Ultrasonic Sensor Blocked State Detection Using Distance Thresholds
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Solution Overview
Problem
Existing methods for detecting a blocked state of ultrasonic sensors in motor vehicles, such as those covered by dirt, ice, or snow, often result in false positives due to influences from nearby objects, which can lead to incorrect classification of the sensor's functionality and reduced availability for actual measurements.
Innovation Solution
A method that records at least one oscillation parameter of the ultrasonic sensor, such as decay time or resonant frequency, and uses a detection algorithm to evaluate these parameters, with a threshold-based approach to ignore the detection of a blocked state when an object is very close, preventing false classifications by assuming a non-blocked state in such situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oscillation parameters are evaluated to detect blocked state, then detection capability is improved, but false detection rate increases due to nearby objects
Solution Approach 1:
The patent introduces a distance check as an intermediary step between oscillation parameter evaluation and blocked state determination. By measuring the distance to nearby objects and comparing it with a threshold value, the system determines whether to trust the oscillation parameter evaluation. This intermediary mechanism prevents false detections when objects are in the near field, while maintaining accurate blocked state detection when objects are farther away.
2Reliability
If detection algorithm is continuously executed, then detection reliability is improved, but processing time and energy consumption increase
Solution Approach 1:
The patent implements periodic execution of the detection algorithm based on distance conditions. Instead of continuous execution, the algorithm is triggered periodically when distance to objects exceeds the threshold value. This periodic approach maintains detection reliability by regularly checking blocked state when conditions are favorable, while reducing unnecessary processing when objects are in the near field.
3Measurement precision
If threshold value is set low, then detection sensitivity is improved, but false positives increase from nearby objects
Solution Approach 1:
The patent applies dynamic adjustment of the detection threshold based on distance to nearby objects. The threshold value is not fixed but adapts according to the measured distance: when objects are far away, a lower threshold provides high sensitivity; when objects are nearby, the threshold is effectively raised by blocking the detection algorithm, preventing false positives. This dynamic approach optimizes both sensitivity and reliability across different operating conditions.
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 minimizes false detection rates and ensures the ultrasonic sensor is not incorrectly marked as blocked when an object is near, allowing for precise measurement of the decay time without distortion from target echoes, thus maintaining sensor reliability and reducing driver alerts unnecessarily.
Implementation Method 1
ultrasonic sensor (3) which is designed to detect objects in an area surrounding the motor vehicle (1) and to record distances
Implementation Method 2
the ultrasonic waves (target echo) reflected by the object
Implementation Method 3
the so-called decay time of the diaphragm of the ultrasonic sensor
Implementation Method 4
recording a current actual value of the decay time of the ultrasonic sensor (3)
Implementation Method 5
the resonant frequency of the ultrasonic sensor is measured and is compared with stored reference values
Implementation Method 6
the resonant frequency of the ultrasonic sensor is a direct indicator of soiling, a layer of ice or snow, since this additional layer influences the mass of the harmonic oscillation
Data Source
AI summary
The invention relates to a method for detecting a blocked state of an ultrasonic sensor (3) of a motor vehicle (1), in which at least one oscillation parameter of the ultrasonic sensor (3) is recorded and an evaluation device (4) of the motor vehicle (1) carries out a detection algorithm which is used to evaluate the at least one oscillation parameter for the purpose of detecting the blocked state. An object (9) in an area surrounding the motor vehicle (1) is detected by the evaluation device (4) on the basis of sensor data from at least one sensor (3, 8) of the motor vehicle (1), in which case, when a distance (D) between the object (9) and the ultrasonic sensor (3) falls below a predefined threshold value (G), the detection algorithm is not carried out by the evaluation device (4) or a blocked state of the ultrasonic sensor (3), as detected using the detection algorithm, is ignored by the evaluation device (4).