Advanced PID tuning for unstable processes based on a new robustness specification

PID control is widely used to control stable processes; however, its application to unstable processes is less common. In this paper, we proposed a simple PID controller tuning method for unstable processes with time delay to meet a new robust specification. With the proposed PID tuning method, we can obtain a loop transfer function with the real part close to -0.5. This guarantees both robustness and performance. Simulation examples are given to show the performance of the method.