot 703 may perform trajectory and path planning functions based on these received capabilities and determine one or more commands to control the aircraft (e.g., to be sent to flight control system 722).

[0098] In some embodiments, the flight control system may be configured to adjust the frequency at which it transmits data to autopilot 703. For example, as further detailed below, during a transition phase of flight and / or during maneuvers whereby the aircraft operates near a control authority limit, the flight control system may more frequently transmit limits for maneuvers, airspeed, roll rate, turn rate, climb rate, descent rate, and / or kinematic or dynamic constraints. The more frequent transmission of data from the flight control system may help maintain the safety and stability of the aircraft during transition flight where the aircraft’s capabilities are rapidly changing.

[0099] Switch 701 may include one or more means to switch the aircraft control between pilot inceptor(s) 702 and autopilot system 703. For example, switch 701 may include a physical switch (e.g., an inceptor switch), button (e.g., an automatic deceleration button), lever, and / or user interface element (e.g., on a cockpit display). Switch 701 may be configured to switch inputs for aircraft control between manual control by the pilot (e.g., pilot inceptors 702) and autopilot system 703. Alternatively, switch 701 may be configured to blend or combine inputs for aircraft control from manual control by the pilot (e.g., pilot inceptors 702) and autopilot system 703. Switch 701 may be configured to receive manual input from a pilot and adjust the input source (e.g., inceptors 702 or autopilot 703) to input parsing 704 based on the received manual input. Additionally or alternatively, the switch 701 may include at least one processor and / or software that determines to switch between pilot inceptor(s) 702 and autopilot 703 based on a flight condition (e.g., location, speed, position,trajectory, battery status, and / or sensed information) of the aircraft. For example, switch 701 may determine the aircraft is within a threshold distance of the destination (e.g., based on GPS signal), within a threshold altitude of the destination (e.g., based on altitude sensor measurements), and / or in a final flight phase (e.g., hover) and switch to autopilot 703 to control landing. For example, switch 701 may determine an emergency condition, such as aircraft battery level dropping below a threshold (e.g., based on a battery sensor), loss of sensor(s) critical to the autopilot system, erratic behavior (e.g., nose dive), and / or a non- responsive pilot (e.g., based on pilot not responding to warnings) and switch to autopilot 703 to control the aircraft. In some embodiments, switch 701 may permit input from both inceptors 702 and autopilot 703 to influence control stack 720. For example, switch 701 may be activated to cause autopilot 703 to have primary control over control stack 720, but may permit inceptors 702 to provide secondary input (e.g., input summed with autopilot input, input that modifies autopilot input) and / or permit inceptors 702 to override (e.g., deactivate) autopilot 703.

[0100] In some embodiments, switch 701 may confirm certain flight conditions are met prior to allowing a switch between autopilot 703 and pilot inceptor(s) 702 (e.g., may use the flight conditions as a precondition for allowing the switch). For example, a pilot may arm autopilot 703 on ground so that when certain conditions are satisfied (e.g., altitude and / or airspeed), switch 701 determines autopilot 703 will take over.

[0101] Fig. 7A illustrates a first autopilot interface architecture 740, consistent with the disclosed embodiments. As shown in Fig. 7a, input from inceptor(s) 702 and / or autopilot 703 may be received at input parsing 704, which may parse the signal(s) and determine inputs to control loops 705. In some embodiments, autopilot 703 stores or receives (e.g., from a flight control system) limits or constraints and considers these limits or constraints (e.g., avoids commands that violates them) when determining commands. In some embodiments, a flight control system may be configured to translate limits or constraints expressed in one format (e.g., forces, moments, lift, and / or drag, etc.) into another format interpretable by autopilot 703 (e.g., thrust, pitch, roll, yaw, speed, and / or acceleration, etc.).

[0102] In some embodiments, autopilot 703 may be configured to simulate commands of pilot inceptor(s) 702 based on map(s), which may include matrice(s), functions(s), table(s), model(s), and / or equation(s). For example, autopilot system 703 may store one or maps that relate (e.g., translate, transform, convert, correlate, and / or include in a mathematical relationship that connects) inceptor signals (e.g., +70% lateral and -30% longitudinal for the right stick) to aircraft maneuvers. Inceptor signals may include one or more of: analogsignals, analog-to-digital (ADV) values representing a scale of inceptor movement, ADV values representing a scale of inceptor position, ADV values representing a scale of inceptor movement rate, and / or other digital signals generated by movement and / or position of inceptor(s) 702. For example, one or more maps may connect a signal corresponding to percent inceptor deflection (e.g., in a certain direction) to a change in aircraft airspeed.

[0103] In some embodiments, autopilot 703 may store different maps corresponding to different phases of flight. For example, autopilot 703 may determine, based on an airspeed, propeller speed, and / or tilt angle of the propellers, whether the aircraft is in hover, transition, or cruise flight. In some embodiments, flight control system (e.g., FCS 412) provides the flight phase to the autopilot 703. In some embodiments, autopilot 703 may store a map that is configured to determine inceptor output (e.g., simulated output) based on the flight phase (e.g., is configured to understand all phases of flight).

[0104] When autopilot 703 determines (or receives an indication) that the aircraft is in a hover phase of flight, it may retrieve a first map that relates (e.g., translates, transforms, converts, correlates, and / or includes in a mathematical relationship connecting) change in hover-turn rate to a simulated inceptor deflection (e.g., a forward / back deflection or left / right deflection). In contrast, when autopilot 703 determines the aircraft is in transition and / or forward flight, autopilot 703 may retrieve a second map that relates a bank angle turn rate to the same inceptor deflection(s). In some embodiments, as further detailed below, based on an upcoming maneuver, autopilot 703 may determine an inceptor signal to provide input parsing 704 by referencing the corresponding map for the current flight phase.

[0105] In some embodiments, when autopilot 703 determines (or receives an indication) that the aircraft is in hover it may retrieve a first map that relates (e.g., translates, transforms, converts, correlates, and / or includes in a mathematical relationship connecting) a change in airspeed to a simulated inceptor deflection and when the aircraft is in forward flight it may retrieve a second map that relates a change in airspeed to a simulated deflector input. The first and second maps may provide different relationships between airspeed and simulated deflector input. For example, when autopilot 703 determines (or receives an indication) that the aircraft is in hover, autopilot 703 may simulate a signal corresponding to an inceptor position of 50% forward to increase a forward speed by 5m / sA2 (e.g., the aircraft would fly 5m / s faster after 1 second in this position). In some embodiments, when autopilot 703 determines (or receives an indication) that the aircraft is in forward flight, autopilot 703 may simulate a signal corresponding to an inceptor position of 25% to increase a forward speed by 5m / sA2. As another example, when autopilot 703 determines (or receives an indication) theaircraft is in hover, it may retrieve a first map that relates a change in inertial speed to a simulated inceptor deflection and when the aircraft is in forward flight (e.g., CTOL), autopilot 703 may retrieve a second map that relates a change in airspeed rate of change to a simulated inceptor deflection. Fig. 8M provides additional details on the types of mapping that may be provided based on flight phase of the aircraft.

[0106] Control loops 705 may determine and provide corresponding commands (e.g., force and / or moment command(s)) to control allocation 706. Control loops 705 may include model(s) and / or control law(s) to ensure the aircraft responds to the input (e.g., from pilot inceptor(s) 702 and / or autopilot 703) while adhering to one or more parameters, limits, and / or constraints (e.g., in a safe manner), which may be defined by envelope protection. In some embodiments, control loops 705 may include models configured to determine the shape of an aircraft response (e.g., orientation, heading, and propulsion) based on the received input. In some embodiments, control loops 705 may be configured to determine control commands 707 (and / or intermediate commands) based on dynamic models. Dynamic models may provide the control commands required to achieve an aircraft response based on flight phase and / or flight characteristics (e.g., drag, orientation etc.). In some embodiments, control loops 705 may reference different dynamic models based on the aircraft’s flight phase (e.g., whether the aircraft is in hover, transition, cruise etc.). In other embodiments, a single dynamic model may apply to all flight phases.

[0107] Control allocation 706 may control the aircraft based on commands from the control loops 705. For example, control allocation 706 may determine aircraft control commands 707 to achieve one or more primary objectives, such as meeting commanded aircraft forces and moments, and one or more secondary objectives, which can include minimizing acoustic noise and / or optimizing battery pack usage.

[0108] Aircraft control commands 707 may be transmitted to one or more control surface actuators 708 (e.g., corresponding to control surfaces 712 and 714 shown in Fig. 3), including flaperon(s), ruddervator(s), aileron(s), spoiler(s), rudder(s), and / or elevator(s). Further, aircraft control commands 707 may be transmitted to one or more electric engines 709 to control propeller speed and / or a tilt angle of electric engines.

[0109] In some embodiments, the interface configuration of Fig. 7A, including receiving autopilot input from autopilot 703 at input parsing 704, provides the advantage of requiring minimal changes to the control stack. As described above, autopilot 703 may be configured to simulate commands of pilot inceptor(s) 702. Therefore, the control stack may behave in the same or similar manner regardless of whether input is received from inceptors 702 orautopilot 703. For example, control loops 705 and control allocation 706 may function in the same manner to maintain the safety and stability of the aircraft (e.g., prevent aircraft from being controlled to an unsafe state, such as a state represented by at least one value that is outside of a threshold safety range) regardless of input source. Further, this interface configuration may allow easier upgrades to the control stack. For example, adjustments to inputs (e.g., sensor inputs), algorithms, mapping, priorities, constraints, and / or other control variables may be made without needing to consider whether input is from inceptors 702 or autopilot 703.

[0110] Fig. 7B illustrates another autopilot interface architecture 750, consistent with the disclosed embodiments. As in Fig. 7A, control stack 720 may include input parsing 704, control loops 705, and control allocation 706. Control stack 720 may generate control commands 707 and transmit them to control actuators 708 and electric engines 709. In some embodiments, in addition to, or instead of, receiving autopilot inputs at input parsing 704, control stack 720 may receive autopilot inputs at control loops 705. In some embodiments, the type of inputs autopilot 703 provides to control loops 705 may vary based on a flight phase of the aircraft. For example, autopilot 703 may generate commands for achieving forward speed, vertical speed, horizontal speed (e.g., lateral speed), and / or yaw rate (e.g., heading rate change) in a hover flight phase (e.g., for inputting to control loops 705) that different from commands it is configured to generate for achieving forward speed, vertical speed, horizontal speed (e.g., lateral speed), and / or yaw rate (e.g., heading rate change) in a transition flight phase or in a forward flight phase (e.g., winge-bor. For example, autopilot 703 may generate one or more commands that are transmitted to an aircraft effector either directly or indirectly (e.g., first to an FCC, allocation loop, control loop, etc.). Further, autopilot 703 may generate commands for achieving forward acceleration, slideslip rate, pitch rate, and roll rate in cruise (e.g., for inputting to control loops 705). In some embodiments, autopilot 703 selects these commands based on stored or received (e.g., from a flight control system) limits or constraints.

