形状记忆合金驱动器的自适应滑模反步控制

Adaptive backstepping sliding mode controller for a shape memory alloy actuator

形状记忆合金(SMA)作为一种智能材料,相对于传统的驱动器具有功率重量比大、驱动电压低、质量轻、干净、无噪音等特性,被广泛应用在各领域.然而,非线性、迟滞、时变等因素影响了形状记忆合金的控制精度,限制了它的应用.为此,本文提出了自适应滑模反步控制方法,用于解决精确控制问题.文中首先搭建了实验装置,建立了形状记忆合金的机理模型;然后,采用最小二乘算法辨识了模型参数;最后,基于机理模型设计了自适应滑模反步控制器.实验结果表明,本文提出的方法具有动态响应快、跟踪精度高和抗干扰能力强的特性.

Shape memory alloy(SMA)is a new type of intelligent material,which has been applied in plenty of fields.Compared with the traditional actuators,it has some prominent merits,such as high power-to-mass ratio,low driving voltage,light weight,clean and quiet operation.However,the nonlinearity,hysteresis and time-varying characteristics have seriously affected the control performance and limited its application.To this end,this paper presents an adaptive backstepping sliding mode control method,and considers the precise control problem of SMA actuators.Firstly,the experimental setup has been established and the physical model of a SMA actuator system has been built up.Next the model parameters have been identified by utilizing the nonlinear least-squares algorithm.Then the adaptive backstepping sliding mode controller has been designed based on the obtained mechanism model.Finally,the experimental results demonstrate that the proposed controller ensures fast dynamic response speed,low steady-state tracking error and reliable disturbance rejection ability.