Wear Element Fall Detection Using Accelerometer Rotational Position
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Solution Overview
Problem
Existing methods for detecting fallen wear elements in earth moving machines are unreliable, particularly when elements fall close to the machine or inside the shovel, leading to operational inefficiencies, financial losses, and safety risks due to manual intervention in grinders.
Innovation Solution
A fall detection method using three-axis accelerometers to determine rotational position measurements of wear elements relative to reference axes, comparing these measurements to establish a mean reference value and detecting deviations that indicate a fall, allowing for accurate detection without reliance on connection loss signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radiofrequency transmitters and receivers are used to detect wear element falls, then detection capability is improved, but false negatives occur when elements fall close to the machine or inside the shovel
Solution Approach 1:
The patent replaces the radiofrequency electromagnetic detection system with an accelerometer-based mechanical detection system. Each wear element contains an accelerometer that detects gravitational acceleration changes when the element falls, providing reliable detection regardless of proximity to the machine. This mechanical approach substitutes the electromagnetic field-based method and eliminates false negatives caused by signal persistence near the machine.
Solution Approach 2:
The wear elements perform self-detection of their own fall state through onboard accelerometers. Each element independently monitors its own gravitational acceleration and determines whether it has fallen, without requiring external receivers or transmitters. This self-service approach ensures that fall detection is not compromised by the element's position relative to the machine.
2Device complexity
If connection loss detection is used to identify fallen elements, then system complexity is reduced, but detection fails when elements fall inside the shovel or close to the machine
Solution Approach 1:
The patent replaces the connection-based detection method with a physics-based accelerometer measurement system. Instead of monitoring radiofrequency connection status, the system measures gravitational acceleration directly at each wear element. This substitution provides reliable fall detection because the physical principle of gravity detection remains valid regardless of the element's position, eliminating the reliability issues of connection loss methods.
Solution Approach 2:
The patent changes the detection parameter from radiofrequency connection status to gravitational acceleration magnitude. By monitoring the g-force experienced by each wear element, the system can reliably detect falls based on the characteristic acceleration pattern when an element detaches and falls, providing consistent detection performance independent of position.
3Measurement precision
If manual inspection is performed to verify wear element status, then detection accuracy is improved, but operational time is lost and safety risks increase
Solution Approach 1:
The accelerometer-based detection system operates continuously, monitoring gravitational acceleration at each wear element without interruption. This continuous monitoring provides real-time fall detection, eliminating the need for periodic manual inspections. The useful action of detection continues uninterrupted, maintaining high accuracy while maximizing machine operational time and eliminating safety risks associated with manual intervention.
Solution Approach 2:
The wear elements continuously self-monitor their own status through onboard accelerometers, providing ongoing verification of their attached state without requiring external inspection. This continuous self-service detection maintains high measurement precision while eliminating time loss and safety risks associated with manual verification.
4Reliability
If wear elements are monitored using proximity sensors, then partial detachment can be identified, but the system cannot detect falls when elements land inside the shovel
Solution Approach 1:
The patent replaces proximity sensor-based monitoring with accelerometer-based detection. While proximity sensors monitor attachment status, they cannot detect when an element has fallen and landed inside the shovel. Accelerometers directly measure the gravitational acceleration event of the fall itself, providing ease of operation for detecting fallen elements regardless of their final position, while maintaining reliable attachment status monitoring.
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
This method enables reliable detection of fallen wear elements even when they fall close to the machine, reducing false positives and enabling the use of more powerful radiofrequency links for localization, thus improving operational efficiency and safety.
Implementation Method 1
each wear element being provided with a sensor comprising a three-axis accelerometer
Implementation Method 2
determining a mean reference value based on said rotational position measurements of each of said wear elements
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to a fall detection method, corresponding system and machine, for detecting the fall of a wear element (1) provided with a three-axis accelerometer (3) of an earth moving machine (2) with the following steps: - obtaining an accelerometer measurement (100) of each wear element (1); - determining a rotational position measurement (102) of each wear element (1) with respect to the reference axis (4) based on its accelerometer measurement (100); - determining a mean reference value (103) based on all the rotational position measurements (102); - determining a deviation value (104) of each wear element (1) based on the deviation between its rotational position measurement (102) with respect to the mean reference value (103); - determining that there is a fall of a wear element (1) if its deviation value (104) exceeds a threshold value (105); and - repeating the steps in an iterative manner.