A composite manned spacecraft and its flight control method

Abstract

The application discloses a composite manned aircraft and a flight control method thereof, and belongs to the technical field of general aviation aircrafts. The aircraft comprises a distributed electric multi-rotor system serving as a main propulsion system and a large-rotor system arranged above the distributed electric multi-rotor system. The large-rotor system has at least a passive autorotation mode. In a cruising flight stage, the large-rotor system works in the passive autorotation mode, utilizes a forward airflow to generate auxiliary lift, reduces energy consumption of the main propulsion system and prolongs a cruising range. When a main propulsion system failure is detected, the large-rotor system keeps or enters the passive autorotation mode, utilizes a descending airflow of the aircraft to drive a large propeller to continuously rotate to generate lift, thereby controls a descending speed of the aircraft and realizes safe landing. The application innovatively applies the autorotation glide principle to an electric vertical take-off and landing aircraft, provides a safe mechanism capable of realizing controllable forced landing at a low altitude without additional energy, and significantly improves flight safety.

Description

Technical Field

[0001] This invention relates to the field of general aviation aircraft technology, and in particular to a composite safe manned aircraft and its corresponding flight control method. Background Technology

[0002] Personal low-altitude mobility vehicles, especially electric vertical takeoff and landing (eVTOL) aircraft, are emerging as a solution to urban traffic congestion. However, safety and range are the two core technological bottlenecks that limit their widespread adoption.

[0003] Current safety systems for manned aircraft primarily rely on preventative measures and emergency response. The mainstream emergency measure is whole-aircraft parachute deployment. However, this approach has fundamental flaws: First, personal aircraft typically fly at low altitudes; in the event of a malfunction, the extremely short drop window is insufficient for a conventional parachute to fully deploy and provide effective cushioning, rendering low-altitude rescue essentially ineffective. Second, whole-aircraft parachutes bind the occupants to the damaged fuselage and potentially still-spinning rotors, greatly increasing the risk of secondary injuries during the descent.

[0004] On the other hand, pure electric multi-rotor aircraft generally suffer from short range due to the energy density limitations of current battery technology. While traditional fuel-powered autogyros have longer ranges, their complex power systems, high costs, pollution, and inability to take off and land vertically make them unsuitable as personal urban commuting vehicles.

[0005] Therefore, existing technologies have always lacked an effective technical solution that can provide personal low-altitude aircraft with a safe guarantee of low-altitude availability and controlled emergency landing in the event of main propulsion system failure, while also improving endurance. Summary of the Invention

[0006] The purpose of this invention is to provide a composite safe manned aircraft and a corresponding flight control method, which aims to solve the technical problems of existing electric multi-rotor manned aircraft lacking an effective low-altitude safe landing mechanism when the main propulsion system fails, as well as insufficient endurance.

[0007] To achieve the above objectives, the present invention provides a composite safe manned aircraft, comprising: a distributed electric multi-rotor system configured as a main propulsion system to provide power for vertical takeoff and landing and cruise flight; and a large rotor system disposed above the distributed electric multi-rotor system, which includes a large propeller; wherein the large rotor system has at least a passive autorotation mode, in which the large propeller can passively rotate under the action of the relative airflow generated by the forward movement of the aircraft, thereby generating auxiliary lift; when the main propulsion system experiences power failure, the large rotor system maintains or enters the passive autorotation mode, causing the large propeller to continuously autorotate under the drive of the descent airflow of the aircraft to generate lift, thereby controlling the descent speed of the aircraft and achieving a safe landing.

[0008] This invention innovatively applies the principle of autorotation descent to the field of electric vertical takeoff and landing (eVTOL) aircraft. By employing a large-sized rotor system independent of the main propulsion system, this invention utilizes a large rotor with a large diameter and optimized airfoil, capable of capturing sufficient kinetic energy to generate considerable lift during passive rotation. When the main propulsion system (distributed electric multi-rotor system) fails, the aircraft begins to descend under gravity. At this time, the large rotor continues to autorotate under the drive of the oncoming updraft, converting the aircraft's gravitational potential energy into the rotor's rotational kinetic energy, thereby generating the lift required to maintain a controlled descent. This mechanism requires no additional energy input or complex pitch control mechanisms; it achieves a safe low-altitude emergency landing solely through the passive autorotation of the large rotor, fundamentally solving the technical challenge of existing eVTOL systems lacking reliable safety guarantees in low-altitude emergency scenarios.

[0009] Preferably, the large rotor system also has an active electric mode and can switch between the active electric mode and the passive self-rotation mode; in the active electric mode, the large rotor system actively drives the large propeller to rotate to generate lift through a drive device.

[0010] Optionally, the large rotor system includes: a large propeller; a drive unit configured to drive the large propeller; and a control module configured to control the operation of the drive unit to switch the large rotor system between the active electric mode and the passive autorotation mode.

[0011] Optionally, the drive device is a three-phase asynchronous motor.

[0012] Optionally, the three-phase asynchronous motor is a disc-type three-phase asynchronous motor.

[0013] Optionally, the control module is configured to: when the aircraft is in the passive autorotation mode, keep the stator winding of the drive device in an open circuit state.

