An electrically driven flying car cross-domain motion control method and device

Abstract

The application relates to a kind of electric drive flying car cross-domain motion control method and device, wherein the method comprises: when being in flight state and switching to transition mode, receiving sensor information, extracting the distance from the ground based on the obtained sensor information;Whether the distance from the ground is less than the first set threshold, if yes, whether the distance from the ground is less than the second set threshold, if yes, based on pose oscillation compensation, vertical impact compensation and lateral motion compensation, transition strategy compensation input is generated, otherwise, based on lateral motion compensation, transition strategy compensation input is generated;According to the transition strategy compensation input, the system control input is corrected to obtain power distribution output, and each rotor is controlled based on the obtained power distribution output. Compared with the prior art, the application has the advantages of stable cross-domain control from flight state to land state by relying only on rotor control.

Description

Technical Field

[0001] This invention relates to the field of cross-domain control of flying cars, and in particular to a cross-domain motion control method and device for an electrically driven flying car. Background Technology

[0002] Flying cars and other general aviation equipment, with their high mobility (allowing for switching between land and air), strong terrain adaptability, and rapid deployment capabilities, can significantly reduce traffic congestion and improve travel and transportation efficiency. Furthermore, their flexibility and rapid response capabilities enable them to quickly reach work areas and provide services, making them highly valuable in military, rescue, and transportation fields. Multi-rotor flying cars, with their vertical takeoff and landing, simple control, and high mobility, can achieve rapid switching of working modes without terrain limitations, making them an important carrier for low-altitude economy and three-dimensional transportation.

[0003] The motion control of flying cars is divided into flight mode, land mode and transition mode. Motion stability is affected by many factors during driving, including the force conditions, structural layout, rotor parameters, drive motor performance and sensor characteristics in each mode. The transition process design will introduce additional impact and attitude control requirements, while also needing to consider the safety and driving comfort requirements under manned conditions.

[0004] Existing land-air mode switching and transition motion control schemes usually require additional mechanical structures, which can easily lead to problems such as increased control system complexity, slow switching process, increased energy consumption and increased ground control errors. Reducing takeoff and landing impacts and turbulence, and constructing safe and reliable cross-domain control schemes and manned safety control schemes are important issues and research directions for multi-rotor control. Summary of the Invention

[0005] The purpose of this invention is to provide a method and device for cross-domain motion control of an electrically driven flying car.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A cross-domain motion control method for an electrically driven flying car includes:

[0008] When in flight and switching to transition mode, it receives sensor information and extracts the distance to the ground based on the acquired sensor information;

[0009] Determine whether the distance from the ground is less than a first set threshold. If it is, determine whether the distance from the ground is less than a second set threshold. If it is, generate a transition strategy compensation input based on pose oscillation compensation, vertical impact compensation, and lateral motion compensation. Otherwise, generate a transition strategy compensation input based on lateral motion compensation.

[0010] The power distribution output is obtained by compensating the input of the transition strategy and correcting the system control input, and then the operation of each rotor is controlled based on the obtained power distribution output.

[0011] The power distribution output is:

[0012] U d (t)=u(t)+ε(t)

[0013] Among them: U d ε(t) is the power distribution output, u(t) is the system control input, and ε(t) is the transient strategy compensation input.

[0014] The transition strategy compensation input is:

[0015] ε(t)=Mx s (t)+Nn(t)+Kk(t)

[0016] Where: M is the trajectory compensation matrix, x s (t) is the pose sensor input, N is the oscillation compensation matrix, n(t) is the high-frequency oscillation signal, K is the impact compensation matrix, and k(t) is the impact input.

[0017] The process of acquiring the high-frequency oscillation signal includes:

[0018] The original oscillation signal is obtained based on the angular velocity;

[0019] The original oscillation signal is high-pass filtered to obtain a high-frequency oscillation signal.

