抄録
The purpose of this study is to realize a magnetic bearing of nanometer rotational accuracy at a high speed. Unbalance force which arises from non-coincidence of the center of rotation and the center of inertia in a spindle decreases the rotational accuracy. The spindle motion control around the center of inertia is desirable for decreasing the unbalance force. In this paper, first, a method for estimating the center of inertia from currents of electromagnets is proposed. Then the spindle is experimentally controlled to rotate around the estimated center of inertia. Experimental results show that the rotational accuracy of the spindle is 13.3nm (3σ) at 2000 min_<-1>, and the electromagnetic control force which synchronizes with the spindle rotation is suppressed to 0.19N which is 6.7% of that around the center of profile.
