In each step of the sequential design, an individual controller is designed by the robust frequency response approximation design procedure, the controller order is reduced by a frequency response approximation method.

• 在序列控制器设计的每一步 ；单个鲁棒控制器用鲁棒频域响应近似法获得 ；并使用频域响应近似法进行控制器降阶 .