Robot calibration

• US 4,753,569 A
• Filed: 08/08/1986
• Issued: 06/28/1988
• Est. Priority Date: 12/28/1982
• Status: Expired due to Term

• Current Assignee: LMI Technologies Inc.
• Original Assignee: Diffracto, Ltd. (LMI Technologies Inc.)
• Inventors: Pryor, Timothy R.
• Primary Examiner(s): Spar, Robert J.
• Assistant Examiner(s): Doyle, Jennifer
• Application Number:
  US06/894,721
• Time in Patent Office: 690 Days
• Field of Search: 414/730, 901/9, 901/46, 901/47, 250/203, 250/227, 358/107, 358/903, 364/559, 356/152
• US Class Current: 700/250
• CPC Class Codes: A01B 69/008 automatic
• CPC Class Codes: B23P 19/10 Aligning parts to be fitted together
• CPC Class Codes: B25J 19/021 Optical sensing devices
• CPC Class Codes: B25J 19/023 including video camera means
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: G05B 2219/39057 Hand eye calibration, eye, camera on hand, end effector

Abstract

A method and apparatus for calibrating a computer guided robotic apparatus. At least one camera mounted on the robot arm or fixed at the work station views a target comprising a pattern of at least three dots fixed to the other of the robot arm or work station, such viewing taking place as the robot arm approaches the work station to carry out the intended operation. The sensing of any deviation relative to a predetermined target pattern is transmitted to the computer to reset the robot'"'"'s computerized guidance system.

Claims

1. In combination,

a robotic apparatus, having an arm and an operative end, for automatically handling or working on an object at a work station;

a computerized guidance means for controlling movements of the arm and operative end for carrying out an intended handling or working on the object at the work station, said guidance means also serving to move the arm and operative end to a predetermined location immediately adjacent to the work station;

calibration means for checking and if necessary resetting the computerized guidance means, said calibration means comprising means for sensing the position of the arm and operative end, independently of the guidance means, when the arm and operative end are at the predetermined location immediately adjacent to the work station, and signal means for generating an actual position calibration signal, said sensing means comprising at least one target mounted in the vicinity of the predetermined location of the work station and being mounted independently of the arm and operative end, and at least one camera means for imaging said target from the arm and operative end along a predetermined and fixed line of sight, said camera means comprising a camera device located remote from the arm and operative end and fiber optics located on the arm and operative end for viewing said target and for communicating with the camera device;

means for comparing the actual position calibration signal against a reference position signal generated by said computerized guidance means and for noting any deviation therebetween; and

means for resetting the computerized guidance means in response to said deviation.

2. The invention of claim 1, including a plurality of cameras positioned to view a single target.

3. The invention of claim 1, said target comprising a pattern of at least three dots or other features positioned to be viewed by the camera to ascertain the position of the arm and operative end in the X, Y, Z, pitch, roll and yaw directions.

4. The invention of claim 3, said target including four dots arranged in a rectangular pattern.