Determination of Linkage Parameter and Pair Variable Errors in Open Chain Kinematic Linkages Using a Minimal Set of Pose Measurement Data

During the manufacture of robotic systems differences between actual and nominal link lengths and orientations occur. In addition, errors between nominal and actual pair variables result from sensor and controller errors. Thus, when a robotic system attempts to perform a desired task using nominal motion planning schemes and nominal linkage kinematics, it will perform an actual task that is usually quite different from that desired. A procedure for determining the differences between the nominal and actual linkages parameters, pair variables, and tasks is presented. The approach can be used on all modern-day robots, as it incorporates solution techniques for the nonsquare and singular matrices that typically occur. An example using a PUMA 560 is included.