Hardware-in-the-loop simulation test bench for drive-by-wire chassis electric vehicle and power chassis domain integrated control architecture of hardware-in-the-loop simulation test bench

Abstract

The invention discloses a drive-by-wire chassis electric vehicle hardware-in-the-loop simulation test bench and a power chassis domain integrated control architecture thereof. The test bench comprises a driving simulation system, an electric drive system, a drive-by-wire brake system, a drive-by-wire steering system, an active suspension system, a power chassis domain integrated control system, a vehicle real-time simulation system and a bench measurement and control system. And the power chassis domain integrated control system receives a driver instruction, road environment and vehicle model information and response information of each execution system of the power chassis and the load simulation device of the execution system to complete decision-making instruction sending. The power chassis domain integrated control system adopts a hierarchical control architecture and comprises a vehicle motion stability judgment layer, a vehicle motion integrated control layer and an actuator and load control layer thereof. The system is used for testing and verifying control algorithms of various movement modes such as transverse and longitudinal movement modes, transverse and vertical movement modes and transverse, longitudinal and vertical movement modes of the drive-by-wire chassis intelligent electric vehicle, and has the characteristics of complete drive-by-wire chassis functions, high power chassis domain fusion degree, wide test coverage and the like.

Description

Technical Field

[0001] The present invention relates to the field of vehicle hardware-in-the-loop test benches, and in particular to a hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and an integrated control architecture for a power chassis domain thereof. Background Art

[0002] With the accelerated integration and development of the "new four modernizations" of automobile technologies, the research and development of intelligent driving functions of electric vehicles is also deepening. As the carrier and execution component of the realization of intelligent driving functions, the verification of the functions and control strategies of power transmission and chassis is crucial to ensure the safety, reliability and comfort of vehicles. At the same time, with the continuous evolution of automotive electronic and electrical architecture, the correlation between the functions of various subsystems in the chassis domain and between the chassis domain and the power domain is becoming stronger and stronger. The traditional single actuator test bench is difficult to meet the integration and verification of functional modules such as intelligent driving decision-making and control. In addition, in order to achieve intelligent driving, the operation of the vehicle has gradually shifted from the traditional manual driving mode to the human-machine co-driving mode or the automatic driving mode. Faced with driving instructions from different sources and different driving conditions, the traditional electric power steering system and electronic stability system cannot guarantee the optimal vehicle motion control due to the characteristics of independent control of the ECU. Therefore, the wire control steering, wire control braking and active suspension systems have been widely used in the chassis of intelligent electric vehicles due to their decoupling and rapid response characteristics. The chassis domain control technology can effectively integrate the functions of various subsystems; in addition, the precise and rapid response characteristics of the drive motor also make the integrated control of the chassis and power domain possible.

[0003] Patent No. CN113029597A discloses a fully controlled-by-wire chassis test system for unmanned vehicles. The system includes a chassis test execution system, a measurement and control system, and a human-computer interaction system, etc., which can realize the testing of multiple working conditions, multiple actuators, and multiple motion behaviors of the fully controlled-by-wire chassis of unmanned vehicles. However, the system does not consider the impact of the vertical motion of the vehicle on the dynamics of the vehicle system, so the test results will be quite different from the actual vehicle performance. Patent No. CN115452411B discloses a fully hardware-in-the-loop coordinated control method and application of the controlled-by-wire chassis of an intelligent networked vehicle. The method is applied to a system composed of a control module, an actuator module, and a vehicle module. The controller coordinates the coupled motion of each subsystem of the controlled-by-wire chassis of the intelligent networked vehicle through different vehicle working conditions, and applies the control method to the hardware-in-the-loop test bench, thereby improving the authenticity and reliability of the bench test results. However, this method only artificially divides the working boundaries of each subsystem actuator through the coordinator according to different working conditions, gives corresponding coordination control signals to the ECU of each subsystem of the wire-controlled chassis, and each actuator is controlled separately. It fails to achieve integrated control of each subsystem and cannot ensure the optimal control response of each actuator.

[0004] In summary, the current hardware-in-the-loop test benches and control methods for wire-controlled chassis vehicles mostly fail to consider the impact of the vehicle's vertical motion on the vehicle system dynamics, and most methods only achieve coordinated control of the vehicle's motion through the intervention of various actuator subsystems in the chassis domain in a time-sharing and working condition-based manner. There is a lack of consideration of the integrated control architecture of various actuator systems in the chassis domain or between the chassis and power domains, and the authenticity and reliability of the hardware-in-the-loop test results cannot be guaranteed, making it difficult to accurately simulate the actual motion effects of the vehicle. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to overcome the defects of the above-mentioned prior art, give full consideration to the coupling relationship of multiple actuators, ensure the authenticity and reliability of the hardware-in-the-loop test results of the vehicle motion control algorithm, and provide a hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture.

[0006] Technical solution: The hardware-in-the-loop simulation test bench for the electric vehicle with a controlled-by-wire chassis and its integrated control architecture for the power chassis domain include: driving simulation system, electric drive system, controlled-by-wire braking system, controlled-by-wire steering system, active suspension system, integrated control system for the power chassis domain, vehicle real-time simulation system, and test bench measurement and control system, a total of eight parts. The driving simulation system provides the driver with road view information and collects his operating instructions.

[0007] The power chassis domain integrated control system receives driver instructions, road environment and vehicle model information, as well as response information from each execution system of the power chassis and its load simulation device (including electric drive system, wire control brake system, wire control steering system, active suspension system), completes control decisions and sends control instructions to each execution system.

[0008] Each execution system of the power chassis and its load simulation device receive and execute the control instructions, and feed back the response status signal to the power chassis domain integrated control system.

[0009] The vehicle real-time simulation system provides vehicle dynamic response information for the power chassis domain integrated control system, and also provides road view information for the driving simulation system.

[0010] The test bench control system is responsible for test project management, test log recording, test data observation and calibration, and data analysis.

[0011] Signals are exchanged between systems through CAN bus, digital signals and analog signals.

[0012] Preferably, the driving simulation system includes components such as a steering wheel, a steering column and a steering wheel angle sensor, an accelerator pedal and an accelerator pedal opening sensor, a brake pedal and a brake pedal opening sensor, a display screen, a seat and a driving simulator bracket. The steering wheel angle sensor and the steering wheel are connected to the steering column, the brake pedal opening sensor is connected to the brake pedal, the accelerator pedal sensor is connected to the accelerator pedal, and the display screen, seat, brake pedal, accelerator pedal and steering column are all installed on the driving simulator bracket.

