Absolute Position Detector Curvature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional absolute position detectors using magnetic sensors suffer from degraded code reading accuracy due to the curvature of the absolute code disk, leading to read errors, especially at the ends of the sensor array, which require frequent adjustments and are prone to errors from temperature changes and sensor characteristic variations.
Innovation Solution
An absolute position detector that uses a compensation sensor, located apart from the read sensor by a distance within a range of λ/2 to 3·λ/2, to correct the output signal and prevent bit read errors by adjusting the signal waveform to accurately represent bit information, and also employs a bit value determination circuit that improves the read sensor output signal based on the sum of output signals from multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If magnetic sensors are arranged in a straight line to read absolute code, then the device structure is simple and easy to manufacture, but code reading accuracy is degraded due to curvature effects causing read errors
Solution Approach 1:
A compensation sensor is introduced as an intermediary element to mediate between the read sensor and the absolute code. The compensation sensor detects the actual position information and provides correction data to eliminate read errors caused by curvature effects, thereby improving code reading accuracy without changing the basic linear sensor arrangement structure
Solution Approach 2:
The system implements feedback by using the compensation sensor to continuously monitor position information and feed back correction signals to correct read errors. This feedback mechanism dynamically compensates for accuracy degradation caused by curvature effects during operation
2Length of moving object
If sensors are positioned at the ends of the array to cover the full range, then the detection range is maximized, but read errors increase due to curvature effects at the ends
Solution Approach 1:
Different sensors in the array are assigned different functions based on their local positions. Compensation sensors are strategically placed at specific locations where they can effectively compensate for read errors in adjacent read sensors, creating local quality improvements that address curvature effects at critical positions while maintaining overall detection range
3Measurement precision
If conventional offset correction is applied to sensor signals, then some accuracy improvement is achieved, but read errors still occur especially at bit boundaries
Solution Approach 1:
The compensation sensor performs preliminary detection of position information before the read sensor attempts to read the absolute code. This preliminary action allows the system to pre-calculate correction values that anticipate and prevent read errors at bit boundaries, rather than merely correcting offsets after errors occur
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 proposed solution significantly enhances code reading accuracy by compensating for signal offsets and improving signal waveforms, reducing bit read errors and maintaining accuracy despite sensor characteristic changes.
Implementation Method 1
convert the magnetic flux, which varies in accordance with changes in magnetic resistance generated by the concave and convex portions on the outer peripheries of the code disks composed of magnetic materials, into electric signals by means of components such as magnetic resistor elements and coils
Data Source
AI summary
An absolute position detector for accurately reading a code recorded on an absolute track is provided. Output signals from sensors that read a code recorded on an absolute track are input into a binarization processor. A compensator provided within the binarization processor functions to correct and determine the value of a read target bit based on an output signal from a read sensor which is the sensor located closest to the center of the one-bit width of the read target bit, and an output signal from a compensation sensor, which is a sensor separated from the read sensor by a distance within the range from λ/2 to 3·λ/2.