Research On Characteristic And Control Strategy Of Pneumatic Control Force System

Pneumatic force control systems have been widely used in engineering, such as material testing machine, fatigue testing machine structures. In practice, pneumatic control systems are usually used by people who don't know pneumatic systems very well. The control parameters need to be readjusted, when parameters of the load or the pneumatic components change. It's time-consuming and restricts the promotion of pneumatic control systems. In this paper, a general controller is designed on the base of research on characters and control strategy of the pneumatic force control system, in which, the control parameters can be self-adjusted when the basic parameters of the system change.In this paper, the mathematical model is built by some basic theorem, and the transfer function model is established based on the linearization of the mathematical model. On the basis of the transfer function, pneumatic force control system is analyzed from the perspective of frequency domain. Through the analysis of spectrum of the input signals, it's pointed out that control method differs depending on the type of input signals.The controller of the pneumatic force control system is designed, in which ramp signals and sine signals are controlled by proportion algorithm while step signals is controlled by the combination of proportional control and acceleration feedback and double inertial link correction is infeasible. The control algorithm is determined by the frequency domain analysis, and parameters of the controller are adjusted by the fuzzy controller based on the piston position, so the parameters of the controller are self-adjusted.The model of the pneumatic control system is built in Simulink. The system is well controlled in simulation when basic parameters are set. The nonlinear factors of the system are analyzed, and it's concluded that controller based on linear transfer function and control parameters adjusted can achieve good performance for nonlinear pneumatic force control systems.The experimental platform of the pneumatic force control system is built, which uses C language software platform for signal acquisition and output control. When the basic parameters of the system are set, the control effect is good in different input signals, which verifies the validity and practicability of the controller.