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Method and apparatus for position control of an electric motor

  • US 4,558,265 A
  • Filed: 03/02/1983
  • Issued: 12/10/1985
  • Est. Priority Date: 03/03/1982
  • Status: Expired due to Term
First Claim
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1. A method of controlling a position of an electric motor with the aid of a rotation angle detector for detecting a rotation angle of a rotating shaft of said motor or a rotating shaft constituting a part of a power transmission path for operatively coupling said rotating shaft of said motor to an apparatus constituting a load, said rotation angle detector providing signals representative of the rotation angle and a rotating speed of said rotating shaft, and a control circuit for controlling said motor so that said motor is positioned at a given position in accordance with a position command signal issued to said motor in consideration of said rotation angle and said rotating speed,wherein a control process activated upon starting of said motor in response to said position command signal and ending upon stoppage of said motor at a position designated by said position command signal includes a first control region in which at least acceleration of said motor in an accelerating phase thereof is detected and subsequently a constant speed operation of said motor is effected at a maximum speed, a deceleration initiating time point determined on the basis of said acceleration, a second control region in which said motor is decelerated from said deceleration initiating time point in accordance with a deceleration pattern which is determined in dependence on a rotation angle between the deceleration initiating position and the commanded stop position, torque of said motor and magnitude of inertia of said load detected at the time point at which said deceleration is initiated, and a fifth control region in which said motor is held at the stop position designated by said position command signal.

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