[0013] The driving simulation system collects the driver's steering wheel angle signal input through the steering wheel angle sensor, and collects the driver's brake pedal and accelerator pedal signal input through the brake and accelerator pedal opening sensors respectively, and simulates the real road view for the driver through the display screen.

[0014] Preferably, the electric drive system includes components such as a drive motor, a load motor, a gearbox, a torsional damper and a drive system bracket. The drive motor and the load motor are connected through a gearbox and a torsional damper, and the above components are fixed on the drive system bracket. The gearbox is adjusted to a fixed gear, and the torsional damper reduces the mechanical vibration of the output shaft of the drive motor to improve the stability of the electric drive system. The drive motor receives the required torque command of the power chassis domain integrated control system and responds through the torque control mode; the load motor receives the actual speed command of the power chassis domain integrated control system, and responds through the speed control mode to simulate the road load.

[0015] More preferably, the wire control brake system includes components such as an integrated electronic hydraulic brake, a hydraulic sensor, a brake line, a brake caliper, a brake disc and a brake system bracket. The brake line is connected to the integrated electronic hydraulic brake and the hydraulic sensor, the brake caliper and the hydraulic sensor respectively. The brake disc, the brake caliper and the integrated electronic hydraulic brake are respectively installed on the brake system bracket. The brake caliper is located above the brake disc, and there is a gap between the two.

[0016] During braking, the brake cylinder and various valves of the integrated electronic hydraulic brake receive control instructions from the power chassis domain integrated control system, the inlet valve opens, the outlet valve closes, the brake line is pressurized, the brake caliper contacts the brake disc and generates braking torque, and the hydraulic sensor monitors and feeds back the brake line pressure to the power chassis domain integrated control system; when braking is canceled, the inlet valve closes, the outlet valve opens, the brake line is depressurized, the braking torque is reduced to zero, and the brake caliper and brake disc are separated.

[0017] More preferably, the wire-controlled steering system comprises components such as a double-pinion wire-controlled steering machine, a steering resistance simulation electric cylinder, and a steering system bracket. The double-pinion wire-controlled steering machine and the steering resistance simulation electric cylinder are installed on the steering bracket, and a steering knuckle arm on one side of the steering machine is connected to a telescopic rod of the steering resistance simulation electric cylinder.

[0018] The steering gear receives the required front wheel angle command from the power chassis domain integrated control system, responds through the angle mode, and feeds back the response value to the integrated control system; the steering resistance simulation electric cylinder receives the required steering resistance command from the integrated control system, and generates steering resistance in the opposite direction of the steering knuckle arm movement through the torque control mode.

[0019] More preferably, the active suspension system includes components such as a continuously variable damper, a coil spring, a road excitation simulation electric cylinder, a force sensor, a displacement sensor, an acceleration sensor, and an active suspension bracket. The road excitation simulation electric cylinder is fixedly connected to the lower bracket of the active suspension system, performs reciprocating motion through a speed control mode, simulates road excitation, and adjusts the amplitude and frequency according to the road surface grade. The continuously variable damper and the coil spring are respectively connected to the upper bracket and the lower bracket of the active suspension system, the force sensor is located between the continuously variable damper and the upper bracket, and the acceleration sensor and the displacement sensor are respectively fixed to the upper bracket and the lower bracket.

[0020] The power chassis domain integrated control system receives signals from the force sensor, displacement sensor, and acceleration sensor respectively, and after calculation, sends control current to the continuously variable damper to achieve active suspension control.

[0021] More preferably, the power chassis domain integrated control system includes an integrated control module and a signal interaction module.

[0022] The integrated control module includes a vehicle motion control stability judgment layer, a vehicle motion integrated control layer, and an actuator and load control layer. The module is used to receive driver operation instructions, vehicle model and road environment information, and actuator response information to achieve vehicle motion stability judgment, integrated control, and actuator and load control.

[0023] The signal interaction module is used for signal interaction between the integrated control module and other systems. It mainly receives driver operation instructions, vehicle and road environment simulation information, actuator response information, and sends control instructions to each actuator.

[0024] More preferably, the vehicle motion stability judgment layer judges the lateral and longitudinal stability of the vehicle by a dissipated energy method; and judges the vertical stability by a roll gradient-pitch gradient-vertical vibration stability judgment method.

[0025] The dissipated energy method solves the three-degree-of-freedom nonlinear vehicle system differential equations of different vehicle states under the same road adhesion coefficient and front wheel turning angle offline, calculates the dissipated energy at the initial and final moments, and makes an energy diagram in three-dimensional space to determine the stratified threshold energy of lateral and longitudinal stability, thereby realizing the division of the boundaries between the stable zone and the unstable zone. On this basis, the stable zone is further divided into the critical instability zone and the stable zone. Among them, the nonlinear three-degree-of-freedom vehicle system differential equation is:

[0026]

[0027] Among them, m, L f ,L r and I z are vehicle parameters, representing the curb weight, the distance from the front and rear axles to the vehicle's center of mass, and the vehicle's moment of inertia around the z-axis; v x ,v y and is the vehicle motion state, representing the longitudinal velocity, lateral velocity and yaw angular velocity of the vehicle respectively; F yfl ,F yfr ,F yrl ,F yrr are the lateral forces of each tire of the vehicle; δ f is the front wheel turning angle. Since this formula is used to determine the XOY plane stability of the vehicle at different longitudinal speeds, it only considers the energy change of the vehicle system's spontaneous motion in a certain state, and does not consider the energy change caused by the driving and braking torque input and the air resistance.

[0028] The calculation formula for the lateral force of each wheel is:

[0029] F y,i =F z,i μDsin(Carctan(Bα i -E(Bα i -arctan(Bα i ))))

[0030] Among them, B, C, D and E are tire lateral force fitting coefficients, representing tire stiffness factor, shape factor, peak factor and curvature factor respectively; μ is the road adhesion coefficient; α i Represents the sideslip angle of each tire, i=fl,fr,rl,rr.

[0031] The side slip angles of the front and rear tires are calculated from the vehicle state and parameters:

[0032]

[0033] The calculation formula of the vertical force of each wheel is:

[0034]

[0035] Among them, a x ,a y ,a z are the longitudinal, lateral and vertical accelerations of the vehicle body, are the pitch and roll acceleration of the vehicle body, L w is the wheelbase, I y,I x is the moment of inertia of the vehicle around the X and Y axes, α and β are the longitudinal and lateral slopes, g is the acceleration due to gravity, and h is the height of the center of mass of the sprung mass.

