US Patent No. 9,423,785

TOOL TRAJECTORY DISPLAY DEVICE HAVING FUNCTION FOR DISPLAYING INVERSION POSITION OF SERVO AXIS


Patent No. 9,423,785
Issue Date August 23, 2016
Title Tool Trajectory Display Device Having Function For Displaying Inversion Position Of Servo Axis
Inventorship Junichi Tezuka, Yamanashi (JP)
Hajime Ogawa, Yamanash (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,423,785

1. A tool trajectory display device for displaying a trajectory of a tool center point of a machine tool with a plurality
of servo axes including at least one rotation axis controlled by a numerical controller, the tool trajectory display device
comprising:
a position information obtaining part which obtains position information of at least one servo axis of the plurality of servo
axes, by using a position detector which measures the position of the at least one servo axis;

a velocity information obtaining part which obtains velocity information of the at least one servo axis, by calculating the
velocity information based on the position information obtained by the position information obtaining part or by using a velocity
detector which measures a velocity of the at least one servo axis;

a tool coordinate calculating part which calculates a coordinate value of the tool center point based on the position information
of the at least one servo axis and information of a mechanical constitution of the machine tool;

an inversion position calculating part which calculates a plurality of inversion positions based on the velocity information
of the at least one servo axis and the coordinate value of the tool center point, the plurality of inversion positions including

a first inversion position where a polarity of the velocity of the at least one servo axis is changed from plus to minus,
and

a second inversion position where the polarity of the velocity of the at least one servo axis is changed from minus to plus;
and

a displaying part which
displays a trajectory of the tool center point based on the coordinate value of the tool center point, and
displays the plurality of inversion positions of the at least one servo axis on the trajectory of the tool center point,
wherein the plurality of servo axes includes a gravity axis, and the displaying part displays the first and second inversion
positions by using different display attributes, respectively, to indicate whether a moving direction of the gravity axis
is changed from upward to downward or from downward to upward, for evaluating an effect of gravity on a shape error of a workpiece
to be processed by the machine tool.