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CN-116533698-B - Automobile active suspension control method based on self-adaptive inversion quick terminal sliding mode

CN116533698BCN 116533698 BCN116533698 BCN 116533698BCN-116533698-B

Abstract

The invention belongs to the field of automobile active suspension control, and discloses an automobile active suspension control method based on a self-adaptive inversion quick terminal sliding mode, which comprises the following steps of firstly, establishing a nonlinear semi-active suspension model; the method comprises the steps of determining ideal vertical and pitching motion tracks of a vehicle, establishing a nonsingular integral sliding mode surface, simultaneously establishing a state space model based on the selected sliding mode surface, designing a virtual control force control law of vertical motion of the vehicle based on an inversion sliding mode control method, designing a self-adaptive control law of a sliding mode robust item based on a self-adaptive control method, repeating the steps four to five, designing a virtual control moment control law of pitching motion of the vehicle, and calculating output forces of left and right active suspension actuators. The invention can effectively solve the problems of nonlinearity and uncertainty of the control model, and enables the vertical movement and pitch angle movement of the vehicle body to reach a stable state in a short time.

Inventors

  • LI DANYANG
  • ZHAO YOUQUN
  • YU ZHIHAO
  • LIN FEN

Assignees

  • 南京航空航天大学

Dates

Publication Date
20260508
Application Date
20230510

Claims (6)

  1. 1. The automobile active suspension control method based on the self-adaptive inversion quick terminal sliding mode is characterized by comprising the following steps of: step 1, establishing a nonlinear semi-active suspension model dynamic equation, and defining state variables ; For the vertical displacement of the vehicle, Is the pitch angle of the vehicle; Step 2, determining ideal vertical and pitching motion tracks of the vehicle 、 ; Step 3, establishing a nonsingular integral sliding mode surface, and simultaneously converting a system state space model based on state variables into a state space model based on a selected sliding mode surface, wherein in the step 3: Definition of tracking error , The non-singular integral slip-plane expression is: Wherein: And Is a slip form surface, parameters , ; The parameters are slip form surface parameters, which are positive scalar quantities; Variables in the state space model based on the selected sliding mode surface The expression of (2) is: ; step 4, designing a virtual control force control law of the vertical motion of the vehicle based on an inversion sliding mode control method, and designing the virtual control force control law of the vertical motion of the vehicle by using a robust term, wherein the robust term is , Is that Is used as a function of the sign of (c), In order to virtually control the error of the process, Is the sprung mass of the vehicle; step 5, designing a robust item self-adaptive control law based on the self-adaptive control method Instead of the robust term in step4 Simultaneously updating the virtual control force control law of the vehicle vertical movement designed in the step 4; step 6, repeating the step 4-5, and designing a virtual control moment control law of the pitching motion of the vehicle ; Step 7, calculating the output force of the front and rear active suspension actuators 、 。
  2. 2. The method for controlling an active suspension of an automobile based on an adaptive inversion fast terminal sliding mode according to claim 1, wherein in step 1, The nonlinear semi-active suspension model dynamic equation is: In the form of an uncertainty of the sprung mass, For the second time of the derivation, Virtual control force for the vertical movement of the vehicle, 、 Spring elastic force and damping force of the front active suspension, 、 For the spring elastic force and damping force of the rear active suspension, The disturbance force is unknown for the vertical movement of the vehicle, For the moment of inertia of the pitch motion of the vehicle, In order for the moment of inertia to be an uncertainty, The moment is virtually controlled for the pitching motion of the vehicle, 、 The distance from the center of the front and rear active suspension to the center of the sprung mass of the vehicle, Unknown disturbance moment for pitching motion; And is also provided with 、 And 、 The expression of (2) is as follows: Wherein, the 、 For the forward and rearward displacement of the unsprung mass, For the purpose of one-time derivation, 、 Is the rigidity coefficient of the front and the back elastic force, 、 The damping coefficient is the damping coefficient of the front damping force and the rear damping force; assuming that the output forces of the front and rear actuators are respectively 、 Virtual control force for vertical movement of vehicle Virtual control moment with pitching motion of vehicle : The dynamic equation of the nonlinear semi-vehicle active suspension model is rewritten as: Wherein the variables are Variable(s) Variable(s) Variable(s) 。
  3. 3. The method for controlling an active suspension of an automobile based on an adaptive inversion fast terminal sliding mode as claimed in claim 2, wherein in step 3: And has the following steps: thus: Based on selected slide surfaces And Constructing a three-order state space model, wherein state variables comprise , , , , , Wherein s 2 and Respectively is a slip form surface Is used to determine the first and second derivatives of (a), And Respectively is a slip form surface The differential equation of the third state space model is: 。
  4. 4. The method for controlling an active suspension of an automobile based on an adaptive inversion fast terminal sliding mode as claimed in claim 3, wherein in step 4: Defining a coordinate change: Wherein the method comprises the steps of , Virtual control quantity for the process; virtual control error for the process; Step 4.1, designing virtual control quantity : According to the change of coordinates Introducing a first sub-Lyapunov function Design of Parameters (parameters) Then: This indicates that as long as , Will be asymptotically stable; step 4.2, designing virtual control quantity : According to the change of coordinates Introducing a second sub-Lyapunov function Design of Parameters (parameters) Then: This indicates that as long as , And (3) with Will be asymptotically stable; Step 4.3, designing a virtual control force control law of vehicle vertical movement Introducing a third sub-Lyapunov function The following steps are: Design of Wherein the robust term And parameters of , ; Thus: This indicates 、 And Will converge to 0 within a finite time.
  5. 5. The method for controlling an active suspension of an automobile based on an adaptive inversion fast terminal sliding mode as claimed in claim 4, wherein in step 6: The following coordinate changes are defined: wherein the design process virtually controls the volume , ; Design of virtual control moment control law for pitching motion of vehicle The expression is: wherein the sliding mode robust term self-adaptive control law The method comprises the following steps: Wherein the method comprises the steps of Adaptive control law parameters 。
  6. 6. The method for controlling an active suspension of an automobile based on an adaptive inversion fast terminal sliding mode according to claim 5, wherein in step 7: output force of front and rear active suspension actuators 、 The following are provided: 。

