An electronically controlled air suspension pitch control system and method based on MPC technology

Abstract

The present invention discloses an electronically controlled air suspension pitch control system based on MPC technology. The system comprises: a sensor module for collecting vehicle status information and a vehicle pitch dynamics model for predicting the vehicle's pitch motion; an ECAS control unit comprising a model predictive controller for calculating and outputting control signals in real time based on the vehicle status information and the vehicle pitch dynamics model; and an actuator comprising an air spring stiffness regulating valve and a damping valve controller. The present invention also discloses an electronically controlled air suspension pitch control method based on MPC technology. Compared to existing technologies, the present invention addresses the issues of slow response speed and poor control accuracy in pitch control of existing electronically controlled air suspension systems.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile electronic control technology, and in particular to an electronically controlled air suspension pitch control system and method based on MPC technology. Background Art

[0002] The Electronically Controlled Air Suspension System (ECAS) is a key system in modern passenger cars, designed to improve ride comfort and vehicle stability. Pitch control is a key function of ECAS, designed to reduce vehicle pitch motion during acceleration and braking, thereby improving ride comfort and vehicle handling.

[0003] Existing pitch control algorithms mostly use traditional PID control or fuzzy control. These methods have certain limitations when dealing with nonlinear and time-varying systems, resulting in slow response speed and poor control accuracy of the electronically controlled air suspension system in pitch control. Summary of the Invention

[0004] The purpose of the present invention is to provide an electronically controlled air suspension pitch control system and method based on MPC technology to solve the problems of slow response speed and poor control accuracy in pitch control of existing electronically controlled air suspension systems.

[0005] In order to achieve the above objectives, the present invention adopts the following technical solutions: On the one hand, the present invention discloses an electronically controlled air suspension pitch control system based on MPC technology, comprising:

[0006] Sensor module, which is used to collect vehicle status information,

[0007] A vehicle pitch dynamics model, which is used to predict the pitch motion of the vehicle. The vehicle pitch dynamics model is a nonlinear time-varying model;

[0008] The ECAS control unit includes a model predictive controller, which is used to calculate and output control signals in real time based on vehicle state information and a vehicle pitch dynamics model;

[0009] The actuator includes an air spring stiffness regulating valve and a damping valve controller. The air spring stiffness regulating valve is used to adjust the stiffness of the air spring, and the damping valve controller is used to control the opening of the damping valve.

[0010] On the other hand, the present invention also discloses a pitch control method of an electronically controlled air suspension based on MPC technology, comprising the following steps:

[0011] S1. Data acquisition: The sensor module collects vehicle status information, including vehicle speed, suspension longitudinal acceleration, pitch angle, and suspension displacement distance;

[0012] S2. Vehicle State Prediction: The ECAS control unit uses the model predictive controller to calculate and predict the vehicle's pitch angle and pitch rate for the next N steps based on the acquired vehicle state information and the vehicle pitch dynamics model. The ECAS control unit obtains vehicle state information collected by the sensor module via CAN bus communication to ensure information collection quality.

[0013] S3. Constructing the optimization problem: The objective function in the model predictive controller includes the pitch angle deviation F c , pitch angular velocity deviation F s And the control input change K b The objective function value is calculated by taking the weighted sum of the values ​​of the damping valve, the upper limit of the air pump pressure, and the corresponding speed of the actuator.

[0014] S4, numerical optimization solution: Use numerical optimization algorithms to solve the optimization problem and output the optimal control sequence for the vehicle in the next N steps;

[0015] S5, rolling optimization objective function: execute the first control instruction in the optimal control sequence, update the electronically controlled air suspension pitch control system, and enter the next cycle. The execution cycle is 10-50ms;

[0016] S6, signal output: output control signal to the actuator.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. In the present invention, a model predictive controller is embedded in the ECAS control unit, and the MPC algorithm is used to calculate and output control signals in real time. By optimizing the objective function, the pitch angle and pitch angular velocity are minimized, and the stiffness and damping of the suspension system are adjusted in real time according to the vehicle status and road condition information.

[0019] 2. In the present invention, through model predictive control, the pitch motion of the vehicle can be predicted and compensated more accurately, thereby improving control accuracy. Moreover, the nonlinear time-varying model can adapt to different road conditions and driving conditions, thereby improving the robustness of the system.