[0014] Optionally, the control module is a three-phase controllable relay module.

[0015] Optionally, the control module is further configured to short-circuit the three-phase stator leads of the drive device to apply electromagnetic braking to the large propeller.

[0016] Optionally, the distributed electric multirotor system includes: a fuselage; at least four arms extending from the fuselage; and a pair of coaxial, counter-rotating upper and lower propellers disposed on each of the arms.

[0017] Optionally, the arm is configured to fold around its connection with the fuselage.

[0018] Optionally, it also includes a vertical arm extending upward from the top of the aircraft fuselage; wherein the large rotor system is mounted on the fuselage via the vertical arm.

[0019] This invention also provides a flight control method for a composite safe manned aircraft, the aircraft including a distributed electric multi-rotor system as the main propulsion system and a large rotor system, the large rotor system including a large propeller. The method includes: during the cruise flight phase, operating the large rotor system in a passive autorotation mode to utilize the airflow generated by the forward movement of the aircraft to passively rotate the large propeller and generate auxiliary lift, thereby reducing the energy consumption of the main propulsion system; and when a power failure is detected in the main propulsion system, maintaining or entering the passive autorotation mode of the large rotor system to utilize the descent airflow of the aircraft to drive the large propeller to continuously autorotate, generating lift to control the descent speed of the aircraft, thereby achieving a safe landing.

[0020] Optionally, the large rotor system further includes a motor for driving the large propeller, and the step of operating the large rotor system in the passive self-rotation mode includes: opening the stator windings of the motor.

[0021] Optionally, it also includes: after the aircraft lands, short-circuiting the three-phase stator leads of the motor to brake the large rotor system.

[0022] Optionally, the large rotor system also has an active electric mode, and the method further includes:

[0023] During the takeoff and / or landing phases of the aircraft, the large rotor system is switched to the active electric mode to actively drive the large propeller to rotate and generate lift, assisting the main propulsion system in vertical takeoff and landing.

[0024] Optionally, it also includes: when a power failure is detected in the main propulsion system, if the current flight state meets the preset active intervention conditions, the large rotor system is switched from the passive autorotation mode to the active electric mode, and the lift is increased by actively driving the large rotor system to rotate, so as to further reduce the descent speed of the aircraft.

[0025] Optionally, the step of detecting a power failure in the main propulsion system includes: real-time monitoring of the deviation between the speed feedback signal of each motor in the distributed electric multi-rotor system and the target speed command value; determining that the main propulsion system has experienced a power failure when the deviation exceeds a first preset threshold and persists for a first preset time; and / or real-time monitoring of the drive current feedback signal of each motor in the distributed electric multi-rotor system; determining that the main propulsion system has experienced a power failure when the expected current corresponding to the target speed command value exceeds a predetermined proportion of the rated current and the actual current feedback value remains below a second preset threshold and persists for a second preset time.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. Improved flight safety: By adding an independent, large-sized rotor system, which possesses at least a passive autorotation mode, the aircraft begins to descend under gravity when the distributed electric multi-rotor system, which is the main propulsion system, fails. Driven by updrafts, the large propeller passively autorotates, converting gravitational potential energy into the rotor's rotational kinetic energy and generating sufficient lift. This transforms the aircraft from a catastrophic "hard fall" into a controllable "autorotation descent" forced landing. This mechanism requires no additional energy input or complex pitch control mechanisms, making it particularly suitable for low-altitude emergency scenarios and solving the core safety problem of the lack of reliable emergency response measures in low-altitude environments.

[0028] 2. Extended flight range: During normal cruise flight, by operating the large rotor system in passive autorotation mode, auxiliary lift is generated by passive rotation using the forward airflow. This process does not consume electrical energy, which is equivalent to adding a highly efficient "glider" to the aircraft, thereby effectively reducing the energy consumption of the main propulsion system and significantly extending the flight range of the aircraft.

[0029] 3. Optional active emergency boosting means are provided: In the preferred implementation, the large rotor system can also switch between passive autorotation mode and active electric mode. When the lift generated by passive autorotation is insufficient to meet the emergency landing requirements (e.g., under heavy load or extreme attitude conditions), the active electric mode can be activated, whereby the drive unit actively drives the large propeller to rotate, actively providing additional lift, further reducing the descent speed, and improving the safety margin in emergency scenarios.

[0030] 4. Improved system operating efficiency and reliability: By using a disc-type three-phase asynchronous motor as the drive device for the large rotor system and opening its stator winding in passive self-rotation mode, the characteristics of this type of motor, which has no permanent magnets and no inherent magnetic reluctance torque when open-circuited, are utilized, resulting in a lower starting wind speed and higher aerodynamic efficiency for passive self-rotation, which well matches the needs of both active drive and passive self-rotation modes.

[0031] 5. Improved safety after landing: By short-circuiting the three-phase stator leads of the drive unit after landing, the large propeller can be braked by electromagnetic damping, which can quickly stop its rotation and avoid the safety hazards caused by the propeller continuing to rotate due to inertia or ground wind. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the overall structure of the composite safe manned aircraft according to an embodiment of the present invention.

[0034] Figure 2 This is a top view of the composite safe manned aircraft according to an embodiment of the present invention.