[0036] The specific formula for calculating dissipated energy is:

[0037]

[0038] Among them, v x,0 ,v y,0 and is the vehicle motion state at the initial moment, v x,e ,v y,e and is the vehicle motion state at the final moment, ΔE is the dissipated energy,

[0039] The roll gradient-pitch gradient-vertical vibration stability judgment method calculates the roll gradient, pitch gradient and vertical vibration frequency of the vehicle through the lateral and longitudinal acceleration, roll angle and pitch angle of the vehicle, and makes a vehicle state judgment diagram in three-dimensional space to realize the vertical motion stability classification of the vehicle. The roll / pitch gradient calculation formula is:

[0040]

[0041] Among them, G pitch ,G roll are the pitch and roll gradients, θ and φ are the pitch and roll angles, respectively.

[0042] More preferably, the vehicle motion integrated control layer is controlled by an optimal control method based on a 14-DOF nonlinear vehicle model, and the 14-DOF nonlinear vehicle motion equation is:

[0043]

[0044] Among them, C f ,C r is the cornering stiffness of the front and rear wheels, C D is the drag coefficient, A is the windward area, ρ a is the air density, F d is the total driving force, M d is the additional yaw moment, F xfl ,F xfr ,F xrl ,F xrr is the longitudinal force of each wheel, F fl ,F fr ,F rl ,F rr is the suspension force at each wheel, m s is the sprung mass, z sis the vertical displacement of the sprung mass, m tfl ,m tfr ,m trl ,m trr is the unsprung mass, z rfl ,z rfr ,z rrl ,z rrr is the vertical displacement of the road surface under each wheel, z tfl ,z tfr ,z trl ,z trr is the vertical displacement of each unsprung mass, k tfl ,k tfr ,k trl ,k trr is the vertical stiffness of each tire, T df ,T dr is the driving torque of each axle, T bfl ,T bfr ,T brl ,T brr is the braking torque of each wheel, ω fl ,ω fr ,ω rl ,ω rr is the wheel speed, I w is the wheel moment of inertia, R w is the wheel radius,

[0045] The calculation formula for each suspension force is:

[0046]

[0047] Among them, z sfl ,z sfr ,z srl ,z srr is the vertical displacement of the sprung mass at each wheel, k sfl ,k sfr ,k srl ,k srr is the spring stiffness of the suspension at each wheel, c sfl ,c sfr ,c srl ,c srr is the damping coefficient at each wheel, F afl ,F afr ,F arl ,F arr It is the main force of the suspension at each wheel.

[0048] The motion equation of the 14-DOF vehicle model is rewritten into the state space equation form. The state space equation control quantity U = [δ f ,M d ,F d ,Fafl ,F afr ,F arl ,F arr ,T df ,T dr ,T bfl ,T bfr ,T brl ,T brr ], state quantity

[0049] The objective function of the optimal control problem is:

[0050] J=(YY ref )Q(YY ref ) T +ΔURΔU T

[0051] in, is the output, Y ref is the reference value of each output quantity, ΔU is the increment of each control quantity, Q, R are the weight matrices of output quantity and control quantity, both of which are positive definite matrices, reflecting the tracking performance of the controller and the stability of the output respectively.

[0052] The constraints are,

[0053]

[0054] Among them, U min ,U max and ΔU min ,ΔU max are the maximum and minimum values ​​of the control amount and control increment respectively,

[0055] The weight distribution principle of Q and R matrices is as follows: For lateral and longitudinal stability, when the vehicle is in the stable area, the longitudinal speed v is given priority. x Tracking performance, when the vehicle is in the critical stability area, as the stability gradually decreases, v x Tracking weight down, lateral velocity v y and yaw rate The weight increases, and when the vehicle is in an unstable area, only v is considered y , Tracking weight to ensure lateral stability of the vehicle; for vertical stability, vertical displacement z is given priority when the vehicle is in the stable area. s and vertical speed Tracking performance, ensuring vertical comfort, when the vehicle is in the critical stability area, as the stability gradually decreases, z s and Tracking weight decreases, pitch angle θ, roll angle φ and pitch angular velocity Roll angular velocity The weight increases. When the vehicle is in the unstable area, only θ, and φ, Tracking performance, giving priority to ensuring pitch and roll stability.

[0056] More preferably, the actuator and load control layer distribute the driving, braking and suspension forces by a method based on minimizing tire adhesion utilization, and the objective function is:

[0057]

[0058] Among them, F x,i ,F y,i ,F z,i are the longitudinal force, lateral force and vertical force of each tire respectively, i=fl,fr,rl,rr,

[0059] The constraints are:

[0060]

[0061] The allocation priority principle follows: When the vehicle's lateral and longitudinal stability is poor, priority is given to satisfying F x,i ; When vertical stability is poor, priority is given to satisfying F z,i .

[0062] More preferably, the vehicle real-time simulation system is used for simulation of road, environment and vehicle models.

[0063] The simulation system is used to receive the response signals of the power and chassis systems, complete the vehicle system dynamics and vehicle-road-environment joint simulation, and output the road environment information and vehicle status and parameter information.

[0064] The parameters in the simulation system are adjustable to adapt to different vehicle configurations and road environment scenarios.

[0065] More preferably, the test bench control system includes functions such as test project management, test data observation and calibration, etc.

[0066] The system can observe and analyze the driver's operating instructions, road environment and vehicle model information, and the key status of the integrated control algorithm, and calibrate the key parameters of the model and control algorithm. The system can also be used for test project management and daily test log recording.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] 1. The wire-controlled chassis has complete functions and a high degree of integration in the power chassis domain: The wire-controlled chassis electric vehicle hardware-in-the-loop simulation test bench and its power chassis domain integrated control architecture proposed in the present invention include not only a driving simulation system, but also cover the wire-controlled chassis and power system of the electric vehicle. Various actuators involve horizontal, longitudinal, vertical and other motion modes, and can support the coordination control algorithms of different actuators and power systems and the testing requirements of the integrated control algorithms in the power chassis domain. Compared with the existing technology, the wire-controlled chassis has more complete functions and a higher degree of integration in the power chassis domain.

