A Recursive Terminal Sliding Mode Fault-Tolerant Control for Free Floating Space Robots

Abstract:
The purpose of this paper is to introduce a recursive terminal sliding mode for designing a fault tolerant control system for space robots with bias faults and loss-of-effectiveness faults. With the application of the space robots on the space station, the fault tolerant control is necessary to deal with the inevitable faults of the actuator of the space robots. To settle the problem, first the dynamic equation of the space robot with both faults was derived using Lagrange equation. Next, in order to estimate the lump uncertainty of external disturbances, dynamic uncertainties and faults of the space robots, an observer is used, and further more a recursive terminal sliding mode controller is designed to realize active fault tolerant control for the system, and the convergence time can be adjusted by the coefficients of the controller. Finally, the simulation results verify that the proposed scheme is able to realize the fault tolerant control with less convergence time, smaller error and excellent fault tolerant control ability.