Ultrasonic Sensor Temperature Compensation for Exhaust Heat Interference
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Solution Overview
Problem
The accuracy of ultrasonic object detection in vehicles is compromised by temperature variations, particularly due to inaccurate temperature measurements from outside air temperature sensors affected by engine exhaust heat, leading to incorrect sensor sensitivity settings.
Innovation Solution
An ultrasonic object detection apparatus with a sensor temperature detector to adjust detection sensitivity and object detection thresholds based on ambient temperature, ensuring accurate object detection by selecting a sensitivity correction temperature close to the actual outside air temperature, thereby minimizing the impact of temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the outside air temperature sensor is used to acquire temperature data for sensitivity correction, then the sensitivity setting can be adjusted based on temperature, but the temperature measurement becomes inaccurate due to engine exhaust heat and sensor malfunction
Solution Approach 1:
The patent introduces an intermediary approach by using the transceiver's own temperature detection capability as a mediator between the harmful engine heat environment and the required accurate temperature measurement. The transceiver includes a temperature detection circuit that measures the actual temperature at the sensor location, serving as an intermediary measurement that reflects the true outside air temperature despite the harmful thermal environment.
Solution Approach 2:
The transceiver performs self-service by detecting its own temperature using an integrated temperature detection circuit. This self-measurement capability allows the system to acquire accurate temperature data directly from the transceiver location without relying on external temperature sensors that are vulnerable to engine exhaust heat interference.
2Device complexity
If the sensitivity setting is based on inaccurate temperature data, then the system can operate with a single temperature sensor, but the object detection accuracy deteriorates due to wrong sensor sensitivity
Solution Approach 1:
The transceiver performs self-service by detecting its own temperature using an integrated temperature detection circuit. This self-measurement capability allows the system to acquire accurate temperature data directly from the transceiver location without relying on external temperature sensors that are vulnerable to engine exhaust heat interference.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the reception sensitivity parameter based on the temperature measurement from the temperature detection circuit. The reception circuit varies its sensitivity setting according to the detected temperature, ensuring optimal object detection accuracy across different temperature conditions without requiring multiple external sensors.
3Reliability
If multiple ultrasonic sensors are mounted to improve detection reliability, then the system can compensate for individual sensor failures, but the device complexity and cost increase
Solution Approach 1:
The transceiver performs self-service by detecting its own temperature using an integrated temperature detection circuit. This self-measurement capability allows the system to acquire accurate temperature data directly from the transceiver location without relying on external temperature sensors that are vulnerable to engine exhaust heat interference.
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 ensures reliable and accurate object detection by maintaining consistent reception gain and object detection thresholds, reducing the likelihood of malfunction and improving detection accuracy across varying temperatures.
Implementation Method 1
at least one transceiver that transmits a transmission wave as an ultrasonic wave to outside of the vehicle and receives a reflection wave of the transmission wave reflected by an object
Implementation Method 2
at least one reception circuit that detects a signal level of the reflection wave received by the transceiver
Implementation Method 3
at least one sensor temperature detector that detects an ambient temperature of the transceiver
Implementation Method 4
a detection sensitivity adjuster that performs a detection sensitivity adjustment, which is an adjustment of at least one of a detection sensitivity of the reception circuit and the object detection threshold, based on the ambient temperature detected by the at least one sensor temperature detector
Data Source
AI summary
An obstacle detection apparatus includes: a transceiver transmitting a transmission wave and receiving an ultrasonic wave; a transmission controller; a receiver circuit detecting a signal level of a receiving wave; a distance calculator sequentially calculating a distance to an object reflecting the transmission wave; a memory storing the distance to the object; an obstacle determination device determining whether the object is an obstacle; and a reception level monitoring device monitoring the signal level of the receiving wave before the transmission wave being transmitted. When the signal level exceeds a predetermined threshold, the obstacle determination device sets a first number of determination data elements to an increased number of determinations for a predetermined period to be used for determining whether the object is the obstacle, as being larger than a second number of determination data elements used when the signal level does not exceed the predetermined threshold.