US Patent No. 9,356,550

MOTOR CONTROLLER HAVING ABNORMALITY DETECTION FUNCTION OF POWER TRANSMISSION UNIT BETWEEN MOTOR AND MAIN SHAFT


Patent No. 9,356,550
Issue Date May 31, 2016
Title Motor Controller Having Abnormality Detection Function Of Power Transmission Unit Between Motor And Main Shaft
Inventorship Daisuke Tajima, Yamanashi (JP)
Tadashi Okita, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,356,550

1. A motor controller which controls the rotation drive of a motor in which a rotational power is transmitted to a main shaft
via a power transmission unit, comprising:
a motor rotation angle acquisition unit acquiring the rotation angle of the motor;
a main shaft rotation angle acquisition unit acquiring the rotation angle of the main shaft;
a one-rotation signal acquisition unit acquiring a one-rotation signal output every time the main shaft rotates once;
a motor rotation speed calculation unit calculating the rotation speed of the motor from the acquired rotation angle of the
motor;

a main shaft speed calculation unit calculating the rotation speed of the main shaft from the acquired rotation angle of the
main shaft;

a first temporary determination unit in which, when a change amount of the rotation angle of the motor acquired between the
time when a one-rotation signal is acquired and the time when the next one-rotation signal is acquired deviates from a first
range, it is temporarily determined that an abnormality has occurred in the power transmission unit;

a second temporary determination unit in which, when the difference between the rotation speed of the motor and the rotation
speed of the main shaft deviates from a second range, it is temporarily determined that an abnormality has occurred in the
power transmission unit; and

an abnormality determination unit in which, when at least one of the first temporary determination unit and the second temporary
determination unit temporarily determines that an abnormality has occurred in the power transmission unit, it is determined
that an abnormality has occurred in the power transmission unit.