Absolute Position Readout Apparatus Using Offset Magnetic Sensors
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Solution Overview
Problem
Conventional absolute position readout apparatuses experience misreading of absolute position information due to weak magnetic fields sensed by digital Hall sensors at absolute-track boundaries, leading to incorrect alignment with either adjacent magnetized regions.
Innovation Solution
The apparatus includes an encoder device with absolute and incremental magnetic tracks, and a readout device with specific magnetic sensing components arranged to sense magnetic fields within predetermined ranges, allowing for correct decoding of absolute position information by selecting appropriate sensed magnetic fields based on relative positional relationships between sensing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If digital Hall sensors are aligned with absolute-track boundaries for position sensing, then the sensing arrangement is simplified, but the magnetic field strength becomes too weak causing misreading of absolute position information
Solution Approach 1:
The patent introduces an offset alignment between the digital Hall sensors and the absolute-track boundaries, where the sensors are deliberately positioned at a predetermined distance (offset) from the boundaries rather than being directly aligned with them. This preliminary positioning prevents the sensors from operating in the weak magnetic field regions at the boundaries, thereby avoiding misreading while maintaining a simple sensing arrangement.
2Measurement precision
If multiple types of magnetic sensing components are used to improve measurement accuracy, then the reading accuracy improves, but the device complexity increases
Solution Approach 1:
The patent employs multiple types of magnetic sensing components (digital Hall sensors, analog Hall sensors, and magnetoresistive sensors) that serve different functions within the same position readout system. Each sensor type is optimized for specific measurement tasks - digital Hall sensors for absolute position, analog Hall sensors for incremental position, and magnetoresistive sensors for high-precision measurements - allowing the system to achieve high accuracy without requiring completely separate sensing systems for different measurement needs.
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
Prevents misreading of absolute position information by accurately determining the position of absolute-track magnetized regions, even when magnetic fields are weak, ensuring precise alignment and correct readout.
Implementation Method 1
The digital Hall sensors 121 are configured to sense magnetic fields of the absolute-track magnetized regions 113 that correspond in position thereto
Implementation Method 2
The magnetoresistive sensor 122 is configured to sense movement amount of the first incremental-track magnetized regions 116 and the second incremental-track magnetized regions 117 by magnetic sensing
Data Source
AI summary
An absolute position readout apparatus includes an encoder device and a readout device. The readout device includes multiple first and second magnetic sensing components that correspond to an absolute track of the encoder device, and a third magnetic sensing component and a fourth magnetic sensing components that correspond to an incremental track of the encoder device. The third magnetic sensing component is configured to be spaced apart from the fourth magnetic sensing component by a specific distance, so as to prevent misreading of absolute position information from the first or second magnetic sensing components being at positions corresponding to boundaries between adjacent magnetized regions of the absolute track.