Systems and methods for vibration damping in aircraft flight control

Abstract

This disclosure relates, in general, to flight control of electric aircraft and other powered aircraft vehicles. In one embodiment, an electric system for an aircraft is disclosed, comprising at least one processor, the at least one processor configured to receive pilot input indicating a commanded aircraft state, determine aircraft thrust to achieve the commanded aircraft state, and extract at least one propeller parameter associated with propeller speed, the propeller parameter being determined to reduce structural vibration response in the aircraft. The at least one processor is further configured to determine a respective command for each propeller of the aircraft to achieve the determined aircraft thrust based on the at least one propeller parameter, and to control each propeller of the aircraft based on the corresponding respective command.

Description

Technical Field

[0001] Cross - reference to Related Applications This disclosure claims priority to U.S. Provisional Application No. 63 / 504,958, filed May 30, 2023, titled "SYSTEMS AND METHODS FOR FLIGHT CONTROL OF EVTOL AIRCRAFT" (Attorney Docket No. 16163.6011 - 00000), and U.S. Provisional Application No. 63 / 578,075, filed Aug. 22, 2023, titled "SYSTEMS AND METHODS FOR FLIGHT CONTROL OF EVTOL AIRCRAFT" (Attorney Docket No. 16163.6020 - 00000). The entire contents of the above applications are hereby incorporated by reference for all purposes.

[0002] This disclosure generally relates to powered aircraft. More specifically, and without limitation, this disclosure relates to technological innovations in aircraft driven by electric propulsion systems. Certain aspects of this disclosure generally relate to flight control of aircraft driven by electric propulsion systems and in other types of vehicles, as well as systems and methods for flight control of aircraft in flight simulators and video games. Other aspects of this disclosure generally relate to improvements in flight control systems and methods that provide certain advantages to aircraft and that can be used in other types of vehicles.

Background Art

[0003] The inventors of the present invention have come to recognize several problems that may be associated with the flight control of aircraft, including tiltrotor aircraft using electric propulsion systems or hybrid electric propulsion systems (hereinafter referred to as electric propulsion units or "EPUs"). For example, aircraft propellers pose a risk of causing significant vibrations in the aircraft when multiple propellers rotate at the same speed (e.g., RPM). Furthermore, each aircraft propeller may experience significant vibrations within a certain speed range. These speed ranges in which significant vibrations occur may vary based on the aircraft's airspeed and the propeller's tilt angle.

[0004] These vibrations can be transmitted through the engine and aircraft structure to the inertial measurement unit (IMU) included in the onboard sensing equipment. Therefore, significant vibrations can affect the flight control system. to This can disrupt aircraft state estimates based on IMU measurements, potentially leading to high-frequency commands being sent to flight elements (e.g., actuators, control surfaces, and engines). These high-frequency commands can result in increased power consumption, higher temperatures, increased cycle and wear, and contribute to increased cabin and community noise, as well as a reduced ride comfort.

[0005] Furthermore, these vibrations can cause electric engines to operate inefficiently, affect the controllability and stability of the aircraft, increase the load on the aircraft structure, and cause structural fatigue of different aircraft components. For example, propeller vibrations can affect the propeller's ability to respond to flight control commands (e.g., propeller torque and / or tilt angle), cause the propeller angle to exceed the desired operating range, and / or strain or damage aircraft components such as the connection points between the propeller and the aircraft. Bending failures or other types of damage to the aircraft (potentially catastrophic) may result. Vibrations can also cause cabin movement and acoustic noise, reducing the ride comfort for aircraft passengers.

[0006] This problem can be particularly serious in aircraft with multiple propellers, a common configuration in many electric aircraft (e.g., multi-rotor aircraft). In particular, if the propeller speeds of multiple propellers are the same, the vibrations of multiple propellers can amplify the shock. Furthermore, detecting which propeller(s) are causing the vibration, and controlling the aircraft to reduce the vibration, can be especially difficult. [Overview of the Initiative]

[0007] This disclosure relates, in general, to flight control of electric aircraft and other powered aircraft. More specifically, and not limited to, this disclosure relates to technological innovations for tiltrotor aircraft using electric propulsion systems. Certain aspects of this disclosure relate to controlling aircraft propeller speeds so that multiple propellers rotate at the same speed and to avoid increasing aircraft vibration. Other aspects of this disclosure relate to controlling each propeller to avoid certain speed ranges where vibration is more severe. Further aspects of this disclosure relate to implementing the above propeller control while maintaining the thrust required to respond to pilot commands.

[0008] One aspect of the present disclosure relates to an electrical system for an aircraft, the electrical system comprising at least one processor, the at least one processor configured to receive pilot input indicating a commanded aircraft state, determine aircraft thrust to achieve the commanded aircraft state, extract at least one propeller parameter associated with propeller speed, the propeller parameter determined to reduce structural vibration response in the aircraft, determine a respective command for each propeller of the aircraft to achieve the determined aircraft thrust based on the at least one propeller parameter, and control each propeller of the aircraft based on the corresponding respective command.

[0009] Another aspect of the present disclosure relates to an aircraft including at least one processor, the at least one processor configured to receive pilot input indicating a commanded aircraft state, determine aircraft thrust to achieve the commanded aircraft state, extract at least one propeller parameter associated with propeller speed, the propeller parameter determined to reduce structural vibration response in the aircraft, determine a respective command for each propeller of the aircraft to achieve the determined aircraft thrust based on the at least one propeller parameter, and control each propeller of the aircraft based on the corresponding respective command.

[0010] A further aspect of the present disclosure relates to a method for controlling an aircraft, the method comprising: receiving a pilot input indicating a commanded aircraft state; determining an aircraft thrust to achieve the commanded aircraft state; extracting at least one propeller parameter associated with propeller speed, the propeller parameter being determined to reduce structural vibration response in the aircraft; determining a respective command for each propeller of the aircraft to achieve the determined aircraft thrust based on the at least one propeller parameter; and controlling each propeller of the aircraft based on the corresponding respective command. [Brief explanation of the drawing]

[0011] [Figure 1] An exemplary vertical take-off and landing (VTOL) aircraft consistent with the disclosed embodiments is shown. [Figure 2] An exemplary VTOL aircraft consistent with the disclosed embodiments is shown. [Figure 3] An exemplary top view of a VTOL aircraft, consistent with the disclosed embodiments, is shown. [Figure 4] An exemplary propeller rotation of a VTOL aircraft, consistent with the disclosed embodiments, is illustrated. [Figure 5] This shows an exemplary power connection in a VTOL aircraft, consistent with the disclosed embodiments. [Figure 6] This is a schematic block diagram of an exemplary architecture and design of an electric propulsion power and control system consistent with the disclosed embodiments. [Figure 7] An exemplary top view of a VTOL aircraft, consistent with the disclosed embodiments, is shown. [Figure 8] This is a schematic example of a flight control signaling architecture for controlling a control surface and associated actuators, consistent with the disclosed embodiments. [Figure 9A] An exemplary top view of a VTOL aircraft, consistent with the disclosed embodiments, is illustrated. [Figure 9B] An exemplary top view of a VTOL aircraft, consistent with the disclosed embodiments, is illustrated. [Figure 9C] An exemplary top view of a VTOL aircraft, consistent with the disclosed embodiments, is illustrated. [Figure 9D] An exemplary top view of a VTOL aircraft, consistent with the disclosed embodiments, is illustrated. [Figure 9E] An exemplary top view of a VTOL aircraft, consistent with the disclosed embodiments, is illustrated. [Figure 10] A functional block diagram illustrating an exemplary control system for an electric VTOL aircraft, consistent with the disclosed embodiments, is provided. [Figure 11] The effect of vibration on a signal, consistent with the disclosed embodiments, is illustrated. [Figure 12] We illustrate a scenario in which vibrations may be more severe, consistent with the disclosed embodiments. [Figure 13] We illustrate another scenario in which vibrations may be more severe, consistent with the disclosed embodiments. [Figure 14] An example of aircraft control for vibration damping, consistent with the disclosed embodiments, is illustrated. [Figure 15] An aerodynamic model consistent with the disclosed embodiments is illustrated. [Figure 16A] Exemplary instructions for vibration damping based on avoiding the propeller no-go zone, consistent with the disclosed embodiments, are illustrated. [Figure 16B] Illustrate exemplary commands for vibration attenuation based on avoiding the propeller prohibited zone, which is consistent with the disclosed embodiments. [Figure 16C] Illustrate a process for avoiding propeller speeds with elevated vibrations, which is consistent with the disclosed embodiments. [Figure 16D] Illustrate another process for avoiding propeller speeds with elevated vibrations, which is consistent with the disclosed embodiments. [Figure 16E] Illustrate another process for avoiding propeller speeds with elevated vibrations, which is consistent with the disclosed embodiments. [Figure 17A] Illustrate a block diagram for vibration attenuation based on dividing propeller speeds among multiple propellers using a feed-forward configuration, which is consistent with the disclosed embodiments. [Figure 17B] Illustrate another block diagram for vibration attenuation based on dividing propeller speeds among multiple propellers using a feedback configuration, which is consistent with the disclosed embodiments. [Figure 17C] Illustrate a block diagram showing how the propeller speed difference is commanded, which is consistent with the disclosed embodiments. [Figure 17D] Illustrate a torque command for offsetting the propeller speed, which is consistent with the disclosed embodiments.

Mode for Carrying Out the Invention

[0012] This disclosure primarily describes systems, components, and technologies for use in aircraft. Aircraft may be piloted aircraft, unpiloted aircraft (e.g., UAVs), drones, helicopters, and / or airplanes. An aircraft comprises a physical body and one or more components (e.g., wings, tails, propellers) configured to enable the aircraft to fly. An aircraft may include any configuration including at least one propeller. In some embodiments, an aircraft is driven by one or more electric propulsion systems (hereinafter referred to as electric propulsion units or "EPUs"). Aircraft may be fully electric, hybrid, or gas-powered. For example, in some embodiments, an aircraft is a tiltrotor configured for frequent (e.g., more than 50 flights per working day), short-duration flights (e.g., less than 100 miles per flight) over, into, and outside densely populated areas. An aircraft may be configured to carry 4 to 6 passengers or commuters expecting a comfortable experience with low noise and low vibration. Therefore, it is desirable to control aircraft components in a manner that reduces aircraft vibration.

[0013] The disclosed embodiments provide novel and improved aircraft component configurations and / or identified design criteria that differ from those of conventional aircraft components, which are not found in conventional aircraft. Such alternative configurations and design criteria, combined to address the shortcomings and challenges associated with conventional components, have led to the embodiments disclosed herein for various configurations and designs of components for aircraft driven by electric propulsion systems (e.g., electric aircraft or hybrid electric aircraft).

[0014] In some embodiments, an aircraft powered by the electric propulsion system of the present disclosure may be designed to be capable of both vertical and conventional takeoff and landing, with a distributed electric propulsion system that enables vertical, horizontal, and lateral flight, as well as transitions (e.g., transitions between vertical and horizontal flight). The aircraft may generate thrust by supplying high-voltage power to multiple engines of the distributed electric propulsion system, and the multiple engines may include components for converting the high-voltage power into mechanical shaft power for rotating propellers.

[0015] Embodiments may include an electric engine connected to an onboard power source, which may include a device capable of storing energy such as a battery or capacitor, and optionally include one or more systems for utilizing or generating electricity, such as a fuel-powered generator or a solar panel array. In some embodiments, the aircraft may include a hybrid aircraft that uses at least one of an electric-based energy source or a fuel-based energy source to power a distributed propulsion system. In some embodiments, the aircraft may be powered by one or more batteries, internal combustion engines (ICE), generators, turbine engines, or ducted fans.

[0016] The engines may be mounted directly to the wing or to one or more booms attached to the wing. The amount of thrust generated by each engine may be controlled by torque commands from the flight control system (FCS) via a digital communication interface to each engine. Embodiments may include forward-facing engines (and associated propellers) that can change their orientation or tilt.

[0017] The engine can also rotate the propeller clockwise or counterclockwise. In some embodiments, the difference in propeller rotation direction can be achieved using the engine rotation direction. In other embodiments, the engines may all rotate in the same direction, and gearing may be used to achieve different propeller rotation directions.

[0018] In some embodiments, an aircraft may have a number of engines in various combinations of forward-engine and rear-engine configurations. Forward-engine engines may be thought of as engines primarily located near the leading edge of the wing. Rear-engine engines may be thought of as engines primarily located near the trailing edge of the wing. For example, an aircraft may have any other combination of forward-engine and rear-engine configurations, including six forward-engine and six rear-engine configurations, five forward-engine and five rear-engine configurations, four forward-engine and four rear-engine configurations, three forward-engine and three rear-engine configurations, two forward-engine and two rear-engine configurations, or embodiments in which the number of forward-engine and rear-engine configurations are not equal.

[0019] In some embodiments, for vertical takeoff and landing (VTOL) missions, the forward and aft engines may provide vertical thrust during takeoff and landing. During the forward flight phase, the forward engine may provide horizontal thrust, while the aft engine's propeller may be retracted to a fixed position to minimize drag. The aft engine may be actively retracted while maintaining positional monitoring.

[0020] Transitions from vertical to horizontal flight and vice versa can be achieved via a tilt propeller subsystem. The tilt propeller subsystem can change the direction of thrust between a primarily vertical direction during the vertical flight phase (e.g., the hovering phase) and a horizontal or nearly horizontal direction during the forward flight cruising phase, based on the tilt of one or more propellers (e.g., determining the orientation of one or more propellers). A variable pitch mechanism can change the collective angle of the blades of the forward engine's propeller hub assembly for operation during flight phases such as the hovering phase, transition phase, and cruising phase. Vertical lift can be primarily vertical thrust (e.g., during the hovering phase). Horizontal thrust can be primarily horizontal thrust (e.g., during the cruising phase).

[0021] In some embodiments, in conventional take-off and landing (CTOL) missions, the forward engines may provide horizontal thrust for fixed-wing take-off, cruising, and landing, while the wings may provide vertical lift. In some embodiments, the rear engines may not be used to generate thrust during CTOL missions, and the rear propellers may be retracted into a fixed position. In other embodiments, the rear engines may be used at reduced power to shorten the length of CTOL take-off or landing.

[0022] As detailed above, an aircraft embodiment may include many movable structural flight elements that enable the pilot to safely control the aircraft. Control of the rotation and orientation of the lift and tilt propellers provides the lift necessary for vertical takeoff and landing and hovering. Furthermore, the rotation and orientation of the tilt propellers provides the forward thrust required to move the aircraft in the air. Thus, propellers are crucial to the controllability, safety, and stability of the aircraft. One or more propellers experiencing significant vibration can jeopardize the safety and stability of the aircraft, as propellers may not respond as commanded. Moreover, vibration can cause measurement errors and lead to structural fatigue and damage to aircraft components.

[0023] The disclosed embodiments control aircraft propellers to reduce vibration response in the aircraft and / or propellers. For example, the disclosed embodiments control aircraft propellers to avoid multiple propellers rotating at the same speed, instead of existing control approaches that control multiple propellers at the same speed (which results in increased vibration). Furthermore, the disclosed embodiments control aircraft propellers to avoid specific speeds where vibration is more severe, instead of existing control approaches that control the propellers regardless of the speed range that causes more severe vibration (which results in increased vibration). The disclosed embodiments can avoid enhanced vibration response in the aircraft and / or propellers (e.g., dangerous vibration, undesirable vibration, avoidable vibration, vibration exceeding a given threshold).

