Interferometric Position Detection Using Spherical Target Alignment
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Solution Overview
Problem
Current methods for determining the spatial position of objects, such as robot grippers, lack the necessary accuracy and require contact or complex alignment procedures, which can be inefficient and prone to errors.
Innovation Solution
A contactless method using interferometric length measurement with a coherent measuring beam and a reference beam, where the measuring beam is focused onto a reflective convex surface to achieve high accuracy by ensuring maximum interference contrast, allowing for continuous tracking and precise distance measurement without requiring alignment with the target object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interferometric measurement is used to achieve high measurement accuracy, then measurement precision is improved, but the measuring beam must be precisely aligned with the target object which increases device complexity and reduces ease of operation
Solution Approach 1:
A spherical target object with a reflective convex surface acts as an intermediary between the measuring beam and the object to be measured. The sphere's center serves as a well-defined reference point that automatically provides the correct alignment when the beam is focused on it, eliminating the need for complex alignment procedures while maintaining interferometric measurement accuracy
Solution Approach 2:
The spherical target object self-aligns the measuring beam through its geometry. When the beam is focused on the sphere's center, the reflective surface automatically returns the beam along the same path, providing self-verification of correct alignment and eliminating the need for external alignment adjustments
2Measurement precision
If the measuring beam is focused onto a reflective convex surface to achieve maximum interference contrast, then measurement precision is improved, but the system requires continuous tracking of the target object which increases device complexity
Solution Approach 1:
The spherical target object serves as an intermediary that facilitates easy tracking. Its well-defined center and symmetric geometry provide clear visual and optical signals for tracking systems to lock onto, reducing the complexity of continuous tracking compared to tracking arbitrary-shaped objects
Solution Approach 2:
The reflective convex surface of the sphere provides strong optical contrast and distinctive visual characteristics that make it easily detectable by tracking cameras and sensors, enabling simple and reliable continuous tracking without complex algorithms
3Ease of operation
If a spherical target object with reflective convex surface is used, then ease of operation is improved due to automatic alignment, but the device requires specific target objects which reduces versatility
Solution Approach 1:
The spherical target object with reflective surface serves multiple functions: it provides automatic alignment, defines a precise measurement point at its center, enables interferometric measurement, and facilitates easy tracking. This multi-functionality in a single simple component improves ease of operation while maintaining versatility through the universal applicability of spherical targets across different measurement scenarios
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 enables high-resolution, contact-free spatial position detection with a resolution below the wavelength of the radiation used, ensuring accurate and efficient measurement of object positions, even in dynamic systems, by ensuring the measuring beam hits the target object's center, providing maximum interference contrast and optimal measuring accuracy.
Implementation Method 1
the measuring beam is directed onto a target object 40... generating a beam reflected by the target object 40 which interferes with a reference beam 17
Implementation Method 2
an optical unit with a converging lens that collects light... the measuring beam is focused onto a reflective convex surface to achieve high accuracy by ensuring maximum interference contrast
Implementation Method 3
The signal reflected back from the target object 40... the beam reflected by the target object 40 which interferes with a reference beam 17
Data Source
Figure 1
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AI summary
The invention relates to a method for determining the distance to a movable target object and/or the position of said movable target object (40) comprises the steps of directing a coherent, focused measurement beam (25) at the spherical target object (40), which has a convex reflective surface, in such a way that the center of the target object (40) lies at the focus of the measurement beam (25), and determining a distance between the target object (40) and a reference point by interferometrically superposing the measurement beam (40) reflected by the target object (40) with a reference beam (17).