Vibration isolation controller design by frequency shaping with pole placement constraints

We consider a vibration isolation control problem in a case of which the narrow-band frequency disturbances are applied to a system. The frequency shaping method by the H_∞ control is a helpful method for the problem. However, constraints of closed-loop poles cannot be applied to the method as an additional specification. This is because the poles of weighting functions become undetectable modes of the generalized system in the H_∞ design. In order to overcome this problem, a design method by combination of the extended H_∞ control and the robust stability-degree assignment method is proposed. By this method, we can design a controller which provides desirable frequency shaping and preferable closed-loop pole location at the same time. Performance of the designed controller is demonstrated by experiments and we confirmed that it provides expected vibration isolation performance.