Vehicle active suspension control method capable of being used for flexible chassis expansion connection and application of vehicle active suspension control method

Abstract

The invention discloses a vehicle active suspension control method for flexible chassis expansion connection. The vehicle active suspension control method comprises the steps that a whole vehicle dynamic model is built, a dynamic control model of a single active suspension system is built, and a consensus algorithm is adopted to design a distributed control strategy. Wherein the built whole vehicle dynamic model comprises dynamic models of a vehicle body and all active suspension systems; establishing a dynamics control model of a single active suspension system, wherein the dynamics control model comprises a dynamics model of a vehicle body module and a dynamics control model of a single wheel suspension module; the design of the distributed control strategy comprises the steps of designing a control strategy for a dynamic control model of a single active suspension system, and realizing the optimal control of the whole vehicle by adopting a consensus algorithm. According to the method, the optimal control of the dynamic parameters of the whole vehicle under various continuous random road conditions can be realized, the vehicle driving smoothness and the operation stability are improved, the calculation cost and the calculation time of an active suspension control system are greatly reduced, and the requirement on an active suspension controller is reduced.

Description

Technical Field

[0001] The present invention relates to the field of vehicle active suspension control, and specifically relates to a vehicle active suspension control method and application thereof that can be used for flexible chassis expansion connection. Background Art

[0002] The automobile chassis consists of a drive system, a brake system, a steering system, and a suspension system. As the part of the vehicle that contacts the ground, its comprehensive performance has a decisive influence on the safety and comfort of the vehicle during driving. At present, higher requirements are put forward for the flexibility, comfort, and riding space of the vehicle in the design of the whole vehicle. In order to adapt to different driving scenarios and task requirements more flexibly, it is necessary to propose a new chassis system with stronger versatility, modular design, and modular control. The automobile flexible chassis refers to a new chassis composed of functional modules such as drive, brake, steering, suspension, and control. It adopts modular design, scalable structure, universal electronic and electrical architecture, and multi-modal control, so that the vehicle can flexibly adapt to different driving scenarios and task requirements.

[0003] As an important assembly of the automobile chassis, automobile suspension has a great impact on the smoothness and handling stability of the car during driving. Passive suspension has been widely used in most passenger cars due to its advantages such as low cost and no energy consumption. However, passive suspension cannot change the stiffness and damping of the suspension in real time according to the dynamic characteristics of the car during movement, nor can it output active control force, resulting in the inability of passive suspension to adjust its control effect according to road conditions and body dynamic characteristics. Under rapidly changing road conditions, the control effect on the dynamic characteristics of the body is poor. Semi-active suspension uses lower energy consumption to control the stiffness or damping of the suspension, thereby achieving better control effect than passive suspension. At present, the cost of semi-active suspension is constantly decreasing, and the application of semi-active suspension in automobiles is becoming more and more extensive. Semi-active suspension with air spring plus magnetorheological damper and air spring plus CDC damper has been widely used in mid-to-high-end passenger cars. However, semi-active suspension has not yet gotten rid of the traditional suspension "stiffness-damping" mode, and has limited effect on improving smoothness and handling, making it difficult to achieve a higher quality riding experience. Compared with the first two, active suspension has better control effect, and can output active control force when the car is driving, directly acting on the car body to achieve better control effect on ride comfort. However, active suspension currently has disadvantages such as high energy consumption, complex structure, high cost, and the arrangement of actuators such as motors on the suspension also has problems. These problems and shortcomings of active suspension have largely limited the popularity of active suspension in passenger cars, and it has only been used in a few high-end models.

[0004] Active suspension can output active control force in real time according to the input of the road surface to the wheels and the changes in the dynamic characteristics of the vehicle body. Its complex functions put forward high requirements on the control algorithm of active suspension. Proportional-integral-derivative (PID) is a typical control algorithm with advantages such as fast response and simple design, but when dealing with nonlinear problems during suspension vibration, the control accuracy is low and the stability is poor; Linear Quadratic Regulator (LQR) can effectively deal with multi-input and multi-output problems, but when solving the optimal feedback matrix, it cannot consider the constraints of the control quantity, which may cause the output force to exceed the maximum force that the actuator can actually provide, causing model distortion; Model Predictive Control (MPC) is a model-based optimal control algorithm, which has been widely used in scenarios such as path planning of intelligent connected vehicles. For suspension systems, the predictive characteristics of MPC and its ability to consider hardware constraints by setting limits on the control quantity have made it widely concerned in the control of the suspension field. However, MPC has high requirements on the computing performance of the on-board controller and the time cost of calculation is high, making it difficult to achieve real-time control of the suspension system while the vehicle is driving. Currently, the use of MPC to control the suspension has been widely studied, but the above factors limit the application of model predictive control in automobile suspension control.

