Abstract
The purpose of the present paper is to propose a new design method of low order Two-Degree-of-Freedom (TDF) controllers. In general, the TDF controller design is conducted with the sequential approaches in which a feedback controller and a feedforward controller are designed one by one. As a result, in these approaches, it is not easy to design the low order TDF controllers which take advantages of the freedom in TDF con-troller. In this paper, a simultaneous design method of the feedfoward controller and the feedback controller is proposed. Not only H∞ norm optimization problem but also H2/H∞ mixed norm optimization problem can be utilized to design Two-Degree-of-Freedom control system via Linear Matrix Inequality approach. The advantages of the proposed method over the sequential approaches are as follows: (1) controllers which share common dynamics can naturally be derived in this method, (2) the trade-off between the feedback perfor-mance and the target-following performance and the order of the controller can easily be considered in a one-step design process.
