Frame-Structured Robot Arm for Low Inertia and Twist Rigidity
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Solution Overview
Problem
Existing robots face challenges in reducing the inertia force and improving rigidity, particularly in the twist directions, of their arms, which affects their ability to move quickly and efficiently.
Innovation Solution
A robot arm design featuring a frame-shaped base with ring-shaped placement portions and beams that distribute weight efficiently, enhancing strength and reducing inertia through a balanced structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the second arm is made lighter to reduce inertia force, then the rotation speed and response capability are improved, but the strength and rigidity in twist directions deteriorate
Solution Approach 1:
The second arm is divided into multiple longitudinal members (first through fourth longitudinal members) connected by lateral members, creating a segmented framework structure. This segmentation allows weight reduction while maintaining strength through the distributed framework, resolving the contradiction between lightness and rigidity.
Solution Approach 2:
The patent employs composite construction combining multiple longitudinal and lateral members to form a rigid framework. This composite structure achieves both weight reduction and enhanced twist rigidity by distributing mechanical loads across the framework, preventing torsional deformation while keeping individual members lightweight.
2Use of energy by moving object
If the second arm is made lighter to reduce inertia force, then power consumption is reduced, but the strength and rigidity in twist directions deteriorate
Solution Approach 1:
The segmented framework structure with multiple longitudinal and lateral members enables weight reduction for lower power consumption while maintaining twist rigidity through the distributed structural arrangement.
Solution Approach 2:
The composite framework of multiple members provides both weight reduction for energy efficiency and sufficient twist rigidity through the interconnected structure that resists torsional forces.
3Strength
If a traditional solid structure is used for the second arm, then strength and rigidity are improved, but weight increases leading to higher inertia force
Solution Approach 1:
Instead of a solid structure, the second arm uses a segmented framework of longitudinal and lateral members, reducing weight while maintaining rigidity through the distributed structural arrangement.
Solution Approach 2:
The framework structure acts as a lightweight alternative to solid construction, using thin-walled members arranged in a rigid configuration that provides sufficient strength without the weight of solid material.
4Speed
If the second arm is made lighter, then the inertia force is reduced for faster movement, but the structural integrity deteriorates
Solution Approach 1:
The segmented framework maintains structural integrity despite weight reduction by distributing loads across multiple members, preventing localized failure and maintaining overall stability during fast movement.
Solution Approach 2:
The composite framework structure provides both weight reduction for fast movement and structural integrity through the interconnected arrangement of members that collectively resist deformation and maintain stability.
Data Source
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AI summary
A robot includes a base, a first arm coupled rotatably around a first rotation axis relative to the base, a second arm having a base formed by a frame-shaped member and rotating around a second rotation axis parallel to the first rotation axis relative to the first arm, a shaft placed at an opposite side to the first arm of the second arm, a drive unit rotationally driving the second arm around the second rotation axis relative to the first arm, and a supporting portion supporting the shaft to rotate around a third rotation axis parallel to the second rotation axis and move the shaft along an axial direction of the third rotation axis, wherein the base has a first placement portion in which the drive unit is placed, a second placement portion in which the supporting portion is placed, a first beam placed over between the first placement portion and the second placement portion, and a second beam placed over between the first placement portion and the second placement portion and having a projecting portion projecting toward an axial direction of the second rotation axis relative to the first beam.