Software for Robust PID Design

摘要: The PID controller is by far the most common controller in industry today. Even so, a lot of these controllers are poorly tuned. Two of the main reasons for that is lack of knowledge and time among the operators. As a consequence, many controllers are set to default values. In other cases, the derivative part is turned off because it was not used correctly, giving noisy signals. It would therefore be a good idea to educate the operators in the possibilities of the PID controller and to provide them with simple and fast design tools. This report briefly describes a program that achieves both goals and should be useful for people in the industry as well as for academics.There are many PID design methods available today and some of the most famous are collected and analysed in Åström and Hägglund (2005). Of these, the MIGO and AMIGO methods (also see Panagopoulos et al.(2002) and Hägglund and Åström (2004)) are probably those most worth mentioning in connection to this work. They are based on optimization of load disturbance rejection under robustness constraints. A further development of the MIGO method, and largely based on the same method as used in this work, was presented in Nordfeldt (2005). An advantage with Nordfeldt’s method is that it also works for some more advanced process structures. This report focuses on the software that solves the optimization problem and how it can be used to increase people’s understanding of PID control.