电液伺服试验机的QFT控制研究

Research on QFT Control for Electro-hydraulic Servo System

由于电液伺服试验机系统内存在较强的时变特性和非线性,并且试件等负载特性经常变化,导致系统存在很大的参数不确定性。当被控系统的参数等特性发生变化时,采用固定参数的传统PID控制难以获得满意的控制效果,如果重新调整参数又极大地增加了控制操作的复杂性。为解决此问题,采用定量反馈理论(QFT)的控制器设计方案,对电液伺服试验机系统进行控制。QFT控制器是针对系统不确定性做出的设计,对于控制不确定性较强的系统,该控制器具有独特的优势;在系统的不同频段内,QFT控制器还可以“剪裁”系统的控制性能。对具有参数不确定性的电液伺服试验机系统进行试验辨识,并在系统模型上进行QFT控制器设计和仿真。结果表明:在工况发生变化时,所设计的QFT控制器比PID控制器具有更高的控制精度,鲁棒性更好。

Due to the electro-hydraulic servo testing machine has strong time-varying and non-linearity,and load characteristics often change,the system has great parameter uncertainty.When the parameters of the controlled system change,it is difficult to obtain satisfactory control effect by using the traditional PID control with fixed parameters.If the parameters are adjusted again,the complexity of the control operation will be greatly increased.In order to solve this problem,the design scheme of the controller with quantitative feedback theory(QFT)was used to control the electro-hydraulic servo testing machine.QFT controller is designed for system uncertainty.For the system with strong control uncertainty,the controller has unique advantages;the QFT controller can also“tailor”the control performance of the system in different frequency bands.The electro-hydraulic servo testing machine with parameter uncertainty was identified,and QFT controller design and simulation were carried out on the system model.The results show that the designed QFT controller has higher control precision and stronger robustness than the PID controller when the working condition is changed.