Chebychev Link Robot Hand for Thin Object Gripping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional robot hands face challenges in reducing size while maintaining the ability to hold thin works without hitting supporting surfaces, as changes in fingertip interval affect height and posture, leading to difficulties in gripping thin objects.
Innovation Solution
The implementation of a Chebychev link mechanism in the robot hand, where a driving link, driven link, and intermediate link work together to allow fingertip portions to move in a straight trajectory, maintaining constant height and posture regardless of interval, enabling smaller robot hand designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a parallel link type finger mechanism is used to reduce the size of the robot hand, then the base size can be smaller than the maximum mutual interval between fingertip portions, but the heights of the fingertip portions change when the mutual interval changes, causing the fingertip portions to hit the supporting surface when holding thin works
Solution Approach 1:
The patent applies parameter changes by transitioning from a parallel link mechanism to a Chebychev link mechanism, which fundamentally alters the motion parameters of the fingertip portions. The Chebychev link mechanism is specifically designed to produce a straight-line motion trajectory for the fingertip, maintaining constant height while allowing the mutual interval to change. This parameter change in the motion trajectory resolves the contradiction by enabling small robot hand size while preventing fingertip collision with supporting surfaces during gripping operations.
2Object-affected harmful factors
If the fingertip portions are separated from the supporting surface to avoid hitting, then collision is avoided, but the fingertip portions may fail to hold the work
Solution Approach 1:
The patent changes the motion parameter of the fingertip portions from a curved trajectory (in parallel link mechanisms) to a straight-line trajectory (in Chebychev link mechanism). This parameter change allows the fingertip portions to maintain a constant distance from the supporting surface while closing the mutual interval to grip the work. The straight-line motion ensures that the fingertip portions remain parallel to the supporting surface throughout the gripping motion, preventing both collision and loss of gripping capability.
3Volume of moving object
If a simple rotary type finger mechanism is used, then the base size can be reduced, but the heights and postures of the fingertip portions change when the mutual interval changes, causing the same gripping problem
Solution Approach 1:
The patent fundamentally changes the motion parameter of the fingertip portions by using a Chebychev link mechanism instead of a simple rotary mechanism. The Chebychev link is specifically designed to produce a straight-line motion trajectory, which maintains both the height and posture of the fingertip portions constant while allowing the mutual interval to change. This parameter change in the motion trajectory resolves the contradiction by enabling compact robot hand design while maintaining stable fingertip posture throughout the gripping operation.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A robot hand 1 is configured such that a plurality of finger mechanisms 3 and 4 are disposed on a base 2 and operate so as to cause fingertip portions 19 and 20 thereof to get close to each other and separate from each other. At least one of the plurality of finger mechanisms 3 and 4 is constituted by a Chebychev link mechanism including a driving link 21 configured to be rotated about a base end portion thereof supported by the base 2, a driven link 22 having a base end portion coupled to the base 2 so as to be swingable, and an intermediate link 23 having a base end portion coupled to a tip end portion of the driving link 21 so as to be swingable and a center portion coupled to a tip end portion of the driven link 22 so as to be swingable. The fingertip portions 19 and 20 are respectively provided at tip end portions of the intermediate links 23.