CN112818463A

CN112818463A - Multimode air-ground amphibious vehicle platform simulation system

Info

Publication number: CN112818463A
Application number: CN202110081611.3A
Authority: CN
Inventors: 张新钰; 谭启凡; 李骏; 刘华平; 孙弘麟; 殷越; 周沫
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2021-01-21
Filing date: 2021-01-21
Publication date: 2021-05-18
Anticipated expiration: 2041-01-21
Also published as: CN112818463B

Abstract

The invention discloses a multi-mode air-ground amphibious vehicle platform simulation system, relates to the technical field of air-ground amphibious vehicles, and aims to solve the problem that none of the simulation systems in the prior art can simulate the flight process of the air-ground amphibious vehicle and simulate the road driving process. The multi-mode air-ground amphibious vehicle platform simulation system comprises: a simulation platform and a motion controller in communication with the simulation platform. The simulation platform comprises a simulation environment and an air-ground amphibious vehicle positioned in the simulation environment. The description model of the air-ground amphibious vehicle comprises a flight dynamic model and a vehicle dynamic model which are coupled. The motion controller is used for sending a control command to the simulation platform according to the motion command, and the simulation platform is used for controlling the air-ground amphibious vehicle to operate in the simulation environment according to the control command. The motion controller is also used for collecting perception information of the simulation platform and updating the control instruction according to the perception information. The perception information comprises the state of the simulation environment and the state of the air-ground amphibious vehicle.

Description

Multimode air-ground amphibious vehicle platform simulation system

Technical Field

The invention relates to the technical field of air-ground amphibious vehicles, in particular to a multi-mode air-ground amphibious vehicle platform simulation system.

Background

An air-ground amphibious vehicle is a mobile platform which can run on the road surface and can fly in the air. The air-ground amphibious characteristic endows the unmanned aerial vehicle with excellent maneuvering capability compared with a common ground vehicle and longer cruising capability compared with an unmanned aerial vehicle. However, in the practical application process, the air-ground amphibious vehicle is limited by high development cost, flight control and the like, so that the technology is slowly developed.

The simulation system can simulate the motion process of the air-ground amphibious vehicle, but none of the simulation systems in the prior art can simulate the flight process of the air-ground amphibious vehicle and simulate the road driving process.

Disclosure of Invention

The invention aims to provide a multi-mode air-ground amphibious vehicle platform simulation system which is used for realizing flight simulation and road surface driving simulation of an air-ground amphibious vehicle.

In order to achieve the above object, the present invention provides a multi-modal air-ground amphibious vehicle platform simulation system, comprising: a simulation platform and a motion controller in communication with the simulation platform. The simulation platform comprises a simulation environment and an air-ground amphibious vehicle positioned in the simulation environment. The description model of the air-ground amphibious vehicle comprises a flight dynamic model and a vehicle dynamic model which are coupled. The motion controller is used for sending a control command to the simulation platform according to the motion command, and the simulation platform is used for controlling the air-ground amphibious vehicle to operate in the simulation environment according to the control command. The motion controller is also used for collecting perception information of the simulation platform and updating the control instruction according to the perception information. The perception information comprises the state of the simulation environment and the state of the air-ground amphibious vehicle.

Compared with the prior art, the multi-mode air-ground amphibious vehicle platform simulation system provided by the invention comprises a simulation platform and a motion controller communicated with the simulation platform, wherein the simulation platform comprises a simulation environment and an air-ground amphibious vehicle positioned in the simulation environment. In practical application, the motion controller can receive motion instructions transmitted from the outside, and sends control instructions to the simulation platform according to the motion instructions, so that the simulation platform controls the air-ground amphibious vehicle to operate in a simulation environment according to the control instructions. And the motion controller can also acquire the perception information of the simulation platform, and can update the control instruction according to the perception information, so that the simulation running process of the air-ground amphibious vehicle in the simulation environment is continuously changed. At the moment, the user can observe the simulation process of the air-ground amphibious vehicle in the simulation environment at multiple angles, so that the problem of the air-ground amphibious vehicle in the simulation process is improved in the later period, namely, the multi-mode air-ground amphibious vehicle platform simulation system is beneficial to further research and development and improvement of the real air-ground amphibious vehicle, and meanwhile, the multi-mode air-ground amphibious vehicle platform simulation system can also avoid the cost problem and the flight control problem caused by movement of the real air-ground amphibious vehicle.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic structural diagram of a multi-modal air-ground amphibious vehicle platform simulation system provided by an embodiment of the invention;

FIG. 2 is a schematic structural diagram of a software-in-the-loop simulation system according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a hardware-in-the-loop simulation system according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of another multi-modal air-ground amphibious vehicle platform simulation system provided by the embodiment of the invention;

FIG. 5 is a schematic structural diagram of an air-ground amphibious vehicle provided by an embodiment of the invention;

FIG. 6 is a schematic structural diagram illustrating four motion states of an air-ground amphibious vehicle provided by the embodiment of the invention;

FIG. 7 is a schematic diagram illustrating the coupling between models provided by the embodiment of the present invention;

FIG. 8 is a schematic force diagram of a rotor wing part of an air-ground amphibious vehicle provided by an embodiment of the invention;

FIG. 9 is a schematic view illustrating state updating of a rotor portion of an air-ground amphibious vehicle provided by an embodiment of the invention;

FIG. 10 is a schematic diagram illustrating state updating of a wheel portion of an air-ground amphibious vehicle provided by an embodiment of the invention;

FIG. 11 shows a body stress analysis diagram of an air-ground amphibious vehicle provided by an embodiment of the invention;

FIG. 12 shows a stress analysis diagram of a whole vehicle 7-degree-of-freedom suspension model of an air-ground amphibious vehicle provided by the embodiment of the invention;

fig. 13 shows a schematic view of state updating of a body and a rotor bracket part of an air-ground amphibious vehicle provided by the embodiment of the invention.

Reference numerals:

the system comprises a computer 1, a simulation platform 2, a simulation environment 20, an air-ground amphibious vehicle 21, a motion control plug-in 22, a pose acquisition sensor 23, an environment perception sensor 24, a motion controller 3, a perception module 30, a pose acquisition sensor topic 300, an environment perception sensor topic 301, a control module 31, a flight control node 310, a chassis control node 311, a flight controller 32, a chassis controller 33, a motion instruction 4, a control instruction 5, perception information 6, a software-in-the-loop simulation system 7, a hardware-in-the-loop simulation system 8, a simulation interface 9, a simulation interface plug-in 10, a hardware interface 11, a flight vehicle 12, a vehicle 120, a suspension 1201, a wheel 1202 and a rotor wing 121; 13 is a rotor wing dynamic model, 14 is a vehicle dynamic model, 15 is a real air-ground amphibious vehicle, 150 is a pose collector, 151 is an environment sensor, 152 is a flight execution system, and 153 is a chassis execution system.

Detailed Description

In order to facilitate clear description of technical solutions of the embodiments of the present invention, in the embodiments of the present invention, terms such as "first" and "second" are used to distinguish the same items or similar items having substantially the same functions and actions. For example, the first threshold and the second threshold are only used for distinguishing different thresholds, and the sequence order of the thresholds is not limited. Those skilled in the art will appreciate that the terms "first," "second," etc. do not denote any order or quantity, nor do the terms "first," "second," etc. denote any order or importance.

It is to be understood that the terms "exemplary" or "such as" are used herein to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g.," is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.

In the present invention, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, a and b combination, a and c combination, b and c combination, or a, b and c combination, wherein a, b and c can be single or multiple.

Before describing the embodiments of the present invention, the related terms related to the embodiments of the present invention are first explained as follows:

hardware-in-the-loop simulation: the real-time processor operates the simulation model to simulate the operation state of the controlled object and is connected with the measured object through the I/O interface.

A double-track model: the model is a model for analyzing the unbalanced stress between the left wheel and the right wheel of the vehicle, the rolling of the suspension and the like by considering the width of the vehicle for the four-wheel vehicle.

Magic formula: fitting the tire test data by using a combined formula of trigonometric functions, and completely expressing the longitudinal force, the lateral force, the aligning moment, the overturning moment, the resisting moment of the tire and the combined action condition of the longitudinal force and the lateral force by using a set of formulas with the same form, so that the formula is called as a magic formula.

Gazebo: the robot simulator is a 3D dynamic simulator, and can accurately and effectively simulate robot groups in complex indoor and outdoor environments. Gazebo provides high fidelity physical simulation, similar to the game engine providing high fidelity visual simulation, and a large number of developers contribute rich model and plug-in resources, a very user-friendly way of interaction for users and programs.

ROS Control: the ROS Control is a middleware between an application provided by the ROS (Robot Operating System) for a user and a Robot, and includes a series of controller interfaces, transmission interfaces, hardware interfaces, controller toolboxes, and the like, which can help the Robot application to quickly land and improve development efficiency.

Octomap: a three-dimensional map creation tool based on octree can display complete 3D graphics including barrier-free areas and unmapped areas, and sensor data based on occupancy grids can be fused and updated in multiple measurements; the map can provide various resolutions, and the data is compressible and the storage is compact.

An air-ground amphibious vehicle is a mobile platform which can run on the road surface and can fly in the air. The air-ground amphibious characteristic endows the unmanned aerial vehicle with excellent maneuvering capability compared with a common ground vehicle and longer cruising capability compared with an unmanned aerial vehicle. However, in the practical application process, the air-ground amphibious vehicle is limited by high development cost, flight control and the like, so that the technology is slowly developed. The simulation system can simulate the motion process of the air-ground amphibious vehicle, but none of the simulation systems in the prior art can simulate the flight process of the air-ground amphibious vehicle and simulate the road driving process.

