Design of coefficient diagram method (CDM) based PID controller for double integrating unstable system

Control of double integrating unstable system is a challenging task in the field of control system engineering. Many Proportional Integral Differential (PID) controller design is developed for stable system however it is very less common for double integrating unstable system. Co-efficient Diagram Method (CDM) is one of the recently developed controller design methodology based on algebraic approach. In this paper, a new CDM based PID control strategy is proposed for double integrating unstable system. An example is given to demonstrate the performance and robustness of the CDM-PID controller in terms of Error indices (Integral Squared Error (ISE) and Integral Absolute Error (IAE)) and Quality indices (Rise time (t_r), Settling time (t_s and Maximum peak overshoot (%Mp)).