Robot Motion Coordination for Overlapping Work Area Collision Avoidance

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Solution Overview

Problem

Existing robot systems with overlapping work areas face challenges in minimizing footprint while fully utilizing robot capacities, as current collision avoidance methods either increase footprint or restrict operations within overlapping zones, leading to underutilization of robot capabilities.

Innovation Solution

A method where robot controllers share movement information to select non-colliding robot movements, allowing simultaneous operation within overlapping work areas by determining safe paths and movements for each robot, thereby optimizing pick and place tasks without risking collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If robots are positioned closer to each other to decrease footprint, then the footprint is reduced, but the risk of collision increases due to overlapping work areas

Engineering Contradiction:
ImprovefootprintVSAvoidcollision risk
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The system dynamically adjusts robot operations by continuously monitoring movement information and determining collision risks in real-time. Instead of static separation, the robots can operate in overlapping areas when dynamic coordination ensures safe movement paths, allowing footprint reduction while maintaining safety through adaptive control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The collision avoidance mechanism uses feedback from movement information provided by one robot to the other's controller. The system retrieves this information, determines collision risks, and adjusts operations accordingly, creating a closed-loop control system that enables safe operation in overlapping work areas

Inventive Principle:
Principle #23Feedback

2Reliability

If buffer zones are defined to prevent collisions, then collision risk is reduced, but robot capacities are not fully utilized due to restricted operations

Engineering Contradiction:
Improvecollision avoidanceVSAvoidrobot capacity utilization
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

Instead of completely restricting access to overlapping areas through buffer zones, the system allows partial access by evaluating individual movement paths. Robots can enter overlapping areas when specific movement conditions are met, utilizing more of their work space and capacity while still preventing collisions through selective movement authorization

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system changes the operational parameters by using dynamic movement information and real-time risk assessment instead of static buffer zone restrictions. This allows robots to operate throughout their full work areas by adjusting operations based on current movement states rather than permanent spatial restrictions

Inventive Principle:
Principle #35Parameter changes

3Reliability

If working ranges are limited by software to be smaller than work areas, then collision risk is reduced, but the robots' work areas are not utilized in full

Engineering Contradiction:
Improvecollision preventionVSAvoideffective work area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The effective work area dynamically expands to include overlapping regions when movement coordination ensures safety. Instead of static reduced work ranges, the system allows robots to access the full geometric work area by continuously adjusting operational permissions based on real-time movement information and collision risk assessment

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3256292B1A method for avoiding collisions between two robots
Publication Date: 2022.05.11 ABB (SCHWEIZ) AG
  • EP3256292B1 patent drawingFigure 1
  • EP3256292B1 patent drawingFigure 2

AI summary

In a robot system (10) comprising a plurality of robots (20, 40) with overlapping work areas (60) a risk for collision between the robots (20, 40) exists if they are allowed to simultaneously operate within the overlapping work areas (60). A method for avoiding collisions between two robots (20, 40) in such robot system (10) comprises the steps of: providing (320) first movement information (240) related to a first robot movement (190)which is to be executed (360) by a first robot (20); retrieving (340) the first movement information (240); determining (350) for a plurality of second robot movements (210) whether they involve a risk for collision between the first and second robots (20, 40); and executing (360) one of the second robot movements (210). In a robot system (10) configured to carry out a pick and place task each robot (20, 40) oftentimes has a plurality of available robot movements that can be executed (360) depending on which item (140) to pick or at which empty place (160) to place an item (140). Information about a movement of one robot (20, 40) enables a robot controller (70, 80) of another robot (20, 40) with an overlapping work area (60) to select (330) among available robot movements an appropriate one that does not involve a risk for collision between the two robots (20, 40).