A non-linear PD controller for pure integrating process with delay

Performance of PID controller for integrating process with delay (IPD) is usually found to be poor due to large overshoot. In this regard PD controller seems to be a good alternative for such processes. IPD model is a good approximation for a number of practical systems. Here, we propose an on-line non-linear parametric scheme for PD controller to achieve improved performance of IPD processes. Lower overshoot with faster settling during set point response and improved load rejection behaviour are the key features of the proposed non-linear PD (NPD) controller. Enhanced performance of the proposed controller is experimentally verified on IPD process models as well as on a laboratory scale DC servo motor position control system.