Wiegand Position Sensor with Magnetic Memory for Direction Ambiguity
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Solution Overview
Problem
Magnetic absolute position sensors face challenges in reliably determining the absolute position of a permanent magnet after a power disruption, particularly when the sensor is unable to recognize voltage impulses due to changes in movement direction, leading to ambiguity about the magnet's path to its current posture, which complicates synchronization and operation resumption upon re-establishing energy supply.
Innovation Solution
The proposed solution involves a position sensor with a Wiegand module, a magnetic temporary storage, and a processing electronic circuit that evaluates output signals from sensor elements to determine the number of repeating courses and precise posture of an object, using a Wiegand wire with a coil and a permanent magnet arrangement to generate voltage impulses based on magnetic field changes, allowing for direction and pole information determination, and utilizing a magnetic temporary storage to store information about the last passing pole for error-free synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the sensor uses a Wiegand module to generate voltage impulses for counting revolutions, then the sensor can operate autonomously without external energy supply, but the sensor cannot reliably determine the absolute position after a change in movement direction due to unrecognized voltage impulses
Solution Approach 1:
The patent applies preliminary action by storing the polarity information of the last recognized voltage impulse in a magnetic memory element before any ambiguity can occur. This stored polarity information serves as a reference that allows the sensor to correctly interpret subsequent voltage impulses and determine the absolute position even after direction changes, without requiring external energy supply.
Solution Approach 2:
The patent introduces a magnetic memory element as an intermediary that stores the polarity information of the last voltage impulse. This intermediary component bridges the gap between the Wiegand module's voltage impulse generation and the evaluation circuit's position determination, enabling reliable operation after direction changes by providing reference information about the previous state.
2Reliability
If the sensor waits for the next voltage impulse to resolve ambiguity about the magnet's path, then synchronization can be achieved, but the sensor cannot determine position when the magnet is stationary in an unfavorable angular range
Solution Approach 1:
The patent resolves this contradiction by performing preliminary action - storing the polarity information of the last voltage impulse in a magnetic memory element before any ambiguity occurs. This allows the evaluation circuit to immediately determine the absolute position upon receiving each voltage impulse by comparing its polarity with the stored reference, without needing to wait for additional impulses or move the magnet to resolve ambiguity.
3Loss of information
If the sensor uses a magnetic sensor to detect the magnetization direction of the Wiegand wire, then information about the movement path can be obtained, but the magnetic sensor requires very high precision due to the small remanence of the Wiegand wire
Solution Approach 1:
The patent replaces the requirement for a high-precision magnetic sensor with a simple magnetic memory element that stores polarity information. Instead of continuously measuring the weak magnetic field of the Wiegand wire, the system uses the magnetic memory element to retain polarity information, effectively replacing a complex, high-precision measurement function with a simpler information storage function.
4Loss of information
If the sensor supplies current to the coil to reverse magnetism of the Wiegand wire for path evaluation, then movement path information can be obtained, but additional component parts and costs are incurred
Solution Approach 1:
The patent extracts only the essential information needed for position determination - the polarity of the last voltage impulse - and stores it in a simple magnetic memory element. This eliminates the need for complex active testing methods involving current supply to the coil, while still providing sufficient information for accurate position determination and synchronization.
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 approach enables efficient and reliable synchronization of the position sensor, allowing it to determine the absolute position of the permanent magnet even without external energy, by using the stored information to resolve ambiguity and ensure accurate counting and posture determination upon re-establishing power.
Implementation Method 1
a Wiegand module, which is composed of a Wiegand wire and has a coil which surrounds the Wiegand wire; upon movement of the permanent magnet arrangement in said one direction, the coil of the Wiegand module generates a voltage impulse
Implementation Method 2
a magnetic temporary storage to store information about the last passing pole for error-free synchronization
Data Source
AI summary
A position sensor is disclosed for determining the number of repeating courses of movement of an object and of the precise position of the object in relation to a reference position. The position sensor is disclosed to include a Wiegand module, which is composed of a Wiegand wire having a coil that surrounds the Wiegand wire; a magnetic temporary storage, which is in addition to the Wiegand module; a first sensor element and a second sensor element; a processing electronic circuit, which is configured to evaluate or to determine an output signal that is output by the sensor elements and an information that is stored in the magnetic temporary storage; and a permanent magnet arrangement, which is movable relatively to the Wiegand module in one direction as well as in a direction that is opposite to said one direction.