Bin-Picking Robot Stirring Mechanism for Part Disentanglement

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Solution Overview

Problem

Industrial robot manipulators face challenges in bin picking due to the variability of part locations and orientations, leading to errors such as collision, failure to grasp, and manual intervention requirements, as existing solutions are costly, inflexible, and have high failure rates.

Innovation Solution

A robot with a moveable arm and computing device, equipped with a compliant end-of-arm tool that can adjust its position and orientation using air pressure or spring-based compliance, allowing for dynamic adjustment to compensate for errors and reduce damage during bin picking, and incorporating force sensing for intelligent error handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid end-of-arm tool is used for bin picking, then the robot structure is simple and cost-effective, but parts are damaged due to lack of compliance and the robot cannot adapt to misalignments

Engineering Contradiction:
ImprovecomplianceVSAvoidend-of-arm tool complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The end-of-arm tool incorporates a compliant mechanism that changes its rigidity parameter dynamically. The mechanism transitions from a rigid state during normal operation to a compliant state during error recovery, allowing the robot to adapt to misalignments and prevent part damage while maintaining structural simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The end-of-arm tool employs a dynamic compliance mechanism that can switch between rigid and flexible states. This dynamic adjustment allows the robot to handle misaligned parts gracefully by allowing controlled movement and rotation, reducing damage while maintaining overall system simplicity

Inventive Principle:
Principle #15Dynamics

2Reliability

If the robot stops for manual intervention when errors occur, then error handling is thorough, but productivity decreases due to frequent interruptions

Engineering Contradiction:
Improveerror handlingVSAvoidpicking rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The robot system incorporates automated error recovery capabilities where the compliant end-of-arm tool can independently handle misalignment errors through controlled stirring motions and rotation attempts. This self-service mechanism resolves common picking errors without requiring manual intervention, maintaining reliability while preserving productivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary error detection and automated correction attempts before requiring manual intervention. The compliant mechanism proactively handles misalignments and the controller attempts multiple recovery strategies, ensuring thorough error handling while minimizing production stoppages

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If vision system fails to recognize pickable parts, then measurement accuracy is maintained, but the robot cannot find valid grasp points leading to errors

Engineering Contradiction:
Improvepart detection accuracyVSAvoiderror recovery capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The compliant end-of-arm tool enables the robot to adapt to cases where vision detection is insufficient. By allowing physical interaction and stirring motions, the system can discover pickable parts that were not initially detected, maintaining measurement precision for clearly visible parts while adding adaptability for borderline cases

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback from the compliant mechanism during stirring and exploration motions. When vision detection fails to identify pickable parts, the physical feedback from part contacts guides the robot to discover valid grasp points, combining precise vision-based detection with adaptive tactile exploration

Inventive Principle:
Principle #23Feedback

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 compliant end-of-arm tool enhances the robot's ability to successfully pick parts by adjusting to misalignments and errors, reducing damage and increasing flexibility, while force sensing enables intelligent responses to errors, improving the reliability and efficiency of bin picking operations.

Implementation Method 1

adjust its position and orientation using air pressure or spring-based compliance

Methodology Applied
Scientific EffectAir pressure: Pressure Increase

Implementation Method 2

adjust its position and orientation using air pressure or spring-based compliance

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

incorporating force sensing for intelligent error handling

Methodology Applied
Scientific EffectForce sensing: Force

Data Source

PatentEP2346649B1Bin-picking robot with means for stirring the parts in the bin
Publication Date: 2020.07.29 ABB (SCHWEIZ) AG
  • EP2346649B1 patent drawingFigure 1
  • EP2346649B1 patent drawingFigure 2
  • EP2346649B1 patent drawingFigure 3

AI summary

A robot for picking one or more parts (41) randomly distributed in a bin (40), this robot comprising a moveable arm (16a, 16b), a computing device (14) connected to said robot for controlling motion of said moveable arm and a tool (24) connected to said moveable arm for picking one or more of said parts from said bin,- said robot using said picking tool by itself or another tool (96, 98) mounted on the robot or grasped by the picking tool to stir one or more of said one or more randomly distributed parts in said bin when said computing device determines that a predetermined event requiring stirring of said parts has occurred.