Model-free approach to controlling nonlinear systems with single output delay

A recently introduced technique called Advanced Disturbance Rejection Control (ADRC) lays out the principles of designing controllers for nonlinear systems without explicitly knowing the system model. In this paper, we study ADRC in the presence of a single output measurement delay, which may destabilize the observer segment of the ADRC and in turn destabilize the overall nonlinear system. We develop tools to select the controller gains of this observer, which concerns the linear control design, so that the observer can be made asymptotically stable for a range of delays including the output delay. A case study is presented to demonstrate the control implementation on a nonlinear system.