[0005] As the application scenarios and mission requirements of vehicles become more and more extensive, different scenarios and tasks have different requirements for the number of axles of the whole vehicle. The traditional centralized control architecture needs to consider the number of axles of the whole vehicle when modeling the control model in the early stage of design. If the number of axles changes, the entire control architecture will be redesigned. At the same time, since the centralized control architecture needs to use a single control unit to control the entire chassis system, although it can theoretically achieve the global optimal control performance, its high integration, difficulty in function expansion, and excessive calculation limit the application of the centralized control architecture. As a new chassis system with stronger versatility, modular design and modular control, the automotive flexible chassis adopts modular design, scalable structure, universal electronic and electrical architecture and multi-modal control to distribute the traditional entire chassis system control problem to each subsystem for solution. It can flexibly adapt to different driving scenarios and mission requirements while greatly reducing the control amount of the entire control system, which has very important research significance. However, the traditional centralized control method obviously cannot be used for flexible chassis systems because it solves the output of all controllers at the same time. There is an urgent need for a modular control strategy suitable for a flexible chassis, which can individually control each module in the chassis system and achieve optimal control of the entire vehicle through communication between each module. Summary of the invention

[0006] In order to solve the above-mentioned problems in active suspension control and application, the present invention proposes a vehicle active suspension control method for flexible chassis extension connection, in order to achieve optimal control of the dynamic parameters of the whole vehicle under various continuous random road conditions, while improving the vehicle's ride smoothness and handling stability, thereby greatly reducing the calculation cost and calculation time of the active suspension control system, and reducing the requirements for the active suspension controller and the application cost.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme:

[0008] The vehicle active suspension control method for flexible chassis extension connection of the present invention is characterized in that it is carried out according to the following steps:

[0009] Step 1: for a multi-axle vehicle active suspension system of a whole vehicle, respectively establish the motion differential equations of the wheel suspension module and the body module of the whole vehicle; wherein the motion differential equation of the wheel suspension module of the whole vehicle includes: the vertical motion equation of the wheel;

[0010] The motion differential equations of the vehicle body module include: the vertical, pitch and roll motion equations of the vehicle body;

[0011] Step 2: Establish the correlation equation between the differential equations of motion of the wheel suspension module and the body module, so as to obtain the force generated by the suspension system and output to the body, and the vertical displacement generated by the vertical, pitch and roll motions of the body and output to the single active suspension system;

[0012] Step 3: Based on the motion differential equations and correlation equations of the wheel suspension module and the body module, a vehicle dynamics model is established, and a dynamics control model of a single active suspension system is constructed;

[0013] The vehicle dynamics model includes: a dynamics model of the vehicle body and all active suspension systems;

[0014] The dynamics control model of the single active suspension system includes: a dynamics model of a body module and a dynamics control model of a single wheel suspension module;

[0015] Step 4: Based on the dynamic control model of a single wheel suspension module, taking the optimal posture of the whole vehicle as the objective function and the dynamic response of the whole vehicle body as the control state quantity, a model predictive control strategy is adopted to control any single active suspension system, thereby obtaining the active control force output by the single active suspension system;

[0016] Step 5: Use the influence of each wheel suspension module on the vertical acceleration of the vehicle center of mass and the roll and pitch angle acceleration of the vehicle body as the consensus quantity between the wheel suspension modules, and use the consensus algorithm to adjust the active control force output by each active suspension system, obtain the adjusted active control force and output it, so as to achieve the optimal control of the active suspension system of the multi-axle vehicle and achieve the optimal posture of the whole vehicle.

