A simple derivation of are solutions to the standard H∞ control problem based on LMI solution

In this paper, a simple derivation of the Riccati equation based solutions to the standard H
∞
control problem, namely the well-known Glover-Doyle solution and DGKF solution is given based on LMI solution. It is hoped that this will be helpful for ordinary control engineers in deepening the understanding of Riccati equation solutions.