Movement Detection Unit Using Dual Sensors for Low-Speed Rotation
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Solution Overview
Problem
Existing rotation detection units face challenges in accurately detecting low-speed gear wheel rotations due to limited teeth count and interference between adjacent teeth, which reduces magnetic field changes and detection sensitivity.
Innovation Solution
A movement detection unit comprising a movable body, first and second sensors, and a signal processor with a signal generating circuit that generates signals with different waveforms, allowing for the detection of small rotations by producing pulses at different timings through comparisons between these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of teeth in a gear wheel is increased to detect small rotations, then the detection precision of low-speed movement is improved, but the magnetic field changes around the gear teeth become smaller and adjacent gear teeth magnetic fields interfere with each other
Solution Approach 1:
The patent divides the detection function into multiple sensors (first sensor and second sensor) positioned at different locations. Each sensor detects magnetic field changes from different gear teeth, and the signal processing unit combines these segmented detections to achieve high-precision measurement without requiring excessive teeth density that would cause magnetic interference
Solution Approach 2:
The signal processing unit acts as an intermediary that receives signals from multiple sensors and processes them to generate detection results. This intermediary processing allows the system to achieve high detection precision through signal combination and analysis rather than relying solely on increasing the number of gear teeth, thereby avoiding magnetic field interference issues
2Measurement precision
If the dimensions of gear teeth are reduced to increase the number of teeth, then the number of detectable teeth increases, but the magnetic field changes around the gear teeth become smaller
Solution Approach 1:
The patent transitions from relying solely on the dimensional parameter of gear teeth size to utilizing the spatial dimension by positioning multiple sensors at different locations. This dimensional approach allows detection of magnetic field changes from multiple teeth simultaneously, achieving high precision without requiring individually large teeth that would generate strong but interfering magnetic fields
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
This configuration enables high-precision detection of low-speed movements by increasing the number of pulses, thereby improving the accuracy of rotation speed and angle determination.
Implementation Method 1
The first sensor detects a first magnetic field change which is caused by the movement of the movable body
Implementation Method 2
The second sensor detects a second magnetic field change which is caused by the movement of the movable body
Data Source
AI summary
A movement detection unit includes a movable body, a first sensor, a second sensor, and a signal processor. The movable body performs a movement in a first direction. The first sensor detects a first magnetic field change which is caused by the movement of the movable body and outputs a first signal. The second sensor is provided in the first direction at a location different from a location of the first sensor. The second sensor detects a second magnetic field change which is caused by the movement of the movable body and outputting a second signal. The signal processor includes a signal generating circuit that generates a third signal and a fourth signal on a basis of the first signal. The third signal and the fourth signal have waveforms different from each other.