Position Measuring Device Aperiodic Code Signal Processing
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Solution Overview
Problem
Existing position measuring devices face challenges in achieving high resolution due to the limitations of absolute position information derived from pseudo-random codes, requiring additional incremental position measurements and complex Fourier analysis, which increases computational demands and complicates real-time processing.
Innovation Solution
A position measuring device that derives incremental position information from a serial code with aperiodically arranged code elements, using a converter device to generate periodic incremental signals independent of code element periodicity, allowing for simple and reliable generation of absolute and incremental position information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pseudo-random code with periodic subfields is used to generate incremental position information, then absolute position information can be obtained, but a third state is required for coding the code elements, increasing device complexity
Solution Approach 1:
The patent extracts the periodicity requirement from the code structure itself and relocates it to the signal processing stage. The code elements can be arranged aperiodically in the spatial domain, while the incremental signal is made periodic through digital signal processing techniques, specifically by selecting and combining scanning signals to create a synthetic periodic waveform.
Solution Approach 2:
The patent replaces the need for physical periodic code structures with a computational approach. Instead of requiring periodic physical arrangements of code elements, the system uses digital signal processing to synthesize periodic incremental signals from the scanning data, substituting mechanical periodicity with computational periodicity.
2Measurement precision
If Fourier analysis is used to determine incremental position information from a serial code, then position measurement can be performed, but relatively high computing power is required and real-time processing is difficult to implement
Solution Approach 1:
The patent employs simpler, computationally inexpensive signal processing methods that can be executed quickly and discarded for each new measurement cycle. Instead of using computationally intensive Fourier analysis, the system uses basic signal combination and period detection algorithms that require minimal processing power and can be rapidly repeated in real-time.
Solution Approach 2:
The patent applies a simplified version of signal analysis that processes only the essential features needed for incremental position determination. Rather than performing a complete Fourier analysis of all signal components, the system focuses on detecting the fundamental periodicity and relevant harmonics, performing just enough analysis to extract the needed position information efficiently.
3Measurement precision
If the resolution of absolute position information is increased by combining with multiple incremental graduations of different graduation periods, then high resolution can be achieved, but the device complexity increases due to requiring several incremental divisions
Solution Approach 1:
The patent makes the single serial code serve multiple functions simultaneously. The same code structure that provides absolute position information also generates incremental position information through the scanning signal processing. This multi-functionality eliminates the need for separate incremental graduations, as the code itself is used for both absolute and incremental measurement purposes.
Solution Approach 2:
The patent merges the absolute and incremental position measurement functions into a single integrated system. Instead of having separate code tracks for absolute and incremental measurements, the system combines both functionalities into one serial code, using the scanning signals from this single code to derive both types of position information through unified signal processing.
Data Source
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AI summary
The invention relates to a position measuring device, wherein, on the one hand, a code word (CW) defining the absolute position and, on the other hand, a periodic incremental signal (IN) are derived from a serial code (1). In order to generate an incremental signal (IN), an arrangement (11) is provided which converts the scanning signals (A1 to A8) in such a manner that the incremental signal (IN) is produced by adding up the converted scanning signals (TA1 to TA8). Advantageously, this conversion leads to the formation of a difference signal by comparison of the scanning signal (A1 to A8) to a reference signal and to a rectification of the difference signal.