Designing the feedforward part of 2-d.o.f. industrial controllers for optimal tracking

This paper presents and discusses a causal method to design the feedforward part of 2-d.o.f. industrial controllers for optimal tracking, independently of the structure of the feedback controller, of the way it was designed, and of the characteristics of the set point signal. The method is particularly well suited for embedded systems, or wherever the limits imposed by the hardware and/or software architecture are relevant, is based on a nonparametric model of the control loop, that can be easily identified on-line, and allows to cast various tracking problems into a unified optimisation framework. Several experimental examples, covering various application domains, demonstrate the method's effectiveness, simplicity, and practical usefulness, giving also an idea of different design scenarios, i.e. applications where set point tracking, disturbance rejection, stability and robustness have different relative importance.