Robot Arm Sensor Failure Detection via Motor Deviation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional robot systems fail to prevent abnormal operation when the sensor for detecting acceleration and velocity fails, leading to potential safety hazards.
Innovation Solution
A robot system that includes a servo motor, a robot arm, a robot controller, a first detection section for the servo motor's rotation, a second detection section at the robot arm's tip for velocity or acceleration, a computation section to calculate deviations, and an emergency stop section that activates when deviations exceed a reference value, ensuring safe shutdown even if the acceleration sensor fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a sensor-based detection system is used to monitor robot acceleration and velocity, then the response speed to abnormal operations is improved, but the system becomes vulnerable to sensor failures that compromise safety
Solution Approach 1:
The patent introduces a computation section that acts as an intermediary by calculating expected acceleration and velocity values from motor rotation data, then comparing these computed values with sensor-measured values. This intermediary computation layer provides a backup verification mechanism that does not depend on sensor functionality, thereby maintaining safety even when sensors fail.
Solution Approach 2:
The system implements feedback by continuously comparing the acceleration and velocity detected by sensors with those computed from motor rotation amounts. When the deviation between detected and computed values exceeds a threshold, the system triggers an emergency stop. This feedback mechanism enables real-time validation of sensor data against physically expected values, detecting sensor failures and maintaining system safety.
2Device complexity
If only sensor-based detection is used, then the device complexity is reduced, but the measurement reliability deteriorates due to sensor failures
Solution Approach 1:
The patent merges two detection approaches: sensor-based direct measurement and computation-based indirect measurement derived from motor rotation data. By combining these two independent detection methods, the system achieves redundant verification where each method compensates for the other's weaknesses, particularly protecting against sensor failures while maintaining relatively simple device architecture.
Data Source
AI summary
A robot system including a robot arm driven by a servo motor; and a robot controller controlling an operation of the robot arm. The robot system further comprises a first detection section detecting a rotation amount of the servo motor; a second detection section attached to a tip portion of the robot arm, and detecting a velocity or acceleration of the tip portion of the robot arm; a computation section computing the velocity or acceleration of the tip portion of the robot arm based on values detected by the first detection section, and computing a deviation between this computed velocity or acceleration and the velocity or acceleration detected by the second detection section; and an emergency stop section for bringing the servo motor to an emergency stop when a magnitude of the deviation computed by the computation section is greater than a reference value.