[0020] 3. In the present invention, a rolling optimization strategy is adopted to update the control input in real time to adapt to the dynamic changes of the system and improve the system response speed and dynamic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a system architecture diagram of an electronically controlled air suspension pitch control system based on MPC technology.

[0023] Figure 2 The figure is a flow chart of a pitch control method of an electronically controlled air suspension based on MPC technology.

[0024] Figure 3 This is a modeling and simulation curve diagram of an electronically controlled air suspension pitch control method based on MPC technology. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0027] Example 1

[0028] See also Figure 1-3 On the one hand, the present invention discloses an electronically controlled air suspension pitch control system based on MPC technology, comprising:

[0029] Sensor module, which is used to collect vehicle status information,

[0030] A vehicle pitch dynamics model, which is used to predict the pitch motion of the vehicle. The vehicle pitch dynamics model is a nonlinear time-varying model;

[0031] The ECAS control unit includes a model predictive controller, which is used to calculate and output control signals in real time based on vehicle state information and a vehicle pitch dynamics model;

[0032] The actuator includes an air spring stiffness regulating valve and a damping valve controller. The air spring stiffness regulating valve is used to adjust the stiffness of the air spring, and the damping valve controller is used to control the opening of the damping valve.

[0033] On the other hand, the present invention also discloses a pitch control method of an electronically controlled air suspension based on MPC technology, comprising the following steps:

[0034] S1. Data acquisition: The sensor module collects vehicle status information, including vehicle speed, suspension longitudinal acceleration, pitch angle, and suspension displacement distance;

[0035] S2. Vehicle State Prediction: The ECAS control unit calculates and predicts the vehicle's pitch angle and pitch rate for the next N steps based on the acquired vehicle state information and the vehicle pitch dynamics model using a model predictive controller. The ECAS control unit obtains vehicle state information collected by the sensor module via CAN bus communication to ensure information collection quality.

[0036] S3. Constructing the optimization problem: The objective function in the model predictive controller includes the pitch angle deviation F c , pitch angular velocity deviation F s And the control input change K b The objective function value is calculated by taking the weighted sum of the values ​​of the damping valve, the upper limit of the air pump pressure, and the corresponding speed of the actuator.

[0037] S4, numerical optimization solution: Use numerical optimization algorithms to solve the optimization problem and output the optimal control sequence for the vehicle in the next N steps;

[0038] S5, rolling optimization objective function: execute the first control instruction in the optimal control sequence, update the electronically controlled air suspension pitch control system, and enter the next cycle. The execution cycle is 10-50ms;

[0039] S6, signal output: output control signal to the actuator.

[0040] By establishing a vehicle pitch dynamics model and adjusting the suspension system's stiffness and damping in real time, this method effectively reduces vehicle pitch motion during acceleration and braking, improving ride comfort and vehicle handling. A model predictive controller (MPC) is used to enhance the ECAS's response speed and control accuracy in pitch control. This electronically controlled air suspension pitch control method is highly adaptable to diverse road and driving conditions, demonstrating excellent robustness and versatility.

[0041] Working principle: A model predictive controller is embedded in the ECAS control unit, and the MPC algorithm is used to calculate and output control signals in real time. By optimizing the objective function, the pitch angle and pitch angular velocity are minimized, and the stiffness and damping of the suspension system are adjusted in real time according to the vehicle status (such as speed, acceleration, pitch angle, etc.) and road conditions.

[0042] A vehicle pitch dynamics model is established based on parameters such as vehicle mass, suspension stiffness, and damping coefficients. Experimental data is used to identify the model parameters, and a nonlinear time-varying model is developed based on the vehicle's dynamic characteristics under varying road and driving conditions. Model predictive control enables more accurate prediction and compensation of vehicle pitch motion, improving control precision. The nonlinear time-varying model adapts to varying road and driving conditions, enhancing system robustness. A rolling optimization strategy is employed to update control inputs in real time to adapt to system dynamics, improving system response speed and dynamic performance.

[0043] Example 2

[0044] This embodiment further provides the following improved technical solutions based on the above embodiment: In step S3, the mathematical expression of the objective function is as follows:

[0045]

[0046] Among them, N p is the prediction time domain, N c For the control time domain, ω1, ω2, and ω3 are weight coefficients, and ω3>ω2>ω1. Design the prediction time domain and control time domain, and determine the optimization objective function and constraints.