Description

Automobile active suspension control method based on self-adaptive inversion quick terminal sliding mode Technical Field The invention relates to the field of automobile active suspension control, in particular to an automobile active suspension control method based on a self-adaptive inversion quick terminal sliding mode. Background The suspension is used as a connecting device between an automobile body and wheels, can bear the weight of the automobile body, and dampens vibration transmitted to the automobile body from road surface excitation, so that the suspension is a key system for influencing riding comfort and safety of the automobile. The active suspension is based on the traditional passive suspension, and an actuator parallel to the shock absorber, such as a motor, a hydraulic actuator, a hydraulic-pneumatic hybrid actuator and the like, is arranged between the vehicle body and the wheels. The active suspension system can obtain the optimal control force output by each actuator under different driving working conditions by utilizing a designed control algorithm according to the real-time feedback signals of the sensors, so that the suspension performance is improved, and therefore, the development of an excellent control algorithm is always a hot spot for the research of the active suspension of the automobile. In recent years, researchers at home and abroad research various active suspension control methods including full-state feedback control, optimal control, robust control, sliding mode control and the like, and various control methods have advantages and disadvantages, wherein the research difficulty is that the uncertainty of nonlinearity of an active suspension control model and the uncertainty of part of system parameters changing along with time, specifically, the uncertainty of sensor precision errors, the nonlinearity of suspension stiffness and shock absorber damping, the uncertainty of sprung mass and external interference and the like, and the factors influence the accuracy and the robustness of active suspension control. Accordingly, the active suspension control method based on the self-adaptive inversion quick terminal sliding mode is provided, and the running smoothness of the automobile can be effectively improved. Disclosure of Invention The invention aims to solve the technical problems that under the condition that a control model has nonlinearity and uncertainty changing along with time, the control law of the control force of the active suspension actuator is designed, so that the vertical movement and pitching movement of a vehicle body can still better isolate the influence caused by road surface excitation, and the system can reach a stable state in a short time. In order to achieve the above purpose, the invention adopts the following technical scheme: an automobile active suspension control method based on a self-adaptive inversion quick terminal sliding mode comprises the following steps: Step 1, establishing a nonlinear semi-vehicle active suspension model dynamic equation; Step 2, determining ideal vertical and pitching motion tracks x 1d、x3d of the vehicle, and particularly, setting ideal vertical acceleration and pitching motion angular acceleration of the vehicle to be zero; step 3, establishing a nonsingular integral sliding mode surface, and simultaneously converting a system state space model based on state variables into a state space model based on a selected sliding mode surface; step 4, designing a virtual control force control law of the vertical motion of the vehicle based on an inversion sliding mode control method; Step 5, a robust item self-adaptive control law u as1 is designed based on a self-adaptive control method to replace u s1 in step 4, and meanwhile, the vehicle vertical motion virtual control force control law designed in step 4 is updated; step 6, repeating the step 4-5, and designing a virtual control moment control law of the pitching motion of the vehicle And 7, calculating the output force u 1、u2 of the front and rear active suspension actuators. Preferably, in step 1, The nonlinear semi-active suspension model dynamic equation is: m is the sprung mass of the vehicle, Δm is the uncertainty of the sprung mass, z c is the vertical displacement of the vehicle, For secondary derivation, u z is the virtual control force of the vertical motion of the vehicle, F kf、Fkr is the spring elastic force and damping force of the front active suspension, F cf、Fcr is the spring elastic force and damping force of the rear active suspension, deltaF is the unknown disturbance force of the vertical motion of the vehicle, I is the moment of inertia of the pitching motion of the vehicle, deltaI is the uncertain part of the moment of inertia,Is the pitch angle of the vehicle,A, b are distances from the centers of the front active suspension and the rear active suspension to the center of sprung mass of the vehicle respectively, and DeltaM is unknown disturba