In order to solve the technical problem, the embodiment of the invention provides a multi-mode air-ground amphibious vehicle platform simulation system. Referring to fig. 1, the multi-modal air-ground amphibious vehicle platform simulation system comprises: a simulation platform 2 and a motion controller 3 in communication with the simulation platform 2. The simulation platform 2 comprises a simulation environment 20 and an air-ground amphibious vehicle 21 located within the simulation environment 20. The description model of the air-ground amphibious vehicle 21 comprises a coupled flight dynamics model and a vehicle dynamics model. The motion controller 3 is used for sending a control command 5 to the simulation platform 2 according to the motion command 4, and the simulation platform 2 is used for controlling the air-ground amphibious vehicle 21 to operate in the simulation environment 20 according to the control command 5. The motion controller 3 is further configured to collect perception information 6 of the simulation platform 2, and update the control instruction 5 according to the perception information 6. The perception information 6 includes the state of the simulation environment and the state of the air-ground amphibious vehicle.

The state of the simulation environment may include wind speed, pressure, road environment (e.g., road slope, presence or absence of obstacles), airborne environment (e.g., light, cloud), and the like. The state of the air-ground amphibious vehicle may include information such as a position of the air-ground amphibious vehicle, a posture of the air-ground amphibious vehicle, and the like. The simulation platform may be a Gazebo.

Referring to fig. 1, the multi-modal air-ground amphibious vehicle platform simulation system provided by the embodiment of the invention comprises a simulation platform 2 and a motion controller 3 communicated with the simulation platform 2, wherein the simulation platform 2 comprises a simulation environment 20 and an air-ground amphibious vehicle 21 located in the simulation environment 20. In practical application, the motion controller 3 may receive a motion instruction 4 transmitted from the outside, and send a control instruction 5 to the simulation platform 2 according to the motion instruction 4, so that the simulation platform 2 controls the air-ground amphibious vehicle 21 to operate in the simulation environment 20 according to the control instruction 5. Moreover, the motion controller 3 may further collect the perception information 6 of the simulation platform 2, and update the control command 5 according to the perception information 6, so that the simulation operation process of the air-ground amphibious vehicle 21 in the simulation environment 20 is changed continuously. At this moment, the user can observe the simulation process of the air-ground amphibious vehicle 21 in the simulation environment 20 from multiple angles, so that the problem of the air-ground amphibious vehicle 21 in the simulation process is improved in the later period, namely, the multi-mode air-ground amphibious vehicle platform simulation system is beneficial to further research and development and improvement of a real air-ground amphibious vehicle, and meanwhile, the multi-mode air-ground amphibious vehicle platform simulation system can also avoid the cost problem and the flight control problem caused by movement of the real air-ground amphibious vehicle.

As a possible implementation, referring to fig. 2, the motion controller 3 and the simulation platform 2 form a software-in-loop simulation system 7.

Illustratively, referring to fig. 2, the motion controller 3 is located in the same computer 1 as the simulation platform 2. At this time, the motion command 4 is input from the outside to the motion controller 3, and then the motion controller 3 generates a control command 5 according to the motion command 4 and sends the control command 5 to the simulation platform 2. And the air-ground amphibious vehicle in the simulation environment of the simulation platform 2 operates according to the control command 5, namely, simulation is carried out. The motion controller 3 is further configured to collect perception information 6 of the simulation platform 2, and update the control instruction 5 according to the perception information 6. It should be understood that the above-described motion controller 3 is a virtual motion controller provided in the computer 1. Through software-in-loop simulation, the motion command 4 or the control command 5 can be implemented in software, and the participation of hardware (such as a real air-ground amphibious vehicle and the like) is avoided. At the moment, the external interference is less, the damage to the real object and hardware can be reduced or avoided, the research and development progress of a user is improved, and meanwhile, the cost can be saved. Software the motion controller in the loop simulation system 7 may be an ROS system.

As another possible implementation, referring to fig. 3, the motion controller 3 and the simulation platform 2 form a hardware-in-loop simulation system 8.

Illustratively, referring to fig. 3, only the simulation platform 2 is located within the computer 1, and the motion controller 3 is separate from the simulation platform 2. For example, the motion controller 3 may be a controller originated from a real air-ground amphibious vehicle, and the motion controller 3 is mainly used for controlling the air-ground amphibious vehicle located in the simulation environment to fly or run on the road. The motion controller 3 may now include a flight controller 32 and a chassis controller 33. Further, the motion controller 3 may communicate with the simulation platform 2 through a hardware interface. The device running the simulation platform 2 can transmit the perception information 6 to the motion controller 3 through a TCP/UDP protocol, and the motion controller 3 can update the control command 5 according to the perception information 6, so that the simulation platform 2 can also receive the control command 5 transmitted back by the motion controller 3 to realize hardware-in-loop simulation. Through hardware-in-the-loop simulation, inherent attributes (possibly influencing the nature of a simulation result) of the motion controller 3 can be taken into account, so that the method is more real and accurate, is closer to the actual situation, and is more beneficial to research and development and improvement of a real air-ground amphibious vehicle by a user.

As a possible implementation manner, the simulation system of the air-ground amphibious vehicle is a visual simulation system.

The simulation of the motion process of the air-ground amphibious vehicle is mainly used for researching whether a real air-ground amphibious vehicle has a problem in the motion process and a place where the real air-ground amphibious vehicle has the problem, so that the structure or the control process of the actual air-ground amphibious vehicle can be modified and perfected in the later period. Therefore, when the air-ground amphibious vehicle in the simulation platform is simulated, the motion process of the air-ground amphibious vehicle in different states needs to be observed in real time, and the problems of the air-ground amphibious vehicle in the motion process need to be recorded. Based on this, the simulation system of the air-ground amphibious vehicle provided by the embodiment of the invention needs to be a visual simulation system. For example, the simulation platform may be a visualized Gazebo.

As a possible implementation, the motion controller includes: and the sensing module is communicated with the air-ground amphibious vehicle and is used for acquiring sensing information of the simulation platform. And the control module is communicated with the sensing module and the air-ground amphibious vehicle and is used for controlling the air-ground amphibious vehicle to operate in the simulation environment according to the motion instruction. And controlling the air-ground amphibious vehicle to run in the simulation environment according to the perception information.

For example, referring to fig. 1 and 4, the motion controller 3 has a perception module 30 because the motion controller 3 can collect perception information 6 of the simulation platform 2. For example, since the sensing information 6 may be acquired by a virtual sensor in the simulation platform 2, the motion controller 3 may set a sensor topic corresponding to the virtual sensor in the sensing module 30 to subscribe to the virtual sensor sensing data from the simulation interface 9 in order to acquire the sensing information 6. The virtual sensor can sense and simulate external environment information. The virtual sensors may include a pose acquisition sensor 23 and an environment perception sensor 24 (specifically, the virtual sensors that may be generated in the simulation platform 2 include a vision camera, a laser radar, a GPS, and the like). The sensor topics described above may be a pose collection sensor topic 300 and an environment perception sensor topic 301.

Further, referring to fig. 1 and 4, the motion controller 3 further includes a control module 31. The motion controller 3 can receive the motion command 4 input from the outside and send the control command 5 to the simulation platform 2 according to the motion command 4, and then the simulation platform 2 can control the air-ground amphibious vehicle 21 to operate in the simulation environment 20 according to the control command 5. That is, the control module 31 in the motion controller 3 may indirectly control the operation of the air-ground amphibious vehicle 21 in the simulation environment 20 according to the motion command 4. At this time, a flight control node 310 and a chassis control node 311 are correspondingly arranged in the control module 31, wherein the flight control node 310 is mainly used for controlling the flight of the air-ground amphibious vehicle 21, and the chassis control node 311 is mainly used for controlling the air-ground amphibious vehicle 21 to run on the road surface.

Referring to fig. 1 and 4, since the perception information 6 in the simulation platform 2 changes continuously due to the movement of the air-ground amphibious vehicle 21, the control command 5 generated in the motion controller 3 changes correspondingly. For example, since the perception information 6 includes the state of the simulation environment 20 and the state of the air-ground amphibious vehicle 21. When the air-ground amphibious vehicle 21 changes from the takeoff state to the flight state, the position and the distance of the air-ground amphibious vehicle 21 relative to the ground are changed. During the flight, the attitude of the air-ground amphibious vehicle 21 may also change, and the state of the simulation environment 20 around the corresponding air-ground amphibious vehicle 21 may also change (e.g., wind speed, pressure, etc.). Since the change of the perception information 6 can cause the control command 5 generated in the motion controller 3 to correspondingly change, at this time, the control module 31 needs to control the air-ground amphibious vehicle 21 to operate in the simulation environment 20 according to the updated control command 5, that is, the control module 31 controls the air-ground amphibious vehicle 21 to operate in the simulation environment 20 according to the perception information 6.

Referring to fig. 1 and 4, a motion control plug-in 22 corresponding to the motion controller 3 is further disposed in the simulation platform 2, and the motion control plug-in 22 is connected to the simulation interface plug-in 10 disposed in the simulation platform 2. The flight control node 310 and the chassis control node 311 in the motion controller 3 are connected with the simulation interface 9, and the simulation interface 9 is connected with the simulation interface plug-in 10. At this time, the information is transmitted to the motion control plug-in 22 through the simulation interface plug-in 10 to control the air-ground amphibious vehicle 21 (i.e. the three-dimensional model of the real air-ground amphibious vehicle) located in the simulation environment 20 to perform simulation. Further, the pose collection sensor 23 and the environment sensing sensor 24 are also connected to the simulation interface plug-in 10, the pose collection sensor topic 300 and the environment sensing sensor topic 301 are connected to the simulation interface 9, and the simulation interface 9 is connected to the simulation interface plug-in 10. At this time, the pose collection sensor 23 and the environment sensing sensor 24 can transmit information to the pose collection sensor topic 300 and the environment sensing sensor topic 301 through the simulation interface plug-in 10 and the simulation interface 9. Further, the pose collection sensor topic 300 and the environment perception sensor topic 301 respectively perform data transmission with the flight control node 310 and the chassis control node 311, and at this time, a closed-loop structure may be formed. The pose and environment information collected by the pose collection sensor topic 300 and the environment perception sensor topic 301 are transmitted to the flight control node 310 and the chassis control node 311 for adjusting the control output.

