| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 104 === Manufacturing errors and assembling errors are two of the most important factors that affect the accuracy of a parallel manipulator. Upgrading the machining and assembling process, in theory, can reduce the errors, but the cost of a manipulator can significantly increase. Therefore, the approach of finding the real dimensions by calibration methods is commonly used to improve the accuracy of a manipulator.
There are two types of calibration: self-calibration and traditional -calibration. Self-calibration needs extra sensors or imposes some physical constraints on the passive joints, so it is more complicated and expensive to develop a self-calibration manipulator. Besides, there are more parameters to be calibrated. Traditional-calibration measures different positions and orientations of the moving platform and then determines the real link dimensions of a manipulator by solving a system of nonlinear equations.
This thesis proposes methods to calibrate three types of parallel manipulators: 6-DOF Stewart manipulators, 6-DOF Delta manipulators and 3-DOF Delta manipulators. The calibration results are evaluated using direct and inverse kinematics. It shows that the accuracy of the manipulator with the new dimensions is significantly improved. The effect of coupling of the variables in related equations is studied, and how to design a manipulator that is easier to be calibrated is also investigated.
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