[0024] Herein, exemplary embodiments are given in detail, and examples are illustrated in the accompanying drawings. The following description is given with reference to the accompanying drawings, and unless otherwise specified, the same reference numerals in different drawings represent the same or similar elements. The implementations described below in the exemplary embodiments do not represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with embodiments relating to the subject matter described in the accompanying claims.

[0025] Figure 1 is an illustrative perspective view of an exemplary VTOL aircraft consistent with the disclosed embodiments. Figure 2 is another illustrative perspective view of an exemplary VTOL aircraft in an alternative configuration consistent with embodiments of the present disclosure. Figures 1 and 2 illustrate VTOL aircraft 100, 200 in a cruising configuration and a vertical takeoff, landing, and hovering configuration (also referred to herein as a “lift” configuration), respectively, consistent with embodiments of the present disclosure. Elements corresponding to Figures 1 and 2 have similar figures and can refer to similar elements of aircraft 100, 200. Aircraft 100, 200 may include fuselages 102, 202, wings 104, 204 mounted on the fuselages 102, 202, and one or more rear stabilizers 106, 206 mounted on the rear of the fuselages 102, 202. Multiple lift propellers 112, 212 may be mounted on wings 104, 204 and configured to provide lift for vertical takeoff, landing, and hovering. Multiple tilt propellers 114, 214 may be mounted on wings 104, 204 and may be tiltable (for example, configured to tilt or change orientation) between a lift configuration, as shown in Figure 2, in which these tilt propellers provide a portion of the lift required for vertical takeoff, landing, and hovering, and a cruising configuration, as shown in Figure 1, in which these tilt propellers provide forward thrust to the aircraft 100 for horizontal flight. As used herein, the lift configuration of a tilt propeller refers to any tilt propeller orientation in which the tilt propeller thrust primarily provides lift to the aircraft, and the cruising configuration of a tilt propeller refers to any tilt propeller orientation in which the tilt propeller thrust primarily provides forward thrust to the aircraft.

[0026] In some embodiments, the lift propellers 112, 212 may be configured to provide only lift, with all horizontal thrust provided by the tilt propellers. For example, the lift propellers 112, 212 may be configured in a fixed position and may generate thrust only during the takeoff, landing, and hovering phases of flight. On the other hand, the tilt propellers 114, 214 may be tilted upward in a lift configuration in which the thrust from the propellers 114, 214 is directed downward to provide additional lift.

[0027] For forward flight, the tilt propellers 114, 214 can be tilted from a lift configuration to a cruising configuration. In other words, the orientation of the tilt propellers 114, 214 can change from an orientation in which the thrust of the tilt propellers is directed downward (to provide lift during vertical takeoff, landing, and hovering) to an orientation in which the thrust of the tilt propellers is directed aft (to provide forward thrust to the aircraft 100, 200). The tilt propeller assembly for a particular electric engine can be tilted about an axis of rotation defined by the mounting point connecting the boom and the electric engine. When the aircraft 100, 200 is in full forward flight, lift can be provided entirely by the wings 104, 204. On the other hand, in the cruising configuration, the lift propellers 112, 212 can be shut off. The blades 120, 220 of the lift propellers 112, 212 can be held in a low-drag position for aircraft cruising. In some embodiments, each of the lift propellers 112, 212 may have two blades 120, 220 that can be locked in a minimum-drag position where one blade is directly in front of the other while the aircraft is cruising, as illustrated, for example, in Figure 1. In some embodiments, the lift propellers 112, 212 may have three or more blades. In some embodiments, the tilt propellers 114, 214 may include more blades 116, 216 than the lift propellers 112, 212. For example, as illustrated in Figures 1 and 2, each of the lift propellers 112, 212 may include, for example, two blades, while each of the tilt propellers 114, 214 may include more blades, such as the five blades shown. In some embodiments, each of the tilt propellers 114, 214 may have 2 to 5 blades, and possibly more, depending on the design considerations and requirements of the aircraft.

[0028] In some embodiments, the aircraft may include a single wing 104, 204 on each side of the fuselage 102, 202 (or a single wing extending over the entire aircraft). At least a portion of the lift propellers 112, 212 may be located behind the wings 104, 204 (e.g., the propeller rotation point is behind the wing from a bird's-eye view), and at least a portion of the tilt propellers 114, 214 may be located in front of the wings 104, 204 (e.g., the propeller rotation point is in front of the wing from a bird's-eye view). In some embodiments, all of the lift propellers 112, 212 may be located behind the wings 104, 204, and all of the tilt propellers 114, 214 may be located in front of the wings 104, 204. According to some embodiments, all lift propellers 112, 212 and tilt propellers 114, 214 may be mounted on the wings, i.e., the lift propellers or tilt propellers may not be mounted on the fuselage. In some embodiments, all lift propellers 112, 212 may be located behind the wings 104, 204, and all tilt propellers 114, 214 may be located in front of the wings 104, 204. According to some embodiments, all lift propellers 112, 212 and tilt propellers 114, 214 may be located inside the edges of the wings 104, 204.

[0029] In some embodiments, lift propellers 112, 212 and tilt propellers 114, 214 may be mounted on the wings 104, 204 by booms 122, 222. Booms 122, 222 may be mounted below, above, and / or incorporated into the wing profile. In some embodiments, lift propellers 112, 212 and tilt propellers 114, 214 may be mounted directly on the wings 104, 204. In some embodiments, one lift propeller 112, 212 and one tilt propeller 114, 214 may be mounted on each boom 122, 222. Lift propellers 112, 212 may be mounted at the rear end of booms 122, 222, and tilt propellers 114, 214 may be mounted at the front end of booms 122, 222. In some embodiments, lift propellers 112, 212 may be mounted in fixed positions on booms 122, 222. In some embodiments, tilt propellers 114, 214 may be mounted to the front end of booms 122, 222 via hinges. The tilt propellers 114, 214 may be mounted on booms 122, 222 such that when in their cruising configuration, the tilt propellers 114, 214 are aligned with the body of booms 122, 222, forming a continuous extension of the front end of booms 122, 222 that minimizes drag for forward flight.

[0030] In some embodiments, the aircraft 100, 200 may include, for example, one wing on each side of the fuselage 102, 202, or a single wing extending across the entire aircraft. According to some embodiments, at least one wing 104, 204 is a high wing mounted on the upper side of the fuselage 102, 202. According to some embodiments, the wing includes control surfaces such as flaps and / or ailerons. According to some embodiments, the wings 104, 204 may have a profile that reduces drag during forward flight. In some embodiments, the wingtip profile may be curved and / or tapered to minimize drag.

[0031] In some embodiments, the 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 preferred design to provide lift, directionality, stability, and / or any other properties beneficial to the aircraft. In some embodiments, the wing has a tapered leading edge.

[0032] In some embodiments, the lift propellers 112, 212 or tilt propellers 114, 214 may be tilted relative to at least one other lift propeller 112, 212 or tilt propeller 114, 214, where tilt refers to the relative orientation of the axis of rotation of the lift propeller / tilt propeller around a line parallel to the longitudinal direction, similar to the roll degrees of freedom of an aircraft.

[0033] In some embodiments, one or more lift propellers 112, 212 and / or tilt propellers 114, 214 may be tilted relative to the aircraft cabin such that the axis of rotation of the propellers in the lift configuration is angled away from an axis perpendicular to the upper surface of the aircraft. For example, in some embodiments, the aircraft is a flying wing aircraft as shown in Figure 9E below, and some or all of the propellers are tilted away from the cabin.

[0034] Figure 3 is an illustrative top view of an exemplary VTOL aircraft consistent with embodiments of the present disclosure. The aircraft 300 shown in the figure may be a top view of aircraft 100, 200 shown in Figures 1 and 2, respectively. As previously stated herein, the aircraft 300 may include 12 electric propulsion systems spread out over the aircraft 300. In some embodiments, the distribution of electric propulsion systems may include six forward electric propulsion systems 314 and six rear electric propulsion systems 312 mounted on the forward and rear booms of the main wing 304 of the aircraft 300. In some embodiments, the length of the trailing end of the boom 324 from the wing 304 to the lift propeller (part of the electric propulsion system 312) may include similar trailing ends of the boom 324 across a number of trailing ends of the boom. In some embodiments, the length of the trailing end of the boom may vary, for example, across six trailing ends. Furthermore, Figure 3 illustrates an exemplary embodiment of a VTOL aircraft 300, which has forward propellers (part of the electric propulsion system 314) oriented horizontally for horizontal flight and rear propeller blades 320 in a retracted position for forward flight.

[0035] Figure 4 is a schematic diagram illustrating exemplary propeller rotation of a VTOL aircraft, consistent with the disclosed embodiments. The aircraft 400 shown in the figure may be a top view of aircraft 100, 200, and 300 shown in Figures 1, 2, and 3, respectively. In aircraft 400, three of the forward electric propulsion systems are of the clockwise (CW) type, and the remaining three forward electric propulsion systems are of the counterclockwise (CCW) type. 426This may include six forward electric propulsion systems. In some embodiments, three rearward electric propulsion systems may be CCW type 428, and the remaining three rearward electric propulsion systems may be CW type 430. Some embodiments may include an aircraft 400 having four forward electric propulsion systems and four rearward electric propulsion systems, each having two CW type and two CCW type. In some embodiments, propellers may be reversed relative to adjacent propellers to cancel torque steer generated by the rotation of the propellers and experienced by the fuselage or wings of the aircraft. In some embodiments, the difference in rotation direction may be achieved using the engine rotation direction. In other embodiments, the engines may all rotate in the same direction, and gearing may be used to achieve different propeller rotation directions.

[0036] Some embodiments may include an aircraft 400 having a forward electric propulsion system and a rear electric propulsion system, where the quantities of CW type 424 and CCW type 426 are not equal between forward electric propulsion systems, between rear electric propulsion systems, or between forward electric propulsion systems and rear electric propulsion systems.

[0037] Figure 5 is a schematic diagram illustrating an exemplary power connection in a VTOL aircraft, consistent with the disclosed embodiments. A VTOL aircraft may have multiple power systems connected to diagonally opposed electric propulsion systems. In some embodiments, the power systems may include high-voltage power systems. In some embodiments, high-voltage power systems may be connected to electric engines via high-voltage channels. In some embodiments, the aircraft 500 may include six power systems (e.g., battery packs) including power systems (e.g., battery packs) 526, 528, 530, 532, 534, and 536 housed within the wings 570 of the aircraft 500. The power systems may power the electric propulsion systems and / or other electrical components of the aircraft 500. In some embodiments, the aircraft 500 may include six forward electric propulsion systems having six electric engines 502, 504, 506, 508, 510, and 512, and six rear electric propulsion systems having six electric engines 514, 516, 518, 520, 522, and 524. In some embodiments, one or more power systems (e.g., battery packs) may include a battery management system ("BMS") (e.g., one BMS for each battery pack). Although six power systems are shown in Figure 5, the aircraft 500 may include any number and / or configuration of power systems.

[0038] In some embodiments, one or more battery management systems may communicate with the aircraft's flight control system ("FCS") (e.g., FCS612 shown in Figure 6). For example, the FCS may provide commands to one or more battery management systems to monitor the status of one or more battery packs and / or make adjustments corresponding to high-voltage power supplies. As described above, high-frequency commands can increase power consumption. In some embodiments, as shown in Figure 5, this power consumption can deplete battery packs connected to multiple electric engines. Therefore, there is a need to control the aircraft in a manner that avoids high-frequency commands.

[0039] Figure 6 is a schematic block diagram of an exemplary architecture and design of the electric propulsion power and control system 600 consistent with the disclosed embodiments. The electric propulsion power and control system 600 includes an electric propulsion system 602 which may be configured to control an aircraft propeller. The electric propulsion system 602 may include an electric engine subsystem 604 which may supply torque to a propeller subsystem 606 via a shaft to generate thrust for the electric propulsion system 602. In some embodiments, the electric engine subsystem 604 may include receiving low-voltage direct current (LV DC) power from a low-voltage grid (LVS) 608. In some embodiments, the electric engine subsystem 604 may be configured to receive high-voltage (HV) power from a high-voltage power grid (HVPS) 610 which includes at least one battery or other device capable of storing energy. HV power may refer to power with a voltage lower than the voltage provided by the low-voltage grid (LVS) 608.

[0040] Some embodiments may include an electric propulsion system 602 that includes an electric engine subsystem 604 that receives signals from and transmits signals to the flight control system 612. In some embodiments, the flight control system (FCS) 612 may include a flight control computer that can transmit commands to and receive status and data from the electric engine subsystem 604 using Controller Area Network ("CAN") data bus signals. While the CAN data bus signals are used between the flight control computer and the electric engine(s), it should be understood that some embodiments may include any form of communication that has the ability to send and receive data from the flight control computer to and from the electric engine(s). Some embodiments may include an electric engine subsystem 604 that can receive operating parameters from the FCC in the FCS 612, including speed, voltage, current, torque, temperature, vibration, propeller position, and / or any other values ​​of operating parameters, and transmit the operating parameters to the FCC.

[0041] In some embodiments, the flight control system 612 may also include a tilt propeller system ("TPS") 614 capable of sending and receiving analog and discrete data to and from the electric engine subsystem 604 of the tilt propeller. The tilt propeller system 614 may include a device that transmits operating parameters to the electric engine subsystem 604 and articulates the orientation of the propeller subsystem 606, thereby redirecting the thrust of the tilt propeller during various phases of flight using mechanical means such as a gearbox assembly, linear actuators, and any other configuration of components for changing the orientation of the propeller subsystem 606. In some embodiments, the electric engine subsystem may transmit the orientation of the propeller system (e.g., the angle between lift and forward thrust) to the TPS 614 and / or FCS 612 (e.g., during flight).

[0042] In some embodiments, the flight control system may include a system capable of controlling a control surface and actuators associated with the control surface in an exemplary VTOL aircraft. Figure 7 is an illustrative top view of an exemplary VTOL aircraft consistent with embodiments of the present disclosure. The aircraft 700 shown in the figure may be a top view of aircraft 100 and 200 shown in Figures 1 and 2, respectively. In aircraft 700, the control surface may include a flaperon 712 and a rudder-vator 714 in addition to the propeller blades described above. The flaperon 712 may combine the functions of one or more flaps, one or more ailerons, and / or one or more spoilers. The rudder-vator 714 may combine the functions of one or more rudders and / or one or more elevators. Additionally or alternatively, the control surface may include separate rudders and elevators. In aircraft 700, the actuators may include a control surface actuator (CSA) associated with the flaperon 712 and the rudder-vator 714 in addition to the electric propulsion system described above, as further described below with reference to Figure 8.

[0043] Figure 8 is a schematic example of a flight control signaling architecture 800 for controlling control surfaces and associated actuators, consistent with the disclosed embodiments. Figure 7 illustrates 12 EPU inverters and associated propeller blades, 6 tilt propeller actuators (TPACs), 6 battery management systems (BMSs), 4 flaperons and associated control surface actuators (CSAs), and 6 rudder swivels and associated CSAs, but aircraft according to various embodiments may have any preferred number of these various elements. As shown in Figure 8, the control surfaces and actuators are located on the left FCC, lane A (L FCC-A) 801, left FCC, lane B (L FCC-B) 802, right FCC, lane A (R FCC-A) 803, and right FCC, lane B The (R FCC-B)804 can be controlled by a combination of four flight control computers (FCCs), but any other suitable number of FCCs may be used. Each FCC may control all control planes and actuators individually or in any combination of them. In some embodiments, each FCC may include one or more hardware computing processors. In some embodiments, each FCC may utilize a single-threaded or multi-threaded computing process to perform the calculations required to control the control planes and actuators. In some embodiments, all computing processes required to control the control planes and actuators may be performed by a single flight control computer on a single computing thread.

