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

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 \(M_s\) 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).