Comparison of 2DOF GMVC-based PID control laws

This paper discusses a design method for a Generalized Minimum Variance Control (GMVC)-based Proportional-Integral-Derivative (PID) control law in a two-degree-of-freedom (2DOF) system. The PID parameters of a PID control law are designed based on GMVC and are updated using the self-tuning method. In the conventional method, a 2DOF PID control law is based on GMVC with a feed-forward compensator (abbreviated as FF-type GMVC), and the feed-forward compensator is approximated by a PID compensator, but the structure of the PID compensator is restricted and the order of the feed-forward compensator is decided by the length of a dead-time. Therefore, the approximation accuracy deteriorates if the dead-time is long In this study, a 2DOF PID control law is newly designed based on a PC-type GMVC that 2DOF GMVC is designed using a pre-compensator, and the approximation error caused by the structure of a 2DOF system is investigated. Furthermore, it is clarified that the FF-type and PC-type GMVC-based PID control laws are not same although the PC-type and FF-type GMVC laws can be designed equivalently.