An integral sliding mode controller based disturbance rejection compound scheme is proposed to attenuate the influences of nonlinear disturbances and parameter uncertainties on stability accuracy of the three-axis inertially stabilized platform for the aerial remote sensing applications. The compound scheme is composed of an integral sliding mode controller and a disturbance measurement unit. The integral sliding mode controller is used to ensure robust stability against exterior nonlinear disturbances and parameter uncertainties, in which the saturation function is employed to reduce the chattering. The disturbance measurement unit is served as the disturbance measurement components of the rate loop and current loop of three closed-loop structure in the inertially stabilized platform control system, by which the interior high-frequency disturbances are compensated in real time. To verify the method, simulations and experiments are conducted. In simulations, the LuGre friction model is introduced to analyze the effects of disturbances. Further, a series of experiments are carried out. The results show that the compound scheme has excellent ability in both of disturbances rejection and robust stabilization, by which the stability accuracy of the inertially stabilized platform is improved significantly.
Control System Design for a Three-Axis Inertially Stabilized Platform in Aerial Remote Sensing