[0017] The vehicle active suspension control method for flexible chassis extension connection described in the present invention is also characterized in that the vertical motion equation of the wheel in step 1 is as shown in equations (1) and (2):

[0018] (1)

[0019] (2)

[0020] In formula (1) and formula (2), , , are the state matrix, input matrix, and interference matrix of the i-th wheel suspension module, respectively. express The derivative of The state matrix representing the vertical motion of the body corner to which the i-th wheel suspension module is connected, is the output matrix of the i-th wheel suspension module, , , , , , , and There are 8 coefficient matrices respectively, and there are:

[0021] (3)

[0022] (4)

[0023] (5)

[0024] In formula (3), is the vertical velocity of the i-th wheel suspension module, is the vertical displacement of the i-th wheel suspension module, is the active suspension force output by the i-th wheel suspension module, is the vertical excitation of the road surface on the i-th wheel suspension module, is the vertical velocity of the body corner to which the i-th wheel suspension module is connected, is the vertical displacement of the body corner to which the i-th wheel suspension module is connected, is the force output from the i-th wheel suspension module to the vehicle body, and T represents the transposition;

[0025] In formula (4) and formula (5), is the unsprung mass of the i-th wheel suspension module, is the wheel tire stiffness of the i-th wheel suspension module, is the suspension spring stiffness of the i-th wheel suspension module, is the suspension damping coefficient of the i-th wheel suspension module.

[0026] Furthermore, the vertical, pitch and roll motion equations of the vehicle body in step 1 are as shown in equation (6):

[0027] (6)

[0028] In formula (6), is the state matrix of the vehicle body, express The coefficient matrix of express The coefficient matrix of is, n is the number of wheel suspension modules, and has:

[0029] (7)

[0030] In formula (7), is the vertical velocity of the body module, is the vertical displacement of the body module, is the roll angular velocity of the body module, is the roll angle of the body module, is the pitch angular velocity of the body module, is the pitch angle of the body module; is the mass of the body module, is the moment of inertia of the body module along the x-axis, is the moment of inertia of the body module along the y-axis, represents the vertical distance between the ith wheel suspension module and the xz plane where the center of mass of the vehicle body is located, represents the vertical distance between the i-th wheel suspension module and the xy plane where the center of mass of the vehicle body is located;

[0031] The correlation equation between the motion differential equations of the wheel suspension module and the body module in step 2 is shown in equation (8):

[0032] (8)

[0033] In formula (8), is the coefficient matrix of the association equation between the wheel suspension module and the body module, and has:

[0034] (9).

[0035] Furthermore, the vehicle dynamics model in step 3 is shown in formula (10):

[0036] (10)

[0037] The dynamic control model of the i-th active suspension system in step 3 is shown in formula (11):

[0038] (11)

[0039] In formula (11), represents the body state matrix of the dynamic control model of the i-th active suspension system, is the interference term of the i-th wheel suspension module itself and interference from all other wheel suspension modules The total interference term composed of k≠i, and there is:

[0040] (12)

[0041] In formula (12), represents the output matrix of the kth wheel suspension module, express The coefficient matrix of .

[0042] Furthermore, the objective function in step 4 is shown in formula (13):

[0043] (13)

[0044] In formula (13), represents the prediction step length, j is the current step number, is the state quantity of the body module at step j, is the desired body module state, represents the expected active force of the i-th active suspension system at the j-th step, represents the state of the body module at step j+1, is the state quantity of the i-th wheel suspension module in the j-th step, represents the total interference term of the i-th wheel suspension module at the j-th step, is the minimum value of the active force output by the active suspension actuator, The maximum value of the active force output by the active suspension actuator; , and They are three coefficient matrices respectively , and The three coefficient matrices after discretization are: is the time step.

[0045] Furthermore, the consensus algorithm in step 5 includes:

[0046] Step 5.1, initialize j = 0, calculate the output of the i-th wheel suspension module in the j-th step The acceleration generated at the center of mass of the vehicle ;

[0047] Step 5.2: For the kth wheel suspension module in the jth step, collect the output of the ith wheel suspension module in the jth step The acceleration generated at the center of mass of the vehicle body , ;

[0048] Step 5.3: For the k-th wheel suspension module in step j, Added to formula (11) In , ; Thus, the dynamic control model of the kth active suspension system after the jth step update is obtained;

[0049] Step 5.4: Solve the objective function to obtain the optimal active force output by the active suspension of the kth wheel suspension module in the jth step. ;

[0050] Step 5.5: Substituting into equation (1) and equation (2), we get the output of the kth wheel suspension module in step j+1: , and calculate the output of the kth wheel suspension module in the j+1th step by equation (14): The acceleration generated at the center of mass of the vehicle ;

[0051] (14)

[0052] In formula (14), represents the update coefficient, and ;

[0053] Step 5.6: If , then stop the calculation and output ; Otherwise, execute step 5.7, where represents the consensus threshold;

[0054] Step 5.7, order Assign to After that, if , then stop the calculation and output ; Otherwise, return to step 5.2 and execute in sequence, where: Indicates the maximum number of iterations allowed.