Referring to fig. 3 and 4, when the motion controller 3 and the simulation platform 2 form the hardware-in-the-loop simulation system 8, the pose collection sensor 23 and the environment sensing sensor 24 transmit information to the pose collection sensor topic 300 and the environment sensing sensor topic 301 through the simulation interface plug-in 10 and the simulation interface 9. Then, the information is transmitted to the flight controller 32 and the chassis controller 33 through the hardware interface 11, that is, the transmission process of "perception information 6" in fig. 3 can be embodied. After that, the flight controller 32 and the chassis controller 33 are again transferred to the motion control plug-in 22 through the hardware interface 11, the emulation interface 9, and the emulation interface plug-in 10, and the control instructions 5 returned by the flight controller 32 and the chassis controller 33 are executed in the emulation platform 2.

Referring to fig. 3 and 4, the pose collector 150 and the environment sensor 151 are various sensors for collecting the pose of the real air-ground amphibious vehicle 15 and the surrounding environment information, and transmitting the information to the flight controller 32 and the chassis controller 33, so that a closed-loop structure may be formed. Flight controller 32 then transmits the information to flight execution system 152, and chassis controller 33 transmits the information to chassis execution system 153. The flight controller 32 and the chassis controller 33 convert the motion commands 4 into the control commands 5 by calculation. For example, chassis forward speed may be converted to chassis motor voltage/duty cycle. The flight execution system 152 and the chassis execution system 153 are used to execute the control instructions 5 transmitted from the flight controller 32 and the chassis controller 33. The motion controller 3 in fig. 4 may be a robot operating system ROS.

As a possible implementation, the control commands may include wheel control information and rotor control information.

For example, a part of models in the vehicle dynamic model can be controlled by using wheel control information, the flight dynamic model can be controlled by using rotor control information, and the wheel control information and the rotor control information can be used as control instructions to control the air-ground amphibious vehicle to move in four states of takeoff, flight, landing and road surface driving due to the mutual coupling of the flight dynamic model and the vehicle dynamic model.

In one example, the wheel control information may include tire steering information and tire mechanics information. The tire steering information may include, among other things, a steering angle, which is the angle by which each tire rotates about the z-axis. The tire mechanics information may include tire drive torque and tire braking torque. The rotor control information may include rotor motor torque. Of course, the information included in the wheel control information and the rotor control information may be set according to actual needs, and is not limited to the above information.

As a possible implementation, referring to fig. 5, the above-mentioned air-ground amphibious vehicle may be a flying vehicle 12, the flying vehicle 12 may include a vehicle 120 and a rotor 121 provided on the vehicle 120, and the vehicle 120 may include a suspension 1201 and wheels 1202 provided on the suspension 1201.

Illustratively, referring to fig. 5, the vehicle 120 mainly provides the flying vehicle 12 with driving force for traveling on a road surface, so that the flying vehicle 12 can travel on the road surface. It should be understood that the vehicle 120 may be a four-wheel vehicle, a six-wheel vehicle, a two-wheel motorcycle, etc., as long as it has road surface traveling capability, and the specific structure of the vehicle 120 is not particularly limited in the embodiment of the present invention. The vehicle 120 may be an unmanned vehicle or a manned vehicle. The vehicle may be an automobile, other vehicle or device in the form of other vehicles such as cars, trucks, motorcycles, buses, etc.

Referring to fig. 5, the rotor 121 primarily provides a flight driving force for the flying vehicle 12 to enable the flying vehicle 12 to fly in the air. It should be understood that the rotor may be a six-rotor, a four-rotor, etc., or may be other rotors having flight functions. The rotor is a rigid body, and the rotor 121 is rigidly connected to the vehicle 120.

Referring to fig. 6, the air-ground amphibious vehicle has four motion states of take-off, flight, landing and road surface driving in the actual motion process, and especially, a plurality of transient processes which are difficult to analyze are often accompanied during take-off and landing, so that a user needs to find a reasonable model to describe the dynamic characteristics of the air-ground amphibious vehicle in different motion states. For example, in the takeoff situation, both the rotor and the vehicle (i.e. the rotor dynamics model 13 and the vehicle dynamics model 14) will be involved. The vehicle and the rotor wing provide power for the air-ground amphibious vehicle and jointly control the air-ground amphibious vehicle to move. In flight conditions, the rotor is mainly involved (i.e. the rotor dynamics model 13 is involved). The rotor provides power for the air-ground amphibious vehicle and controls the air-ground amphibious vehicle to move. In the landing situation, both the rotor and the vehicle (i.e. the rotor dynamics model 13 and the vehicle dynamics model 14) will be involved. The vehicle and the rotor wing provide power for the air-ground amphibious vehicle and jointly control the air-ground amphibious vehicle to move. In the road running state, the vehicle is mainly involved (i.e., the vehicle dynamics model 14 is involved). The vehicle provides power for the air-ground amphibious vehicle and controls the air-ground amphibious vehicle to move. When the vehicle and the rotor wing jointly provide power for the air-ground amphibious vehicle, the vehicle and the rotor wing can influence each other, and the motion process of the air-ground amphibious vehicle is complex at the moment. In order to better develop and improve the air-ground amphibious vehicle, the air-ground amphibious vehicle in the landing state is selected for analysis in the embodiment of the invention.

As a possible implementation manner, referring to fig. 7, the flight dynamics model is a rotor dynamics model, the vehicle dynamics model includes a wheel model and a body and rotor support model, and the body and rotor support model are respectively coupled with the wheel model and the rotor dynamics model.

Illustratively, the wheel control information and other information (e.g., road surface excitation) is input to the wheel model to obtain the output information of the wheel model, see fig. 7. The output information of the wheel model is then transmitted to the body and rotor pylon model, i.e. as a first input of the body and rotor pylon model. And inputting the rotor wing control information into the rotor wing dynamic model to obtain the output information of the rotor wing dynamic model. The output information of the rotor dynamics model is then also transmitted to the body and rotor support model, i.e. as a second input for the body and rotor support model. And simultaneously inputting the first input and the second input of the automobile body and the rotor wing bracket model into the automobile body and the rotor wing bracket model to obtain the output information of the automobile body and the rotor wing bracket model. And then the output information of the vehicle body and the rotor wing bracket model is fed back to the wheel model and the rotor wing dynamic model. According to the above content, the vehicle body and the rotor wing bracket model are respectively coupled with the wheel model and the rotor wing dynamic model, and jointly act on the air-ground amphibious vehicle and influence the movement of the air-ground amphibious vehicle.

In one example, referring to fig. 7, the input information of the wheel model may include tire steering information, mechanical information of the tire, and output information of the body and rotor support model. The output information of the wheel model may include suspension spring force, suspension damping force, tire longitudinal force, and tire lateral force. The input information to the rotor dynamics model may include rotor motor torque and output information for the body and rotor pylon models. The output information of the rotor dynamics model may include rotor lift and moment, and rotor rotational speed. The input information for the body and rotor pylon models can include output information for the wheel models and output information for the rotor dynamics models.

For example, referring to fig. 7, it can be understood from the foregoing description that the tire steering information and the tire mechanics information belong to the wheel control information. The tire steering information may include, among other things, a steering angle. The tire mechanics information may include tire drive torque and tire braking torque. Rotor motor torque is a function of rotor control information. The output information of the body and rotor pylon models can include body attitude and center of gravity position.

In one example, an air-ground amphibious vehicle is subjected to parameter identification to determine relevant parameters. For example, the parameters may be vehicle mass, moment of inertia, rotor mass, aerodynamic parameters, stiffness and damping of tires and suspensions, etc. Next, the rotor section, the wheel section, the body section, and the rotor pylon section are analyzed and state updated using the rotor dynamics model, the wheel model, the body section, and the rotor pylon model, respectively.

For example, referring to fig. 8, when the rotor portion employs a six-rotor drone, six rotors of the six-rotor drone are arranged at the vertex position of a hexagon, and the pulling force of the six rotors is used as the operating force, so that the rotating directions of the six rotors can be designed to be different, and the posture and the position of the six-rotor drone can be changed by changing the rotating speed of the rotors. Define the host vehicle coordinate system b (O-xyz) (i.e., with O)_bCoordinate system as origin) is in the bilateral symmetry plane of the six-rotor drone, and the positive direction of the x-axis points to the head direction of the six-rotor drone. The z-axis is in the bilateral symmetry plane of the body, and the positive direction of the z-axis is pointed to the upper part of the six-rotor unmanned aerial vehicle by the center of the six-rotor unmanned aerial vehicle. The y-axis that is 90 degrees contained angle with the x-axis is perpendicular to the xz plane, and the positive direction of y-axis points to six rotor unmanned aerial vehicle's right side. As shown in fig. 8, 1, 3, 5 rotors rotate clockwise,the rotor blades are 'positive propellers', the 2, 4 and 6 rotor blades rotate anticlockwise, and the rotor blades are 'negative propellers'. Just because the differential matching of six rotor rotational speeds, the various flight action changes of six rotor unmanned aerial vehicle have just been realized.

