Conveyor Volume Sensor Calibration with Multi-Orientation Test Object

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Solution Overview

Problem

Traditional manual calibration of sensor systems for conveying equipment is time-consuming and prone to errors, especially when calibrating spatial and velocity sensors, leading to inaccuracies in the calibration of volume measurement systems.

Innovation Solution

A method involving the acquisition of reference data and multiple passes of a cuboid test object through the detection range of spatial and velocity sensors, using a mathematical optimization algorithm to determine the position and orientation of spatial sensors and correspondence factor, thereby automating the calibration process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual static calibration is performed for each sensor individually, then the calibration can be completed with simple equipment, but the calibration process becomes very time-consuming and error-prone

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines the calibration of multiple sensors (spatial sensors and velocity sensor) into a single integrated calibration process. Instead of calibrating each sensor separately as in traditional methods, the system calibrates all sensors simultaneously by evaluating their combined measurement data from multiple measurement runs, significantly reducing calibration time while maintaining accuracy

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from static calibration (where the conveyor system remains stationary) to dynamic calibration (where the conveyor system operates during calibration). Measurement data is collected during actual conveyor operation with objects moving through the detection range, making the calibration process faster and more representative of real operating conditions

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If manual calibration is performed by measuring coordinates of three points for each spatial sensor, then the calibration can be done with minimal equipment, but errors during calibration lead to incorrect velocity sensor calibration requiring multiple repetitions

Engineering Contradiction:
Improvecalibration simplicityVSAvoidcalibration reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where measurement data from multiple runs is continuously evaluated and used to refine sensor calibration parameters. The system compares measured values with reference values and adjusts calibration parameters iteratively, ensuring high reliability and reducing the need for repeated calibration attempts

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The calibration system performs self-calibration by automatically processing measurement data from the conveyor system's own operation. The system uses the objects being conveyed during normal operation as calibration targets, eliminating the need for external calibration equipment and manual intervention while improving reliability

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If individual sensor configuration is performed separately, then each sensor can be calibrated independently, but the overall system calibration becomes complex and time-consuming

Engineering Contradiction:
Improvesensor configuration flexibilityVSAvoidcalibration process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the calibration processes of spatial sensors and velocity sensor into a unified calibration routine. All sensors are calibrated together by evaluating their combined measurement data from multiple runs, simplifying the overall process while maintaining the ability to configure individual sensors as needed

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4650718A1Method for calibrating a sensor system, sensor system and conveying device
Publication Date: 2025.11.19 SICK AG
  • EP4650718A1 patent drawingFigure 1
  • EP4650718A1 patent drawingFigure 2
  • EP4650718A1 patent drawingFigure 3

AI summary

The present invention relates to a method for calibrating a sensor system with at least one spatial sensor (22) and at least one velocity sensor, in particular for calibrating a volume measurement system for conveying equipment.According to the invention, a corresponding method comprises at least the following steps: recording reference data in an empty detection area of ​​the at least one spatial sensor (22) using the at least one spatial sensor (22); conveying a cuboid test object (40) having different side lengths in two different relative positions and orientations through the detection area of ​​the at least one spatial sensor (22) and recording corresponding measurement data; determining an absolute orientation of the at least one spatial sensor (22) and/or a correspondence factor for the velocity sensor based on the determined reference and measurement data using a mathematical optimization algorithm. Furthermore, the present invention also relates to sensor and conveying systems configured for carrying out this method.Preferably, the sensor system comprises two spatial sensors (22) in the form of LiDAR sensors, which are aligned with the conveying surface (F). A velocity sensor is designed as an encoder and integrated into the drive of the conveying device. Preferably, the cuboid test object (40) is conveyed through the detection range of the at least one spatial sensor (22) in a third different relative position and orientation to acquire and evaluate a third set of corresponding measurement data. This results in a different height of the test object (40) for each of the three measurement runs, with each of these three heights corresponding to a side length of the test object. The entirety of the measurement data from these three measurement runs facilitates the calibration of the spatial sensors (40) and/or the velocity sensor.