[0020] The process of determining the vertical impact compensation includes:

[0021] Step S1-1: Considering that the wheel hubs do not land at the same time and that the compression of the wheel hubs and the shock absorption system is uneven, the theoretical and actual vertical impacts of the ground on each wheel hub are recorded as follows:

[0022]

[0023] Where: N d N is the theoretical vertical impact matrix. s f is the actual vertical impact matrix. wzd1 to f wzd4 The theoretical vertical impacts, f, caused by each wheel hub on the ground are respectively. wzs1 to f wzs4 These represent the actual vertical impacts caused by each wheel hub on the ground;

[0024] Step S1-2: Determine the torque of a single wheel hub vertical impact on the machine body as follows:

[0025]

[0026] Wherein: T w F is the torque synthesis matrix of the vertical force at the hub. wz The vertical force matrix of the wheel hub is τ. wzx Let τ be the x-axis component of the torque of the vertical impact on the center of mass of the wheel hub. wzy D1 and D2 are the y-axis component of the torque of the vertical impact of the hub on the center of mass, and the lateral and longitudinal distances from the hub to the center of mass of the machine body, respectively.

[0027] Step S1-3: Determine the torque of the multirotor lift about the center of mass:

[0028]

[0029] Where: τ x Let τ be the x-axis component of the rotor lift torque about the center of mass. y T is the y-axis component of the rotor lift torque about the center of mass. f F is the torque synthesis matrix of rotor lift. z Here is the rotor lift matrix, d1 and d2 are the lateral and longitudinal distances from the motor rotor to the center of mass of the fuselage, and f1 to f4 are the torques exerted by each rotor on the fuselage.

[0030] Step S1-4: Invert the transformation matrix:

[0031]

[0032] Step S1-5: Based on the impact conditions of the aircraft, obtain the vertical impact compensation:

[0033]

[0034] in: This is the actual vertical force matrix of the wheel hub. to These are the vertical compensation forces required for each wheel hub.

[0035] The required vertical compensation force for each wheel hub is:

[0036]

[0037] Where: K wp K wi K wd This is the vertical force compensation coefficient.

[0038] The process of determining the pose oscillation compensation includes:

[0039] Step S2-1: Obtain the attitude control matrix:

[0040]

[0041] in: T represents the angular acceleration of the body along the x, y, and z axes. att Let F be the attitude control matrix. z J is the rotor lift matrix. 3×3 Let T be the rotational inertia matrix. τ For the torque matrix, J xx J yy J zz Let C be the moment of inertia of the machine body about the x, y, and z axes. M C is the torque coefficient. L The lift coefficient;

[0042] Step S2-2: Invert the attitude control matrix:

[0043]

[0044] Step S2-3: Based on the body oscillation, obtain the vertical impact compensation:

[0045]

[0046] in: These are the high-frequency components of the body's x, y, and z axis angular accelerations, respectively.

[0047] The high-frequency components of the body's x, y, and z-axis angular accelerations satisfy the following:

[0048]

[0049] Wherein: F HP It is a high-pass filter.

[0050] The process of determining the lateral motion compensation includes:

[0051] Step S3-1: Determine the lateral displacement constraints for the flying car's land-to-air transition:

[0052]

[0053] in: T is the lateral acceleration of the body. ylim Here, H is the lateral motion compensation matrix, H is the lateral displacement coefficient matrix, and T is... m is the lateral motion transformation matrix of rotor lift, and m is the total mass of the flying car;

[0054] Step S3-2: Determine lateral motion compensation:

[0055]

[0056] A cross-domain motion control device for an electric-driven flying car includes a memory, a processor, and a program stored in the memory, characterized in that the processor executes the program to implement the method described above.

[0057] Compared with the prior art, the present invention has the following beneficial effects: it can realize the smooth transition of flying cars from flight state to ground state by relying on nearly four rotors, reduce the high-frequency vibration of the body and the peak vertical force on a single wheel hub, increase transition stability, reduce wheel hub wear, and increase suspension life, thus meeting the stability requirements and body safety requirements under passenger conditions. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the electric drive system for the electric-driven flying car of the present invention;

[0059] Figure 2 This is a schematic diagram of the lateral displacement constraint and impact compensation scheme for the electric-driven flying car of the present invention;

[0060] Figure 3 This is a schematic diagram of the main steps of the method of the present invention. Detailed Implementation

