Design of Adaptive PID Controllers Subject to Process Constraints

This paper presents a new method to design adaptive Proportional-Integral-Derivative (PID) controllers which optimize a performance criterion (integral absolute error or integral square error) subject to constraints such as controlled variable, manipulated variable and rate of change constraints. The design method is applicable to linear or nonlinear processes. Modeling of such processes is done using a linear ARX model. In addition, the design method is independent of the PID controller type and accounts for controllers with proportional or derivative action on the control error or the process variable. The proposed design method is not analytic in nature, but rather it is implemented using existing MATLAB optimization functions and demonstrated using simulation experiments for linear and nonlinear processes.