# Design and Analysis of the Composite Stability Control of the Reflective Optoelectronic Platform
###### Abstract  
To improve image object detection and tracking, researchers have been exploring methods to enhance the stability and precision of optoelectronic platforms' line of sight (LOS). The innovation of stability mechanisms is the key driver of this breakthrough. This study presents a composite stability control system for reflective optoelectronic platforms using the integral composite stability principle. A platform kinematic model was established based on multi-body kinematic theory, and a composite stable control strategy was designed. The strategy includes coarse stability design and fine stability design based on residual error feed-forward correction. The performance of the control strategy was analyzed in terms of dynamics, current loop control effects, and loop structure. The proposed control strategy was simulated and experimentally verified for fixed-frequency angular velocity disturbance and translational disturbance. The stability accuracy index of the system was significantly improved after compensation, with improvement of more than 75 times for fixed-frequency angular velocity disturbance and more than 37% for translational disturbance. Comparative experimental results with traditional stable methods show that the proposed composite stable control strategy can significantly improve the system stability, with stability accuracy index improvement of one to two orders of magnitude in micro-radian units compared to traditional algorithms. photoelectric detection device; line of sight stability; reflector stability; composite stability Article Design and Analysis of the Composite Stability Control of the Reflective Optoelectronic Platform  
K.-Y. torque that restricts further improvement of the stability precision. Recent studies on the two-axis two-framework application are exploring ways to treat friction as a disturbing or unmodeled element and improve the precision ability through anti-interference control methods [5; 6; 7; 8]. However, these improvements are often limited. To completely eliminate the effects of friction, a two-axis four-framework application mode was developed, with two internal frameworks for stability control protected by two external frames. This eliminates the need for sealing treatments [3; 9]. Though this principle scheme is more complex, it significantly improves stability precision, achieving a level within one hundred micro-arcs [3; 4]. To further enhance performance, a fast reflector is placed in the optical channel of the two-axis four-framework system, using the high bandwidth and precision of the fast steering reflector to actively compensate loop errors. By optimizing the two-stage method of coarse and fine control, known as the composite stability principle scheme, stability precision is improved by nearly an order of magnitude, reaching a level of ten micro-arcs [4; 10; 11]. The reflector stability mode is an optoelectronic stability solution that is commonly applied to specific types of equipment [11; 12]. This method involves placing a reflector in the LOS of a fixed optoelectronic detector and achieving inertial stability of the LOS by adjusting the reflector's attitude. While this approach is an indirect stability method, the LOS of the detector is calculated using different sensors of inertial, angle, and angular velocity. To eliminate the double effect caused by reflection, a mechanism with a transmission ratio of 2 to 1 is introduced. However, the transmission precision and stiffness are limited, which restricts the improvement of stability precision. Although this approach is still necessary in certain situations, its stability precision is lower than overall stability methods. The papers [13; 14] propose the design of a fused reflector and fast reflector based on the principle of integrated composite stability. This design utilizes the stability of the reflector and error compensation of the fast reflector to establish a stability control system for reflective optoelectronic stability platforms.