H/sub /spl infin// control synthesis via reduced order LMIs

In H/sub /spl infin// control synthesis for systems with weighting functions, linear matrix inequality (LMI)-based approaches face heavy computation and possibly numerical ill-conditioning. In this paper, a new formulation is presented to find a full order controller via reduced order LMIs and fewer decision variables, by exploiting the potential pole-zero cancellation in the closed loop. As a result, both numerical conditioning and numerical efficiency are improved. An interesting application of the results to servomechanism problems is also given.