Fixed-time Sliding Mode Control and High-gain Nonlinearity Compensation for Multi-motor Driving System

A two-stage design procedure combining the strength of a fixed-time sliding mode control and a high-gain compensator for deadzone nonlinearity is proposed for a multimotor driving system. A novel practical fixed-time convergent controller is designed for the perturbed system, which improves the applicability of the proposed method. The concept of multisurface sliding mode is used to cope with the load tracking problem and can guarantee fixed-time convergence, which is regardless of initial states of the system. The convergence time can be known as a priori and a satisfactory dynamic performance can be obtained. Meanwhile, the fixed-time convergent synchronization controller is designed to guarantee the synchronization of driving motors. Then, a high-gain nonlinearity compensator is designed to reduce performance degradation caused by the deadzone nonlinearity. Its simple form makes it more practical and reliable to use than existing compensation methods. Comparative experimental results demonstrate the efficacy of the developed control scheme.