Passive gravity compensation branched chain of spatial parallel mechanism

Abstract

A passive gravity compensation branched chain of a spatial parallel mechanism comprises a balance weight, a bisynchronous telescope branched chain, a middle Hooker hinge and a spherical hinge, wherein the middle section of an external bar of the bisynchronous telescope branched chain is connected with a fixed platform of the spatial parallel mechanism through the middle Hooker hinge; the rotating center of the middle Hooker hinge coincides with the geometric center of the fixed platform; the balance weight is fixedly connected with one end of the bisynchronous telescope branched chain; the other end of the bisynchronous telescope branched chain is connected with a movable platform of the spatial parallel mechanism through the spherical hinge; the centroid of the middle Hooker hinge, the rotating center of the middle Hooker hinge and the rotating center of the spherical hinge are collinear; and the distance between the centroid of the balance weight and the rotating center of the middle Hooker hinge is the same as that between the rotating center of the spherical hinge and the rotating center of the middle Hooker hinge. Through the adoption of the passive gravity compensation branched chain, the branched chain static driving force generated by the gravity is eliminated, and the passive gravity compensation branched chain is simple in structure, reasonable in layout, and convenient to use, does not need a driving unit, reduces the branched chain driving force of the spatial parallel mechanism, improves the efficiency and the dynamic characteristics of the mechanism, and is favorable for fully giving play to the advantage of the potential performance of the spatial parallel mechanism.

Description

technical field [0001] The invention relates to the technical field of gravity compensation of a space parallel mechanism, in particular to a passive gravity compensation branch chain of a space parallel mechanism. Background technique [0002] The parallel mechanism has the advantages of large load-to-mass ratio and high rigidity, and is widely used in heavy-duty working conditions. The static driving force of the branch chain generated by gravity is relatively large, resulting in problems such as bulky mechanism structure and high power consumption of the driving unit. The complete gravity compensation can completely eliminate the static driving force, effectively reduce the driving force of the branch chain, and improve the dynamic performance of the mechanism. [0003] At present, there are mainly three methods for complete gravity compensation of parallel mechanisms: (1) Gravity compensation methods that completely rely on adjusting the mass distribution of parallel me...

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Problems solved by technology

[0003] At present, there are mainly three methods for complete gravity compensation of parallel mechanisms: (1) Gravity compensation methods that completely rely on adjusting the mass distribution of parallel mechanisms or changing the branch chain structure: this method puts strict requirements on the quality of the mechanism or the branch chain structure, Difficult to apply and cannot be adjusted accordingly to load

(2) Active gravity compensation branch chain: This method requires additional driving components, and there is a problem of redundant driving, which makes the control complicated

(3) Passive compensation branch chain based on parallelogram structure: the structure of the passive compensation device is complicated, the cost of manufacturing and installation is high, and the space rigidity is limited

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