[0069] 2. Wide coverage of test performance: The hardware-in-the-loop simulation test bench for the wire-controlled chassis electric vehicle and its integrated control architecture for the power chassis domain proposed in the present invention can not only test the integrated control algorithm for the power chassis domain, but also test and verify the coupling of multiple motion modes in the power chassis domain, multiple driving styles for the driver, and the underlying control algorithm for the actuator. Compared with the existing technology, the test performance coverage is wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a schematic diagram of the hardware-in-the-loop simulation test bench for the electric vehicle with a controlled-by-wire chassis and its integrated control architecture for the power chassis domain in the present invention;

[0071] Figure 2 It is a schematic diagram of the structure of the electric drive system in the present invention;

[0072] Figure 3 It is a schematic diagram of the structure of the wire control brake system in the present invention;

[0073] Figure 4 It is a schematic diagram of the structure of the wire control steering system in the present invention;

[0074] Figure 5 It is a schematic diagram of the structure of the active suspension system in the present invention;

[0075] Figure 6 A schematic diagram of weight distribution of vehicle lateral and longitudinal motion stability in the present invention;

[0076] Figure 7 Schematic diagram of the weight distribution of vehicle vertical motion stability in the present invention. DETAILED DESCRIPTION

[0077] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0078] The hardware-in-the-loop simulation test bench for the electric vehicle with a controlled-by-wire chassis and its power chassis integrated domain control architecture of this embodiment has the following workflow: Figure 1 As shown, it includes: driving simulation system, vehicle real-time simulation system, test bench measurement and control system, power chassis domain integrated control system, wire control brake system, wire control steering system, drive system, active suspension system and other actuator subsystems.

[0079] In this embodiment, the driving simulation system provides the driver with road view information and collects his operating instructions.

[0080] In this embodiment, the power chassis domain integrated control system receives driver commands, road environment and vehicle model information, as well as response information from each execution system of the power chassis and its load simulation device (including electric drive system, wire-controlled brake system, wire-controlled steering system, active suspension system), completes control decisions and issues control commands to each execution system.

[0081] In this embodiment, actuator subsystems such as the electric drive system and its load simulation motor, wire-controlled brake system, wire-controlled steering system and its load simulation electric cylinder, active suspension system and road load simulation electric cylinder receive and execute control instructions, and forward the real-time response sensor signals to the control module and the vehicle real-time simulation system via the power chassis domain integrated control system control instruction interaction module.

[0082] In this embodiment, the vehicle real-time simulation system provides the whole vehicle dynamic response information to the power chassis domain integrated control system, and provides the road view information to the driving simulation system.

[0083] In this embodiment, the test bench measurement and control system is responsible for test project management, test log recording, test data observation and calibration, and data analysis.

[0084] In this embodiment, signal interaction is performed between the systems via the CAN bus, digital signals and analog signals.

[0085] In this embodiment, the driving simulation system includes components such as a steering wheel, a steering column and a steering wheel angle sensor, an accelerator pedal and an accelerator pedal opening sensor, a brake pedal and a brake pedal opening sensor, a display screen, a seat and a driving simulator bracket.

[0086] In this embodiment, the driving simulation system collects the driver's steering wheel angle signal input through the steering wheel angle sensor, collects the driver's brake pedal and accelerator pedal signal input through the brake and accelerator pedal opening sensors respectively, and simulates the real road view for the driver through the display screen.

[0087] In this embodiment, the drive system includes a drive motor, a load motor and a drive system bracket, a torque sensor, a gearbox, a torsion damper and other components. The drive motor and the load towing motor are connected through a gearbox and the two are fixed on the drive system bracket. The above structure is as shown in FIG. Figure 2 shown.

[0088] In this embodiment, the working voltage of the drive motor and the load motor is provided by the EA analog power supply, and the working voltage of the motor controller and the gearbox controller is provided by a low-voltage adjustable power supply. The drive motor is controlled by a torque control mode, and the load motor is controlled by a speed control mode. The drive motor and the load motor respectively follow the total output torque of the power source and the wheel-end speed calculated by the real-time controller. At the same time, the gearbox adopts a fixed gear to realize the control of the towing motor test bench. The motor controller feeds back the motor speed, torque and other motor states in real time, and records the data through CANape.

[0089] In this embodiment, the wire control brake system includes components such as an integrated electronic hydraulic brake, a hydraulic sensor, a brake line, a brake caliper, a brake disc brake system bracket, etc. The integrated electronic hydraulic brake integrates a brake motor and 14 high-speed switching valves including 4 boost valves, 4 pressure reducing valves, 2 motor isolation valves, 2 master cylinder isolations and 2 pedal isolation valves. The integrated control system controls it through the CAN bus.

[0090] In this embodiment, the brake pipeline is respectively connected to the integrated electronic hydraulic brake and the hydraulic sensor, the brake caliper and the hydraulic sensor.

[0091] In this embodiment, the brake disc, brake caliper and integrated electronic hydraulic brake are respectively mounted on the brake system bracket, and the brake caliper is located above the brake disc with a gap between the two. When the brake is pressurized, the brake caliper contacts the brake disc and generates a braking torque. When the brake is depressurized, the braking torque decreases until it is zero, and the two are separated. The above structure is as shown in FIG. Figure 3 shown.

[0092] In this embodiment, the brake-by-wire system realizes independent control of the braking torque of each wheel by sending control instructions to 14 high-speed switch valves and brake motors through the power chassis domain integrated control system. The working process of the brake-by-wire system in this mode is explained by taking the left front wheel boost as an example: the power chassis domain integrated control system sends an energy storage instruction to control the brake cylinder to build pressure, open the motor isolation valve and the left front wheel boost valve respectively, and close the left front wheel pressure reducing valve to realize the boost of the left front wheel. The left front wheel brake hydraulic pressure is collected through the left front wheel pressure sensor, and the signal is sent to the power chassis domain integrated control system to complete the closed-loop control of the left front wheel brake pressure.

[0093] In this embodiment, the wire-controlled steering system includes components such as a double-pinion wire-controlled steering machine, a steering resistance simulation electric cylinder, and a steering system bracket. The double-pinion wire-controlled steering machine and the steering resistance simulator are installed on the steering system. A steering knuckle arm on one side of the steering machine is connected to the telescopic rod of the steering resistance simulation electric cylinder. The steering resistance simulation electric cylinder is in a torque control mode and generates a steering resistance opposite to the movement direction of the steering knuckle arm. The above structure is as shown in FIG. Figure 4 shown.

[0094] In this embodiment, the steer-by-wire system can combine the vehicle, road model and power chassis domain integrated control system to achieve hardware-in-the-loop simulation of the steer-by-wire actuator.