[0111] In some embodiments, autopilot 703 generates, receives, and / or stores flight trajectory, path, and / or navigation information (as described above) and determines corresponding maneuvers (e.g., bank angle etc.) based on internal control loops that use aircraft dynamics (e.g., orientation, phase of flight, flight state, etc.) as a parameter (e.g., constraint, limit). In some embodiments, the determined maneuvers may be adjusted to a format used by control loops 705 (e.g., through additional input parsing).

[0112] Autopilot 703 may receive (e.g., from a flight control system) and / or retrieve one or more kinematic or dynamic constraints that vary based on a determined phase of flight and / or flight state. For example, in a cruise flight phase, the aircraft may have a more constrained turning rate than in hover. Therefore, when determining corresponding maneuvers (e.g., based on a flight path), autopilot 703 may reference the kinematic or dynamic constraints corresponding to the determined phase of flight. Further, autopilot 703 may adjust a path for the aircraft based on the kinematic or dynamic constraints. For example, autopilot 703 may adjust a path to lessen its curvature, based on limits to an aircraft’s turn rate. In some embodiments, autopilot 703 may include and / or be configured to access maps, functions, equations, look-up model(s) and / or table(s) to determine kinematic or dynamic constraints based on the flight phase.

[0113] In some embodiments, the interface configuration of Fig. 7b, including receiving autopilot input from autopilot 703 at control loops 705, provides the advantage of a more seamless interface between semi-autonomous or fully autonomous functions performed by the autopilot 703 (e.g., path and / or maneuver planning) and the control performed by control stack 720. For example, as part of determining autonomous maneuvers, autopilot 703 may determine airspeed (and / or horizontal and vertical speed), acceleration, roll rate, pitch rate, yaw rate, and / or sideslip rate. Autopilot 703 may input these values directly into control stack 720, where they may be used by control loops 705 without the need to convert them into a different form.

[0114] In some embodiments, this configuration provides the added advantage of requiring minimal changes to control stack 720. For example, control loops 705 and control allocation 706 may function in the same manner to maintain the safety and stability of the aircraft (e.g., prevent aircraft from being controlled to an unsafe state) regardless of whether they receive input from autopilot 703 or input parsing 704. Further, this interface configuration may allow easier upgrades to the control stack. For example, adjustments to inputs (e.g., sensor inputs), algorithms, mapping, priorities, constraints, and / or other control variables may be made without needing to consider whether input is from autopilot 703 or input parsing 704.

[0115] In some embodiments, the interface configurations shown in Figs 7A-7B provide the advantage of accommodating processing time that may be required for autonomous decision making. For example, providing input higher up in the control stack may be advantageous because the required input timing is slower than that required at the actuator or engine level.

[0116] Fig. 7C illustrates yet another autopilot interface architecture 760, consistent with the disclosed embodiments. As in Fig. 7A, control stack 720 may include input parsing,control loops, and control allocation. The system may generate control commands 707 to control actuators 708 and electric engines 709. In some embodiments, in addition to, or instead of, receiving input from autopilot 703 at input parsing 704, the system may receive input from autopilot 703 at control allocation 706. For example, autopilot 703 may generate force and / or moment (e.g., rotational force, force and torque) commands, which control allocation 706 may be configured to receive and interpret. In some embodiments, autopilot 703 selects these commands based on stored or received (e.g., from a flight control system) limits or constraints.

[0117] As described above, autopilot 703 may determine, receive, and / or store information associated with (e.g., representing, including, etc.) one or more trajectories, one or more flight paths, and / or navigation information. Autopilot 703 may determine (or receive) maneuvers (e.g., orientation, roll rate, climb rate, acceleration etc.) required along a trajectory and determine corresponding force and / or moment commands to execute these maneuvers. For example, autopilot 703 may store control laws (e.g., control loops) that consider the aircraft dynamics (e.g., orientation, phase of flight, flight state, etc.) and generate force and / or moment commands to execute these maneuvers.

[0118] Similar to the embodiment shown in Fig. 7B, autopilot 703 may receive (e.g., from a flight control system) and / or retrieve one or more limits or constraints to use in determining commands (e.g., force and / or moment commands) for the aircraft. In some embodiments, autopilot 703 may include some or all of control loop 705 functionality (e.g., the ability to control stability of the aircraft based on sensor feedback). In some embodiments, inputs from autopilot 703 and control loop 705 may be combined (e.g., as shown below in Fig. 7E).

[0119] In some embodiments, the exemplary interface configuration depicted in Fig. 7C, which is configured for receiving autopilot input from autopilot 703 at control allocation 706, provides the advantage of allowing autopilot 703 to command more aggressive maneuvers because the input bypasses the control and stability functions performed by control loops 705.

[0120] Fig. 7D illustrates an autopilot interface architecture for nudge control 770, consistent with the disclosed embodiments. As discussed above, switch 701 allows for switching inputs for aircraft control between manual control (e.g., through pilot inceptors 702) and autopilot 703. The autopilot 703 may control the aircraft based on one or more trajectories, one or more flight paths, and / or navigation information. For example, autopilot 703 may reference trajectories including a vertical acceleration profile (e.g., to increase vertical airspeed), a vertical deceleration profile (e.g., to decrease vertical airspeed), a longitudinal acceleration profile (e.g., to increase the aircraft’s airspeed to a set level), and / ora longitudinal deceleration profile (e.g., to decrease the aircraft’s airspeed to a set level or to decelerate to zero for vertical landing).

[0121] In some embodiments, the trajectories may be pre-stored and retrieved, while in other embodiments autopilot 703 may generate one or more trajectories using one or more models and / or equations. For example, autopilot 703 may store one or more equations and / or models configured to calculate a trajectory using a current location, current position, current longitudinal airspeed, longitudinal acceleration / decel eration, vertical airspeed, vertical acceleration / decel eration (e.g., measured from one or more sensors), a preferred waypoint (e.g., a landing location, cruise altitude etc.), flight state, and / or a phase of flight. Autopilot may generate the one or more trajectories based one or more parameters (e.g., task parameters) and / or constraints or limits. These trajectories may be stored as a function of distance or time. In some embodiments, the trajectory will maintain a current heading of the aircraft, while in other embodiments the trajectory may include more complex maneuvers (e.g., roll and / or yaw rates). For example, a pre-stored or generated trajectory may guide the aircraft around a building, other aircraft, flight paths of other aircraft, and / or other obstacle(s). The trajectory may include at least one waypoint along the route. In some embodiments, the waypoint is at an end location the aircraft will reach after following the trajectory. For example, the waypoint may include an altitude and / or lateral location (e.g., latitude and longitude).

[0122] As described above, in some embodiments, autopilot 703 may retrieve aircraft dynamic data and / or sensor data 730 to guide the aircraft along the trajectory. For example, the autopilot system may receive GPS location sensor(s), propeller tilt angle sensor(s) (e.g., magnetic sensor), propeller speed sensors(s), airspeed sensors (e.g., pitot tube sensors), altitude sensor(s), acceleration and / or pitch orientation sensors (e.g., accelerometer(s), 3-axis accelerometer(s), gyroscope(s), and / or 3-axis gyroscope(s)), and / or one or more inertial measurement units (IMUs). In some embodiments, based on the received sensor data 730, autopilot 703 may detect an error in the aircraft’s response based on exogenous disturbances (e.g., gust causing speed and / or position disturbance) and adjust the aircraft control to follow the trajectory.

[0123] In some embodiments, display 710 may display a path of the aircraft (e.g., a path taken when following the trajectory), the waypoint, and / or a GPS error boundary of the path and / or waypoint (e.g., a circle around the waypoint). In some embodiments, while the autopilot 703 is disengaged, the display 710 may continually adjust the path, waypoint, and / or GPS boundary(ies). Therefore, a pilot may be aware of the path and / or waypoint theaircraft will take upon engaging autopilot 703 with switch 701. In some embodiments, once autopilot 703 is engaged, the path and / or waypoint may remain unchanged on the display 710 until receiving a particular input (e.g., a nudge control input).

[0124] In some embodiments, upon switching to autopilot 703, the aircraft will follow the trajectory but will accept one or more nudge control inputs from the pilot. A nudge control input may be any input that is configured to change a path, trajectory, waypoint, ending location, acceleration profile, or any navigation parameter of the aircraft (e.g., without deactivating an autopilot). One or more nudge control inputs may be received on nudge control input device, such as a switch, button, lever, user interface element (e.g., on display 710), and / or the pilot inceptors 702 (fore, aft, left, and / or right movement). In a first embodiment, at least one nudge control input may be transmitted to autopilot 703 and autopilot 703 may adjust the trajectory based on the received nudge control input. For example, the nudge control input may adjust the location of the waypoint (e.g., an ending waypoint), such as by increasing or decreasing the waypoint altitude, moving the waypoint left or right of the aircraft (e.g., by shifting or CW / CCW rotation about the aircraft), and / or bringing the waypoint longitudinally closer to or further from the aircraft. Autopilot 703 may adjust the trajectory to end at the adjusted waypoint location. For example, autopilot 703 may adjust the trajectory based on kinematic or dynamic constraints (as described above with reference to Fig. 7A-7C). In some embodiments, display 710 may receive an updated trajectory, path, acceleration profile, and / or waypoint from autopilot 703 and display the adjusted path and / or waypoint. In some embodiments, autopilot 703 may receive the updated trajectory, path, acceleration profile, and / or waypoint from control stack 720.

[0125] In a second embodiment, nudge control input may be transmitted to control stack 720 (e.g., input parsing 704, control loops 705, and / or control allocation 705) and the control stack may combine the nudge control input with input from autopilot 703. For example, control stack 720 may sum the nudge control input with input from autopilot 703. This second embodiment may include an open-loop autopilot 703 that does not receive dynamic data and / or sensor data 730 to control the aircraft. Alternatively, autopilot 703 may receive communications from control stack 720 indicating a change to be made to the aircraft trajectory. Such a configuration may prevent the autopilot 703 from fighting the nudge control input. In some embodiments, display 710 may receive the updated trajectory, path, and / or waypoint from the control stack and display the adjusted path and / or waypoint.

