Dual-Speed Robot Safety Control for Human-Robot Collaboration
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Solution Overview
Problem
Conventional robot safety systems that rely on external sensors to detect humans in the workspace often result in inefficient operation due to the need for wide safety zones and all-or-nothing shutdowns, which compromise both safety and efficiency.
Innovation Solution
Implementing a dual-speed safety system that distinguishes between collisions involving the torso/head and arms/hands, allowing the robot to operate at full speed when safe, with lower speed limits for torso/head collisions and higher speed limits for arm/hand collisions, using sensor systems like cameras and sonar to detect and differentiate body parts within a defined danger zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sensor systems are used to detect persons in the robot workspace, then safety is improved, but robot operation speed decreases significantly due to all-or-nothing shutdowns
Solution Approach 1:
The patent segments the detection zone into multiple regions with different safety risk levels. Instead of treating the entire workspace as a single danger zone, the system divides it into high-risk areas (where torso/head collisions are likely) and low-risk areas (where only arm/hand collisions are possible). This allows the robot to maintain full speed in low-risk zones while slowing down only when high-risk body parts are detected, resolving the contradiction between safety and productivity.
2Reliability
If a wide danger zone is defined around the robot to avoid safety risks, then safety is improved, but efficiency decreases due to unnecessary speed reductions
Solution Approach 1:
The patent applies local quality by assigning different safety requirements to different spatial locations within the detection zone. Rather than uniformly applying a single safety rule across the entire workspace, the system implements location-specific speed limits based on the local risk assessment. High-risk zones trigger lower speed limits, while low-risk zones allow full operational speed, thus maintaining safety without unnecessary efficiency losses.
3Measurement precision
If complex trajectory prediction and injury modeling are implemented to assess collision risks, then safety decision accuracy is improved, but system complexity increases
Solution Approach 1:
The patent employs relatively simple, robust sensor systems (cameras and sonar) rather than complex sensing and modeling infrastructure. The approach uses straightforward detection of body part presence in segmented zones rather than sophisticated trajectory prediction and injury vulnerability modeling. This keeps the system simple and reliable while achieving adequate safety decision accuracy through practical, implementable detection methods.
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
Enables safe and efficient robot operation near humans by allowing full-speed operation when safe, reducing unnecessary interruptions, and ensuring safety through discrete speed control and sensor-based detection, while minimizing injury risks.
Implementation Method 1
using sensor systems like cameras and sonar to detect and differentiate body parts
Implementation Method 2
using sensor systems like cameras and sonar to detect and differentiate body parts
Data Source
AI summary
In various embodiments, safe collaboration between a robot and humans is achieved by operating the robot continuously at or below a first threshold speed at which any collisions with a person's arms do not cause harm, and, upon detection of the person's torso or head within a danger zone around the robot, reducing the speed to or below a second threshold at which any collisions with the person's torso or head do not cause harm.