Ultrasonic Sensor Blockage Detection via Probability Value
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting a blocked state of ultrasonic sensors in motor vehicles, such as those covered by ice, snow, or dirt, are unreliable due to variations in vibration parameters and often result in false negatives or time delays in sensor availability.
Innovation Solution
A method that calculates a probability value based on multiple measured variables from different sensors, such as temperature, weather conditions, and geographic location, to adjust the sensitivity of the detection algorithm for the ultrasonic sensor's vibration parameters, ensuring reliable detection of blockages without errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ultrasonic sensor is switched to a verification mode with significantly increased sensitivity to detect blockages, then the detection capability for blocked state is improved, but the sensor becomes unavailable for actual measurements during verification, resulting in time delay
Solution Approach 1:
The system performs blockage detection by evaluating vibration parameters (resonance frequency, decay time) continuously in the background during normal measurement operations, rather than switching to a separate verification mode. This preliminary continuous monitoring allows the sensor to detect blockages without interrupting its primary measurement function, thus avoiding time delays while maintaining detection capability.
2Reliability
If the detection algorithm is made highly sensitive to vibration parameter changes to detect all blockages, then the detection rate is improved, but false detections increase due to variations in vibration parameters from different body panel materials and nearby objects
Solution Approach 1:
The system stores multiple reference values for vibration parameters (resonance frequency, decay time) that correspond to different body panel materials and configurations. During detection, the system compares current vibration parameters against the appropriate reference values based on the identified body panel type, allowing adaptive threshold adjustment that maintains high detection sensitivity while accounting for legitimate variations in the sensor environment, thus reducing false detections.
Solution Approach 2:
The system continuously monitors vibration parameters and uses the results to adjust detection thresholds dynamically. By evaluating the consistency of vibration parameter changes over time and comparing them against stored reference patterns for different body panel materials, the system can distinguish between actual blockages and normal environmental variations, thereby reducing false detections while maintaining high detection rates.
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 approach allows for accurate and timely detection of blocked ultrasonic sensors, minimizing false positives and negatives, and ensuring continuous obstacle detection functionality.
Implementation Method 1
ultrasonic sensor device (2) configured for carrying out such a method
Implementation Method 2
current actual value of at least one vibration parameter of the ultrasonic sensor is recorded
Implementation Method 3
This method measures the natural frequency or resonance frequency of the ultrasonic sensor and compares it to stored reference values. This method is based on the fact that the resonance frequency of the ultrasonic sensor is a direct indicator of contamination, ice, or snow, as this additional layer affects the mass of the harmonic oscillation.
Implementation Method 4
additional mass can affect the so-called decay time of the ultrasonic sensor's diaphragm
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for detecting a locked state of an ultrasonic sensor (3) of a motor vehicle (1), in which state a current actual value of at least one oscillation parameter of the ultrasonic sensor (3) is sensed and is compared with at least one limiting value by means of an evaluation device (4) in order to detect the locked state, wherein a probability value (W) which specifies the current probability of the locked state of the ultrasonic sensor (3) is determined as a function of a measured variable of at least one sensor (8 to 14) which is different from the ultrasonic sensor (3), and the locked state is additionally detected taking into account the probability value (W).