[0044] The FCC may provide control signals to control surface actuators, including the EPU inverter 806, TPAC 808, BMS 809, flaperon CSA 810, and rudder vater CSA 811, via one or more bus systems. For different control surface actuators, the FCC may provide control signals such as voltage control signals or current control signals, and the control information may be encoded into binary, digital, or analog control signals. In some embodiments, each bus system may be a CAN bus system, e.g., left CAN bus 1, left CAN bus 2, right CAN bus 1, right CAN bus 2, center CAN bus 1, center CAN bus 2 (see Figure 8). In some embodiments, multiple FCCs may be configured to provide control signals via each CAN bus system, and each FCC may be configured to provide control signals via multiple CAN bus systems. In the exemplary architecture illustrated in Figure 8, for example, L FCC-A may provide control signals via left CAN bus 1 and right CAN bus 1, L FCC-B may provide control signals via left CAN bus 1 and central CAN bus 1, R FCC-A may provide control signals via central CAN bus 2 and right CAN bus 2, and R FCC-B may provide control signals via left CAN bus 2 and right CAN bus 2.

[0045] Figures 9A–9E are illustrative top views of an exemplary VTOL aircraft consistent with embodiments of the present disclosure. There may be several design considerations (such as cost, weight, size, and performance capabilities) that may affect the number and / or combination of tilt and lift propellers in a VTOL aircraft. As further described below, the number and orientation of the propellers may affect propeller vibration. Thus, the flight control system may control the propellers in a particular way (e.g., as described in the disclosed embodiments) to reduce the vibration response in the aircraft.

[0046] Figure 9A illustrates an arrangement of the electric propulsion system 900 consistent with embodiments of the present disclosure. Referring to Figure 9A, the aircraft shown in the figure may be a top view of an exemplary aircraft (e.g., a VTOL aircraft). The aircraft may include 12 electric propulsion systems spread out over the aircraft. In some embodiments, the distribution of electric propulsion systems may include six forward electric propulsion systems 901, 902, 903, 904, 905, 906 and six rear electric propulsion systems 907, 908, 909, 910, 911, 912. In some embodiments, the six forward electric propulsion systems may be operably connected to tilt propellers, and the six rear electric propulsion systems may be operably connected to lift propellers. In other embodiments, the six forward electric propulsion systems and some rear electric propulsion systems may be operably connected to tilt propellers, and the remaining rear electric propulsion systems may be operably connected to lift propellers. In other embodiments, all forward and rear electric propulsion systems may be operably coupled to a tilt propeller.

[0047] Figure 9B illustrates an alternative arrangement of the electric propulsion system 940 consistent with embodiments of the present disclosure. Referring to Figure 9B, the aircraft shown in the figure may be a top view of an exemplary aircraft (e.g., a VTOL aircraft). The aircraft may include eight electric propulsion systems distributed across the aircraft. In some embodiments, the distribution of electric propulsion systems may include four forward electric propulsion systems 913, 914, 915, 916 and four rear electric propulsion systems 917, 918, 919, 920. In some embodiments, the four forward electric propulsion systems may be operably connected to tilt propellers, and the four rear electric propulsion systems may be operably connected to lift propellers. In other embodiments, the four forward electric propulsion systems and some rear electric propulsion systems may be operably connected to tilt propellers, and the remaining rear electric propulsion systems may be operably connected to lift propellers. In other embodiments, all forward and rear electric propulsion systems may be operably coupled to tilt propellers.

[0048] Figure 9C illustrates an alternative arrangement of the electric propulsion system 950 consistent with embodiments of the present disclosure. Referring to Figure 9C, the aircraft shown in the figure may be a top view of an exemplary aircraft (e.g., a VTOL aircraft). The aircraft may include six electric propulsion systems distributed across the aircraft. In some embodiments, the distribution of electric propulsion systems may include a first set of four electric propulsion systems 921, 922, 923, and 924 coplanar in a first plane, and a second set of two electric propulsion systems 925 and 926 coplanar in a second plane. In some embodiments, the first set of electric propulsion systems 921-924 may be operably connected to tilt propellers, and the second set of electric propulsion systems 925 and 926 may be operably connected to lift propellers. In other embodiments, the first set of electric propulsion systems 921-924 and the second set of rear electric propulsion systems 925, 926 can all be operably connected to a tilt propeller.

[0049] Figure 9D illustrates an alternative arrangement of the electric propulsion system 960 consistent with embodiments of the present disclosure. Referring to Figure 9D, the aircraft shown in the figure may be a top view of an exemplary aircraft (e.g., a VTOL aircraft). The aircraft may include four electric propulsion systems spread out over the aircraft. In some embodiments, the distribution of electric propulsion systems may include four coplanar electric propulsion systems 927, 928, 929, and 930. In some embodiments, all of the electric propulsion systems may be operably connected to a tilt propeller.

[0050] Figure 9E illustrates an alternative arrangement of the electric propulsion system 970 consistent with embodiments of the present disclosure. Referring to Figure 9E, the aircraft shown in the figure may be a top view of an exemplary aircraft (e.g., a VTOL aircraft). The aircraft may include six electric propulsion systems spread out over the aircraft. For example, in some embodiments, the aircraft may include four forward electric propulsion systems 931, 932, 933, and 934 operably connected to a tilt propeller and two rear electric propulsion systems 935 and 936 operably connected to a lift propeller. In some embodiments, the aircraft may include ten electric propulsion systems spread out over the aircraft. For example, in some embodiments, the aircraft may include six forward electric propulsion systems operably connected to a tilt propeller and four rear electric propulsion systems operably connected to a lift propeller. In some embodiments, some or all of the rear electric propulsion systems may be operably connected to a tilt propeller.

[0051] As shown in Figure 9E, in some embodiments, the aircraft may have an all-wing configuration, such as a tailless fixed-wing aircraft without a distinct fuselage. In some embodiments, the aircraft may have an all-wing configuration in which the fuselage is integrated into the wings. In some embodiments, the tilt propeller may rotate in a plane above the aircraft body when the tilt propeller is operating in a lift configuration.

[0052] As disclosed herein, forward and rear electric propulsion systems may be of the clockwise (CW) or counterclockwise (CCW) type. Some embodiments may include a variety of forward electric propulsion systems having a mixture of both CW and CCW types. In some embodiments, the rear electric propulsion system may have a mixture of CW and CCW type systems among the rear electric propulsion systems. In some embodiments, each electric propulsion system may be fixed as either clockwise (CW) or counterclockwise (CCW) type, while in other embodiments, one or more electric propulsion systems may vary between clockwise (CW) and counterclockwise (CCW) rotation.

[0053] Figure 10 illustrates a functional block diagram of an exemplary aircraft control system 1000 consistent with the disclosed embodiments. System 1000 may be implemented by at least one processor (e.g., at least one microprocessor-based controller) configured to execute software code stored in a storage medium (e.g., computer-readable medium, non-temporary computer-readable medium) to implement the functions described herein. System 1000 may also be implemented in hardware, or in a combination of hardware and software. System 1000 may be implemented as part of an aircraft flight control system (e.g., part of FCS612 in Figure 6) and may be configured to repeatedly perform a single step or a series of steps until a desired or commanded result is obtained. It should be understood that many conventional functions of control systems are not shown in Figure 10 for the sake of clarity. System 1000 further includes one or more storage media storing models, functions, tables, and / or arbitrary information for performing the disclosed processes. As further described below, any box or each box representing the command models 1004, 1006, 1008, 1010, feedback 1012, 1016, 1018, 1022, feedforward 1014, 1020, outer loop assignments 1024, 1026, inner loop control law 1028, control assignment 1029, and vibration damping 1033 may represent or contain modules, scripts, functions, applications, and / or programs executed by the processor(s) and / or microprocessors(s) of system 1000. The complexity and interconnectivity of the functional block diagram in Figure 10 are understood to be impossible, or at least impractical, to be effectively implemented by a human user, especially considering that these functionalities will be implemented during aircraft flight (including takeoff or landing).

[0054] System 1000 may receive at least one pilot input and detect one or more inputs from pilot input devices configured to generate or influence signals. Pilot inputs may be generated by and / or received from aircraft input devices or mechanisms, such as buttons, switches, sticks, sliders, interceptors, or any other devices configured to generate or influence signals based on physical actions from the pilot. For example, pilot input devices may include one or more right interceptors (e.g., activating left / right 1002a and / or forward / backward 1002e), one or more left interceptors (e.g., activating left / right 1002c and / or forward / backward 1002g), and / or left interceptor switches 1002f. In some embodiments, the pilot input device may include an interface with the autopilot system (e.g., display screens, switches, buttons, levers, and / or other interfaces). Optionally, system 1000 may further detect inputs from the autopilot system, such as autopilot roll commands 1002b, autopilot climb commands 1002d, and / or other commands for controlling the aircraft.

[0055] In some embodiments, one or more inputs may include at least one of the following: position and / or rate of the right inceptor and / or left inceptor; signals received from switches on the inceptor (e.g., response type change command, trim input, backup control input, etc.); measured aircraft status and environmental conditions based on data received from one or more sensors of the aircraft (e.g., measured load factor, airspeed, roll angle, pitch angle, actuator status, battery status, aerodynamic parameters, temperature, gust, etc.); obstacles (e.g., presence or absence of other aircraft and / or debris); and aircraft mode (e.g., taxiing on the ground, takeoff, airborne). For example, right inceptor L / R1002a may include the lateral position and / or rate of the right inceptor (e.g., an inceptor positioned to the right of another inceptor, and / or an inceptor positioned to the right of the pilot area), autopilot roll cmd1002b may include the roll signal received in autopilot mode, left inceptor L / R1002c may include the left inceptor (e.g., an inceptor positioned to the left of another inceptor, and / or an inceptor positioned to the left of the pilot area) The autopilot climb cmd1002d may include the lateral position and / or rate of the attached inceptor, the right inceptor F / A1002e may include the climb signal received in autopilot mode, the left inceptor switch 1002f may include the signal from the switch for enabling or disabling the automatic transition function 1003, and the left inceptor F / A1002g may include the lateral position and / or rate of the left inceptor.

[0056] Each input may include additional data such as those listed above (e.g., signals from switches, aircraft status measurements, aircraft mode, etc.). Actuator status may include hardware limitations of the actuator, such as movement limits, speed limits, and response time limits, and may include actuator health indicators that may indicate degradation of actuator performance, which may limit the ability of a given actuator to satisfy actuator commands. Actuator status may be used to determine boundaries (e.g., minimum / maximum) for individual actuator commands. Battery status may correspond to the remaining energy of the aircraft's battery pack and may be monitored when control assignment 1029 considers the balance of the battery pack's energy state. Aerodynamic parameters may be parameters derived from aerodynamic and acoustic modeling and may be based on the actuator's Jacobian matrix and actuator status. Each input received from the interceptor may indicate the corresponding adjustment of the aircraft's heading or power output.

[0057] Command models 1004, 1006, 1008, and 1010 may be configured to determine the shape of an ideal aircraft response (e.g., aggression, slew rate, damping, overshoot, etc.). For example, each of command models 1004, 1006, 1008, and 1010 may be configured to receive and interpret at least one of the inputs 1002a, 1002b, 1002c, 1002d, 1002e, 1002f, and 1002g, and in response to it, calculate the corresponding changes in the aircraft orientation, heading, and thrust, or combinations thereof, using an integrator (not shown). In some embodiments, the right inceptor L / R1002a and autopilot roll cmd1002b may be supplied to the turn rate command model 1004, the left inceptor L / R1002c may be supplied to the lateral speed command model 1006, the autopilot climb cmd1002d and right inceptor F / A1002e may be supplied to the climb command model 1008, and the left inceptor F / A1002g may be supplied to the forward speed command model 1010. In some embodiments, the output from the automatic transition function 1003 may be supplied to at least one of the climb command model 1008 or the forward speed command model 1010. For example, based on receiving an enable signal from the left inceptor switch 1002f, the automatic transition function 1003 may automatically determine at least one of a climb signal or a forward speed signal to transmit to at least one of the climb command model 1008 or the forward speed command model 1010.

[0058] The turn rate command model 1004 may be configured to output a desired position and / or turn rate command, and may also be configured to calculate a desired heading of the aircraft assumed when the interceptor is returned to the center position (i.e., detent). The lateral velocity command model 1006 may be configured to output a desired position and / or lateral velocity command. The climb command model 1008 may be configured to output at least one of a desired altitude command, a vertical velocity command, or a vertical acceleration command. The forward velocity command model 1010 may be configured to output at least one of a desired position, longitudinal velocity, or longitudinal acceleration command. In some embodiments, one or more of the command models may be configured to output accelerations generated in response to changes in velocity commands. For example, the climb command model 1008 may be configured to output vertical accelerations generated in response to changes in vertical velocity commands.

[0059] Feedforwards 1014 and 1020 may each receive as input one or more desired changes from corresponding command models 1004, 1006, 1008, and 1010 (e.g., desired position, velocity, and / or acceleration) and data received from one or more aircraft sensors (e.g., airspeed, vehicle orientation, vehicle load factor, measured acceleration, vehicle mass and inertia, air density, altitude, aircraft mode, etc.), and may be configured to output a corresponding force for each desired change to achieve that desired change. In some embodiments, feedforwards 1014 and 1020 may be configured to determine the corresponding force using a simplified model of aircraft dynamics. For example, based on a known (e.g., stored) or determined mass of the aircraft, feedforwards 1014 and 1020 may be configured to determine the force that will cause the aircraft to comply with a desired acceleration command. In some embodiments, feedforwards 1014 and 1020 may be configured to use a model that predicts the amount of drag acting on the vehicle as a function of velocity in order to determine the force required to comply with a desired velocity command signal.

[0060] Feedbacks 1012, 1016, 1018, and 1022 may each receive as input one or more desired changes from command models 1004, 1006, 1008, and 1010 (e.g., desired position, velocity, and / or acceleration), and data received from vehicle detection 1031 indicating vehicle dynamics 1030. For example, detected vehicle dynamics 1030 may include the physical and / or inherent dynamics of an aircraft, and a vehicle Both inspections Sensor measurements from the vehicle detection 1031 can capture how the aircraft moves in response to pilot input, propulsion system output, or ambient conditions. Additionally or alternatively, data received from the vehicle detection 1031 may include error signals generated by one or more processors based on extrinsic disturbances (e.g., velocity disturbances due to gusts). In some embodiments, feedbacks 1012, 1016, 1018, and 1022 may be configured to generate feedback forces (e.g., in actuators) based on received error signals. For example, feedbacks 1012, 1016, 1018, and 1022 may generate feedback forces intended to counteract the effect(s) of external disturbances. Additionally or alternatively, feedbacks 1012, 1016, 1018, and 1022 may be configured to generate feedback forces based on modeling errors. For example, if an incorrect aircraft mass is input to either the feedforward 1014 or 1020, the aircraft may accelerate faster or slower than the desired change. Based on determining the difference between the desired acceleration and the measured acceleration, one or more processors (for example, those included in the vehicle detection 1031) may generate an error signal and loop the error signal to feedback 1012, 1016, 1018, or 1022 to determine the additional force required to correct the error.

[0061] In some embodiments, feedbacks 1012, 1016, 1018, and 1022 can be disabled. For example, system 1000 may be configured to operate without feedbacks 1012, 1016, 1018, and 1022 until GPS communication is reconnected, in response to the loss of position and / or ground velocity feedback due to a disruption of Global Positioning System (GPS) communication.