[0061] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0062] This application analyzes, for example... Figure 1 Based on the shown motion and dynamic characteristics of the electric drive system, dynamic models and variable parameter linear models of various modes of the electric drive flying car are established. Based on these models, such as... Figure 2 As shown, a real-time control distribution matrix is ​​established between control force, control torque, and actual control commands, based on the characteristics of each rotor and hub motor, to achieve real-time and rapid control input distribution. A land-air mode controller and compensation scheme are designed to achieve coordinated cross-domain motion control of the flying car. A switching process compensation scheme is determined based on road lateral limits, safety requirements, and driving comfort requirements. A vertical impact compensation control model for rotor active control is established based on hub feedback and safety requirements. A compensation control model for high-frequency oscillation components of the airframe is established based on driving comfort requirements. Lateral motion constraint control for the airframe during the near-ground phase is established based on road lateral limits.

[0063] First, the motion characteristics of the quadcopter flying car need to be analyzed, and a position dynamics model needs to be established:

[0064]

[0065] Where m is the total mass of the flying car, g is the gravitational acceleration, and f is the resultant force of the rotor lift and the hub ground model.

[0066] Furthermore, the motion characteristics of the quadcopter flying car are analyzed, and an attitude dynamics model is established as follows:

[0067]

[0068] Among them, J xx J yy J zz These are the moments of inertia about the x, y, and z axes of the body coordinate system, respectively. Let τ be the angular acceleration of the UAV along the x, y, and z axes, respectively. x , τ y , τ z This is the torque acting on the machine body axis.

[0069] Furthermore, the ground attitude of the quadcopter flying car is analyzed, and an attitude coordinate transformation model is established as follows:

[0070]

[0071] in, θ and ψ represent the roll angle, pitch angle, and yaw angle of the UAV, respectively.

[0072] Furthermore, considering ground mode, the lateral and longitudinal friction forces of the wheel hub are linked to the slip ratio. Since the wheel hub has no lateral driving force, there is no rolling motion or lateral displacement driven by the motor. The positional dynamics model in ground mode is as follows:

[0073]

[0074] Among them, f xi f yi f zi i = 1, 2, 3, 4 are the lateral, longitudinal, and vertical components of the ground support force on each wheel hub.

[0075] The attitude dynamics model is as follows:

[0076]

[0077] The attitude coordinate transformation model is as follows:

[0078]

[0079] Furthermore, considering the total thrust and torque provided by the rotor in a quadcopter configuration based on motor characteristics,

[0080]

[0081] Where d1 and d2 are the lateral and longitudinal distances from the motor rotor to the center of mass of the machine body, respectively, and C... L C is the lift coefficient. M ω is the torque coefficient. i i = 1, 2, 3, 4 are the angular velocities of each motor.

[0082] Furthermore, considering the attitude coupling under the multi-rotor premise, a four-rotor, four-wheel hub electric drive system layout is adopted. The linearized variable parameter model of the electric drive flying car is as follows:

[0083]

[0084] w P i =[f xi f yi f zi ] T g e =[0 0 9.8 0 0 0] T

[0085] in, f P represents the rotor lift output. This is the rotor force composition matrix. w P i The ground support force experienced by each wheel hub, The hub force synthesis matrix, For status output, Θ is the coordinate transformation matrix between the aircraft and the ground, and Θ is the attitude input.

[0086] Specifically, a cross-domain motion control method for an electrically driven flying car, such as... Figure 3 As shown, it includes:

[0087] When in flight and switching to transition mode, it receives sensor information and extracts the distance to the ground based on the acquired sensor information;

[0088] Determine whether the distance from the ground is less than a first set threshold. If it is, determine whether the distance from the ground is less than a second set threshold. If it is, generate a transition strategy compensation input based on pose oscillation compensation, vertical impact compensation, and lateral motion compensation. Otherwise, generate a transition strategy compensation input based on lateral motion compensation.

[0089] The power distribution output is obtained by compensating the input of the transition strategy and correcting the system control input, and then the operation of each rotor is controlled based on the obtained power distribution output.

