Abstract
Background: Compared with the traditional series mechanism, the parallel mechanism has a better kinematic performance. Structural size error is the main factor affecting the accuracy of parallel mechanisms.
Objective: The paper mainly studies the compensation of the rod length error, the moving platform radius error and the fixed platform radius error of 3-UPU parallel mechanism.
Methods: To establish a generalized forward and inverse solution equation with error compensation, the position change of the moving platform is measured by a laser interferometer, and the change amount of the three connecting rod lengths at the corresponding position is recorded. Optimized by least squares method, the optimized error compensation values are compensated to the kinematics algorithm of the numerical control system, and the positioning accuracy is improved.
Results: The results show that the positioning accuracy is higher when the mechanism moves in the lower plane, and the positioning error in the z axis direction is smaller than x, y, y=x, y=-x axis.
Conclusion: After the error compensation, the overall positioning accuracy of the mechanism is increased by 60%.
Keywords: 3-UPU parallel mechanism, error compensation, generalized forward and inverse solution, kinematics, least squares method, positioning accuracy.
Graphical Abstract
[http://dx.doi.org/10.1007/s00170-017-0590-9]
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[http://dx.doi.org/10.1109/ACCESS.2018.2878976]
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