Backstepping control for two tanks process based on adaptive high gain observer

This paper introduces a new output feedback control scheme, which combines nonlinear backstepping control with an adaptive high gain observer. The advantage of this type of control lies in the simplicity of the control law algorithm by putting the considered system in a “Strict feedback Form” which is a class of systems uniformly observable and commandable. We consider nonlinear SISO class of systems that include the model of our hydrographic system. Only one sensor is available to measure the liquid level in the bottom tank and the other process's states and parameters are assumed unavailable. Hence, the incorporation of an adaptive observer is proposed to solve this problem. Thereafter, all estimated variables are online recovered during the control operation.