[0062] In some embodiments, feedbacks 1012, 1016, 1018, and 1022 may receive as input multiple measurements and confidence values ​​for each measurement indicating whether the measurement is valid. For example, one or more processors in system 1000 may assign a Boolean value (true / false) to each measurement used in system 1000 to indicate whether the measurement is reliable (e.g., yes) or invalid (e.g., no). Based on one or more processors identifying a measurement as invalid, feedbacks 1012, 1016, 1018, and 1022 may exclude that measurement for further processing. For example, in response to one or more processors identifying a heading measurement as invalid, feedbacks 1012, 1016, 1018, and 1022 may omit subsequent heading measurements when determining the feedback force(s).

[0063] In some embodiments, feedbacks 1012, 1016, 1018, and 1022 may determine one or more feedback forces based on actuator state information received from one or more sensors (e.g., included in vehicle detection 1031). For example, in response to actuator state information indicating an actuator failure, one or more processors of system 1000 may update one or more processes of system 1000 and determine alternative commands to achieve a desired change. For example, in response to an actuator failure, one or more processors of system 1000 may adjust one or more models, functions, algorithms, tables, inputs, parameters, thresholds, and / or constraints. Alternative commands (e.g., yaw, pitch, roll, thrust, or torque) may be determined based on the adjustment(s). Additionally or alternatively, in response to actuator state information indicating that one or more actuators are at their maximum values, one or more processors of system 1000 may update one or more processes of system 1000 (e.g., as described above) and determine alternative commands to achieve a desired change.

[0064] The total desired force can be calculated based on the outputs of feedback 1012, 1016, 1018, 1022 and feedforward 1014, 1020. For example, one or more processors of system 1000 may calculate the desired rotation force by summing the outputs of feedback 1012 and feedforward 1014. Additionally or alternatively, one or more processors of system 1000 may calculate the desired lateral force by summing the outputs of feedback 1016 and feedforward 1014. Additionally or alternatively, one or more processors of system 1000 may calculate the desired vertical force by summing the outputs of feedback 1018 and feedforward 1020. Additionally or alternatively, one or more processors of system 1000 may calculate the desired longitudinal force by summing the outputs of feedback 1022 and feedforward 1020.

[0065] The lateral / directional outer loop assignment 1024 and the longitudinal outer loop assignment 1026 each provide one or more desired forces and data received from one or more aircraft sensors (e.g., airspeed, vehicle orientation, vehicle load factor, measured acceleration, vehicle mass and inertia, indicators of working / failed actuators, air density, altitude, aircraft mode, whether the aircraft is in flight or on the ground (e.g., whether there is weight on the wheels)). ) They can be configured to receive and as inputs. Based on the inputs, outer loop assignments 1024 and 1026 can be configured to output a roll command, a yaw command, a pitch command, a thrust request, or a combination of different commands / requests in order to achieve one or more desired forces.

[0066] The lateral / directional outer loop assignment 1024 may receive a desired turn rate force and / or a desired lateral force as input and may command roll or yaw. In some embodiments, the lateral / directional outer loop assignment 1024 may determine an output based on a determined flight mode. The flight mode may be determined using pilot input (e.g., a selected mode for the interceptor) and / or detected aircraft information (e.g., airspeed). For example, the lateral / directional outer loop assignment 1024 may determine the aircraft's flight mode using at least one of a determined (e.g., detected or measured) airspeed or an input received at a pilot interceptor button (e.g., an input that instructs the aircraft to fly according to a particular flight mode). In some embodiments, the lateral / directional outer loop assignment 1024 may be configured to prioritize pilot interceptor button input over measured airspeed when determining the flight mode (e.g., pilot interceptor button input(This is associated with a stronger weight or higher priority than the measured airspeed). In some embodiments, the lateral / directional outer loop assignment 1024 may be configured to blend the determined airspeed and pilot interceptor button input (e.g., using weight sum) to determine the aircraft's flight mode. In hovering flight mode, the lateral / directional outer loop assignment 1024 may achieve a desired lateral force with a roll command (e.g., roll angle, roll rate) and a desired turn rate force with a yaw command. In some embodiments, such as in hovering flight mode, the aircraft may be configured not to accelerate outside a given hovering envelope (i.e., hovering speed range). In forward flight mode (e.g., level flight), the lateral / directional outer loop assignment 1024 may achieve a desired lateral force with a yaw command and a desired turn rate force with a roll command. In forward flight mode, the lateral / directional outer loop assignment 1024 may be configured to determine the output based on the detected airspeed. In the transition between hovering flight mode and forward flight mode, the lateral / directional outer loop assignment 1024 can achieve the desired force using a combination of roll and yaw commands.

[0067] The longitudinal outer loop assignment 1026 may receive a desired vertical force and / or a desired longitudinal force as input and may output at least one of a pitch command (i.e., pitch angle) or a thrust vector request. The thrust vector request may include longitudinal thrust (i.e., a mixture of nacelle tilt and forward propeller thrust) and vertical thrust (i.e., a combination of forward thrust and rear thrust). In some embodiments, the longitudinal outer loop assignment 1026 may determine the output based on a determined flight mode. For example, in hovering flight mode, the longitudinal outer loop assignment 1026 may achieve the desired longitudinal force by lowering the pitch attitude and using longitudinal thrust, or by achieving the desired vertical force with vertical thrust. In forward flight mode, the longitudinal outer loop assignment 1026 may achieve the desired longitudinal force with longitudinal thrust (e.g., forward propeller thrust). In cruising flight mode, the longitudinal outer loop allocation The 1026 can achieve a desired vertical force by commanding the pitch (e.g., increasing the pitch attitude) and requesting thrust (e.g., increasing the longitudinal thrust).

[0068] The inner loop control law 1028 may be configured to determine a moment command based on at least one of a roll command, yaw command, or pitch command from a lateral / directional outer loop assignment 1024 or a longitudinal outer loop assignment 1026. In some embodiments, the inner loop control law 1028 may depend on detected vehicle dynamics (e.g., from vehicle detection 1031). For example, the inner loop control law 1028 may be configured to compensate for disturbances at attitude and rate levels to stabilize the aircraft. Additionally or alternatively, the inner loop control law 1028 may take into account the period of eigenmodes affecting the pitch axis (e.g., phugoid modes) and may appropriately control the aircraft to compensate for such eigenmodes of the vehicle. In some embodiments, the inner loop control law 1028 may depend on the inertia of the vehicle.

[0069] The inner-loop control law 1028 may determine moment commands using one or more stored dynamic models that reflect the aircraft's motion characteristics (e.g., aerodynamic damping and / or inertia). In some embodiments, the inner-loop control law 1028 may use a dynamic model (e.g., a low-order equivalent system model) to capture the aircraft's motion characteristics and determine one or more moments that cause the aircraft to achieve commanded roll, yaw, and / or pitch. Some embodiments may include determining moment commands based on at least one received command (e.g., roll command, yaw command, and / or pitch command) and determined (e.g., measured) aircraft state (e.g., by the inner-loop control law 1028 or other components). For example, moment commands may be determined using the difference between the commanded aircraft state and the measured aircraft state. As a further example, moment commands may be determined using the difference between the commanded roll angle and the measured roll angle. As described below, the control assignment 1029 may control the aircraft (e.g., via flight elements) based on the determined moment command(s). For example, control assignment 1029 may control (e.g., transmit one or more commands to) one or more electric propulsion systems of an aircraft (e.g., electric propulsion system 602 shown in Figure 6), including tilt actuators, electric engines, and / or propellers. Control assignment 1029 may further control one or more control surfaces of an aircraft (e.g., control surfaces 712 and 714 shown in Figure 7), including flaperons, rudder swivels, ailerons, spoilers, rudders, and / or elevators. Vehicle dynamics 1030 represent the controlled flight elements (e.g., electric propulsion systems and / or control surfaces) and aircraft dynamics.

[0070] The embodiment shown in Figure 10 includes both the inner-loop control law 1028 and the outer-loop assignments 1024, 1026, although in some embodiments the flight control system may not include the outer-loop assignments 1024, 1026. Thus, pilot inceptor inputs can generate roll commands, yaw commands, pitch commands, and / or thrust commands. For example, the right inceptor may control roll and pitch, and the left inceptor and / or pedal(s) may control yaw and thrust.

[0071] The control assignment 1029 may accept one or more of the following as inputs: force and moment commands, data received from one or more aircraft sensors, envelope protection limits, scheduling parameters, and optimizer parameters. Based on the inputs, the control assignment 1029 may be configured to determine actuator commands (e.g., thrust(s), torque(s), and / or propeller speed for an electric propulsion unit) by minimizing an objective function that includes one or more primary objectives, such as satisfying commanded aircraft forces and moments, and one or more secondary objectives, which may include minimizing acoustic noise and / or optimizing battery pack usage.

[0072] In some embodiments, the control assignment 1029 may be configured to calculate limits for individual actuator commands based on the actuator state and envelope protection limits. Under normal operation, the minimum command limit for a given actuator includes the maximum of the hardware-based minimum limit and the flight envelope minimum limit, and the maximum command limit for a given actuator includes the minimum of the hardware-based maximum limit and the flight envelope maximum limit. If an actuator fails, the command limit for the failed actuator will correspond to its failure mode.

[0073] Control assignment 1029 transmits commands to one or more flight elements for controlling the aircraft. The flight elements are configured to move according to the controlled commands. Both inspections Various sensing systems and associated sensors as part of the knowledge 1031 may detect the operation of flight elements and / or the aircraft's dynamics and provide information to the feedback 1012, 1016, 1018, 1022, outer loop assignments 1024, 1026, inner loop control laws 1028, and control assignments 1029 which are incorporated into the flight control.

[0074] As described above, the vehicle detection system 1031 may include one or more sensors for detecting vehicle dynamics. For example, the vehicle detection system 1031 may capture how the aircraft moves in response to pilot input, propulsion system output, or ambient conditions. Additionally or alternatively, the vehicle detection system 1031 may detect errors in the aircraft's response based on extrinsic disturbances (e.g., velocity disturbances due to gusts).

[0075] Furthermore, the vehicle detection system 1031 may include one or more sensors for detecting propeller speed, such as a magnetic sensor (e.g., a Hall effect sensor or induction sensor) or an optical sensor (e.g., a tachometer) for detecting the rotor speed (and therefore the propeller speed) of the aircraft engine. The vehicle detection system 1031 may include one or more sensors for detecting the nacelle tilt angle (e.g., the propeller rotation axis angle between the lift configuration (e.g., Figure 2) and the forward thrust configuration (e.g., Figure 1)). For example, one or more magnetic sensors (e.g., Hall effect or induction sensors), position displacement sensors, linear displacement sensors, and / or other sensors associated with the tilt actuator may detect the tilt angle (e.g., with respect to the aircraft and / or wings) which may be provided to the system 1000. Furthermore, one or more pitot tubes, accelerometers, and / or gyroscopes may detect the pitch angle of the aircraft which may be provided to the system 1000. In some embodiments, the vehicle detection 1031 may combine tilt angle sensor measurements and aircraft pitch measurements to determine the overall nacelle tilt angle of the propeller. The vehicle detection 1031 may include one or more sensors configured to detect engine torque and / or thrust, such as one or more current sensors or voltage sensors, strain gauges, load cells, and / or propeller vibration sensors (e.g., accelerometers).

[0076] The vehicle detection 1031 may include one or more sensors configured to detect vehicle dynamics, such as acceleration sensors and / or pitch orientation sensors (e.g., accelerometers(or more), triaxial accelerometers(or more), gyroscopes(or more), and / or triaxial gyroscopes(or more)) and airspeed sensors (e.g., Pitot tube sensors), and the vehicle detection 1031 may further include one or more inertial measuring units (IMUs) for determining the aircraft state based on these measurements. The aircraft state may refer to forces experienced by the aircraft, the orientation of the aircraft, the position of the aircraft (e.g., altitude), and / or the motion of the aircraft. For example, the aircraft state may include at least one of the following: the aircraft's position (e.g., yaw angle, roll angle, pitch angle, and / or any other orientation across one or two axes), the aircraft's speed, the aircraft's angular rates (e.g., roll rate, pitch rate, and / or yaw rate), and / or the aircraft's acceleration (e.g., longitudinal, lateral, and / or vertical acceleration), or any physical properties of the aircraft or one of its components. In some embodiments, the vehicle detection 1031 may include an inertial navigation system (INS) and / or atmospheric data and / or attitude heading reference system (ADAHRS). The inertial navigation system (INS) and / or atmospheric data and attitude heading reference system (ADAHRS) may include one or more inertial measurement units (IMUs) and corresponding sensors (e.g., accelerometers, gyroscopes, 3-axis gyroscopes, and / or 3-axis accelerometers). In some embodiments, the INS and / or ADAHRS may filter and / or process sensor measurements to determine aircraft conditions (e.g., acceleration or angular rate). For example, in some embodiments, the INS and / or ADAHRS may determine the angular rate based on gyroscope measurements and the acceleration based on accelerometer measurements.

[0077] The vehicle detection system 1031 may include one or more sensors for detecting the flight phase of an aircraft (e.g., the measured state of the aircraft). For example, the vehicle detection system 1031 may include an atmospheric data system and / or atmospheric sensors (e.g., a Pitot tube) for determining the flight phase. GPS This may include sensors, tilt angle sensors, accelerometers, and / or gyroscopes. In some embodiments, the flight phase may be determined based on comparing one or more of these sensor measurements to pre-stored thresholds. For example, vehicle detection 1031 and / or another section of system 1000 (e.g., vibration damping 1033) may determine a flight phase change when the aircraft's airspeed is above a threshold and / or when the aircraft's airspeed is decreasing below a threshold and the propeller tilt angle is below a threshold. Different relationships may be stored and associated with specific flight phases, as described below with reference to Figure 15.

[0078] In some embodiments, the vibration damper 1033 may set one or more hard constraints and / or soft constraints on the control assignment 1029, as further described below. In some embodiments, the vibration damper 1033 may determine, holistically or partially, at least one propeller parameter that may affect (e.g., limit and control) the speed at which one or more propellers of the aircraft may rotate in order to avoid commanding the propellers to rotate at speeds that cause increased vibrations. For example, in some embodiments, the vibration damper 1033 may set as hard constraints one or more ranges of propeller torque and / or corresponding propeller speed that the control assignment 1029 must avoid when commanding the propellers of the aircraft. The torque may correspond to speeds that cause increased (e.g., dangerous, avoidable, or threshold-exceeding) propeller vibrations. In some embodiments, the vibration damping 1033 may set as a hard constraint one or more ranges of propeller torque and / or corresponding propeller speed that the control assignment 1029 must maintain in order to avoid commanding the propeller to rotate at a speed that causes increased (e.g., dangerous, avoidable, or exceeding a threshold) vibrations. In some embodiments, the vibration damping 1033 may set as a soft constraint to avoid propeller speed ranges corresponding to increased (e.g., dangerous, avoidable, or exceeding a threshold) vibrations. For example, the vibration damping 1033 may define one or more attractor parameters (e.g., corresponding to target propeller speed and / or torque) for an optimization function to avoid these propeller torque ranges corresponding to increased propeller vibrations. Thus, the control assignment 1029 is configured to determine a torque command that avoids those regions unless other objectives take precedence.

[0079] As further described below, the vibration damper 1033 may vary the range of propeller torque avoidance based on the propeller condition (e.g., nacelle tilt angle) and the aircraft condition (e.g., airspeed and / or flight phase). In some embodiments, the vibration damper 1033 may receive feedback regarding the propeller speed and adjust the torque command based on identifying that the propeller(s) speed falls within one or more ranges corresponding to the increased vibration.

