A multi-source coupled skateboard chassis system and its coordinated control method

Abstract

The present invention discloses a multi-source coupled skateboard chassis system and a coordinated control method thereof, belonging to the technical field of vehicle skateboard chassis systems, comprising: a wire-controlled drive subsystem, an electro-hydraulic composite wire-controlled steering subsystem, an electrical composite wire-controlled brake subsystem and a coordinated domain control module; the present invention integrates all-wheel drive, steering, braking and other systems into a skateboard chassis system and performs coordinated control on them, thereby solving the problems of control coupling and mutual interference of the various subsystems of the skateboard chassis, while taking into account vehicle uncertainty and time-varying parameters, and can maximize the effectiveness of vehicle dynamic stability control.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle skateboard chassis systems, and particularly relates to a multi-source coupled skateboard chassis system and a coordinated control method thereof. Background Art

[0002] Inspired by new energy logistics policies, electrification has become a key driver of the transformation and upgrade of my country's road transportation, and a trillion-yuan electric truck market has emerged. However, current electric truck chassis systems suffer from issues such as modularity, platformization, and low levels of control-by-wire, significantly limiting the pace of truck electrification. Furthermore, existing chassis systems implement lateral, longitudinal, and vertical vector control entirely through the wheels, leading to coupled and interfering control of chassis subsystems. Furthermore, vehicle uncertainty and time-varying parameters impair vehicle stability control, making coordinated vector control of subsystems difficult. Therefore, designing a rational coordinated control method for skateboard chassis systems to achieve enhanced vehicle handling stability remains a key research topic for designers.

[0003] At present, there are relatively few studies on skateboard chassis, and most of the research on chassis focuses on fault diagnosis and health status. For example, Chinese invention patent application number CN202210047403.6 discloses an integrated universal electric chassis multi-objective collaborative fault diagnosis method and system, which uses a multi-objective collaborative fault diagnosis model to perform real-time online monitoring of each module in the chassis to be tested, thereby improving the efficiency of fault diagnosis; Chinese invention patent application number CN202210047485.4 discloses a multi-objective collaborative health management method and system for an electric chassis, which realizes the automated comprehensive judgment of the health status of the electric chassis. However, the above-mentioned control algorithms cannot solve the problems of control coupling and mutual interference among the various subsystems of the chassis. Therefore, it is essential to accurately establish a chassis system model and adopt a suitable control algorithm to collaboratively control the chassis system. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a multi-source coupled skateboard chassis system and a coordinated control method thereof, so as to overcome the problems existing in the prior art of low level of universalization, integration and wire control of chassis systems, cross-subsystem control and functional interference.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] The multi-source coupled skateboard chassis system of the present invention comprises: a drive-by-wire subsystem, an electro-hydraulic composite steering-by-wire subsystem, an electric composite brake-by-wire subsystem and a collaborative domain control module; wherein,

[0007] The drive-by-wire subsystem includes: an accelerator pedal, an accelerator pedal position sensor, a left front wheel hub motor, a right front wheel hub motor, a left rear wheel hub motor, a right rear wheel hub motor, a left front wheel speed sensor, a right front wheel speed sensor, a left rear wheel speed sensor, a right rear wheel speed sensor, a left front wheel, a right front wheel, a left rear wheel, a right rear wheel, and a drive-by-wire control module; the accelerator pedal position sensor is fixedly mounted on the accelerator pedal for sending an accelerator pedal position signal to the drive-by-wire control module; the left front wheel hub motor and the left front wheel speed sensor are mounted in the left front wheel; the right front wheel hub motor and the right front wheel speed sensor are mounted in Inside the right front wheel; the left rear wheel hub motor and the left rear wheel speed sensor are installed in the left rear wheel; the right rear wheel hub motor and the right rear wheel speed sensor are installed in the right rear wheel; the rotational motion output by the left front wheel hub motor, the right front wheel hub motor, the left rear wheel hub motor and the right rear wheel hub motor are respectively converted into the rotational motion of the left front wheel, the right front wheel, the left rear wheel and the right rear wheel to drive the vehicle; the input end of the drive-by-wire control module is connected to the left front wheel speed sensor, the right front wheel speed sensor, the left rear wheel speed sensor and the right rear wheel speed sensor through the on-board communication line, and the output end of the drive-by-wire control module is connected to the collaborative domain control module;

[0008] The electro-hydraulic composite wire-controlled steering subsystem includes: a steering wheel module, a steering motor module, a hydraulic module, a mechanical transmission module, and an electro-hydraulic composite wire-controlled steering control module;

[0009] The steering wheel module includes: a steering wheel, a first steering column, a steering wheel angle sensor, and a steering wheel torque sensor;

[0010] The steering wheel is fixedly connected to the first steering column;

[0011] The steering wheel angle sensor and the steering wheel torque sensor are both fixedly connected to the first steering column, respectively collecting the steering wheel angle and torque, and sending the collected steering wheel angle signal and steering wheel torque signal to the electro-hydraulic composite wire-controlled steering control module and the collaborative domain control module;

[0012] The steering motor module includes: a steering actuator motor, a first reduction mechanism, and a second steering column; the steering actuator motor transmits the electric power to the second steering column through the first reduction mechanism to provide power for the steering system;

[0013] The hydraulic module includes: a hydraulic pump, a hydraulic pump drive motor, a second reduction mechanism, an oil tank, a servo proportional solenoid valve, an oil pipe, a first pressure sensor, and a second pressure sensor. The hydraulic pump drive motor is connected to the hydraulic pump via the second reduction mechanism, and pumps hydraulic oil from the oil tank into the recirculating ball steering gear of the mechanical transmission module through the servo proportional solenoid valve, thereby forming an oil pressure differential in the recirculating ball steering gear, which provides power assistance to the steering system. The first pressure sensor and the second pressure sensor are installed on the oil pipes of the inlet and outlet oil circuits of the recirculating ball steering gear, and are used to detect the hydraulic power assistance on both sides of the recirculating ball steering gear and send a hydraulic power assistance signal.

[0014] The mechanical transmission module includes: a recirculating ball steering gear, a steering rocker arm, a steering straight tie rod, a left steering knuckle, a left steering knuckle arm, a left steering trapezoidal arm, a steering tie rod, a right steering trapezoidal arm, a right steering knuckle arm, and a right steering knuckle;

[0015] The recirculating ball steering gear is composed of a two-stage transmission pair: the first stage is a screw and nut transmission pair; the second stage is a rack and gear sector transmission pair; the second steering column is connected to the recirculating ball steering gear via the screw and nut transmission pair; the output end of the recirculating ball steering gear is connected to one end of the steering rocker arm via the rack and gear sector transmission pair, the other end of the steering rocker arm is connected to the left steering knuckle arm via a steering straight tie rod, driving the left steering knuckle and left front wheel to deflect; the left steering knuckle arm is connected to one end of the steering tie rod via the left steering trapezoidal arm; the other end of the steering tie rod is connected to the right trapezoidal arm, the right steering trapezoidal arm is connected to the right steering knuckle via the right steering knuckle arm, and the right steering knuckle drives the right front wheel to steer;

