| 摘要 |
PURPOSE:To enable a linear motor to be stopped at a given position, by a method wherein the rotation of the phase excited by a propulsive winding is stopped as well as DC excitation is carried out before stopping the linear motor. CONSTITUTION:A position signal pds sent by means of wireless from a position detector PD on a traveling body TR, which is a square wave having an electrical angle of 180 deg., is inputted in three-phase manner. A velocity calculating device VCD calculates a velocity V on the basis of the interval between the rising time and falling time of the position signal pds while a synchronous controller SYC outputs a sine wave SW corresponding to the velocity V in synchronization with the rise and fall of the position signal pds. A current pattern generator IPG determines a current pattern iP from the sine wave SW and a current command iS. In stopping, after the velocity V has become a set low speed, the phase rotation is stopped when the position signal pds coincides with the phase set by a stop phase setter SPS. Until the linear motor is stopped after stoppage of the phase rotation, one- or two-phase excitation is carried out. |
