Absolute Position Sensor With Dual Vernier Code Tracks
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Solution Overview
Problem
Existing encoder devices face challenges in scalability and adaptation to different measuring lengths and diameters, requiring multiple scanning devices and incurring high manufacturing and storage costs due to the limited gradation and scalability of common absolute codes.
Innovation Solution
A sensor device with two parallel code tracks, each with individual codes of different segment lengths, employs the vernier principle to determine the absolute position, allowing easy adjustment of code length by omitting or adding segments while maintaining resolution, and using the same scanning device for various measuring lengths and diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the physical length of the code track is changed to adapt to different measuring lengths, then the adaptability to different applications is improved, but the scanning device must be adapted which increases device complexity and manufacturing costs
Solution Approach 1:
The code track is divided into multiple code track segments that can be independently selected and combined. Different numbers and arrangements of segments create code tracks of different lengths while using the same scanning device, resolving the contradiction between adaptability and device complexity
Solution Approach 2:
A single scanning device is designed to scan multiple code tracks with different lengths by reading sequences of code track segments. This universal scanning device can accommodate various measuring lengths without requiring adaptation, reducing device complexity while maintaining versatility
2Measurement precision
If the number of code elements to be detected changes when jumps between binary resolutions, then the measurement precision is maintained, but the measuring standard and scanning device require changes which increases manufacturing costs
Solution Approach 1:
The code is segmented into multiple code track segments with fixed, predetermined lengths. The scanning device detects a sequence of these standardized segments, maintaining measurement precision while avoiding the need to change the scanning device when jumping between binary resolutions
Solution Approach 2:
Instead of changing the scanning device when jumping between binary resolutions, the system changes the number and arrangement of code track segments selected. This parameter change approach maintains precision while simplifying manufacturing by keeping the scanning device constant
3Adaptability or versatility
If a manufacturer maintains a large number of different measuring elements and scanning devices, then the adaptability to different applications is improved, but the manufacturing and storage costs increase as well as logistical complexity
Solution Approach 1:
A single universal scanning device is designed to scan multiple types of code tracks with different lengths and resolutions by reading sequences of standardized code track segments. This eliminates the need to maintain multiple different scanning devices, reducing quantity while preserving adaptability to different applications
Solution Approach 2:
Different code track segments have different local characteristics (lengths, patterns) optimized for specific resolution requirements. The universal scanning device reads these locally optimized segments while maintaining the same overall device structure, enabling application-specific customization without multiplying the scanning device inventory
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
Enables flexible adaptation of encoder devices to different applications without needing separate scanning devices, reducing manufacturing costs and logistical complexity by maintaining resolution through the vernier principle.
Implementation Method 1
Various technologies are used for the underlying sensor principles, particularly optical, magnetic, capacitive, or inductive. For example, the measuring scale can have a structure consisting of transparent and non-transparent areas, and the scanning device can comprise a light-sensitive sensor arrangement.
Implementation Method 2
Magnetic encoder devices, for example, using a Hall sensor, detect corresponding magnetic structures of the measuring scale.
Data Source
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AI summary
A transmitter device (11) for determining an absolute position (39) of a first object relative to a second object, comprising a scale (15) arranged on the first object, a scanning device (19) connected to the second object for scanning the scale (15), and an evaluation unit (21) connected to the scanning device (19), wherein the scale (15) has an absolute code with a predetermined overall resolution, and the evaluation unit (21) is configured to determine the absolute position (39) by reading a codeword (37) of the absolute code from signals received by the scanning device (19), wherein the scale (15) comprises at least a first code track (17) and a second code track (18), preferably running parallel to it, and the scanning device (19) is configured for jointly scanning the code tracks (17, 18), wherein the code tracks (17,18) each have individual codes with predefined individual code resolutions and the sum of the individual code resolutions is equal to the predefined overall resolution of the absolute code, wherein the first code track (17) and the second code track (18) each comprise sequences of several identical code track segments (27, 29), wherein the code track segments (27) of the first code track (17) are longer or shorter than the code track segments (29) of the second code track (18), and wherein the evaluation unit (21) is configured to combine a codeword (35) of the first individual code with a codeword (36) of the second individual code to determine the codeword (37) of the absolute code, wherein the sequences of several identical code track segments (27, 29) have different track lengths and a global null word (25) or a global one word is provided to compensate for the difference (45) is appended to or inserted into the shorter sequence.