[0016] The electro-hydraulic composite wire-controlled steering control module is electrically connected to the steering wheel angle sensor, the steering wheel torque sensor, the steering motor module and the hydraulic module, respectively, and is used to receive the additional front wheel angle signal from the collaborative domain control module and send the additional front wheel angle signal to the steering motor module and the hydraulic module for collaborative control of the front wheel steering;

[0017] The electric composite brake-by-wire subsystem includes: a brake pedal, a brake pedal position sensor, a motor regenerative brake module, a pneumatic brake module and an electric composite brake-by-wire control module;

[0018] The motor regenerative braking module includes: a left front wheel brake motor, a left front wheel brake motor speed sensor, a left front wheel reduction mechanism, a left front wheel ball screw, a left front wheel brake cylinder, a right front wheel brake motor, a right front wheel brake motor speed sensor, a right front wheel reduction mechanism, a right front wheel ball screw, a right front wheel brake cylinder, a left rear wheel brake motor, a left rear wheel brake motor speed sensor, a left rear wheel reduction mechanism, a left rear wheel ball screw, a left rear wheel brake cylinder, a right rear wheel brake motor, a right rear wheel brake motor speed sensor, a right rear wheel reduction mechanism, a right rear wheel ball screw, and a right rear wheel brake cylinder;

[0019] The brake pedal position sensor is fixedly installed on the brake pedal and is used to send a brake pedal position signal to the electrical composite wire control brake control module; the output end of the left front wheel brake motor is connected to one end of the left front wheel ball screw through the left front wheel brake motor speed sensor and the left front wheel reduction mechanism in sequence, and the other end of the left front wheel ball screw is connected to the left front wheel brake cylinder; the output end of the right front wheel brake motor is connected to one end of the right front wheel ball screw through the right front wheel brake motor speed sensor and the right front wheel reduction mechanism in sequence, and the other end of the right front wheel ball screw is connected to the right front wheel brake cylinder; the output end of the left rear wheel brake motor is connected to one end of the left rear wheel ball screw through the left rear wheel brake motor speed sensor and the left rear wheel reduction mechanism in sequence, and the other end of the left rear wheel ball screw is connected to the left rear wheel brake cylinder; the output end of the right rear wheel brake motor is connected to one end of the left rear wheel ball screw through the left rear wheel brake motor speed sensor and the left rear wheel reduction mechanism in sequence, and the other end of the left rear wheel ball screw is connected to the left rear wheel brake cylinder; The right rear wheel brake motor speed sensor and the right rear wheel reduction mechanism are connected to one end of the right rear wheel ball screw, and the other end of the right rear wheel ball screw is connected to the right rear wheel brake cylinder; the rotational motion of the left front wheel brake motor, the right front wheel brake motor, the left rear wheel brake motor and the right rear wheel brake motor is respectively converted into displacement motion of the screw end of the left front wheel ball screw, the screw end of the right front wheel ball screw, the screw end of the left rear wheel ball screw and the screw end of the right rear wheel ball screw through the left front wheel reduction mechanism and the left front wheel ball screw, the right front wheel reduction mechanism and the right front wheel ball screw, the left rear wheel reduction mechanism and the left rear wheel ball screw, and the right rear wheel reduction mechanism and the right rear wheel ball screw, respectively acting on the left front wheel brake cylinder, the right front wheel brake cylinder, the left rear wheel brake cylinder and the right rear wheel brake cylinder to generate braking torque, thereby completing the braking operation of the vehicle;

[0020] The pneumatic brake module includes: an air compressor, an air reservoir, and a brake valve;

[0021] The air compressor compresses air into the air reservoir, and then inflates the left front wheel brake cylinder, the right front wheel brake cylinder, the left rear wheel brake cylinder, and the right rear wheel brake cylinder through the brake valve to achieve braking;

[0022] The electric composite wire control brake control module is electrically connected to the brake pedal position sensor, the left front wheel speed sensor, the right front wheel speed sensor, the left rear wheel speed sensor, the right rear wheel speed sensor, the vehicle speed sensor, the motor regenerative braking module, and the pneumatic brake module, respectively, and is used to receive the additional yaw torque signal from the collaborative domain control module and adjust the braking force of the motor regenerative braking force module and the pneumatic brake module according to the torque distribution strategy of the electric composite wire control brake subsystem;

[0023] The yaw rate sensor is used to obtain a vehicle yaw rate signal and send it to the collaborative domain control module;

[0024] The vehicle speed sensor is installed in any wheel and is used to obtain a vehicle speed signal and send it to the collaborative domain control module;

[0025] The collaborative domain control module calculates the additional yaw torque that the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem need to provide respectively, and sends the additional yaw torque signal and the additional front wheel angle signal to the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module, and collaboratively controls the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem to provide the additional yaw torque and the additional front wheel angle.

[0026] A collaborative control method for a multi-source coupled skateboard chassis system of the present invention, based on the above system, includes the following steps:

[0027] (1) Establish a four-degree-of-freedom model of a multi-source coupled skateboard chassis system;

[0028] (2) Based on the four-degree-of-freedom model of the multi-source coupled skateboard chassis system established in step (1), a polyhedron model of the skateboard chassis control is established using a polyhedron uncertainty method, and reference values ​​of the vehicle yaw rate and ideal center of mass sideslip angle are calculated;

[0029] (3) Design a collaborative domain control strategy for the multi-source coupled skateboard chassis system: design a state feedback control rate, then design a comprehensive stability factor based on the current state of the vehicle, and calculate the additional yaw torque that the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem need to provide based on the current comprehensive stability factor and the polyhedron model in step (2). The collaborative domain control module controls the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem to provide additional yaw torque and additional front wheel angle, thereby jointly improving vehicle stability;

[0030] (4) allocating the additional yaw torque required to be provided by the electric composite wire-controlled brake subsystem calculated in step (3) to the motor regenerative braking and pneumatic brake modules through the torque distribution strategy of the electric composite wire-controlled brake subsystem to provide the required braking force;

[0031] (5) Based on the additional yaw torque that the electro-hydraulic composite wire-controlled steering subsystem needs to provide calculated in step (3), the additional front wheel steering angle that the electro-hydraulic composite wire-controlled steering subsystem needs to provide is calculated, and the steering motor module and the hydraulic module are controlled by the electro-hydraulic composite wire-controlled steering control module to provide the additional front wheel steering angle.

