Lidar Alignment via Automated Calibration on Mobile Robots

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Solution Overview

Problem

Mobile robots equipped with LIDAR systems often face misalignment issues due to rigid mounting, leading to incorrect obstacle detection and localization problems, as the LIDAR plane may not align properly with the floor, causing the robot to incorrectly interpret the floor as an obstacle and struggle with accurate localization on non-vertical surfaces.

Innovation Solution

An automated calibration method using the mobility of the robot to capture LIDAR measurements from different angles and distances relative to a calibration target, processing these measurements to determine calibration data and generate alignment instructions for adjusting the LIDAR units, ensuring proper alignment and preventing misinterpretation of the environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If LIDAR units are rigidly mounted to the robot base, then the mounting is simple and stable, but the LIDAR plane becomes misaligned with the floor, causing incorrect obstacle detection

Engineering Contradiction:
Improvemounting stabilityVSAvoidobstacle detection accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The system changes the operational parameters by introducing dynamic alignment compensation through software algorithms that adjust LIDAR data based on detected floor orientation, transforming a static misaligned mounting into a functionally aligned system through parameter adjustment

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical alignment approach (physically adjusting the LIDAR mounting angle) with an informational/substitution approach using camera-based floor detection and software-based orientation correction to achieve proper alignment without mechanical modification

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

2Ease of manufacture

If LIDAR units are rigidly mounted to the robot base, then the installation is simple, but localization accuracy on non-vertical surfaces deteriorates

Engineering Contradiction:
Improveinstallation simplicityVSAvoidlocalization accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The system substitutes mechanical alignment adjustments with a vision-based detection system and software processing that automatically determines and compensates for the correct orientation, maintaining installation simplicity while achieving high localization accuracy

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

Solution Approach 2:

The camera acts as an intermediary device that captures visual information about the floor and environment, which is then processed to provide orientation data that compensates for the rigid mounting, serving as a mediator between the fixed LIDAR and the variable environment

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If manual calibration methods are used for LIDAR alignment, then alignment can be adjusted, but the calibration process is time-consuming and requires human intervention

Engineering Contradiction:
ImproveLIDAR alignment accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system implements self-service calibration where the robot autonomously performs the entire calibration process using its own camera and LIDAR sensors to detect the calibration target, calculate orientation, and generate correction parameters without human intervention, making the system self-calibrating

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The calibration process uses feedback loops where the camera detects the calibration target, the system processes the images to determine orientation, and the results are used to generate alignment correction parameters, creating a closed-loop automated calibration system

Inventive Principle:
Principle #23Feedback

4Reliability

If the LIDAR plane is misaligned with the floor, then the robot may detect the floor as an obstacle, but correcting this requires complex manual adjustment procedures

Engineering Contradiction:
Improveobstacle detection reliabilityVSAvoidalignment adjustment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical adjustment procedures with automated vision-based detection and software-based orientation calculation, substituting manual mechanical alignment with an automated informational processing system that determines and applies the correct alignment parameters

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

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 method reduces the time and human intervention required for LIDAR calibration, improves the accuracy of obstacle detection and localization, and allows the robot to operate more effectively in its environment by ensuring the LIDAR units are correctly aligned.

Implementation Method 1

transmit laser light and detect light reflected from objects in the environment

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

capturing a plurality of LIDAR measurements including a first set of LIDAR measurements as the mobile robot spins in a first direction at a first location, the first location being a first distance to a calibration target, and a second set of LIDAR measurements as the mobile robot spins in a second direction at a second location

Methodology Applied
Scientific EffectMobility-based position change:

Data Source

PatentUS20240210542A1Methods and apparatus for lidar alignment and calibration
Publication Date: 2024.06.27 BOSTON DYNAMICS INC
  • US20240210542A1 patent drawing
  • US20240210542A1 patent drawing
  • US20240210542A1 patent drawing

AI summary

Methods and apparatus for automated calibration for a LIDAR system of a mobile robot are provided. The method comprises capturing a plurality of LIDAR measurements. The plurality of LIDAR measurements include a first set of LIDAR measurements as the mobile robot spins in a first direction at a first location, the first location being a first distance to a calibration target, and a second set of LIDAR measurements as the mobile robot spins in a second direction at a second location, the second location being a second distance to the calibration target, wherein the first direction and the second direction are different and the second distance is different than the first distance. The method further comprises processing the plurality of LIDAR measurements to determine calibration data, and generating alignment instructions for the LIDAR system based, at least in part, on the calibration data.