[0080] In some embodiments, the vibration damping 1033 is used for multiple propellers of Matching propeller speeds (e.g., identical propeller speeds or within a threshold range) To rotate To avoid commanding, at least one propeller parameter can be determined holistically or partially, which may affect (e.g., limit and control) the speed at which one or more propellers of the aircraft may rotate. For example, at least one propeller parameter may represent at least one of the following: the difference in the sum of propeller speeds across all propellers of the aircraft, the difference in propeller speeds between pairs of propellers of the aircraft (e.g., each possible combination of propeller pairs), and / or the corresponding torque required for these speed differences. In some embodiments, vibration damping 1033 may set the difference between propeller speeds as a soft constraint to avoid the amplification of vibrations caused by multiple propellers rotating at the same speed. Thus, control assignment 1029 is configured to determine torque commands corresponding to different speeds unless other objectives take precedence.

[0081] Figure 11 illustrates the effect of vibration on a signal, consistent with the disclosed embodiment. As the propeller rotates, it can generate significant vibrations of multiple frequencies proportional to the propeller's rotational speed. These vibrations 1103 can be transmitted through the engine and aircraft structure to inertial measuring units (IMUs) 1102 (e.g., the IMU and corresponding accelerometers in vehicle detection 1031). The vibrations 1103 can worsen the vehicle state estimates based on IMU measurements, feed through to the flight control system 1101, and result in high-frequency commands to the flight elements 1104. As described above, these high-frequency commands can result in increased power consumption, increased temperatures of aircraft components, increased cycle and wear of aircraft components, increased cabin and community noise, and a reduced ride comfort.

[0082] Figure 12 illustrates a scenario in which vibration may be more severe, consistent with the disclosed embodiments. Vibration may be particularly strong and at more destructive frequencies on two- and three-bladed propellers, such as those used in one or more of the rear propellers or lifter propellers of an aircraft, in some embodiments of this disclosure. Furthermore, vibration may be particularly strong when the propeller is oriented into an airflow along its edges, as shown in 1201, such as when the axis of rotation is perpendicular to the aircraft's trajectory. Vibration may be less strong when the propeller is oriented parallel to the airflow, as shown in 1202, such as when the axis of rotation is parallel to the aircraft's trajectory. Therefore, any aircraft detailed in Figures 9A–9E above, including propellers oriented to experience an airflow along its edges, may be particularly susceptible to propeller vibration. However, any aircraft having propellers may implement this disclosure and would find it beneficial to do so.

[0083] Figure 13 illustrates another scenario in which vibration may be more severe, consistent with the disclosed embodiments. Aircraft vibration can be particularly strong when multiple propellers rotate at the same speed, as represented by waveform 1310a. When the propellers rotate at the same speed, the propeller vibration is cumulative, as indicated by more frequent high signal amplitudes. Aircraft vibration can be less severe when the propellers rotate at different speeds, as represented by waveform 1310b. When the propellers rotate at different speeds, the effect of vibration is not cumulative, as indicated by lower signal amplitudes and less frequent high signal amplitudes.

[0084] Figure 14 illustrates an aircraft control for vibration damping consistent with the disclosed embodiment. As described above, the system 1000 may include at least one processor and at least one memory for receiving pilot inceptor inputs, navigation inputs, sensor information (e.g., reflecting flight dynamics or flight conditions), determining control signals according to aircraft control laws and assignments, and transmitting control signals for controlling flight elements (e.g., control planes, propellers, tilt actuators).

[0085] The vibration damping 1033 may include at least one processor and at least one memory. In some embodiments, the vibration damping 1033 may be part of the system 1000 (e.g., part of the FCC), while in other embodiments, the vibration damping 1033 may be separate.

[0086] The vibration damper 1033 may receive aircraft state estimates and / or sensor data from the vehicle detection 1031. In some embodiments, the vehicle detection 1031 may include one or more sensors for measuring propeller speed(s) (e.g., RPM). For example, the vehicle detection 1031 may include one or more magnetic sensors (e.g., Hall effect or inductive sensors) and / or optical sensors (e.g., tachometers) for determining propeller speed(s). In some embodiments, the vehicle detection 1031 may include one or more sensors for determining atmospheric density (e.g., pressure sensors and temperature sensors(s)).

[0087] In some embodiments, vehicle detection 1031 and / or vibration damping 1033 may determine at least one propeller speed based on the measured airspeed and measured atmospheric density. Vehicle detection 1031 and / or vibration damping 1033 may determine propeller speed(s) based on predetermined propeller speeds and predetermined atmospheric densities at the measured airspeed. For example, propeller speed may be determined based on predetermined propeller speeds and predetermined atmospheric densities at the sea surface for the measured airspeed. The predetermined propeller speeds and predetermined atmospheric densities at the sea surface may be determined before flight by modeling the propeller speeds and / or atmospheric densities at the sea surface at the measured airspeed based on measured values ​​of propeller speed and / or atmospheric densities acquired during flight over the sea surface at the measured airspeed, and / or by determining the propeller speeds and / or atmospheric densities at the sea surface at the measured airspeed using one or more algorithms. For example,

[0088]

number

[0089] In some embodiments, the vehicle detection 1031 may include an inertial navigation system, an inertial measurement unit, and / or inertial sensors (e.g., accelerometer, gyroscope, magnetometer). In some embodiments, the vehicle detection 1031 may include one or more atmospheric velocity sensors (e.g., one or more Pitot tube pressure sensors). In some embodiments, the vehicle detection 1031 may include one or more tilt angle sensors for determining the tilt angle of the propeller, such as a magnetic sensor for determining the tilt angle between a lift configuration (e.g., Figure 2) and a forward thrust configuration (e.g., Figure 1). In some embodiments, the vehicle detection 1031 may include one or more microphones inside and / or on the aircraft.

[0090] The vibration damper 1033 may receive pilot inputs indicating a commanded aircraft state (e.g., from the interceptor), autopilot, and / or inputs from one or more sections of system 1000. For example, in some embodiments, the commanded aircraft state may depend on a command model (e.g., 1004, 1006, 1008, and / or 1010), an outer loop assignment (e.g., 1024 and / or 1026), and / or an inner loop control law (e.g., 1028).

[0091] In some embodiments, as further described below, the vibration damper 1033 may store one or more functions, one or more data tables, and / or one or more models for converting propeller speed to corresponding torque values. For example, the vibration damper 1033 may convert propeller speed to corresponding torque commands based on the flight phase.

[0092] In some embodiments, the vibration damping 1033 may include one or more functions (e.g., implemented in a module, script, application, and / or program) for controlling the propeller rotation speed to reduce propeller vibration and / or noise. In some embodiments, the vibration damping 1033 may include an RPM prohibition function 1033a, and optionally associated data tables and / or models. As further detailed below, the RPM prohibition 1033a may control the torque command to avoid propeller speeds corresponding to increased vibration. In some embodiments, the vibration damping 1033 may include an RPM splitting function 1033b, and optionally associated data tables and / or models. As further detailed below, the RPM splitting 1033b may control the torque command to avoid matching propeller speeds among multiple propellers.

[0093] Based on one or more functions, the vibration damping 1033 may provide one or more inputs to the flight control laws 1453 (e.g., boxes in Figure 10 other than the vibration damping 1033), such as optimizer functions of control assignment 1029. For example, the vibration damping 1033 may provide one or more soft constraints (e.g., flexible, and / or low priority) and / or hard constraints (e.g., inflexible constraint, strict constraint, higher priority constraint) used by control assignment 1029 to determine propeller commands. In some embodiments, these inputs may be specific to each propeller of the aircraft. The flight control laws 1453 (e.g., control assignment 1029) may determine propeller commands (e.g., torque commands) sent to the propellers based on the soft and / or hard constraints. Furthermore, these propeller commands satisfy the constraints(s) In order to This may be determined to cause a commanded aircraft state (e.g., thrust vector and / or moment), thereby avoiding an increase in aircraft vibration.

[0094] In some embodiments, the flight control rule 1453 (e.g., control assignment 1029) may prioritize different constraints. For example, the flight control rule 1453 may prioritize the constraints of maintaining support for lift and / or forward thrust, meeting load requirements (e.g., root loads on the wings), meeting battery requirements, meeting high-voltage power limit requirements, avoiding propeller speed prohibition ranges, meeting engine thermal requirements, and avoiding matching propeller speeds between different propellers (e.g., a specific combination of propellers, two propellers, three or more propellers). In some embodiments, the flight control rule 1453 (e.g., control assignment 1029) may prioritize avoiding propeller speed prohibition ranges (e.g., based on the constraint of RPM prohibition 1033a) over avoiding matching propeller speeds (e.g., based on the constraint of RPM division 1033b). For example, if control assignment 1029 cannot determine how to control the propeller speed to satisfy both constraints, then control assignment 1029 will control the vehicle movement Condition 1 The 030 outputs a signal to one or more EPUs (for example, to rotate each of the 1454 propellers), and the EPU s Each propeller associated with the system is required to satisfy the constraints of the propeller speed prohibition range rather than the constraints of avoiding matching propeller speeds. In some embodiments, as will be further detailed below, the control assignment 1029 may prioritize reducing propeller vibration over reducing noise emissions. For example, if controlling the propeller only to RPM speed(s) that reduce noise emissions has a neutral or positive effect on reducing propeller vibration, the control assignment 1029 may be configured in this manner. Furthermore, even if controlling the propeller only to RPM speed(s) that reduce propeller vibration results in increased noise emissions, the control assignment 1029 may be configured in this manner.

[0095] Figure 15 illustrates an aerodynamic model consistent with the disclosed embodiments. In some embodiments, System 1000, including flight control laws 1453 and / or vibration damping 1033, may store one or more aerodynamic models, which may model conditions of the aircraft and / or aircraft components (e.g., statically or dynamically) based on one or more parameters (e.g., commands, aircraft orientation, aircraft flight phase, battery charge, or measured contextual attributes such as speed, altitude, or crosswind). For example, System 1000, including control assignments 1029, may store models such as the one shown in Figure 15, detailing the relationship between torque, thrust, and propeller speed (e.g., in a storage medium that is part of or separate from control assignments 1029) based on the flight phase. Control assignments 1029 may use these models to determine the required torque command to satisfy commanded thrust and / or propeller speed requirements (e.g., to avoid vibration).

[0096] As described above, in some embodiments, one or more aerodynamic models may correspond to flight phases. One or more models 1550a may represent stored relationships between thrust, torque, and propeller speed when the aircraft is in the hovering phase. One or more models 1550b may represent stored relationships between thrust, torque, and propeller speed when the aircraft is in forward flight conditions. One or more models 1550c may represent stored relationships between thrust, torque, and propeller speed when the aircraft is in different flight phases. System 1000 may store these relationships as functions, models, and / or lookup tables.

[0097] Flight control law 1453, by reference to these relationships, ensures that the aircraft is controlled as commanded (e.g., command determined by inner-loop control law 1028) based on the relationship between thrust and torque. Furthermore, vibration damping 1033, by reference to these relationships, can determine at least one torque command that achieves the required propeller speed variation (e.g., for RPM division 1033b), avoids propeller speeds corresponding to high vibrations (e.g., for RPM prohibition 1033a), and / or does not violate any constraints (e.g., aircraft thrust requirements) based on the relationship between propeller speed, torque, and thrust.

[0098] Although only three flight phases and their corresponding relationships are shown in Figure 15, system 1000 can store any number of relationships corresponding to different flight phases. For example, system 1000 can store relationships based on incremental changes to aircraft speed and / or propeller tilt angle. For example, system 1000 can store different relationships corresponding to changes of 2%, 5%, 10%, etc., in aircraft speed, propeller tilt angle, and / or other conditions affecting the relationships between thrust, torque, and propeller speed. In some embodiments, system 1000 can store models and / or algorithms, where aircraft speed, propeller tilt angle, and / or other conditions can be inputs for determining appropriate relationships between thrust, torque, and propeller speed. 。

[0099] Figures 16A and 16B illustrate exemplary instructions for vibration damping based on avoiding propeller prohibition zones, consistent with the disclosed embodiments. In some embodiments, the RPM prohibition 1033a may determine one or more propeller speed ranges corresponding to enhanced vibrations. In some embodiments, the RPM prohibition 1033a may retrieve at least one propeller parameter associated with propeller speeds that avoid enhanced vibration responses in the aircraft. For example, in some embodiments, the RPM prohibition 1033a may store and retrieve propeller speed prohibition ranges (may be multiple) corresponding to enhanced (e.g., hazardous) vibrations of the aircraft and / or aircraft components (e.g., aircraft body, propeller, boom, wing, etc.) based on experimental data and / or modeling. For example, propeller vibrations (e.g., at N / rev frequencies) may be measured over all propeller speeds the propeller may encounter to determine which propeller speeds generate enhanced vibrations. Increased vibrations may include vibrations exceeding a given threshold, vibrations that distort acceleration measurements, vibrations that cause aircraft stability problems, vibrations that cause engine performance problems, vibrations that cause controllability problems, vibrations that cause structural problems, vibrations that strain one or more aircraft components, vibrations that cause aircraft components to behave outside of given operational limits (e.g., interference limits, strain limits, force limits, etc.), and / or vibrations that are otherwise non-ideal for aircraft operation. Propeller speed ranges corresponding to increased vibrations may be stored as propeller speed prohibited ranges. Propeller speed "prohibited" and "avoided" ranges and / or bands are used interchangeably to refer to propeller speed ranges (e.g., for one or more propellers) corresponding to increased (e.g., dangerous) vibrations.

[0100] In some embodiments, the propeller speed prohibition range(s) may vary based on the airflow along the edge(s), which may be a function of the propeller(s) airspeed, wind conditions, and / or tilt configuration. For example, as shown above in configuration 1201 of Figure 12, the propeller may experience more significant vibrations when in crossflow along the edge(s). Thus, under these conditions, such as when the propeller rotation axis is perpendicular to the aircraft trajectory (e.g., in a lift configuration) and the aircraft's airspeed is higher, the propeller speed prohibition range may be larger. Therefore, the RPM prohibition(s) 1033a may be configured to increase the propeller speed avoidance range based on the aircraft's airspeed and the propeller angle indicating an increase in airflow along the edge(s).

[0101] Therefore, in some embodiments, the RPM prohibition 1033a can dynamically change the propeller speed prohibition band based on airspeed and / or propeller angle. For example, the propeller speed may correspond to the prohibition band when the propeller is in a lift configuration but not when the propeller is in a thrust configuration. In some embodiments, the propeller speed may correspond to the prohibition band at high airspeeds but not at low airspeeds.

[0102] In some embodiments, the RPM prohibit 1033a may store one or more algorithms for adjusting the propeller speed prohibit range(s) based on airspeed and / or propeller angle (e.g., dynamically during flight). In some embodiments, the RPM prohibit 1033a may store one or more tables or models for determining the propeller speed prohibit range(s) based on airspeed and / or propeller angle (flight conditions). In some embodiments, the propeller angle may be measured for each individual propeller, and the propeller speed prohibit range for each propeller may be adjusted based on the respective propeller angle measurement. In some embodiments, the propeller angle measurement may represent or correspond to the angle of a group of propellers (e.g., all forward propellers), and the propeller speed prohibit range for the group of propellers may be adjusted based on the respective propeller angle measurement. In some embodiments, the propeller angle measurement may represent or correspond to the angle of all propellers (e.g., all forward propellers), and the propeller speed prohibition range for all propellers may be adjusted based on the propeller angle measurement. In some embodiments, the RPM prohibition 1033a may correlate the size of the propeller speed prohibition range with at least one of the propeller rotation axis relative to the aircraft trajectory or the aircraft's airspeed. For example, the RPM prohibition 1033a may determine a larger propeller speed prohibition range under certain flight conditions where vibrations are more severe, such as when the propeller rotation axis is perpendicular to the aircraft trajectory (e.g., in a lift configuration) and the airspeed is higher (indicating greater, edge-oriented airflow).

