Rotation Sensor Signal Processing for Noise Suppression
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Solution Overview
Problem
Conventional rotation sensors using hysteresis comparator circuits face accuracy issues due to noise interference and reduced pulse numbers, leading to inadequate control of rotator states, especially when dealing with rotators having a small number of projections or periodic magnetic flux variations.
Innovation Solution
A rotation sensor design that employs a magnetoelectric conversion unit producing two detection signals with the same period but different phases, processed by comparison units to generate and adjust detection thresholds, resulting in pulse signals with increased accuracy and doubled pulse numbers by ensuring pulse rising and falling edges occur at consistent voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hysteresis comparator circuit with two thresholds is used to suppress noise interference, then the reliability of pulse signal generation is improved, but the measurement precision of rotation state decreases due to threshold voltage level differences
Solution Approach 1:
The detection signal is segmented into two separate detection signals with different phases. Each detection signal is processed independently through its own comparison unit, allowing the system to maintain single-threshold precision while still achieving noise suppression through the phase difference between the two signals.
Solution Approach 2:
A phase difference is introduced as an intermediary mechanism between the two detection signals. This phase difference allows the system to distinguish between valid signal transitions and noise interference, enabling accurate rotation state detection while maintaining reliability.
2Reliability
If the pulse falling edge is generated when the input signal falls below a lower second threshold, then noise suppression is improved, but the number of pulses in the pulse signal decreases for rotators with small number of projections
Solution Approach 1:
The pulse generation process is segmented into two independent pathways, each generating pulses based on a single threshold. This segmentation ensures that the number of pulses corresponds accurately to the number of projections on the rotator, while the phase difference between the two detection signals provides the noise suppression mechanism.
3Measurement precision
If a single threshold is used for pulse rising and falling edges to maintain accuracy, then the measurement precision is improved, but the reliability decreases due to susceptibility to noise interference
Solution Approach 1:
The single threshold comparison is segmented into two separate comparison processes, each handling one detection signal. The phase difference between the detection signals creates a temporal separation that allows the system to distinguish valid transitions from noise, maintaining both precision and reliability.
Solution Approach 2:
The periodic nature of the two detection signals with different phases is utilized to create a rhythm in the pulse generation process. This periodic action with phase difference allows the system to identify valid signal patterns versus random noise, improving reliability without sacrificing precision.
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 enhances the accuracy of pulse signals and increases the number of pulses, effectively improving the control of rotator states by mitigating noise interference and maintaining consistent threshold voltage levels.
Implementation Method 1
a magnetoelectric conversion unit that converts change of magnetic flux whose direction changes periodically into an electric signal
Data Source
AI summary
A rotation sensor has a magnetoelectric conversion unit that converts change of magnetic flux whose direction changes periodically with rotation of a rotator into an electric signal and a processing unit that processes the electric signal. The magnetoelectric conversion unit outputs a first detection signal and a second detection signal. The processing unit has a first comparison unit that compares a detection threshold and the first detection signal and a second comparison unit that compares a reference threshold and the second detection signal. The first comparison unit changes a voltage level of the detection threshold when the first detection signal exceeds or falls below the detection threshold and then restores the voltage level of the detection threshold based on the second detection signal and the reference threshold, and the first comparison unit converts the first detection signal into a pulse signal based on the detection threshold of the same voltage level.