Angle Detector Sensor Arrangement for Error Compensation
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Solution Overview
Problem
Existing angle detectors face challenges in accurately measuring angle changes due to electrical and mechanical errors caused by sensor characteristics, graduation quality, and attachment accuracy, which are not uniformly removable and can lead to increased costs when using high-accuracy sensors.
Innovation Solution
An angle detector design with multiple sensors positioned along the circumference of a rotary body, where the number of sensors is determined based on the remainder of dividing the order of the electrical angle error by the integer number of planned sensor locations, allowing for the removal of both electrical and mechanical angle errors, enabling accurate angle change measurement without the need for high-cost sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of sensors is increased to remove more harmonic component distortions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the measurement task into multiple independent sensor channels, each reading from different positions on the scale. By segmenting the measurement function across multiple sensors with different phases, the system can process and cancel harmonic distortions through signal combination, achieving high precision without requiring a single overly complex sensor
Solution Approach 2:
The patent introduces the dimension of spatial arrangement by positioning sensors at different angular positions around the rotary body. This dimensional approach allows the system to capture multiple phase information simultaneously, enabling harmonic distortion removal through mathematical processing of multi-dimensional signal data
2Measurement precision
If high-accuracy sensors are used to reduce electrical angle errors, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent employs multiple relatively inexpensive sensors instead of a single high-precision sensor. By using multiple lower-cost sensing elements that can be easily replaced or manufactured, the system achieves high measurement accuracy through signal processing rather than relying on expensive individual sensor components
Solution Approach 2:
The patent combines the output signals from multiple sensors through mathematical processing to achieve high measurement accuracy. By merging the information from multiple lower-precision sensors, the system attains the precision equivalent to or better than a single high-precision sensor, thereby reducing overall cost
3Measurement precision
If the axial offset between rotary axis and scale center axis is reduced to eliminate mechanical angle errors, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses the output signals from multiple sensors arranged at different positions to detect and compensate for axial offset errors. By analyzing the phase differences and amplitude variations in the sensor signals, the system can identify mechanical alignment errors and apply correction algorithms to eliminate their effect on measurement accuracy
Solution Approach 2:
The patent performs error compensation through signal processing before final angle calculation. By preliminarily processing the sensor signals to remove harmonic distortions and mechanical errors, the system prepares corrected data that eliminates the need for extremely precise mechanical alignment during manufacturing and assembly
Data Source
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AI summary
The present invention provides an angle detector for detecting an amount of angular change due to the rotation of a rotary body. The angle detector 101 is provided with: a rotary body 105 rotating around a rotation axis; a graduated scale 102 having a plurality of graduations 103 along the circumference of the rotary body in the rotation direction; and a plurality of sensors 201a, 201b disposed along the circumference. Each of the sensors 201a, 201b outputs a signal according to an amount of angular change on the basis of the plurality of graduations 103. The output signal includes: a fundamental wave component having one of the plurality of graduations as the first period first order; and a harmonic wave component having an order that is an integer multiple of at least two times the fundamental wave component. An amount of angular displacement calculated from the output signal includes an angular error component that is due to the harmonic wave component and has an order component that is an integer multiple of the one graduation that is the first period first order. The number of the plurality of sensors 201a, 201b is determined on the basis of the number of graduations on the graduated scale and the order component of the angular error component.