摘要:超声波电机是一类具有严重非线性和时变性的被控对象,适用于时变对象的模型参考自适应控制(MRAC)策略可用于超声波电机位置控制。但由于电机存在最大转速限制,需要对MRAC位置控制器的输出进行限幅,这成为导致电机位置响应出现超调及振荡收敛过程的一个主要因素。针对这一问题,本文给出一种三段式的参考模型,根据当前转速变化动态调节参考模型的输出,使得所设计控制器更适合于超声波电机的位置控制。研究表明,所提方法简单、有效,控制效果较好。 关键词:超声波电机;位置控制;模型参考自适应控制;三段式参考模型 Abstract: Ultrasonic motor is a kind of controlled object with severe nonlinearities and time variability. Since the Model Reference Adaptive Control (MRAC) strategy is very suitable for timeverying objects, so it can be applied in the position control of ultrasonic motor. It is necessary to limit the output of the MRAC position controller because there is a maximum speed limit of the motor. And this problem would become one of the main factors that leading to the position response overshoot and oscillatory convergence. To solve this problem, this paper presented a threestage reference model that the output of the reference model was adjusted dynamically according to the current speed change, thus the controller is more suitable for the position control of ultrasonic motor. Application shows that the proposed method is simple, effective and with better control performance. Key words: ultrasonic motor; position control; model reference adaptive control method; threestage reference model
|