[0090] Design a controller to implement pose-coupled flight mode control, denoted as:

[0091] x s(t)=x(t)+w(t)

[0092] Where x(t) is the actual motion path and w(t) is the measurement noise, a feedforward PID controller is established based on the sensor input, and the actual system control input u(t) is obtained as follows:

[0093] u(t) = K p x Δ (t)+K i ∫x Δ (t)dt+K d x Δ (t)

[0094] x Δ (t)=x s (t)-d r (t)

[0095] Furthermore, during the takeoff and landing of the flying car, the vertical impact from the ground on the wheel hub and the slippage caused by excessive speed difference can both lead to motion errors and strong vibrations in the airframe. To meet the safety and driving comfort requirements under passenger-carrying conditions, it is necessary to control the actual impact magnitude on the airframe. The airframe's shock absorption system alone is insufficient; therefore, the electric drive system control strategy needs to be compensated to constrain the real-time impact during motion within the required range. The power distribution output is as follows:

[0096] U d (t)=u(t)+ε(t)

[0097] Among them: U d ε(t) is the power distribution output, u(t) is the system control input, and ε(t) is the transient strategy compensation input.

[0098] The transition strategy compensation input is:

[0099] ε(t)=Mx s (t)+Nn(t)+Kk(t)

[0100] Where: M is the trajectory compensation matrix, x s (t) is the pose sensor input, N is the oscillation compensation matrix, n(t) is the high-frequency oscillation signal, K is the impact compensation matrix, and k(t) is the impact input.

[0101] The process of acquiring high-frequency oscillation signals includes:

[0102] The original oscillation signal is obtained based on the angular velocity;

[0103] The original oscillation signal is high-pass filtered to obtain a high-frequency oscillation signal.

[0104] The process of determining vertical impact compensation includes:

[0105] Step S1-1: Considering that the wheel hubs do not land at the same time and that the compression of the wheel hubs and the shock absorption system is uneven, the theoretical and actual vertical impacts of the ground on each wheel hub are recorded as follows:

[0106]

[0107] Where: N d N is the theoretical vertical impact matrix. s f is the actual vertical impact matrix. wzd1 to f wzd4 The theoretical vertical impacts, f, caused by each wheel hub on the ground are respectively. wzs1 to f wzs4 These represent the actual vertical impacts caused by each wheel hub on the ground;

[0108] Step S1-2: Determine the torque of a single wheel hub vertical impact on the machine body as follows:

[0109]

[0110] Wherein: T w F is the torque synthesis matrix of the vertical force at the hub. wz The vertical force matrix of the wheel hub is τ. wzx Let τ be the x-axis component of the torque of the vertical impact on the center of mass of the wheel hub. wzy D1 and D2 are the y-axis component of the torque of the vertical impact of the hub on the center of mass, and the lateral and longitudinal distances from the hub to the center of mass of the machine body, respectively.

[0111] Step S1-3: Determine the torque of the multirotor lift about the center of mass:

[0112]

[0113] Where: τ x Let τ be the x-axis component of the rotor lift torque about the center of mass. y T is the y-axis component of the rotor lift torque about the center of mass. f F is the torque synthesis matrix of rotor lift. z Here is the rotor lift matrix, d1 and d2 are the lateral and longitudinal distances from the motor rotor to the center of mass of the fuselage, and f1 to f4 are the torques exerted by each rotor on the fuselage.

[0114] Step S1-4: Invert the transformation matrix:

[0115]

[0116] Step S1-5: Based on the impact conditions of the aircraft, obtain the vertical impact compensation:

[0117]

[0118] in: This is the actual vertical force matrix of the wheel hub. to These are the vertical compensation forces required for each wheel hub.

[0119] The required vertical compensation force for each wheel hub is:

[0120]

[0121] Where: K wp K wi K wd This is the vertical force compensation coefficient.

