Okuma Corporation

Takeshi Sakai

Yuji Uchida

Tomohiro Shibata

Masashi Miyaji

Akiyoshi Satake

Hisashi Kondou

Ai Kojima

A motor control device includes an abnormality determination unit that determines the presence of any abnormality in a current detector. The abnormality determination unit includes, for example, a U-phase abnormality determination device. The U-phase abnormality determination device calculates, as a voltage command threshold, a value obtained by adding a dead time voltage error, which is a voltage error occurring due to a dead time, to an ideal voltage command threshold, which is a value obtained by multiplying a prescribed reference current value by a motor resistance value, and outputs a signal indicating an abnormality in the current detector when the effective value of a voltage command value is equal to or greater than the voltage command threshold and the effective value of a current detection value is equal to or less than a current detection threshold that is lower than the reference current value.

Motor control device and abnormality detection method for current detector provided in motor control device

A position control apparatus includes an inversion detector which detects an inversion of a position command and generates an inversion detection signal, a deflection characteristic storage unit which stores a deflection characteristic representing an amount of deflection with respect to a torque command, and an inversion correction calculator which calculates an inversion correction amount. The inversion correction calculator stores a torque command immediately before the inversion, and calculates the inversion correction amount from a difference between an amount of deflection immediately before inversion in which the stored torque command is checked with the deflection characteristic, and an amount of deflection after the inversion in which a value obtained by inverting a sign of the stored torque command is checked with the deflection characteristic. A value obtained by adding the inversion correction amount to the position command value is used for position error calculation.

Position control apparatus

A compensation function constituting device calculates a correlation coefficient based on a moving distance required for reversing a moving direction of a movable unit and a sliding resistance acting on the movable unit, and a compensation amount output device calculates a moving distance on a position command value required until the movable unit starts to move according to the correlation coefficient and a feedback torque when the moving direction is reversed and increases a torque compensation amount in accordance with the moving distance after reversing the moving direction until the moving distance after the moving direction is reversed reaches the moving distance required until the movement is started.

Position control device

An electric motor control device for performing tandem control for driving one movable component includes, for each electric motor, a position controller, a speed controller, and a current controller. Further, each electric motor also has a preload controller for adding a preload torque to a torque command Tm calculated by the speed controller, and to a torque command Ts calculated by the speed controller. The preload controller calculates a minimum necessary preload torque for eliminating backlash in accordance with a position of the movable component.

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Niwa-gun Aichi, Japan

Takeshi Sakai