Soft variable structure control based on implicit Lyapunov functions: A control strategy

For the problem of chattering for variable structure control system, based on implicit Lyapunov functions, a new control strategy, soft variable structure control(SVSC), is presented. Firstly, the definition of SVSC and the construction of its controller are given. SVSCs for unrestricted controls and restricted controls are given by employing implicit Lyapunov districts and designing soft variable structure controllers, and SVSC systems with state observer are analyzed at the same time. SVSC is developed based on variable structure control lacking sliding modes, which can decrease the system chattering effectively, keep regulation rates high and shorten settling times. The simulation result shows the feasibility and effectiveness of the proposed approach.