[0126] In some embodiments, upon adjusting the trajectory, autopilot 703 or flight control system (e.g., control stack 720) may determine different flight phases associated withdifferent points (e.g., different locations and / or time steps) along the adjusted trajectory and determine commands (e.g., airspeed, climb rate etc.) based on the flight phase capabilities, limits, or constraints, as described above.

[0127] In some embodiments, autopilot 703 may be disabled upon the pilot’s input for nudge control exceeding a position and / or movement threshold. In some embodiments, movement of the nudge control input device beyond a threshold distance or angle from a starting position (e.g., a position where no nudge control input is received) will disable autopilot 703. In some embodiments, a rate of movement of the nudge control input device beyond a threshold rate (e.g., through a quick jerking motion) will disable autopilot 703. In some embodiments, sustained movement of the nudge control input device beyond a threshold distance or angle for a threshold period of time will disable autopilot 703. In some embodiments, autopilot 703 is disabled upon the aircraft reaching an ending airspeed (vertical and / or horizontal) and / or position set by the trajectory (e.g., the waypoint). The flight control system may maintain the ending airspeed upon cancelling the autopilot system 703, until contrary direction is received from the pilot (e.g., through inceptors 702).

[0128] In some embodiments, autopilot 703 controls both the aircraft’s airspeed (e.g., by controlling thrust on one or more engines) and positioning (e.g., by controlling one or more control surfaces and / or actuators), while in other embodiments autopilot system 703 may simply take over the aircraft’s airspeed (e.g., vertical and / or forward airspeed) and a pilot may maintain control of the aircraft’s heading. In some embodiments, display 710 may display the aircraft’s flight path and / or waypoint based on a current heading of the aircraft (e.g., a set distance ahead of aircraft based on the acceleration or deceleration profile). The flight path and / or waypoint may be rotated clockwise or counterclockwise about the aircraft based on a change to the aircraft’s heading.

[0129] Fig. 7E illustrates an exemplary diagram 780 of combining autopilot and flight control system controls, consistent with the disclosed embodiments. In some embodiments, such as those depicted in Figs. 7A-7D, the autopilot 703 may generate inputs based on a path, trajectory, and / or sensor feedback. Further, control loops 705 may provide inputs to maintain the stability of the aircraft based on sensor feedback. For example, control loops 705 may generate inputs to compensate for disturbances (e.g., disturbances determined based on sensor feedback). For example, control loops 705 may determine that a roll angle is not expected and / or not aligned with the commanded roll angle and may generate an input to correct the roll. Control loops 705 may generate inputs to stabilize the aircraft at a higher rate than the generation of inputs by autopilot system 703. In some embodiments, control allocation 706may generate control commands 707 based on both inputs (e.g., based on a sum of the inputs as shown in Fig. 7D).

[0130] In some embodiments, the inputs of control loop 705 and autopilot 703 may be weighted by control allocation 706. Therefore, the combination of both inputs may be a weighted sum. In some embodiments, the weighting may change based on the flight phase and / or flight conditions of the aircraft. For example, when there is a risk to aircraft stability (e.g., sensor(s) detect unstable movement and / or positioning), input from control loops 705 may be weighted more heavily.

[0131] In some embodiments, output generated by autopilot 703 is up-sampled (e.g., by flight control system) to accommodate combination with one or more outputs generated by control loops 705. In some embodiments, output generated by autopilot 703 may be saturated to avoid impacts to the stability of the aircraft. In some embodiments, saturation may be triggered based on detecting (e.g., detection by flight control system) that control of the aircraft is becoming unstable. For example, FCS 722 may detect that the magnitude of one or more feedback adjustments (e.g., adjustments required based on comparing commanded vs. sensed positioning of an aircraft component) are above a threshold and / or may detect that a frequency of feedback adjustments is above a threshold. In some embodiments, a notch or bandpass filter may be incorporated (e.g., by the flight control system) to avoid commanding the aircraft over certain frequencies, thereby avoiding impacting the stability of the aircraft. In some embodiments, FCS 722 may also use the saturation and / or filtering techniques described above to ensure that pilot inputs (e.g., from an inceptor 702, such as a nudge input) do not impact the stability of the aircraft.

[0132] Fig. 7F illustrates a diagram 790 of an autopilot system 721, FCS 722, and communication interface 723, consistent with disclosed embodiments. In some embodiments, autopilot 721 may correspond to autopilot 703 shown in Figs. 7A, 7B, 7C, and / or 7D and FCS 722 may include control stack 720 shown in Figs. Figs. 7A, 7B, 7C, and / or 7D. As shown, in some embodiments, the autopilot system 721, including processor(s) and memory devices 721(b), may perform functions, such as flight path management, landing pad clearance, terrain and obstacle avoidance, detect and avoid functions, emergency contingency functions, and / or takeoff and landing functions. In some embodiments, one or more of these functions may be performed in response to the autopilot system 721 detecting flight conditions that trigger performance of these functions. For example, autopilot system 721 may determine (e.g., based on information from sensor(s) 726) that the aircraft is near an obstacle (e.g., based on one or more sensor measurements) and perform obstacle avoidancefunctions. In some embodiments, one or more of these functions may be performed upon receiving an alert and / or relevant information from FCS 722 which determined the relevant flight conditions have occurred (e.g., based on information from sensor(s) 726). In some embodiments, one or more of these functions may be enabled by a pilot (e.g., through a pilot input transmitted directly to autopilot system 721 or indirectly through FCS 722). In some embodiments, one or more of these functions may be repeatedly or continuously performed.

[0133] In some embodiments, based on performing the relevant functions, autopilot 721 will determine and provide forward speed command(s), vertical speed command(s), lateral speed command(s), and / or heading rate of change command(s) to FCS 722. In other embodiments, a different set of commands may be provided based on the level at which autopilot system 721 interface(s) with FCS 722, as described above with respect to Figs. 7A-7C.

[0134] As shown, in some embodiments, FCS 722 (e.g., one or more FCCs), including processor(s) and memory devices 722(b), may perform certain functions, such as envelope protection, state estimation, and control of flight elements (e.g., generating and transmitting commands to effectors, such as electric engines and control surfaces). Envelope protection functions may include any protection required to maintain the safety, stability, and / or controllability of the aircraft based on the aircraft’s constraints. Envelope protection may include functions that ensure (or increase a probability that) an aircraft is controlled according to kinematic constraints, dynamic constraints, or other constraints based on the aircraft’s capabilities (e.g., EPS layout, engine temperature, battery state information, etc.) and / or current flight conditions (e.g., a phase of flight, airspeed, flight state, etc.). In some embodiments, FCS 722 is solely responsible for envelope protection. For example, FCS 722 may adjust and / or override inputs from autopilot system 721 to ensure (or increase a probability that) an aircraft is controlled in accordance with constraints. In some embodiments, FCS 722 may provide envelope protection information to autopilot system 721 to ensure commands provided by autopilot system 721 do not exceed established constraints. For example, FCS 722 may provide a limit for a forward speed command to ensure that autopilot system 721 does not command a forward speed greater than the aircraft is capable of achieving in its current state (e.g., flight conditions and / or current capabilities determined using sensor data 726). In some embodiments, FCS 722 may determine and / or change information (e.g., state information, performance estimation information) it transmits to autopilot system 721 based on (e.g., using) envelope protection information. As shown in diagram 791 of Fig. 7G, further detailed below, the envelope protection constraints 797 provided to autopilot 721 may dynamically vary based on a flight state (e.g., flightconditions). For example, a vertical speed limit may vary based on a forward velocity of the aircraft. Embodiments for maintaining envelope protection using FCS 722 are further detailed below with respect to Figs. 7H-7I.

[0135] Flight control system may include one or more state estimation functions configured to estimate, such as by using one or more state-based equations, a state of the aircraft and / or aircraft components based on information received from sensors 726. State estimation may include any information required by FCS 722 and / or autopilot system 721 to control the aircraft. For example, state estimation may include a position of the aircraft (e.g., a yaw angle, roll angle, pitch angle, and / or any other orientation across one or two axes), velocity of the aircraft, angular rate of the aircraft (e.g., roll, pitch, and / or yaw rate), and / or an acceleration of the aircraft (e.g., longitudinal, lateral and / or vertical acceleration), one or more forces experienced by the aircraft or a component thereof, or any physical characteristic of the aircraft or one of its components. Additionally or alternatively, the state estimation may include a flight phase of the aircraft, such as combination of flight conditions (e.g., a combination of flight conditions within particular ranges), which may include one or more of an airspeed, altitude, pitch angle (e.g., of the aircraft), tilt angle (e.g., of one or more propellers), roll angle, rotation speed (e.g., of a propeller), torque value, pilot command, or any other value indicating a current or requested (e.g., commanded) state of at least part of the aircraft. Flight phases may include one or more of: vertical takeoff, short takeoff, hover, forward flight, wing-borne flight, vertical descent, conventional landing, and / or any other flight movements. Further, state estimation may include a state of one or more aircraft components and / or a high voltage distribution system, as described above with respect to Figs. 7A-7C. For example, a state estimation may include a temperature and / or fault status for one or more electric propulsion systems. For example, a state estimation may include battery state information, such as a state of energy, state of power, state of charge, voltage etc. of battery pack(s) and / or a range estimation for the aircraft, as described above. As described above with respect to Fig. 7A, FCS 722 may use one or more state estimation functions to determine limits for autopilot 721 (e.g., a limit based on a state of high voltage distribution, a state of an electric engine, a flight phase of the aircraft, aircraft state, and / or flight state). For example, a flight control system or autopilot may use an output of one or more state estimation functions, which may include one or more values, to compute a limit.

[0136] Sensors 726 may include a combination of sensors used by autopilot system 721 and / or FCS 722 to control the aircraft. In some embodiments, sensors 726 may provide sensor data 730, described above. For example, sensors may include one or more sensorsconfigured to detect vehicle dynamics, such as acceleration and / or pitch orientation sensors (e.g., accelerometer(s), 3-axis accelerometer(s), gyroscope(s), and / or 3-axis gyroscope(s)) and airspeed sensors (e.g., pitot tube sensors). Vehicle sensors 726 may include an inertial navigation systems (INS) and / or an air data and / or an attitude heading reference systems (ADAHRS). The inertial navigation systems (INS) and / or an air data and attitude heading reference systems (ADAHRS) may include one or more inertial measurement units (IMUs) and corresponding sensors (e.g., accelerometers, gyroscopes, three-axis gyroscopes, and / or three-axis accelerometers). For example, sensors may include an air data system and / or air sensors (e.g., pitot tubes), GPS sensors, tilt angle sensors, accelerometers, and / or gyroscopes to determine a flight phase of the aircraft (e.g., by comparing to predetermined threshold(s)). For example, a flight phase change may be determined when an aircraft airspeed exceeds a threshold and / or when an aircraft airspeed drops below a threshold and propeller tilt angle drops below a threshold. Sensors 726 may include one or more current sensors, voltage sensors, and / or temperature sensors, which may be associated with one or more battery packs, electric propulsion systems, and / or electric wiring of the aircraft. Sensors 726 may also include light-based sensors including LIDAR and / or IR / visible wavelength cameras, as well as radar sensors.