[0035] Figure 3 This is a front view of the composite safe manned aircraft according to an embodiment of the present invention.

[0036] Figure 4 This is a schematic diagram of the composite safe manned aircraft in the folded arm state according to an embodiment of the present invention.

[0037] Figure 5 This is a partial structural diagram of the folded arm in an embodiment of the present invention.

[0038] Figure 6 This is a schematic diagram of the control principle of the large rotor system according to an embodiment of the present invention.

[0039] Figure 7 This is a schematic diagram of the flight and emergency operation method according to an embodiment of the present invention.

[0040] In the diagram: 1-Cockpit, 2-Fuselage, 3-Arm, 4-Upper Propeller, 5-Upper Drive Motor, 6-Upright Arm, 7-Large Propeller, 8-Disc Three-Phase Asynchronous Motor, 9-Lower Propeller, 10-Lower Drive Motor, 11-Fixing Mechanism, 12-Seat, 13-Mounting Base, 14-First Mounting Hole, 15-Second Mounting Hole, 16-Connector, 30-Three-Phase Controllable Relay Module, 31-Airborne Main Power Supply, 32-Variable Frequency Drive Power Supply. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Unless otherwise defined, all technical and scientific terms used in the embodiments of this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in the embodiments of this invention is for descriptive purposes only and is not intended to limit the invention.

[0043] Before providing a further detailed description of the embodiments of the present invention, some of the nouns and terms involved in the embodiments of the present invention will be explained, and the nouns and terms involved in the embodiments of the present invention shall be interpreted as follows.

[0044] (1) Active electric mode: This refers to a working mode of the large rotor system. In this mode, the control module connects the power supply of the drive device and actively drives the large propeller to rotate to generate controllable lift. This mode is mainly used for auxiliary stabilization during the take-off and landing phases of the aircraft, or as a backup power source to further control the descent speed of the aircraft when the main propulsion system fails and the lift generated by the passive autorotation mode is insufficient to meet the emergency landing requirements.

[0045] (2) Passive Autorotation Mode: Also known as wind-driven mode or autorotation descent mode, this refers to a working mode of the large rotor system. In this mode, the large propeller passively rotates under the drive of airflow to generate lift. During cruise flight, the large propeller passively rotates under the influence of the relative airflow generated by the aircraft's forward movement, generating auxiliary lift in a zero-energy manner, thereby extending the aircraft's range. In emergency scenarios where the main propulsion system fails, the large propeller continues to autorotate under the drive of the updraft generated by the aircraft's descent, converting gravitational potential energy into rotational kinetic energy and generating lift, thereby achieving a controllable forced landing.

[0046] (3) Electromagnetic braking: refers to an operation used to slow down or stop the rotation of a large propeller. By short-circuiting the three-phase stator leads of the drive unit through the control module, a strong reverse electromagnetic damping torque is formed in the short-circuit circuit by the induced electromotive force generated by the rotation of the motor, thereby realizing the rapid braking of the large propeller.

[0047] (4) Disc-type three-phase asynchronous motor: This refers to a special type of motor in which the stator and rotor are arranged parallel to each other along the axial direction in a disc shape. The rotor is a squirrel-cage structure without permanent magnets. The magnetic field of the rotor depends entirely on the AC current flowing through the stator windings for excitation. When the motor is off, there is no current in the stator, and there is no main magnetic field inside the entire motor. The rotor simply rotates in the air with the squirrel-cage bars, and there are no magnetic lines of force to cut, so no induced current is generated and there is no electromagnetic resistance. It is very suitable for applications that require switching between active drive and passive rotation.

[0048] Please see Figures 1 to 7 This invention provides a composite safe manned aircraft and its flight control method, aiming to solve the core technical problems of existing electric vertical takeoff and landing (eVTOL) aircraft, such as the lack of a low-altitude safe landing mechanism in the event of complete failure of the main propulsion system, and the insufficient endurance due to limitations in battery energy density. This invention combines a distributed electric multi-rotor system responsible for the main flight maneuvers with a large rotor system that provides range extension and emergency response capabilities through an innovative composite power layout. This constructs a reliable safety assurance system and significantly improves the aircraft's endurance without sacrificing the advantages of electric multi-rotor aircraft, such as vertical takeoff and landing and maneuverability.

[0049] The core of the technical solution disclosed in this invention lies in proposing a composite safe manned aircraft, comprising a distributed electric multi-rotor system and a large rotor system. The distributed electric multi-rotor system is configured as the main propulsion system, providing power for the aircraft's main flight maneuvers such as takeoff, climb, hovering, cruise, and landing. The large rotor system is positioned above the distributed electric multi-rotor system (e.g., stacked on top of it). This stacked layout aims to, on the one hand, place the large rotor system in a relatively clean airflow environment above, which is beneficial for its aerodynamic efficiency in different modes; on the other hand, it integrates the two systems vertically, resulting in a compact overall structure. A key characteristic of this large rotor system is that it has at least one passive autorotation mode. In passive autorotation mode, the large propeller 7 can passively rotate under airflow to generate lift. This passive autorotation capability is the core technical foundation for this invention to solve the two major contradictions of safety and endurance in the prior art. By utilizing the passive autorotation mode in different flight phases, the aircraft can balance efficiency and safety, achieving comprehensive performance superior to some existing technical solutions.

