非共振式压电直线电机精密驱动及定位控制

Precision drive and position control of non-resonance piezoelectric stack linear motor

为实现光机结构、集成电路等领域中大行程及高精度的位移控制,利用较为适用的非共振式尺蠖型压电直线电机,基于高压功率运算放大器,设计了非共振式压电直线电机的精密复合放大驱动电路,通过理论分析及实验得到的伯德图验证了驱动电路的分辨率和幅频特性。以现场可编程门阵列(FPGA)为核心处理器,以光栅尺为反馈元件,通过分析非共振式压电直线电机的多种运行模式,根据直线电机的运行时序,设计完成了开环大范围整步运行模式与闭环小范围单步运行模式相结合的控制策略,在单步运行模式中分别设计完成了PID控制算法及PID与压电陶瓷迟滞逆模型前馈相结合的复合控制算法。实验结果表明,该控制策略能够实现大行程内的精密位移控制,复合控制算法具有比PID更加优越的控制效果,能够在21mm大行程内实现1.5nm的闭环定位控制精度,直线电机的最大驱动力可达300N,满足大行程高精度位移控制的应用需求。

In order to realize long stroke and high precision displacement control in scopes such as opti- cal-mechanical structure, integrated circuit and so on, a precision hybrid amplification driving circuit was designed by using non-resonance piezoelectric inchworm stack linear motor based on the high volt- age power operational amplifier. Resolution and amplitude-frequency characteristic of driving circuit were verified by Bode diagram gotten by theoretical analysis and experiment. Taking FPGA as core processor and grating ruler as feedback element, through analyzing various operation modes of non- resonant piezoelectric linear motor, according to the operation sequence of linear motor, a control strategy combining the open loop large range whole step mode with closed-loop and small-range single step operation mode was designed and finished. Two types of control algorithms of PID and compound control of combination between PID and feed forward of hysteresis inverse model of piezoelectric ce-ramic were designed respectively in single step operation mode. Experimental results indicate that the control strategy can realize precise displacement control. Compound control algorithm has more supe- rior control effect than PID. Moreover, its closed-loop position control precision can reach 1.5 nm in large stroke of 21 mm. I.inear motor can realize maximum driving force of 300N and satisfies applica- tion demands of high-precision displacement control in large stroke.