[0095] In this embodiment, the steering resistance is calculated by the maximum rack force, which mainly includes the steering system resistance F f , Tire aligning torque M z and tire steering resistance torque M r , the calculation formula is as follows:

[0096]

[0097] Where s is the effective force ratio of the steering trapezoid at the extreme position, which is taken as 200mm; the steering system resistance is related to the rack pressure block force and the piston seal resistance, and the maximum value F is taken. f =450N.

[0098] In this embodiment, the tire steering resistance torque M r Obtained by semi-empirical formula:

[0099]

[0100] Where p is the tire pressure, which is 0.22MP, μ is the sliding friction coefficient between the tire and the road, which is 0.3 to 0.8, G l It is the vertical load of the steering axle, in N. This parameter mainly depends on the vehicle weight and axle load distribution.

[0101] In this embodiment, the tire aligning torque M z The magic formula is used for estimation, and the calculation formula is as follows:

[0102] M z,i =F z,i D z sin(C z atan(B z α i +E z (B z α i -atan(B z α i ))))

[0103] In the formula, F z,i Refers to the vertical load of each wheel, B z , C z , D z 、E z are the stiffness factor, shape factor, peak factor and curvature factor of the magic formula of tire self-aligning torque, α i Refers to the slip angle of each wheel, i = fl, fr, rl, rr,

[0104] The calculation formula of each wheel slip angle is as follows:

[0105]

[0106] In this embodiment, the workflow of front wheel angle control by the wire-controlled steer system is as follows: the integrated control module in the power chassis domain integrated control system sends the required front wheel angle to the actuator control command layer; after the actuator control command layer calculates the steering resistance torque, it sends the required front wheel angle and required steering resistance control instructions to the wire-controlled steer system through the CAN bus; then, the steering gear and steering resistance simulation electric cylinders are actuated respectively to achieve control instruction response, and the front wheel angle response signal is fed back to the power chassis domain integrated control system in real time, thereby completing closed-loop control of the front wheel angle.

[0107] In this embodiment, the active suspension system includes components such as a continuously variable damper, a coil spring, a road excitation simulation electric cylinder, a force sensor, a displacement sensor, an acceleration sensor and an active suspension bracket. The road excitation simulation electric cylinder is fixedly connected to the lower bracket of the active suspension system and realizes reciprocating motion through a speed control mode.

[0108] In this embodiment, the road excitation is simulated, the continuously variable damper and the coil spring are connected to the upper bracket and the lower bracket of the active suspension system respectively, the force sensor is located between the continuously variable damper and the upper bracket, and the acceleration sensor and the displacement sensor are fixed to the upper bracket and the lower bracket respectively. The above system structure is as follows: Figure 5 shown.

[0109] In this embodiment, the working process of the active suspension system is as follows: the road excitation simulation electric cylinder is actuated to simulate road excitation, driving the upper and lower brackets, coil springs and continuously variable dampers to vibrate. Among them, the lower bracket simulates the vibration of the unsprung mass, and the upper bracket simulates the vibration of the sprung mass. The acceleration signal and displacement signal of the simulated sprung mass and the simulated unsprung mass are respectively collected in real time through the acceleration sensor, displacement sensor and force sensor, and the damping force signal can be collected in real time through the force sensor.

[0110] In this embodiment, the acceleration signal, displacement signal and force signal collected by the sensor are sent to the power chassis domain integrated control system to realize the observation of the suspension vibration state, and the vehicle motion integrated control layer performs real-time calculation to realize the decision of the suspension main force. The actuator and load control layer adjusts the control current and oil pump pressure of the continuously variable damper according to the required size of the suspension main force, thereby realizing closed-loop control of the active suspension.

[0111] In this embodiment, a 1 / 4 vehicle vertical model is used as an example to perform active suspension control, and the motion differential equation is as follows:

[0112]

[0113] Among them, since the vibration table is fixedly connected to the unsprung mass, the tire has no deformation, and the tire force k t (qz w ) and the vibration table thrust F v Consistent, damping force F c It can be measured by a force sensor, so the above motion equation can be rewritten as:

[0114]

[0115] In the formula, m b ,m w and unsprung mass, respectively, s is the coil spring stiffness, F c and F v are the damping force and the vibration table thrust, respectively, which are measured by the sensor and obtained by the road excitation simulation electric cylinder feedback, w ,z b and are the displacement and acceleration of the sprung and unsprung masses, respectively, measured by sensors.

[0116] In this embodiment, the power chassis domain integrated control system includes an integrated control module and a signal interaction module;

[0117] In this embodiment, the integrated control module includes a vehicle motion control stability judgment layer, a vehicle motion integrated control layer, and an actuator and load control layer. The module receives driver operation instructions and vehicle model, road / environmental information respectively to realize vehicle motion control stability analysis, integrated control and actuator control.

[0118] In this embodiment, the signal interaction module is used for signal interaction between the integrated control module and other systems, mainly receiving driver operation instructions, vehicle and road environment simulation information, actuator response information, and sending control instructions to each actuator.

[0119] In this embodiment, the vehicle motion control stability judgment layer in the integrated control module determines the lateral and longitudinal motion stability of the vehicle by the dissipated energy method; and determines the vertical motion stability of the vehicle by the roll gradient-pitch gradient-vertical vibration stability judgment method.

[0120] The dissipated energy method solves the three-degree-of-freedom nonlinear vehicle system differential equations of different vehicle states under the same road adhesion coefficient and front wheel turning angle offline, calculates the dissipated energy at the initial and final moments, and makes an energy diagram in three-dimensional space to determine the stratification threshold energy ΔE th , thereby realizing the division of the boundary between the stable area and the unstable area. On this basis, the stable area is further divided into the critical instability area and the stable area. In this embodiment, the boundary is taken as 0.9ΔE th Among them, the nonlinear three-degree-of-freedom vehicle system differential equation is:

[0121]

[0122] Among them, m, L f ,L r and I z are vehicle parameters, representing the curb weight, the distance from the front and rear axles to the vehicle's center of mass, and the vehicle's moment of inertia around the z-axis; v x ,v y and is the vehicle motion state, representing the longitudinal velocity, lateral velocity and yaw angular velocity of the vehicle respectively; F yfl ,F yfr ,F yrl ,F yrr are the lateral forces of each tire of the vehicle; δ f is the front wheel turning angle. Since this formula is used to determine the XOY plane stability of the vehicle at different longitudinal speeds, it only considers the energy change of the vehicle system's spontaneous motion in a certain state, and does not consider the energy change caused by the driving and braking torque input and the air resistance.

