Fault-tolerant Satellite Attitude Tracking by Modified Non-Singular Fast Terminal Sliding Mode

摘要

A modified non-singular fast terminal sliding mode as a fault tolerant control method is employed to track desired attitude of a satellite with three magnetorquers and one single reaction wheel subject to actuator faults and unknown external disturbances. Because satellites are a time-critical system, sliding variable is chosen so that the satellite attitude converges to a desired trajectory in a finite time. Furthermore, this sliding variable causes to avoid singularity. Numerical simulations are used to evaluate performance of the proposed controller for satellite attitude tracking control problem in the presence of given conditions. In addition, first and second order SMC methods are utilized to compare the performance of proposed controller.