Robotic Arm Spherical Linkage Size Reduction
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Solution Overview
Problem
Conventional robotic arms with spherical five-bar linkages are large and restrictive, limiting their movement and obstructing medical personnel in minimally invasive surgery systems due to their size and interdependent link movements.
Innovation Solution
A robotic arm design with fewer bent links, utilizing first and second bent links, driving units, wheels, and flexible ropes to achieve a smaller size and wider range of motion, allowing for more space and improved control over surgical tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional robotic arm uses four bent links with spherical five-bar linkage, then the robotic arm achieves accurate control of swinging direction and angle, but the robotic arm becomes quite large and occupies significant space
Solution Approach 1:
The patent extracts and eliminates redundant bent links from the conventional four-link spherical five-bar linkage, reducing the structure to essential components while maintaining the spherical rotation center and control precision through a simplified mechanism
Solution Approach 2:
The robotic arm is segmented into distinct functional modules: a support structure with first and second bent links, driving units with wheels, and flexible ropes for actuation. This segmentation allows each component to be optimized independently, reducing overall size while preserving control accuracy
2Ease of operation
If driving units are placed around bent links to drive rotation, then the bent links can be driven to rotate, but the rotating angle of each bent link is restricted and the sphere of action is limited
Solution Approach 1:
Flexible ropes serve as intermediaries between the driving units and bent links, transmitting rotational motion over larger angles without the mechanical interference that would limit direct drive arrangements. The ropes allow the bent links to rotate through wider ranges while maintaining controlled motion
Solution Approach 2:
The patent transitions from a planar arrangement of driving units around bent links to a three-dimensional configuration where wheels and flexible ropes operate in multiple spatial dimensions, enabling greater rotational freedom and expanding the sphere of action
Data Source
AI summary
A robotic arm includes first and second bent links and a tool link pivotally connected in order, first to third wheels, and first to fourth imaginary axes intersecting at a center of spherical rotation. The first bent link and wheel are driven to rotate about the first and third imaginary axes respectively. A first flexible rope is wound around the first and second wheels and fixed to the second bent link for driving the second wheel and bent link to rotate about the second imaginary axis when the first wheel rotates. A second flexible rope is wound around the second and third wheels and fixed to the first bent link for driving the third wheel and the tool link to rotate about the fourth imaginary axis when the second wheel rotates. The robotic arm is relatively smaller, obstructs the operator less and produces a wider sphere of action.