Decentralized sliding mode control in three-axis inertial platforms

Abstract

The accuracy improvement of three-axis inertial platform stabilization systems with a dynamically tuned gyroscope sensor is addressed by methods of variable structure control. The decentralized sliding mode control strategy has been worked out and applied for the design of the stabilization system of the three-axis inertial platform. The nonlinear transformations of bases in the nonlinear interconnected subsystems have been found, based on remaining dynamics. These transformations changed the subsystems to the forms convenient for the sliding mode synthesis. The local sliding manifolds have been designed in the form of nonlinear functions and nonlinear dynamic operators to provide the desired linear decoupled output tracking (stabilization) in each axis of the inertial platform stabilization system. The system with the dynamic sliding mode controller obtained the combined features of the system with a conventional dynamic compensator (accommodation to unmatched disturbances) and a conventional sliding mode controller (insensitivity to matched disturbances). The results of the simulation of the three-axis inertial platform stabilization system with the designed conventional and the dynamic sliding mode controllers showed significant improvement of the accuracy (2-3 tunes better then in the systems with linear controllers) of the platform stabilization.