基于压电驱动器的Stewart微动平台迟滞补偿和解耦控制研究

Hysteresis compensation and decoupling control of Stewart micro-motion platform based on piezoelectric actuator

针对基于压电驱动器驱动的Stewart微动平台同时存在强耦合性和迟滞特性的问题,对Stewart微动平台的耦合特性和迟滞特性进行了研究。对耦合特性与迟滞特性的特点进行了归纳,提出了一种基于迟滞补偿和输入端解耦的控制方式,建立了数学模型,并设计了控制器;先通过旋转变换矩阵进行了位姿反解,得出了Stewart平台各支腿长度;再在系统动力学模型的基础上,通过在输入端引入动力学逆模型的方法,对系统进行了输入端解耦,采用Bouc-Wen模型来描述压电驱动器的迟滞特性,并用逆模型方法对迟滞特性进行了补偿;最后设计了控制器,并通过仿真验证了定点运动和连续运动两种方式的有效性。研究结果表明:该控制方式能同时对压电驱动器驱动的Stewart平台进行迟滞补偿和解耦控制,响应速度快、稳定性好。

Aiming at the problem of strong coupling and hysteresis characteristics of Stewart micro-motion platform driven by piezo driver, the coupling characteristics and hysteresis characteristics of Stewart micro-motion platform were studied. The characteristics of coupling characteristics and hysteresis characteristics were summarized.A control method based on hysteresis compensation and input decoupling was established. The mathematical model was established and the controller was designed.Firstly, the length of each leg of the Stewart platform was obtained by the inverse transformation of the rotational transformation matrix. Then, based on the system dynamics model, the input end was decoupled by introducing the dynamic inverse model at the input.The Bouc-Wen model was used to describe the hysteresis characteristics of the piezoelectric actuator and the inverse model was used to compensate the hysteresis characteristics. Finally, the controller was designed and verified by simulation to verify the effectiveness of both fixed-point motion and continuous motion.The results indicate that the control method can simultaneously provide hysteresis compensation and decoupling control for the Stewart platform driven by the piezoelectric actuator, and the response speed is fast, and with good stability.