Nonlinear sliding mode control with backstepping approach for a nonlinear three tank system

In this paper, the nonlinear sliding-mode control combined with the backstepping approach for a three tank system is proposed. The recursive nature of this approach is similar to the standard backstepping, and the difference is that we use backstepping to design virtual controller including a zero-order sliding mode at each recursive step. Stability analysis results are discussed, which show that the closed-loop system is ultimately bounded. The application of the proposed controller to a real three tank system is also presented; some results are included to demonstrate the good performance of the proposed controller.