[0055] An electronic device of the present invention includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the vehicle active suspension control method, and the processor is configured to execute the program stored in the memory.

[0056] The present invention provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program executes the steps of the vehicle active suspension control method when the computer program is executed by a processor.

[0057] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0058] 1. In the control problem of the whole vehicle suspension system, the present invention decomposes the control problem of the original high-dimensional mathematical model of the active suspension of the whole vehicle into the control problem of the low-dimensional mathematical model of each wheel suspension system, reducing the consumption of computing resources and computing time in the control process. In the traditional whole vehicle active suspension control problem, when control algorithms such as LQR and MPC are used to uniformly control the suspension system of the whole vehicle, the model is too complex and the control algorithm calculation is time-consuming, which limits the application of active suspension in passenger cars to a certain extent. The distributed automobile suspension control algorithm proposed in the present invention decomposes the original whole vehicle suspension control problem into the control problem of a single wheel suspension model, reducing the hardware cost and the time cost of calculation, thereby realizing the application of active suspension in passenger cars.

[0059] 2. When designing a control strategy for active suspension, the present invention uses the dynamic response of the vehicle body as the state quantity that needs to be controlled by the model prediction control strategy of the single wheel suspension module controller. Since only the two-degree-of-freedom model of each suspension is controlled, the control effect of this distributed control strategy is worse than that of the integral suspension control strategy, but the model complexity and calculation speed are better than the integral control strategy. In order to improve the control effect of this control strategy on the whole vehicle, a consensus coordination algorithm is used to coordinate the active control force output by each active suspension actuator to achieve a better control effect for the whole vehicle.

[0060] 3. In order to coordinate the active control force output by each suspension system actuator to achieve the optimal control effect on the dynamic response of the whole vehicle, the present invention adopts the following control method in the control problem of the active suspension system: Figure 5The consensus coordination algorithm shown is used to coordinate the main power output of each suspension. In the traditional two-degree-of-freedom suspension system, only the dynamic response of the suspension connecting the corner of the vehicle body is considered when controlling the suspension. In this way, it is difficult to achieve optimal control of the dynamic response of the whole vehicle when controlling the whole vehicle. The present invention adopts a consensus coordination method to iteratively coordinate the output force of each wheel suspension system, and balances the contradiction between computational cost and control effect by controlling the number of iterations. The optimal control effect of the whole vehicle is achieved by adopting a control method similar to the two-degree-of-freedom suspension model.

[0061] 4. The present invention greatly reduces the cost of redesigning the vehicle model when the number of axles of the vehicle needs to be changed, shortens the time required for the design, and thus realizes a more convenient modification of the number of axles of the vehicle and the control of the suspension system. The present invention can establish a vehicle with different numbers of axles by adding or subtracting wheel suspension modules. Unlike the traditional vehicle model, which requires the whole vehicle to be remodeled, the present invention only modifies the vehicle model by changing the body model. At the same time, since only the body parameter items need to be changed when designing the controller after modifying the vehicle model, the difficulty of controller design is also reduced, the design process of the vehicle suspension system is simplified, the design cycle of the vehicle suspension system is shortened, and the vehicle's adaptability to different application scenarios and task requirements is enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a schematic diagram of a single wheel suspension module;

[0063] Figure 2 It is a schematic diagram of a body module of a multi-axle vehicle;

[0064] Figure 3 It is a schematic diagram of the body module of a two-axle vehicle;

[0065] Figure 4 This is the flow chart of the distributed control strategy for active suspension;

[0066] Figure 5 Flowchart for achieving consensus coordination between wheel suspension modules. DETAILED DESCRIPTION