Referring to fig. 8, the air-ground amphibious vehicle is simplified for ease of description and control. For example, the values of the vehicle mass, the moment of inertia, and the rotor mass are unchanged. Air resistance is proportional to linear velocity. Meanwhile, in order to facilitate unification of the respective coordinate systems, a global coordinate system n (O-XYZ) (i.e., in terms of O) is defined_NCoordinate system as origin) and the host vehicle coordinate system b (o-xyz), using a rotation matrixⁿT_bThe mutual conversion relation between the positions of the two coordinate systems can be obtained:

phi represents the rolling angle of the air-ground amphibious vehicle around the X axis in the global coordinate system, theta represents the pitching angle of the air-ground amphibious vehicle around the Y axis in the global coordinate system, and psi represents the yaw angle of the air-ground amphibious vehicle around the Z axis in the global coordinate system.

Using a rotation matrixⁿD_bThe rotational speed conversion relationship between two coordinate systems can be obtained:

similarly, phi represents the rolling angle of the air-ground amphibious vehicle around the X axis in the global coordinate system, theta represents the pitching angle of the air-ground amphibious vehicle around the Y axis in the global coordinate system, and psi represents the yaw angle of the air-ground amphibious vehicle around the Z axis in the global coordinate system.

According to Newton's law of motion, the rotor dynamics model can be known to satisfy the following equation set:

wherein, K₁Denotes the first aerodynamic damping parameter, K₂Representing a second aerodynamic damping parameter, K₃Represents a third aerodynamic damping parameter, K₄Denotes a fourth aerodynamic damping parameter, K₅Denotes a fifth aerodynamic damping parameter, K₆Represents a sixth aerodynamic damping parameter; m_rRepresenting the mass of a rotor wing in the air-ground amphibious vehicle, and g representing the gravity acceleration; v_XRepresenting the speed, V, of an air-ground amphibious vehicle in the X-axis direction in a global coordinate system_YRepresenting the speed, V, of the air-ground amphibious vehicle in the Y-axis direction in the global coordinate system_ZRepresenting the speed of the air-ground amphibious vehicle in the Z-axis direction in the global coordinate system;

represents the acceleration of the air-ground amphibious vehicle in the X-axis direction in the global coordinate system,

represents the acceleration of the air-ground amphibious vehicle in the Y-axis direction in the global coordinate system,

representing the acceleration of the air-ground amphibious vehicle in the Z-axis direction in a global coordinate system; phi represents the rolling angle of the air-ground amphibious vehicle around the X axis in the global coordinate system, theta represents the pitch angle of the air-ground amphibious vehicle around the Y axis in the global coordinate system, and psi represents the yaw angle of the air-ground amphibious vehicle around the Z axis in the global coordinate system; j. the design is a square_xRepresenting moment of inertia, J, about the x-axis of the vehicle relative to the center of mass_yRepresenting the moment of inertia, J, about the ground-air amphibious vehicle y-axis relative to the center of mass_zRepresenting the moment of inertia around the z-axis of the air-ground amphibious vehicle relative to the center of mass; l represents the radius of a rotor bracket of the air-ground amphibious vehicle; u shape₁Representing the power input of the land-air amphibious vehicle in the vertical motion in the flight state based on the vehicle coordinate system, U₂Representing the power input, U, based on the rolling motion of the air-ground amphibious vehicle in flight in the coordinate system of the vehicle₃Representing the power input of pitching motion of an air-ground amphibious vehicle in the flight state based on the vehicle coordinate system, U₄Representing the power input of the land-air amphibious vehicle in the flight state yawing motion based on the vehicle coordinate system; p represents the rolling angular velocity of the vehicle body in the coordinate system of the vehicle,

the rolling angular acceleration of the vehicle body in the vehicle coordinate system is shown, q represents the pitch angular velocity of the vehicle body in the vehicle coordinate system,

representing the pitch angle acceleration of the vehicle body in the vehicle coordinate system, and r representing the yaw angular velocity of the vehicle body in the vehicle coordinate system;

the vehicle body yaw angular acceleration in the vehicle coordinate system is represented.

In one example, referring to fig. 8, there are four main flight actions for the six-rotor drone described above.

Vertical movement: the rotating speeds of the six rotors are increased or reduced simultaneously by changing the accelerator command signal, so that the six-rotor unmanned aerial vehicle can sit on the groundThe sign is vertical movement upwards or downwards, and particularly when the lift force provided by the 6 rotors is equal to the gravity of the six-rotor unmanned aerial vehicle, the six-rotor unmanned aerial vehicle is in a hovering flight state and is in a U shape₁To indicate.

Rolling movement: when a roll command signal is generated, the rotating speeds of the 1, 3 and 5 rotors are increased (or reduced), the rotating speeds of the 2, 4 and 6 rotors are reduced (or increased), and the aerodynamic moments on two sides of the airframe cannot be offset, so that roll torque relative to the airframe axis is generated, the roll motion of the six-rotor unmanned aerial vehicle along the x-axis direction of the airframe is caused, and the U-shaped rotor unmanned aerial vehicle moves along the x-axis direction of the airframe₂To indicate.

Pitching motion: when a pitching command signal is generated, the rotating speeds of the 1 and 2 rotors are increased (or reduced), the rotating speeds of the 4 and 5 rotors are simultaneously reduced (or increased), and the rotating speeds of the 3 and 6 rotors are unchanged, so that a pitching moment relative to the plane body axis is generated, and pitching motion of the six-rotor unmanned plane is caused. When the pitching motion is generated, the horizontal motion of the six-rotor unmanned aerial vehicle along the y-axis direction of the body in the horizontal plane can be caused, and the U-shaped horizontal motion is used as the U-shaped horizontal motion₃To indicate.

Yaw movement: when the counter-clockwise torque generated by the three rotors rotating clockwise and the counter-clockwise torque generated by the three rotors rotating counterclockwise cannot be counteracted, a yaw moment is generated to cause the yaw movement of the aircraft. When there is the driftage command signal, the rotational speed of 1, 3, 5 rotors (positive oar) increases (or reduces), and the rotational speed of 2, 4, 6 rotors (negative oar) reduces (or increases) simultaneously, and the reaction torque size that positive oar and negative oar produced is different to produce the yawing moment around organism z axle, arouse six rotor unmanned aerial vehicle's driftage motion, and with U rotor unmanned aerial vehicle's yawing motion₄To indicate.

To obtain the rotational speed of each rotor motor, the overall rotor lift and torque required to be generated can be distributed using the six-rotor drone's control efficiency matrix, namely:

wherein, c_Ω＝3.5×10^-5Indicating rotary-wing motorsCoefficient of conversion between speed and thrust, M₆Control efficiency matrix, ω, representing a six-rotor drone_aAnd (a 1.. 6) represents the rotation speed of each rotor motor, and a is the number of the rotor.

In order to improve the utilization rate of a rotor motor of an air-ground amphibious vehicle in the landing process, the rotor motor of the air-ground amphibious vehicle is used as an actuator to carry out stability control on the landing process of the air-ground amphibious vehicle, and the rotor lift and the torque required to be provided by a rotor are controlled and distributed through a reasonable control distribution algorithm. For example. The embodiment of the invention mainly adopts a pseudo-inverse method to control and distribute the six rotors so as to achieve the corresponding control effect. Six rotor unmanned aerial vehicle's control efficiency matrix M₆The following were used:

control efficiency matrix M for obtaining six-rotor unmanned aerial vehicle₆Pseudo-inverse of

And the following control distribution is carried out, and the rotating speed of each rotor motor is finally obtained:

wherein, c_rExpressing the lift coefficient of a rotor motor, l expressing the radius of a rotor bracket of an air-ground amphibious vehicle, c_MRepresenting the yaw gain factor of the rotor motor, and F represents the lift generated by the rotor (i.e., F in fig. 8)₁To f₆Sum), M_xRepresenting rotor torque about the x-axis, M_yRepresenting rotor torque about the y-axis, M_zRepresenting rotor torque about the z-axis, and alpha-30 deg. representing half of each horn installation angle.

And obtaining the state updating process of the rotor part of the air-ground amphibious vehicle according to the formula and the information. Referring to FIG. 9, the output information (i.e., body attitude and center of gravity position) of the body and rotor pylon model at time t-1 is used to calculateCalculating lift coefficient c of each rotor motor at time t_T. Meanwhile, the rotating resistance of the rotor at the time t is calculated by utilizing the rotating speed of the rotor at the time t-1, and since the parameter information of the torque of the motor of the rotor is input to a rotor dynamic model by the outside (such as a driver or a controller) at the time t, the rotating acceleration of the rotor at the time t can be calculated and obtained by utilizing the torque of the motor of the rotor at the time t and the rotating resistance of the rotor at the time t, and then the rotating integral of the rotor at the time t is obtained according to the rotating acceleration of the rotor at the time t. Then using the rotor rotation integral at the time t and the lift coefficient c of each rotor motor at the time t_TAnd calculating to obtain the lift force and the moment of the rotor wing at the moment t, and obtaining the rotation speed of the rotor wing at the moment t by utilizing the rotation integral of the rotor wing at the moment t. The lift force and torque of the rotor at the time t and the rotation speed of the rotor at the time t are both used at the time t + 1. And finishing the state updating of the rotor wing part of the air-ground amphibious vehicle.

In another example, a wheel portion of an air-ground amphibious vehicle is analyzed and a state update process is determined. Referring to fig. 10, the angular acceleration of the wheel at time t is obtained by calculating using the longitudinal force of the tire at time t-1, the driving torque and braking torque of the tire (i.e., the mechanical information of the tire) input to the wheel model from the outside (e.g., a driver or a controller) at time t, and the vertical force of the wheel at time t. And then, calculating to obtain a wheel rolling integral by using the angular acceleration of the wheel, and then calculating to obtain the slip rate of the wheel by using the wheel rolling integral and the output information (namely the posture and the gravity center position of the vehicle body and the rotor wing bracket model). And simultaneously, the steering angle (namely, tire steering information) input to the wheel model by the outside (such as a driver or a controller) at the time t and the output information (namely, the vehicle body posture and the gravity center position) of the vehicle body and the rotor bracket model at the time t-1 are utilized to calculate the corresponding slip angle of the wheel. And then calculating and obtaining the tire longitudinal force and the tire lateral force at the time t by utilizing the slip rate of the wheel, the slip angle of the wheel, the wheel vertical force and a magic tire formula, and using the tire longitudinal force and the tire lateral force at the time t + 1.

