Vehicle Lamp Optical Axis Control Under Vibration and Inclination

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Solution Overview

Problem

Current self-leveling systems for vehicle lamps using acceleration sensors face challenges in achieving high accuracy while aiming to reduce costs and weight, as they often compromise on precision.

Innovation Solution

A control device for vehicle lamps that includes an acceleration sensor sampling acceleration at a non-integral multiple of the vibration frequency of a vibration generating source, and a controlling unit that adjusts the optical axis based on the sampled acceleration, along with a tilt sensor to determine vehicle inclination and adjust the optical axis accordingly, especially when the vehicle is at rest or moving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If an acceleration sensor is used for self-leveling control, then cost and weight are reduced, but measurement precision deteriorates

Engineering Contradiction:
Improveweight of self-leveling systemVSAvoidaccuracy of self-leveling control
Core Design Contradiction:
Weight of stationary objectVSMeasurement precision

Solution Approach 1:

The patent changes the sampling frequency parameter of the acceleration sensor to a non-integral multiple of the vibration frequency, which transforms the measurement approach to avoid vibration interference while maintaining the use of cheaper acceleration sensors instead of expensive tilt sensors

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful vibration signals into beneficial information by sampling at a non-integral multiple frequency, allowing the system to distinguish between vehicle inclination and vibration effects, thereby maintaining measurement precision while using cost-effective acceleration sensors

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Device complexity

If an acceleration sensor is used for self-leveling control, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvecomplexity of self-leveling systemVSAvoidaccuracy of self-leveling control
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent modifies the sampling frequency parameter to a non-integral multiple of the vibration frequency, which simplifies the device by using acceleration sensors instead of complex tilt sensors while maintaining precision through intelligent signal processing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex mechanical tilt sensors with simpler acceleration sensors, using electronic signal processing (frequency-based sampling) to achieve the same measurement precision, thereby reducing device complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the acceleration sensor samples at an integral multiple of the vibration frequency, then data processing is simplified, but measurement precision deteriorates due to vibration interference

Engineering Contradiction:
Improvecomplexity of data processingVSAvoidaccuracy of inclination measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent optimizes the sampling frequency parameter to be a non-integral multiple of the vibration frequency, which eliminates vibration interference in the measurements while maintaining reasonable data processing complexity through systematic sampling

Inventive Principle:
Principle #35Parameter changes

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 enhances the accuracy of self-leveling control for vehicle lamps by reducing the influence of vibration and accurately adjusting the optical axis based on vehicle inclination, thereby improving the alignment of headlights regardless of the vehicle's state.

Implementation Method 1

an acceleration sensor provided in the vehicle lamp and configured to sample an acceleration at a second frequency that is a non-integral multiple of the first frequency

Methodology Applied
Scientific EffectAcceleration sensing: Accelerometer

Implementation Method 2

vehicle lamp provided with a vibration generating source that vibrates at a first frequency

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Data Source

PatentEP4194268B1Control device for a vehicle lamp and a vehicle lamp system
Publication Date: 2023.12.27 KOITO MFG CO LTD
  • EP4194268B1 patent drawingFigure 1
  • EP4194268B1 patent drawingFigure 2
  • EP4194268B1 patent drawingFigure 3

AI summary

A control device (30) for a vehicle lamp (1) is proposed, the control device (30) comprising a receiving unit (34) that receives a signal indicating an output value from a tilt sensor (132) enabled for deriving an angle of inclination of a vehicle (300) relative to a horizontal plane; a controlling unit (36) that outputs an adjustment signal instructing that an optical axis angle (θo) of the vehicle lamp (1) be adjusted with respect to a change in the angle of inclination observed while the vehicle (300) is at rest and either refrains from generating or outputting the adjustment signal or outputs a maintaining signal instructing that the optical axis angle (θo) be maintained with respect to a change in the angle of inclination observed while the vehicle (300) is traveling; and a movement determining unit (46) that determines whether the vehicle (300) has moved while an ignition switch (314) is in an off state, wherein the controlling unit (36) outputs the adjustment signal with respect to a change in the angle of inclination observed while the ignition switch (314) is in an off state if the movement determining unit (46) has determined that the vehicle (300) has not moved and either refrains from generating or outputting the adjustment signal or outputs the maintaining signal with respect to a change in the angle of inclination observed while the ignition switch (314) is in an off state if the movement determining unit (46) has determined that the vehicle (300) has moved.