[0067] In this embodiment, the following is established: Figure 1 The wheel suspension system model shown and Figure 2 The multi-axis vehicle body system model shown in Figure 1 is used, and a vehicle suspension distributed control system based on the model predictive control strategy is established. Figure 4As shown. In order to simplify the calculations in the modeling process, the following assumptions are adopted: the wheels are installed vertically to the ground and can only move vertically; only the vertical, pitch and roll movements of the vehicle body are considered; the vehicle body is a whole rigid body. During the operation of the vehicle, the active output force of the suspension acts directly on the vehicle body and wheels, thereby alleviating the vibration of the vehicle body and ensuring the smoothness of the vehicle during driving. Specifically, taking the seven-degree-of-freedom suspension system of the two-axle four-wheel vehicle model as an example, the suspension control method is carried out in the following steps:

[0068] Step 1: Establish a vehicle active suspension control method for flexible chassis extension connection. Taking the seven-degree-of-freedom suspension system of a two-axle four-wheel vehicle model as an example, build the wheel suspension model and body model of the seven-degree-of-freedom suspension system, respectively. Figure 1 and Figure 3 As shown, firstly, kinematic modeling is performed for the wheel suspension module and the body module, and their motion differential equations are established respectively. Then, the state space equations of motion are established based on their motion differential equations.

[0069] Step 1.1, for the multi-axle vehicle active suspension system of the whole vehicle, establish the motion differential equations of the wheel suspension module and the body module of the whole vehicle respectively;

[0070] Step 1.1.1, the differential equation of motion of the wheel suspension module of the whole vehicle, including: the vertical motion equation of the wheel, write the state space equation of the single wheel suspension module when it moves according to the differential equation of motion of the single wheel suspension module:

[0071] Differential equations of motion for a single wheel suspension module:

[0072] (1)

[0073] Output of a single wheel suspension module to the body module:

[0074] (2)

[0075] In formula (1) and formula (2), is the vertical acceleration of the i-th wheel suspension module, is the vertical velocity of the i-th wheel suspension module, is the vertical displacement of the i-th wheel suspension module, is the active suspension force output by the i-th wheel suspension module, is the vertical excitation of the road surface on the i-th wheel suspension module, is the vertical velocity of the body corner to which the i-th wheel suspension module is connected, is the vertical displacement of the car body corner connected to the i-th suspension system, is the force output from the i-th wheel suspension module to the vehicle body, is the unsprung mass of the i-th wheel suspension module, is the wheel tire stiffness of the i-th wheel suspension module, is the suspension spring stiffness of the i-th wheel suspension module, is the suspension damping coefficient of the i-th wheel suspension module.

[0076] The state space equation of the motion of a single wheel suspension module of the established distributed model of the vehicle suspension system is as follows:

[0077] (3)

[0078] In formula (3), , , are the state matrix, input matrix, and interference matrix of the i-th wheel suspension module, respectively. for The derivative of is the state matrix of the vertical motion of the body corner connected to the i-th wheel suspension module, is the output matrix of the i-th wheel suspension module, , , , , , , and There are 8 coefficient matrices respectively, and there are:

[0079] (4)

[0080] (5)

[0081] (6)

[0082] In formula (4), T represents transposition;

[0083] Step 1.1.2: The differential equations of motion of the body module include the vertical, pitch and roll motion equations of the body. Based on the differential equations of motion of the body module, write the state space equations of the body module when it is in motion:

[0084] The differential equation for the body motion is:

[0085] Vertical movement:

[0086] (7)

[0087] Rolling motion:

[0088] (8)

[0089] Pitch movement:

[0090] (9)

[0091] In formula (8) and formula (9): (10)

[0092] The state space equations of the body module motion of the established distributed model of the vehicle suspension system are as follows:

[0093] (11)

[0094] In formula (11), is the state matrix of the vehicle body, express The coefficient matrix of express The coefficient matrix of , and we have:

[0095] (12)

[0096] In formula (12), is the vertical velocity of the body module, is the vertical displacement of the body module, is the roll angular velocity of the body module, is the roll angle of the body module, is the pitch angular velocity of the body module, is the pitch angle of the body module; is the mass of the body module, is the moment of inertia of the body module along the x-axis, is the moment of inertia of the body module along the y-axis, represents the vertical distance between the ith wheel suspension module and the xz plane where the center of mass of the vehicle body is located, represents the vertical distance between the i-th wheel suspension module and the xy plane where the center of mass of the vehicle body is located;

