PI-PD controller design for unstable processes with time delay

A new method for PI-PD controller tuning based on direct synthesis for integrating and unstable processes with time delay. Guidelines are provided for selection of the desired closed loop transfer function in the direct synthesis method and adjustable parameter ω. Design for some typical unstable processes with time delay shows that the PI-PD controller can reduce the overshoot effectively and achieve good tradeoff between dynamic performance and robustness.