Tool center point calibration apparatus and method

DETAILED DESCRIPTION The present invention provides a tool center point calibration unit for a robot.
The tool center point calibration unit includes a frame positioned within the robot envelope.
A tool center point calibration device is supported on the frame with the calibration device having a centerline positioned along a single line.
The tool center point calibration device generates a signal adapted to indicate when the tool tips are at the centerline.
The calibration device may be positioned substantially parallel to a robot axis and may be positioned such that the robot is adapted to reach the calibration device with a tool tip axis substantially parallel to one of the robot axes.
In one embodiment of the present invention, the calibration device is a single beam.
In this embodiment the frame is preferably a base with a post extending from the base and a pair of spaced arms extending from the post to the single beam, wherein the single beam extends between the pair of spaced arms.
A fiber-optic cable may be supported within the frame to generate the single beam.
The present invention includes a method for tool calibration for a robot tool.
The method includes the steps of positioning a calibration device within the robot envelope, wherein the calibration device includes a beam having a centerline positioned along a single line.
The tool tip is positioned to an initial position within the path of the beam.
Values of the robot face plate are obtained with the tool tip at the initial position within the beam path.
The tool is rotated about the axis of the tip to at least a second position with the tool tip positioned within the beam path.
Additional values of the robot face plate with the tool tip at the subsequent position(s) are obtained and a tool center point is calculated based upon the obtained values.
The tool may then be aligned based upon the calculated tool center point.
Alternatively, the robot can automatically adjust the movement of the tool in operation to account for the new tool center point