[0097] Step 1.2: Establish the correlation equation between the differential equations of motion of the wheel suspension module and the body module, so as to obtain the force generated by the suspension system and output to the body, and the vertical displacement generated by the vertical, pitch and roll motion of the body and output to the single active suspension system. By assuming that the body is a rigid body, the vertical motion of the center of mass of the body is Vertical movement of the body corners connected to each wheel suspension module The relationship between them is:

[0098] (13)

[0099] In formula (13), is the coefficient matrix of the association equation between the wheel suspension module and the body module, and has:

[0100] (14)

[0101] Through the above steps, the dynamic modeling of the wheel suspension module and the body module has been completed, and the establishment of the correlation equation between the motion differential equations of the body module and the wheel suspension module has been completed, that is, the force output from the wheel suspension module to the body module The vertical displacement output from the body module to the wheel suspension module , through the above equations, the dynamic equation of the whole vehicle can be established;

[0102] Step 2: Based on the differential equations of motion of the wheel suspension module and the body module and the related equations, establish a vehicle dynamics model and build a dynamics control model of a single active suspension system; Based on the differential equations of motion of the wheel suspension module and the body module in step 1, and the related equations between the differential equations of motion of the body module and the wheel suspension module, build a vehicle dynamics model based on the wheel suspension module and the body module:

[0103] (15)

[0104] Since the vehicle dynamics model includes the body model and all wheel models, it cannot be directly used to design the control strategy of a single active suspension. Therefore, a dynamic model that can be used for the control of a single active suspension in a distributed suspension system is established for a single wheel suspension module and a body module. The specific form is as follows:

[0105] (16)

[0106] In formula (16), represents the body state matrix of the dynamic control model of the i-th active suspension system, is the interference term of the i-th wheel suspension module itself and interference from all other wheel suspension modules The total interference term composed of k≠i, and there is:

[0107] (17)

[0108] In formula (17), represents the output matrix of the kth wheel suspension module, express The coefficient matrix of ;

[0109] Step 3: Based on the dynamic control model of a single wheel suspension module, taking the optimal posture of the whole vehicle as the objective function and the dynamic response of the whole vehicle body as the control state quantity, the model predictive control strategy is used to control any single active suspension system, thereby obtaining the active control force output by the single active suspension system. The objective function of the model predictive control strategy is shown in formula (18):

[0110] (18)

[0111] In formula (18), represents the prediction step length, j is the current step number, is the state quantity of the body module at step j, is the desired body module state, represents the expected active force of the i-th active suspension system at the j-th step, represents the state of the body module at step j+1, is the state quantity of the i-th wheel suspension module in the j-th step, represents the total interference term of the i-th wheel suspension module at the j-th step, is the minimum value of the active force output by the active suspension actuator, The maximum value of the active force output by the active suspension actuator; , and are the coefficient matrices in formula (11) , and The three coefficient matrices after discretization are: The active suspension force required to control each suspension is obtained through the above control strategy.

[0112] Step 4. Since only a single wheel suspension model is controlled in step 3, to achieve optimal control of the vehicle's posture, it is necessary to design a consensus coordination algorithm between control strategies for different wheel suspension models. The influence of each wheel suspension module on the vertical acceleration of the vehicle's center of mass and the body's roll and pitch acceleration is used as the consensus quantity between the wheel suspension modules. The consensus algorithm is used to adjust the active control force output by each active suspension system, and the adjusted active control force is obtained and output, thereby achieving optimal control of the active suspension system of the multi-axle vehicle to achieve the optimal posture of the vehicle. Through the consensus coordination algorithm, the active force output by each active suspension system is optimized to achieve optimal control of the vehicle. The execution logic of the designed consensus coordination algorithm is as follows: Figure 5 As shown, the specific iterative process is as follows:

[0113] Step 4.1. Initialize j = 0 and calculate the output of the i-th wheel suspension module in the j-th step. The acceleration generated at the center of mass of the vehicle ;

[0114] Step 4.2: For the kth wheel suspension module in the jth step, collect the output of the ith wheel suspension module in the jth step The acceleration generated at the center of mass of the vehicle , ;

[0115] Step 4.3: For the k-th wheel suspension module in step j, Added to formula (16) Thus, the dynamic control model of the kth active suspension system after the jth step update is obtained, where , ;

