Robot Wrist Joint Wire Length Stability and Friction Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing robotic hand systems face challenges in maintaining the length of the wire transmission system when the wrist joint operates, leading to increased friction and reduced power transmission efficiency, which complicates the control of finger joints and restricts the range of motion.
Innovation Solution
The proposed solution involves a yaw-direction wrist joint with a fixed frame and a rotatably coupled yaw-direction frame, where the first actuator is coupled with the yaw-direction frame, and a guide protrusion and groove system to maintain the length of the power transmission wire, preventing changes in wire length during wrist joint operation and minimizing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If wires are inserted into a tube to maintain constant length during wrist joint operation, then wire length stability is improved, but friction between wire and tube increases significantly
Solution Approach 1:
The patent extracts the wire from the confining tube structure and allows it to move freely through the wrist joint. The wire passes directly through the wrist joint without being constrained by a tube, eliminating the friction problem while maintaining length stability through the mechanical coupling of the wrist joint mechanism itself.
Solution Approach 2:
The patent introduces pulleys as intermediary elements that the wire winds around. These pulleys are attached to the wrist joint mechanism, allowing the wire to change length in coordination with wrist joint movement. The pulleys act as mediators that convert wrist joint motion into controlled wire length changes, preventing unwanted finger joint movement while avoiding friction from tube confinement.
2Adaptability or versatility
If the range of motion of the wrist joint is increased, then robot hand flexibility is improved, but friction between wire and tube increases due to excessive bending
Solution Approach 1:
The wire is extracted from the tube that constrained its movement. Without the tube, the wire can bend and flex freely to accommodate increased wrist joint range of motion without experiencing excessive friction or resistance from the tube walls.
Solution Approach 2:
The system transitions from a static tube structure to a dynamic configuration where the wire and pulleys move together with the wrist joint. The pulleys are attached to the wrist joint mechanism, so they move dynamically with it, allowing the wire to maintain optimal geometry and minimize friction during large range of motion movements.
3Loss of energy
If two pulleys are used to reduce friction from wrist joint movement, then power transmission efficiency is improved, but the actuator moves in pitch direction causing wire length changes
Solution Approach 1:
The patent merges the pitch direction actuator with the wrist joint mechanism by attaching the actuator to the pitch-direction frame. This integration ensures that when the wrist joint moves in pitch direction, the actuator moves together with it, maintaining constant distance between the actuator and the wire attachment point, thereby preventing unwanted wire length changes.
Solution Approach 2:
The patent replaces the separate actuator system with a mechanically integrated system where the actuator is coupled to the pitch-direction frame. This mechanical substitution ensures that actuator movement is synchronized with wrist joint movement, eliminating the relative motion that caused wire length changes while maintaining the friction-reducing pulley system.
Data Source
AI summary
A robot has a structure in which finger joints do not interfere with each other. The robot includes a first actuator driving the finger joint, a first power transmission, a second actuator driving the finger joint, and a second power transmission. The first actuator and the first power transmission are coupled with a wrist joint so that the position of the first actuator and the first power transmission is changed. Accordingly, even if the wrist joint operates, the distance between the first actuator and the finger joint is constantly maintained.