Metrology System Using Time-of-Flight Sensor for 6DoF Tracking
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Solution Overview
Problem
Existing laser trackers require complex and voluminous systems for accurate 6DoF determination of objects, necessitating stable HeNe laser calibration and stabilization, which is energy-consuming and complex.
Innovation Solution
A metrology system that omits the need for a laser source, using a time-of-flight sensor with a zoom objective and illumination unit, to track and measure objects with high precision, allowing for a more compact and less complex design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a HeNe laser is used for distance measurement in laser trackers, then measurement range and coherence length are improved, but device complexity, volume, and energy consumption increase due to required calibration and stabilization components
Solution Approach 1:
The patent extracts and removes the HeNe laser source from the distance measuring device, replacing it with a compact laser diode. This extraction eliminates the need for complex calibration and stabilization components associated with HeNe lasers, thereby reducing device complexity while maintaining measurement precision through the alternative laser diode approach
Solution Approach 2:
The patent changes the laser source parameter from HeNe laser to laser diode, fundamentally altering the system architecture. This parameter change enables a shift from complex calibration-based systems to simpler systems that rely on different measurement principles, reducing overall device complexity while preserving measurement capabilities
2Measurement precision
If a HeNe laser is used for distance measurement, then measurement range is improved, but device volume and energy consumption increase
Solution Approach 1:
The patent extracts the energy-intensive HeNe laser from the system and replaces it with a low-power laser diode. This extraction significantly reduces energy consumption while maintaining the essential distance measurement functionality through alternative technical approaches
Solution Approach 2:
The patent employs a laser diode that consumes minimal energy compared to the HeNe laser, effectively replacing an energy-intensive component with a more efficient alternative that achieves the same measurement goals with substantially lower power requirements
3Reliability
If complex calibration and stabilization components are added to use a HeNe laser, then measurement stability is improved, but device complexity and volume increase
Solution Approach 1:
The patent removes the need for bulky calibration and stabilization components by extracting the HeNe laser from the system. The alternative laser diode approach inherently eliminates the requirement for these additional components, achieving measurement stability through different means while reducing device volume
Solution Approach 2:
The patent substitutes the mechanical calibration and stabilization systems required by HeNe lasers with an electronic/software-based approach using a laser diode. This substitution eliminates physical calibration components and stabilization mechanisms, thereby reducing device volume while maintaining measurement reliability
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 system achieves accurate and precise 6DoF determination of objects without the need for complex laser calibration, resulting in a more efficient and stable metrology solution.
Implementation Method 1
a distance measuring device configured to provide distance data with respect to the target object
Implementation Method 2
an illumination unit and a time-of-flight sensor (ToF)... emitting illumination light towards the target object along an optical axis
Data Source
AI summary
A metrology system comprising a target object, a metrology instrument and a control unit configured for controlling an alignment of the targeting unit and for deriving an orientation of the target object. The metrology instrument comprises a zoom objective, an illumination unit and a time-of-flight sensor comprising an array of pixels and capable of providing range data for each pixel of the array as point cloud data, the time-of-flight sensor provides the distance measuring device. The control unit comprises an object determination functionality which provides receiving the point cloud data provided by the time-of-flight sensor, deriving a digital representation of the target object by processing the point cloud data, comparing the digital representation of the target object with a reference pattern of the target object, and determining the orientation of the target object based on the comparison of the digital representation of the target object with the reference pattern.