Bidirectional Tendon Terminator for Robotic Finger Actuation
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Solution Overview
Problem
Existing dexterous robotic systems face challenges in designing a compact and strong tendon attachment mechanism that can efficiently actuate finger joints within a small space, requiring a suitable attachment device that is both robust and space-efficient.
Innovation Solution
A bidirectional tendon terminator featuring a cylindrical member with an internal channel and a ball mechanism, where the tendon extends through a narrowed and widened portion, allowing for bidirectional pulling forces to open or close the finger, utilizing two coupled cylindrical pieces for enhanced strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a tendon attachment device is made compact to fit in a small finger space, then the device size is reduced, but the strength and load-bearing capacity may be compromised
Solution Approach 1:
The tendon terminator is divided into two separate cylindrical pieces that are coupled together, creating an internal channel structure. This segmentation allows the device to maintain a compact external dimensions while providing internal structural features (the channel and ball mechanism) that enable strong tendon attachment without increasing the overall size.
Solution Approach 2:
The ball is positioned within the tendon strands and nested within the internal channel of the cylindrical pieces. This nested arrangement allows multiple functional elements (tendon, ball, channel) to occupy the same compact space, achieving both small size and strong attachment capability through efficient spatial utilization.
2Strength
If a tendon attachment device is made strong to withstand significant forces, then the load-bearing capacity is improved, but the device complexity and size increase
Solution Approach 1:
The ball mechanism automatically engages with the internal channel structure when the tendon is pulled in either direction. The tendon's own pulling force causes the ball to wedge against the channel walls, creating a self-locking mechanism that provides strong bidirectional attachment without requiring additional complex locking components or actuation systems.
Solution Approach 2:
The internal channel includes a widened portion that changes the geometric parameters of the passage. This parameter change allows the ball to be positioned and wedged effectively within the channel, enabling strong force transmission while maintaining a compact overall device structure.
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
Enables effective actuation of robotic fingers with a compact and strong tendon termination system, capable of withstanding significant forces, such as 100 lbs, while maintaining a small footprint, thereby enhancing the dexterity and grasping capabilities of robotic hands.
Implementation Method 1
pulling on the tendon in one direction or the other direction causes a pulling force on the tendon terminator as a result of the ball being wedged within the channel
Data Source
AI summary
A bidirectional tendon terminator that has particular application for terminating a tendon that actuates a finger in a robotic arm. The tendon terminator includes a cylindrical member having an internal channel through which a single continuous piece of the tendon extends. The internal channel of the tendon terminator includes a widened portion. A ball is placed in the tendon strands, which causes the tendon to expand, and the ball is positioned within the widened portion of the channel. Pulling on the tendon operates to either open or close the finger of the robotic arm depending on which direction the tendon is pulled. In one specific embodiment, the cylinder includes two cylindrical pieces that are coupled together so that the ball can be positioned within the channel and the cylindrical member has an entire circumference of material.