[0137] Interface 723 may be configured to translate and / or transmit information between autopilot system 721 and the FCS 722. For example, interface 723 may include a wired or wireless connection between the between the autopilot system 721 and the FCS 722. For example, in some embodiments, interface 723 may be or include a CAN connection. In alternate embodiments, interface 723 may be based on a particular protocol, such as Wireless CAN, FlexRay, Media-Oriented Systems Transport (MOST), Ethernet, Local Interconnect Network, Message Queuing Telemetry Transport, Data Distribution Service. In some embodiments, autopilot system 721 and FCS 722 may be connected via a wired data bus configured to use the ARINC 429 communication protocol or other ethernet-based communication protocol. The autopilot system 721 and / or FCS 722 may package data (e.g., limits, commands etc.) to conform with the wired data bus capabilities (e.g., bit limits, frequency etc.). For example, autopilot system 721 and / or FCS 722 system may be configured to compress data prior to transmission, such as by concatenating values, abbreviating values, and / or transmitting relative changes to values rather than raw values (including, potentially unchanged raw values). Additionally or alternatively, autopilot system 721 and / or FCS 722 system may be configured to segment different types of data into sequential transmissions. For example, one transmission may be configured to include orrepresent an aircraft state, another transmission may be configured to include or represent a trajectory, another transmission may be configured to include or represent an acceleration profile, etc. In other embodiments, autopilot system 721 and FCS 722 may be connected via a wired ethernet connection. In some embodiments, as detailed in diagram 792, interface 723 may include multiple wired or wireless connections between autopilot system 721 and FCS 722. In some embodiments, autopilot system 721 and / or FCS 722 may determine communication is lost over one connection link (e.g., by detecting an issue with the communication bus and / or determining not communication has been received in a threshold time period) and may start communicating over another communication link. In some embodiments, as shown, interface 723 may include multiple systems (e.g., computers and / or associated processors / memory devices) for autopilot 721 and / or FCS 722 and multiple communication link(s) (e.g., two or more) between the systems. Therefore, there is redundancy in communication between autopilot 721 and FCS 722.

[0138] In some embodiments, autopilot system 721 and / or FCS 722 may include one or more functions to organize and transmit information (e.g., data organizing and transmission 721a and 722a, respectively). For example, in some embodiments, an aircraft state may be transmitted by FCS 722 to autopilot 721 on an established periodic time interval. For example, an aircraft state may be transmitted at a time interval determined to be sufficient to maintain the stability and / or controllability of the aircraft (e.g., as determined by experimentation and / or simulations). In some embodiments, the time interval for determining and / or transmitting aircraft state information may vary based on flight conditions. For example, during a transition phase (e.g., takeoff or landing) aircraft state information may be transmitted more frequently. In some embodiments, FCS 722 may determine saturation limits (e.g., constraints) and / or transfer function coefficients. In some embodiments, saturation limits and / or transfer function coefficients may be determined more frequently in a transition phase of flight. Further, in some embodiments, saturation limits (e.g., constraints) may be determined on demand based on the FCS 722 determining an aircraft and / or aircraft component has reached a pre-determined condition (e.g., a pre-determined battery state(s), aircraft component failure (e.g., EPS failure) etc.). In some embodiments, autopilot system 721 and / or FCS 722 may be configured to package and transmit information to avoid bandwidth limitations. In some embodiments, the information may be encoded in accordance with ARINC 812, ARINC 825, CiA 454, IEC 61851-3, ISO 15765-2, MilCAN, SAE J1939, SAE J2284, ISO 14229, LeisureCAN, CANaerospace, UAVCAN, or other higher-layer protocols.

[0139] Data link 724 may transmit and receive information from autopilot system 721 and / or FCS 722 via any of the wired or wireless manners described above with respect to interface 723. For example, data link 724 may receive information from autopilot system 721 and / or FCS 722 using the ARINC 429 data communication protocol and / or an ethernet communication protocol. In some embodiments, data link 724 may provide for communication between the autopilot system 721 and / or FCS 722 and a ground control station 725 (e.g., via a radio link between data link 724 and ground control station 725). For example, ground control station 725 may include one or more processors, memory devices, input devices, and / or display devices to allow for communication between the aircraft and the ground control station 725. For example, aircraft state information may be transmitted from the aircraft (e.g., via autopilot and / or flight control system) and a user may provide control commands to the aircraft via the ground control station 725. Data may be transmitted to and / or from ground control station 725 using a transponder or other transmission component of the aircraft, and may be formatted according to a protocol such as ADS-B. In some embodiments, an additional data link (not shown) may provide for communication between the autopilot system 721 and / or FCS 722 and a test observation station (e.g., via a radio link to a test observation station, such as a computer and / or one or more processors for performing test flights).

[0140] In some embodiments, ground control station 725 may transmit flight plan updates, modifications, and / or commands to autopilot 721 and / or FCS 722. For example, ground control station 725 may transmit data to incorporate into trajectory and / or path planning functions, such as waypoint adjustment (e.g., landing site adjustment), vector commands to comply with Air Traffic Control (ATC), change in altitude to avoid localized turbulence, aircraft state information (e.g., based on one or more ground sensors, such as radar, lidar, cameras etc.), and / or traffic information (e.g., a location and / or trajectory information of surrounding aircraft and / or a location of surrounding infrastructure). In some embodiments, the FCS 722 may relay voice communications from ATC to personnel on the ground through ground control station 725. In some embodiments, FCS 722 may provide a video feed of the inside of the aircraft to personnel on the ground (e.g., to monitor in case of an emergency).

[0141] Fig. 7G illustrates a diagram of envelope protection constraints and a variation of limits, consistent with disclosed embodiments. Referencing Fig. 7G, each “X” represents a state of the aircraft (forward velocity and downward velocity) after receiving a command to perform a pullup execution (e.g., from pilot via inceptors 702 or autopilot 721). The size of the “X” represents the altitude loss of the aircraft after it performs the pullup execution. Forexample, “X” 799b may represent an altitude loss of 40ft and “X” 799a may represent an altitude loss of Oft.

[0142] As shown, envelope protection limit 797 may dynamically vary based on a flight state (e.g., flight conditions). For example, as shown by the angle of envelope protection limit 797, a downward velocity limit may vary based on a forward velocity of the aircraft. In some embodiments, as the aircraft flies, flight control system 722 may provide these varying downward velocity limits to autopilot 721 based on a detected forward velocity.

[0143] Further, in some embodiments, flight control system 722 may provide a varying altitude drop that can be expected following a pullup execution to autopilot 721 (e.g., as represented by the differing sizes of “Xs”) based on a detected aircraft state (e.g., forward velocity and / or downward velocity, as shown). Therefore, autopilot 721 may use the expected altitude drop in one or more path planning functions. For example, autopilot 721 may generate or adjust a trajectory of the aircraft to ensure that sufficient clearance is provided between the aircraft and any surrounding obstacles following a pull up maneuver.

[0144] Figs. 7H-7I illustrate exemplary flow charts for modeling aircraft dynamics, consistent with disclosed embodiments. As shown in flowchart 781 of Fig. 7H, in some embodiments, autopilot system 721 may include a performance estimation function 742 (e.g., algorithm(s), model(s), lookup tables etc.), which may be configured to determine saturation limits for saturation function 743 and coefficients for a transfer function 744 that models an aircraft’s response according to an aircraft state. Autopilot system 721 may determine an aircraft’s response to initial commands (e.g., initial control commands to fly the aircraft along a stored trajectory) by incorporating saturation limits (e.g., from saturation function 743) into transfer function 744 (including coefficients from performance estimation 742) to limit a response of the aircraft. In some embodiments, autopilot 703 may determine updated commands (e.g., an adjustment to initial commands) based on the determined expected aircraft response and provide them to flight control system 722 to control the aircraft. Therefore, autopilot system 721 may be configured to determine one or more commands (updated commands) based on limits received from flight control system 722 and provide the one or more commands to flight control system 722 to control the aircraft.

[0145] For example, autopilot 721 may command an initial vertical airspeed (e.g., 1,500 ft / min or 7.62 m / s) and performance estimation 742 may determine (and / or receive an indication, such as from a flight control system) that there a vertical airspeed limit is active (e.g., based on an electric propulsion system malfunctioning and limiting aircraft vertical speed capabilities and / or based on a flight phase of the aircraft). Performance estimation 742may determine a saturation limit and transfer function coefficient based on this vertical airspeed limitation. An expected aircraft response may be determined by applying saturation limits (e.g., from saturation function 743) to a transfer function 744 (including coefficients from performance estimation 742). Autopilot 721 may generate (e.g., determine) an updated autopilot vertical speed command (e.g., 1,000 ft / min or 5.08 m / s) based on the expected response. In some embodiments, autopilot 721 may also generate other commands with parameter adjustments (e.g., to flight path, aircraft pitch, aircraft roll, control surface angles, etc.) or include additional parameter adjustments within the updated vertical speed command, to accommodate this change in airspeed capabilities while still navigating the aircraft in accordance with stored (and / or detected) navigation, trajectory, or task information. For example, autopilot 721 may also generate an updated heading rate command based on navigation information indicating an obstacle ahead that will no longer be vertically cleared.

[0146] In some embodiments, autopilot 721 may use model predictive control to generate updated commands in an iterative manner (e.g., through multiple incremental changes). For example, autopilot 721 may generate multiple updated commands until finding one that accommodates the aircraft’s limitations while still navigating the aircraft in accordance with stored (and / or detected) navigation and / or trajectory information.

[0147] In some embodiments, autopilot system 721 may maintain a static model of aircraft dynamics to ensure control commands are within established limits or constraints. In some embodiments, autopilot system 721 may additionally or alternatively include look-up tables, models, functions, and / or algorithms that vary constraints based on an aircraft’s state (e.g., as determined based on experimentation and / or simulated conditions). For example, in some embodiments a vertical speed limit and transfer functions can be tabulated into lookup tables referenced by forward airspeed. The autopilot system 721 may receive a forward airspeed from the FCS 722 (and / or sensor input 726), reference a lookup table based on the received airspeed, and transmit commands in accordance with established constraints provided by the lookup table. Some embodiments may use a Low Order Equivalent System (LOES) model to represent (e.g., model, determine, output) one or more aircraft operations, physics, and / or behaviors. For example, the transfer function may include or be based on a LOES model.