[0122] The process of determining pose oscillation compensation includes:

[0123] Step S2-1: Obtain the attitude control matrix:

[0124]

[0125] in: T represents the angular acceleration of the body along the x, y, and z axes. att Let F be the attitude control matrix. z J is the rotor lift matrix. 3×3 Let T be the rotational inertia matrix. τ For the torque matrix, J xx J yy J zz Let C be the moment of inertia of the machine body about the x, y, and z axes. M C is the torque coefficient. L The lift coefficient;

[0126] Step S2-2: Invert the attitude control matrix:

[0127]

[0128] Step S2-3: Based on the body oscillation, obtain the vertical impact compensation:

[0129]

[0130] in: These are the high-frequency components of the body's x, y, and z axis angular accelerations, respectively.

[0131] The high-frequency components of the body's x, y, and z axis angular accelerations satisfy the following:

[0132]

[0133] Wherein: F HP It is a high-pass filter.

[0134] The process of determining lateral motion compensation includes:

[0135] Step S3-1: Determine the lateral displacement constraints for the flying car's land-to-air transition:

[0136]

[0137] in: T is the lateral acceleration of the body. ylim Here, H is the lateral motion compensation matrix, H is the lateral displacement coefficient matrix, and T is... m is the lateral motion transformation matrix of rotor lift, and m is the total mass of the flying car;

[0138] Step S3-2: Determine lateral motion compensation:

[0139]

[0140] Furthermore, when the robot is in ground mode, the rotor mechanism in flight mode stops operating, and the tilt angle is fixed at 0. The z-axis and attitude angle are constrained by the ground, satisfying:

[0141] z c +R zi p i =z s >z wheel +x min ≥z wkeel ≥z ground +r w >z ground

[0142] Among them, z s For the height of each suspension mounting point, z wheel For hub axle height, x min z represents the minimum compressed length or physical limit position of the suspension. ground r represents the ground position. w p is the natural radius of the wheel hub. i i = 1, 2, 3, 4 are the position vectors of the wheel hub relative to the center of mass, R zi , i = 1, 2, 3, 4 are the rotation matrices for each hub height.

[0143] During the air-to-land transition, the transition operation is divided into the following steps: First, maintain a constant speed in flight mode, constraining the attitude angle to meet the safety threshold; the pilot switches gears to enter transition mode and inputs the expected coordinates for the road mode; the system plans the air-to-land path and transition scheme based on the target; the system enters transition mode, and the aircraft slowly decreases its flight altitude to the near-ground altitude threshold; the land mode electric drive system is activated, the hub motors are enabled, and the flight mode electric drive system remains enabled, matching the hub motor speed and constraining the tire bottom speed and the theoretical slip ratio of the ground; the aircraft moves near the ground along the direction of road traffic, while the rotors slowly decrease the aircraft's flight altitude and constrain lateral movement deviation, allowing the vehicle to enter the traffic flow or land on the runway; upon reaching the predetermined ground contact altitude, rotor impact compensation is activated to constrain the aircraft's turbulence and impact magnitude; the aircraft slowly decreases to the aircraft's ground mode equilibrium altitude, the rotors slowly stop, and the tilt angle is adjusted to 0; after the aircraft is generally stable, the rotor electric drive system is shut down, and the aircraft enters land mode.

[0144] Finally, based on basic safety requirements, the vertical impact safety threshold f of the wheel hub is designed. lim Anti-rollover angle safety threshold Safety threshold ω for body oscillation angular velocity lim With angular acceleration safety threshold α lim When the safety threshold is exceeded, it may lead to damage to the aircraft and flight safety issues. Based on 80% of the safety threshold, a comparative scheme for hub impact, path deviation and aircraft vibration is designed according to sensor signals. The scheme is compared with the system safety index. If it is within the safety index, the flying car control effect is good. Otherwise, if the evaluation function value exceeds the threshold, it is determined that the system's land-to-air transition is not smooth or there may be safety hazards. Then, the impact curves and over-threshold situations of each channel are analyzed, the compensation scheme and compensation coefficient are modified, and the control scheme is continuously optimized.