Referring to fig. 10, the suspension spring force and the suspension damping force at the time t are calculated and obtained by using the output information (namely the vehicle body posture and the gravity center position) of the vehicle body and the rotor bracket model at the time t-1, the vertical position of the wheel at the time t-1 and the vertical speed of the wheel at the time t-1. Meanwhile, the tire spring force at the t moment is calculated and obtained by utilizing the vertical position of the wheel at the t-1 moment, the vertical speed of the wheel at the t-1 moment and the road surface excitation at the t moment. And then calculating and obtaining the acceleration of the wheel at the time t by using the tire spring force at the time t and the suspension spring force and the suspension damping force at the time t. And then, calculating and obtaining a wheel vertical motion integral at the time t by using the acceleration of the wheel at the time t, the wheel vertical position at the time t-1 and the wheel vertical speed at the time t-1. And then, calculating by using the wheel vertical motion integral at the time t to obtain the wheel vertical force, the wheel vertical position and the wheel vertical speed at the time t. And the vertical position of the wheel, the vertical speed of the wheel, the longitudinal force of the tire, the lateral force of the tire, the spring force of the suspension and the damping force of the suspension at the moment t are all used at the moment t + 1. And finishing the state updating of the wheel part of the air-ground amphibious vehicle.

Referring to fig. 10, in the updating process, the parameters of the magic tire formula are obtained through parameter fitting, and the tire lateral force is approximately calculated by using the magic tire formula. And then, the ground supporting force borne by each wheel is analyzed and calculated according to the relative deformation quantity of the tire and the suspension, and the maximum acting force possibly borne by the tire is further obtained. In addition, the spring force (namely the tire spring force) borne by the tire, the suspension spring force and the suspension damping force are calculated, so that the acceleration of the vertical motion of the wheel is obtained by combining road excitation.

In the above process, a plurality of equations of the wheel model are involved. For example, a magic equation of a tire lateral force, a tire support force equation, and a tire vertical dynamics equation in the wheel model.

Exemplarily, the magic equation of the tire lateral force satisfies:

F_yi＝D·sin[C·arctan{Bα_i-E(Bα_i-arctan(Bα_i))}]；

wherein, F_yiRepresenting the lateral force of the tire, B, D and E representing magic formula parameters obtained after parameter fitting, C representing curve shape factor, alpha_iIndicating the tire slip angle.

The tire support force equation satisfies:

the device comprises a left wheel, a right wheel, an air-ground amphibious vehicle, a left front wheel, an air-ground amphibious vehicle, a left rear wheel, an air-ground amphibious vehicle, a right rear wheel, a left front wheel, an air-ground amphibious vehicle, a right front wheel, an air-ground amphibious vehicle, a left rear wheel, an air-ground amphibious vehicle, a right rear wheel, a left rear wheel, an air-ground amphibious; f_Ni(i ═ { fl, fr, rl, rr }) represents the ground support force to which the four wheels of an air-ground amphibious vehicle are subjected, F_NflRepresenting the ground support force to which the left front wheel of an air-ground amphibious vehicle is subjected, F_NfrRepresenting the ground support force on the front right wheel of an air-ground amphibious vehicle, F_NrlRepresenting the ground support force to which the left rear wheel of an air-ground amphibious vehicle is subjected, F_NrrThe ground supporting force borne by the right rear wheel in the air-ground amphibious vehicle is represented; m is_iRepresenting mass, z, of each wheel in an air-ground amphibious vehicle_iThe vertical position of each wheel in the air-ground amphibious vehicle is represented;

representing the speed of each wheel in the air-ground amphibious vehicle;

representing the acceleration of each wheel in the air-ground amphibious vehicle; z'_iThe vertical position of the vehicle body after four vertexes of the vehicle body are linearized in the air-ground amphibious vehicle is represented;

representing the speed of the vehicle body after four vertexes of the vehicle body are linearized in the air-ground amphibious vehicle; c. C_iRepresenting four-wheel suspension damping coefficient; k is a radical of_iThe four-wheel suspension stiffness coefficient is shown.

The vertical kinetic equation of the tire satisfies:

wherein, i ═ { fl, fr, rl, rr } respectively represents four wheels of the air-ground amphibious vehicle, fl represents the left front wheel in the air-ground amphibious vehicle, fr represents the right front wheel in the air-ground amphibious vehicle, rl represents the left rear wheel in the air-ground amphibious vehicle, rr represents the right rear wheel in the air-ground amphibious vehicle, and m represents the left rear wheel in the air-ground amphibious vehicle_iRepresenting mass, z, of each wheel in an air-ground amphibious vehicle_iThe vertical position of each wheel in the air-ground amphibious vehicle is represented;

representing the speed of each wheel in the air-ground amphibious vehicle;

representing the speed of the vehicle body after four vertexes of the vehicle body are linearized in the air-ground amphibious vehicle; c. C_iRepresenting four-wheel suspension damping coefficient; k is a radical of_iRepresenting the stiffness coefficient of the four-wheel suspension; k is a radical of_tRepresenting a tire stiffness coefficient; q. q.s_iIndicating road surface excitation.

In yet another example, body and rotor pylon portions of an air-ground amphibious vehicle are analyzed and a state update process is determined. Referring to fig. 11, after the analysis of the wheel parts is completed, longitudinal force and lateral force of the whole body are analyzed by using a body and rotor bracket model and a double-rail model, and the acceleration in each direction and the angular acceleration of the yaw motion are obtained according to newton's law of motion. And then analyzing the vertical direction, the pitching motion and the rolling motion of the vehicle body by using a 7-degree-of-freedom suspension model of the whole vehicle.

The above-mentioned 7 degrees of freedom refer to the up-and-down movement of the vehicle body along the Z-axis, the roll along the X-axis, the pitch along the Y-axis, and the unsprung portion of the suspension (mainly the up-and-down bounce of the tire).

In this process, a plurality of equations for the model of the body and the rotor support are involved. For example, body vertical dynamics equations, body pitch dynamics equations, and body roll dynamics equations, body total longitudinal force equations, body total lateral force equations, and yaw moment equations in the body and rotor pylon models.

The above-mentioned total longitudinal force equation of the automobile body satisfies:

the above-mentioned car body total lateral force equation satisfies:

∑_iF_Qi＝(M_b+M_r+4m_i)a_y；

the yaw moment equation satisfies:

therein, sigma_iF_LiRepresents the total longitudinal force, sigma, of the body of the air-ground amphibious vehicle_iF_QiRepresenting the total lateral force of the body of the air-ground amphibious vehicle; and i, wherein { fl, fr, rl and rr } respectively represent four wheels of the air-ground amphibious vehicle, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, and rr represents a right rear wheel in the air-ground amphibious vehicle.

Representing the air resistance of the air-ground amphibious vehicle during driving, c_wRepresenting the air resistance coefficient, rho representing the air density parameter, A representing the windward area of the air-ground amphibious vehicle, v_xRepresenting the speed of the moving direction of the air-ground amphibious vehicle during running; j. the design is a square_zRepresenting moment of inertia, M, about the z-axis of an air-ground amphibious vehicle relative to the center of mass_bRepresenting the mass of the body in an air-ground amphibious vehicle, M_rRepresenting the mass of a rotor in an air-ground amphibious vehicle, m_iRepresenting the mass of each wheel in an air-ground amphibious vehicle, a_xRepresenting the longitudinal acceleration of the air-ground amphibious vehicle; a is_yRepresenting the lateral acceleration of the air-ground amphibious vehicle; u shape₄Expressing the power input, L, based on the yaw motion of the air-ground amphibious vehicle in the flight state_fIndicating the distance, L, from the center of the air-ground amphibious vehicle to the front axle_rThe distance from the center of the air-ground amphibious vehicle to the rear axle is shown, b represents the wheel track (in the embodiment of the invention, the wheel tracks of the front axle and the rear axle are assumed to be the same),

representing half of the center distance of the left and right wheels in an air-ground amphibious vehicle, F_LflRepresenting the longitudinal force, F, to which the wheels fl of an air-ground amphibious vehicle are subjected_LfrRepresenting longitudinal forces, F, to which wheels fr of an air-ground amphibious vehicle are subjected_LrlRepresenting the longitudinal force, F, experienced by the wheels rl of an air-ground amphibious vehicle_LrrRepresenting the longitudinal force, F, experienced by the wheels rr of an air-ground amphibious vehicle_QrlRepresenting the lateral force, F, experienced by the wheels fl of an air-ground amphibious vehicle_QfrRepresenting lateral forces, F, to which wheels fr of an air-ground amphibious vehicle are subjected_QrlRepresenting the lateral force, F, experienced by the wheels rl of an air-ground amphibious vehicle_QrrThe lateral force received by the wheels rr of the air-ground amphibious vehicle is shown, and r represents the vehicle body yaw angular velocity in the vehicle coordinate system.

The yaw moment equation is a differential equation of the yaw movement of the vehicle after considering the yaw moment generated by the input of the rotor and the contact of the tire with the ground.

