Automatic Kinematic Calibration of a Modular Gantry-Tau Parallel Robot from a Kinematics Point of View

A method for computer assisted kinematic calibration of a modular Gantry-Tau parallel robot is presented and tested in an experiment. A computer tool developed executes the first step of a kinematic calibration, the choice of appropriate measurement points, using a priori knowledge about kinematic parameters, e.g. obtained with a measuring tape. This step is performed by intersecting the robot's kinematic workspace and the area surveyable by the measurement device and overlaying it with a grid of a desired number of measurement points. A simulation determines automatically whether the choice leads to an accurate calibration and outputs a trajectory readable by a robot controller. In a calibration experiment it is shown that the method gives results with an accuracy comparable to that of manual calibration. The method allows non-experts to execute kinematic calibration of modular robots after reconfiguration thus making possible the use of modular robots in small size enterprises where such robots can answer the need for flexibility required with regularly changing tasks.