Robot Safety Zone Control Based on Actuator Load

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Solution Overview

Problem

Existing robot systems face safety challenges when humans and robots share the same workspace, as the operation load of the robot's working arm varies, affecting the risk of interference and efficiency, with current safety measures being either insufficient or overly restrictive.

Innovation Solution

A robot system that includes an operation load detection unit, a region setting unit, and an abnormality determination unit, which dynamically adjusts the safety region based on the operation load of the actuator, using sensors to detect the load components and position of moving bodies, and controls the robot's motion to ensure safety and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed safety fence is disposed around the working arm to separate operation regions, then safety is improved, but working efficiency deteriorates due to excessive safety measures

Engineering Contradiction:
ImprovesafetyVSAvoidworking efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the safety region dynamically adjustable based on real-time operation load detection. The control device modifies the safety region boundaries according to the detected operation load, transitioning from a fixed safety fence to a dynamic safety zone that adapts to current robot working conditions, thereby resolving the contradiction between safety and working efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of safety region size based on operation load parameters. By detecting operation load and corresponding the load level to appropriate safety region sizes, the system adjusts safety measures proportionally to actual risk, avoiding excessive safety restrictions while maintaining adequate protection

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a fixed operation region is set for people, then safety management is simplified, but it becomes insufficient when robot operation load varies

Engineering Contradiction:
Improvesafety management complexityVSAvoidsafety sufficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements feedback by continuously detecting operation load and using this information to adjust safety region boundaries. The control device receives operation load detection results and automatically modifies safety region parameters, creating a closed-loop system that maintains adequate safety without requiring complex manual intervention

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-service by automatically adjusting safety regions based on its own operation load detection. The robot system monitors its own working conditions and autonomously modifies safety parameters without external intervention, simplifying safety management while maintaining adequacy

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2783800B1Robot system and method for controlling robot system
Publication Date: 2023.05.17 YASKAWA DENKI KK
  • EP2783800B1 patent drawingFigure 1
  • EP2783800B1 patent drawingFigure 2
  • EP2783800B1 patent drawingFigure 3

AI summary

A robot system (2) of the present disclosure includes: a robot (3) including an operable working arm (4) driven by an actuator (11); an operation load detection unit (5) configured to detect an operation load of the actuator; a region setting unit (6) that sets a region (10) with a predetermined range around the robot; a moving body detection unit (7) configured to detect a position of a moving body (9) other than the robot; and an abnormality determination unit (8) that determines abnormality when detecting of the position of the moving body within the region, wherein the region setting unit changes the range of the region in accordance with the operation load of the actuator.