叠堆式超磁致伸缩致动器的模型预测滑模控制

Model predictive sliding mode control for stack giant magnetostrictive actuators

根据新型电液伺服阀的驱动要求,设计了叠堆式超磁致伸缩致动器(SGMA),为补偿其固有的非线性,提高位移输出精度,研究了SGMA的控制策略,并对控制策略进行了仿真和实验验证。首先,采用永磁体和GMM棒交替排布的结构形式设计了SGMA,有助于提高偏置磁场的均匀性;然后,根据SGMA的结构特点,将其视为多自由度振动系统,建立了系统的位移输出模型;接着,在输出模型的基础上,结合模型预测控制与滑模控制策略,设计了模型预测滑模控制器;最后,进行了控制策略仿真和实验验证。实验结果表明,模型预测滑模控制器能够实现SGMA的精密控制。在阶跃控制实验中,系统稳定时间低于1.5ms,无超调和稳态误差;在正弦控制实验中,系统最大控制误差约为0.83μm,相对值约为6.9%,证明了控制策略的有效性。

According to the requirements of actuators for novel electro-hydraulic servo valves（EHSVs）,this paper proposes a design for a special stack giant magnetostrictive actuator（SGMA）.In order to compensate for the nonlinear property of the SGMA,a controlling strategy was proposed and verified by simulation and experimentation.First,with permanent magnets（PMs）and short giant magnetostrictive material（GMM）rods located iteratively,a highly uniform bias magnetic field was obtained in the SGMA.Then,based on the structure of the SGMA,a multi-DOF model was established to describe the dynamic properties of this actuator.In addition,a control methodology was developed,which combines model predictive control and sliding mode control.Finally,to validate the proposed controller,both simulation and experimentation are conducted,and the results indicate that the proposed controller can realize the ultra-precise control of the SGMA.In the step control experiment,the system achieves stability within 1.5 ms with no overshoot or steady-state error.In the sinusoidal control experiment,the maximum tracking error of the system is approximately0.83μm,6.9% of the total output of the SGMA,proving that the model predictive sliding modecontrol can significantly reduce the nonlinearity of the SGMA.