Implementation of fixed structure QFT prefilter synthesised using interval constraint satisfaction techniques

Prefilter synthesis is one of the important design steps of Horowitz’s Quantitative Feedback Theory (QFT) to robust feedback system synthesis. The prefilter is designed to achieve tracking specifications. A new, computationally efficient approach for automation of the prefilter design step is proposed. In the proposed approach, the prefilter design problem is posed as an Interval Constraint Satisfaction Problem (ICSP) and solved using established Interval Constraint Satisfaction Techniques (ICST). To validate the above design approach we apply the method to a benchmark problem as well as laboratory set-up of industrial plant emulator and obtain simple, low-order QFT prefilters.