Dynamic Threshold Sensor Detection for Erratic State Identification
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Solution Overview
Problem
Conventional methods for detecting an erratic sensor fail to distinguish between a sensor in an erratic state and one experiencing expected rapid changes, often resulting in false indications or missed detections due to the use of constant threshold values.
Innovation Solution
A dynamic threshold value is generated based on the variation of an estimated temperature signal from a predictive sensor, allowing for more accurate detection of an erratic sensor state by compensating for rapidly changing operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant threshold value is used for detecting erratic sensors, then the detection method is simple and easy to implement, but it results in false indications when rapid operating changes occur and fails to detect erratic sensors during normal rapid fluctuations
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static constant threshold to a dynamic threshold that adapts to changing operating conditions. The dynamic threshold is generated based on the rate of change of operating parameters (such as torque command rate of change), allowing the detection system to automatically adjust its sensitivity according to the current operational context. This resolves the contradiction by making the threshold responsive to system dynamics, thereby maintaining high detection accuracy without requiring overly complex fixed-threshold adjustment mechanisms.
Solution Approach 2:
The patent implements parameter changes by modifying the threshold parameter based on operating conditions. Specifically, the threshold value is changed dynamically according to the rate of change of torque command or other relevant parameters. When the rate of change is high (indicating normal rapid fluctuations), the threshold is increased to avoid false indications. When the rate of change is low, the threshold is decreased to maintain sensitivity for detecting erratic sensors. This parameter adaptation resolves the contradiction between detection reliability and system complexity.
2Reliability
If the constant threshold value is set low to detect erratic sensors during normal operation, then erratic sensors can be detected, but false indications occur during rapid operating changes
Solution Approach 1:
The patent applies feedback by using the rate of change of operating parameters as feedback information to adjust the threshold dynamically. The system monitors the rate of change of torque command or other operating parameters and uses this feedback to modulate the threshold value accordingly. When the feedback indicates rapid operating changes, the threshold is increased to prevent false indications. This feedback mechanism resolves the contradiction by allowing the system to maintain high detection sensitivity while automatically suppressing false indications during normal rapid fluctuations.
Solution Approach 2:
The patent implements preliminary anti-action by proactively adjusting the threshold before false indications can occur. By monitoring the rate of change of operating parameters in advance, the system anticipates periods of normal rapid fluctuations and pre-adjusts the threshold upward before erratic sensor detection becomes problematic. This preliminary adjustment prevents false fault indications while maintaining the ability to detect actual erratic sensors when operating conditions are stable.
3Object-affected harmful factors
If the constant threshold value is set high to avoid false indications during rapid changes, then false indications are reduced, but erratic sensors are not detected during normal rapid fluctuations
Solution Approach 1:
The patent resolves this contradiction by making the threshold dynamic rather than statically high. The threshold adapts its height based on the rate of change of operating parameters, being high during rapid changes to avoid false indications and low during stable periods to maintain detection capability. This dynamic adjustment ensures both false indication reduction and erratic sensor detection without requiring a permanently high threshold.
Solution Approach 2:
The patent implements parameter changes by varying the threshold parameter according to operating conditions. The threshold is changed from a fixed high value to a variable value that responds to the rate of change of torque command or other parameters. This parameter modulation allows the system to achieve both objectives: reducing false indications during rapid changes while maintaining detection capability during normal operation.
Data Source
AI summary
A system and method for detecting an erratic state of a monitored sensor includes generating a variation value for a monitored signal generated by a monitored sensor and a variation value for an estimated signal estimated based on a predictive signal generated by predictive sensor, where the predictive signal is predictive of the monitored signal. The monitored signal can rapidly fluctuate based on system operating conditions. A dynamic threshold value is generated based on the estimated variation value, and the monitored signal is compared with the dynamic threshold value to determine if the monitored signal is in an erratic state. The detection method is sufficiently sensitive to distinguish between rapid fluctuation of the monitored sensor and an erratic state.