Adaptive Second Sliding Mode Control for Stabilized Platform of Rotary Steering Drilling Tool

This paper proposes an adaptive second sliding mode (SOSM) control strategy to control the stabilized platform of rotary steering drilling tool. Stabilized platform is typical uncertain system, and using traditional sliding mode control (SMC) needs to know the upper bound of uncertainty firstly, which cannot be satisfied for stabilized platform under work condition. Meanwhile, the input chattering phenomenon exists inevitably. Therefore, using adaptive SOSM method can solve the two problems. SOSM controller eliminates the input chattering, and the design of adaptive tuning law for SOSM controller overcomes the limitation of prior knowledge about the uncertain upper bound. Simulation results show that the proposed control strategy can make stabilized platform achieve good control performance and robustness.