US 11,886,205 B2
Servo motor controller
Daisuke Tajima, Yamanashi (JP); Yuuki Morita, Yamanashi (JP); and Tadashi Okita, Yamanashi (JP)
Assigned to FANUC CORPORATION, Yamanashi (JP)
Filed by FANUC CORPORATION, Yamanashi (JP)
Filed on Jul. 9, 2020, as Appl. No. 16/924,599.
Claims priority of application No. 2019-128299 (JP), filed on Jul. 10, 2019.
Prior Publication US 2021/0011498 A1, Jan. 14, 2021
Int. Cl. G05D 13/62 (2006.01); G05D 3/12 (2006.01); G01D 5/347 (2006.01); G01D 5/12 (2006.01)
CPC G05D 13/62 (2013.01) [G05D 3/125 (2013.01); G01D 5/12 (2013.01); G01D 5/3473 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A servo motor controller that detects Z-phase signals of an incremental-type encoder that detects rotation of a servo motor to perform driving control of the servo motor, comprising:
a position detection unit that detects a reference position of a rotating shaft of the servo motor on the basis of the Z-phase signal of the encoder;
a signal interval detection unit that measures intervals of a plurality of detected Z-phase signals;
an abnormality determination unit that determines that the Z-phase signal is abnormal when the interval measured by the signal interval detection unit is equal to or larger than a prescribed threshold; and
a speed changing unit that changes a speed of the servo motor, wherein
the speed changing unit changes the speed of the servo motor when the abnormality determination unit determines that the Z-phase signal is abnormal.