[0032] Furthermore, the four-degree-of-freedom model of the multi-source coupled skateboard chassis system in step (1) is specifically as follows:

[0033]

[0034] Where m represents the mass of the vehicle; x and y represent the lateral and longitudinal displacements of the vehicle in the local coordinate system, respectively. The first-order differentials and second-order differentials of the two represent the lateral and longitudinal velocities and accelerations in the local coordinate system, respectively. represents the yaw angle, ω r is the vehicle yaw angular velocity, Represents the vehicle's yaw angular acceleration; m s Indicates the vehicle spring mass; F Xij , F Yij I represents the longitudinal tire force and lateral tire force of wheel ij respectively (ij=11 represents the left front wheel; ij=12 represents the right front wheel; ij=21 represents the left rear wheel; ij=22 represents the right rear wheel); I z Represents the vehicle's moment of inertia around the Z axis; I x represents the moment of inertia of the vehicle around the X axis; h c represents the height of the vehicle's center of mass; e represents the distance from the vehicle's roll center to the center of mass; φ represents the roll angle; C φ Indicates the roll coefficient; K φ Indicates the roll stiffness; C d Indicates the drag coefficient; A f represents the area in front of the vehicle; ρ represents the air density; l represents the wheelbase; a and b represent the distances from the front and rear axles to the center of mass, respectively; I xeq represents the equivalent moment of inertia of the sprung mass around the X axis; d represents the wheelbase; μ represents the road friction coefficient, δ f Indicates the front wheel turning angle;

[0035] The dynamic vertical load of the vehicle is modeled as:

[0036]

[0037] Where, F Zij represents the dynamic vertical load of wheel ij; g is the gravity proportional coefficient.

[0038] Furthermore, the step (2) is specifically as follows:

[0039] (21) Based on the four-degree-of-freedom model of the multi-source coupled skateboard chassis system established in step (1), a polyhedron model of the skateboard chassis control is established using the polyhedron uncertainty method as follows:

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] Among them, x is the state vector, x v is the sub-state vector, ΔM is the additional yaw moment, δ f is the front wheel angle, r is the state reference value, β n 、ω rn are the reference values ​​of the center of mass sideslip angle and yaw rate respectively; m is the vehicle mass, k1 and k2 are the cornering stiffness of the front and rear tires respectively, l f 、l r is the distance from the center of mass to the front and rear axles, u is the vehicle speed, ω r is the vehicle yaw rate, β is the vehicle's center of mass sideslip angle, I z is the moment of inertia of the vehicle around the z-axis; l is the vehicle wheelbase, K is the stability coefficient, and R is the specific matrix;

[0046] (22) The front wheel cornering stiffness, rear wheel cornering stiffness, and vehicle speed are defined as uncertainty parameters and expressed as:

[0047]

[0048] Where, F Yf is the front tire cornering force, F Yr is the rear tire cornering force, is the nominal value of the front tire cornering stiffness, is the nominal value of the rear tire cornering stiffness, α f is the front wheel slip angle, α r is the rear wheel slip angle, Δ1 and Δ2 are the uncertainties of the front and rear wheel cornering stiffness, is the nominal value of the vehicle speed, and Δ3 is the uncertainty of the vehicle speed.

[0049] Furthermore, the collaborative domain control strategy for the multi-source coupled skateboard chassis system in step (3) is specifically as follows:

[0050] (31) Design the state feedback control law for the multi-source coupled skateboard chassis system:

[0051]

[0052] Among them, K v is the overall control gain of the multi-source coupled skateboard chassis system; ρ j is the weight of the j-th vertex, K j is the control gain of the j-th vertex;

[0053] (32) Design comprehensive stability factor η:

[0054]

[0055] Among them, ay represents the vehicle lateral acceleration, β represents the vehicle sideslip angle, η is the comprehensive stability factor, λ1 and λ2 are the proportional factors of the vehicle lateral acceleration and the vehicle sideslip angle respectively;

[0056] (33) The additional yaw moment required to be provided by the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module is calculated as follows:

[0057] According to the comprehensive stability factor designed in step (32), the weights of the yaw torque provided by the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module when designing different comprehensive stability factors are:

[0058]

[0059]

[0060] Among them, η1, η2, η3, η4 are calibration thresholds, q sr Provides torque weight for the electro-hydraulic hybrid wire-controlled steering subsystem, q bk The weight of the torque provided to the electric composite wire control brake subsystem, the additional yaw torque provided by the electro-hydraulic composite steering is ΔM sr , the additional yaw moment provided by the electric compound brake is ΔM bk .

[0061] Furthermore, the torque distribution strategy of the electric composite wire controlled brake subsystem in step (4) is specifically as follows:

[0062] T ap =K1K1(s)ΔM bk / (1-K1(s)G(s) valve )

[0063] T m =[K2-K3(T m +T ap )]ΔM bk K2(s)G(s) motor / [1-K2(s)G(s) motor ]

[0064] Where: T m is the motor regenerative braking force; T ap is the air pressure force; K1 is the air pressure force distribution ratio; K2 is the motor regenerative braking force distribution ratio; K3 is the compound braking force feedback ratio; G(s) motor is the motor transfer function; G(s) valve is the brake valve transfer function; K1(s) is the robust controller of the motor regenerative braking force; K2(s) is the robust controller of the air pressure braking force.

[0065] Furthermore, the motor regenerative braking force robust controller and the air pressure braking force robust controller are both H ∞ Robust controller.

[0066] Furthermore, the step (5) is specifically as follows:

[0067] The additional yaw torque provided by the electro-hydraulic hybrid steer-by-wire subsystem is as follows:

[0068]

[0069] Calculate the additional front wheel steering angle that the electro-hydraulic hybrid steer-by-wire subsystem needs to provide:

[0070] Δδ sr =δ sr -δ f

[0071] Where Δδ sr The additional front wheel steering angle required by the electro-hydraulic composite wire-controlled steering subsystem, δ sr is the total front wheel turning angle δ required by the electro-hydraulic hybrid steer-by-wire subsystem f is the front wheel turning angle.

[0072] Beneficial effects of the present invention:

[0073] 1. This invention innovatively integrates all-wheel drive, steering, braking and other systems into a skateboard chassis system, enabling the independent development of the upper body and lower chassis, greatly enhancing the convenience of vehicle manufacturing, reducing manufacturing costs and shortening the R&D cycle.

[0074] 2. The present invention performs coordinated control on the skateboard chassis system, solving the control coupling and mutual interference of the chassis subsystems, while taking into account vehicle uncertainty and time-varying parameters, and can maximize the effectiveness of vehicle dynamic stability control.

[0075] 3. The multi-source coupling skateboard chassis system proposed in the present invention can be applied to various vehicle models, such as commercial vehicles, passenger vehicles, etc., and has high market value and practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 This is a schematic diagram of the structure of the multi-source coupling skateboard chassis system of the present invention;

[0077] Figure 2 This is a collaborative control flow chart of the multi-source coupled skateboard chassis system of the present invention;

[0078] Figure 3a A comparison chart of the path tracking effects of the collaborative control method of the present invention and single steering control, single braking control, and no control under harsh double lane change conditions;

[0079] Figure 3b A comparison diagram of the yaw rate tracking effect of the collaborative control method of the present invention and single steering control, single braking control, and no control under severe double lane change conditions;

