Ultrasonic Sensor Temperature Compensation for Stable Distance Sensing
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Solution Overview
Problem
Existing ultrasonic sensors in vehicles face sensitivity issues due to temperature variations, which affect the accuracy of distance measurements, and existing temperature compensation methods are inadequate.
Innovation Solution
A method involving obtaining calibration data for ultrasonic sensors at different temperatures, determining the current membrane temperature, and adjusting the electric current and gain to compensate for temperature-dependent sensitivity changes, thereby optimizing the sensor's performance across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation is performed using existing methods (temperature sensor with fixed thresholds or observing membrane vibrations), then some temperature adjustment is achieved, but the sensitivity accuracy across wide temperature ranges remains insufficient
Solution Approach 1:
The patent implements dynamic sensitivity adjustment by continuously adapting the evaluation threshold based on detected membrane temperature. Instead of using fixed thresholds, the system dynamically modifies the evaluation threshold for echo signal recognition according to the current temperature, enabling accurate measurements across wide temperature ranges from -40°C to +85°C.
Solution Approach 2:
The patent changes the evaluation parameter (threshold) based on temperature conditions. By storing multiple evaluation thresholds corresponding to different temperature ranges and selecting the appropriate threshold based on detected membrane temperature, the system maintains high measurement accuracy across varying thermal conditions.
2Measurement precision
If the evaluation threshold is fixed for all temperatures, then the device complexity is low, but the measurement precision deteriorates at temperatures deviating from reference conditions
Solution Approach 1:
The patent performs preliminary action by pre-storing multiple evaluation thresholds corresponding to different temperature ranges in memory before actual operation. When the ultrasonic sensor operates, the system simply retrieves the appropriate pre-calculated threshold based on detected temperature, avoiding complex real-time calculations while maintaining high precision.
Solution Approach 2:
The patent replaces complex mechanical or computational temperature compensation mechanisms with a simplified electronic lookup approach. Instead of using complex algorithms or additional hardware components, the system substitutes a memory-based threshold selection mechanism that achieves high precision with minimal complexity.
3Adaptability or versatility
If multiple evaluation thresholds are stored for different temperatures, then the adaptability to temperature variations improves, but the storage requirements and processing complexity increase
Solution Approach 1:
The patent applies partial action by storing evaluation thresholds for representative temperature ranges rather than for every possible temperature value. The system divides the temperature spectrum into discrete ranges (e.g., -40°C to -20°C, -20°C to 0°C, etc.) and stores one threshold per range, achieving comprehensive temperature coverage with minimal data storage.
4Reliability
If the membrane temperature deviates from reference temperature (23°C), then the sensitivity changes, but existing compensation methods cannot maintain consistent performance across the entire temperature spectrum
Solution Approach 1:
The patent implements feedback by continuously detecting the membrane temperature using a temperature sensor and using this information to select the appropriate evaluation threshold. The system forms a closed-loop control where temperature detection feeds into threshold selection, which in turn maintains consistent echo signal recognition accuracy despite temperature variations.
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
The method enhances the accuracy and robustness of ultrasonic sensors by effectively compensating for temperature-induced sensitivity variations, ensuring consistent and precise distance measurements.
Implementation Method 1
The ultrasonic membrane, excited by an exciter element attached to it, emits energy in the form of an ultrasonic signal
Implementation Method 2
The exciter element then detects vibrations of the ultrasonic membrane, which result from an echo signal returning from the vehicle environment
Data Source
AI summary
A method for operating an ultrasonic sensor is disclosed. The ultrasonic sensor includes a membrane and an exciter element for exciting the membrane and for detecting a vibration of the membrane. The method includes obtaining calibration data from a storage unit storing the calibration data. The calibration data includes information about a first frequency response of the ultrasonic sensor in a sending direction depending on a membrane excitation frequency at different membrane temperatures and information about a second frequency response of the ultrasonic sensor in a receiving direction depending on a membrane vibration frequency at different temperatures. The method also includes determining a current membrane temperature, determining a sensitivity of the ultrasonic sensor, and controlling an electric current provided to the exciter element and a gain of the ultrasonic sensor based on a difference between the determined sensitivity and a prestored sensitivity.