Robot Hand Torque Multiplication via Segmented Pulley and Lever Mechanism
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Solution Overview
Problem
Conventional robot hands face challenges in generating sufficient torque to lift heavy objects while accommodating sensors for object detection, as increasing pulley diameter obstructs sensor placement.
Innovation Solution
The design incorporates a first and second fixed pulley, a lever link, and a conversion mechanism that allows for greater torque output without increasing pulley diameter, enabling a movable pulley configuration that enhances torque application to the second link, along with a base part and additional links for increased flexibility and sensor compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the diameter of the pulley is increased to generate sufficient torque for lifting heavy objects, then the torque output is improved, but the space for sensor placement is reduced due to obstruction by the pulley
Solution Approach 1:
The pulley system is segmented into multiple smaller pulleys (first fixed pulley, second fixed pulley, movable pulley) arranged in a specific configuration. This segmentation allows the cable to wrap around multiple pulleys, multiplying the torque output without requiring a single large pulley that would obstruct sensor placement on the palm.
Solution Approach 2:
The pulleys are arranged in a nested or compact configuration where the movable pulley is positioned between the first and second fixed pulleys. This nested arrangement maximizes the mechanical advantage while minimizing the overall space occupied, leaving room for sensors on the palm surface.
2Device complexity
If a fixed pulley configuration is used, then the structure is simple, but the torque multiplication capability is limited
Solution Approach 1:
The system transitions from a static fixed pulley configuration to a dynamic system that includes a movable pulley. The movable pulley moves with the cable tension, providing dynamic torque multiplication. This adds only one movable component while significantly enhancing the force output capability.
Solution Approach 2:
The movable pulley acts as an intermediary element between the cable and the link it drives. By introducing this intermediate pulley, the system achieves torque multiplication without directly increasing the size of the fixed pulleys or complicating the overall structure excessively.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for increased torque output and flexibility in robot hand operations, enabling the gripping and lifting of heavy objects while allowing for the integration of sensors, thus improving the robot hand's ability to perform tasks similar to a human hand.
Implementation Method 1
a first fixed pulley and a second fixed pulley, respectively provided at a proximal end pivot part of the first link and rotatable around a first axis with respect to the first link; a lever pulley, supported by a free end of the lever link to be rotatable; a hanging cable, hung on the first fixed pulley, the lever pulley, and the second fixed pulley
Implementation Method 2
a lever link, having a proximal end supported by the proximal end pivot part of the first link to be rotatable around the first axis; a conversion mechanism, connecting the lever link and the second link, and converting rotation of the lever link around the first axis into rotation of the second link around the second axis
Data Source
AI summary
A robot hand includes: a first link; a first fixed pulley and a second fixed pulley, respectively provided at a proximal end pivot part of the first link and rotatable around a first axis; a second link, supported at an intermediate pivot part by the first link to be rotatable around a second axis; a lever link, supported by the proximal end pivot part of the first link to be rotatable around the first axis; a lever pulley, supported by the lever link; a hanging cable, hung on the first fixed pulley, the lever pulley, and the second fixed pulley; a conversion mechanism, connecting the lever link and the second link, and converting rotation of the lever link into rotation of the second link; and a second link driving mechanism, rotating the lever link around the first axis by pulling the hanging cable.