A completely decoupled two-rotation-one-shift three-degree-of-freedom parallel mechanism

Abstract

A complete decoupling type two-rotating, one-moving and 3-DOF (degree-of-freedom) parallel mechanism comprises a fixed platform, a movable platform, and three branch chains for connecting the two platforms, wherein an upper connecting rod and a lower connecting rod of the first branch chain are correspondingly connected with the movable platform and the fixed platform through a hook hinge and a rotating pair; the upper connecting rod and the lower connecting rod of the second branch chain are correspondingly connected with the movable platform and the fixed platform through a ball pair and another hook hinge; the upper connecting rod and the lower connecting rod of the third branch chain are connected to the movable platform and the fixed platform through rotating pairs; the upper connecting rod and the lower connecting rod of the three branch chains are connected through moving pairs; an axis of the rotating pair for connecting the third branch chain to the movable platform is overlapped with the axis of the hook hinge for connecting the first branch chain to the movable platform; the axis of the rotating pair for connecting the third branch chain to the fixed platform is parallel to the axis of the rotating pair of the first branch chain and is overlapped with the axis of the hook hinge for connecting the second branch chain to the fixed platform. According to the mechanism, few 1-DOF moving pairs are used, so that the structure stiffness is high; the input and the output are corresponding to each other, and thus the movement decoupling can be completely achieved; a control model is simple, and the practicability is high.

Description

technical field [0001] The invention belongs to the field of robots, in particular to a parallel mechanism. Background technique [0002] Since Hunt proposed the 3-RPS parallel mechanism in 1983, the two-rotation-one-shift three-degree-of-freedom parallel mechanism has received widespread attention and can be applied to motion simulators, coordinate measuring machines, spindle heads of machining centers, etc., among which the most typical application It is used as the spindle head of a parallel machine tool, and a two-degree-of-freedom rotary head is attached to the spindle head to realize the processing of complex parts in aerospace, automotive industry and other fields. The 3-RPS parallel mechanism does not have two continuous rotating shafts, and its kinematic equations are complex, making it difficult to realize control. The Tricept mechanism (3UPS-UP three-degree-of-freedom parallel mechanism) and other two-turn-one-shift parallel mechanisms with UP constrained branche...

AI Technical Summary

Problems solved by technology

The 3-RPS parallel mechanism does not have two continuous shafts, and its kinematic equations are complex, making it difficult to control

However, the above two-rotation-one-shift parallel mechanisms with two continuous shafts have strong kinematic coupling, that is, there is no simple one-to-one correspondence between motion input and output, and the control is difficult

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