Robot Arm Offset Joint Design for Compact Reach
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Solution Overview
Problem
Conventional robots with offset rotation axes struggle to achieve a balance between a wide moving range and compact size, as the offset design often results in arm protrusion, limiting space-saving performance and increasing interference risks.
Innovation Solution
A robot system with a seven-axis vertical articulated design, featuring offset rotation axes and a cable system that minimizes projection area by strategically aligning and offsetting rotation axes, using electric motors with holes for cable passage to reduce interference and enhance flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the rotation axis of the arm is offset to widen the moving range, then the moving range is improved, but the arm protrudes and space-saving performance deteriorates
Solution Approach 1:
The patent applies offsetting the rotation axis of the fourth joint in the vertical direction (perpendicular to the mounting surface) rather than in the horizontal direction. This dimensional change allows the arm to achieve a wide moving range while minimizing the horizontal projection area, as the offset component no longer contributes to horizontal protrusion.
Solution Approach 2:
The patent introduces asymmetric offsetting where only the fourth joint's rotation axis is offset from the axis passing through the third and fifth joints. This selective asymmetric configuration enables the arm to achieve both wide moving range and compact projection area, unlike symmetric offset configurations that cause protrusion in all directions.
2Area of stationary object
If the arm is made straight to minimize projection area, then space-saving performance is improved, but the moving range is limited
Solution Approach 1:
By offsetting the fourth joint's rotation axis in the vertical dimension rather than horizontally, the arm can maintain a straight configuration horizontally (minimizing projection area) while still achieving wide moving range through the vertical offset component during operation.
3Adaptability or versatility
If the arm is extended to widen moving range, then moving range is improved, but the robot size increases
Solution Approach 1:
The vertical offset of the fourth joint's rotation axis creates an additional degree of freedom that expands the moving range without requiring increased arm length. The offset allows the hand to reach positions that would otherwise require a longer arm, thereby achieving extended reach within a compact arm structure.
Data Source
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AI summary
A robot (1) includes a base (1, 301) and an arm formed by a plurality of members connected by a plurality of joints. The arm has an offset portion where a rotation axis of a certain joint is offset from a rotation axis of the next joint in a predetermined direction and the rotation axis of the next joint is offset from a rotation axis of a joint next to the next joint in a direction opposite the predetermined direction.