[0047] When optimizing the objective function value, priority is given to limiting the drastic changes in the control input and the speed of change of the pitch angle. This can slightly sacrifice the pitch angle control accuracy, allowing the electronically controlled air suspension to avoid frequent and large adjustments to the pitch angle.

[0048] Specifically, in step S3, the ratio of the weight coefficients ω1:ω2:ω3 is 2:3:4. The weight coefficients can be flexibly adjusted after the effectiveness and performance of the algorithm are verified through actual vehicle experiments.

[0049] Example 3

[0050] This embodiment further makes the following improved technical solutions based on the above embodiments: Specifically, in step S4, ρ is minimized by a quadratic programming (QP) solver, and the control input sequence with the minimum objective function is output to obtain the optimal control input.

[0051] Example 4

[0052] This embodiment further provides the following improved technical solutions based on the above embodiment: Specifically, in step S6, the control signal includes a suspension stiffness instruction and a damping instruction.

[0053] The air spring rate and damping valve opening are adjusted based on the control signal from the ECAS control unit to suppress pitch angle changes. The air spring rate is adjusted by adjusting the air pressure in the air spring through the air spring rate adjustment valve.

[0054] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A pitch control method for an electronically controlled air suspension based on MPC technology, characterized in that: The following steps are involved: S1. Data acquisition: The sensor module collects vehicle status information; S2. Vehicle state prediction: The ECAS control unit calculates and predicts the vehicle's pitch angle and pitch angular velocity for the next N steps using a model predictive controller based on the acquired vehicle state information and the vehicle pitch dynamics model. S3. Constructing the optimization problem: The objective function in the model predictive controller includes the pitch angle deviation , pitch angular velocity deviation and control input variation The objective function value is calculated by taking the weighted sum of the values ​​of the damping valve, the upper limit of the air pump pressure, and the corresponding speed of the actuator. S4, numerical optimization solution: Use numerical optimization algorithms to solve the optimization problem and output the optimal control sequence for the vehicle in the next N steps; S5, rolling optimization objective function: execute the first control instruction in the optimal control sequence, update the electronically controlled air suspension pitch control system, and enter the next cycle. The execution cycle is 10-50ms; S6, signal output: output control signal to the actuator.

2. The pitch control method of an electronically controlled air suspension based on MPC technology according to claim 1, characterized in that: In step S3, the mathematical expression of the objective function is as follows: in, For the prediction time domain, To control the time domain, 、 、 is the weight coefficient, and .

3. The pitch control method of an electronically controlled air suspension based on MPC technology according to claim 2, characterized in that: In step S3, the weight coefficient : The ratio is 2:3:

4.

4. The pitch control method of an electronically controlled air suspension based on MPC technology according to claim 2, characterized in that: In step S4, the quadratic programming solver is used to minimize , output the control input sequence with the minimum objective function.

5. The pitch control method of an electronically controlled air suspension based on MPC technology according to claim 1, characterized in that: The vehicle status information includes vehicle speed, suspension longitudinal acceleration, pitch angle, and suspension displacement distance.

6. The pitch control method of an electronically controlled air suspension based on MPC technology according to claim 1, characterized in that: In step S2, the ECAS control unit obtains the vehicle status information collected by the sensor module through CAN bus communication.

7. The pitch control method of an electronically controlled air suspension based on MPC technology according to claim 1, characterized in that: In step S6 , the control signal includes a suspension stiffness command and a damping command.

8. An electronically controlled air suspension pitch control system based on MPC technology, adopting the electronically controlled air suspension pitch control method based on MPC technology according to any one of claims 1 to 7, characterized in that: include: Sensor module, which is used to collect vehicle status information, A vehicle pitch dynamics model, which is used to predict the pitch motion of the vehicle, wherein the vehicle pitch dynamics model is a nonlinear time-varying model; The ECAS control unit includes a model predictive controller for calculating and outputting a control signal in real time based on vehicle state information and a vehicle pitch dynamics model; The actuator comprises an air spring stiffness regulating valve and a damping valve controller, wherein the air spring stiffness regulating valve is used to regulate the stiffness of the air spring, and the damping valve controller is used to control the opening of the damping valve.

Images