Robot Arm Joint Design with Wire-Driven Pulley Transmission
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Solution Overview
Problem
Current robot arms face challenges in achieving high strength, rigidity, precision, and working speed while ensuring safety during contact and collision, and their complex structures often compromise performance.
Innovation Solution
A robot arm design featuring a shoulder joint assembly, elbow joint assembly with a unique pulley system, and wrist joint assembly with a multi-degree-of-freedom bevel gear mechanism, which simplifies the structure while maintaining high strength and rigidity, allowing for efficient power transmission and precise motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a complex joint structure is used to ensure multi-degree of freedom and sufficient strength and rigidity, then strength and rigidity are improved, but device complexity increases and weight increases
Solution Approach 1:
The joint structure is divided into modular components: a drive unit module containing the actuator, a transmission module with pulleys and wires, and joint modules with curved surfaces. This segmentation allows each component to be optimized independently while maintaining overall strength and rigidity through standardized connections.
Solution Approach 2:
The patent implements a nested arrangement where the drive unit is positioned within the upper arm portion, the transmission module connects the drive unit to joint modules, and multiple pulleys are arranged concentrically. This nesting reduces the overall footprint and structural complexity while maintaining mechanical strength.
2Strength
If a complex joint structure is used to ensure multi-degree of freedom and sufficient strength and rigidity, then strength and rigidity are improved, but the robot arm becomes heavier
Solution Approach 1:
The patent replaces traditional heavy mechanical gear transmissions with a wire-based transmission system using pulleys and tensioned wires. This substitution significantly reduces the weight of moving components while maintaining the required torque transmission capability through the curved surface contact mechanism.
Solution Approach 2:
The patent uses thin wire elements instead of bulky mechanical linkages to transmit force between joints. The wire-based transmission system with pulleys provides sufficient strength while minimizing the weight of the robot arm segments.
3Device complexity
If the structure is simplified to reduce complexity and weight, then device complexity is reduced and weight is reduced, but strength and rigidity deteriorate
Solution Approach 1:
The patent employs curved surfaces on the joint modules that contact the transmission module's pulleys. This curvature design concentrates contact forces along defined paths, providing high local pressure and friction for effective force transmission without requiring complex mechanical linkages, thus maintaining strength while simplifying the overall structure.
Solution Approach 2:
The joint structure combines materials with different properties: the drive unit and structural components use high-strength materials for rigidity, while the transmission wires use high-tensile-strength materials. This composite approach allows structural simplification while maintaining overall strength through material optimization.
4Strength
If high strength and rigidity are achieved through complex structures, then strength and rigidity are improved, but manufacturing cost increases and maintenance becomes difficult
Solution Approach 1:
The robot arm is divided into standardized modules (drive unit, transmission module, joint modules) that can be manufactured independently using similar processes. This modular segmentation simplifies manufacturing by allowing specialization and standardization of production techniques for each module type, reducing overall manufacturing complexity and cost.
Solution Approach 2:
The patent designs universal joint modules that can be used across multiple joints with the same degree of freedom. The standardized curved surface geometry and interface designs allow the same components to serve multiple functions in different locations, reducing the total number of unique parts and simplifying manufacturing and maintenance.
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 design achieves high strength, rigidity, and precision with a simple structure, enabling the robot arm to perform tasks quickly and efficiently while reducing manufacturing costs and facilitating maintenance.
Implementation Method 1
a second curved surface portion which has an arc shape and contacts the first curved surface portion, and rotates along the first curved surface portion
Data Source
AI summary
A robot arm according to the present invention includes: a shoulder joint assembly which is connected to an upper arm portion, and includes a drive unit for generating driving power; an elbow joint assembly which is provided between the upper arm portion and a forearm portion, and operates by being supplied with driving power from the drive unit; and a wrist joint assembly which is provided between the forearm portion and a hand portion, and operates by being supplied with driving power from the drive unit.