Robot Arm Joint With Segmented Plate Groove And Projection
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Solution Overview
Problem
Conventional surgical instruments with intermediate joints face complexity in control due to intricate bending mechanisms and issues with wire relaxation and tension, and have a relatively large bending radius and variable center axis length, which complicates their operation.
Innovation Solution
A joint design featuring plate-shaped segments with a groove and projection system, where the curvature of the projection is larger than the groove, allowing for relative rotation and maintaining contact points, thereby reducing wire relaxation and tension, and enabling a smaller bending radius and constant center axis length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the intermediate joints are formed with stacked circular plate-shaped segments, then the joints can be bent vertically and horizontally by desired angles, but the control of the joints becomes complex and wires experience relaxation and tension
Solution Approach 1:
The joint is divided into multiple plate-shaped segments stacked in the plate thickness direction, with each segment capable of relative rotation. This segmentation enables complex bending motions while maintaining simpler individual segment structures, reducing overall control complexity.
Solution Approach 2:
The plate-shaped segments are stacked and coupled in series, with each segment nested within the overall joint structure. This nested arrangement allows multiple segments to work together to achieve vertical and horizontal bending while maintaining a compact configuration.
2Adaptability or versatility
If the tip end of the knuckle is fitted in the clevis of the adjacent joint, then the joints can be separated for securing operating ranges, but the thickness of each joint becomes relatively large and the bending radius increases
Solution Approach 1:
The joint structure transitions from a traditional knuckle-clevis configuration to stacked plate segments arranged in the plate thickness direction. This dimensional change allows for reduced joint thickness and smaller bending radius while maintaining operating range through the series coupling of segments.
3Adaptability or versatility
If the joints are formed with larger thickness to secure operating ranges, then the joints can be separated for operation, but the bending radius becomes larger than pin joint and wire relaxation and tension increase
Solution Approach 1:
The joint is segmented into multiple thin plate-shaped segments stacked in the plate thickness direction, replacing traditional thick knuckle-clevis structures. This segmentation reduces individual segment thickness while maintaining overall operating range through the series arrangement of multiple segments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design simplifies the control of bending and stretching, reduces wire relaxation and tension, and allows for a more compact and efficient arrangement of segments, effectively addressing the complexity and inefficiency of conventional joint mechanisms.
Implementation Method 1
a projection having a partially circular cross section and extending in the second direction is provided at a second surface of the first-direction middle portion of the second segment... the projection is fitted in the groove, and a bottom portion of the groove and a top portion of the projection contact each other
Data Source
Figure 1
Figure 2
Figure 3A~4
AI summary
A joint 25 coupling links 22 of a robot arm 2 to each other includes: a plurality of plate-shaped segments 4 lined up in a plate thickness direction Z; and operating wires 71a and 71b extending through the plurality of segments 4 in the plate thickness direction Z. A groove 43 extending in a second direction X and having a partially circular cross section is provided at a first-direction-Y middle portion of a main surface 41 out of two main surfaces 41 and 42 of the adjacent segments 4, the two main surfaces 41 and 42 facing each other in the plate thickness direction Z. A projection 48 extending in the second direction X and having a partially circular cross section is provided at a first-direction-Y middle portion of the main surface 42. A curvature of the projection 48 is larger than a curvature of the groove 43. The projection 48 is fitted in the groove 43, and a bottom portion 43a of the groove 43 and a top portion 48a of the projection 48 contact each other. A dimension of the projection 48 in the plate thickness direction Z is larger than a dimension of the groove 43 in the plate thickness direction Z and smaller than a length of a line L connecting the bottom portion 43a of the groove 43 and an edge portion 43b of the groove 43.