[0050] Furthermore, in a preferred embodiment, to achieve more diverse functions, the large rotor system can also switch between an active electric mode and the passive autorotation mode. Structurally, the large rotor system includes a large propeller 7, a drive unit, and a control module. The large propeller 7 has a large diameter and an optimized airfoil, designed to generate significant lift even at low speeds, which is crucial for passive autorotation (especially during emergency landings). The drive unit is configured to drive the large propeller 7 to rotate. The control module is configured to control the operation of the drive unit, enabling the large rotor system to switch between the active electric mode and the passive autorotation mode. This structural decomposition clarifies the core hardware unit for achieving dual-mode functionality: the control module manages the electrical state of the drive unit, thereby changing the macroscopic operating mode of the entire large rotor system, realizing the transformation from control commands to physical actions.

[0051] In a more preferred embodiment, the drive device is a three-phase asynchronous motor. The choice of a three-phase asynchronous motor, rather than the permanent magnet synchronous motor commonly used in multi-rotor aircraft, is a key technical consideration of this invention. The design purpose is that the rotor structure of a three-phase asynchronous motor (such as a squirrel-cage rotor) does not contain permanent magnets, giving it a natural low-damping advantage in passive rotation mode. By using a three-phase asynchronous motor, the technical problem of inherent reluctance torque (cogging torque) generated during passive rotation due to the interaction between the permanent magnets and the stator core, which is present in permanent magnet synchronous motors, is solved. This significantly improves the aerodynamic efficiency of passive rotation—a low-damping characteristic crucial in both cruise range extension and emergency landing scenarios.

[0052] It is understood that the drive device is not limited to a three-phase asynchronous motor. For example, the drive device may employ a mechanism that combines a permanent magnet synchronous motor with a clutch. In passive self-rotation mode, the clutch disengages from the main shaft of the large propeller 7. When switching to active electric mode, the clutch is connected to the main shaft of the large propeller 7.

[0053] Furthermore, the three-phase asynchronous motor is preferably a disc-type three-phase asynchronous motor 8. The disc structure, where the stator and rotor of the motor are arranged parallel along the axial direction, has a shorter axial dimension and a larger diameter compared to traditional radial magnetic field motors, enabling it to provide sufficient torque within a limited space. More importantly, the disc-type three-phase asynchronous motor 8's characteristics of having no permanent magnets and low reluctance loss perfectly match the dual-mode operation requirements of this invention. Its structural characteristics are key to achieving efficient passive rotation, constituting a preferred embodiment of this invention.

[0054] In another preferred embodiment, the implementation of the passive rotation mode is defined from the perspective of control logic. The control module is configured to keep the stator winding of the drive device in an open-circuit state when the aircraft is in the passive rotation mode. The principle of this operation is that when the stator winding is open-circuited, even if the rotor rotates with the large propeller 7, a closed current loop will not be formed in the stator winding, thus preventing the generation of electromagnetic induction torque. Therefore, the motor applies only a small amount of bearing mechanical friction resistance to the rotation of the large propeller 7, minimizing energy loss and enabling the large propeller 7 to start and maintain rotation under only weak relative airflow, achieving efficient energy capture.

[0055] To achieve the aforementioned open-circuit control, the control module can be specifically implemented in hardware as a three-phase controllable relay module 30. The input terminal of this three-phase controllable relay module 30 is connected to the power supply system, and the output terminal is connected to the motor stator winding. By controlling the on / off state of the relay, the stator winding can be easily connected to the power supply (active motor mode) or completely disconnected (passive self-rotation mode). Using a relay module is a mature, reliable, and cost-effective technical solution that ensures the determinism and safety of electrical connections during critical mode switching processes.

[0056] Furthermore, in a safer implementation, the control module is also configured to short-circuit the three-phase stator leads of the drive unit to apply electromagnetic braking to the large propeller 7. This function is designed to address the safety hazard caused by the large propeller 7 rotating for an extended period due to inertia or ground winds after the aircraft lands. The principle is that when the three-phase stator leads are short-circuited, the induced electromotive force generated by the rotating rotor cutting magnetic lines of force produces a large short-circuit current in the short-circuit loop, thereby forming a strong reverse electromagnetic damping torque that allows the large propeller 7 to stop rotating rapidly within a short time. By adding this electromagnetic braking function, the safety of the aircraft is improved in scenarios such as ground maintenance and passenger boarding / disembarking.

[0057] Returning to the overall layout of the aircraft, in another parallel preferred embodiment, the distributed electric multirotor system, which serves as the main propulsion system, is specifically structurally defined. This system includes a fuselage 2, at least four arms 3 extending from the fuselage 2, and a pair of coaxial, counter-rotating upper propeller 4 and lower propeller 9 mounted on each of the arms 3. This "multi-arm" and "coaxial counter-rotating propeller" layout, compared to a single-rotor or conventional quadcopter layout, can provide stronger lift redundancy and attitude control capabilities by increasing the number of propellers without significantly increasing the overall footprint, thus improving the stability and safety of the aircraft.

