1991 年 57 巻 540 号 p. 2554-2559
To reduce resonance vibrations of a flexible rotor suspended by active electromagnetic bearings, the state feedback control whose design is based on an approximate reduced-order model is effective. For a realization of this control, it is necessary to estimate unbalanced forces and usually an observer which estimates the entire state vector is used. But on the representation of the space state equation the elements of a coefficient matrix being function of rotational speed, the design of an observer is not simple. In this paper using an inverse system to estimate external forces with constant gain matrices, the design of the state feedback controller is presented which enables to improve modal damping of the mechanical system independently. In the experimental system applied above concept, a good estimation of external forces with an inverse system is achieved, and it is verified that the feedback control which relates modal velocities has a capability to improve damping properties of the mechanical system on each mode.