Robust Sliding Mode Single Output Process Control

This note evaluates the performance of several adaptive second-order sliding mode (ASOSM) controllers in regulating the liquid level in a three-tank system. There are two conflicting merits: uniformity in the system performance at various operating points and chattering in the control signal. After best tuning of the methods, it is realized that the M3 design is a chattering-free one, and the M2 design yields a lower level of error in regulation and disturbance rejection of the designs. Thus, none of them can collectively fulfill the design objective and the design of choice remains highly application-dependent.