[0058] To improve the portability and storage convenience of the aircraft, in one optional embodiment, the arm 3 is configured to fold around its connection point with the fuselage 2. This design significantly reduces the space occupied by the aircraft during parking and transportation when not in use, and has important practical value for applications as a personal transportation tool.

[0059] To achieve a reliable connection between the large rotor system and the fuselage and optimize the aerodynamic layout, this invention also provides a preferred mounting structure. This structure includes a vertical arm 6 extending upwards from the top of the fuselage 2 of the aircraft, through which the large rotor system is mounted to the fuselage 2. Raising the large propeller 7 via the vertical arm 6 effectively reduces airflow interference between it and the distributed multi-rotor system below and the fuselage 2 during operation, ensuring the aerodynamic efficiency of each component, while also providing a clear view and sensor working space for the systems below.

[0060] Accordingly, this invention also provides a flight control method for a composite safety manned aircraft, which transforms the structural advantages of the aforementioned device into practical flight benefits. The method includes: during the cruise phase, operating the large rotor system in a passive autorotation mode to utilize the airflow generated by the aircraft's forward movement to passively rotate the large propeller and generate auxiliary lift, thereby reducing the energy consumption of the main propulsion system. The purpose of this is to share some of the aircraft's weight without consuming additional electrical energy, thereby reducing the power output of the main propulsion system and directly extending the flight range. Simultaneously, the method also includes: when a power failure of the main propulsion system is detected, maintaining or entering the passive autorotation mode of the large rotor system to utilize the descending airflow to drive the large propeller to continuously autorotate, generating lift to control the aircraft's descent speed, thereby achieving a safe landing. This step embodies the core safety concept of this invention—introducing the autorotation glide principle into an electric vertical takeoff and landing (EVTOL) aircraft, enabling the aircraft to achieve a controlled forced landing without external energy input when power is completely lost, providing effective low-altitude safety assurance.

[0061] Furthermore, in the flight control method, the specific steps for operating the large rotor system in the passive autorotation mode include: opening the stator windings of the motor. This corresponds to the control logic in the aforementioned device embodiment and forms the electrical operational basis for achieving low-damping passive autorotation.

[0062] Furthermore, to improve safety management throughout the entire flight lifecycle, the method also includes: short-circuiting the three-phase stator leads of the motor after the aircraft lands to brake the large rotor system. This step corresponds to the electromagnetic braking function of the device, ensuring the safety of the aircraft on the ground and forming a complete safety closed loop from takeoff, cruise, emergency response to post-landing handling.

[0063] In a preferred embodiment, the large rotor system also has an active electric mode, and the method further includes: during the takeoff or landing phase of the aircraft, switching the large rotor system to the active electric mode to actively drive the large propeller to rotate and generate lift, assisting the main propulsion system in vertical takeoff and landing. This preferred step allows the aircraft to utilize the additional lift provided by the large rotor system during takeoff and landing, improving takeoff and landing performance.

[0064] In another preferred embodiment, the method further includes: upon detecting a power failure in the main propulsion system, if the current flight state meets preset active intervention conditions (e.g., large aircraft load, severe attitude tilt, or excessive descent speed causing passive autorotation to fail to provide sufficient lift), switching the large rotor system from the passive autorotation mode to an active electric mode, and actively driving the large rotor system to rotate to increase lift, thereby further reducing the aircraft's descent speed. This preferred step provides additional safety redundancy, allowing the active electric mode to serve as an effective supplement to passive autorotation under extreme conditions, further improving the success rate of emergency landings.

[0065] The following will be combined with the appendix Figures 1 to 7 The present invention will now describe in more detail the composite safe manned aircraft in its embodiments. It should be understood that these embodiments are merely examples and are not intended to limit the scope of the invention.

[0066] Please see Figure 1 and Figure 3 This illustration demonstrates the overall structure of a composite safe manned aircraft according to a preferred embodiment of the present invention. The aircraft comprises an integrated fuselage 2 and a cockpit 1. The cockpit 1 has seats 12 for one or more passengers, accessible via an openable door. Headlights for nighttime or low-light flight are located at the front of the cockpit 1. Landing gear is mounted on the bottom of the fuselage 2 for supporting the aircraft during parking, takeoff, and landing. A signal antenna may also be mounted on the top of the fuselage 2 for communication with ground control stations or other aircraft.

[0067] The aircraft's main propulsion system is a distributed electric multirotor system. For example... Figure 1 and Figure 3As shown, the system includes four arms 3 extending from the fuselage 2, arranged in a cross shape along the fuselage. Each arm 3 has a power unit at its end. Specifically, a mounting base 13 is provided at one end of each arm 3, and an upper drive motor 5 and a lower drive motor 10 are fixed to the upper and lower ends of the mounting base 13, respectively. The upper drive motor 5 drives the upper propeller 4 to rotate, and the lower drive motor 10 drives the lower propeller 9 to rotate. In a preferred embodiment, both the upper drive motor 5 and the lower drive motor 10 are high-efficiency permanent magnet synchronous motors. On the same arm 3, the upper propeller 4 and the lower propeller 9 rotate in opposite directions, forming a coaxial counter-rotating propeller structure, which can effectively counteract counter-torque and improve the control stability and power efficiency of the aircraft.

