Parallel Link Mechanism Geometry to Avoid Singular Points
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Solution Overview
Problem
Existing parallel link mechanisms face challenges in achieving a wide operating range without increasing size and reducing rigidity, and the existence of singular points limits movement flexibility and control.
Innovation Solution
A parallel link mechanism with a two-degrees-of-freedom design that avoids singular points by setting specific axis angles and includes posture control actuators, allowing for a wide range of motion and smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the link length is increased to achieve a large operating range, then the operating range is improved, but the dimensions and size of the entire mechanism are increased
Solution Approach 1:
The invention changes the geometric parameters of the link mechanism, specifically setting the axis angle γ to 60° and optimizing link length ratios. This allows achieving a wide operating range (maximum bending angle θmax ≥ 90°) without proportionally increasing the overall mechanism dimensions, as the optimized parameter configuration enables more efficient space utilization
2Adaptability or versatility
If the link length is increased to achieve a large operating range, then the operating range is improved, but the rigidity of the entire mechanism is reduced
Solution Approach 1:
The invention optimizes the parameter configuration by setting the axis angle γ to 60° and establishing specific link length ratios. This parameter optimization enables the mechanism to achieve a wide operating range while maintaining adequate rigidity, as the optimized configuration distributes mechanical loads more effectively throughout the structure
3Productivity
If the operating speed is increased to achieve high speed operation, then the productivity is improved, but the precision of operation may be reduced due to vibration and dynamic effects
Solution Approach 1:
The invention incorporates dynamic optimization by carefully selecting link lengths and axis angles that minimize vibration and dynamic imbalances during high-speed operation. The optimized parameter configuration (γ = 60°, specific link length ratios) reduces inertial forces and vibrational effects, enabling high-speed operation while maintaining operational precision
4Adaptability or versatility
If the mechanism operates near singular points to achieve maximum range of motion, then the adaptability is improved, but the control stability and precision are reduced
Solution Approach 1:
The invention takes preliminary action by pre-defining the axis angle γ as 60° and optimizing link length ratios before operation begins. This pre-optimization ensures that the mechanism operates in a configuration that maximizes the range of motion while avoiding singular points, thereby maintaining control stability and precision throughout the operating range
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In a parallel link mechanism (9), a distal end side link hub (13) is coupled to a proximal end side link hub (12) via three link mechanisms (14) such that a posture of the distal end side link hub (13) can be changed. Each link mechanism (14) includes a proximal side end link member (15), a distal side end link member (16), and a center link member (17), and forms a quadric chain link mechanism (14) composed of four revolute pairs. A singular point occurs when a central axis (QA, QB) of the proximal or distal end side link hub (12, 13) and a central axis (02, 03) which is a rotation axis of a revolute pair section of the proximal or distal side end link member (15, 16) and the center link member (17) coincide with each other. An axis angle (γ) of the center link member (17) is specified such that a posture in which the singular point occurs is avoided.