[0080] In the figure, 1-steering wheel, 2-steering wheel angle sensor, 3-steering wheel torque sensor, 4-first steering column, 5-clutch, 6-left front wheel brake motor, 7-left front wheel brake motor speed sensor, 8-left front wheel speed sensor, 9-left front wheel hub motor, 10-left front wheel brake cylinder, 11-left front wheel reduction mechanism, 12-left front wheel ball screw, 13-left front wheel, 14-left rear wheel brake motor, 15-left rear wheel brake motor speed sensor, 16-left rear wheel speed sensor, 17-left rear wheel hub motor, 18- Left rear wheel brake cylinder, 19-left rear wheel reduction mechanism, 20-left rear wheel ball screw, 21-left rear wheel, 22-electro-hydraulic composite wire-controlled steering control module, 23-electrical composite wire-controlled brake control module, 24-right rear wheel, 25-right rear wheel ball screw, 26-right rear wheel reduction mechanism, 27-right rear wheel brake cylinder, 28-right rear wheel hub motor, 29-right rear wheel speed sensor, 30-right rear wheel brake motor speed sensor, 31-right rear wheel brake motor, 32-right front wheel, 33-right front wheel ball screw, 34-right front wheel reduction mechanism, 35-right front wheel brake cylinder, 36-right front wheel hub motor, 37-right front wheel speed sensor, 38-right front wheel brake motor speed sensor, 39-right front wheel brake motor, 40-second steering column, 41-screw and nut transmission pair, 42-rack and gear fan transmission pair, 43 - Recirculating ball hydraulic power steering gear, 44 - Steering rocker arm, 45 - Second reduction gear, 46 - Left steering knuckle, 47 - Left steering knuckle arm, 48 - Left steering trapezoidal arm, 49 - Steering straight tie rod, 50 - Steering actuator motor, 51 - First reduction gear, 52 - Hydraulic power assist module, 53 - Servo proportional solenoid valve, 54 - Steering tie rod, 55 - Right steering trapezoidal arm, 56 - Right steering knuckle arm, 57 - Right steering knuckle, 58 - Collaborative domain control module, 59 - Fuel tank, 60 - Hydraulic pump drive motor, 61 - Hydraulic pump, 62 - Drive-by-wire control module, 63 - First pressure sensor, 64 - Second pressure sensor, 65 - Brake pedal position sensor, 66 - Brake pedal, 67 - Accelerator pedal, 68 - Accelerator pedal position sensor, 69 - Brake valve, 70 - Air reservoir, 71 - Air compressor, 72 - Air pressure line;

[0081] A-steering wheel angle signal, B-steering wheel torque signal, C-hydraulic power assist signal, D-brake pedal position signal, E-accelerator pedal position signal, N-vehicle speed signal, P-yaw angular velocity signal. DETAILED DESCRIPTION

[0082] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and drawings. The contents mentioned in the embodiments are not intended to limit the present invention.

[0083] Reference Figure 1 As shown, a multi-source coupled skateboard chassis system of the present invention includes: a wire-controlled drive subsystem, an electro-hydraulic composite wire-controlled steering subsystem, an electric composite wire-controlled brake subsystem and a collaborative domain control module; wherein,

[0084] The drive-by-wire subsystem includes: an accelerator pedal 67, an accelerator pedal position sensor 68, a left front wheel hub motor 9, a right front wheel hub motor 36, a left rear wheel hub motor 17, a right rear wheel hub motor 28, a left front wheel speed sensor 8, a right front wheel speed sensor 37, a left rear wheel speed sensor 16, a right rear wheel speed sensor 29, a left front wheel 13, a right front wheel 32, a left rear wheel 21, a right rear wheel 24, and a drive-by-wire control module 62; the accelerator pedal position sensor 68 is fixedly mounted on the accelerator pedal 67 for sending an accelerator pedal position signal E to the drive-by-wire control module; the left front wheel hub motor 9 and the left front wheel speed sensor 8 are mounted in the left front wheel 13; the right front wheel hub motor 36 and the right front wheel speed sensor 37 are mounted in the right front wheel 32; the left rear wheel hub motor 17 and the left rear wheel speed sensor 16 are installed in the left rear wheel 21; the right rear wheel hub motor 28 and the right rear wheel speed sensor 29 are installed in the right rear wheel 24; the rotational motion output by the left front wheel hub motor 9, the right front wheel hub motor 36, the left rear wheel hub motor 17, and the right rear wheel hub motor 28 are respectively converted into the rotational motion of the left front wheel 13, the right front wheel 32, the left rear wheel 21, and the right rear wheel 24 to drive the vehicle; the input end of the wire-controlled drive control module 62 is connected to the left front wheel speed sensor 8, the right front wheel speed sensor 37, the left rear wheel speed sensor 16, and the right rear wheel speed sensor 29 through the on-board communication line, and the output end of the wire-controlled drive control module 62 is connected to the collaborative domain control module;

[0085] The electro-hydraulic composite wire-controlled steering subsystem includes: a steering wheel module, a steering motor module, a hydraulic module, a mechanical transmission module, and an electro-hydraulic composite wire-controlled steering control module;

[0086] The steering wheel module includes: a steering wheel 1, a first steering column 4, a steering wheel angle sensor 2, and a steering wheel torque sensor 3;

[0087] The steering wheel 1 is fixedly connected to the first steering column 4;

[0088] The steering wheel angle sensor 2 and the steering wheel torque sensor 3 are both fixedly connected to the first steering column 4, respectively collecting the steering wheel angle and torque of the steering wheel 1, and sending the collected steering wheel angle signal A and steering wheel torque signal B to the electro-hydraulic composite wire-controlled steering control module 22 and the collaborative domain control module;

[0089] The steering motor module includes: a steering actuator motor 50, a first reduction mechanism 51, and a second steering column 40; the steering actuator motor transmits the electric power to the second steering column 40 through the first reduction mechanism 51 to provide power for the steering system;

[0090] The hydraulic module includes: a hydraulic pump 61, a hydraulic pump drive motor 60, a second reduction mechanism 45, an oil tank 59, a servo proportional solenoid valve 53, an oil pipe, a first pressure sensor 63, and a second pressure sensor 64. The hydraulic pump drive motor 60 is connected to the hydraulic pump 61 via the second reduction mechanism 45, and pumps hydraulic oil from the oil tank 59 into the recirculating ball steering gear of the mechanical transmission module through the servo proportional solenoid valve 53, thereby forming an oil pressure differential in the recirculating ball steering gear, which provides power assistance to the steering system. The first pressure sensor 63 and the second pressure sensor 64 are installed on the oil pipes of the recirculating ball steering gear's inlet and outlet oil circuits, and are used to detect the hydraulic power assistance on both sides of the recirculating ball steering gear and send a hydraulic power assistance signal C.

