Robot zero-point calibration device and method
A robot zero-point calibration device includes an axial position recording unit configured to record positional data of each axis of a robot in each of a plurality of postures when a first positioning point and a second positioning point are made to coincide with each other, the first positioning point being disposed at a predetermined coordinate on a base coordinate system of the robot, and the second positioning point being disposed at a predetermined coordinate on a flange coordinate system of the robot. The device also includes a positional offset calculating unit configured to calculate an offset amount of a zero point of each axis of the robot from a true zero point of the axis based on a plurality of sets of the positional data stored in the axial position recording unit.
1. A robot zero-point calibration device, comprising:
an axial position recording unit configured to record positional data of each axis of a robot in each of a plurality of postures when a first positioning point and second positioning point are made to coincide with each other, the first positioning point being disposed at a predetermined coordinate on a base coordinate system of the robot, and the second positioning point being disposed at a predetermined coordinate on a flange coordinate system of the robot; and
a positional offset calculating unit configured to calculate an offset amount of a zero point of each axis of the robot from a true zero point of the axis based on a plurality of sets of the positional data stored in the axial position recording unit, wherein
the positional offset calculating unit is configured to calculate
coordinates of the second positioning point on the base coordinate system from a set of positional data in each of the plurality of postures and the predetermined coordinate of the second positioning point on the flange coordinate system,
differences between the coordinates of the each of the second positioning point on the base coordinate of the predetermined coordinate of the first positioning point, and
an offset amount of each axis based on a plurality of the calculated differences.
2. The robot zero-point calibration device according to claim 1 , wherein
the robot is a seven-axis robot, and
the axial position recording unit records the positional data of each axis of the robot when the first positioning point is made to coincide with the second positioning point while the robot is in three postures or more.
3. The robot zero-point calibration device according to claim 1 , further comprising:
a first calibration jig fixed to a base of the robot to provide the first positioning point; and
a second calibration jig fixed to a wrist flange of the robot to provide the second positioning point.
4. The robot zero-point calibration device according to claim 3 , wherein
the first calibration jig includes a first tip at the first positioning point, and
the second calibration jig includes a second tip at the second positioning point.
5. The robot zero-point calibration device according to claim 3 , wherein
the first calibration jig is provided with three measurement targets measurable by a three-dimensional measurement device, and
the second calibration jig is provided with one measurement target measurable by the three-dimensional measurement device.
6. The robot zero-point calibration device according to claim 3 , wherein
the second calibration jig includes a camera, and
the first calibration jig is provided with a geometric characteristic measurable by the camera.
7. A robot zero-point calibration method, comprising:
making a first positioning point and a second positioning point coincide with each other in each of a plurality of postures, the first positioning point being disposed at a predetermined coordinate on a base coordinate system of a robot, and the second positioning point being disposed at a predetermined coordinate on a flange coordinate system of the robot;
recording positional data of each axis of the robot when the first positioning point and the second positioning point are made coincide with each other while the robot is in each posture at the positioning step; and
calculating an offset amount of a zero point of each axis of the robot from a true zero point of the axis based on a plurality of sets of the positional data stored at the axial position recording step, wherein
the calculating of the offset amount includes
calculating coordinates of the second positioning point on the base coordinate system from a set of positional data in each of the plurality of postures and the predetermined coordinate of the second positioning point on the flange coordinate system,
calculating differences between the coordinates of the each of the second positioning point on the base coordinate system and the coordinates of the predetermined coordinate of the first positioning point, and
calculating the offset amount of the each axis based on a plurality of the calculated differences.
8. The robot zero-point calibration method according to claim 7 , wherein
the robot is a seven-axis robot, and
the axial position recording step records the positional data of each axis of the robot when the first positioning point is made to coincide with the second positioning point while the robot is in three postures or more.