无模型控制器在气缸压力控制系统中的应用研究

Model-free Adaptive Controller and Its application in Cylinder Pressure Control System

气动伺服系统存在纯时延、非线性、时变等特点,传统的控制策略(如PID控制)在解决非线性系统时效果不理想,因此提出一种无模型控制算法。此方法在被控对象结构复杂、参数时变时控制效果较好。首先对气动伺服系统进行建模,建模过程包括阀口流量、比例流量阀及缸内压力建立一个二阶模型;其次设计无模型自适应控制器(Model-Free Adaptive Controller,MFAC)用于气动伺服系统压力控制;最后利用LabWindows/CVI平台进行试验验证。结果表明,针对气动伺服系统设计的无模型控制器是有效的,相比于传统PID控制有更快的响应速度和更高的控制精度。

A pneumatic servo system has characteristics of pure delay,nonlinearity,time-varying,etc.A model-free control algorithm is proposed,because the traditional control strategy such as PID control is not ideal for solving nonlinear systems.The control effect is better when the controlled object has a complex structure and time-varying parameters.Firstly,a pneumatic servo system is modeled.The modeling process includes valve port flow,proportional flow valve and in-cylinder pressure,and we establish a roughly accurate second-order model.Secondly,a model-free adaptive controller is designed for pressure control of a pneumatic servo system.Finally,the Labwindows/CVI platform is used for experiment verification.The results show that the model-free adaptive controller designed for pneumatic servo system is effective and has faster response speed and higher control accuracy than traditional PID control.