Parallel Link Mechanism With Variable-Radius Spherical Motion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing parallel link mechanisms struggle to maintain a consistent center of rotation for the distal end member, limiting its movement to a sphere with a fixed radius and making independent control of the radius of rotation during rotational movement impossible, which complicates operation and control.
Innovation Solution
A parallel link mechanism with a five-bar chain structure, featuring first to fifth revolute pair units, allows the distal end member to move on a sphere with a variable radius by intersecting center axes at a spherical link center point, enabling three degrees of freedom, including two degrees of rotation and one degree of movement along a specific axis, thus allowing independent control of the radius of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the parallel link mechanism uses a four-bar chain structure with three or more sets of link mechanisms, then the operating range and speed are improved, but the center of rotation cannot be fixed and the radius of rotation cannot be controlled independently
Solution Approach 1:
The mechanism segments the motion control into two independent parts: the spherical intersection point controls the radius of rotation, while the distal end member controls the rotational movement. This segmentation allows independent control of radius and rotation, resolving the contradiction between wide operating range and controllable radius.
Solution Approach 2:
The spherical link center point acts as an intermediary element that mediates between the link mechanisms and the distal end member. By having the center axes of the first and second revolute pair units intersect at this fixed spherical point, the mechanism achieves both wide operating range and fixed center of rotation with controllable radius.
2Adaptability or versatility
If the link length is increased to achieve a large operating range of the traveling plate, then the operating range is improved, but the size of the entire mechanism increases
Solution Approach 1:
The mechanism uses spherical geometry by having the center axes intersect at a spherical link center point. This spherical configuration allows the distal end member to move on a sphere surface, achieving wide operating range in three-dimensional space without requiring proportionally long link lengths, thus maintaining compact size while maximizing operating range.
Solution Approach 2:
The mechanism transitions from planar motion to spherical motion by introducing the spherical link center point as the intersection of center axes. This dimensional change from 2D to 3D spherical coordinates allows the distal end member to achieve wide operating range through angular movements on a sphere rather than requiring long linear link extensions.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A parallel link mechanism (10) includes a proximal end member (1) and three or more link mechanisms (11). Three or more link mechanisms (11) connect the proximal end member (1) to a distal end member (8). In three or more link mechanisms (11), a first center axis (15a, 15b, 15c) of a first revolute pair unit and a second center axis (16a, 16b, 16c) of a second revolute pair unit intersect at a spherical link center point (30). Fifth center axes of respective fifth revolute pair units of three or more link mechanisms (11) overlap each other and intersect with the spherical link center point (30).