Robotic Tool Changer Pressure Sensing for Safe Uncoupling

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Solution Overview

Problem

Existing robotic tool changer devices lack sufficient safety mechanisms to prevent unsafe uncoupling due to energy supply failures, such as loss or variation of pneumatic, electrical, or hydraulic power, which can lead to dangerous conditions, and there is a need for a system that ensures uncoupling only occurs in designated and controlled locations.

Innovation Solution

A tool changer device for robotic arms featuring a robot adapter with a pneumatic cylinder and differential pressure sensors to detect coupled, uncoupled, and intermediate positions, along with a safety control module and bi-stable pneumatic solenoid valves to implement AND/OR pneumatic logic, ensuring safe uncoupling only when necessary safety conditions are met.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a tool changer device uses a pneumatic cylinder with basic coupling/uncoupling mechanism, then the device complexity is low, but the safety reliability is insufficient to prevent unsafe uncoupling due to energy supply failures

Engineering Contradiction:
Improvesafety reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces differential pressure sensors as intermediary devices that detect the actual coupling state by measuring pressure differences in the pneumatic system. These sensors act as mediators between the pneumatic cylinder and the control system, providing accurate feedback about whether the tool is truly coupled or uncoupled, thereby preventing unsafe operations without requiring complete system redesign

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where differential pressure sensors continuously monitor the pneumatic pressure conditions and provide real-time information to the control system. This feedback loop enables the system to detect intermediate states, verify proper coupling, and prevent uncoupling operations when safety conditions are not met, thereby improving reliability while maintaining manageable complexity

Inventive Principle:
Principle #23Feedback

2Reliability

If the tool changer device adds redundancy mechanisms to prevent uncoupling during energy loss, then the safety reliability improves, but the device complexity increases

Engineering Contradiction:
Improvesafety reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs bi-stable pneumatic solenoid valves that automatically maintain their state (coupled or uncoupled) without requiring continuous energy input. These valves use the pneumatic pressure differential and mechanical feedback to self-maintain their position, providing inherent safety during energy supply failures without requiring complex external redundancy systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes pneumatic pressure differentials and bi-stable pneumatic valves to create an inherently safe system that relies on pneumatic principles rather than complex mechanical or electronic redundancy. The pneumatic system naturally maintains coupling state through pressure balance, and only releases when specific pressure conditions are met, providing safety through the physics of the pneumatic system itself

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Measurement precision

If the device uses basic pressure detection, then the measurement precision is low, but the device complexity remains low

Engineering Contradiction:
Improveposition detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical position detection mechanisms with differential pressure sensing. Instead of using mechanical switches, limit switches, or position sensors that would require direct mechanical contact and complex wiring, the system uses pneumatic pressure differences to indirectly and precisely determine the coupling state, achieving higher measurement precision with simpler overall system architecture

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution enhances safety by preventing unsafe uncoupling events, detecting missing or insufficient air pressure, and employing redundant safety mechanisms to guarantee that tools are released only in safe conditions, thereby reducing the risk of hazardous situations.

Implementation Method 1

a first differential pressure sensor connected to at least two of the through conduits, and a second differential pressure sensor connected to another two of the through conduits

Methodology Applied
Scientific EffectDifferential pressure sensing: Pressure Gradient

Implementation Method 2

bi-stable pneumatic solenoid valves to implement AND/OR pneumatic logic

Methodology Applied
Scientific EffectElectromagnetic actuation: Solenoid

Data Source

PatentEP3584044B1Tool changer device for a robotic arm
Publication Date: 2021.03.24 EFFECTO GRP SPA
  • EP3584044B1 patent drawingFigure 1
  • EP3584044B1 patent drawingFigure 2
  • EP3584044B1 patent drawingFigure 3

AI summary

A tool changer device for a robotic arm comprising a robot adapter (1) particularly adapted to be connected to a robotic arm (5) and to a tool (6). The robot adapter (1) comprises a pneumatic cylinder (117) inside which a piston (116) is slidably arranged for activating a coupling and uncoupling mechanism (120) of the robotic arm (5) to the tool (6). On one of the walls of the robot adapter (1) at least four through conduits (24, 25, 26, 27) are arranged, one end of which opens into the pneumatic cylinder (117) and another end of which opens outside of the pneumatic cylinder (117). The device further comprises a first differential pressure sensor (18) connected to at least two of the through conduits (24, 25), and a second differential pressure sensor (19) connected to another two of the through conduits (26, 27).