Dual-Motor Drive Image Stabilization System for Elevation-Azimuth Photoelectric Survey Telescope Under Long Exposure

Elevation-azimuth photoelectric survey telescopes working under long exposure station is very important for observing weak targets in space. The motion characteristics analyses including position and velocity of rotating targets show that the image stabilization system (IMSS) needs to have a self-locking capability, low temperature rise, anti-interference, high-speed switching, and ultralow-speed tracking performance. A dual-motor drive IMSS with self-locking was adopted after comparison. In this work, in order to overcome the inherent uncertainties affecting the accurate tracking of a target in a dual-motor driving gears of the IMSS, we introduce a compound control strategy including bias torque controller in current-loop and active disturbance rejection controller in velocity-loop. Experimental results show that the proposed controller can effectively eliminate backlash of IMSS, and the fixed-point control accuracy can achieve 0.18 arcs. When the sinusoidal speed guidance is 0.068 sin (2π × 0.01 × t) (°/s) and position guidance is cos (2π × 0.01 × t) (°), the position error is 0.31 arcs. After image stabilization, the imaging resolution can be guaranteed to reach within 0.5-pixel under the 60 s exposure time.