A mixed sensitivity optimization design for a benchmark control problem

This paper explores a numerical approach of a mixed H² sensitivity optimization technique to re-design a robust controller for the Grumman F-14 aircraft, one of the IEEE Control Systems Society´s benchmark control problems. By operating in the Discrete Fourier Transform (DFT) domain, we convert the H² control problem into a constrained vector minimization problem in the l²-space. A two-stage solution approach is detailed and the controller is then constructed. The advantage of using the proposed method is that the l²-space solution can be analytically expressed and efficiently calculated via existing multichannel algorithms due to the partially block circular structure of the matrices involved in the DFT domain. The approximation can be made arbitrarily close to the original H² control problem if the number of the DFT points is large. The simulation results are presented to demonstrate the proposed method.