[0103] In some embodiments, the algorithm, table, and / or model of the RPM prohibition 1033a may further include the influence of wind conditions (e.g., configuration 1201 in Figure 12) contributing to the airflow along the edge. In some embodiments, the RPM prohibition 1033a may be adjusted based on the relationship between the propeller speed prohibition range and the torque(s) for a determined flight phase (e.g., using the relationship shown in Figure 15).

[0104] As shown in Figure 16A, in some embodiments, the RPM prohibition 1033a may apply hard constraints on one or more propeller speed prohibition ranges. For example, in some embodiments, the RPM prohibition 1033a may provide at least one range of available torque excluding the torque corresponding to each propeller speed prohibition range(s) for each propeller. Thus, the flight control law (e.g., control assignment 1029) may, contrary to any opposing command (e.g., received in the interceptor), control the propeller(s) to a speed corresponding to increased (e.g., dangerous) vibrations. Rotating The system is designed so that it does not command (for example, cannot command). In some embodiments, the RPM prohibition 1033a may provide the flight control law (e.g., control assignment 1029) with available propeller speeds excluding the propeller speed prohibition range, and / or may provide the propeller speed prohibition range (corresponding to increased vibration). The flight control law determines the torque associated with the received propeller speed value and controls the propeller speed to avoid increased (e.g., dangerous) vibration in violation of any contradictory command (e.g., received at the interceptor).

[0105] As shown in Figure 16B, in some embodiments, the RPM prohibition 1033a may apply soft constraints for one or more propeller speed prohibition ranges. In some embodiments, the system 1000 may include control assignment functions (e.g., online control assignments and / or optimization functions(s)) for determining propeller commands given a variety of inputs such as commanded aircraft condition requirements (e.g., aircraft thrust and / or moments), hard constraints, and soft constraints. For example, control assignment 1029 may determine propeller commands considering load and maneuverability reduction preferences, battery pack conditions, and / or flight condition constraints (e.g., maximum propeller RPM to avoid vortex ring conditions).

[0106] In some embodiments, the aircraft may operate redundantly, and the control assignment 1029 may be configured to generate multiple solutions for each set of commands (e.g., commands from the inner-loop control law 1028). Based on the multiple solutions, the control assignment 1029 may determine an optimal solution based on constraints. In some embodiments, one or more soft constraints may be applied as attractors. The control assignment 1029 may apply propeller parameters indicating each target torque value and / or corresponding target propeller speed as attractors in the assignment function (e.g., an assignment function configured to determine a combination of propeller commands to achieve a determined thrust). The RPM prohibition 1033a may move and / or apply at least one attractor (e.g., an attractor value, a set of attractor values, an attractor curve, an attractor manifold, or other attractor state representation) configured to cause the system 1000 to avoid using torque values ​​corresponding to propeller speeds within the propeller speed prohibition band. For example, to avoid the propeller torque command corresponding to the propeller speed prohibition zone 1601, the RPM prohibition 1033a may set the attractor 1603 or move the existing attractor 1604 to the position indicated for attractor 1603. Thus, the control assignment 1029 is the propeller speed corresponding to this propeller's more severe vibrations. Rotating The system prioritizes control solutions for electric engines(s) that avoid being commanded. As described above, in some embodiments, the propeller speed no-go zone may vary for each propeller (e.g., based on the propeller angle). In some embodiments, the attractor may be determined for each propeller and / or group of propellers of the aircraft (e.g., all propellers with similar propeller angles).

[0107] In some embodiments, a combination of soft and hard constraints may be employed. The vibration damping 1033 may apply soft constraints (e.g., attractor values ​​shown in Figure 16B) for forbidden bands associated with less severe vibrations. For example, the vibration damping 1033 may apply soft constraints when the expected vibration is below a stored threshold. The vibration damping 1033 may apply hard constraints (e.g., division ranges shown in Figure 16A) for forbidden bands associated with more severe vibrations. For example, the vibration damping 1033 may apply hard constraints when the expected vibration is above a stored threshold.

[0108] While the propeller speed control described above is based on avoiding increased vibration, in some embodiments, the RPM no-go zone may correspond to propeller speeds that generate excessive noise emission. For example, RPM no-go 1033a may store propeller speed no-go zones that satisfy noise objectives based on modeling and / or testing the effect of propeller speed on aircraft noise emission (e.g., psychoacoustic noise). In some embodiments, RPM no-go 1033a and / or system 1000 may prioritize between vibration objectives and noise objectives. For example, in some embodiments, if it is not possible to determine that a combination of propeller speeds satisfies both objectives while providing the required thrust, the vibration objective (e.g., avoiding the RPM no-go zone) may take precedence. In some embodiments, RPM no-go 1033a and / or system 1000 may prioritize between vibration objectives, noise objectives, and / or other criteria (e.g., other soft constraints described above). In some embodiments, the prioritization may vary based on the flight phase. For example, the noise objective may be prioritized during the hovering phase (e.g., when the aircraft is landing or taking off). And when approaching people on earth ) gives more weight Retoku In the forward flight phase, noise-related objectives may be given lower priority or even eliminated.

[0109] Figure 16C illustrates a process for avoiding increased propeller speed with vibration, consistent with the disclosed embodiments. In some embodiments, the vibration damper 1033 may determine hard and / or soft constraints, as described above with respect to Figures 16A and 16B. These constraints may be provided to a control assignment 1029, which may generate one or more electric engine commands (e.g., torque commands) based on the constraints.

[0110] Figure 16D illustrates another process for avoiding propeller speeds accompanied by increased vibration, consistent with the disclosed embodiments. In some embodiments, the vibration damper 1033 may compare the measured propeller speed (e.g., from vehicle detection 1031) to a propeller speed no-go range(s) and adjust the electric engine command (e.g., torque command), thereby causing an increase or decrease of one or more propeller speeds if the measured propeller speed is within the propeller speed no-go range. In some embodiments, adjusting the electric engine command (e.g., torque command) may involve determining the difference between the measured propeller speed and the edge of the propeller speed no-go range. In some embodiments, the vibration damper 1033 may then adjust the electric engine command based on this difference. For example, the vibration damper 1033 may make a proportional adjustment to the electric engine command based on the percentage of deviation from the edge of the propeller speed no-go range and / or an adjustment based on a torque difference (measured-no-go edge) determined using the torque-speed relationship of the flight phase. In some embodiments, as described above, the vibration damper 1033 may apply or move the torque attractor to cause the propeller speed to deviate from the propeller speed restriction zone. The control assignment 1029 may transmit electric engine commands to control the electric engine.

[0111] Figure 16E illustrates another process for avoiding increased propeller speed with vibration, consistent with the disclosed embodiments. In some embodiments, as described above with respect to Figure 16C, the electric engine command is based on a propeller speed no-go zone (for example, using hard and / or soft constraints shown in Figures 16A–16B).

[0112] In some embodiments, as described above with reference to Figure 16D, the vibration damper 1033 compares the measured propeller speed to a propeller speed prohibition range(s) and may adjust the electric engine command if the measured propeller speed is within the propeller speed prohibition range. The control assignment 1029 may transmit an electric engine command to control the electric engine.

[0113] Figure 17A illustrates a block diagram for vibration damping based on dividing the propeller speed among multiple propellers using a feedforward configuration, consistent with the disclosed embodiment. In step 1720, the RPM division 1033b may receive a commanded aircraft state (e.g., it may receive a pilot input indicating a commanded aircraft state). For example, the RPM division 1033b may receive a commanded aircraft state from one or more pilot inceptors, an autopilot system, and / or other functions of system 1000 (e.g., from the inner-loop control law 1028). In some embodiments, the commanded aircraft state may be a steady state (e.g., maintaining the direction of flight).

[0114] Step 1720 may also include determining aircraft thrust to achieve a commanded aircraft state (e.g., according to control assignment 1029) and / or to maintain an existing aircraft state (e.g., aircraft trim, aircraft speed, flight state, altitude, and / or a combination thereof) (e.g., within one or more threshold margins). In some embodiments, aircraft thrust may be associated with force vectors applied by the aircraft propellers (e.g., may include force vectors, may be represented by force vectors, and may be achieved by force vectors). In step 1722, RPM division 1033b and / or another function of system 1000 may take at least one propeller parameter associated with a propeller speed to avoid an increased (e.g., dangerous) vibration response in the aircraft. Additionally, RPM division 1033b and / or another function of system 1000 may determine, based on at least one propeller parameter, a respective command for each propeller of the aircraft to achieve the determined aircraft thrust. For example, RPM division 1033b and / or another function of system 1000 can apply the same propeller speed to multiple propellers (e.g., all propellers on an aircraft, a given set of propellers on an aircraft). Rotating While avoiding direct commanding, it is possible to determine the propeller speed(s) and / or torque that match the thrust requirements of the commanded aircraft state.

[0115] In some embodiments, the vibration damper 1033 may determine the respective commands for each propeller of the aircraft based on determining a combination of propeller commands (e.g., commands to each propeller of the aircraft) that result in each propeller of the aircraft being controlled to a different speed (e.g., according to the minimum difference between propellers and / or the total difference). In some embodiments, the vibration damper 1033 may determine the respective commands for each propeller of the aircraft based on determining a combination of propeller commands that result in each propeller on a wing (e.g., the left wing or the right wing) being controlled to a different speed.

[0116] In some embodiments, the RPM division 1033b may determine and / or store a propeller speed difference to apply to ensure that each propeller speed for each propeller is different from all other propeller speeds on the aircraft. For example, in some embodiments, the RPM division 1033b may determine and / or store a total speed difference to which the propeller speeds are distributed (e.g., a total of 500 RPM across all propellers between the fastest and slowest propellers on the aircraft). In some embodiments, the RPM division 1033b may determine and / or store a speed difference(s) between individual propellers (e.g., the speed difference between each propeller for all propellers on the aircraft). In some embodiments, although the term “difference” is used, it is understood that a range(s) may be used instead of, or in addition to, one or more differences.

[0117] In some embodiments, the RPM division 1033b may store the velocity difference(s) for each propeller, and these differences may ensure that the aircraft's orientation (e.g., yaw, roll, and / or bank), lift, and / or forward thrust remain unchanged (or change only minimally under higher priority constraints). For example, a reduced propeller velocity for one propeller on the side of the wing may be offset by an increased propeller velocity for another propeller on the same side of the wing.

[0118] In some embodiments, the RPM division 1033b may store one or more functions that randomly apply a propeller speed difference to each propeller. For example, each propeller speed may be varied by a random amount such that the total propeller speed change is distributed across a set total speed difference. In some embodiments, the initial propeller speed (and / or torque command) for each propeller is determined (e.g., by system 1000) to achieve a commanded aircraft state, and then the initial propeller speed (and / or torque command) is applied to multiple propellers with the same propeller speed (e.g., by adjusting the propeller speeds by a random amount to satisfy the total speed difference, as described above). RotatingIt is adjusted to avoid issuing such a command.

[0119] In some embodiments, the stored and / or determined propeller speed differences may be selected to satisfy vibration criteria, noise criteria, fatigue life targets (e.g., aircraft structures, frames, and / or equipment), cabin vibration criteria, and / or other defined objectives. For example, RPM division 1033b may store propeller speed differences that satisfy these objectives based on modeling and / or testing (e.g., physical tests, virtual tests, or machine learning-based tests) the effect of propeller speed on aircraft vibration and / or noise. In some embodiments, the propeller speed differences may correspond to differences in propeller speed between individual propellers ranging from 0.5% to 10%.

[0120] In some embodiments, the RPM division 1033b may determine the propeller speed difference based on one or more flight conditions. For example, the RPM division 1033b may determine the propeller speed difference based on one or more of the following: propeller speed(s) (e.g., average propeller speed across a group or all propellers), propeller tilt angle(s) (e.g., average tilt angle), or airspeed. For example, the RPM division 1033b may determine a larger speed difference under certain flight conditions where vibrations are more severe, such as when the propeller rotation axis is perpendicular to the aircraft trajectory (e.g., in a lift configuration) and the airspeed is higher (greater, indicating airflow along the edges). Thus, the RPM division 1033b may determine the propeller speed difference (e.g., between individual propellers and / or between all propellers) based on airspeed and propeller angle, which indicate increased airflow along the edges. Speed ​​difference ) may be increased. The velocity difference(s) applied based on the flight conditions may be stored in one or more models, tables, and / or algorithms in system 1000 (e.g., RPM partition 1033b) and referenced by RPM partition 1033b to dynamically change the velocity difference(s) throughout the flight.

[0121] In some embodiments, one or more functions of system 1000 may determine whether the thrust provided by the propeller is sufficient at the changed propeller speed and / or whether other aircraft constraints are met. For example, as described above, control assignment 1029 may store one or more optimizer functions that determine engine commands (e.g., torque commands) that achieve a commanded aircraft state while satisfying other hard and / or soft constraints. In some embodiments, RPM division 1033b may determine the changes in torque and / or thrust corresponding to the change in propeller speed. For example, RPM division 1033b may determine the propeller torque and / or thrust corresponding to the propeller at the changed speed by referring to one or more relationships (e.g., Figure 15).

[0122] In some embodiments, control assignment 1029 may determine whether the torque and / or thrust of the propeller at the changed speed meets other constraints, such as maintaining support for lift and / or forward thrust, meeting load requirements (e.g., root load on the wing), meeting battery requirements, meeting high-voltage power limit requirements, avoiding the RPM no-go zone, and meeting engine thermal requirements. In some embodiments, if the propeller at the changed speed does not meet these requirements, RPM division 1033b and / or control assignment 1029 may adjust the propeller speed(s) of one or more propellers to meet the constraints. In some embodiments, RPM division 1033b may apply the torque at the changed propeller speed(s) as a soft constraint (e.g., to control assignment 1029). For example, RPM division 1033b may apply attractor values ​​for each propeller corresponding to the torque at the changed propeller speed(s).

[0123] In some embodiments, the RPM division 1033b may randomly assign different torque values ​​to different propellers (e.g., from the commanded AC state in step 1720) in order to satisfy the target aircraft thrust. The propellers will move at different speeds while maintaining the aircraft's trim state (e.g., trim of effectors such as the propeller and aircraft control surfaces, which may be determined by pilot input and / or control laws). Rotating These can be commanded. In some embodiments, in response to a change in aircraft trim, the speed of one or more propellers can be changed to maintain the updated aircraft trim while still targeting a reduction in vibration response. In some embodiments, the aircraft trim state can be maintained within a threshold margin. In some embodiments, the random assignment of torque values ​​can span a set total torque value difference. As described above, in some embodiments, propeller speed and / or torque can be determined based on one or more trim state constraints (e.g., constraints configured to maintain a trim state). For example, a combination of signal outputs that control aircraft components to satisfy one or more trim states can be determined (e.g., by the FCC), and the propeller speed and / or torque values ​​can be determined to fall within or be compatible with at least one of these combinations.

