Sensor Device Alignment Using IMU and LED Feedback

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Solution Overview

Problem

Laser scanners face challenges in precise alignment, particularly in determining angular orientations below 1°, due to the lack of suitable flat surfaces for alignment tools like spirit levels, and existing solutions are not intuitive for adjusting multiple angles in space.

Innovation Solution

A sensor device with an integrated IMU (Inertial Measurement Unit) as an electronic spirit level measures orientation relative to the gravitational field, using a simple display of multicolored LEDs to indicate correct or incorrect alignment, allowing for intuitive correction of the sensor's orientation without additional equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a spirit level is used for alignment, then alignment can be performed with simple tools, but angular accuracy below 1° cannot be achieved due to lack of suitable flat surfaces

Engineering Contradiction:
Improveangular accuracyVSAvoidalignment operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical spirit level system with an electronic orientation sensor (accelerometer-based) that electronically measures orientation relative to the gravitational field. This substitution enables high-precision angular measurement (better than 1°) without requiring flat physical surfaces, while maintaining ease of operation through electronic evaluation and display of alignment status.

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

2Measurement precision

If an electronic spirit level is used, then alignment precision can be improved, but the display is not intuitive for adjusting multiple angles in space

Engineering Contradiction:
Improvealignment precisionVSAvoidintuitiveness of adjustment
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements a feedback system where the electronic orientation sensor continuously monitors the sensor device's orientation, and the control unit provides real-time feedback through a display device (such as an LED ring) that visually indicates alignment status. The display shows whether the device is properly aligned or indicates the direction and magnitude of misalignment, making it intuitive for users to adjust multiple angles in space without requiring interpretation of complex numerical data.

Inventive Principle:
Principle #23Feedback

3Loss of information

If a position sensor is integrated into the laser scanner, then alignment information can be obtained, but the sensor is not calibrated ex works and no relationship exists between the position sensor orientation and the laser scanner orientation

Engineering Contradiction:
Improvealignment informationVSAvoidcalibration complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent performs preliminary calibration action during the alignment process itself. The control unit determines the orientation of the sensor device using the electronic orientation sensor and compares it with the target orientation to calculate alignment deviation. This preliminary determination of the relationship between the position sensor and laser scanner orientation eliminates the need for separate factory calibration, as the calibration is automatically established during the first alignment operation.

Inventive Principle:
Principle #10Preliminary 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

Simplifies on-site alignment of laser scanners by providing immediate visual feedback on alignment status, enabling untrained personnel to correct orientations effectively and ensuring precise alignment without additional measurement tools.

Implementation Method 1

A position sensor, which is embodied, for example, as an IMU (Intertial Measurement Unit) and functions as a type of electronic spirit level, measures its orientation with respect to the gravitational field.

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP3933433B1Sensor device and alignment method
Publication Date: 2022.09.14 SICK AG
  • EP3933433B1 patent drawingFigure 1
  • EP3933433B1 patent drawingFigure 2a~3b
  • EP3933433B1 patent drawingFigure 4a~4b

AI summary

A sensor device (10) is described, comprising a housing (48a-b), a position sensor (44) for determining an orientation, a display device (46a-d) for displaying orientation information, and a control and evaluation unit (40) configured to determine the orientation of the sensor device (10) using the position sensor (44), to compare it with a target orientation, and to display the comparison result by means of the display device (46a-d). The display device (46a-d) has at least three light sources (46a-d) distributed across the housing (48a-b), each light source (46a-d) being capable of assuming at least one first display state for correct orientation and a second display state for incorrect orientation. The control and evaluation unit (40) is configured to display the comparison result by means of display states of the light sources (46a-d).