A Study on Robust Fault-tolerant Control for a Low-cost Target Tracking System

This paper presents a robust control system for a low-cost tracking system. As the controlled apparatus, a 2-axis gimbal is involved in a networked control system and an unreliable gyro sensor is used. Besides, external disturbances heavily affect the system performance. Thus, an unknown input observer is proposed to identify the sensor fault accurately even in the presence of the disturbances and time-varying delay of the networked system. Their influences are estimated subsequently. Then, a fault-tolerant controller is designed, using the observed fault and disturbances. The continuous control law is obtained based on the super-twisting algorithm, backstepping procedure, and integral sliding mode control technique. Finally, a simulation in a worst-case scenario validates the efficiency of the proposed control method. Compared to other control systems, the proposed controller has shown its superiority and reliability.