Six-degree-of-freedom parallel mechanism with measurement standard and fixed coordinate system

Abstract

The invention discloses a six-degree-of-freedom (DOF) parallel mechanism with a measurement standard and a fixed coordinate system. The mechanism is characterized in that: the crossing point of the central lines of positioning holes of two rotary shafts of a Hooke hinge is a rotary center of the Hooke hinge, the rotary center and a positioning hole on a bottom plate have a determined position relationship, and the position of the rotary center of the Hooke hinge can be obtained by measuring the positioning hole. A method for establishing the measurement standard for direct measurement by leading out characteristic points of the parallel mechanism can well effectively solve the measurement problem of the characteristic points, and improves the moving precision and the positioning precision of the parallel mechanism. The advantage of successfully applying a parallel mechanism simulator for simulating a butting process in the manned space flight project is obtained.

Description

technical field [0001] The invention relates to the technical field of precision measurement of a six-degree-of-freedom motion mechanism, in particular to a six-degree-of-freedom parallel mechanism with a measurement reference and a fixed coordinate system. Background technique [0002] At present, the motion accuracy and positioning accuracy of the known six-degree-of-freedom parallel mechanism are related to the mutual positional accuracy of some feature points of the mechanism, and usually only rely on processing and assembly to ensure these mutual positional relationships, and most of these feature points are invisible and intangible , some feature points can only appear when the parallel mechanism moves, and it is the spatial position relationship. [0003] These feature points mainly include: "the accuracy of the distribution circles where the centers of rotation of the six upper Hooke hinges are located, the accuracy of the distribution circles where the six lower Hoo...

AI Technical Summary

Problems solved by technology

Due to the limitations of existing technologies, the six-degree-of-freedom parallel mechanism relies on processing and assembly to ensure the spatial position relationship of feature points, and there is a certain degree of blindness that cannot be guaranteed and effectively controlled. Moreover, the parameters of this type of parallel mechanism are mutually involved and coupled. It is difficult to detect, especially the accuracy of large-scale parallel mechanisms is even more difficult to guarantee. Consult literature reports: It is learned that an error compensation method can be used to improve the accuracy of parallel mechanisms, that is, when the parallel mechanisms move to different six-degree-of-freedom spatial positions , measure the spatial positions of several identical points in the parallel mechanism, and then calculate the position of the feature points through a large number of Jacobian matrix solutions and multiple iterations. This method is undoubtedly very complicated and the repeatability is not high.

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