Spatial four-degree-of-freedom parallel mechanism capable of three-dimensional translation and one-dimensional rotation

Abstract

A spatial four-degree-of-freedom parallel mechanism capable of three-dimensional translation and one-dimensional rotation is composed of a fixed platform, a movable platform and four same branched chains used for connecting the fixed platform with the movable platform. The branched chains include two types, wherein the first type is formed by six components in a connecting mode of R-R-2R=2R-R-R (R refers to a revolute pair, - refers to the components, and = refers to a pair of member bars which are parallel and equal in length), the second type is formed by four components in a connecting mode of R-2U=2U-R (R refers to a revolute pair, - refers to the components, = refers to a pair of member bars which are parallel and equal in length, and U refers to a Hooke joint). Each branched chain is driven by a servo motor firmly tied to the fixed platform. The four-degree-of-freedom parallel mechanism is simple in structure, easy for the mechanism to find forward and inverse solutions, convenient to control, good in mechanism rigidity, small in inertia and good in dynamics performance; in addition, the drive motors can be disposed on the fixed platform, and the member bars can be made into light bars, so that mechanism weight can be effectively reduced.

Description

technical field [0001] The invention relates to a four-degree-of-freedom parallel mechanism in three-dimensional translation and one-dimensional rotation space. Background technique [0002] Patent US.4976582 discloses a three-dimensional translation and one-dimensional rotation space four-degree-of-freedom parallel mechanism, which uses three external rotation pairs to drive and a parallelogram branch chain structure to achieve high-speed three-dimensional translation of the end effector, while still moving A retractable shaft with Hooke hinges at both ends is set between the platforms to realize the single-degree-of-freedom rotation of the end effector. However, the mechanism uses a telescopic rod structure in the process of realizing the rotation of the end effector, which will affect the rigidity and life of the high-speed motion mechanism; the paper "H4: a new family of 4-dofparallel robots", the paper "Par4-very high speed parallel robot for pick-and-place”、专利US200900...

AI Technical Summary

Problems solved by technology

However, the four-degree-of-freedom motion of the end effector of this type of mechanism is realized by the relative motion between the end members of the four branch chains. This structure will affect the rigidity of the parallel mechanism.

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