Control System Design Of Brake Test Bench Constant-torque Braking Based On Fuzzy PID Control

Constant-torque braking test of brake test bench is an important test requirement. This paper took the brake test bench as the research background which is commonly used in automobile manufacturing industry. This paper took the constant-torque brake control system as the research object, it analyzed the control characteristics and the implementation of key parts, discussed the design of constant-torque brake control system.Constant-torque braking test relied a lot on the industrial control computer’s operating system real-time, Windows XP operating system can not provide the real-time requirements for brake test. Based on the Windows XP operating system, with the installation of the plug-RTX design, the real-time of Windows XP operating system was greatly enhanced. By the use of RTX interrupt management mechanism, the operating system can directly access to I/O hardware port, by providing shared memory the operating system can accomplish the quick interactivity between the RTX real-time process and Win32 non-real-time processes. The Industrial control computer operating system can achieve real-time by the design of Windows XP + RTX.Constant-torque braking control took the PID controller which is widely applied in the industrial control, but the parameters of conventional PID controller were very complicated when they were turned. During brake test, the parameters of tested brake parts would changed because of the changes in operating conditions. In order to improve the adaptability of PID controller parameters so that the control parameters can achieve adaptability, this paper proposed the design of fuzzy PID control system. Firstly, the mechanism of constant-torque braking control system was analyzed, and established transfer function models of the controlled object with brake test conditions by using the least squares offline method of parameter identification system and system identification Toolbox of MATLAB Toolbox for the mathematical models. Then the paper checked the models to judge if the models can be used in simulation experiments. Lastly, it designed the fuzzy PID controller, and designed the simulation experiments of constant-torque brake with fuzzy PID controller compared with conventional PID controller in order to check the applicability of fuzzy PID controller.The experiments results showed that achieve the adaptability of PID control parameters, the fuzzy PID control system achieved much better control effect compared with conventional PID control system, improved the rapidity of the system response and robustness.