[0123] The specific formula for calculating dissipated energy is:

[0124]

[0125] Among them, v x,0 ,v y,0 and is the vehicle motion state at the initial moment, v x,e ,v y,e and is the vehicle motion state at the final moment, and ΔE is the dissipated energy.

[0126] The roll gradient-pitch gradient-vertical vibration stability judgment method calculates the roll gradient, pitch gradient and vertical vibration frequency of the vehicle through the lateral and longitudinal acceleration, roll angle and pitch angle of the vehicle, and makes a vehicle state judgment diagram in three-dimensional space to realize the vertical motion stability classification of the vehicle. The roll / pitch gradient calculation formula is:

[0127]

[0128] In the formula, G pit ,G roll are the pitch and roll gradients, θ and φ are the pitch and roll angles, respectively. x ,a y are the lateral and longitudinal accelerations of the vehicle, respectively.

[0129] In this embodiment, the vehicle motion integrated control is realized based on the model predictive control algorithm of the 14-DOF nonlinear vehicle model. The motion equation of the 14-DOF nonlinear vehicle is:

[0130]

[0131] Among them, C f ,C r is the cornering stiffness of the front and rear wheels, C D is the drag coefficient, A is the windward area, ρ a is the air density, F d is the total driving force, M d is the additional yaw moment, F xfl ,F xfr ,F xrl ,F xrr is the longitudinal force of each wheel, F fl ,F fr ,F rl ,F rr is the suspension force at each wheel, L w is the wheelbase, m s is the sprung mass, I y ,I x is the moment of inertia of the vehicle around the X and Y axes, α and β are the longitudinal and lateral slopes, g is the acceleration due to gravity, h is the height of the center of mass of the sprung mass, and z s is the vertical displacement of the sprung mass, m tfl ,m tfr ,m trl ,m trr is the unsprung mass, z rfl ,z rfr ,z rrl ,z rrr is the vertical displacement of the road surface under each wheel, z tfl ,z tfr ,ztrl ,z trr is the vertical displacement of each unsprung mass, k tfl ,k tfr ,k trl ,k trr is the vertical stiffness of each tire, T df ,T dr is the driving torque of each axle, T bfl ,T bfr ,T brl ,T brr is the braking torque of each wheel, ω fl ,ω fr ,ω rl ,ω rr is the wheel speed, I w is the wheel moment of inertia, R w is the wheel radius.

[0132] The calculation formula for each suspension force is:

[0133]

[0134] Among them, z sfl ,z sfr ,z srl ,z srr is the vertical displacement of the sprung mass at each wheel, k sfl ,k sfr ,k srl ,k srr is the spring stiffness of the suspension at each wheel, c sfl ,c sfr ,c srl ,c srr is the damping coefficient at each wheel, F afl ,F afr ,F arl ,F arr It is the main driving force of the suspension at each wheel.

[0135] The motion equation of the 14-DOF vehicle model is rewritten into the state space equation form. The state space equation control quantity U = [δ f ,M d ,F d ,F afl ,F afr ,F arl ,F arr ,T df ,T dr ,T bfl ,T bfr ,T brl ,T brr ], state quantity

[0136] The objective function of the model predictive control algorithm is:

[0137]

[0138] in, is the output, Y ref is the reference value of each output quantity, ΔU is the increment of each control quantity, Q, R are the weight matrices of output quantity and control quantity, both of which are positive definite matrices, reflecting the tracking performance of the controller and the stability of the output, N p ,N c They are prediction step length and control step length respectively. In this embodiment, N p =5,N c =3.

[0139] The constraints are:

[0140]

[0141] Among them, U min ,U max and ΔU min ,ΔU msx are the maximum and minimum values ​​of the control amount and control increment respectively.

[0142] Q, R matrix weight distribution principle: For the vehicle's lateral and longitudinal motion stability, the weight distribution principle is as follows: Figure 6 As shown, when the vehicle is in the stable area, the longitudinal speed v is given priority. x Tracking performance, longitudinal velocity weight γ x =1, lateral stability weight As the stability decreases, When the vehicle is in the critical stability region, as the stability gradually decreases, the longitudinal velocity weight γ c Gradually decrease, 0<γ c <1, lateral stability weight When the vehicle is in the unstable region, only v y , Tracking weights, To ensure the lateral stability of the vehicle; for the vertical stability of the vehicle, the weight distribution principle is as follows Figure 7 As shown, when the vehicle is in the stable area, the vertical displacement z is given priority. d and vertical speed Tracking performance, vertical weight γ z =1, to ensure comfort, pitch angle θ, roll angle φ and pitch angle velocity Roll angular velocity Weight γ θ,φ Gradually increases, 0<γ θ,φ<1; when the vehicle is in the critical stability area, as the stability gradually decreases, the vertical weight γ z Gradually decrease, 0<γ z <1, pitch, roll weight γ θ,φ =1; when the vehicle is in the unstable area, only θ, and φ, Tracking performance, giving priority to pitch and roll stability, γ θ,φ =1,γ z =0.

[0143] In this embodiment, the actuator and load control layer distribute the driving, braking, and suspension forces based on the minimum tire adhesion utilization. The objective function of the optimization distribution problem is:

[0144]

[0145] Among them, F x,i ,F y,i ,F z,i They are the longitudinal force, lateral force and vertical force of each tire respectively, i=fl,fr,rl,rr.

[0146] The constraints are:

[0147]

[0148] Where μ is the road adhesion coefficient.

[0149] The principle of allocating priorities follows: When the vehicle's lateral and longitudinal stability χ sta,XOY When the sta,XOY < sta,Z When F x,i ; When the vehicle vertical motion stability χ sta,Z When the sta,XOY ≥χ sta,Z When F z,i .

[0150] In this embodiment, the vehicle real-time simulation system is used to simulate the road, environment and vehicle model. The simulation system is used to receive the response signals of the power and chassis systems, complete the vehicle system dynamics and vehicle-road-environment joint simulation, and output road environment information and vehicle status and parameter information. The parameters in the simulation system are adjustable to adapt to different vehicle configurations and road environment scenarios.

