Fuzzy PID Control Strategy And Experimental Study Of Air Suspension Self - Tuning

Along with the continuous development of auto industry, people is becoming more and more demanding to the safety, stability and comfort of a car. pneumatic suspension system, because of its good buffer and damping performance,it get the favor of major automobile manufacturers, and become the researchers’focus in the related field. As the connection of car body and wheel in the middle of the system, suspension determines the ride performance, ride comfort and handling stability of a car, so the control strategy research of pneumatic suspension possesses a certain theoretical and practical significance. Pneumatic suspension, treated as the research object of this paper, is made a in-depth study of control strategy and its controller and the control strategy simulation test.First of all, based on the theory analysis on the characteristics of pneumatic suspension, combined with the theoretical analysis, by using the method of characteristic test to get the stiffness characteristics of the air spring, fitting out its stiffness characteristic curve, analyzed its stiffness characteristics.Secondly, established the mathematical model of1/4vehicle pneumatic suspension, its physical model is set up in Matlab/Simulink simulation system and do the simulation research. To do the comparison research, established the simulation model of passive suspension; In addition, the suspension performance evaluation index is introduced, it made the bedding for analysis of the results of simulation and the test of suspension.Thirdly, based on the theory of PID control and self-tuning fuzzy PID control, designed the PID controller and self-tuning fuzzy PID controller, established simulation model of the pneumatic suspension using the PID control and fuzzy self-tuning PID control, and do the simulation and analysis research. Comparison results show that the proposed PID control and self-tuning fuzzy PID control effectively improved the performance of suspension.Finally, according to the theoretical analysis of the pneumatic suspension, the testing program is proposed and the test-bed of pneumatic suspension system is set up, the vertical vibration acceleration of sprung mass and suspension dynamic deflection is selected as the performance evaluation index of the suspension, using the four types of pressure working conditions of gasbag is used to simulate the control strategy of pneumatic suspension, through controlling the open and close of solenoid valve to adjust the pressure to change the stiffness and the height of the pneumatic suspension, The data of vertical vibration acceleration and displacement from the four types of pressure working conditions for pneumatic suspension test-bed system is collected and analyzed to evaluate the advantages and disadvantages of the suspension performance. Experimental data analysis results show that, under the four types of pressure working conditions, the weighted root mean square value and the peak value of the vertical vibration acceleration of sprung mass and suspension dynamic deflection of the test-bed and the value after exerting control into simulation are nearly consistent.