[0148] Equation 1 illustrates a generalized form of a transfer function H(s) -.

[0149] This transfer function H(s) may represent the aircraft’s response to any given command. In some embodiments, a transfer function may be updated (e.g., coefficientsadjusted) based on an aircraft's measured response. In some embodiments, a transfer function may remain unchanged for a set time horizon (e.g., 1 second, 5 seconds, 10-100 second, etc.). In some embodiments, coefficients may be determined periodically or in response to more or more flight phase changes (e.g., from hover to winged flight). For example, in some embodiments, a step change in vertical speed may take longer for an aircraft to achieve while in a hover phase of flight than in wing-borne flight. The coefficients may reflect this difference. While equation 1 provides an example of a continuous transfer function, in other embodiments a state space function may be used to model the aircraft’s response.

[0150] For example, autopilot system 721 may receive the aircraft state estimate(s) (e.g., state estimation function 741 of FCS 722) and determine a corresponding saturation limit (e.g., a constraint) to be applied to the control command based on a static model and / or one or more look-up tables, models, functions, and / or algorithms that vary a saturation limit (e.g., a constraint) based on the aircraft state(s).

[0151] In addition to the above examples, saturation limits and / or transfer function coefficients may also vary based on any of the conditions described above with respect to Figs. 7A-C. For example, different saturation limits may apply based on a flight phase of the aircraft, functioning of one or more aircraft components (e.g., considering responsiveness, temperature, vibration), and / or state of high voltage distribution. Further, saturation limits may be determined based on any one or more of the aircraft state(s) illustrated in the table 1, above.

[0152] Autopilot system 721 may further determine transfer function coefficients based on the aircraft state estimate(s). For example, transfer function 744 may detail how an aircraft responds to a command (e.g., how quickly a bank angle may be achieved). Coefficients of transfer function 744 may adjust transfer function 744 to reflect how an aircraft’s response changes based on changing aircraft state estimate(s). For example, an aircraft may respond more slowly in certain aircraft states (e.g., certain airspeed ranges, flight phases etc.) than in others.

[0153] The saturation limit (e.g., constraint) may be applied to transfer function 744 (e.g., via saturation function 743) to estimate an aircraft response that meets the established limits. For example, in some embodiments, the saturation limit may trim response characteristics that exceed the limit. In other embodiments, the saturation limit may be applied at the same time the aircraft response is determined. For example, the transfer function may incorporate the saturation limits (e.g., constraints) when determining an aircraft response. A transfer function may be integrated over a period of time and minimized according to saturationlimits. For example: Transfer function = / Function (x,v) dt, where x<xmax (first saturation limit) and / or y<ymax (second saturation limit).

[0154] Based on determining an aircraft response that meets the established limits (e.g., constraints), autopilot system 721 may perform one or more functions (e.g., one or more of the functions shown above with respect to Fig. 7F). For example, autopilot 721 may evaluate the aircraft’ s response in order to determine control commands to navigate around an obstacle, perform detect and avoid functions, control take-off and landing etc. For example, in some embodiments, transfer function 744 would typically command an aircraft to a lOOft / m climb to get over an obstacle (e.g., a building). However, FCS 722 may determine one or more limits of the aircraft (e.g., a max climb rate due to a reduced engine performance) and provide the one or more limits to autopilot system 721 to saturate an expected aircraft response to be within the limited capabilities (e.g., a reduced capability, such as 50 ft / min or 0.254 m / s). Therefore, autopilot 721 may plan paths and / or trajectories that accommodate the aircraft operating at the reduced capability.

[0155] In some embodiments, autopilot 721 may determine or adjust control commands sent to flight control system 721 based on the expected aircraft response and the current aircraft state. In some embodiments, autopilot 721 may directly transmit commands to aircraft flight elements (e.g., electric engines, control surface actuators etc.) based on the expected aircraft response. In some embodiments, based on the functions, autopilot 721 may transmit a target aircraft response to the FCS 722. For example, a target aircraft response may include an expected or desired response for the aircraft to undertake (e.g., based on a trajectory, endpoint, obstacles, sensor info, etc.).

[0156] While the above embodiments disclose determining an aircraft response and performing autopilot planning functions according to a current aircraft state, in other embodiments upcoming aircraft states are also considered. For example, in some embodiments, an estimate(s) of the aircraft response may be fed back into a function that determines saturation limit(s) and / or transfer function coefficients ). Therefore, multiple upcoming aircraft responses may be predicted and autopilot system 721 may perform functions based on the multiple upcoming aircraft responses.

[0157] As shown flowchart 782 of Fig. 71, in some embodiments, the FCS 722 may calculate transfer function coefficients (e.g., for transfer function 744) and saturation limits (e.g., constraints) based on the current aircraft state from state estimation function 741. These saturation limits and coefficients may then be transmitted to autopilot system 721 where they may be used to estimate the aircraft’s response and perform autopilot functions. In someembodiments, the saturation limits (e.g., constraints) and transfer function coefficients may require less frequent updates than state estimations. For example, they may be provided on demand as they change during a flight to limit the bandwidth usage during less dynamic phases of flight (e.g., flight phases outside of transitions).

[0158] Figs. 8A-8B2 illustrate flowcharts of situations where a flight control system may accept nudge control input, consistent with disclosed embodiments. Flow chart 783 shown in Fig. 8A, details how GPS error (“noise error”) 786 may impact a flight control system’s (e.g., FCS 722) ability to estimate an aircraft position 787 and control the aircraft to a target position (e.g., waypoint) 793. For example, signal blockage (e.g., via tall buildings and / or other obstacles), atmospheric conditions, and / or receiver malfunction may impact the ability of a flight control system (e.g., FCS 722) to estimate a location of the aircraft (e.g., estimated aircraft position 787) based on sensor data 788. Therefore, an actual approach may vary from an ideal approach as shown in diagram 979. Control laws 794 may incorrectly control the aircraft (e.g., by transmitting commands to actuators 795) based on faulty estimated position 789 to target position 793.

[0159] As the aircraft approaches a waypoint location (e.g., target position 793), the pilot may recognize that the actual aircraft location is offset from a displayed aircraft location. The pilot may use nudge control input to make adjustments to the trajectory while allowing autopilot 703 to maintain control of the aircraft, as shown in the two flowcharts 784 and 785 of Fig. 8B1-2 (and Fig. 8F, below).

[0160] Fig. 8B1 details a first embodiment where the pilot input device 796 may determine, generate, and / or transmit a nudge control input to adjust a target position 793 (e.g., waypoint) of an autopilot’s trajectory, similar to nudge control option 1 in Fig. 7D. As described above, an updated trajectory may be calculated (e.g., by autopilot 703, by a control stack, by an FCC), and the aircraft may be controlled according to the updated trajectory. The display 710 may update a displayed flight path and / or waypoint accordingly.

[0161] Fig. 8B2 flowchart details a second embodiment where pilot input device 796 may determine, generate, and / or transmit a nudge control input to correct an estimated position 789 of the aircraft (e.g., upon pilot detecting a GPS error, flight path error, etc.). In some embodiments, the corrected estimated location may be used to calculate an updated flight trajectory for the aircraft (e.g., by an autopilot 703). For example, a corrected location further from a landing pad may result in a more gradual deceleration. Further, display 710 may adjust the displayed aircraft location and / or flight path, while maintaining the displayed waypoint location. In some embodiments, a flight control system (e.g., FCS 722) may includeboth embodiments and the nudge control input device may allow a pilot to select the mode of nudge control input.

[0162] In some embodiments, a second input device (e.g., button, lever, user interface element, switch etc.) may be configured to accept a user input indicating whether the nudge control input is provided to adjust a target location (e.g., Fig. 8B1) or accommodate positioning error (e.g., Fig. 8B2) and provide the indication to a flight control system (e.g., FCS 722). Therefore, as further detailed below, a flight control system (e.g., FCS 722) may determine whether the display (e.g., display 710) should adjust a depiction of a target position or a position of the aircraft.

[0163] Fig. 8C illustrates an example embodiment where the autopilot system allows an acceleration and deceleration selection, consistent with the disclosed embodiments. As described above, in some embodiments, autopilot 703 may store different trajectories that are selectable and / or modifiable by a pilot. Autopilot 703 may include trajectories with acceleration profiles and deceleration profiles to reach set airspeeds, locations, and / or positions. For example, a pilot may select auto acceleration function 801 via an autoacceleration input device (e.g., a button, lever, inceptor, user interface element etc.) and the autopilot 703 may control the aircraft along an acceleration profile and / or trajectory for takeoff. Similarly, a pilot may select auto deceleration function 802 via an auto-decelerate input device (e.g., a button, lever, inceptor, user interface element etc.) and the autopilot 703 may control the aircraft along a deceleration profile for landing. In some embodiments, an acceleration selection may have a different effect based on current flight conditions and flight mode of the aircraft (e.g., powered lift enabled or disabled, as discussed below in paragraph

[0150] ).

[0164] In some embodiments, a pilot may maintain control of a heading of the aircraft (e.g., a pitch of the aircraft upwards and / or a turn angle of the aircraft), while in other embodiments autopilot 703 may store a flight path and control the aircraft along the path without pilot input. For example, an autopilot may store and / or receive a flight path (e.g., including a horizontal and / or vertical profile via waypoints) and selection of automatic acceleration or deceleration may guide the aircraft along the flight path without pilot input. In some embodiments, a pilot may select a flight path (e.g., which navigates around certain obstacles) corresponding to (e.g., ending at) a particular landing location and autopilot 703 may control the aircraft along the flight path upon a selection of auto-decelerate. In some embodiments, a pilot may specify an altitude, position, waypoint, and / or other navigation or task inputs (e.g.,via display 710), and an autopilot 703 may determine a flight path corresponding to the one or more pilot inputs.

[0165] In some embodiments, a flight mode selection may be performed by a pilot via a powered lift enable / disable input device to control an aircraft between powered lift disabled mode 803 and powered lift enabled mode 804. For example, a pilot may disable powered lift via a powered lift enable / disable input device if they prefer to land the aircraft in a predominantly horizontal manner (e.g., with lift predominantly (or only) provided by at least one wing or other flight surfaces, rather than propulsion systems, such as for CTOL). Based on receiving a selection of a powered lift disabled mode, an FCC (e.g., FCS 722) may discontinue commands (e.g., speed and / or torque commands) to electric propulsion systems. For example, a pilot may enable powered lift via a powered lift enable / disable to perform a vertical landing. For example, based on receiving a selection of a powered lift enabled mode, an FCC (e.g., FCS 722) may send commands (e.g., speed and / or torque commands) to an electric propulsion systems to provide powered lift (e.g., as a function of airspeed). Further, in some embodiments, a flight mode selection (e.g., on a powered lift enable / disabled switch) may enable a portion of an aircraft’s powered lift capabilities (e.g., to perform a vertical or short landing). The powered lift enable / disable switch may include one or more of physical switch, button, lever, and / or user interface element.

