A reaching-law method for uncertain discrete variable-structure control systems
不确定离散变结构控制系统的趋近律方法

Existing design methods for uncertain discrete variable-structure control systems(UDVSCS) are discussed.An improved reaching-law for UDVSCS is proposed based on the sigmoid function. By applying the proposed reachinglaw to UDVSCS, the stability of origin and the smoothness of the converging process of the system are better than those obtained by using the exponential rate reaching-law and the variable rate reaching-law; the system states are kept in a single converging pattern during the process of reaching the origin. With this design method, the sliding surface can be reached quickly and the system chattering can be reduced at the same time, facilitating the design of variable-structure control. Simulation results show that the proposed method is feasible and effective.