AGV Sensor Fault Detection Using Redundant Wheel Pair Motion Checks
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Solution Overview
Problem
Current methods for detecting sensor malfunction in automated guided vehicles (AGVs) are complex and expensive, lacking a cost-effective, simple, and reliable solution for real-time detection.
Innovation Solution
A method utilizing redundant wheel and steering sensor data from multiple pairs of wheel units to calculate motion variables and detect malfunctions by comparing differences, with threshold values set based on normal fluctuations, enabling immediate and accurate identification of sensor malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety-rated sensors are used to detect sensor malfunction, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The system uses its own existing wheel sensors and steering sensors to detect malfunctions by monitoring inconsistencies in sensor data, rather than introducing separate safety-rated sensors. The control system performs self-diagnosis by calculating motion values from different sensor pairs and comparing them to identify malfunctions.
Solution Approach 2:
The control system continuously monitors sensor data from wheel sensors and steering sensors, calculates motion values, compares results from different sensor pairs, and provides feedback when inconsistencies indicate sensor malfunction. This closed-loop monitoring enables real-time detection without additional hardware.
2Reliability
If sensor redundancy is introduced by adding two-wheel sensors and two-steering sensors per wheel unit, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The existing wheel sensors and steering sensors serve dual purposes: they provide motion control data for normal operation and simultaneously serve as diagnostic tools for detecting sensor malfunctions. The same sensors are used for both control and safety functions.
Solution Approach 2:
The system leverages its existing sensor infrastructure to perform self-diagnosis, using the redundant information from multiple sensor pairs to detect malfunctions without requiring additional dedicated safety sensors.
3Measurement precision
If traditional sensor redundancy methods are used, then detection accuracy is improved, but ease of operation deteriorates due to complicated implementation
Solution Approach 1:
The motion calculation and sensor malfunction detection functions are merged into a single integrated process within the control system. The same computational routine that calculates motion values also performs the comparison and malfunction detection, eliminating the need for separate detection systems.
Solution Approach 2:
The control system automatically performs malfunction detection as part of its normal operation, requiring no additional manual intervention or complex external monitoring systems.
Data Source
AI summary
A method of detecting sensor malfunction in an automated guided vehicle, AGV, including for at least two different pairs of wheel units in a motion state of the AGV, calculating a motion value for at least one motion variable of a body of the AGV based on sensor data from a wheel sensors and/or a steering sensors; for at least one motion variable, calculating a difference between the motion values for at least two different pairs; and determining that there is a malfunction in one or more of the wheel sensors and the steering sensors if one of the at least one difference exceeds a threshold value associated with the respective motion variable.