[0166] As shown, in powered lift disabled mode 803, a selection of auto-accelerate function 801 may cause the aircraft to accelerate to a rotation speed Vr (e.g., 80 knots) at which the aircraft may takeoff. In some embodiments, auto-accelerate function 801 may be disabled below a certain threshold speed to prevent a pilot from accidentally enabling acceleration to rotation speed Vr while the aircraft is taxiing on the ground. In some embodiments, a second input (e.g., on an auto-acceleration input device) may cause the aircraft to accelerate to a preferred range speed, Vrange. A preferred range speed may correspond to a speed at which the aircraft can achieve the longest flight range (e.g., most energy efficient). In some embodiments, the second input (e.g., on an auto-acceleration input device) may cause the aircraft to accelerate to a best climb speed (e.g., to avoid obstacles and / or achieve a desired altitude as quickly as possible). In some embodiments, a third input (e.g., on an autoacceleration input device) may cause the aircraft to accelerate to a cruise speed Vc. For example, in some embodiments, an autopilot 703 or flight control system may determine, retrieve, and / or receive a cruise speed based on how quickly an aircraft should reach a destination. For example, an individual can book a flight and indicate a required arrival time(e.g., on a mobile device) and autopilot 703 or flight control system may determine a required cruise speed to meet the arrival time based on a flight path.

[0167] In powered lift disabled mode 803, a selection of auto-decelerate function 802 may cause the aircraft to decelerate to an approach speed Vref (e.g., a speed designated by the airport and / or FAA in proximity to a landing site). In some embodiments, a second input (e.g., on an auto-decelerate input device) may cause the aircraft to decelerate to a touchdown speed Vtd. In some embodiments, a third input may automatically decelerate the aircraft to a stop (0 knots), while in other embodiments additional auto-deceleration is not available below touchdown speed Vtd. In some embodiments, when powered lift is partially enabled, the aircraft may be automatically decelerated to a short take-off landing speed (not shown).

[0168] In a powered lift enabled mode 804, a selection of auto-accel erate function 801 may cause the aircraft to accelerate to a best range speed Vref, as described above. In some embodiments, a second input (e.g., on an auto-accelerate input device) may cause the aircraft to accelerate to a cruise speed Vc.

[0169] In a powered lift enabled mode 804, a selection of auto-decelerate function 802 may cause the aircraft to decelerate to an approach speed, as described above. A second input (e.g., on an auto-decelerate input device) may cause the aircraft to decelerate to hover (0 knots).

[0170] In some embodiments, the effect(s) of a selection (e.g., acceleration or deceleration selection) may be provided to the pilot on display 710. For example, the display 710 may provide an airspeed the aircraft will reach, a location, a position, a flight path, and / or whether a selection is disabled.

[0171] Figs. 8D, 8E, and 8F illustrate examples of nudge control, consistent with the disclosed embodiments. Referencing Fig. 8D, at a first time step, the pilot may enable autopilot 703 (e.g., press an auto-descent button). Display 710 may lock waypoint 812a (e.g., a landing location) in place. Locking the waypoint may include fixing the location of the waypoint on the display, fixing the location of the waypoint relative to other displayed or displayable features (e.g., a map, trajectory, objects, etc.). Additionally or alternatively, locking the waypoint may include fixing the location of the waypoint within a flight path 813a (e.g., by an FCS 722 and / or autopilot 703). In some embodiments, the pilot may provide (e.g., after noting that the waypoint is off center of a landing area) a nudge control input (e.g., via a pilot input device, such as inceptors 702) to rotate waypoint 812a and / or flight path 813a clockwise towards the center of the landing area to final location waypoint and flight path locations (812b, 813b). In some embodiments, the rotated waypoint 812a may maintaina fixed radial distance from the aircraft during rotation. In some embodiments, autopilot 703 (or, e.g., FCS 722) may adjust the trajectory of the aircraft such that the heading of the aircraft changes based on an amount of nudge control input, but the decent profile (e.g., deceleration profile) will remain the same. Therefore, adjusted waypoint 812b will be the same distance from the aircraft. An amount of nudge control input may be determined based on a length of time during which an input mechanism (e.g., button, switch, knob, touch surface, etc.) is interacted with (e.g., pressed, held, touched) by a user, a number of time an input mechanism is interacted with by a user, and / or an amount of force applied to the mechanism (e.g., amount of rotation given to a knob, amount of pressure applied at a touch surface, etc.). At a second time step, this adjusted waypoint 812b and / or path 813b is displayed, and the aircraft is controlled via autopilot to the adjusted waypoint location.

[0172] Referencing Fig. 8E, at a first time step, the pilot may enable autopilot (e.g., press a deceleration button). Display 710 may lock waypoint 812c (e.g., a landing location) in place, which may include any of the aspects discussed above with respect to Fig. 8D. The pilot may provide (e.g., after noting that the waypoint is off center of a landing area) a nudge control input (e.g., via a pilot input device) to shift waypoint 812c and / or flight path 813c backward towards the center of the landing area to a final locations 812d, 813d. FCS 722 (and / or autopilot 703) may determine a new (e.g., updated, replacement, and / or otherwise adjusted) trajectory (e.g., deceleration profile) to accommodate the adjusted waypoint 812d location (e.g., based on determining or detecting the change in relative position between waypoint 812 and the aircraft). At a second time step, the adjusted waypoint 812d and / or path 813d is displayed, and the aircraft is controlled via autopilot 703 to the adjusted waypoint location.

[0173] While the examples in Fig. 8D and 8E illustrate controlling only one of an aircraft heading or acceleration based on the nudge control input, in other embodiments both heading and acceleration may be controlled. For example, a pilot may select an adjusted waypoint that is both closer to the aircraft and at a different heading and the flight control system may control the aircraft to the adjusted waypoint location.

[0174] Fig. 8F illustrates an example of nudge control, consistent with the disclosed embodiments. As described above, a pilot may notice that their surroundings are inconsistent with the displayed flight path 813e and / or waypoint 812e (e.g., due to GPS error) and use nudge control (e.g., via a pilot input device) to make adjustments. For example, displayed flight path 813e (as shown by initial display 814) may show the aircraft is (or will be) further from a landing pad than the pilot observes (as shown by pilot observation 815). The pilot may input at least one nudge control input (e.g., via a pilot input device, such as inceptors 702) toupdate the trajectory to reflect the surroundings (e.g., correct a location of the aircraft longitudinally forward). Flight control system 722 (and / or autopilot 703) may determine a new (e.g., updated, replacement) trajectory (e.g., deceleration profile) to accommodate the adjusted aircraft position (e.g., based on determining or detecting the change in relative position between waypoint 812e and the aircraft). In some embodiments, display 710 may update the path (e.g., as shown by path 813f), and / or background scenery based on the at least one nudge control input (as shown in corrected display 816).

[0175] Fig. 8G illustrates an example of nudge control, consistent with the disclosed embodiments. As described above, in some embodiments, autopilot 703 may store, generate, and / or modify multiple trajectories that are selectable by a pilot. For example, autopilot 703 may store trajectories to maneuver around buildings or other obstacles and / or fly the aircraft according to a descent and / or ascent profile. In some embodiments, one or more processors (e.g., associated with an FCC and / or autopilot) may be configured to, while autopilot 703 is disabled, (a) move displayed waypoint 812g location based on a current state (e.g., one or more of a heading, position, speed, location, orientation, or flight phase) of the aircraft and (b) control the aircraft based on at least one pilot inceptor (e.g., manual pilot input). As detailed in Fig. 8G, at a first time step, with autopilot 703 disabled, waypoint 812g associated with an upcoming autopilot trajectory may move with the aircraft. For example, display 710 described above may show the flight path 813g and waypoint 812g of an upcoming trajectory. Therefore, the pilot may be aware of the impact of selecting autopilot (e.g., by pushing a deceleration button). At a second time step, the pilot may enable autopilot (e.g., press a deceleration button). The display 710 may lock waypoint 812h (e.g., a landing location) and flight path 813h in place (e.g., until receiving an input). The pilot may then note that waypoint 812h is off center in a landing area. At a third time step, the pilot may adjust waypoint 812h with nudge control input (e.g., on a pilot input device) to shift waypoint 812h towards the center of a landing area as shown by waypoint 812i . FCS 722 may determine a new trajectory (e.g., descent profile, such as a deceleration profile and / or positioning profile) to accommodate the adjusted waypoint 812i location (e.g., based on determining or detecting the change in relative position between the aircraft and waypoint 812i and / or associated trajectory). The adjusted waypoint 812i and / or updated flight path 813i is displayed, and the aircraft is controlled via autopilot to the adjusted waypoint 812i location.

[0176] Fig. 8H illustrates an example of nudge control inputs, consistent with the disclosed embodiments. As described above, in some embodiments, pilot inceptors 702 may allow the pilot to provide nudge control input. In some embodiments, pilot inceptors 702 may receive apilot’s deflection and generate a different response based on whether autopilot 703 has been enabled (e.g., a nudge response as opposed to traditional manual control). For example, as shown in example 1, a first pilot inceptor (e.g., a right inceptor) may allow a pilot to rotate a waypoint 812j CW or CCW about the aircraft (e.g., from 812j -812k) by moving the inceptor left or right of a neutral position (. A first inceptor (e.g., a right inceptor) may allow a pilot to translate waypoint away from the aircraft (e.g., as shown in Fig. 8E above) by moving the inceptor forward or back of a neutral position. As shown in example 2, a second inceptor (e.g., a left inceptor) may allow a pilot to shift waypoint 8121 left relative to the aircraft (e.g., left relative to a forward direction of the aircraft, such as from 8121-812m) or right relative to the aircraft (e.g., right relative to a forward direction of the aircraft) by moving the inceptor left or right of a neutral position. As shown in example 3, a second inceptor (e.g., a left inceptor) may allow a pilot to increase or decrease an altitude of waypoint 812n (e.g., from 812n-812o) by moving the inceptor forward or back of a neutral position.

[0177] While the above combinations provide one example of how the inceptors may be configured to provide nudge control, the disclosure is not so limited. For example, a first inceptor may be a left inceptor and a second inceptor may be a right inceptor. Further, any combination of functions is possible. For example, any combination of two functions: CW / CCW rotation, forward / back translation, left / right shifting, or increase / decrease altitude may be included on either one of the two inceptors.

