Robot Joint Structure Using Elastic Member Inversion
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Solution Overview
Problem
Existing robot finger structures require a large actuator to overcome the restoring force of torsion springs, leading to increased size and cost, making them less efficient for grasping components.
Innovation Solution
A four-link mechanism with elastic members, where the elastic members' restoring force assists the actuator's driving force, allowing for a smaller actuator size and improved grasping efficiency, using ring members made of resin to reduce space and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If torsion springs are used to connect finger plates and exert restoring force in the extending direction, then the finger structure can maintain its shape and provide restoring force, but the actuator size increases because a driving force must overcome the restoring force
Solution Approach 1:
The patent inverts the conventional approach by using elastic members that exert restoring force in the bending direction rather than the extending direction. This inversion allows the restoring force to assist the actuator during finger extension, eliminating the need for the actuator to overcome the spring force, thereby reducing actuator size while maintaining grasping capability
Solution Approach 2:
The patent converts the harmful effect of the restoring force (which previously had to be overcome by the actuator) into a beneficial effect. By positioning the elastic member to exert restoring force in the bending direction, the force that would normally resist the actuator is instead made to assist the actuator, reducing the required driving force and actuator size
2Strength
If torsion springs are used to connect finger plates, then the finger structure can provide restoring force, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the torsion spring component from the finger plate connection structure and replaces it with an elastic member positioned between the first and second finger plates. This extraction simplifies the overall structure by eliminating the need for complex torsion spring mechanisms while maintaining the essential restoring force function
Solution Approach 2:
The patent replaces expensive and complex torsion springs with simpler, more cost-effective elastic members. The elastic members can be implemented using flexible materials or simple spring elements that are cheaper to manufacture and easier to replace, reducing both device complexity and manufacturing cost
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
The joint structure enables a robot hand to grasp components with a smaller driving force, reducing the size and weight of the actuator, while providing a more robust grasping mechanism.
Implementation Method 1
the first elastic member expands and its restoring force increases as the finger is bent
Data Source
AI summary
A joint structure for a robot including a four-link mechanism, in which an elastic member expands and its restoring force increases as a finger is bent, and a distance between a second straight line passing through a center of a second rotation shaft and a fixed point at which the other end of the elastic member is fixed to the third link is equal to or longer than a distance between a fourth straight line passing through a center of a first rotation shaft and a fixed point at which one end of the elastic member is fixed to the second link, the second straight line being perpendicular to a first straight line passing through centers of second and fourth rotation shafts, and the fourth straight line being perpendicular to a third straight line passing through centers of first and third rotation shafts.