[0116] Step 4.4: Solve the objective function to obtain the optimal active force output by the active suspension of the k-th wheel suspension module in the j-th step. ;

[0117] Step 4.5: Substitute into equation (3) to obtain the output of the kth wheel suspension module in the j+1th step: , and calculate the output of the kth wheel suspension module in the j+1th step through equation (19): The acceleration generated at the center of mass of the vehicle ;

[0118] (19)

[0119] In formula (19), represents the update coefficient, and ;

[0120] Step 4.6: If , then stop the calculation and output ; Otherwise, execute step 4.7, where represents the consensus threshold;

[0121] Step 4.7, order Assign to After that, if , then stop the calculation and output ; Otherwise, return to step 4.2 and execute in sequence, where: Indicates the maximum number of iterations allowed.

[0122] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0123] In this embodiment, a computer-readable storage medium stores a computer program on the computer-readable storage medium, and the computer program executes the steps of the above method when executed by a processor.

[0124] In summary, the present invention reduces the requirements on the computing power of the hardware computing unit on the basis of ensuring the active suspension function, and realizes the application of active suspension on existing passenger cars at a relatively low cost on the basis of ensuring the basic functions of the active suspension. And because the distributed suspension has the characteristics of modular design and an expandable structure, when increasing or decreasing the number of vehicle axles, it is only necessary to modify the body module in the distributed suspension model without having to reconstruct the model of the entire vehicle, which greatly improves the adaptability of the vehicle to different scenarios and task requirements. On the basis of the suspension, the driving, braking and steering functions of the chassis of the entire vehicle can be incorporated into the design of the wheel module to form a fully functional flexible chassis for the vehicle.

Claims

1. A vehicle active suspension control method for flexible chassis extension connection, characterized in that: The steps are as follows: Step 1: for a multi-axle vehicle active suspension system of a whole vehicle, respectively establish the motion differential equations of the wheel suspension module and the body module of the whole vehicle; wherein the motion differential equation of the wheel suspension module of the whole vehicle includes: the vertical motion equation of the wheel; The motion differential equations of the vehicle body module include: the vertical, pitch and roll motion equations of the vehicle body; Step 2: Establish the correlation equation between the differential equations of motion of the wheel suspension module and the body module, so as to obtain the force generated by the suspension system and output to the body, and the vertical displacement generated by the vertical, pitch and roll motions of the body and output to the single active suspension system; Step 3: Based on the motion differential equations and correlation equations of the wheel suspension module and the body module, a vehicle dynamics model is established, and a dynamics control model of a single active suspension system is constructed; The vehicle dynamics model includes: a dynamics model of the vehicle body and all active suspension systems; The dynamics control model of the single active suspension system includes: a dynamics model of a body module and a dynamics control model of a single wheel suspension module; Step 4: Based on the dynamic control model of a single wheel suspension module, taking the optimal posture of the whole vehicle as the objective function and the dynamic response of the whole vehicle body as the control state quantity, a model predictive control strategy is adopted to control any single active suspension system, thereby obtaining the active control force output by the single active suspension system; Step 5: Use the influence of each wheel suspension module on the vertical acceleration of the vehicle center of mass and the roll and pitch angle acceleration of the vehicle body as the consensus quantity between the wheel suspension modules, and use the consensus algorithm to adjust the active control force output by each active suspension system, obtain the adjusted active control force and output it, so as to achieve the optimal control of the active suspension system of the multi-axle vehicle and achieve the optimal posture of the whole vehicle.

2. A vehicle active suspension control method for flexible chassis extension connection according to claim 1, characterized in that: The vertical motion equation of the wheel in step 1 is shown in equations (1) and (2): (1) (2) In formula (1) and formula (2), , , are the state matrix, input matrix, and interference matrix of the i-th wheel suspension module, respectively. express The derivative of The state matrix representing the vertical motion of the body corner to which the i-th wheel suspension module is connected, is the output matrix of the i-th wheel suspension module, , , , , , , and There are 8 coefficient matrices respectively, and there are: (3) (4) (5) In formula (3), is the vertical velocity of the i-th wheel suspension module, is the vertical displacement of the i-th wheel suspension module, is the active suspension force output by the i-th wheel suspension module, is the vertical excitation of the road surface on the i-th wheel suspension module, is the vertical velocity of the body corner to which the i-th wheel suspension module is connected, is the vertical displacement of the body corner to which the i-th wheel suspension module is connected, is the force output from the i-th wheel suspension module to the vehicle body, and T represents the transposition; In formula (4) and formula (5), is the unsprung mass of the i-th wheel suspension module, is the wheel tire stiffness of the i-th wheel suspension module, is the suspension spring stiffness of the i-th wheel suspension module, is the suspension damping coefficient of the i-th wheel suspension module.

