Distance Sensor Blindness Detection in Adaptive Cruise Control

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Solution Overview

Problem

Distance sensors in motor vehicles, particularly in adaptive cruise control systems, fail to properly detect vehicles ahead in adverse weather conditions due to lens icing, leading to unreliable speed control and driver discomfort.

Innovation Solution

A method and device that detect sensor blindness by averaging angle values of lost stationary objects, setting a status bit for blindness when angles fall below a threshold, and using temporal filtering to differentiate between temporary and permanent object loss, thereby switching off the speed controller and alerting the driver.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the distance sensor operates in adverse weather conditions (snow, ice), then the lens heater is activated to prevent icing, but the lens becomes covered with ice layers that block detection signals

Engineering Contradiction:
Improvesensor detection reliabilityVSAvoidlens icing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary actions by continuously monitoring detection quality indicators (signal strength, object stability, angular quality) before complete sensor failure occurs. The lens heater is activated preemptively when adverse conditions are detected, and the system switches off ACC before the ice layer completely blocks the sensor, preventing harmful acceleration/deceleration behaviors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously evaluating detection quality indicators and using this information to determine sensor blindness status. The processor monitors signal characteristics, object tracking stability, and detection consistency, then feeds this information back to control the lens heater and ACC status, creating a closed-loop system that adapts to changing weather conditions.

Inventive Principle:
Principle #23Feedback

2Reliability

If the lens heater is activated continuously to prevent icing, then ice formation is reduced, but energy consumption increases

Engineering Contradiction:
Improvesensor clarityVSAvoidlens heater energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of continuous operation, the lens heater is activated periodically based on detected adverse conditions. The system monitors detection quality indicators and activates the heater only when snow or ice conditions are detected, creating a periodic on-demand heating pattern that reduces energy consumption while maintaining sensor clarity when needed.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If multiple detection indicators are monitored to accurately determine sensor blindness, then detection accuracy improves, but system complexity increases

Engineering Contradiction:
Improveblindness detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system monitors multiple detection indicators (signal strength, object stability, angular quality, detection consistency) beyond what a single indicator would provide. This excessive monitoring of partial aspects of sensor performance creates a comprehensive blindness detection algorithm that accurately determines sensor status through pattern recognition across multiple parameters, improving precision despite increased processing requirements.

Inventive Principle:
Principle #16Partial or excessive action

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 prevents undesirable acceleration and deceleration behaviors by reliably determining sensor blindness and switching control to the driver, ensuring safe operation in icy conditions.

Implementation Method 1

The distance sensor is a radar or lidar-based driver assistance system

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

The distance sensor is a radar or lidar-based driver assistance system

Methodology Applied
Scientific EffectLIDAR: LIDAR

Implementation Method 3

Objects are detected by the radar or lidar in consecutive scanning cycles

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

the lens heater is on, snow will hit the sensor, thaw and refreeze before leaving the sensor

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2009462B1Method and device for recognising the state of a distance sensor attached to a motor vehicle
Publication Date: 2010.12.22 ROBERT BOSCH GMBH
  • EP2009462B1 patent drawingFigure 1
  • EP2009462B1 patent drawingFigure 2
  • EP2009462B1 patent drawingFigure 3

AI summary

The invention relates to a method and a device (2) for detecting the condition of a distance sensor (1) mounted on a motor vehicle. When it is snowing or there is snow on the road and the speed-controlled motor vehicle is following a target vehicle at a short distance, an ice layer (19) in the form of an ice ring will cover a lens (17) of the distance sensor (1), despite the lens heater (21) being switched on. This leads to reduced performance of the distance sensor (1). By means of the present method, a corresponding warning message is issued to the driver.