Robot Workcell Safety Monitoring With Redundant COTS Sensors
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Solution Overview
Problem
Current robot safety systems face challenges in achieving safety certification using cost-effective sensors while minimizing unnecessary stoppages or slowdowns, and in tracking humans in dynamic environments with uncertainty about sensor data reliability.
Innovation Solution
A processor-based workcell safety system employing multiple heterogeneous COTS sensors with dual or triple modular redundancy, failure mode effects analysis, and diverse sensor modalities to ensure safety certification and reduce occlusions, using techniques like watchdog mechanisms and fiducial-based validation to maintain reliable sensor data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple safety certified sensors are employed to reduce occlusions, then safety monitoring reliability is improved, but system cost increases significantly
Solution Approach 1:
The patent replaces expensive safety certified sensors with multiple commercial off-the-shelf (COTS) sensors that are significantly cheaper. While individual COTS sensors may be less reliable, the system uses redundancy (multiple sensors) to achieve the required safety level, effectively substituting expensive long-lived components with cheaper shorter-lived alternatives that collectively provide equivalent or superior reliability.
Solution Approach 2:
The system changes the parameter of sensor quantity from single或少量 to multiple, and changes the sensor type parameter from safety certified to COTS. This parameter transformation allows the system to achieve safety certification through statistical reliability of multiple independent sensors rather than relying on individually certified expensive sensors.
2Reliability
If safety system triggers stoppages or slowdowns upon detecting safety conditions, then safety is improved, but robot productivity deteriorates
Solution Approach 1:
The system continuously monitors sensor data and provides feedback to the robot control system. When safety conditions are detected, feedback triggers appropriate responses (stoppage, slowdown, or alert). The feedback mechanism allows the system to distinguish between actual safety threats and false positives, reducing unnecessary stoppages while maintaining safety when truly needed.
Solution Approach 2:
Instead of triggering full stoppages for all detected safety conditions, the system applies partial actions appropriate to the severity and type of detected condition. For minor or uncertain threats, the system may issue alerts or slow down rather than complete stoppage, preserving productivity while maintaining adequate safety. This graded response reduces unnecessary productivity loss.
3Device complexity
If COTS sensors are used instead of safety certified sensors, then cost is reduced, but measurement reliability deteriorates
Solution Approach 1:
The system segments the sensing function across multiple independent COTS sensors rather than relying on a single expensive safety certified sensor. Each sensor provides partial measurement data, and the system integrates these segmented measurements to achieve comprehensive and reliable environmental monitoring, compensating for individual sensor limitations through collective redundancy.
Solution Approach 2:
The system creates a composite sensing architecture by combining multiple different types of COTS sensors (cameras, depth sensors, LIDAR, etc.) to form a unified safety monitoring system. This composite approach leverages the strengths of different sensor modalities and achieves measurement reliability through diversity and redundancy, replacing individual high-reliability sensors with a ensemble of lower-cost components.
Data Source
AI summary
A safety system for use in robotics includes a plurality sensors, preferably a heterogeneous set of commercial off the shelf sensors, and at least one processor that assesses an operational state of the sensors, validates a system status based on the assessed operational states of the sensors to determine whether sufficient sensors are operable to provide a safety certified system, and monitors an operational environment for violations of safety rules that specify rules regarding proximity of humans to robots. A control system for use in robotics includes at least one processor that performs motion planning taking into account safety monitor rules implemented by the safety system to thereby reduce triggering of stoppages, slowdowns or precautionary occlusions by the safety system.