Actuator Diagnostics Using Statistical Position Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing diagnostic methods for actuators, such as exhaust gas recirculation valves in internal combustion engines, fail to accurately diagnose valve operation when experiencing oscillations or sensor measurement errors, leading to incorrect diagnoses and delayed detection of malfunctions.
Innovation Solution
A statistical diagnostic method that calculates the distribution of position differences between actual and reference values, using population analysis to determine the actuator's operation state, and compares ratios of these differences to reference values to provide a reliable diagnosis, even in cases of oscillations or sensor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed threshold value is used for diagnosis, then the diagnostic method is simple to implement, but it cannot detect valve malfunctions when the valve is subject to oscillations around the threshold value
Solution Approach 1:
The patent changes the diagnostic parameter from a fixed threshold comparison to a statistical analysis of multiple position values. Instead of comparing each position value against a single fixed threshold, the system collects multiple position values during a time delay and analyzes their distribution relative to the threshold, enabling reliable detection even when values oscillate around the threshold.
2Reliability
If the time delay is extended to account for sensor measurement errors, then the diagnostic reliability improves, but the response time for detecting malfunctions increases
Solution Approach 1:
The patent applies partial action by collecting a limited number of position values during a defined time delay period rather than continuously monitoring indefinitely. This allows the system to achieve sufficient diagnostic reliability through a finite sample size, balancing the need for accurate detection with the requirement for timely diagnosis.
3Loss of time
If the time delay is limited to a very low value to enable rapid diagnosis, then the response time improves, but the method becomes very sensitive to sensor signal disturbances such as signal micro-breaks
Solution Approach 1:
The patent merges multiple position measurements taken during the time delay into a single diagnostic evaluation. By combining multiple values and analyzing their collective behavior relative to the threshold, the system achieves both rapid diagnosis (through limited measurement duration) and stability (through aggregated data analysis that filters out individual signal disturbances).
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The invention proposes a method for diagnosing the operation of an actuator comprising an element designed to be moved between extreme positions, involving the steps wherein a position sensor acquires values of the position (P1) of the element of the actuator during a times period (T1) following transmission of a movement instruction aimed at positioning this element in one of said extreme positions, and of calculating the discrepancy (E1) between each acquired position value and a reference position value (PREF) associated with said extreme position. According to the invention, steps of determining the number (NINF) of discrepancy values that are below a threshold value and/or the number of discrepancy values that are above said threshold value and making the diagnosis regarding the operation of the actuator on the basis of said number.