[0178] In some embodiments, one or more of the left and right inceptors are configured to accept pilot input during manual flight. A flight control system may respond differently to the inceptor input based on whether or not an autopilot of the aircraft is enabled.

[0179] Figs. 8I-8J illustrate an example of nudge control inputs and aircraft control, consistent with the disclosed embodiments. As described above, at a first step with autopilot 703 disengaged a waypoint 812 and / or flight path along an associated trajectory continues to move as the aircraft approaches the landing area. At a second time step, the pilot may notice the waypoint 812 is roughly aligned with the target landing area 811 and engage autopilot 703 (e.g., select auto-land and / or auto-decelerate) which locks the waypoint into place. At a third time step, autopilot 703 will continue to adjust the control of the aircraft to the locked waypoint 812 (e.g., speed and / or positioning control). At fourth and fifth time steps, the pilot may notice that the locked waypoint 812 is not aligned with the target landing site 811 and may first move a first inceptor forward in order to move the waypoint away from the aircraft and then move a first inceptor to the right to align it with the desired landing area (or vice versa).

[0180] Figs. 8K-8M illustrate examples of a pilot interceptor device and associated control, consistent with the disclosed embodiments. The pilot inceptor devices and control illustrated may be incorporated into any of the above embodiments (e.g., pilot inceptor(S) 702 etc.). Fig. 8K illustrates components of an exemplary flight control apparatus 830, consistent with disclosed embodiments. As shown in FIG. 8K , embodiments of a flight control apparatus for an aircraft may include inceptors 831 and 832 (e.g., joysticks, sticks, controllers, etc.), thumb sticks 833 and 834, at least one processor 835, at least one memory 836, one or more sensors 837, actuators 838, and engines 839. Inceptors 831 and 832 may be any input devices in the form of a stick, such as a joystick or an inceptor, configured to control movement of an aircraft via manual inputs (e.g., inceptor movements) received from a user (e.g., pilot). In some embodiments, the inceptors may be located at a specific position relative to a pilot of the aircraft. For example, one of the inceptors may be located to the left of the pilot (i.e., left inceptor 831) and the other inceptor may be located to the right of the pilot (i.e., right inceptor 832). In some embodiments, each inceptor may have one or more sensors integrated onto the inceptor configured to respond to a force applied via movement of the inceptor by generating and transmitting electronic signals corresponding to movement of the inceptor to processor 835. Additionally or alternatively, each inceptor may comprise a force-feedback component configured to receive control signals from a flight control computer of the flight control apparatus and to apply counter forces based on the received control signals. Thumb sticks 833 and 834, as discussed below, may be configured to act as beep inceptors. In some embodiments, thumb stick 833 and 834 may act as a replacement inceptor for its corresponding inceptor in response to receiving an override signal. Processor 835 may be any processing unit (e.g., computing device, microcontroller, microprocessor, system-on-chip, digital signal processor, etc.) configured to perform operations based on instructions stored in one or more memories, such as memory 836. Sensor(s) 837 may be any sensors configured to measure data associated with the aircraft. For example, one or more sensors 837 may be configured to measure one or more of an airspeed, groundspeed, temperature, acceleration(s), static pressure, angular rate, location (e.g., GPS), attitude, altitude, heading, etc. associated with the aircraft. Actuators 838 may include actuators that can be controlled to move flight control surfaces. Engines 839 may include propulsion engines, as discussed above.

[0181] Fig. 8L shows a diagram 840 illustrating exemplary movements of the inceptors 831, 832, consistent with disclosed embodiments. As shown in FIG. 8L , in some embodiments, each inceptor 831, 832 may be configured to move longitudinally (i.e., up / forward and down / aft) and / or laterally (i.e., right and left) on a base, wherein each longitudinal and lateralmovement and resulting inceptor position may be interpreted as a digital value to be input into the at least one processor and output as signals to various electrical and mechanical components of the aircraft. For example, based on the longitudinal and lateral movements of the inceptors 831, 832, the at least one processor may be configured to output signals to change an amount of thrust provided to each motor. As another example, based on the longitudinal and lateral movements of the inceptors 831, 832, the at least one processor may be configured to change a shape and / or orientation of airfoils (e.g., one or more control surfaces).

[0182] Fig. 8M shows an exemplary table 850 of control mapping associated with the inceptors 831, 832, consistent with disclosed embodiments. As shown in FIG. 8M, in some embodiments, the at least one processor (e.g., of control stack 720 above) may be configured to determine how inceptor movement impacts aircraft control based on a flight phase (e.g., hover 841, transition 842, CTOL 843) of the aircraft.

[0183] As shown in Figs. 8H, 8J, and 8L-M, FCS 722 and / or autopilot system 703 are configured to respond to the deflection on the pilot input device (e.g, pilot inceptor 702) differently based on whether the autopilot system is enabled. FCS 722 and / or autopilot system 703 are configured to, while autopilot 703 is enabled, interpret the deflection as corresponding to a position change of a waypoint (e.g., waypoint 812), and, while autopilot 703 is not enabled, interpret the deflection as corresponding to at least one of: an orientation or speed change for the aircraft (e.g., as shown in Fig. 8K).

[0184] The embodiments may further be described using the following clauses:1. An aircraft, comprising: an autopilot system configured to control the aircraft based on stored flight trajectory information; and a flight control system configured to provide a limit to the autopilot system, wherein the limit is based on at least one of: a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft, wherein the autopilot system is configured to determine one or more commands based on the limit received from the flight control system and provide the one or more commands to the flight control system to control the aircraft.2. The aircraft of clause 1, wherein the one or more commands determined by the autopilot system are configured to adjust a trajectory of the aircraft.3. The aircraft of clause 1, wherein the one or more commands determined by the autopilot system are configured to adjust a trajectory of the aircraft to a target trajectory determined by the autopilot system.4. The aircraft of clause 2 or 3, wherein the one or more commands determined by the autopilot system are configured to control the aircraft along the adjusted trajectory.5. The aircraft of any of clauses 1-4, wherein the flight control system is configured to provide the limit based on the state of high voltage distribution, including at least one of: a state of one or more switching devices, a state of one or more fuses, a state of one or more batteries, or a wiring temperature.6. The aircraft of any of clauses 1-5, wherein the limit is based on a temperature of an electric engine.7. The aircraft of any of clauses 1-6, wherein the flight control system is configured to vary the limit based on the flight phase of the aircraft.8. The aircraft of any of clauses 1-7, wherein the limit comprises at least one airspeed, roll rate, turn rate, climb rate, or descent rate, and the aircraft and the at least one limit is dependent on the flight phase of the aircraft.9. The aircraft of any of clauses 1-8, wherein a value of the limit is dependent on the flight phase of the aircraft, and the flight control system is configured to provide an appropriate value of the limit to the autopilot system associated with the flight phase of the aircraft.10. The aircraft of any of clauses 1-9, wherein the limit defines a boundary of a response of the aircraft.11. The aircraft of clause 10, wherein the autopilot is configured to use the limit in a transfer function to determine an expected response of the aircraft.12. The aircraft of clause 11, wherein the autopilot is configured to perform path planning based on the expected aircraft response.13. The aircraft of any of clauses 1-12, wherein the flight control system comprises one or more control loops and is configured to adjust the one or more provided commands using the one or more control loops to maintain the stability of the aircraft.14. The aircraft of any of clauses 1-13, wherein the flight control system is configured to provide the limit more frequently in a transition phase of flight than in a hover phase of flight.15. The aircraft of any of clauses 1-14, wherein the limit establishes a boundary for an aircraft orientation or movement.16. A system, comprising:an autopilot system configured to control an aircraft based on stored flight trajectory information; and a flight control system configured to provide a limit to the autopilot system, wherein the limit is based on at least one of a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft, wherein the autopilot system is configured to determine one or more commands based on the limit received from the flight control system and provide the one or more commands to the flight control system to control the aircraft.17. A computer-implemented method for an aircraft, comprising: controlling, by an autopilot system, an aircraft based on stored flight trajectory information; providing, by a flight control system, a limit to the autopilot system, wherein the limit is based on at least one of a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft; and determining, by the autopilot system, one or more commands based on the limit received from the flight control system and providing the one or more commands to the flight control system to control the aircraft.18. A computer readable medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform the computer-implemented method of clause 17.19. An aircraft comprising: an autopilot system configured to control the aircraft to travel along a flight trajectory based on stored flight trajectory information, wherein the stored flight trajectory information includes a descent profile; a display configured to display a waypoint at an end of the flight trajectory; and one or more processors configured to, while the autopilot system is enabled: control the aircraft according to the stored trajectory information via the autopilot system; receive an input from a pilot input device; determine a change in relative position between the waypoint and the aircraft based on the received input; adjust the flight trajectory based on the determined change in relative position, including adjusting the descent profile; and control the aircraft based on the adjusted flight trajectory.20. The aircraft of clause 19, further comprising: the pilot input device, wherein the pilot input device is a pilot inceptor; and wherein the one or more processors are configured to control the aircraft based on the input from the pilot input device caused by a deflection of the pilot input device while the autopilot system is not enabled.21. The aircraft of clause 20, wherein the one or more processors are configured to respond to the deflection on the pilot input device differently based on whether the autopilot system is enabled, and wherein, while the autopilot system is enabled, the deflection corresponds to a position change of the waypoint, and wherein while the autopilot system is not enabled, the deflection corresponds to at least one of: an orientation or speed change for the aircraft.22. The aircraft of any of clauses 19-21, wherein the input from the pilot input device causes at least one of the following actions to be performed: rotate the waypoint a fixed distance about the aircraft, shift the waypoint left relative to a forward direction of the aircraft, or shift the waypoint right relative to a forward direction of the aircraft.23. The aircraft of any of clauses 19-22, wherein the autopilot system is disabled when the input is greater than or equal to a threshold.24. The aircraft of any of clauses 19-23, wherein the one or more processors are further configured to cause display of the determined relative position between the aircraft and the waypoint on the display.25. The aircraft of clause 24, wherein the one or more processors are further configured to control the display to: maintain a location of the displayed waypoint when there is an aircraft positioning error, and adjust a location of the displayed waypoint when there is no aircraft positioning error.26. The aircraft of any of clauses 19-25, wherein the one or more processors are further configured to: display the waypoint at a set distance away from the aircraft on the display while the autopilot is disabled; and lock the waypoint location upon receiving an indication to perform an auto-descent,wherein the controlling the aircraft according to the stored trajectory information comprises controlling the aircraft along the descent profile to end at the locked waypoint location.27. The aircraft of any of clauses 19-26, further comprising a switching device configured to enable the autopilot system based on at least one of a flight condition or a manual selection.28. The aircraft of any of clauses 19-27, wherein the descent profile comprises at least one of: an airspeed or position along the trajectory.29. The aircraft of any of clauses 19-28, wherein the autopilot system is further configured to control the aircraft to a set speed based on a flight mode of the aircraft.30. The aircraft of clause 29, wherein the aircraft comprises a powered lift mode of operation and the autopilot system is configured to decelerate the aircraft to a touchdown speed when the powered lift mode of operation is disabled and decelerate the aircraft to a hover speed when the powered lift mode of operation is enabled.31. A system, comprising: an autopilot system configured to control an aircraft to travel along a flight trajectory based on stored flight trajectory information, wherein the stored flight trajectory information includes a descent profile; a display configured to display a waypoint at an end of the flight trajectory; and one or more processors configured to, while the autopilot system is enabled: control the aircraft according to the stored trajectory information via the autopilot system; receive an input from a pilot input device; determine a change in relative position between the waypoint and the aircraft based on the received input; adjust the flight trajectory based on the determined change in relative position, including adjusting the descent profile; and control the aircraft based on the adjusted flight trajectory.32. A computer-implemented method for an aircraft, comprising: controlling, by an autopilot system, the aircraft to travel along a flight trajectory based on stored flight trajectory information, wherein the stored flight trajectory information includes a descent profile; displaying a waypoint at an end of the flight trajectory; and receiving an input from a pilot input device;determining a change in relative position between the waypoint and the aircraft based on the received input; adjusting the flight trajectory based on the determined change in relative position, including adjusting the descent profile; and controlling, by the autopilot system, the aircraft based on the adjusted flight trajectory.33. A computer readable medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform the computer-implemented method of clause 32.

