US 9,811,069 B2
Servomotor control apparatus
Kiyoshi Nakayama, Yamanashi (JP)
Assigned to FANUC CORPORATION, Yamanashi (JP)
Filed by FANUC CORPORATION, Yamanashi (JP)
Filed on Aug. 2, 2016, as Appl. No. 15/226,103.
Claims priority of application No. 2015-154161 (JP), filed on Aug. 4, 2015.
Prior Publication US 2017/0038748 A1, Feb. 9, 2017
Int. Cl. H02P 3/14 (2006.01); G05B 19/042 (2006.01)
CPC G05B 19/042 (2013.01) [G05B 2219/25023 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A servomotor control apparatus comprising:
one or more servomotors each for driving a movable portion of a machine;
an electromagnetic brake for maintaining the position of the machine;
a position detector for feeding back an actual position signal;
a servo amplifier for driving the servomotor;
a servo feed circuit for supplying electric power to the servo amplifier; and
a central processing unit for commanding and monitoring the servomotor, wherein
the servo feed circuit has an electromagnetic contactor for switching the supply of the electric power to the servo amplifier,
the central processing unit has a motor controller for generating a command position of the servomotor and issuing at least one of a motor torque command to maintain the position based on the generated command position and a regenerative brake operation command, an actual position monitor for periodically monitoring an actual position fed back from the position detector, and a feed circuit controller for controlling the supply of the electric power to the servo amplifier, and
in a state in which the servo amplifier is powered off and the electromagnetic brake is operated to maintain the position, when the actual position monitored by the actual position monitor is different from the actual position at the time of actuating the electromagnetic brake by a predetermined value or more, the electromagnetic contactor is closed to supply the electric power to the servo amplifier and the motor torque command is issued to maintain the position.