超声电机驱动的轻量化扫描机构高精度控制

High Precision Control Method of Lightweight Spatial Scanning Drive Mechanism Based on Ultrasonic Motor

为实现卫星高分载荷扫描驱动机构的轻量化,以超声电机为驱动部件,设计了一款扫描驱动机构,质量仅为传统的步进电机加谐波减速器驱动方案的15%。构建了扫描驱动机构驱动控制器,配合21位绝对式光电编码器作为位置反馈传感器,对扫描驱动机构高精度控制方法进行了研究。针对超声电机在精密控制中的非线性及时变性,在对比总结比例、积分、微分(PID)控制、模糊控制、神经网络PID控制算法的基础上,设计了一种基于专家规则的PID控制器,并结合超声电机实时温度作为前馈控制在线调节控制器控制参数,最后进行了指向控制和速度稳定度实验研究。实验结果表明:令扫描驱动机构指向20°时,稳态指向精度优于2″,在3.3r/min情况下扫描驱动机构速度稳定度优于±1%,能够满足卫星载荷对扫描驱动机构高精高稳的控制需求。

In order to realize the lightweight of the spatial scanning drive mechanism in the high-resolution satellite payload, a scanning drive mechanism is designed with the ultrasonic motor as the driving component. The weight is only 15% of the conventional drive scheme combining the step motor with the harmonic reducer. A drive control system of the scanning drive mechanism is built. The equipment is used to test the high precision pointing control method of the scanning drive mechanism with the help of the 21-bit absolute photoelectric encoder as the position feedback sensor. By comparing the efficiency of PID control, fuzzy control and neural network PID control algorithm, the ultrasonic motor temperature detection is taken as the forward feedback control on-line regulation control parameter considering the nonlinearity and time-variation of ultrasonic motor and hence a novel expert rule PID controller is proposed. The experimental results show that when the scanning drive mechanism is pointing at 20°, the steady-state pointing accuracy is better than 2＂, and the speed stability of the scanning drive mechanism is better than ±1% at 3.3 r/min, which meet the requirement of satellite payload for high precision and high stability control of the scanning drive system mechanism.