Design automation in Quantitative Feedback Theory (QFT) is addressed in
this paper. An automatic loop shaping procedure based on Genetic Algorithms
(GAs) is developed, where a robust controller for uncertain plants can be designed
automatically such that the cost of feedback is minimised and all robust stability
and performance specifcations are satisfed. The developed approach can improve
the current QFT design in at least two aspects. One is in the design of an initial
controller for complicated plants, which might be difficult even to find a stabilising controller manually. The other is in improving the initial manual design by
optimisation of the performance index under the prescribed requirements within
the neighbourhood of the manual design. An illustrative example which compares
manual loop shaping with automatic loop shaping is presented
