Self-Calibrating Angle Detector for Axis Run-Out Measurement
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Solution Overview
Problem
Existing angle detecting devices face challenges in accurately measuring axis run-out, especially at high speeds, due to synchronous and asynchronous angular errors, and are costly when used for multiple axes, with current methods being inefficient and expensive.
Innovation Solution
An angle detecting device with a self-calibration function that uses multiple sensor heads arranged equiangularly on a scale disc, where each sensor head serves as a reference to calculate self-calibration values, phase aligns these values, and extracts asynchronous angular errors by subtracting the average value, allowing for precise axis run-out measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If contact method with electric micrometer is used to measure axis run-out, then measurement can be performed, but it cannot be utilized with high-speed rotation axis
Solution Approach 1:
The patent replaces the mechanical contact measurement method (electric micrometer) with a non-contact optical measurement method using the angle detecting device. The scale disc with scale marks and optical sensors eliminate mechanical contact, enabling measurement of high-speed rotating shafts without the limitations of contact-based methods.
2Loss of time
If capacitance sensor is used for non-contact measurement, then measurement can be performed, but it takes a lot of time to set up because the gap between rotation axis and sensor is narrow
Solution Approach 1:
The patent uses a scale disc that is rotated together with the measurement target shaft, creating a copied rotational motion. The optical sensors detect scale marks on this scale disc, indirectly measuring the shaft's run-out without requiring direct proximity to the rotating shaft itself, thus eliminating the narrow gap setup problem.
3Adaptability or versatility
If laser-type measurement device is used, then measurement can be performed, but the cost is high when two axes are provided
Solution Approach 1:
The patent creates a universal measurement system where a single angle detecting device can measure run-out for multiple axes. By rotating the scale disc with the measurement target shaft and using optical sensors to detect scale marks, the same basic device structure can be applied to different axes (X and Y) without requiring expensive laser devices for each axis.
4Ease of manufacture
If scale marks are written artificially on scale disc, then angle detecting device can be manufactured, but the scale lines are not written equiangularly causing angular error
Solution Approach 1:
The patent employs self-calibration functionality where the angle detecting device automatically detects and corrects its own scale line errors. The calibration function measures the actual positions of scale marks and calculates correction values, allowing the device to compensate for manufacturing imperfections in scale mark positioning without requiring externally calibrated equipment.
Data Source
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AI summary
An angle detecting device with a self-calibration function is also provided with an axis run-out measuring function, so that various kinds of setups to an engine, a drive shaft of an automobile, and the like, can be made readily. The angle detecting device with the self-calibration function is used, in which a plurality of sensor heads is provided with an equiangular interval at a circumference of a scale disc fixed to a rotating shaft, and when one of the sensor heads is selected as a reference sensor head, a sum of measurement differences between the reference sensor head and the other respective sensor heads, and this sum is divided by the number of sensor heads, to determine an average value, whereby a self-calibration value is obtained. Further, a sensor head selected as the reference sensor head is changed to another sensor head in order, and each of the self-calibration values for all the sensor heads is obtained where each of all the sensor heads is adopted as the reference head. Then, each of the self-calibration values is deviated by an angle in terms of arrangement with respect to a particular sensor head, and a phase is aligned to a self-calibration value where the particular sensor head is adopted as the reference head. Then, an average value for all the calculation results of the phase converting is obtained, and the average value is subtracted from each of the calculation results having been subjected to the phase conversion, to obtain only asynchronous angular errors.