Wire-Locked Robot Joint Structure for Wide-Range Compliance
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Solution Overview
Problem
Existing robot manipulators with highly rigid mechanisms face challenges in performing operations requiring contact with objects and higher accuracy than sensor measurement, while compliance mechanisms have narrow movable ranges and complex structures.
Innovation Solution
A joint structure for robots that switches between a locked and free state using a flexible wire-shaped member to connect elements, allowing large movable ranges and simple, compact design with external driving sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If compliance mechanisms are used to enable contact operations, then the robot can perform operations requiring contact with objects, but the movable range becomes very narrow and the structure becomes complex and larger
Solution Approach 1:
The actuator is extracted from the joint structure and placed outside. The wire-shaped member serves as a flexible coupling that transmits force from the external actuator to the joint, eliminating the need for internal actuator mounting while maintaining compliance functionality.
Solution Approach 2:
A wire-shaped flexible member is used instead of rigid mechanical connections. This flexible coupling allows the joint to maintain compliance and movable range while transmitting forces from the external actuator, resolving the contradiction between contact capability and structural complexity.
2Adaptability or versatility
If compliance mechanisms are used to enable contact operations, then the robot can perform operations requiring contact with objects, but the movable range becomes very narrow
Solution Approach 1:
The joint structure dynamically adjusts its compliance level by controlling the wire-shaped member's tension and length. This allows the system to transition between a compliant state for contact operations and a rigid state for positioning, enabling large movable ranges when needed.
Solution Approach 2:
The compliance mechanism changes the physical parameters of the wire-shaped member (length, tension) to adjust the joint's movable range. By varying these parameters, the system can achieve both contact operation capability and large movable range.
3Reliability
If an actuator is provided inside the joint to drive the locking mechanism, then the locking function can be achieved, but the structure becomes complex and larger
Solution Approach 1:
The actuator is completely extracted from the joint structure and positioned externally. The wire-shaped member acts as a flexible transmission element that carries the actuator's force to the joint, achieving the locking function without internal actuator complexity.
Solution Approach 2:
The wire-shaped member serves as an intermediary that transmits force from the external actuator to the joint's locking mechanism. This flexible coupling enables reliable locking while keeping the joint structure simple and compact.
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 a robot joint structure with a large movable range and stable orientation, facilitating operations like conforming to uneven surfaces, with a simple and lightweight configuration.
Implementation Method 1
a flexible wire-shaped member, one end of which is attached to the second member and another end of which is led out to the outside of the joint structure via a through hole provided in the first member, and the joint structure enters the locked state by the wire-shaped member being pulled
Implementation Method 2
an elastic member, one end of which is attached to the first member and the other end of which is attached to the second member, and a protrusion provided at the second member is fitted to a recess provided at the first member when the wire-shaped member is in a state of being pulled
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
A joint structure includes a locking mechanism for switching a free state in which a second element is independent from a first element and capable of moving, and a locked state in which the second element is fixed to the first element. The locking mechanism includes a first member joined to the first element, a second member joined to the second element, and a flexible wire-shaped member in which one end thereof is attached to the second member and another end thereof is led out to the outside of the joint structure via a through hole provided in the first member. The joint structure enters the locked state by the wire-shaped member being pulled to bring the second member into contact with the first member, and enters the free state by the wire-shaped member being fed to separate the second member from the first member.