Coupled Parallel Link Mechanism for Straight-Line Fingertip Motion
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Solution Overview
Problem
Robot hands using Chebyshev link mechanisms have a complex structure, leading to difficulties in achieving sufficient strength and reliability, and struggle to move the tip end part straight during gripping operations.
Innovation Solution
A link mechanism comprising a first parallel link mechanism, a second parallel link mechanism, a fixed structure, and a coupling link that connects side links between the two mechanisms, allowing the second parallel link mechanism to oscillate and draw the intermediate link closer to the base, maintaining a consistent depth and enabling a substantially linear motion of the tip end part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a Chebyshev link mechanism is used to move the fingertip substantially straight, then the gripping operation is improved without depth change, but the structure becomes complex with many parts
Solution Approach 1:
The mechanism is divided into two separate parallel link mechanisms (first and second) connected in series, where each mechanism handles a portion of the motion control. This segmentation allows the complex straight-line motion to be achieved through simpler individual mechanisms working together, reducing the overall part count compared to a single Chebyshev mechanism.
Solution Approach 2:
Two parallel link mechanisms are combined in series with a coupling link to achieve the straight-line motion function. By merging these mechanisms, the patent creates a system that accomplishes the same function as a Chebyshev mechanism but with fewer total parts and simplified individual components.
2Reliability
If a Chebyshev link mechanism is used to maintain constant depth, then the gripping operation is improved, but the structure becomes complex
Solution Approach 1:
The depth control function is segmented between two parallel link mechanisms connected in series. The first mechanism handles the primary motion while the second mechanism, coupled through a coupling link, ensures the intermediate link is drawn to the base side, maintaining constant depth. This segmentation achieves reliable depth control with simpler individual mechanisms.
Solution Approach 2:
The coupling link acts as an intermediary element that connects the first and second parallel link mechanisms. It transmits motion from the first mechanism to the second, enabling the second mechanism to oscillate and draw the intermediate link to the base side, thereby maintaining constant depth during gripping operations.
3Device complexity
If a simple rotary type finger mechanism is used, then the structure is simple, but the depth from fingertip to base changes during oscillation
Solution Approach 1:
Two simple parallel link mechanisms are merged in series to achieve constant depth motion. While each individual mechanism is simple in structure, their combination through the coupling link creates a system that maintains constant depth, resolving the contradiction between simplicity and precision.
Solution Approach 2:
The mechanism adds a second degree of freedom by connecting two parallel link mechanisms in series. This dimensional extension allows the system to control both the primary motion and the depth maintenance, achieving constant depth without requiring a complex single-mechanism solution.
Data Source
AI summary
[Problem] Provided is a link mechanism capable of moving a tip end part substantially straight by using a simpler structure. [Solution] A link mechanism including a first parallel link mechanism having a fixed link and an intermediate link parallel to each other, and a pair of side links parallel to each other, a second parallel link mechanism having a fixed link and an intermediate link parallel to each other, and a pair of side links parallel to each other, in which the fixed link is connected to the intermediate link of the first parallel link mechanism, a fixed structure that is formed including the intermediate link of the first parallel link mechanism and the fixed link of the second parallel link mechanism, and a coupling link that couples one of the side links of the first parallel link mechanism and one of the side links of the second parallel link mechanism.