[0185] The foregoing description has been presented for purposes of illustration. It is not exhaustive and does not limit the invention to the precise forms or embodiments disclosed. Modifications and adaptations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed embodiments of the inventions disclosed herein.

[0186] The features and advantages of the disclosure are apparent from the detailed specification, and thus, it is intended that the appended claims cover all systems and methods falling within the true spirit and scope of the disclosure. As used herein, the indefinite articles “a” and “an” mean “one or more.” Similarly, the use of a plural term does not necessarily denote a plurality unless it is unambiguous in the given context. Words such as “and” or “or” mean “and / or” unless specifically directed otherwise. As used herein, unless specifically stated otherwise, being “based on” may include being dependent on, being interdependent with, being associated with, being defined at least in part by, being derived from, being influenced by, or being responsive to. As used herein, “related to” may include being inclusive of, being expressed by, being indicated by, or being based on. Further, since numerous modifications and variations will readily occur from studying the present disclosure, it is not desired to limit the disclosure to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the disclosure.

[0187] Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the implementations disclosed herein. It is intended that the architectures and arrangements shown in figures are only for illustrative purposes and are not intended to be limited to the specific arrangements and circuit arrangements as described and shown in the figures. It is also intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by thefollowing claims. The foregoing description has been presented for purposes of illustration. It is not exhaustive and does not limit the invention to the precise forms or embodiments disclosed. Modifications and adaptations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed embodiments of the inventions disclosed herein.

[0188] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0189] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Claims

CLAIMS1. An aircraft, comprising: an autopilot system configured to control the aircraft based on stored flight trajectory information; and a flight control system configured to provide a limit to the autopilot system, wherein the limit is based on at least one of: a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft, wherein the autopilot system is configured to determine one or more commands based on the limit received from the flight control system and provide the one or more commands to the flight control system to control the aircraft.

2. The aircraft of claim 1, wherein the one or more commands determined by the autopilot system are configured to adjust a trajectory of the aircraft.

3. The aircraft of claim 1, wherein the one or more commands determined by the autopilot system are configured to adjust a trajectory of the aircraft to a target trajectory determined by the autopilot system.

4. The aircraft of claim 2 or 3, wherein the one or more commands determined by the autopilot system are configured to control the aircraft along the adjusted trajectory.

5. The aircraft of any of claims 1-4, wherein the flight control system is configured to provide the limit based on the state of high voltage distribution, including at least one of: a state of one or more switching devices, a state of one or more fuses, a state of one or more batteries, or a wiring temperature.

6. The aircraft of any of claims 1-5, wherein the limit is based on a temperature of an electric engine.

7. The aircraft of any of claims 1-6, wherein the flight control system is configured to vary the limit based on the flight phase of the aircraft.

8. The aircraft of any of claims 1-7, wherein the limit comprises at least one airspeed, roll rate, turn rate, climb rate, or descent rate, and the aircraft and the at least one limit is dependent on the flight phase of the aircraft.

9. The aircraft of any of claims 1-8, wherein a value of the limit is dependent on the flight phase of the aircraft, and the flight control system is configured to provide an appropriate value of the limit to the autopilot system associated with the flight phase of the aircraft.

10. The aircraft of any of claims 1-9, wherein the limit defines a boundary of a response of the aircraft.

11. The aircraft of claim 10, wherein the autopilot is configured to use the limit in a transfer function to determine an expected response of the aircraft.

12. The aircraft of claim 11, wherein the autopilot is configured to perform path planning based on the expected aircraft response.

13. The aircraft of any of claims 1-12, wherein the flight control system comprises one or more control loops and is configured to adjust the one or more provided commands using the one or more control loops to maintain the stability of the aircraft.

14. The aircraft of any of claims 1-13, wherein the flight control system is configured to provide the limit more frequently in a transition phase of flight than in a hover phase of flight.

15. The aircraft of any of claims 1-14, wherein the limit establishes a boundary for an aircraft orientation or movement.

16. A system, comprising: an autopilot system configured to control an aircraft based on stored flight trajectory information; and a flight control system configured to provide a limit to the autopilot system, wherein the limit is based on at least one of: a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft, wherein the autopilot system is configured to determine one or more commands based on the limit received from the flight control system and provide the one or more commands to the flight control system to control the aircraft.

17. A computer-implemented method for an aircraft, comprising: controlling, by an autopilot system, an aircraft based on stored flight trajectory information; providing, by a flight control system, a limit to the autopilot system, wherein the limit is based on at least one of: a state of high voltage distribution, a state of an electric engine, or a flight phase of the aircraft; and determining, by the autopilot system, one or more commands based on the limit received from the flight control system and providing the one or more commands to the flight control system to control the aircraft.

18. A computer readable medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform the computer-implemented method of claim 17.

19. An aircraft comprising: an autopilot system configured to control the aircraft to travel along a flight trajectory based on stored flight trajectory information, wherein the stored flight trajectory information includes a descent profile; a display configured to display a waypoint at an end of the flight trajectory; and one or more processors configured to, while the autopilot system is enabled: control the aircraft according to the stored trajectory information via the autopilot system; receive an input from a pilot input device; determine a change in relative position between the waypoint and the aircraft based on the received input; adjust the flight trajectory based on the determined change in relative position, including adjusting the descent profile; and control the aircraft based on the adjusted flight trajectory.

20. The aircraft of claim 19, further comprising: the pilot input device, wherein the pilot input device is a pilot inceptor; and wherein the one or more processors are configured to control the aircraft based on the input from the pilot input device caused by a deflection of the pilot input device while the autopilot system is not enabled.

21. The aircraft of claim 20, wherein the one or more processors are configured to respond to the deflection on the pilot input device differently based on whether the autopilot system is enabled, and wherein, while the autopilot system is enabled, the deflection corresponds to a position change of the waypoint, and wherein while the autopilot system is not enabled, the deflection corresponds to at least one of: an orientation or speed change for the aircraft.

22. The aircraft of any of claims 19-21, wherein the input from the pilot input device causes at least one of the following actions to be performed: rotate the waypoint a fixed distance about the aircraft,shift the waypoint left relative to a forward direction of the aircraft, or shift the waypoint right relative to a forward direction of the aircraft.

23. The aircraft of any of claims 19-22, wherein the autopilot system is disabled when the input is greater than or equal to a threshold.

24. The aircraft of any of claims 19-23, wherein the one or more processors are further configured to cause display of the determined relative position between the aircraft and the waypoint on the display.

25. The aircraft of claim 24, wherein the one or more processors are further configured to control the display to: maintain a location of the displayed waypoint when there is an aircraft positioning error, and adjust a location of the displayed waypoint when there is no aircraft positioning error.

26. The aircraft of any of claims 19-25, wherein the one or more processors are further configured to: display the waypoint at a set distance away from the aircraft on the display while the autopilot is disabled; and lock the waypoint location upon receiving an indication to perform an auto-descent, wherein the controlling the aircraft according to the stored trajectory information comprises controlling the aircraft along the descent profile to end at the locked waypoint location.

27. The aircraft of any of claims 19-26, further comprising a switching device configured to enable the autopilot system based on at least one of a flight condition or a manual selection.

28. The aircraft of any of claims 19-27, wherein the descent profile comprises at least one of: an airspeed or position along the trajectory.

29. The aircraft of any of claims 19-28, wherein the autopilot system is further configured to control the aircraft to a set speed based on a flight mode of the aircraft.

30. The aircraft of claim 29, wherein the aircraft comprises a powered lift mode of operation and the autopilot system is configured to decelerate the aircraft to a touchdown speed when the powered lift mode of operation is disabled and decelerate the aircraft to a hover speed when the powered lift mode of operation is enabled.

31. A system, comprising:an autopilot system configured to control an aircraft to travel along a flight trajectory based on stored flight trajectory information, wherein the stored flight trajectory information includes a descent profile; a display configured to display a waypoint at an end of the flight trajectory; and one or more processors configured to, while the autopilot system is enabled: control the aircraft according to the stored trajectory information via the autopilot system; receive an input from a pilot input device; determine a change in relative position between the waypoint and the aircraft based on the received input; adjust the flight trajectory based on the determined change in relative position, including adjusting the descent profile; and control the aircraft based on the adjusted flight trajectory.

32. A computer-implemented method for an aircraft, comprising: controlling, by an autopilot system, the aircraft to travel along a flight trajectory based on stored flight trajectory information, wherein the stored flight trajectory information includes a descent profile; displaying a waypoint at an end of the flight trajectory; and receiving an input from a pilot input device; determining a change in relative position between the waypoint and the aircraft based on the received input; adjusting the flight trajectory based on the determined change in relative position, including adjusting the descent profile; and controlling, by the autopilot system, the aircraft based on the adjusted flight trajectory.

33. A computer readable medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform the computer-implemented method of claim 32.

Images