A DBB-based kinematic calibration method for in-parallel actuated mechanisms using a Fourier series

For kinematic calibration of robots, we proposed using a low order Fourier series obtained by transforming the data for circular measurement paths. The errors of the realized paths were measured using a Double-Ball-Bar (DBB) system. Two nondimensional indices were proposed for evaluating the orthogonalities of the measurement paths and calibration parameters. An index was also proposed to evaluate the accuracy of the calibration with regard to measurement error An algorithm for determining adequate measurement paths and an optimal set of a specified number of paths using these indices was also proposed. The effectiveness of the proposed method, indices, and algorithm was investigated through simulations and experiments with an experimental 6 dof in-parallel actuated worktable that we developed.