[0068] The core of this invention, namely the large rotor system, is stacked on top of the aforementioned distributed electric multi-rotor system. For example... Figure 1 and Figure 3 As shown, a vertical arm 6 extends upward from the center of the top of the fuselage 2, and the large rotor system is mounted on the top of the vertical arm 6. The system mainly includes a large propeller 7 and a disc-type three-phase asynchronous motor 8, which drives the large propeller 7. This mounting method via the vertical arm 6 makes the working area of ​​the large propeller 7 much higher than that of the upper propeller 4 and lower propeller 9 below, avoiding complex airflow interference.

[0069] Now combine Figure 6 and Figure 7 The working principle and methods of the aircraft will be explained. Figure 6 This is a schematic diagram illustrating the control principle of a large rotor system. Figure 7 This is a flowchart illustrating flight and emergency operation procedures.

[0070] During the takeoff phase (S301), the pilot activates the distributed electric multirotor system, with all eight propellers (upper propeller 4 and lower propeller 9) operating simultaneously to provide powerful vertical lift, enabling the aircraft to take off and climb vertically. During this phase, if the aircraft is equipped with an active electric mode, the large rotor system can be driven at low speed by a disc-type three-phase asynchronous motor 8 in active electric mode to provide additional attitude stability or lift assistance.

[0071] When the aircraft enters the cruise phase (S302), the distributed electric multirotor system adjusts the rotational speeds of each propeller to provide the primary cruise thrust. At this time, the control system switches the main rotor system to passive autorotation mode. Specifically, as follows... Figure 6As shown, the three-phase controllable relay module 30 disconnects from the frequency converter drive power supply 32, putting the stator windings of the disc-type three-phase asynchronous motor 8 in an open-circuit state. Since the disc-type three-phase asynchronous motor 8 itself has no permanent magnets and extremely low reluctance torque, the large propeller 7 can passively rotate with minimal resistance under the influence of the relative airflow generated by the aircraft's forward movement, producing considerable auxiliary lift. This lift shares the total weight of the aircraft, allowing the distributed electric multi-rotor system below to reduce its power output, thereby significantly saving energy from the onboard main power supply 31 and effectively extending the aircraft's range.

[0072] Throughout the flight, the flight control system continuously monitors the operating status of the main propulsion system (i.e., the distributed electric multirotor system) (S303).

[0073] In one specific implementation, to reliably trigger emergency safety procedures, the aircraft further includes a flight control system configured to monitor the operational status of the distributed electric multirotor system (i.e., the main propulsion system) in real time. The determination of "detecting a failure of the main propulsion system" is not based on a single source, but rather on real-time monitoring and logical fusion of multiple key physical quantities.

[0074] Specifically, the flight control system monitors at least the following three types of parameters:

[0075] Motor speed feedback signal: Each of the upper drive motor 5 and lower drive motor 10 is equipped with a speed sensor (e.g., a Hall sensor or photoelectric encoder). The flight control system acquires the actual speed feedback value of each motor in real time and compares it with the target speed command value corresponding to the current attitude control command. When the actual speed feedback value of a certain motor continuously deviates from the target speed command value by more than a first preset threshold (e.g., the absolute value of the deviation is greater than 30% of the target value) and the duration exceeds a first preset time (e.g., lasting 0.5 seconds), the motor is determined to be in a failed state. The setting of this threshold and time eliminates instantaneous interference such as airflow disturbances, ensuring the stability of the criterion.

[0076] Motor drive current feedback signal: The electronic speed controllers of each of the upper drive motors 5 and lower drive motors 10 report the actual sampled values ​​of their bus current or phase current to the flight control system in real time. When the target speed command value issued by the flight control system requires the motor to output high power (e.g., the expected current corresponding to the command value is greater than 50% of the rated current), but the actual sampled current feedback value is continuously lower than the second preset threshold (e.g., lower than 10% of the rated current) for a second preset time (e.g., for 0.3 seconds), it is determined that the motor has failed due to an electrical open circuit or a drive circuit failure.

[0077] Battery bus voltage and current signals of the airborne main power supply 31: The flight control system monitors the bus voltage and total output current of the airborne main power supply 31 in real time through voltage and current sensors. The flight control system calculates the rate of decrease of the bus voltage (dV / dt) per unit time. When the bus voltage decrease exceeds a third preset threshold (e.g., the voltage decrease exceeds 15% of the total voltage) within a third preset time (e.g., 1 second), and the bus output current does not increase significantly (or decreases abnormally), it is determined that a serious failure has occurred in the battery system or the main power distribution network, resulting in the main propulsion system being unable to obtain sufficient power.

[0078] In a more preferred logical decision algorithm, the flight control system does not trigger the emergency mode based on the anomaly of a single parameter. Instead, it executes a "multi-sensor data fusion and confidence voting" mechanism to distinguish between transient sensor noise and genuine physical failure, effectively preventing false triggering. The specific decision logic is as follows:

[0079] Failure confidence accumulation rule:

[0080] When the above-mentioned first type (speed deviation) parameter abnormality is triggered, it is counted as a "high confidence failure event", and the failure confidence counter is incremented by 3 points.

