Kinematic error calibration of the Gantry-Tau parallel manipulator

This paper presents a new error kinematic model containing twelve parameters for the three linear actuators of the Gantry-Tau parallel kinematic manipulator. Three different types of measurement equipment, laser interferometers, linear encoders and double-ball bars, can successfully be used to calibrate the linear actuators. A method for selecting an optimal set of Cartesian coordinates is presented and a small set of fifty coordinates have been found to be sufficient. The methods presented in this paper allow for a fast and easy set up calibration procedure of the Gantry-Tau after assembly and installation, which is a pre-requisite for flexible automation with parallel kinematic manipulators