Lidar Self-Test Mechanism for Safety-Critical Reliability

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Solution Overview

Problem

Existing light detection and ranging systems (Lidar) used in safety-critical applications, such as autonomous vehicles, face challenges in ensuring continuous and reliable operation, as malfunctions can lead to false object detection or missed real objects.

Innovation Solution

A Lidar system with an integrated test unit that includes a second light source for sending a test light signal within the system to the photo detector, allowing for continuous testing of the receiving circuit and signal processing units, and enabling synchronization of light signals to prevent interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a Lidar system operates continuously in safety-critical applications, then productivity is improved, but reliability deteriorates due to increased risk of system malfunctions

Engineering Contradiction:
Improvecontinuous operationVSAvoidsystem malfunction risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements preliminary testing of the photo detector and signal processing unit using a test light source before actual operation. The system performs self-diagnostic tests by directing test light signals through the optical path to detect potential malfunctions or degraded performance, allowing corrective action to be taken before safety-critical operations are affected.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback mechanisms where the control unit monitors test results from the photo detector and signal processing unit. When anomalies are detected during testing, the system provides feedback to alert operators or automatically adjust operations, creating a closed-loop monitoring system that maintains reliability during continuous operation.

Inventive Principle:
Principle #23Feedback

2Reliability

If a test unit is added to the Lidar system for continuous testing, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvecontinuous testing capabilityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the test unit with the existing Lidar system architecture by integrating the test light source, optical path, and testing functionality into the overall system structure. The control unit that already manages the main light source and photo detector is also used to coordinate testing operations, reducing the need for separate independent testing equipment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control unit is designed to perform multiple functions: it controls the main light source for normal operation, manages the test light source for diagnostics, coordinates the photo detector during both operational and testing modes, and processes signals from both functions. This multi-functionality reduces the number of separate components needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If light signals are synchronized to prevent interference during testing, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvesignal detection accuracyVSAvoidsynchronization control
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs periodic action by alternating between operational mode and testing mode in a synchronized sequence. The control unit manages timing to ensure that test light signals are sent only when the main light source is not emitting, and that the photo detector is properly configured for testing rather than normal object detection. This periodic switching prevents signal interference while maintaining measurement precision.

Inventive Principle:
Principle #19Periodic 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

The solution ensures continuous and reliable operation of the Lidar system by regularly testing the photo detector and signal processing units, reducing the risk of system malfunctions and enhancing safety in applications like autonomous driving.

Implementation Method 1

a second light source (9) for sending a test light signal (10) within the light detection and ranging system (1) to the at least one photo detector (4)

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

at least one photo detector (4) for receiving a light signal (3) from the surroundings of the light detection and ranging system (1)

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3640671B1Light detection and ranging system and method for operating and testing a light detection and ranging system, particularly for safety relevant applications
Publication Date: 2025.01.29 INTEGRATED DEVICE TECH INC
  • EP3640671B1 patent drawingFigure 1
  • EP3640671B1 patent drawingFigure 2

AI summary

The invention refers to a light detection and ranging system 1, particularly for safety relevant applications, comprising: at least one first light source 2 for sending a light signal 3 to the surroundings of the light detection and ranging system 1; at least one photo detector 4 for receiving a light signal 3 from the surroundings of the light detection and ranging system 1; at least one signal processing unit 5 for receiving and processing the signal of the at least one detector 4 for detecting objects 6 in the surroundings of the light detection and ranging system 1; at least one control unit 7 for controlling, particularly synchronizing, the at least one light source 2, the at least one photo detector 4 and/or the at least one signal processing unit 5; characterized in that the light detection and ranging system 1 further comprises a test unit 8 for testing the at least one photo detector 4 and the at least one signal processing unit 5, wherein the test unit 8 comprises a second light source 9 for sending a test light signal 10 within the light detection and ranging system 1 to the at least one photo detector 4. The invention further relates to a method for operating and testing a light detection and ranging system 1, particularly for safety relevant applications and a light detection and ranging system 1 implementing the method.