[0081] When the above-mentioned second type (current-command mismatch) parameter abnormality is triggered, it is counted as a "medium confidence failure event", and the failure confidence counter is incremented by 2 points.

[0082] When the above-mentioned third type (bus voltage drop) parameter abnormality is triggered, it is counted as a "critical failure event", and the failure confidence counter is directly incremented by 5 points.

[0083] If the corresponding sensor parameters return to normal, the accumulated confidence score for the corresponding event will be automatically deducted.

[0084] Triggering conditions:

[0085] The flight control system updates the failure confidence counter in each control cycle (e.g., every 10 milliseconds) and determines:

[0086] Condition A (Immediate Trigger): If the cumulative total score of the failure confidence counter reaches or exceeds 5 points within the fourth preset time (e.g., 0.2 seconds), the flight control system immediately determines that the main propulsion system has suffered an irreversible serious failure, regardless of the current flight status, and immediately and unconditionally enters step S304 (activating the electric mode of the large rotor system) – in the implementation scheme with only a passive autorotation mode, the passive autorotation emergency landing procedure is entered.

[0087] Condition B (Redundancy Confirmation Trigger): If the cumulative total score of the failure confidence counter reaches 3 points but is less than 5 points, a software timer is triggered for redundancy confirmation. If the above-mentioned abnormal state fails to resolve itself and the confidence score does not decrease within a fifth preset time (e.g., 1 second), the flight control system also determines that the main propulsion system has failed and enters emergency mode.

[0088] Exception protection logic: If the flight control system detects that the aircraft is in a low-altitude hovering or low-speed climb phase (e.g., altitude less than 10 meters and vertical speed less than 2 meters / second), in order to deal with the most dangerous near-ground failure scenario, the flight control system will lower the trigger threshold. At this time, if more than two motors are detected to have the above-mentioned first or second type of abnormality at the same time, it will be directly judged as a failure of the main propulsion system.

[0089] Through the aforementioned multi-dimensional and hierarchical monitoring methods combining hardware and logic, this invention achieves rapid, accurate, and interference-resistant detection of main propulsion system failures, providing a reliable technical prerequisite for timely initiation of passive autorotation emergency landing procedures or switching of the large rotor system to active electric mode, thereby fully disclosing the implementation path of the core safety functions of this invention.

[0090] Under normal circumstances (judged as "No"), the aircraft will continue to cruise until a normal landing. However, if a serious malfunction of the main propulsion system is detected, such as multiple motor failures or battery system power failure leading to complete or substantial loss of power (judged as "Yes"), the flight control system will immediately trigger the emergency safety procedure.

[0091] The core steps of the emergency procedure are: to put the large rotor system into a passive autorotation mode (if it is already in this mode, maintain it), using the updraft generated by the aircraft's descent to drive the large propeller 7 to continue autorotating. According to the principle of autorotation descent, the large propeller 7, driven by the airflow, converts the aircraft's gravitational potential energy into rotational kinetic energy, generating sufficient lift to balance some or most of the aircraft's weight. In a preferred embodiment (e.g....) Figure 6 As shown), the three-phase controllable relay module 30 keeps its stator windings in an open-circuit state (if the aircraft only has a passive autorotation mode) or, depending on the situation, switches to an active electric mode (if the aircraft is equipped with an active electric mode and meets the active intervention conditions). In passive autorotation mode, the flight control system can control the rotational speed of the large propeller 7 by adjusting the aircraft's pitch attitude (S305), so that it generates enough lift to balance or largely balance the aircraft's gravity. This will transform the aircraft from a catastrophic freefall state into a controllable, uniform or slowly accelerating descent state, thus giving the pilot or autopilot system valuable time and control capabilities to choose a suitable safe area for a forced landing and achieve a safe landing (S306), thereby providing reliable life protection for the occupants.

[0092] Furthermore, to enhance the safety of the aircraft throughout the entire ground operation, the control module of this invention also integrates an electromagnetic braking function. After the aircraft lands under normal or emergency conditions, to prevent the large propeller 7 from continuing to rotate due to inertia or wind force and posing a danger to personnel or equipment, the control system can instruct the three-phase controllable relay module 30 to directly short-circuit the stator three-phase leads of the disc-type three-phase asynchronous motor 8. For example... Figure 6 In the braking mode shown, the rotating motor rotor acts as a generator, generating a huge short-circuit current in the short-circuited stator windings. This creates a powerful electromagnetic damping torque, causing the large propeller 7 to stop rotating rapidly within seconds. This function corresponds to the post-landing braking step in the method claims, greatly improving ground safety.

[0093] In an alternative implementation, to improve the portability and storage convenience of the aircraft, arm 3 can be designed as a foldable structure. See also... Figure 4 and Figure 5 The figure illustrates the structure of the robotic arm in its folded state. One end of the robotic arm 3 is connected to a fixing mechanism 11 fixed to the body 2 via a hinge structure. When folded for storage, the robotic arm 3 can be retracted towards the body 2 around the hinge point. To ensure sufficient structural rigidity during use, the fixing mechanism 11 has a first mounting hole 14, and the robotic arm 3 has a corresponding second mounting hole 15. When the robotic arm 3 is extended to the working position, the first mounting hole 14 and the second mounting hole 15 are aligned, and a fastener (a bolt not shown in the figure) is passed through and locked to securely fix the robotic arm 3. In the folded state, to prevent the robotic arm from wobbling, an additional connector 16 can be used to temporarily lock the robotic arm 3 to the fixing mechanism 11. The locking holes at both ends of the connector 16 are aligned with the first mounting hole 14 and the second mounting hole 15, respectively. A pin passes through the first mounting hole 14 and the locking hole, and the second mounting hole 15 and the locking hole, respectively, to achieve temporary locking.

