US Patent No. 9,334,911

SERVO CONTROLLER HAVING FUNCTION FOR REDUCING DROPPING WHEN BRAKING


Patent No. 9,334,911
Issue Date May 10, 2016
Title Servo Controller Having Function For Reducing Dropping When Braking
Inventorship Kouki Kameta, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,334,911

1. A servo controller for controlling a servomotor which drives a gravity axis of a machine tool or an industrial machine,
the servo controller comprising:
a brake signal outputting part configured to output a brake activation signal and a brake release signal to a mechanical brake
with a backlash for holding the gravity axis;

a torque command generating part which generates a torque command value for controlling a position of the servomotor; and
a torque limiting value generating part which generates a torque limiting value for limiting the torque command value generated
by the torque command generating part,

wherein the torque limiting value generating part continuously reduces the torque limiting value from a first value larger
than a torque corresponding to a gravity force to a second value smaller than the torque corresponding to the gravity force,
after the brake signal outputting part outputs the brake activation signal.