US Patent No. 9,367,045

SERVO CONTROL SYSTEM FOR GRINDING INCLINED SURFACE


Patent No. 9,367,045
Issue Date June 14, 2016
Title Servo Control System For Grinding Inclined Surface
Inventorship Naoto Sonoda, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,367,045

1. A servo control system for controlling a servo motor of a machine tool for grinding an inclined surface of a material to
be ground by a grindstone, the servo control system comprising:
a first servo motor configured to swing one of the grindstone and the material to be ground along a first swing shaft;
a first position detection unit configured to detect a position of the first servo motor;
a first servo motor control unit configured to control the first servo motor;
a second servo motor configured to swing the one of the grindstone and the material to be ground along a second swing shaft
perpendicular to the first swing shaft;

a second position detection unit configured to detect a position of the second servo motor;
a second servo motor control unit configured to control the second servo motor;
a reference angle calculation unit configured to calculate a reference angle based on a command angular speed and a command
distribution cycle acquired from processing conditions;

a swing command calculation unit configured to calculate a cyclical swing command based on the processing conditions and the
reference angle;

a first supply unit configured to supply the reference angle and the swing command to the first servo motor control unit;
a first position error calculation unit configured to calculate a first position error between the swing command and the position
of the first servo motor detected by the first position detection unit for each sampling cycle;

a first repeat control unit configured to execute repeat control for the first servo motor based on the reference angle, the
swing command, and the first position error;

a multiplication unit configured to multiply the swing command by a ratio according to a tilt angle of the inclined surface
of the material to be ground to calculate a swing command after multiplication;

a second supply unit configured to supply the reference angle and the swing command after multiplication to the second servo
motor control unit;

a second position error calculation unit configured to calculate a second position error between the swing command after multiplication
and the position of the second servo motor detected by the second position detection unit for each sampling cycle; and

a second repeat control unit configured to execute repeat control for the second servo motor based on the reference angle,
the swing command after multiplication, and the second position error,

wherein the first repeat control unit and the second repeat control unit respectively correct the first position error and
the second position error, and control driving of the first servo motor and the second servo motor based on the corrected
first position error and the corrected second position error, thereby grinding the inclined surface of the material to be
ground.