[0094] It should be noted that the specific configuration of the composite safe manned aircraft protected by this invention is not limited to the above embodiments. For example, the distributed electric multi-rotor system can have six or more arms, and the power unit on each arm can be a single propeller instead of a coaxial counter-rotating propeller. The core of this invention lies in setting up a large rotor system with at least a passive autorotation mode on top of any form of distributed electric multi-rotor system. This large rotor system utilizes its passive autorotation during the cruise phase to extend the range, and in the event of main propulsion system failure, it uses the autorotation glide principle to achieve a safe forced landing. This core technical solution can serve as a standardized safety and range extension module, adaptable to different configurations of electric vertical takeoff and landing (EVTOL) aircraft platforms.

[0095] In summary, this invention innovatively combines a distributed electric multi-rotor system with a large rotor system in a composite, layered layout. It creatively introduces the principle of autogyro gliding from the aviation field into electric vertical takeoff and landing (EVTOL) aircraft, successfully converting the fall energy of the aircraft in the event of power failure into controllable autogyro gliding energy. This enables safe low-altitude emergency landings without external energy input, overcoming the core technical bottleneck in the safety of existing personal low-altitude aircraft. Simultaneously, the passive autogyro of the large rotor system during the cruise phase generates auxiliary lift with zero energy consumption, significantly improving the aircraft's endurance. This invention not only provides a novel composite safe manned aircraft but, more importantly, offers a complete and effective safety solution for controllable emergency landings in low-altitude environments.

Claims

1. A composite safe manned aircraft, characterized in that, include: The distributed electric multirotor system is configured as the main propulsion system to provide power for vertical takeoff and landing and cruise flight. as well as A large rotor system, positioned above the distributed electric multi-rotor system, includes a large propeller; The large rotor system has at least a passive autorotation mode. In the passive autorotation mode, the large propeller can passively rotate under the action of the relative airflow generated by the forward movement of the aircraft, thereby generating auxiliary lift. When the main propulsion system fails, the large rotor system maintains or enters the passive autorotation mode, causing the large propeller to continuously rotate under the drive of the aircraft's descent airflow to generate lift, thereby controlling the aircraft's descent speed and achieving a safe landing.

2. The composite safe manned aircraft according to claim 1, characterized in that, The large rotor system also has an active electric mode and can switch between the active electric mode and the passive autorotation mode; in the active electric mode, the large rotor system actively drives the large propeller to rotate through the drive device to generate lift.

3. The composite safe manned aircraft according to claim 2, characterized in that, The large rotor system also includes: The drive unit is configured to drive the large propeller; and The control module is configured to control the operation of the drive unit to switch the large rotor system between the active electric mode and the passive autorotation mode.

4. The composite safe manned aircraft according to claim 3, characterized in that, The control module is configured to keep the stator winding of the drive device in an open circuit state when the aircraft is in the passive autorotation mode.

5. The composite safe manned aircraft according to claim 4, characterized in that, The control module is also configured to short-circuit the three-phase stator leads of the drive device to apply electromagnetic braking to the large propeller.

6. The composite safe manned aircraft according to claim 1, characterized in that, The distributed electric multi-rotor system includes: body; At least four arms extending from the fuselage; and A pair of coaxial, counter-rotating upper and lower propellers are mounted on each of the aforementioned arms.

7. The composite safe manned aircraft according to claim 6, characterized in that, The arm is configured to fold around its connection with the fuselage.

8. The composite safe manned aircraft according to claim 6, characterized in that, It also includes a vertical arm extending upward from the top of the aircraft fuselage; wherein the large rotor system is mounted on the fuselage via the vertical arm.

9. A flight control method for a compound safe manned aircraft, the aircraft comprising a distributed electric multi-rotor system as the main propulsion system and a large rotor system, the large rotor system comprising a large propeller, characterized in that, The method includes: During cruise flight, the large rotor system operates in passive autorotation mode, utilizing the airflow generated by the aircraft's forward movement to passively rotate the large propeller and generate auxiliary lift, thereby reducing the energy consumption of the main propulsion system; and When a power failure is detected in the main propulsion system, the large rotor system is kept in or enters the passive autorotation mode to use the downdraft of the aircraft to drive the large propeller to continue to rotate, generating lift to control the descent speed of the aircraft, thereby achieving a safe landing.

10. The flight control method according to claim 9, characterized in that, The large rotor system also has an active electric mode, and the method further includes: During the takeoff and / or landing phases of the aircraft, the large rotor system is switched to the active electric mode to actively drive the large propeller to rotate and generate lift, assisting the main propulsion system in vertical takeoff and landing.

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