[0091] The mechanical transmission module includes: a recirculating ball steering gear, a steering rocker arm 44, a steering straight tie rod 49, a left steering knuckle 46, a left steering knuckle arm 47, a left steering trapezoidal arm 48, a steering tie rod 54, a right steering trapezoidal arm 55, a right steering knuckle arm 56, and a right steering knuckle 57;

[0092] The recirculating ball steering gear is composed of a two-stage transmission pair: the first stage is a screw and nut transmission pair 41; the second stage is a rack and gear sector transmission pair 42; the second steering column 40 is connected to the recirculating ball steering gear via the screw and nut transmission pair 41; the output end of the recirculating ball steering gear is connected to one end of a steering rocker arm 44 via the rack and gear sector transmission pair 42, and the other end of the steering rocker arm 44 is connected to the left steering knuckle arm 47 via a steering straight tie rod 49, driving the left steering knuckle 46 and the left front wheel 13 to deflect; the left steering knuckle arm 47 is connected to one end of a steering tie rod 54 via a left steering trapezoidal arm 48; the other end of the steering tie rod 54 is connected to a right steering trapezoidal arm 55, and the right steering trapezoidal arm 55 is connected to a right steering knuckle 57 via a right steering knuckle arm 56, and the right steering knuckle 57 drives the right front wheel 32 to steer;

[0093] The electro-hydraulic composite wire-controlled steering control module 22 is electrically connected to the steering wheel angle sensor 2, the steering wheel torque sensor 3, the steering motor module and the hydraulic module, respectively, and is used to receive the additional front wheel angle signal from the collaborative domain control module and send the additional front wheel angle signal to the steering motor module and the hydraulic module for collaborative control of the front wheel steering;

[0094] The electric composite brake-by-wire subsystem includes: a brake pedal 66, a brake pedal position sensor 65, a motor regenerative brake module, a pneumatic brake module and an electric composite brake-by-wire control module 23;

[0095] The motor regenerative braking module includes: a left front wheel brake motor 6, a left front wheel brake motor speed sensor 7, a left front wheel deceleration mechanism 11, a left front wheel ball screw 12, a left front wheel brake cylinder 10, a right front wheel brake motor 39, a right front wheel brake motor speed sensor 38, a right front wheel deceleration mechanism 34, a right front wheel ball screw 33, a right front wheel brake cylinder 35, a left rear wheel brake motor 14, a left rear wheel brake motor speed sensor 15, a left rear wheel deceleration mechanism 19, a left rear wheel ball screw 20, a left rear wheel brake cylinder 18, a right rear wheel brake motor 31, a right rear wheel brake motor speed sensor 30, a right rear wheel deceleration mechanism 26, a right rear wheel ball screw 25, and a right rear wheel brake cylinder 27;

[0096] The brake pedal position sensor 65 is fixedly mounted on the brake pedal 66 and is used to send a brake pedal position signal D to the electric composite wire control brake control module; the output end of the left front wheel brake motor 6 is connected to one end of the left front wheel ball screw 12 through the left front wheel brake motor speed sensor 7 and the left front wheel reduction mechanism 11, and the other end of the left front wheel ball screw 12 is connected to the left front wheel brake cylinder 10; the output end of the right front wheel brake motor 39 is connected to one end of the right front wheel ball screw 33 through the right front wheel brake motor speed sensor 38 and the right front wheel reduction mechanism 34, and the other end of the right front wheel ball screw is connected to the right front wheel brake cylinder 35; the output end of the left rear wheel brake motor 14 is connected to one end of the left rear wheel ball screw 20 through the left rear wheel brake motor speed sensor 15 and the left rear wheel reduction mechanism 19, and the other end of the left rear wheel ball screw 20 is connected to the left rear wheel brake cylinder 18; the output end of the right rear wheel brake motor 31 is connected to the right rear wheel brake motor speed sensor 30 and the right rear wheel reduction mechanism 26 in sequence. The left front wheel brake motor 6, the right front wheel brake motor 39, the left rear wheel brake motor 14, and the right rear wheel brake motor 31 rotate in sequence through the left front wheel reduction mechanism 11 and the left front wheel ball screw 12, the right front wheel reduction mechanism 34 and the right front wheel ball screw 33, the left rear wheel reduction mechanism 19 and the left rear wheel ball screw 20. The right rear wheel reduction mechanism 26 and the right rear wheel ball screw 25 convert the displacement motion into the screw rod ends of the left front wheel ball screw 12, the screw rod ends of the right front wheel ball screw 33, the screw rod ends of the left rear wheel ball screw 20, and the screw rod ends of the right rear wheel ball screw 25, which respectively act on the left front wheel brake cylinder 10, the right front wheel brake cylinder 35, the left rear wheel brake cylinder 18, and the right rear wheel brake cylinder 27 to generate braking torque, completing the vehicle braking operation;

[0097] The pneumatic brake module includes: an air compressor 71, an air reservoir 70, and a brake valve 69;

[0098] The air compressor 71 compresses air into the air reservoir 70, and then inflates the left front wheel brake cylinder 10, the right front wheel brake cylinder 35, the left rear wheel brake cylinder 18, and the right rear wheel brake cylinder 27 through the brake valve 69 to achieve braking;

[0099] The electric composite wire-controlled brake control module 23 is electrically connected to the brake pedal position sensor 65, the left front wheel speed sensor 8, the right front wheel speed sensor 37, the left rear wheel speed sensor 16, the right rear wheel speed sensor 29, the vehicle speed sensor, the motor regenerative braking module, and the pneumatic brake module, respectively, and is used to receive the additional yaw torque signal from the collaborative domain control module and adjust the braking force of the motor regenerative braking force module and the pneumatic brake module according to the torque distribution strategy of the electric composite wire-controlled brake subsystem;

[0100] The yaw rate sensor is used to obtain a vehicle yaw rate signal P and send it to the cooperative domain control module;

[0101] The vehicle speed sensor is installed in any wheel, and is used to obtain a vehicle speed signal N and send it to the collaborative domain control module;

[0102] The collaborative domain control module calculates the additional yaw torque that the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem need to provide respectively, and sends the additional yaw torque signal and the additional front wheel angle signal to the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module 23, and collaboratively controls the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem to provide the additional yaw torque and the additional front wheel angle.

[0103] Reference Figure 2 As shown, a collaborative control method of a multi-source coupled skateboard chassis system of the present invention, based on the above system, includes the following steps:

[0104] (1) Establish a four-degree-of-freedom model of a multi-source coupled skateboard chassis system;

[0105] The four-degree-of-freedom model of the multi-source coupled skateboard chassis system is as follows:

[0106]

[0107] Where m represents the mass of the vehicle; x and y represent the lateral and longitudinal displacements of the vehicle in the local coordinate system, respectively. The first-order differentials and second-order differentials of the two represent the lateral and longitudinal velocities and accelerations in the local coordinate system, respectively. represents the yaw angle, ω r is the vehicle yaw angular velocity, Represents the vehicle's yaw angular acceleration; m s Indicates the vehicle spring mass; F Xij , F Yij I represents the longitudinal tire force and lateral tire force of wheel ij respectively (ij=11 represents the left front wheel; ij=12 represents the right front wheel; ij=21 represents the left rear wheel; ij=22 represents the right rear wheel); I z Represents the vehicle's moment of inertia around the Z axis; I x represents the moment of inertia of the vehicle around the X axis; h c represents the height of the vehicle's center of mass; e represents the distance from the vehicle's roll center to the center of mass; φ represents the roll angle; C φ Indicates the roll coefficient; K φ Indicates the roll stiffness; C d Indicates the drag coefficient; A frepresents the area in front of the vehicle; ρ represents the air density; l represents the wheelbase; a and b represent the distances from the front and rear axles to the center of mass, respectively; I xeq represents the equivalent moment of inertia of the sprung mass around the X axis; d represents the wheelbase; μ represents the road friction coefficient, δ f Indicates the front wheel turning angle;

[0108] The dynamic vertical load of the vehicle is modeled as:

[0109]

[0110] Where, F Zij represents the dynamic vertical load of wheel ij; g is the gravity proportional coefficient.