Sigma above_iF_LiAnd Σ_iF_QiThe longitudinal force F of the vehicle body of the air-ground amphibious vehicle can be obtained through calculation from the vehicle body stress analysis chart in the figure 11_LiBody side force F of air-ground amphibious vehicle_Qi。

F_Li＝F_xi cos(δ_i)-F_yi sin(δ_i)；

F_Qi＝F_xisin(δ_i)+F_yicos(δ_i)。

Wherein, delta_iIndicates the steering angle, F, of the tire i_xiIndicating longitudinal force of wheel，F_yiThe lateral force of the tire is represented, i ═ { fl, fr, rl, rr } represents four wheels of the air-ground amphibious vehicle respectively, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, and rr represents a right rear wheel in the air-ground amphibious vehicle.

The above analysis of the vertical, pitch and roll motions of the vehicle body is performed using a 7-degree-of-freedom suspension model of the entire vehicle, as shown in fig. 12.

Wherein m is_tDenotes the mass of the tire, k_tExpressing the coefficient of stiffness, k, of the tire_sRepresenting suspension damper stiffness, c_sIndicating the damping coefficient, Z, of the suspension shock absorber_iThe vertical positions of four wheels in the air-ground amphibious vehicle under the global coordinate system are represented;

representing the speeds of four wheels in the air-ground amphibious vehicle under a global coordinate system; z'_iThe vertical position of the four vertexes of the vehicle body in the air-ground amphibious vehicle after linearization under the global coordinate system is represented;

representing the speed of the vehicle body after four vertexes of the vehicle body are linearized in the air-ground amphibious vehicle under the global coordinate system; q. q.s_iThe road excitation is represented, i ═ { fl, fr, rl, rr } respectively represents four wheels of an air-ground amphibious vehicle, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, and rr represents a right rear wheel in the air-ground amphibious vehicle.

The formula is based on the small angle hypothesis of the pitch angle and the roll angle in the global coordinate system, and the vertical motion analysis of the air-ground amphibious vehicle in the global coordinate system can approximate the vertical motion of the equivalent air-ground amphibious vehicle in the vehicle coordinate system.

The vehicle body vertical kinetic equation, the vehicle body pitching kinetic equation and the vehicle body side rolling kinetic equation can be obtained by utilizing the whole vehicle 7-degree-of-freedom suspension model and combining the force action of the middle rotor part. Note that the three equations herein are processed based on a global coordinate system.

The vertical kinetic equation of the vehicle body meets the following requirements:

the vehicle body pitching kinetic equation satisfies the following conditions:

the above-mentioned vehicle body heeling kinetic equation satisfies:

wherein M is_bRepresenting the mass of the body in an air-ground amphibious vehicle, g representing the acceleration of gravity, Z_bRepresenting the vertical position of the mass center of the air-ground amphibious vehicle under a global coordinate system, (supplementary explanation, z)_bRepresenting the vertical position of the center of mass of the air-ground amphibious vehicle under the coordinate system of the vehicle) Z_iThe vertical positions of four wheels in the air-ground amphibious vehicle are represented;

representing the speed of the vehicle body after four vertexes of the vehicle body are linearized in the air-ground amphibious vehicle under the global coordinate system; c. C_iRepresenting four-wheel suspension damping coefficient; k is a radical of_iTo representFour-wheel suspension stiffness coefficient; b represents the track width of the wheel,

the center distance of the left wheel and the right wheel in the air-ground amphibious vehicle is half; l denotes the rotor pylon radius of an air-ground amphibious vehicle,

the acceleration (namely roll acceleration) of the air-ground amphibious vehicle rotating around the X axis in the global coordinate system is represented;

the acceleration (namely the pitching acceleration) representing the rotation of the air-ground amphibious vehicle around the Y axis in the global coordinate system; l is_fRepresenting the distance from the center of the air-ground amphibious vehicle to the front axle; l is_rRepresenting the distance from the center of the air-ground amphibious vehicle to the rear axle; u shape₁Representing the power input of the land-air amphibious vehicle in the vertical motion in the flight state based on the vehicle coordinate system, U₂Representing the power input, U, based on the rolling motion of the air-ground amphibious vehicle in flight in the coordinate system of the vehicle₃Representing the power input of pitching motion of an air-ground amphibious vehicle in the flight state based on the vehicle coordinate system, U₄Representing the power input of the land-air amphibious vehicle in the flight state yawing motion based on the vehicle coordinate system; j. the design is a square_xRepresenting the moment of inertia, J, about the x-axis of the amphibious vehicle relative to the center of mass_yRepresenting the moment of inertia about the y-axis of the air-ground amphibious vehicle relative to the center of mass. And i, wherein { fl, fr, rl and rr } respectively represent four wheels of the air-ground amphibious vehicle, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, and rr represents a right rear wheel in the air-ground amphibious vehicle.

When the pitch angle θ and the roll angle Φ are varied within a very small range, the following equation system can be obtained:

Z_fl′＝Z_b-L_fθ+bφ；

Z_fr′＝Z_b-L_fθ-bφ；

Z_rl′＝Z_b+L_rθ+bφ；

Z_rr′＝Z_b+L_rθ-bφ；

wherein Z is_fl' represents the vertical position of the connecting point of the vehicle suspension and the left front part of the vehicle body after linear simplification under a global coordinate system, Z_fr' represents the vertical position of the connecting point of the vehicle suspension and the right front part of the vehicle body after linear simplification under a global coordinate system, Z_rl' represents the vertical position of the connecting point of the vehicle suspension and the left rear part of the vehicle body after linear simplification under a global coordinate system, Z_rr' denotes the vertical position of the connection point of the vehicle suspension and the right rear of the vehicle body after linear simplification under the global coordinate system, Z_bRepresents the vertical position L of the mass center of the air-ground amphibious vehicle under the global coordinate system_fRepresenting the distance from the center of the air-ground amphibious vehicle to the front axle; l is_rRepresenting the distance from the center of the air-ground amphibious vehicle to the rear axle; b represents the wheel track, phi represents the rolling angle of the air-ground amphibious vehicle around the X axis in the global coordinate system, and theta represents the pitch angle of the air-ground amphibious vehicle around the Y axis in the global coordinate system.

Fig. 13 shows a schematic view of state updating of a body and a rotor bracket part of an air-ground amphibious vehicle provided by the embodiment of the invention. Referring to fig. 13, output information (i.e., vehicle body posture and gravity center position) of the vehicle body and rotor support model at the time t-1, steering angle (i.e., tire steering information) and tire driving torque and tire braking torque (i.e., tire mechanical information) provided by the outside (e.g., a driver or a controller) at the time t, and road excitation at the time t are input into the wheel model, and tire longitudinal force, tire lateral force, suspension spring force and suspension damping force at the time t are calculated. Meanwhile, the output information (namely the posture and the gravity center position of the vehicle body and the rotor bracket model) at the time t-1 and the rotor motor torque provided by the outside (such as a driver or a controller) at the time t are input into the rotor model to calculate and obtain the rotor lift force and the torque at the time t and the rotor rotation speed. Then, the tire longitudinal force, the tire lateral force, the suspension spring force, the suspension damping force, the rotor lift force and moment and the rotor rotation speed at the time t obtained through calculation are converted into a vehicle coordinate system b (O-XYZ) through a global coordinate system n (O-XYZ), and then the vehicle body angular acceleration of the vehicle coordinate system at the time t is obtained through calculation. Then, the rotational degree of freedom integral of the vehicle body in the vehicle coordinate system at the time t is obtained by utilizing the vehicle body angular acceleration calculation of the vehicle coordinate system at the time t (namely, local attitude updating is carried out), and then the rotational degree of freedom integral of the vehicle body in the vehicle coordinate system at the time t is converted into a global coordinate system n (O-XYZ) from a vehicle coordinate system b (O-XYZ), so that the vehicle body attitude at the time t is obtained.

Referring to fig. 13, the acceleration of the vehicle body under the global coordinate system at the time t is further calculated and obtained by utilizing the tire longitudinal force, the tire lateral force, the suspension spring force, the suspension damping force, the rotor lifting force and moment, the rotor rotation speed and the gravity at the time t. And then calculating and obtaining the integral of the translation freedom degree of the vehicle body at the time t under the global coordinate system by using the acceleration at the time t. And then, obtaining the gravity center position at the time t by utilizing the integral of the translation freedom degree of the vehicle body at the time t in the global coordinate system. The vehicle body posture at the time t and the gravity center position at the time t are both used at the time t + 1. And finishing the state updating of the body and the rotor wing bracket part of the air-ground amphibious vehicle. Namely, according to the vehicle body state at the previous moment and the input at the current moment, the wheel model and the rotor wing model are updated, and then the updated quantity is input into the vehicle body and the rotor wing bracket model for updating, and the process is repeated.

In summary, the overall state updating process of the air-ground amphibious vehicle can be known through analysis of the motions of the vehicle body, the rotor, the suspension and the wheels according to the vehicle body 6 degrees of freedom (for example, 3 translation and 3 rotation of the vehicle body in the global coordinate system), the rotor single degree of freedom (for example, rotation of the rotor) and the suspension tire 2 degrees of freedom (for example, the vertical degree of freedom and the steering degree of freedom (namely, steering angle) of the wheels in the vehicle coordinate system) described in the foregoing.

Because the air-ground amphibious vehicle in the simulation environment is a dynamic model, in the actual application process, the real air-ground amphibious vehicle needs to be modeled first. For example, three-dimensional modeling is performed in SolidWorks and a three-dimensional model file (i.e., a mesh file) is derived. The mesh file mainly comprises a vehicle body, wheels and a rotor wing. After modeling of the real air-ground amphibious vehicle is completed, an ROS Package is created, a robot description file (namely a URDF file) is written according to a simulation model of the real air-ground amphibious vehicle, and the three-dimensional modeling completed in SolidWorks can be displayed in a Gazebo through the URDF file. And then writing the CMakeLists and the Package files according to the dependencies (for example, if a certain library is called by a code at a certain position in the ROS Package, the library needs to be declared as the dependencies in the CMakeLists and the Package files, otherwise, the compiling fails). In the URDF document, the wheels and rotors are connected to the vehicle body by a continuous joint. Parameters such as corresponding rotational inertia, the mass of a vehicle body in the air-ground amphibious vehicle, the mass of wheels and the mass of rotors can be obtained by SolidWorks calculation. The simulation environment in the simulation platform can be constructed in a mode of generating mesh, writing SDF and world files. The simulation environment in the embodiment of the present invention is modified based on citysim provided by OSRF (open source robot foundation).

