Accuracy improvement studies for remote maintenance manipulators

For ITER or the future DEMO remote maintenance system (WPRM), several types of special tailored automatic manipulators are needed for vacuum vessel (VV) component transportation, inspection, and removal from and replacement to the VV wall. Due to the extreme work conditions such as big size, big payload and high environment temperature, both the static and dynamic error sources should be considered when design a controller. In this paper, the accuracy improvement issues regarding the static and dynamic error sources are taken into account. The paper proposed a plane constraint calibration method for static error calibration, whilst the dynamic errors are calibrated using a linear inverse dynamic error model. Differential Evolution global optimization method was used to generate optimal excitation trajectories, and to identify the static and dynamic parameter errors. A 6-DOF (degrees of freedom) commercial industrial serial robot was employed to carry out the corresponding simulation and experimental studies. This paper mainly focuses on the general case studies, the results found in this research would be extrapolated to support the ITER or the future DEMO remote handling systems. (C) 2017 The Author(s). Published by Elsevier B.V.