Second-Order Discrete-Time Fast Terminal Sliding Mode Control Based on Exponential Reaching Law for Electronic Throttle

In order to achieve precise and robust tracking control of electronic throttle (ET) systems subject to external disturbances and uncertainties, a novel 2-order discrete-time fast terminal sliding mode control (2-DFTSMC) approach is presented in the paper. Specifically, a novel recursive nonlinear discrete-time sliding surface is developed by utilizing the fast terminal sliding surfaces and principles of high-order sliding mode (HOSM). Compared with previous methods, the proposed hierarchical two-layer discrete-time sliding surface has the capability to suppress the chattering and reduce the tracking error. Then, in order to further improve the system convergence dynamics, the improved exponential reaching law and disturbance estimator are also employed. Rigorous theoretical analysis proves that the quasi-sliding mode (QSM) exists and the tracking error is reduced. Finally, through experimental comparisons, it is verified that the proposed 2-DFTSMC approach is superior to traditional DLSMC and DFTSMC, which demonstrates the advantages and effectiveness of the 2-DFTSMC scheme with the recursive discrete-time sliding surface.