And then, simulating and moving the air-ground amphibious vehicle in a simulation environment. The above simulations include flight part simulation and ground part (chassis) simulation. Specifically, the flight part simulation is realized by means of an air-ground amphibious vehicle simulation ROS Package. For example, the flight part may adopt a six-rotor air-ground amphibious vehicle model, implement basic fixed-point flight by using lee _ position _ controller (fixed-point flight controller) in the ground-air amphibious vehicle simulation ROS Package, and adjust relevant parameters in a parameter file of lee _ position _ controller to optimize flight performance, or self-write a fixed-point flight controller by using controller library (controller library) provided by the ground-air amphibious vehicle simulation ROS Package. The lee _ position _ controller uses a rotorcraft built-in rotor dynamics model, and self-programming controllers are needed to apply the rotor dynamics model proposed herein. When the universal adapter is used, a RotorS sensor, a MAVLink (Micro Air Vehicle Link, Micro Air Vehicle Link communication protocol) Interface and other necessary plug-ins need to be added into the URDF file.

The principle of the above process is: gazebo plug-ins such as odometers and inertial navigation modules in the ground-air amphibious vehicle simulation ROS Package are used for simulating sensor data, the rotating speed of each motor is calculated by combining the sensor data and a ground-air amphibious vehicle dynamics model according to an input target pose through a fixed-point flight controller, and finally the Gazebo plug-ins of the motors are output, so that flight under the Gazebo simulation environment is realized. Here the air-ground amphibious vehicle emulates the ROS Package primarily to function as a Gazebo plug-in. The lee-position-controller serving as a default control algorithm for simulating the ROS Package of the air-ground amphibious vehicle has the advantages of being convenient to use, but can be replaced by other ROS-based written controllers for further development later. Meanwhile, the ROS Package for simulating the land-air amphibious vehicle also provides a set of controller library, and a controller can be developed based on a template provided by the ROS Package.

The above-described air-ground amphibious vehicle simulation ROS Package may also function as a Gazebo plug-in providing the necessary sensors (e.g., odometer, IMU, GPS, etc.) for flight segment simulation and a fixed point flight controller lee _ position _ controller (or controller library for writing custom fixed point flight controllers). Meanwhile, the Gazebo plug-in and the lee _ position _ controller and the controller library are not in binding relationship and may be replaced by other controllers. The ROS Package has the advantages that a relatively complete integration is provided for the simulation of the ground-air amphibious vehicle, and meanwhile, the interface of the ROS Package is designed to be as close to a real system as possible, so that a developer can switch between simulation and the real world conveniently. The embodiment of the invention only provides a feasible scheme by using the ROS Package for simulating the air-ground amphibious vehicle, and other ROS packages compiled for the simulation of the air-ground amphibious vehicle such as a sector _ quadrator are also available. It should be understood that the flight control implemented by the air-ground amphibious vehicle simulation ROS Package developed by the ETHZ described above, wherein the air-ground amphibious vehicle simulation ROS Package provides Gazebo plug-ins such as inertial navigation module, motor control, etc. and basic fixed point flight controller and controller library necessary for the air-ground amphibious vehicle to fly.

The chassis Control of the ground segment is written based on ROS Control. The chassis may use an Ackermann chassis (Ackermann chassis) and write control nodes according to the Ackermann steering model. Wherein the format of the ROS message (i.e., message) uses ackermann _ msgs, and the control node is written according to a vehicle dynamics model. And calculating the speed and the angle of each wheel of rotating shaft in the node, and respectively controlling through ROS Control. Of course, the chassis may also adopt a chassis such as a differential steering model (e.g., a ski-steer), and the Control may also be realized based on the ROS Control. The use of ROS Control in Gazebo requires the addition of a corresponding Gazebo insert in the URDF. Specifically, an Ackermann chassis controller written based on ROS Control controls the steering of front wheels and the four-wheel speed after calculation by issuing the steering and speed information of the whole vehicle to the controller node.

Further, the sensing part (which refers to acquiring sensing information through a sensor simulated by a virtual sensor arranged on the simulation platform, namely a Gazebo plug-in) utilizes an existing ROS Package and adds a corresponding item in the URDF. For example, a multiline lidar (e.g., Velodyne HDL-32E lidar), color, infrared, and depth cameras (e.g., Kinect V2 camera), etc. are added to the URDF, and a single axis pan-tilt head is attached to the camera using ROS Control. More functionality can be achieved by combining with a package such as OctMap, Loam, etc. The sensing part is realized by utilizing a Gazebo plug-in, and in the embodiment of the invention, the simulation truth can be improved by setting the sensor parameters according to the real objects, but the sensing part is not limited to the two types of sensors. Further functionality is achieved by using or writing other ROS nodes or ROS packages, e.g. 3D mapping using OctoMap. After the ROS and Gazebo parts are configured, the simulation platform is started through the launch file during use, and nodes and related parameters needing to be started are preset in the launch file.

While the invention has been described in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a review of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

While the invention has been described in conjunction with specific features and embodiments thereof, it will be evident that various modifications and combinations can be made thereto without departing from the spirit and scope of the invention. Accordingly, the specification and figures are merely exemplary of the invention as defined in the appended claims and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A multi-modal air-ground amphibious vehicle platform simulation system is characterized by comprising: a simulation platform and a motion controller in communication with the simulation platform; the simulation platform comprises a simulation environment and an air-ground amphibious vehicle positioned in the simulation environment; the description model of the air-ground amphibious vehicle comprises a coupled flight dynamic model and a vehicle dynamic model;

the motion controller is used for sending a control instruction to the simulation platform according to the motion instruction;

the simulation platform is used for controlling the air-ground amphibious vehicle to operate in the simulation environment according to the control instruction;

the motion controller is also used for collecting perception information of the simulation platform and updating the control instruction according to the perception information; the perception information comprises the state of the simulation environment and the state of the air-ground amphibious vehicle.

2. The multi-modal air-ground amphibious vehicle platform simulation system of claim 1, wherein the motion controller and the simulation platform comprise a software-in-the-loop simulation system.

3. The multi-modal air-ground amphibious vehicle platform simulation system of claim 1, wherein the motion controller and the simulation platform form a hardware-in-the-loop simulation system.

4. The multi-modal air-ground amphibious vehicle platform simulation system according to claim 1, wherein the air-ground amphibious vehicle simulation system is a visual simulation system.

5. The multi-modal air-ground amphibious vehicle platform simulation system according to claim 1, wherein the motion controller comprises:

the sensing module is communicated with the air-ground amphibious vehicle and is used for acquiring sensing information of the simulation platform;

the control module is communicated with the sensing module and the air-ground amphibious vehicle and is used for controlling the air-ground amphibious vehicle to operate in the simulation environment according to the motion instruction; and controlling the air-ground amphibious vehicle to operate in the simulation environment according to the perception information.

6. The multi-modal air-ground amphibious vehicle platform simulation system according to any one of claims 1-5, wherein the control commands comprise wheel control information and rotor control information.

7. A multi-modal air-ground amphibious vehicle platform simulation system according to any one of claims 1-5, wherein the air-ground amphibious vehicle is a flying vehicle, the flying vehicle comprises a vehicle and a rotor provided on the vehicle, and the vehicle comprises a suspension and wheels provided on the suspension.

8. A multi-modal air-ground amphibious vehicle platform simulation system according to any one of claims 1-5, wherein the flight dynamics model is a rotor dynamics model, the vehicle dynamics model comprises a wheel model and a body and rotor pylon model, and the body and rotor pylon model is mutually coupled with the wheel model and the rotor dynamics model respectively.

9. The multi-modal air-ground amphibious vehicle platform simulation system of claim 8,

the input information of the wheel model comprises tire steering information, tire mechanical information and output information of the vehicle body and rotor wing bracket model; the output information of the wheel model comprises suspension spring force, suspension damping force, tire longitudinal force and tire lateral force;

the input information of the rotor wing dynamic model comprises rotor wing motor torque and the output information of the vehicle body and the rotor wing bracket model; the output information of the rotor wing dynamic model comprises rotor wing lift force and moment, and rotor wing rotation speed;

the input information of the vehicle body and rotor support model comprises the output information of the wheel model and the output information of the rotor dynamic model.

