Manipulator calibration enhancement by means of mechanical templates

Machines assembly procedures usually make use of some kind of references (for instance mechanical templates, or some kind of artefact, or simply locators holes on machine table) in order to assure a precise end-effector positioning at least in the assembly position (also called, zero position or home position) [R. Ramesh, M.A. Mannan, Error compensation in machine tools – a review. Part I: geometric, cutting-force induced and fixture-dependent errors, International Journal of Machine Tools and Manufacture, 40 (9) (2000), 1235–1256]: then, such an accurate positioning is exploited during the set-up phase to perform actuators offsets compensation. This approach is usually adopted both for manipulators (above all Parallel Kinematic ones) and for Cartesian machine tools. In this short communication, a new calibration strategy is suggested in order to allow the exploitation of assembly positioning accuracy for an advantageous change of error parameters.