[0145] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A cross-domain motion control method for an electrically driven flying car, characterized in that, include: When in flight and switching to transition mode, it receives sensor information and extracts the distance to the ground based on the acquired sensor information; Determine whether the distance from the ground is less than a first set threshold. If it is, determine whether the distance from the ground is less than a second set threshold. If it is, generate a transition strategy compensation input based on pose oscillation compensation, vertical impact compensation, and lateral motion compensation. Otherwise, generate a transition strategy compensation input based on lateral motion compensation. The power distribution output is obtained by correcting the system control input according to the transition strategy compensation input, and the operation of each rotor is controlled based on the obtained power distribution output; The power distribution output is: in: To distribute power output, For system control input, To compensate for the input in the transition strategy; The transition strategy compensation input is: in: M For the trajectory compensation matrix, Input for the pose sensor, N For the oscillation compensation matrix, It is a high-frequency oscillation signal. K For the impact compensation matrix, For impact input; The process of determining the vertical impact compensation includes: Step S1-1: Considering that the wheel hubs do not land at the same time and that the compression of the wheel hubs and the shock absorption system is uneven, the theoretical and actual vertical impacts of the ground on each wheel hub are recorded as follows: in: N d This is the theoretical vertical impact matrix. N s This is the actual vertical impact matrix. to These represent the theoretical vertical impacts caused by each wheel hub on the ground. to These represent the actual vertical impacts caused by each wheel hub on the ground; Step S1-2: Determine the torque of a single wheel hub vertical impact on the machine body as follows: in: This is the torque synthesis matrix of the vertical force at the wheel hub. The hub vertical force matrix, For the vertical impact of the wheel hub on the center of gravity torque x Axial component, For the vertical impact of the wheel hub on the center of gravity torque y Axial component, , The lateral and longitudinal distances from the wheel hub to the center of gravity of the fuselage; Step S1-3: Determine the torque of the multirotor lift about the center of mass: in: Let x be the x-axis component of the rotor lift torque about the center of mass. Let be the y-axis component of the rotor lift torque about the center of mass. This is the torque synthesis matrix for rotor lift. For the rotor lift matrix, , The lateral and longitudinal distances from the motor rotor to the center of mass of the machine body are denoted as . to These are the torques exerted by each rotor on the fuselage; Step S1-4: Invert the transformation matrix: Step S1-5: Based on the impact conditions of the aircraft, obtain the vertical impact compensation: in: This is the actual vertical force matrix of the wheel hub. to These are the vertical compensation forces required for each wheel hub.

2. The cross-domain motion control method for an electrically driven flying car according to claim 1, characterized in that, The process of acquiring the high-frequency oscillation signal includes: The original oscillation signal is obtained based on the angular velocity; The original oscillation signal is high-pass filtered to obtain a high-frequency oscillation signal.

3. The cross-domain motion control method for an electrically driven flying car according to claim 1, characterized in that, The required vertical compensation force for each wheel hub is: in: , , This is the vertical force compensation coefficient.

4. The cross-domain motion control method for an electrically driven flying car according to claim 1, characterized in that, The process of determining the pose oscillation compensation includes: Step S2-1: Obtain the attitude control matrix: in: , , The angular accelerations of the body along the x, y, and z axes are... This is the attitude control matrix. For the rotor lift matrix, Here is the rotational inertia matrix. For torque matrix, , , Let x be the moment of inertia of the machine body about the x, y, and z axes. The torque coefficient, The lift coefficient; Step S2-2: Invert the attitude control matrix: Step S2-3: Based on the body oscillation, obtain the vertical impact compensation: in: , , These are the high-frequency components of the body's x, y, and z axis angular accelerations, respectively.

5. The cross-domain motion control method for an electrically driven flying car according to claim 4, characterized in that, The high-frequency components of the body's x, y, and z-axis angular accelerations satisfy the following: in: It is a high-pass filter.

6. The cross-domain motion control method for an electrically driven flying car according to claim 4, characterized in that, The process of determining the lateral motion compensation includes: Step S3-1: Determine the lateral displacement constraints for the flying car's land-to-air transition: in: For the lateral acceleration of the body, This is the lateral motion compensation matrix. This is the matrix of lateral displacement coefficients. This is the transformation matrix for the lateral motion of rotor lift. The total mass of the flying car; Step S3-2: Determine lateral motion compensation: 。 7. A cross-domain motion control device for an electrically driven flying car, comprising a memory, a processor, and a program stored in the memory, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1-6.

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