10. The multi-modal air-ground amphibious vehicle platform simulation system according to claim 8, wherein the rotor dynamics model satisfies the following system of equations:

wherein, K₁Denotes the first aerodynamic damping parameter, K₂Representing a second aerodynamic damping parameter, K₃Represents a third aerodynamic damping parameter, K₄Denotes a fourth aerodynamic damping parameter, K₅Denotes a fifth aerodynamic damping parameter, K₆Represents a sixth aerodynamic damping parameter; m_rRepresenting the mass of a rotor wing in the air-ground amphibious vehicle, and g representing the gravity acceleration; v_XRepresenting the speed, V, of the air-ground amphibious vehicle in the X-axis direction in a global coordinate system_YRepresenting the speed, V, of the air-ground amphibious vehicle in the Y-axis direction in a global coordinate system_ZRepresenting the speed of the air-ground amphibious vehicle in the Z-axis direction in a global coordinate system;

represents the acceleration of the air-ground amphibious vehicle in the X-axis direction in a global coordinate system,

represents the acceleration of the air-ground amphibious vehicle in the Y-axis direction in a global coordinate system,

representing the acceleration of the air-ground amphibious vehicle in the Z-axis direction in a global coordinate system; phi represents a rolling angle of the air-ground amphibious vehicle around an X axis in a global coordinate system, theta represents a pitch angle of the air-ground amphibious vehicle around a Y axis in the global coordinate system, and psi represents a yaw angle of the air-ground amphibious vehicle around a Z axis in the global coordinate system; j. the design is a square_xRepresenting the moment of inertia, J, about the x-axis of the air-ground amphibious vehicle relative to the center of mass_yRepresenting the moment of inertia, J, about the y-axis of the air-ground amphibious vehicle relative to the center of mass_zRepresenting a moment of inertia about the air-ground amphibious vehicle z-axis relative to a center of mass; l represents the rotor bracket radius of the air-ground amphibious vehicle; u shape₁Representing the power input of the air-ground amphibious vehicle in the vertical motion in the flight state based on the vehicle coordinate system, U₂Representing the power input, U, of the air-ground amphibious vehicle in the rolling motion in flight based on the vehicle coordinate system₃Representing the power input of the pitching motion of the air-ground amphibious vehicle in the flight state based on the vehicle coordinate system, U₄Representing the power input of the air-ground amphibious vehicle in the flight state yaw motion based on the vehicle coordinate system; p represents the rolling angular velocity of the vehicle body in the coordinate system of the vehicle,

representing the vehicle body yaw angular acceleration in the vehicle coordinate system;

the wheel model includes: magic equation of tire lateral force, tire support force equation and tire vertical dynamics equation;

the magic equation of the lateral force of the tire satisfies the following conditions:

F_yi＝D·sin[C·arctan{Bα_i-E(Bα_i-arctan(Bα_i))}]；

wherein, F_yiRepresenting the lateral force of the tire, B, D and E representing magic formula parameters obtained after parameter fitting, C representing curve shape factor, alpha_iRepresents a tire slip angle;

the tire support force equation satisfies:

wherein, i ═ { fl, fr, rl, rr } respectively represents four wheels of the air-ground amphibious vehicle, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, and rr represents a right rear wheel in the air-ground amphibious vehicle; f_Ni(i ═ { fl, fr, rl, rr }) represents the ground support force to which the four wheels of the air-ground amphibious vehicle are subjected, F_NflRepresenting the ground support force borne by the left front wheel in the air-ground amphibious vehicle, F_NfrRepresenting the ground support force borne by the front right wheel in the air-ground amphibious vehicle, F_NrlRepresenting the ground support force borne by the left rear wheel in the air-ground amphibious vehicle, F_NrrRepresenting the ground supporting force borne by the right rear wheel in the air-ground amphibious vehicle; m is_iRepresenting the mass of each wheel in the air-ground amphibious vehicle, and zi representing the vertical position of each wheel in the air-ground amphibious vehicle;

representing a speed of each wheel in the air-ground amphibious vehicle;

representing an acceleration of each wheel in the air-ground amphibious vehicle; z'_iRepresenting the vertical position of the vehicle body after four vertexes of the vehicle body are linearized in the air-ground amphibious vehicle;

representing the speed of the air-ground amphibious vehicle after four vertexes of the vehicle body are linearized; c. C_iRepresenting four-wheel suspension damping coefficient; k is a radical of_iRepresenting the stiffness coefficient of the four-wheel suspension;

the vertical kinetic equation of the tire satisfies:

wherein, i ═ { fl, fr, rl, rr } respectively represents four wheels of the air-ground amphibious vehicle, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, rr represents a right rear wheel in the air-ground amphibious vehicle, and m represents a left rear wheel in the air-ground amphibious vehicle_iRepresenting the mass, z, of each wheel in the air-ground amphibious vehicle_iRepresenting a vertical position of each wheel in the air-ground amphibious vehicle;

representing a speed of each wheel in the air-ground amphibious vehicle;

representing the speed of the air-ground amphibious vehicle after four vertexes of the vehicle body are linearized; c. C_iRepresenting four-wheel suspension damping coefficient; k is a radical of_iRepresenting the stiffness coefficient of the four-wheel suspension; k is a radical of_tRepresenting a tire stiffness coefficient; q. q.s_iRepresenting road surface excitation;

the automobile body and rotor support model includes: the system comprises a vehicle body vertical dynamic equation, a vehicle body pitching dynamic equation, a vehicle body rolling dynamic equation, a vehicle body total longitudinal force equation, a vehicle body total lateral force equation and a yawing moment equation;

the vertical kinetic equation of the vehicle body satisfies the following conditions:

the vehicle body pitch kinetic equation satisfies:

the vehicle body roll kinetic equation satisfies:

wherein M is_bRepresenting the mass of the vehicle body in the air-ground amphibious vehicle, g representing the gravitational acceleration, Z_bRepresents the vertical position of the mass center of the air-ground amphibious vehicle under a global coordinate system, Z_iRepresenting the vertical positions of four wheels in the air-ground amphibious vehicle under a global coordinate system;

representing the speeds of four wheels in the air-ground amphibious vehicle under a global coordinate system; z'_iRepresenting the vertical position of the vehicle body after four vertexes of the vehicle body are linearized in the air-ground amphibious vehicle under a global coordinate system;

representing the speed of the air-ground amphibious vehicle after four vertexes of the vehicle body are linearized in a global coordinate system; c. C_iRepresenting four-wheel suspension damping coefficient; k is a radical of_iRepresenting the stiffness coefficient of the four-wheel suspension; b represents the track width of the wheel,

representing half of the center distance of left and right wheels in the air-ground amphibious vehicle; l denotes the rotor pylon radius of the air-ground amphibious vehicle,

representing the air-ground amphibious vehicleAcceleration of the vehicle rotating about the X-axis in the global coordinate system;

representing the acceleration of the air-ground amphibious vehicle rotating around the Y axis in the global coordinate system; l is_fRepresenting the distance from the center of the air-ground amphibious vehicle to a front axle; l is_rRepresenting the distance from the center of the air-ground amphibious vehicle to a rear axle; u shape₁Representing the power input of the air-ground amphibious vehicle in the vertical motion in the flight state based on the vehicle coordinate system, U₂Representing the power input, U, of the air-ground amphibious vehicle in the rolling motion in flight based on the vehicle coordinate system₃Representing the power input of the pitching motion of the air-ground amphibious vehicle in the flight state based on the vehicle coordinate system, U₄Representing the power input of the air-ground amphibious vehicle in the flight state yaw motion based on the vehicle coordinate system; j. the design is a square_xRepresenting the moment of inertia, J, about the x-axis of the air-ground amphibious vehicle relative to the center of mass_yRepresenting a moment of inertia about the y-axis of the air-ground amphibious vehicle relative to a center of mass; the i ═ fl, fr, rl, rr respectively represent four wheels of the air-ground amphibious vehicle, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, and rr represents a right rear wheel in the air-ground amphibious vehicle;

the total longitudinal force equation of the vehicle body satisfies the following conditions:

the total lateral force equation of the vehicle body satisfies the following conditions:

∑_iF_Qi＝(M_b+M_r+4m_i)a_y；

the yaw moment equation satisfies:

therein, sigma_iF_LiRepresents the total longitudinal force, sigma of the body of the air-ground amphibious vehicle_iF_QiRepresenting a total lateral force of a vehicle body of the air-ground amphibious vehicle; the i ═ fl, fr, rl, rr respectively represent four wheels of the air-ground amphibious vehicle, fl represents a left front wheel in the air-ground amphibious vehicle, fr represents a right front wheel in the air-ground amphibious vehicle, rl represents a left rear wheel in the air-ground amphibious vehicle, and rr represents a right rear wheel in the air-ground amphibious vehicle;

representing the air resistance of the air-ground amphibious vehicle during driving, c_wRepresenting the air resistance coefficient, rho representing the air density parameter, A representing the windward area of the air-ground amphibious vehicle, v_xRepresenting the speed of the movement direction of the air-ground amphibious vehicle during running; j. the design is a square_zRepresenting the moment of inertia, M, about the z-axis of the air-ground amphibious vehicle relative to the center of mass_bRepresenting the mass, M, of a body in said air-ground amphibious vehicle_rRepresenting the mass m of a rotor in said air-ground amphibious vehicle_iRepresenting the mass of each wheel in the air-ground amphibious vehicle, a_xRepresenting a longitudinal acceleration of the air-ground amphibious vehicle; a is_yRepresenting a lateral acceleration of the air-ground amphibious vehicle; u shape₄Representing the power input, L, of the air-ground amphibious vehicle in the flight state for yaw motion based on the vehicle coordinate system_fRepresents the distance from the center of the air-ground amphibious vehicle to the front axle, L_rRepresenting the distance from the center of the air-ground amphibious vehicle to the rear axle,

representing half of the center distance of the left and right wheels in the air-ground amphibious vehicle, F_LflRepresenting the longitudinal force, F, to which the wheels fl of the air-ground amphibious vehicle are subjected_LfrRepresenting the longitudinal force, F, to which the wheels fr of the air-ground amphibious vehicle are subjected_LrlRepresenting the longitudinal force, F, experienced by the wheels rl of said air-ground amphibious vehicle_LrrRepresenting a wheel rr of said air-ground amphibious vehicleSubjected to a longitudinal force, F_QflRepresenting the lateral force, F, to which the wheels fl of the air-ground amphibious vehicle are subjected_QfrRepresenting the lateral force, F, to which the wheels fr of the air-ground amphibious vehicle are subjected_QrlRepresenting the lateral force, F, experienced by the wheels rl of said air-ground amphibious vehicle_QrrAnd the lateral force borne by the wheels rr of the air-ground amphibious vehicle is shown, and r represents the vehicle body yaw angular speed in the vehicle coordinate system.