[0111] (2) Based on the four-degree-of-freedom model of the multi-source coupled skateboard chassis system established in step (1), a polyhedron model of the skateboard chassis control is established using a polyhedron uncertainty method, and reference values ​​of the vehicle yaw rate and ideal center of mass sideslip angle are calculated; specifically, as follows:

[0112] (21) Based on the four-degree-of-freedom model of the multi-source coupled skateboard chassis system established in step (1), a polyhedron model of the skateboard chassis control is established using the polyhedron uncertainty method as follows:

[0113]

[0114]

[0115]

[0116]

[0117]

[0118] Among them, x is the state vector, x v is the sub-state vector, ΔM is the additional yaw moment, δ f is the front wheel angle, r is the state reference value, β n 、ω rn are the reference values ​​of the center of mass sideslip angle and yaw rate respectively; m is the vehicle mass, k1 and k2 are the cornering stiffness of the front and rear tires respectively, l f 、l r is the distance from the center of mass to the front and rear axles, u is the vehicle speed, ω r is the vehicle yaw rate, β is the vehicle's center of mass sideslip angle, I z is the moment of inertia of the vehicle around the z-axis; l is the vehicle wheelbase, K is the stability coefficient, and R is the specific matrix;

[0119] (22) The front wheel cornering stiffness, rear wheel cornering stiffness, and vehicle speed are defined as uncertainty parameters and expressed as:

[0120]

[0121] Where, F Yf is the front tire cornering force, F Yr is the rear tire cornering force, is the nominal value of the front tire cornering stiffness, is the nominal value of the rear tire cornering stiffness, α f is the front wheel slip angle, α r is the rear wheel slip angle, Δ1 and Δ2 are the uncertainties of the front and rear wheel cornering stiffness, is the nominal value of the vehicle speed, and Δ3 is the uncertainty of the vehicle speed.

[0122] (3) Design a collaborative domain control strategy for the multi-source coupled skateboard chassis system: design a state feedback control rate, then design a comprehensive stability factor based on the current state of the vehicle, and calculate the additional yaw torque that the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem need to provide based on the current comprehensive stability factor and the polyhedron model in step (2). The collaborative domain control module controls the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem to provide additional yaw torque and additional front wheel angle, thereby jointly improving vehicle stability;

[0123] The collaborative domain control strategy of the multi-source coupled skateboard chassis system is specifically designed as follows:

[0124] (31) Design the state feedback control law for the multi-source coupled skateboard chassis system:

[0125]

[0126] Among them, K v is the overall control gain of the multi-source coupled skateboard chassis system; ρ j is the weight of the j-th vertex, K j is the control gain of the j-th vertex;

[0127] (32) Design comprehensive stability factor η:

[0128]

[0129] Among them, a y represents the vehicle lateral acceleration, β represents the vehicle sideslip angle, η is the comprehensive stability factor, λ1 and λ2 are the proportional factors of the vehicle lateral acceleration and the vehicle sideslip angle respectively;

[0130] (33) The additional yaw moment required to be provided by the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module is calculated as follows:

[0131] According to the comprehensive stability factor designed in step (32), the weights of the yaw torque provided by the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module when designing different comprehensive stability factors are:

[0132]

[0133]

[0134] Among them, η1, η2, η3, η4 are calibration thresholds, q sr Provides torque weight for the electro-hydraulic hybrid wire-controlled steering subsystem, q bk The weight of the torque provided to the electric composite wire control brake subsystem, the additional yaw torque provided by the electro-hydraulic composite steering is ΔM sr , the additional yaw moment provided by the electric compound brake is ΔM bk .

[0135] (4) allocating the additional yaw torque required to be provided by the electric composite wire-controlled brake subsystem calculated in step (3) to the motor regenerative braking and pneumatic brake modules through the torque distribution strategy of the electric composite wire-controlled brake subsystem to provide the required braking force;

[0136] The torque distribution strategy of the electric composite wire-controlled brake subsystem is as follows:

[0137] T ap =K1K1(s)ΔM bk / (1-K1(s)G(s) valve )

[0138] T m =[K2-K3(T m +T ap )]ΔM bk K2(s)G(s) motor / [1-K2(s)G(s) motor ]

[0139] Where: T m is the motor regenerative braking force; T ap is the air pressure force; K1 is the air pressure force distribution ratio; K2 is the motor regenerative braking force distribution ratio; K3 is the compound braking force feedback ratio; G(s) motor is the motor transfer function; G(s) valve is the brake valve transfer function; K1(s) is the robust controller of the motor regenerative braking force; K2(s) is the robust controller of the air pressure braking force.

[0140] Furthermore, the motor regenerative braking force robust controller and the air pressure braking force robust controller are both H ∞ Robust controller.

[0141] (5) Based on the additional yaw torque that the electro-hydraulic composite wire-controlled steering subsystem needs to provide, calculated in step (3), the additional front wheel steering angle that the electro-hydraulic composite wire-controlled steering subsystem needs to provide is calculated, and the electro-hydraulic composite wire-controlled steering control module controls the steering motor module and the hydraulic module to provide the additional front wheel steering angle; specifically, as follows:

[0142] The additional yaw torque provided by the electro-hydraulic hybrid steer-by-wire subsystem is as follows:

[0143]

[0144] Calculate the additional front wheel steering angle that the electro-hydraulic hybrid steer-by-wire subsystem needs to provide:

[0145] Δδ sr =δ sr -δ f

[0146] Where Δδ sr The additional front wheel steering angle required by the electro-hydraulic composite wire-controlled steering subsystem, δ sr is the total front wheel turning angle δ required by the electro-hydraulic hybrid steer-by-wire subsystem f is the front wheel turning angle.

[0147] Under the severe double lane change condition, the vehicle speed is set between 85km / h and 95km / h. The test results are as follows: Figure 3a , as shown in Figure 3b;

[0148] like Figure 3a As shown in the figure, the vehicle's trajectory deviates without any control, indicating that under this condition the vehicle will slip and seriously deviate from the expected trajectory. The effects of single steering control, single braking control, and cooperative control can all track the target trajectory, but the cooperative control method can track the expected trajectory more accurately than any single control method. Therefore, the proposed cooperative control method has better vehicle stability performance. Figure 3b As shown in Figure 3, the effects of single steering control, single braking control, and cooperative control can all track the reference value of its yaw rate, but the control error under the proposed cooperative control method is smaller than that under any single control method.

[0149] The present invention has many specific application paths. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be considered as the scope of protection of the present invention.

