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 measurements paths. The 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 effectivenesss of the porposed method, indices, and algorithm was investigated through simulations and experiments of kinematic calibration with an experimental in-parallel actuated worktable which we developed.