超磁致伸缩执行器动力学模型及数值模拟

为提高超磁致伸缩执行器的控制精度,实现亚微米级的驱动与控制,准确描述执行器的动力学特性是关键环节之一.为建立超磁致伸缩执行器的动力学特性的数学模型,将Terfenol-D 棒作为粘弹性杆连续系统,将Terfenol-D棒在磁场驱动下产生的应变等效为磁-机械转换等效力,建立了执行器系统的一维波动方程,并采用有限元解法求解.模型的计算求解采用迭代方法,易于实现计算机控制.利用Matlab 7.0对不同频率等幅磁场驱动下Terfenol-D棒内的磁场-位移(H-u)曲线进行数值模拟仿真,仿真计算值与实验值误差在10%以内,表明建立的动力学模型能较好地反映磁致伸缩执行器的动力学特性.

Dynamics model and numerical simulation of giant magnetostrictive actuator

An accurate dynamics model is crucial to enhance the control accuracy and implement the submicron control for the giant magnetostrictive actuator . To describe the dynamics characteristics of the giant magnetostrictive actuator precisely, a dynamics model is presented. Regarding Terfenol-D rod as a viscoelastic rod continuous system and treating the induced strain by external magnetic field as equivalent force, a one-dimension wave equation for the actuator is built. The solution of the equation by finite element method is given with the iterative method. The model is easy to utilize for the real-time implementation. It provides the experimental data and numerical simulated data calculated with Matlab 7.0 by magnetic field versus displacement (H-u) curves under the different frequencies and the same magnetic field drive level .The simulated and experimental results with the error within 10% indicate the validity of the model.