Nonlinear integral sliding mode variable structure control for two-tank system with input — Limitation

To deal with the unsatisfactory transient response of the conventional integral sliding mode control (ISMC), A nonlinear integral sliding mode controller (NISMC) is proposed in this paper, which uses a smooth nonlinear function with “small error amplification and large error saturation” property, meanwhile, takes the limited input into account. The proposed NISMC improves the transient performance, i.e., less controller chattering and less steady error. The two-tank system is usually treated as a paradigm to test the control algorithms. Five kinds of sliding-mode control methods (SMC) are used to control the two-tank liquid level to test the performance. The simulation and experimental results show that the proposed NISMC has the superior performance as compared to the comparison methods.