Robot Forearm Cable Routing with Grounded Shielding

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Solution Overview

Problem

Conventional cable laying structures for industrial robots with visual or force sensors often result in cable interference with peripheral devices due to the external management of camera and force-sensor cables, which can be damaged by the robot's motion and prone to noise interference.

Innovation Solution

The cables for cameras or force sensors are arranged inside the robot's body and upper arm, led into the forearm, and the forearm is grounded to the same electric potential as the base, allowing the removal of the shield and sheath to enhance flexibility and prevent noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If cables are hung outside the forearm by a hanger, then the cables are easily accessible and installed, but the cables interfere with peripheral devices and are prone to damage from robot motion

Engineering Contradiction:

Improvecable installation accessibilityVSAvoidcable protection from damage and interference

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The cables are nested inside the forearm structure rather than hanging externally. The cable conduit is integrated into the forearm, allowing cables to pass through the internal space of the robotic arm, thereby eliminating external interference while maintaining organized cable management

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

A cable conduit acts as an intermediary structure that guides and protects cables from the base through the upper arm to the forearm. This intermediary channel isolates cables from external environmental factors and moving parts, preventing damage and interference

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If shield and sheath are removed from cables in the forearm, then the cables gain flexibility for robot motion, but the cables become susceptible to noise interference

Engineering Contradiction:

Improvecable flexibility for deformationVSAvoidnoise interference to signal

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The mechanical shield and sheath are replaced by an electrical grounding system. Instead of using physical protective layers, the forearm structure itself is grounded to create an equipotential environment that protects cables from noise interference while allowing mechanical flexibility

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The forearm is grounded to establish the same electric potential throughout the structure. This equipotential grounding prevents noise interference by eliminating potential differences that could induce electromagnetic interference, while allowing the cables to remain flexible without protective sheathing

Inventive Principle:

Principle #12Equipotentiality

3Object-affected harmful factors

If shield and sheath are kept on cables throughout the forearm, then noise protection is maintained, but the cables impede forearm motion and are damaged by bending and twisting

Engineering Contradiction:

Improvenoise shieldingVSAvoidforearm motion freedom

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The cable protection strategy is segmented into different zones: the cable conduit provides structural guidance from the base, while the forearm section uses electrical grounding instead of physical sheathing. This segmentation allows flexibility where needed while maintaining noise protection through the grounded forearm structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The grounded forearm structure serves as an intermediary protective environment for the cables. Instead of relying on cable sheathing, the forearm itself acts as a shielded chamber that protects signals from noise while allowing cable flexibility for full range of motion

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This solution prevents cable damage and interference with peripheral devices by allowing the forearm to act as a shield, maintaining signal integrity and flexibility during robot motion.

Implementation Method 1

The forearm is grounded to have the same electric potential as a base member of the robot to thereby electrically shielding the cables

Methodology Applied

Scientific EffectElectrical grounding: Earthing

Implementation Method 2

the forearm is grounded to have the same electric potential as a base member of the robot to thereby electrically shielding the cables

Methodology Applied

Scientific EffectElectrical shielding: Faraday Cage

Data Source

PatentUS7703349B2Cable laying structure for robot

Publication Date: 2010.04.27 FANUC LTD

AI summary

A cable laying structure for a robot, which does not interfere with external devices in a periphery of a forearm. Camera and hand control cables and motor control cables are drawn into a robot mechanism through a connection panel of a base of a robot main body. While allowing the motor control cables to sequentially diverge, the control cables are arranged in a robot arm along an upper arm portion and guided to the forearm. The control cables are introduced into the forearm with a shield and a sheath removed. After reaching an end effector-mounting face, the control cables are connected to a camera and a hand. The forearm is formed of conductive material and grounded on the base of the robot main body to have the same electric potential as the base by using an earth cable, and therefore the forearm is utilized in replacement of the shield.