3. The vehicle active suspension control method for flexible chassis extension connection according to claim 2, characterized in that: The vertical, pitch and roll motion equations of the vehicle body in step 1 are shown in equation (6): (6) In formula (6), is the state matrix of the vehicle body, express The coefficient matrix of express The coefficient matrix of is, n is the number of wheel suspension modules, and has: (7) In formula (7), is the vertical velocity of the body module, is the vertical displacement of the body module, is the roll angular velocity of the body module, is the roll angle of the body module, is the pitch angular velocity of the body module, is the pitch angle of the body module; is the mass of the body module, is the moment of inertia of the body module along the x-axis, is the moment of inertia of the body module along the y-axis, represents the vertical distance between the ith wheel suspension module and the xz plane where the center of mass of the vehicle body is located, represents the vertical distance between the i-th wheel suspension module and the xy plane where the center of mass of the vehicle body is located; The correlation equation between the motion differential equations of the wheel suspension module and the body module in step 2 is shown in equation (8): (8) In formula (8), is the coefficient matrix of the association equation between the wheel suspension module and the body module, and has: (9)。 4. The vehicle active suspension control method for flexible chassis extension connection according to claim 3, characterized in that: The vehicle dynamics model in step 3 is shown in formula (10): (10) The dynamic control model of the i-th active suspension system in step 3 is shown in formula (11): (11) In formula (11), represents the body state matrix of the dynamic control model of the i-th active suspension system, is the interference term of the i-th wheel suspension module itself and interference from all other wheel suspension modules The total interference term composed of k≠i, and there is: (12) In formula (12), represents the output matrix of the kth wheel suspension module, express The coefficient matrix of .

5. The vehicle active suspension control method for flexible chassis extension connection according to claim 4, characterized in that: The objective function in step 4 is shown in formula (13): (13) In formula (13), represents the prediction step length, j is the current step number, is the state quantity of the body module at step j, is the desired body module state, represents the expected active force of the i-th active suspension system at the j-th step, represents the state of the body module at step j+1, is the state quantity of the i-th wheel suspension module in the j-th step, represents the total interference term of the i-th wheel suspension module at the j-th step, is the minimum value of the active force output by the active suspension actuator, The maximum value of the active force output by the active suspension actuator; , and They are three coefficient matrices respectively , and The three coefficient matrices after discretization are: is the time step.

6. A vehicle active suspension control method for flexible chassis extension connection according to claim 5, characterized in that: The consensus algorithm in step 5 includes: Step 5.1, initialize j = 0, calculate the output of the i-th wheel suspension module in the j-th step The acceleration generated at the center of mass of the vehicle ; Step 5.2: For the kth wheel suspension module in the jth step, collect the output of the ith wheel suspension module in the jth step The acceleration generated at the center of mass of the vehicle body , ; Step 5.3: For the k-th wheel suspension module in step j, Added to formula (11) In , ; Thus, the dynamic control model of the kth active suspension system after the jth step update is obtained; Step 5.4: Solve the objective function to obtain the optimal active force output by the active suspension of the kth wheel suspension module in the jth step. ; Step 5.5: Substituting into equation (1) and equation (2), we get the output of the kth wheel suspension module in step j+1: , and calculate the output of the kth wheel suspension module in the j+1th step by equation (14): The acceleration generated at the center of mass of the vehicle ; (14) In formula (14), represents the update coefficient, and ; Step 5.6: If , then stop the calculation and output ; Otherwise, execute step 5.7, where, represents the consensus threshold; Step 5.7, command Assign to After that, if , then stop the calculation and output ; Otherwise, return to step 5.2 and execute in sequence, where: Indicates the maximum number of iterations allowed.

7. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the vehicle active suspension control method according to any one of claims 1 to 6, and the processor is configured to execute the program stored in the memory.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the vehicle active suspension control method according to any one of claims 1 to 6 are executed.

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