A Novel Approach Based on Terminal Sliding Mode Control for Optimization of Nonlinear Systems

It is difficult for many discrete nonlinear systems to quickly meet control requirements and establish accurate dynamic models. This study presents a control strategy that combines model-free adaptive control and discrete terminal sliding mode control to solve these problems. A novel discrete terminal sliding surface is designed in this strategy. It not only avoids the establishment of system models but also achieves quick response. Firstly, a perturbation observer is established to estimate perturbation of the system and time - varying parameter pseudo - gradient is estimated from input and output data of the system. Secondly, the controller combining the partial form dynamic linearization model free adaptive control and discrete terminal sliding mode control is designed. The stability and convergence of the proposed strategy are proved in theory. Thirdly, the proposed strategy is compared with PID technique and the method of combining model free adaptive control(MFAC) with discrete sliding mode control in chemical system and water tank system respectively. Simulation examples demonstrate that the proposed strategy is superior to others in terms of fast response. This study provides a reference for solving the control problem of discrete nonlinear systems.