[0124] In some embodiments, following a random assignment of torque values, the RPM division 1033b may check whether there is sufficient variance in the propeller velocities corresponding to the torque values. The RPM division 1033b may check whether there is sufficient variance in the propeller velocities based on stored parameters (e.g., threshold(s), range(s)) that indicate the required variance. For example, the propeller velocities corresponding to the propeller torque may be determined (e.g., using the relationship(s) in Figure 15), and the standard deviation between the propeller velocities may be calculated. If the standard deviation does not meet or exceed the stored threshold, the system 1000 may reassign different random torque values ​​to the propellers. Furthermore, as described above, in some embodiments, this standard deviation may vary based on the aircraft's flight conditions. For example, RPM division 1033b may determine larger velocity differences under certain flight conditions where vibrations are more severe, such as when the propeller rotation axis is perpendicular to the aircraft trajectory (e.g., in a lift configuration) and when the airspeed is higher (indicating greater airflow along the edges). This process may be repeated until a torque assignment that satisfies the desired distribution of propeller velocity is achieved.

[0125] In any of the embodiments described above, the stored and / or determined propeller speed difference, and / or variance parameters (e.g., standard deviation) may be selected to satisfy vibration targets, noise targets, fatigue life targets (e.g., aircraft structures, frames, and / or equipment), cabin vibration criteria, and / or other defined objectives (e.g., represented by constraints, weights, or attractors). For example, RPM division 1033b may store propeller speed difference and / or variance parameters that satisfy vibration objectives based on modeling and / or testing the effect of propeller speed on the physical vibrations of the aircraft and / or the vibrations of structural components of the aircraft (e.g., aircraft body, propellers, booms, wings, etc.). For example, RPM division 1033b may store propeller speed difference and / or variance parameters that satisfy noise objectives based on modeling and / or testing the effect of propeller speed on the noise emissions of the aircraft (e.g., psychoacoustic noise). Testing may involve physical testing, virtual testing, or machine learning-based testing. In some embodiments, the propeller speed difference may correspond to a difference in propeller speed between individual propellers ranging from 0.5% to 10%.

[0126] In some embodiments, the RPM division 1033b and / or system 1000 may combine both vibration and noise objectives. For example, the propeller speed difference and / or dispersion parameter may include a speed difference and / or dispersion parameter that satisfies the more stringent of the two objectives (e.g., one requiring a larger difference in propeller speed). In some embodiments, the RPM division 1033b and / or system 1000 may be prioritized among vibration objectives, noise objectives, and / or other criteria (e.g., other soft constraints mentioned above). In some embodiments, the prioritization may vary based on the flight phase. For example, the noise objective may be given more weight during the hovering phase when the aircraft is landing and / or taking off and approaching people on the ground. In the forward flight phase, the noise objective may be given lower priority and / or removed.

[0127] In some embodiments, before applying the propeller speed changes described above, another function of RPM division 1033b and / or system 1000 may determine whether the aircraft is in a steady state. For example, RPM division 1033b and / or another function of system 1000 may determine whether aircraft control is commanded, for example, by detecting a pilot input request for control (e.g., on an interceptor) and / or by detecting a requested change in aircraft state (e.g., a modeled change in aircraft state and / or a change in at least one of commanded roll, yaw, or pitch). In some embodiments, RPM division 1033b may apply the propeller speed difference only when aircraft control is not commanded.

[0128] In step 1724, system 1000 may control the flight elements to achieve a commanded aircraft state while varying the propeller speed. For example, system 1000 may control each propeller of the aircraft based on (e.g., using and depending on) their respective corresponding commands. For example, system 1000 may command the aircraft propellers (e.g., via torque commands) to achieve lift and / or forward thrust while simultaneously maintaining a propeller speed difference. In some embodiments, RPM division 1033b and / or another function of system 1000 may refer to the torque-speed relationship to determine the torque command corresponding to the propeller speed (e.g., Figure 15).

[0129] In step 1726, the propeller can operate at a commanded speed. In step 1728, vibrations in the aircraft structure are mitigated based on the propeller operating at different speeds, and thus the magnitude of vibrations and / or fatigue loads caused by vibrations can be reduced. Furthermore, in some embodiments, noise emissions (e.g., psychoacoustic noise) can be reduced as described above with reference to step 1722.

[0130] Figure 17B illustrates another block diagram for vibration damping based on dividing propeller speed among multiple propellers using a feedback configuration, consistent with the disclosed embodiment. In step 1736, system 1000 and / or RPM division 1033b may detect structural vibration response in the aircraft (e.g., vibration of the aircraft or aircraft components) from vehicle detection 1031. For example, system 1000 may detect aircraft vibration based on measurements from an inertial navigation system, inertial measurement unit(s), and / or inertial sensors (e.g., accelerometers, gyroscopes, magnetometers). In some embodiments, system 1000 may receive vibration measurements from multi-axis accelerometer(s) (e.g., 3-axis accelerometer) and / or single-axis accelerometer(s). In some embodiments, system 1000 and / or RPM division 1033b may additionally and / or alternatively detect noise emission based on measurements from one or more microphones inside and / or on the aircraft.

[0131] In step 1738, system 1000 and / or RPM division 1033b may determine whether vibrations and / or noises (such as those measured by at least one accelerometer and / or at least one microphone) meet threshold requirements for dividing the propeller speed. For example, total vibrations (e.g., frequency or amplitude) may be compared to a single threshold. Additionally or alternatively, vibrations along a first axis, a second axis, and / or a third axis (e.g., longitudinal, vertical, and / or transverse) may be compared to the first threshold, the second threshold, and / or the third threshold. For example, lower thresholds may be set for particularly undesirable vibrations (e.g., vertical cabin vibrations). Furthermore, vibration measurements for comparison with the threshold(s) may be based on measurements from a combination of inertial sensors. In some embodiments, multiple accelerometers may be positioned throughout the aircraft, and the total vibration value may be determined based on the average (e.g., weighted average) of the values ​​from these accelerometers. For example, accelerometers may be placed in close proximity to different structural components (e.g., on the fuselage, on the EPU, on the propeller, on the propeller shaft), and acceleration values ​​with higher sensitivity (e.g., values ​​corresponding to the natural frequencies of this component) may be weighted more heavily. System 1000 and / or RPM division 1033b may determine whether vibrations in the aircraft exceed a threshold level(s) and / or exceed a threshold level(s) for a set period of time. In some embodiments, an integrator threshold may be used to determine when to implement a vibration damping function (e.g., when the integrator integrates the vibration of a threshold quantity over time).

[0132] In some embodiments, the threshold may include a range of values, and system 1000 and / or RPM division 1033b may determine that at least one threshold is met if vibration values ​​(e.g., amplitude and / or frequency measured by an accelerometer) reflecting the structural vibration response of the aircraft are within this range and / or remain within this range for a certain period of time. For example, in some embodiments, ride comfort may take precedence, and the threshold requirement may be considered met if the frequency value (e.g., derived from one or more acceleration values) is within the range of 1 Hz to 80 Hz. In some embodiments, system vibrations (e.g., vibrations of the aircraft, structure, frame, and / or equipment) may take precedence, and the threshold requirement may be considered met if the frequency value is within 5 Hz to 2,000 Hz or 10 Hz to 500 Hz. In some embodiments, reducing ride comfort vibrations and / or system vibrations may take precedence over reducing noise emissions.

[0133] In some embodiments, system 1000 and / or RPM division 1033b may additionally detect whether one or more noise emissions meet threshold requirements. For example, a total noise value (e.g., decibel value, Hz value, amplitude value, or any combination thereof) that can be measured from a microphone(s) may be compared to a threshold(s). Furthermore, the noise value for comparison with the threshold(s) may be based on measurements from multiple microphones. In some embodiments, multiple microphones may be placed throughout the aircraft, and the total noise value may be determined based on the average (e.g., weighted average) of the values ​​from these microphones. System 1000 and / or RPM division 1033b may determine whether the noise value in the aircraft meets a threshold(s) and / or whether it meets a threshold(s) for a set period of time. In some embodiments, an integrator threshold may be used to determine when an oscillation damping function should be implemented (e.g., when an integrator integrates the noise of a threshold quantity over time). In some embodiments, the noise emission threshold requirement may be considered met if the noise level (measured, e.g., by one or more microphones) is within the range of 20 Hz to 10,000 Hz or 20 Hz to 1,000 Hz. Optionally, the noise emission threshold requirement may be considered met if the noise level (measured, e.g., by one or more microphones) is within the range of 20 Hz to 10,000 Hz or 20 Hz to 1,000 Hz and is below a threshold decibel value (e.g., less than 120 dB). In some embodiments, the noise emission threshold requirement may be determined based on measurements from one or more accelerometers. For example, accelerometer measurement threshold requirements corresponding to higher noise emission may be based on modeling or experimental data establishing a relationship between accelerometer readings and noise emission (e.g., detected through microphones).

[0134] In some embodiments, reducing noise emissions may be a lower priority compared to reducing structural vibration response, including, for example, ride vibration and / or system vibration. In some embodiments, system 1000 and / or RPM division 1033b may prioritize reducing system vibration by applying a vibration damping function, which may thereby produce a suboptimal result for noise generated by the aircraft. For example, applying a vibration damping function may reduce vibrations from 5 Hz to 2,000 Hz but increase vibrations at higher frequencies, such as 8,000 Hz (i.e., noise generation). The range provided in this disclosure encompasses boundary values. For example, within 5 Hz to 2,000 Hz, 5 Hz and 2,000 Hz are included.

[0135] In step 1740, based on the determination that the threshold requirement is met, RPM division 1033b and / or another function of system 1000 apply the same propeller speed to multiple propellers (e.g., all propellers of an aircraft, a given set of propellers of an aircraft). Rotating It is possible to determine propeller speed(s) and / or torque that satisfy the aircraft's thrust requirements while avoiding commanding such speeds. For example, RPM division 1033b and / or another function of system 1000 may determine propeller speed(s) and / or torque using one of the methods described above with reference to step 1722 of Figure 17A. As described above with reference to step 1722 of Figure 17A, in some embodiments, when the aircraft's maneuver is commanded, the propeller speed is not adjusted to avoid matching propeller speeds.

[0136] As described above, in some embodiments, reducing the structural vibration response in an aircraft may be a lower priority than reducing noise emissions. For example, in step 1738, it may be determined that the noise meets the threshold requirements for splitting the propeller speed. The split propeller speed (e.g., propeller parameter(s)) may be determined to meet the commanded lift and / or thrust. System 1000 and / or RPM split 1033b may evaluate the split propeller speed to determine the expected impact on structural vibration. For example, System 1000 and / or RPM split 1033b may determine whether controlling the propeller at the split RPM speed (e.g., based on the fact that it is within a propeller speed range associated with undesirable frequencies and / or another propeller speed prohibition region) could increase structural vibration. In some embodiments, the propeller is split based on the determination that structural vibration will not increase. RPM The speed can be controlled. In some embodiments, the propeller is not controlled to a segmented propeller speed based on the determination that this would result in increased structural vibration. If the propeller is not controlled to a segmented propeller speed, the system 1000 and / or RPM segment 1033b may continue to monitor vibration and / or noise in step 1734.

[0137] In step 1730, the system 1000 may control the flight elements to achieve a commanded aircraft state based on the changed propeller speed. For example, the system 1000 may command the aircraft propellers so that a commanded lift and / or forward thrust is achieved while simultaneously maintaining a difference in propeller speed. In some embodiments, the RPM division 1033b and / or another function of the system 1000 may refer to the torque-speed relationship to determine the torque command corresponding to the propeller speed (e.g., Figure 15). In step 1732, the propellers may operate at the commanded speed. In step 1734, aircraft structural vibrations are improved based on the propellers operating at different speeds, and therefore the vibrations and / or the magnitude of fatigue loads caused by the vibrations may be reduced. Furthermore, in some embodiments, noise emissions from the aircraft may be reduced. The vibration response may be detected again in step 1736, and the process may be repeated.

[0138] Figure 17C illustrates a block diagram showing how the propeller speed difference is commanded, consistent with the disclosed embodiment. In step 1740, the system 1000 commands a target thrust (e.g., F z ) can be specified. For example, outer loop assignment 1026 and / or inner loop Control Law1028 may determine the target thrust of the aircraft based on pilot input (e.g., pilot input indicating a commanded aircraft state) and one or more control laws. Furthermore, control assignment 1029 may determine the amount of thrust for each propeller based on the aircraft thrust requirements. In step 1742, RPM division 1033b and / or another function of system 1000 may convert the target thrust into electric engine commands and / or propeller speeds based on the flight phase. For example, RPM division 1033b and / or another function of system 1000 may use one or more aerodynamic models, functions, or lookup tables to determine the electric engine commands and / or propeller speeds to satisfy the target thrust. In step 1744, as described above, the determined propeller speeds may be applied to multiple propellers (e.g., all propellers of the aircraft, a given set of propellers of the aircraft) to improve the aircraft's vibration response. Rotating It may be configured to avoid issuing commands. For example, the optimizer function (e.g., control assignment 1029) may receive the total propeller speed difference and / or propeller speed difference between different propellers to optimize vibration. The optimizer function may determine electric engine commands(s) for the propellers to operate at different speeds while satisfying other aircraft constraints. In some embodiments, the different propeller speeds may be determined to satisfy standards (e.g., vibration standards (e.g., ISO-2631), noise standards, fatigue life targets for aircraft structures, frames, and / or equipment, cabin vibration standards, or any other standardization purposes).

[0139] Figure 17D illustrates a torque command for offsetting the propeller speed, consistent with the disclosed embodiment. System 1000 controls the propeller speed based on pilot input and / or autopilot input, as well as flight control Rule 1Based on 453, at least one thrust command 1760a for a propeller can be determined. For example, system 1000 can determine thrust commands for all propellers to achieve a commanded aircraft state (e.g., thrust vector command and / or moment command). System 1000 can determine torque commands and / or propeller speeds 1760b corresponding to the thrust command 1760a. For example, system 1000 can determine the corresponding torque commands and / or propeller speeds to satisfy the thrust command using one or more aerodynamic models (e.g., Figure 15), functions, or lookup tables.

[0140] As described above, RPM division 1033b and / or another function of system 1000 may adjust the torque command to generate a speed difference between the propellers while satisfying the commanded aircraft thrust vector and / or moment command. For example, the determined propeller speed for propeller 1 is reduced by dRPM1 and dF z1 This can result in a thrust reduction of only dF. The determined propeller speed for propeller 2 increases by only dRPM2, and dF z2 This can result in a thrust increase of that magnitude. Thus, the aircraft's commanded state (e.g., thrust vector and / or moment command) is met while mitigating the effects of propeller vibration.

[0141] The above description is provided for illustrative purposes only. It is not exhaustive and does not limit the invention to the exact form or embodiment disclosed herein. Modifications and adaptations of the invention will be apparent to those skilled in the art from the examination herein and the practice of the disclosed embodiments of the invention disclosed herein.

[0142] The features and advantages of this disclosure are evident from the detailed specification, and therefore the attached claims are intended to cover all systems and methods included in the true spirit and scope of this disclosure. As used herein, the indefinite articles "a" and "an" mean "one or more." Similarly, the use of plural terms does not necessarily mean plural unless it is not ambiguous in the given context. Words such as "and" or "or" mean "and / or" unless otherwise indicated. Furthermore, since numerous modifications and variations can easily arise from examining this disclosure, it is not desirable to limit this disclosure to the exact configurations and operations illustrated and described, and therefore all suitable modifications and equivalents included in the scope of this disclosure may be applicable.

[0143] Other embodiments will be apparent to those skilled in the art from the examination of this specification and the practice of the implementations disclosed herein. The architectures and circuit layouts shown in the figures are intended for illustrative purposes only and are not intended to be limited to the specific configurations and circuit layouts shown in the figures. Furthermore, this specification and the examples are intended to be considered merely illustrative, and the true scope and spirit of the invention are set forth by the following claims. The above description is presented for illustrative purposes only. It is not exhaustive and does not limit the invention to the exact forms or embodiments disclosed herein. Modifications and adaptations of the invention will be apparent to those skilled in the art from the examination of this specification and the practice of the disclosed embodiments of the invention disclosed herein.

