Adaptive PI control of a three-tank system with prescribed performance

An adaptive PI control approach for precise water level tracking control in an uncertain three-tank system is presented. By employing a coordinate transformation, we convert the system model into a canonical form that incorporates uncertainties. A higher-order sliding mode differentiator is utilized to estimate the canonical system’s state variables based on the measured water level of the target tank. This enables the design of an adaptive PI controller that effectively compensates for modeling uncertainties while achieving predefined transient and steady-state performance. The control performance is validated through rigorous theoretical analysis and experimental studies.