Claims

1. A collaborative control method for a multi-source coupled skateboard chassis system, based on the multi-source coupled skateboard chassis system, comprising: Drive-by-wire subsystem, electro-hydraulic composite steering-by-wire subsystem, electrical composite brake-by-wire subsystem and collaborative domain control module; The electro-hydraulic composite wire-controlled steering subsystem includes: a steering wheel module, a steering motor module, a hydraulic module, a mechanical transmission module, and an electro-hydraulic composite wire-controlled steering control module; The steering wheel module includes: a steering wheel, a first steering column, a steering wheel angle sensor, and a steering wheel torque sensor; The steering wheel is fixedly connected to the first steering column; The steering wheel angle sensor and the steering wheel torque sensor are both fixedly connected to the first steering column, respectively collecting the steering wheel angle and torque, and sending the collected steering wheel angle signal and steering wheel torque signal to the electro-hydraulic composite wire-controlled steering control module and the collaborative domain control module; The steering motor module includes: a steering actuator motor, a first reduction mechanism, and a second steering column; the steering actuator motor transmits the electric power to the second steering column through the first reduction mechanism to provide power for the steering system; The hydraulic module includes: a hydraulic pump, a hydraulic pump drive motor, a second reduction mechanism, an oil tank, a servo proportional solenoid valve, an oil pipe, a first pressure sensor, and a second pressure sensor. The hydraulic pump drive motor is connected to the hydraulic pump via the second reduction mechanism, and pumps hydraulic oil from the oil tank into the recirculating ball steering gear of the mechanical transmission module through the servo proportional solenoid valve, thereby forming an oil pressure differential in the recirculating ball steering gear, which provides power assistance to the steering system. The first pressure sensor and the second pressure sensor are installed on the oil pipes of the inlet and outlet oil circuits of the recirculating ball steering gear, and are used to detect the hydraulic power assistance on both sides of the recirculating ball steering gear and send a hydraulic power assistance signal. The mechanical transmission module includes: a recirculating ball steering gear, a steering rocker arm, a steering straight tie rod, a left steering knuckle, a left steering knuckle arm, a left steering trapezoidal arm, a steering tie rod, a right steering trapezoidal arm, a right steering knuckle arm, and a right steering knuckle; The recirculating ball steering gear is composed of a two-stage transmission pair: the first stage is a screw and nut transmission pair; the second stage is a rack and gear sector transmission pair; the second steering column is connected to the recirculating ball steering gear via the screw and nut transmission pair; the output end of the recirculating ball steering gear is connected to one end of the steering rocker arm via the rack and gear sector transmission pair, the other end of the steering rocker arm is connected to the left steering knuckle arm via a steering straight tie rod, driving the left steering knuckle and left front wheel to deflect; the left steering knuckle arm is connected to one end of the steering tie rod via the left steering trapezoidal arm; the other end of the steering tie rod is connected to the right trapezoidal arm, the right steering trapezoidal arm is connected to the right steering knuckle via the right steering knuckle arm, and the right steering knuckle drives the right front wheel to steer; The electro-hydraulic composite wire-controlled steering control module is electrically connected to the steering wheel angle sensor, the steering wheel torque sensor, the steering motor module and the hydraulic module, respectively, and is used to receive the additional front wheel angle signal from the collaborative domain control module and send the additional front wheel angle signal to the steering motor module and the hydraulic module for collaborative control of the front wheel steering; The electric composite brake-by-wire subsystem includes: a brake pedal, a brake pedal position sensor, a motor regenerative brake module, a pneumatic brake module and an electric composite brake-by-wire control module; The motor regenerative braking module includes: a left front wheel brake motor, a left front wheel brake motor speed sensor, a left front wheel reduction mechanism, a left front wheel ball screw, a left front wheel brake cylinder, a right front wheel brake motor, a right front wheel brake motor speed sensor, a right front wheel reduction mechanism, a right front wheel ball screw, a right front wheel brake cylinder, a left rear wheel brake motor, a left rear wheel brake motor speed sensor, a left rear wheel reduction mechanism, a left rear wheel ball screw, a left rear wheel brake cylinder, a right rear wheel brake motor, a right rear wheel brake motor speed sensor, a right rear wheel reduction mechanism, a right rear wheel ball screw, and a right rear wheel brake cylinder; The brake pedal position sensor is fixedly installed on the brake pedal and is used to send a brake pedal position signal to the electrical composite wire control brake control module; the output end of the left front wheel brake motor is connected to one end of the left front wheel ball screw through the left front wheel brake motor speed sensor and the left front wheel reduction mechanism in sequence, and the other end of the left front wheel ball screw is connected to the left front wheel brake cylinder; the output end of the right front wheel brake motor is connected to one end of the right front wheel ball screw through the right front wheel brake motor speed sensor and the right front wheel reduction mechanism in sequence, and the other end of the right front wheel ball screw is connected to the right front wheel brake cylinder; the output end of the left rear wheel brake motor is connected to one end of the left rear wheel ball screw through the left rear wheel brake motor speed sensor and the left rear wheel reduction mechanism in sequence, and the other end of the left rear wheel ball screw is connected to the left rear wheel brake cylinder; the output end of the right rear wheel brake motor is connected to one end of the left rear wheel ball screw through the left rear wheel brake motor speed sensor and the left rear wheel reduction mechanism in sequence, and the other end of the left rear wheel ball screw is connected to the left rear wheel brake cylinder; The right rear wheel brake motor speed sensor and the right rear wheel reduction mechanism are connected to one end of the right rear wheel ball screw, and the other end of the right rear wheel ball screw is connected to the right rear wheel brake cylinder; the rotational motion of the left front wheel brake motor, the right front wheel brake motor, the left rear wheel brake motor and the right rear wheel brake motor is respectively converted into displacement motion of the screw end of the left front wheel ball screw, the screw end of the right front wheel ball screw, the screw end of the left rear wheel ball screw and the screw end of the right rear wheel ball screw through the left front wheel reduction mechanism and the left front wheel ball screw, the right front wheel reduction mechanism and the right front wheel ball screw, the left rear wheel reduction mechanism and the left rear wheel ball screw, and the right rear wheel reduction mechanism and the right rear wheel ball screw, respectively acting on the left front wheel brake cylinder, the right front wheel brake cylinder, the left rear wheel brake cylinder and the right rear wheel brake cylinder to generate braking torque, thereby completing the braking operation of the vehicle; The pneumatic brake module includes: an air compressor, an air reservoir, and a brake valve; The air compressor compresses air into the air reservoir, and then inflates the left front wheel brake cylinder, the right front wheel brake cylinder, the left rear wheel brake cylinder, and the right rear wheel brake cylinder through the brake valve to achieve braking; The electric composite wire control brake control module is electrically connected to the brake pedal position sensor, the left front wheel speed sensor, the right front wheel speed sensor, the left rear wheel speed sensor, the right rear wheel speed sensor, the vehicle speed sensor, the motor regenerative braking module, and the pneumatic brake module, respectively, and is used to receive the additional yaw torque signal from the collaborative domain control module and adjust the braking force of the motor regenerative braking force module and the pneumatic brake module according to the torque distribution strategy of the electric composite wire control brake subsystem; The method is characterized in that the method comprises the following steps: (1) Establish a four-degree-of-freedom model of a multi-source coupled skateboard chassis system; (2) Based on the four-degree-of-freedom model of the multi-source coupled skateboard chassis system established in step (1), a polyhedron model of the skateboard chassis control is established using a polyhedron uncertainty method, and reference values ​​of the vehicle yaw rate and ideal center of mass sideslip angle are calculated; (3) Designing a collaborative domain control strategy for a multi-source coupled skateboard chassis system: designing a state feedback control rate, and then designing a comprehensive stability factor according to the current state of the vehicle. Based on the current comprehensive stability factor and the polyhedron model in step (2), the additional yaw torque required to be provided by the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem is calculated respectively. The collaborative domain control module controls the electro-hydraulic composite wire-controlled steering subsystem and the electrical composite wire-controlled brake subsystem to provide the additional yaw torque and the additional front wheel turning angle. (4) allocating the additional yaw torque required to be provided by the electric composite wire-controlled brake subsystem calculated in step (3) to the motor regenerative braking and pneumatic brake modules through the torque distribution strategy of the electric composite wire-controlled brake subsystem to provide the required braking force; (5) Based on the additional yaw torque that the electro-hydraulic composite wire-controlled steering subsystem needs to provide calculated in step (3), the additional front wheel steering angle that the electro-hydraulic composite wire-controlled steering subsystem needs to provide is calculated, and the steering motor module and the hydraulic module are controlled by the electro-hydraulic composite wire-controlled steering control module to provide the additional front wheel steering angle.

