Sensor Abnormality Detection via Heater Temperature Comparison
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Solution Overview
Problem
Snow and frost on a vehicle's sensor cover glass can refreeze and form an ice film that is not removable by the heat wire heater, leading to reduced sensor performance due to the gap between the ice film and the cover glass, causing difficulties in determining sensor abnormalities.
Innovation Solution
A sensor abnormality determining apparatus that includes a detector to measure the temperature of the heater, an estimator to calculate the expected temperature based on vehicle speed and outside air temperature, and a determinator to identify abnormalities by comparing the measured and estimated temperatures, determining if the cover glass is covered with an ice film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a heat wire heater is used to remove snow and frost from the cover glass, then snow and frost can be melted, but refrozen ice may form that is not in contact with the cover glass and cannot be removed by the heater
Solution Approach 1:
The patent introduces an intermediary substance (wash fluid) that is sprayed onto the cover glass to facilitate the removal of refrozen ice. The wash fluid acts as a mediator between the heater and the ice, allowing the ice to be removed even when it is not in direct contact with the heated cover glass surface.
Solution Approach 2:
The patent employs a washing mechanism that uses hydraulic spray to deliver wash fluid onto the cover glass. This pneumatic-hydraulic system enables the removal of ice by spraying fluid that prevents refreezing and facilitates ice detachment, complementing the thermal action of the heater.
2Reliability
If the heater temperature is continuously monitored to detect abnormalities, then sensor performance can be maintained, but the system complexity increases with additional sensors and processing
Solution Approach 1:
The system uses the existing heater and its control unit to perform self-diagnosis. The abnormality determination unit utilizes temperature data already being collected by the heater control for operational purposes, adding the abnormality detection function without requiring separate dedicated sensors or complex additional hardware.
Solution Approach 2:
The heater control unit is designed to perform multiple functions: it controls the heater operation for snow and frost removal, monitors temperature for operational efficiency, and determines abnormalities by comparing expected versus actual temperatures. This multi-functionality reduces overall system complexity.
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
Effectively determines sensor abnormalities caused by ice films or other obstructions on the cover glass, ensuring the sensor's performance is maintained by identifying temperature discrepancies and potentially triggering the washer to remove ice or debris.
Implementation Method 1
a heat wire heater...configured to remove snow and frost, which are attached to the cover glass, by operating the heat wire heater
Implementation Method 2
an ultrasonic vibrator on a cover glass for covering front faces of a light emitter and a light receiver of a laser radar, and that is configured to remove snow and frost
Data Source
AI summary
A sensor abnormality determining apparatus is configured to determine an abnormality in a sensor apparatus, which is used to recognize a surrounding environment of a vehicle and which includes a heater for heating a cover. The sensor abnormality determining apparatus is provided with: a detector configured to detect a temperature of the heater; an estimator configured to estimate a temperature of the heater on the basis of a speed of the vehicle and an outside air temperature; and a determinator configured to determine an abnormality in the sensor apparatus on the basis of the detected temperature and the estimated temperature.