[0151] In this embodiment, the test bench measurement and control system includes functions such as test project management, observation and calibration of test data. The system can observe and analyze data on driver operating instructions, road environment and vehicle model information, and key states of the integrated control algorithm, and calibrate key parameters of the model and control algorithm. The system can also be used for test project management and recording of daily test logs.

[0152] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture, characterized in that: include: Driving simulation system, electric drive system, wire-controlled brake system, wire-controlled steering system, active suspension system, power chassis domain integrated control system, vehicle real-time simulation system and test bench measurement and control system, The driving simulation system provides the driver with road visual information and collects his operating instructions; The power chassis domain integrated control system receives driver instructions, road environment and vehicle model information, response information of each execution system of the power chassis and its load simulation device, and parameter calibration of the test bench measurement and control system, completes control decisions and issues control instructions to each execution system. The power chassis execution systems and their load simulation devices include an electric drive system, a wire-controlled brake system, a wire-controlled steering system, and an active suspension system. Each execution system of the power chassis and its load simulation device receive and execute the control command, and feed back the response status signal to the power chassis domain integrated control system; The vehicle real-time simulation system provides the vehicle dynamics response information for the power chassis domain integrated control system, completes the vehicle system dynamics and vehicle-road-environment joint simulation, and outputs the road environment information and vehicle status and parameter information, while providing the driving simulation system with road vision information; The test bench measurement and control system is responsible for test project management, test log recording, test data observation and calibration, and data analysis. The system can observe and analyze the driver's operating instructions, road environment and vehicle model information, and key states of the integrated control algorithm, and calibrate the key parameters of the model and control algorithm; Signals are exchanged between systems through CAN bus, digital signals and analog signals.

2. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 1, characterized in that: The driving simulation system includes a steering wheel, a steering column and a steering wheel angle sensor, an accelerator pedal and an accelerator pedal opening sensor, a brake pedal and a brake pedal opening sensor, a display screen, a seat and a driving simulator. The steering wheel angle sensor and the steering wheel are connected to the steering column, the brake pedal opening sensor is connected to the brake pedal, and the accelerator pedal sensor is connected to the accelerator pedal. The display screen, the seat, the brake pedal, the accelerator pedal and the steering column are all installed on a driving simulator bracket. The driving simulation system collects the driver's steering wheel angle signal input through the steering wheel angle sensor, collects the driver's brake pedal and accelerator pedal signal input through the brake and accelerator pedal opening sensors respectively, and simulates a real road scene for the driver through the display screen.

3. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 1, characterized in that: The electric drive system includes a drive motor, a load motor, a gearbox, a torsional damper and a drive system bracket. The drive motor and the load motor are connected through the gearbox and the torsional damper. The above components are all fixed on the drive system bracket. The drive motor receives the required torque instruction of the power chassis domain integrated control system and responds through the torque control mode; the load motor receives the actual speed instruction of the power chassis domain integrated control system and responds through the speed control mode to simulate the road load.

4. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 1, characterized in that: The wire control brake system includes an integrated electronic hydraulic brake, a hydraulic sensor, a brake caliper, a brake disc, a brake pipeline and a brake system bracket, wherein the integrated electronic hydraulic brake and the hydraulic sensor, the brake caliper and the hydraulic sensor are connected respectively, and the brake disc, the brake caliper and the integrated electronic hydraulic brake are respectively mounted on the brake system bracket, and the brake caliper is located above the brake disc, with a gap between the two. During braking, the brake cylinder and various valves of the integrated electronic hydraulic brake receive control instructions from the power chassis domain integrated control system, the inlet valve opens, the outlet valve closes, the brake line is pressurized, the brake caliper contacts the brake disc and generates braking torque, and the hydraulic sensor monitors and feeds back the brake line pressure to the power chassis domain integrated control system; when braking is canceled, the inlet valve closes, the outlet valve opens, the brake line is depressurized, the braking torque is reduced to zero, and the brake caliper and brake disc are separated.

5. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 1, characterized in that: The wire-controlled steering system includes a double-pinion wire-controlled steering gear, a steering resistance simulation electric cylinder and a steering system bracket. The double-pinion wire-controlled steering gear and the steering resistance simulation electric cylinder are installed on the steering bracket. A steering knuckle arm on one side of the steering gear is connected to the telescopic rod of the steering resistance simulation electric cylinder. The steering gear receives the required front wheel angle command from the power chassis domain integrated control system, responds through an angle mode, and feeds back the response value to the integrated control system; the steering resistance simulation electric cylinder receives the required steering resistance command from the integrated control system, and generates a steering resistance opposite to the movement direction of the steering knuckle arm through a torque control mode.

6. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 1, characterized in that: The active suspension system includes a continuously variable damper, a coil spring, a road excitation simulation electric cylinder, a force sensor, a displacement sensor, an acceleration sensor and an active suspension bracket. The road excitation simulation electric cylinder is fixedly connected to the lower bracket of the active suspension system, performs reciprocating motion through a speed control mode, simulates road excitation, and adjusts the amplitude and frequency according to the road surface grade. The continuously variable damper and the coil spring are respectively connected to the upper bracket and the lower bracket of the active suspension system. The force sensor is located between the continuously variable damper and the upper bracket. The acceleration sensor and the displacement sensor are respectively fixed to the upper bracket and the lower bracket. The power chassis domain integrated control system receives signals from the force sensor, displacement sensor, and acceleration sensor respectively, and sends control current to the continuously variable damper after calculation to achieve control of the active suspension. The power chassis domain integrated control system includes an integrated control module and a signal interaction module.

7. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 1, characterized in that: The integrated control module includes a vehicle motion control stability judgment layer, a vehicle motion integrated control layer, and an actuator and load control layer. The module is used to receive driver operation instructions, vehicle model and road environment information, and actuator response information to achieve vehicle motion stability judgment, integrated control, and actuator and load control. The signal interaction module is used for signal interaction between the integrated control module and other systems. It mainly receives driver operation instructions, vehicle and road environment simulation information, actuator response information, and sends control instructions to each actuator.

8. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 7, characterized in that: The vehicle motion stability judgment layer judges the lateral and longitudinal stability of the vehicle by the dissipated energy method; judges the vertical stability by the roll gradient-pitch gradient-vertical vibration stability judgment method, The dissipated energy method solves the three-degree-of-freedom nonlinear vehicle system differential equations of different vehicle states under the same road adhesion coefficient and front wheel turning angle offline, calculates the dissipated energy at the initial and final moments, and makes an energy diagram in three-dimensional space to determine the stratified threshold energy of lateral and longitudinal stability, thereby realizing the division of the boundary between the stable zone and the unstable zone. On this basis, the stable zone is further divided into the critical instability zone and the stable zone. The nonlinear three-degree-of-freedom vehicle system differential equation is: Among them, m, L f ,L r and I z are vehicle parameters, representing the curb weight, the distance from the front and rear axles to the vehicle's center of mass, and the vehicle's moment of inertia around the z-axis; v x ,v y and is the vehicle motion state, representing the longitudinal velocity, lateral velocity and yaw angular velocity of the vehicle respectively; F yfl ,F yfr ,F yrl ,F yrr are the lateral forces of each tire of the vehicle; δ f is the front wheel turning angle. Since this formula is used to determine the XOY plane stability of the vehicle at different longitudinal speeds, it only considers the energy change of the vehicle system's spontaneous motion in a certain state, and does not consider the energy change caused by the driving and braking torque input and the air resistance. The calculation formula for the lateral force of each wheel is: F y,i =F z,i μDsin(Carctan(Bα i -E(Bα i -arctan(Bα i )))) Among them, B, C, D and E are tire lateral force fitting coefficients, representing tire stiffness factor, shape factor, peak factor and curvature factor respectively; μ is the road adhesion coefficient; α i Represents the side slip angle of each tire, i = fl, fr, rl, rr, The side slip angles of the front and rear tires are calculated from the vehicle state and parameters: The calculation formula of the vertical force of each wheel is: Among them, a x ,a y ,a z are the longitudinal, lateral and vertical accelerations of the vehicle body, are the pitch and roll acceleration of the vehicle body, L w is the wheelbase, I y ,I x is the moment of inertia of the vehicle around the X and Y axes, α and β are the longitudinal and lateral slopes, g is the acceleration of gravity, h is the height of the center of mass of the sprung mass, The specific formula for calculating dissipated energy is: Among them, v x,0 ,v y,0 and is the vehicle motion state at the initial moment, v x,e ,v y,e and is the vehicle motion state at the final moment, ΔE is the dissipated energy, The roll gradient-pitch gradient-vertical vibration stability judgment method calculates the roll gradient, pitch gradient and vertical vibration frequency of the vehicle through the lateral and longitudinal acceleration, roll angle and pitch angle of the vehicle, and makes a vehicle state judgment diagram in three-dimensional space to realize the vertical motion stability classification of the vehicle. The roll / pitch gradient calculation formula is: Among them, G pitch ,G roll are the pitch and roll gradients, θ and φ are the pitch and roll angles, respectively.

9. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 8, characterized in that: The vehicle motion integrated control layer realizes control through an optimal control method based on a 14-DOF nonlinear vehicle model. The 14-DOF nonlinear vehicle motion equation is: Among them, C f ,C r is the cornering stiffness of the front and rear wheels, C D is the drag coefficient, A is the windward area, ρ a is the air density, F d is the total driving force, M d is the additional yaw moment, F xfl ,F xfr ,F xrl ,F xrr is the longitudinal force of each wheel, F fl ,F fr ,F rl ,F rr is the suspension force at each wheel, m s is the sprung mass, z s is the vertical displacement of the sprung mass, m tfl ,m tfr ,m trl ,m trr is the unsprung mass, z rfl ,z rfr ,z rrl ,z rrr is the vertical displacement of the road surface under each wheel, z tfl ,z tfr ,z trl ,z trr is the vertical displacement of each unsprung mass, k tfl ,k tfr ,k trl ,k trr is the vertical stiffness of each tire, T df ,T dr is the driving torque of each axle, T bfl ,T bfr ,T brl ,T brr is the braking torque of each wheel, ω fl ,ω fr ,ω rl ,ω rr is the wheel speed, I w is the wheel moment of inertia, R w is the wheel radius, The calculation formula for each suspension force is: Among them, z sfl ,z sfr ,z srl ,z srr is the vertical displacement of the sprung mass at each wheel, k sfl ,k sfr ,k srl ,k srr is the spring stiffness of the suspension at each wheel, c sfl ,c sfr ,c srl ,c srr is the damping coefficient at each wheel, F afl ,F afr ,F arl ,F arr It is the main driving force of the suspension at each wheel. The motion equation of the 14-DOF vehicle model is rewritten into the state space equation form. The state space equation control quantity U = [δ f ,M d ,F d ,F afl ,F afr ,F arl ,F arr ,T df ,T dr ,T bfl ,T bfr ,T brl ,T brr ], state quantity The objective function of the optimal control problem is: J=(Y-Y ref )Q(Y-Y ref ) T +ΔURΔU T in, is the output, Y ref is the reference value of each output quantity, ΔU is the increment of each control quantity, Q, R are the weight matrices of output quantity and control quantity, both of which are positive definite matrices, reflecting the tracking performance of the controller and the stability of the output respectively. The constraints are, Among them, U min ,U max and ΔU min ,ΔU max are the maximum and minimum values ​​of the control amount and control increment respectively, The weight distribution principle of Q and R matrices is as follows: For lateral and longitudinal stability, when the vehicle is in the stable area, the longitudinal speed v is given priority. x Tracking performance, when the vehicle is in the critical stability area, as the stability gradually decreases, v x Tracking weight down, lateral velocity v y and yaw rate The weight increases, and when the vehicle is in an unstable area, only v is considered y , Tracking weight to ensure lateral stability of the vehicle; for vertical stability, vertical displacement z is given priority when the vehicle is in the stable area. s and vertical speed Tracking performance, ensuring vertical comfort, when the vehicle is in the critical stability area, as the stability gradually decreases, z s and Tracking weight decreases, pitch angle θ, roll angle φ and pitch angular velocity Roll angular velocity The weight increases. When the vehicle is in the unstable area, only θ, and φ, Tracking performance, giving priority to ensuring pitch and roll stability.

10. The hardware-in-the-loop simulation test bench for a wire-controlled chassis electric vehicle and its power chassis domain integrated control architecture according to claim 7, characterized in that: The actuator and load control layer distributes the driving, braking and suspension forces based on the method of minimizing tire adhesion utilization, and the objective function is: Among them, F x,i ,F y,i ,F z,i are the longitudinal force, lateral force and vertical force of each tire respectively, i=fl,fr,rl,rr, The constraints are: The allocation priority follows the principle: When the vehicle's lateral and longitudinal stability is poor, priority is given to satisfying F x,i ; When vertical stability is poor, priority is given to satisfying F z,i .

Images