Range Camera Coordinate Measuring for Safe 3D Probe Path Control

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Solution Overview

Problem

Conventional coordinate measuring machines face challenges in accurately and efficiently determining spatial coordinates of complex workpieces without risking damage to the probe head or the workpiece, particularly in fully automated systems, due to the need for precise control of the probe head's movement.

Innovation Solution

A coordinate measuring machine equipped with a range camera and a controller that uses range image data to control the drive mechanism, allowing for non-contact measurement and optimized movement paths based on 3D-position data, enabling faster and more accurate determination of spatial coordinates while minimizing the risk of impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the probe head moves quickly to measurement points, then productivity is improved, but the risk of damage to the probe head or workpiece increases due to impact

Engineering Contradiction:
Improvemeasurement speedVSAvoidrisk of damage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary scanning of the workpiece surface using the range camera to create a 3D model before the actual measurement. This preliminary action allows the probe head to navigate along pre-calculated safe paths, avoiding impact with the workpiece while maintaining high measurement speed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The range camera continuously provides feedback about the workpiece geometry and probe head position. The controller uses this feedback to dynamically adjust the probe head's movement speed and trajectory, ensuring safe operation while maximizing productivity. The real-time feedback loop prevents impact by detecting workpiece features before the probe head reaches them.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the probe head approaches measurement points closely, then measurement precision is improved, but the complexity of controlling the drive mechanism increases

Engineering Contradiction:
Improvecoordinate determination accuracyVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The range camera acts as an intermediary between the probe head and the workpiece. It provides detailed 3D information about the measurement location, allowing the controller to plan precise approach paths without requiring complex real-time control algorithms. The camera data serves as a map that simplifies the control task while enabling high-precision measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the probe head moves slowly to avoid impact, then reliability is improved, but productivity deteriorates

Engineering Contradiction:
Improvesafety of measurementVSAvoidmeasurement efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the probe head's movement speed based on real-time conditions. During approach to measurement points, the speed is reduced to safe levels. During traversal of safe areas, the speed is increased to maximize productivity. This dynamic speed control maintains reliability while improving overall measurement efficiency compared to consistently slow movement.

Inventive Principle:
Principle #15Dynamics

4Productivity

If a range camera is added to provide 3D position data, then productivity and safety are improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidsystem structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The range camera serves multiple functions: it scans the workpiece surface for safety, provides 3D position data for measurement, and generates navigation paths for the probe head. By consolidating these functions into a single device, the system achieves improved productivity and safety without proportionally increasing complexity. The camera's data is reused across multiple control functions.

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

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 enables faster and more accurate determination of spatial coordinates, reduces the risk of damage to the probe head and workpiece, and allows for non-contact measurement, improving the efficiency and precision of the measurement process.

Implementation Method 1

Range imaging in general is known as a technology which is used to produce a 2D-image showing the distance to points in a scene from a specific point. The resulting image which is generally called range image has pixel values which correspond to the distance of the respective target point at the object.

Methodology Applied
Scientific EffectRange imaging:

Data Source

PatentEP2788714B2Coordinate measuring machine having a camera
Publication Date: 2021.12.15 HEXAGON TECH CENT GMBH
  • EP2788714B2 patent drawingFigure 1
  • EP2788714B2 patent drawingFigure 2~3
  • EP2788714B2 patent drawingFigure 4~5

AI summary

A coordinate measuring machine (1) for determining at least one spatial coordinate of a measurement point of an object (15) to be measured, comprising a base (5) and a drive mechanism, adapted to drive a probe head (13) in a manner such that the probe head (13) is capable to move relative to the base (5) for approaching a measurement point, characterised by a first range camera (3, 33) having a range image sensor with a sensor array, wherein the range camera (3, 33) is adapted to be directed to the object (15) for providing a range image (23) of the object (15), and wherein range pixels of the range image are used for creating a point cloud with 3D-positions of target points of the object (15), and a controller, adapted to control the drive mechanism on the basis of 3D-positions of the target points.