Improved PID controller tuning rules for performance degradation/robustness increase trade-off

Abstract

Definitely, robustness is an important feature that any control system must take into account, especially considering that the design is usually based on low-order linear models that represent the whole controlled process. The problem is that to include such characteristic implies a degradation in the system’s performance. With regard to the previous statement, this paper is concerned with the design of the closed-loop control system, to take into account the system performance to load-disturbance and to set-point changes and its robustness to variation of the controlled process characteristics. The aim is to achieve a good balance between the multiple trade-offs. Here, a PID control design is provided that looks for a robustness increase, allowing some degradation in the system’s combined performance. The proposed approach is complementary to the work presented by Arrieta and Vilanova (Simple PID tuning rules with guaranteed Ms robustness achievement, in 18th IFAC world congress, 2011; Ind Eng Chem Res 51(6):2666–2674, 2012. doi:10.1021/ie201655c); Arrieta et al. (Performance Degradation Driven PID controller design, in PID12, IFAC conference on advances in PID control, 2012).