Variable Interval Light Source Control for Uniform Lidar Scanning

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Solution Overview

Problem

Existing optoelectronic sensors for motor vehicles, such as lidar sensors, face inefficiencies and reliability issues due to periodic activation of light sources, leading to higher measurement density in edge areas and potential over-illumination, which can endanger living beings and prolong measurement cycles.

Innovation Solution

The method involves dynamically controlling the light source of the optoelectronic sensor to vary time intervals between transmission times, synchronizing with the periodic movement of a deflection unit's mirror element, ensuring uniform emission at discrete angular positions and preventing excessive illumination, thereby enhancing measurement efficiency and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the light source is controlled periodically at fixed intervals, then the measurement cycle is simple to implement, but the measurement density becomes uneven with higher density in outer regions and potential over-illumination

Engineering Contradiction:
Improvesimplicity of light source controlVSAvoiduniformity of measurement density
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by transitioning from fixed periodic control to dynamic variable interval control of the light source. The control unit adjusts the time intervals between light pulse transmissions based on the instantaneous angular position and velocity of the mirror, ensuring uniform measurement density across all angular regions while preventing over-illumination in edge areas.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the light source is controlled periodically, then the control mechanism is simple, but the measurement efficiency is reduced due to over-illumination in edge areas and prolonged measurement cycles

Engineering Contradiction:
Improvecomplexity of control mechanismVSAvoidmeasurement efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements feedback by using the control unit to monitor the mirror's angular position and velocity, then adjusting the light source activation intervals accordingly. This closed-loop control ensures optimal measurement density distribution and prevents over-illumination, thereby improving measurement efficiency without requiring complex additional hardware.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If fixed time intervals are used for light transmission, then the control is straightforward, but excessive illumination occurs in edge areas potentially endangering living beings

Engineering Contradiction:
Improvestraightforwardness of controlVSAvoidexcessive illumination to living beings
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by adjusting the light transmission characteristics based on the specific angular region being scanned. The control unit reduces or suppresses light pulse transmission when the mirror is in edge regions where over-illumination could occur, while maintaining normal transmission intervals in central regions, thereby preventing harm to living beings without compromising overall system simplicity.

Inventive Principle:
Principle #3Local quality

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 allows for more efficient and reliable object detection by optimizing measurement cycles, reducing scanning time, and ensuring safer operation by avoiding excessive illumination, particularly in edge areas.

Implementation Method 1

light pulses are emitted by a transmitter and the light pulses reflected by the object are received by a receiver

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The optoelectronic sensor can determine the distance between the vehicle and the object based on the travel time of a light pulse

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3542181B1Method for operating an optoelectronic sensor of a motor vehicle with variable control of a light source, optoelectronic sensor, driver assistance system and motor vehicle
Publication Date: 2022.04.06 VALEO SCHALTER & SENSOREN GMBH
  • EP3542181B1 patent drawingFigure 1
  • EP3542181B1 patent drawingFigure 2~3
  • EP3542181B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for operating an optoelectronic sensor (5) of a motor vehicle (1), wherein light pulses are emitted by a transmitting device (6) in order to detect an object (3) during a measurement cycle, and the light pulses reflected by the object (3) are received by a receiving device (7). A light source (12) of the transmitting device (6) is actuated at specific transmission times (14) in order to emit the light pulses, and the light pulses are deflected by a deflecting unit (13) of the transmitting device (6) within a specified angular range (12). The light source (12) is actuated such that time intervals between the specified transmission times (14) vary.