Robot Joint Linkage With Sliding Pivot for Wide Motion Range
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Solution Overview
Problem
Existing joint structures for robots, such as those described in Japanese Unexamined Patent Application Publication No. 2009-47299, have a limited range of motion of about 90° and are unable to achieve a wide range of motion while maintaining a deceleration effect in high-load postures.
Innovation Solution
A joint structure for robots that includes a first link connected to a first member, a second link connected to the first link and a second member, a first pivot connecting the first link to the second link, a third link connected near the first pivot to the first link, and a slide part on the second link that allows the third link to slide, enabling a wide range of motion and deceleration effect in high-load postures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a non-parallelogram link mechanism is used to achieve deceleration effect in high-load posture, then the torque capability is improved, but the range of motion is limited to about 90°
Solution Approach 1:
The mechanism is divided into multiple links (first link, second link, third link) connected by pivots, with each link serving a specific function in the deceleration mechanism. This segmentation allows the system to achieve both torque multiplication and extended range of motion through coordinated movement of discrete components.
Solution Approach 2:
The mechanism introduces a slide part that adds a linear motion dimension to the rotational motion of the links. This dimensional transformation allows the third link to extend beyond the traditional 90° rotation limit while maintaining the deceleration effect through the combined rotational and translational degrees of freedom.
2Ease of operation
If the joint structure is simplified to increase range of motion, then the ease of operation is improved, but the deceleration effect in high-load posture is lost
Solution Approach 1:
The mechanism dynamically adjusts the deceleration ratio based on the joint's posture through the variable transmission ratio inherent in the non-parallelogram link configuration. As the joint moves through different angles, the mechanical advantage changes automatically, providing deceleration when needed without restricting the full range of motion.
Solution Approach 2:
The mechanism changes the transmission ratio parameter continuously as the joint moves through its range of motion. The relationship between input and output angles is non-linear, with the deceleration effect being most pronounced in high-load postures where the geometry of the linkages naturally provides greater mechanical advantage.
Data Source
AI summary
A joint structure of a robot according to the present disclosure includes: a first link whose one end is connected to a first member; a second link in which one end thereof is connected to the first link and an other end thereof is connected to a second member; and a first pivot that connects an other end of the first link to the one end of the second link. The joint structure also includes: a third link whose one end is connected to the first link at a position near the first pivot; and a slide part connected to the second link so as to be slidable. An other end of the third link is connected to the slide part.