Abstract: The module level parameter calibration method for modular reconfigurable robot is studied. The twist exponential map is taken to describe the joint module, link module, the assembly orientation between tow modules and the sub-assembly composed of a joint module and a link module; the kinematic modeling methods both in module level and sub-assembly level for modular robot are given. The errors in modules, sub-assemblies and manipulators are analyzed. The error model between the sub-assemblies and manipulator is given, the combined calibration model and its procedure considering the information of the structures of multiple manipulators is presented. The error model between modules and sub-assembly is given, the combined calibration model and its procedure considering multiple sub-assemblies is presented. Based on the two combined calibration models, a tow-level iterative method for module parameter calibration which can compensate the pose errors of multiple manipulators is presented. The simulation result shows that the calibration method is stable, and the calibration results can achieve the pose accuracy compensation of multiple manipulators effectively.

Key words: Modular reconfigurable robot, Parameter calibration, Product of exponential