2. The collaborative control method of a multi-source coupled skateboard chassis system according to claim 1, characterized in that: The four-degree-of-freedom model of the multi-source coupled skateboard chassis system in step (1) is specifically as follows: Where m represents the mass of the vehicle; x and y represent the lateral and longitudinal displacements of the vehicle in the local coordinate system, respectively. The first-order differentials and second-order differentials of the two represent the lateral and longitudinal velocities and accelerations in the local coordinate system, respectively. represents the yaw angle, ω r is the vehicle yaw angular velocity, Represents the vehicle's yaw angular acceleration; m s Indicates the vehicle spring mass; F Xij , F Yij They represent the longitudinal tire force and lateral tire force of wheel ij, ij=11 represents the left front wheel; ij=12 represents the right front wheel; ij=21 represents the left rear wheel; ij=22 represents the right rear wheel; I z Represents the vehicle's moment of inertia around the Z axis; I x represents the moment of inertia of the vehicle around the X axis; h c represents the height of the vehicle's center of mass; e represents the distance from the vehicle's roll center to the center of mass; φ represents the roll angle; C φ Indicates the roll coefficient; K φ Indicates the roll stiffness; C d Indicates the drag coefficient; A f represents the area in front of the vehicle; ρ represents the air density; l represents the wheelbase; a and b represent the distances from the front and rear axles to the center of mass, respectively; I xeq represents the equivalent moment of inertia of the sprung mass around the X axis; d represents the wheelbase; μ represents the road friction coefficient, δ f Indicates the front wheel turning angle; The dynamic vertical load of the vehicle is modeled as: Where, F Zij represents the dynamic vertical load of wheel ij; g is the gravity proportional coefficient.

3. The coordinated control method of a multi-source coupled skateboard chassis system according to claim 2, characterized in that: The step (2) is specifically as follows: (21) Based on the four-degree-of-freedom model of the multi-source coupled skateboard chassis system established in step (1), a polyhedron model of the skateboard chassis control is established using the polyhedron uncertainty method as follows: Among them, x is the state vector, x v is the sub-state vector, ΔM is the additional yaw moment, δ f is the front wheel angle, r is the state reference value, β n 、ω rn are the reference values ​​of the center of mass sideslip angle and yaw rate respectively; m is the vehicle mass, k1 and k2 are the cornering stiffness of the front and rear tires respectively, l f 、l r is the distance from the center of mass to the front and rear axles, u is the vehicle speed, ω r is the vehicle yaw rate, β is the vehicle's center of mass sideslip angle, I z is the moment of inertia of the vehicle around the z-axis; l is the vehicle wheelbase, K is the stability coefficient, and R is the specific matrix; (22) The front wheel cornering stiffness, rear wheel cornering stiffness, and vehicle speed are defined as uncertainty parameters and expressed as: Where, F Yf is the front tire cornering force, F Yr is the rear tire cornering force, is the nominal value of the front tire cornering stiffness, is the nominal value of the rear tire cornering stiffness, α f is the front wheel slip angle, α r is the rear wheel slip angle, Δ1 and Δ2 are the uncertainties of the front and rear wheel cornering stiffness, is the nominal value of the vehicle speed, and Δ3 is the uncertainty of the vehicle speed.

4. The coordinated control method of a multi-source coupled skateboard chassis system according to claim 3, characterized in that: The collaborative domain control strategy for the multi-source coupled skateboard chassis system in step (3) is specifically as follows: (31) Design the state feedback control law for the multi-source coupled skateboard chassis system: Among them, K v is the overall control gain of the multi-source coupled skateboard chassis system; ρ j is the weight of the j-th vertex, K j is the control gain of the j-th vertex; (32) Design comprehensive stability factor η: Among them, a y represents the vehicle lateral acceleration, β represents the vehicle sideslip angle, η is the comprehensive stability factor, λ1 and λ2 are the proportional factors of the vehicle lateral acceleration and the vehicle sideslip angle respectively; (33) The additional yaw moment required to be provided by the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module is calculated as follows: According to the comprehensive stability factor designed in step (32), the weights of the yaw torque provided by the electro-hydraulic composite wire-controlled steering control module and the electrical composite wire-controlled brake control module when designing different comprehensive stability factors are: Among them, η1, η2, η3, η4 are calibration thresholds, q sr Provides torque weight for the electro-hydraulic hybrid wire-controlled steering subsystem, q bk The weight of the torque provided to the electric composite wire control brake subsystem, the additional yaw torque provided by the electro-hydraulic composite steering is ΔM sr , the additional yaw moment provided by the electric compound brake is ΔM bk ; The torque distribution strategy of the electric composite wire controlled brake subsystem in step (4) is specifically as follows: T ap =K1K1(s)ΔM bk / (1-K1(s)G(s) valve ) T m =[K2-K3(T m +T ap )]ΔM bk K2(s)G(s) motor / [1-K2(s)G(s) motor ] Where: T m is the motor regenerative braking force; T ap is the air pressure force; K1 is the air pressure force distribution ratio; K2 is the motor regenerative braking force distribution ratio; K3 is the compound braking force feedback ratio; G(s) motor is the motor transfer function; G(s) valve is the brake valve transfer function; K1(s) is the robust controller of the motor regenerative braking force; K2(s) is the robust controller of the air pressure braking force.

5. The coordinated control method of a multi-source coupled skateboard chassis system according to claim 4, characterized in that: The motor regenerative braking force robust controller and the air pressure braking force robust controller are both H ∞ Robust controller.

6. The coordinated control method of a multi-source coupled skateboard chassis system according to claim 4, characterized in that: The step (5) is specifically as follows: The additional yaw torque provided by the electro-hydraulic hybrid steer-by-wire subsystem is as follows: Calculate the additional front wheel steering angle that the electro-hydraulic hybrid steer-by-wire subsystem needs to provide: Dd sr =d sr -d f Where Δδ sr The additional front wheel steering angle required by the electro-hydraulic composite wire-controlled steering subsystem, δ sr is the total front wheel turning angle δ required by the electro-hydraulic hybrid steer-by-wire subsystem f is the front wheel turning angle.

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