Selection of optimal control weighting functions to achieve good H ∞ robust designs

The selection of the cost-weights in H_∞ cost-functions determines both performance and robustness properties. Guidelines are provided to aid the selection of weighting terms. The importance of both the noise weights and the cost function weights is emphasized. A procedure to ensure the system has adequate gain at low frequency and low gain at high frequency is suggested. The generalized cost-function is also compared with that of the more usual criterion and shown to have similar properties when appropriate dynamic weighting terms are chosen