空间高精度扫描伺服系统的驱动控制

研究了空间飞行器扫描伺服系统的高精度驱动控制技术。针对有效载荷对地面目标进行扫描时多要求其伺服系统提供高精度的低速性能,本文提出采用交流永磁同步电机直接驱动伺服系统,省去中间的减速器传动环节来提高伺服系统的驱动控制精度。伺服驱动控制系统用现场可编程门阵列(FPGA)作为高速信号处理芯片,提高信号的处理速度和控制精度;用高精度的绝对式光电编码器检测转动位置,提高位置检测和速度的精度;主电路采用功率线性放大技术,得到光滑,力矩脉动小的驱动波形。系统实验表明,由于该方法采用模拟正弦信号驱动,在低速时避免了脉宽调制(PWM)驱动信号开关和死区造成的速度波动,实现了高精度的速度控制,速度波动范围在1%以内;得到的电压、电流测试曲线光滑,无高次谐波干扰。该扫描伺服系统满足动态和静态要求,为实现空间低速高精度扫描提供了一种新的方法。

Driving and controlling of high accuracy scanning servo-system in space

A high accurate servo control technology was explored for the scanning servo-system of a spacecraft. When payloads such as space communication, observation and reconnaissance scan the targets on the ground, the servo system of payloads usually is required to provide high accuracy and low speed performance. So, this paper proposes a control scheme by using a Permanent Magnet Synchronous Motor (PMSM) as the servo driving system. It avoids the middle processing of a reducer and improves the control accuracy of servo system. A Field Programming Gate Array(FPGA) was used in the servo driving control system as the signal processing chip to improve the process speeds and control accuracy, and a higher precise absolute photoelectric encoder was taken to detect the rotation position to increase the detection accuracy of the speed and position. Furthermore, a power linear amplification was used in the main circuit to obtain smoother and smaller fluctuation wave forms. As the control scheme uses simulation sinusoidal signal driving and it avoids speed fluctuation come from switching and dead zones of the pulse width modulation(PWM) signals in low speeds, the experiments indicate that the control scheme realizes the speed control with high accuracy. The speed is smooth, and the speed fluctuation is within 1% when the operating is in an even speed. Moreover, the testing curves of the voltage and current are smoother without harmonic disturbance. The scan servo system meets the requirements of dynamic and static experiments, and provides a new solution for low speed and high precision scanning servo systems.