[0144] Clause This embodiment may be further described using the following clauses. 1. A method for controlling an aircraft, Receiving pilot input indicating the commanded aircraft status, To determine the aircraft thrust required to achieve the commanded aircraft state, Extracting at least one propeller parameter associated with propeller speed, wherein the propeller parameter is determined to reduce the structural vibration response in the aircraft, Based on the at least one propeller parameter, determine the respective commands for each propeller of the aircraft to achieve the determined aircraft thrust, A method comprising controlling each propeller of the aircraft based on corresponding commands. 2. Determining whether the commanded aircraft state corresponds to a steady state, The method according to Clause 1, further comprising determining that the commanded aircraft state corresponds to a steady state, taking the at least one propeller parameter, wherein the steady state is further configured to include at least one of the following: the roll of the aircraft remains constant, the yaw of the aircraft remains constant, or the pitch of the aircraft remains constant. 3. Receiving sensor data indicating aircraft vibration, Based on the received sensor data, it is determined whether the aircraft vibration exceeds a threshold, The method according to clause 1 or 2, further comprising: determining that the aircraft vibration exceeds the threshold; taking out the at least one propeller parameter. 4. The method according to any one of the clauses 1 to 3, wherein the at least one propeller parameter indicates a difference in propeller speed applied between the propellers of the aircraft. 5. The method according to any one of the clauses 1 to 4, wherein the at least one propeller parameter represents at least one of the following: the difference in the sum of propeller speeds across all propellers of the aircraft, or the difference in propeller speeds between pairs of propellers of the aircraft. 6. The method according to any one of the clauses 1 to 5, wherein the respective commands for each propeller of the aircraft are determined on the basis of determining a combination of propeller commands that result in each propeller of the aircraft being controlled to a different speed. 7. Determining the respective commands for each propeller of the aircraft to satisfy the determined aircraft thrust based on the at least one propeller parameter is: For each propeller of the aforementioned aircraft, the first propeller command to satisfy the determined thrust is to be determined, Randomly adjusting the initial propeller command based on at least one of the propeller parameters, The method of Clause 6, further comprising determining whether the randomly adjusted propeller command provides the determined thrust. 8. The at least one propeller parameter indicates the difference in propeller speed applied between the propellers of the aircraft, The method according to any one of the claims 1 to 7, further comprising determining the difference in propeller speeds based on at least one of airspeed or propeller angle. 9. The method of the present invention, further comprising increasing the difference in propeller speeds based on the airspeed and propeller angle indicating airflow along the larger edge. 10. The method according to any one of the clauses 1 to 9, wherein the at least one propeller parameter indicates a propeller speed range to be avoided. 11. The at least one propeller parameter includes at least two propeller speed avoidance ranges, The aforementioned method, The aforementioned airspeed and The aforementioned The method according to any one of the clauses 1 to 10, further comprising extracting a larger propeller speed avoidance range based on the propeller angle indicating airflow along the larger edge. 12. The method according to any one of the clauses 1 to 11, wherein the at least one propeller parameter indicates at least one of a propeller speed range to be avoided, a propeller speed range to be maintained, or a target propeller speed outside the propeller speed range to be avoided. 13. The at least one propeller parameter indicates the respective target propeller speed for each propeller of the aircraft. Determining the respective commands for each propeller of the aircraft to satisfy the determined thrust based on the at least one propeller parameter is: The method according to any one of the clauses 1 to 12, comprising applying the propeller parameters indicating each target propeller speed as attractors in an assignment function, wherein the assignment function determines a combination of propeller commands to achieve the determined thrust. 14. The method according to any one of the claims 1 to 13, further comprising changing the at least one propeller parameter based on the airspeed of the aircraft or the propeller angle. 15. Receiving first sensor data indicating the airspeed of the aircraft, Receiving second sensor data indicating the propeller angle, The method according to any one of the claims 1 to 14, further comprising changing the at least one propeller parameter based on the first sensor data and the second sensor data. 16. The at least one propeller parameter is torque, The method according to any one of the claims 1 to 15, further comprising determining the at least one propeller parameter based on the relationship between propeller speed and torque, wherein the relationship between propeller speed and torque changes based on the flight phase of the aircraft. 17. Receiving sensor data indicating the propeller speed of each propeller of the aircraft, The method according to any one of the claims 1 to 16, further comprising determining the command for each propeller of the aircraft based on the at least one propeller parameter and the sensor data for the corresponding propeller. 18. Receiving sensor data indicating the propeller speed of each propeller, Controlling each propeller of the aircraft, according to any one of the claims 1 to 17, further comprising adjusting the determined command based on the received sensor data for the corresponding propeller, based on the adjusted command. 19. The at least one propeller parameter includes at least two parameters, The first parameter indicates the propeller speed avoidance range. The second parameter indicates the difference in propeller speed applied between the propellers of the aircraft. The method described in any one of the clauses 1 to 18, wherein determining the respective instructions for each propeller of the aircraft includes giving priority to the first parameter over the second parameter. 20. The at least one propeller parameter changes based on the flight conditions of the aircraft. The aforementioned method, The method according to any one of the claims 1 to 19, further comprising repeatedly taking the at least one propeller parameter throughout the entire flight of the aircraft and controlling the aircraft based on the at least one propeller parameter. 21. The method according to any one of the clauses 1 to 20, wherein the propeller parameters are determined by experimentally testing or modeling the effect of propeller speed on the structural vibration response of at least one of the aircraft body, the aircraft boom, the aircraft propeller, or the aircraft wing. 22. The propeller parameter as described in any one of the clauses 1 to 21, wherein the propeller parameter indicates the standard deviation required between the propeller speeds. 23. Randomly assign torque values ​​to each of the propellers so as to satisfy the determined thrust. The random assignment of propeller torque determines whether the required standard deviation of the propeller speed is met. If it is determined that the aforementioned standard deviation of the propeller speed is not met, the aforementioned random assignment of torque values ​​is repeated. The method according to Clause 22, further comprising determining the respective commands for each propeller of the aircraft when it is determined that the standard deviation of the propeller speed is satisfied. 24. The method described in any one of the provisions 1 to 23, wherein each of the instructions is determined to maintain the trim state of the aircraft. 25. Extracting a second propeller parameter, wherein the second propeller parameter is determined to reduce noise emissions from the aircraft. To determine whether the aircraft can be controlled according to the second propeller parameter without increasing the structural vibration response of the aircraft, The method according to any one of the claims 1 to 24, further comprising: determining that the structural vibration response in the aircraft does not increase; and controlling each propeller of the aircraft based on the second propeller parameter. 26. An electrical system comprising at least one processor configured to execute instructions, wherein the instructions cause the system to perform any one of the clauses 1 to 25. 27. A computer-readable storage medium storing instructions, wherein, when executed by at least one processor, the instructions cause the at least one processor to perform the method described in any one of the clauses 1 to 25. 28. An aircraft having at least one processor configured to implement any one of the provisions 1 to 25.

Claims

1. An electrical system for aircraft, The system comprises at least one processor, and the at least one processor executes instructions to the system. It receives pilot input indicating the commanded aircraft status, Determine the aircraft thrust required to achieve the commanded aircraft state. At least one propeller parameter associated with propeller speed is extracted, and the propeller parameter is determined to reduce the structural vibration response in the aircraft. Based on the at least one propeller parameter, a command for each propeller of the aircraft is determined to achieve the determined aircraft thrust. Based on the corresponding commands, each propeller of the aircraft is controlled. An electrical system configured in such a way.

2. The aforementioned at least one processor is Determine whether the commanded aircraft state corresponds to a steady state. When it is determined that the commanded aircraft state corresponds to a steady state, the at least one propeller parameter is taken, and the steady state includes at least one of the following: the aircraft's roll remains constant, the aircraft's yaw remains constant, or the aircraft's pitch remains constant. The electrical system according to claim 1, further configured as follows.

3. The aforementioned at least one processor is Received sensor data indicating aircraft vibration, Based on the received sensor data, it is determined whether the aircraft vibration exceeds a threshold. If it is determined that the aircraft vibration exceeds the threshold, the at least one propeller parameter is extracted. The electrical system according to claim 1 or 2, further configured as follows.

4. The electrical system according to any one of claims 1 to 3, wherein the at least one propeller parameter indicates a difference in propeller speed applied between the propellers of the aircraft.

5. The electrical system according to any one of claims 1 to 4, wherein the at least one propeller parameter represents at least one of the following: the difference in the sum of propeller speeds across all the propellers of the aircraft, or the difference in propeller speeds between pairs of propellers of the aircraft.

6. The electrical system according to any one of claims 1 to 5, wherein the respective command for each propeller of the aircraft is determined based on determining a combination of propeller commands that results in each propeller of the aircraft being controlled to a different speed.

7. Determining the respective commands for each propeller of the aircraft to satisfy the determined aircraft thrust based on the at least one propeller parameter is: For each propeller of the aforementioned aircraft, the first propeller command to satisfy the determined thrust is to be determined, The initial propeller command is randomly adjusted based on at least one of the propeller parameters. Determining whether the randomly adjusted propeller command provides the determined thrust, The electrical system according to claim 6, further comprising:

8. The aforementioned at least one propeller parameter indicates the difference in propeller speed applied between the propellers of the aircraft, The electrical system according to any one of claims 1 to 7, wherein the at least one processor is further configured to determine the difference in propeller speeds based on at least one of airspeed or propeller angle.

9. The aforementioned at least one processor is The electrical system according to claim 8, further configured to increase the difference in propeller speeds based on the fact that the airspeed and propeller angle indicate an increase in airflow along the edge.

10. The electrical system according to any one of claims 1 to 9, wherein the at least one propeller parameter indicates a propeller speed range to be avoided.

11. The aforementioned at least one propeller parameter includes at least two propeller speed avoidance ranges, The aforementioned at least one processor is The electrical system according to any one of claims 1 to 10, further configured to increase the propeller speed avoidance range based on the fact that the airspeed and propeller angle of the aircraft indicate an increase in airflow along the edge.

12. The electrical system according to any one of claims 1 to 11, wherein the at least one propeller parameter indicates at least one of a propeller speed range to be avoided, a propeller speed range to be maintained, or a target propeller speed outside the propeller speed range to be avoided.

13. The aforementioned at least one propeller parameter indicates the respective target propeller speed for each propeller of the aircraft. Determining the respective commands for each propeller of the aircraft to satisfy the determined thrust based on the at least one propeller parameter is: The electrical system according to any one of claims 1 to 12, comprising applying the propeller parameters indicating each target propeller speed as attractors in an assignment function, the assignment function determining a combination of propeller commands to achieve the determined thrust.

14. The electrical system according to any one of claims 1 to 13, wherein the at least one processor is further configured to change the at least one propeller parameter based on at least one of the aircraft's airspeed or propeller angle.

15. The aforementioned at least one processor is The first sensor data indicating the airspeed of the aircraft is received, Receiving second sensor data indicating the propeller angle, Based on the first sensor data and the second sensor data, the at least one propeller parameter is changed. The electrical system according to any one of claims 1 to 14, further configured as follows.

16. The aforementioned at least one propeller parameter is torque, The electrical system according to any one of claims 1 to 15, wherein the at least one processor is further configured to determine the at least one propeller parameter based on the relationship between propeller speed and torque, the relationship between propeller speed and torque changes based on the flight phase of the aircraft.

17. The aforementioned at least one processor is The sensor receives sensor data indicating the propeller speed of each propeller of the aforementioned aircraft. Based on the at least one propeller parameter and the sensor data for the corresponding propeller, the command for each propeller of the aircraft is determined. The electrical system according to any one of claims 1 to 16, further configured as follows.

18. The aforementioned at least one processor is The sensor receives data indicating the propeller speed of each propeller. Based on the received sensor data for the corresponding propeller, adjusting the determined command and controlling each propeller of the aircraft is done based on the adjusted command. The electrical system according to any one of claims 1 to 17, further configured as follows.

19. The aforementioned at least one propeller parameter includes at least two parameters, The first parameter indicates the propeller speed avoidance range. The second parameter indicates the difference in propeller speed applied between the propellers of the aircraft. The electrical system according to any one of claims 1 to 18, wherein determining the respective commands for each propeller of the aircraft includes prioritizing the first parameter over the second parameter.

20. The at least one propeller parameter changes based on the flight conditions of the aircraft. The aforementioned at least one processor is The electrical system according to any one of claims 1 to 19, further configured to repeatedly retrieve the at least one propeller parameter during the flight of the aircraft and to control the aircraft based on the at least one propeller parameter.

21. The electrical system according to any one of claims 1 to 20, wherein the propeller parameters are based on experimentally testing or modeling the effect of propeller speed on the structural vibration response of at least one of the aircraft body, the aircraft boom, the aircraft propeller, or the aircraft wing.

22. The electrical system according to any one of claims 1 to 21, wherein the propeller parameter indicates the standard deviation required between the propeller speeds.

23. The aforementioned at least one processor is Torque values ​​are randomly assigned to each of the propellers to satisfy the determined thrust. The random assignment of propeller torque determines whether the required standard deviation of the propeller speed is met. If it is determined that the aforementioned standard deviation of the propeller speed is not met, the aforementioned random assignment of torque values ​​is repeated. When it is determined that the aforementioned standard deviation of the propeller speed is satisfied, the respective commands for each propeller of the aircraft are determined. The electrical system according to claim 22, further configured as follows.

24. The electrical system according to any one of claims 1 to 23, wherein each of the aforementioned commands is determined to maintain the trim state of the aircraft.

25. The aforementioned at least one processor is A second propeller parameter is taken, and the second propeller parameter is determined to reduce the noise emission of the aircraft. It is determined whether the aircraft can be controlled according to the second propeller parameter without increasing the structural vibration response of the aircraft. If it is determined that the structural vibration response in the aircraft will not increase, then the propellers of the aircraft are controlled based on the second propeller parameter. The electrical system according to any one of claims 1 to 24, further configured as follows.

26. It is an aircraft, It comprises at least one processor, and the at least one processor is Receive pilot input indicating the commanded aircraft status, Determine the aircraft thrust required to achieve the commanded aircraft state, At least one propeller parameter associated with propeller speed is taken, and the propeller parameter is determined to reduce the structural vibration response in the aircraft. Based on the at least one propeller parameter, a command is determined for each propeller of the aircraft to achieve the determined aircraft thrust. Based on the corresponding commands, each propeller of the aircraft is controlled, An aircraft configured in such a way.

27. A method for controlling an aircraft, Receiving pilot input indicating the commanded aircraft status, To determine the aircraft thrust required to achieve the commanded aircraft state, Extracting at least one propeller parameter associated with propeller speed, wherein the propeller parameter is determined to reduce the structural vibration response in the aircraft. Based on the at least one propeller parameter, determine the respective commands for each propeller of the aircraft to achieve the determined aircraft thrust, A method comprising controlling each of the propellers of the aircraft based on the corresponding commands.

28. A computer-readable storage medium storing instructions, wherein when an instruction is executed by at least one processor, the instructions are stored in the at least one processor. It receives pilot input indicating the commanded aircraft status, Determine the aircraft thrust required to achieve the commanded aircraft state. At least one propeller parameter associated with propeller speed is extracted, and the propeller parameter is determined to reduce the structural vibration response in the aircraft. Based on the at least one propeller parameter, a command for each propeller of the aircraft is determined to achieve the determined aircraft thrust. Based on the corresponding commands, each propeller of the aircraft is controlled. Computer-readable storage medium.

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