Magnet-Based Angle Sensing with Wiegand Interference Compensation
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Solution Overview
Problem
Existing angle-of-rotation sensor systems suffer from systematic errors due to interfering magnetic fields generated by Wiegand sensor units, affecting the accuracy of magnetic field sensor signals and resulting angle of rotation values.
Innovation Solution
A magnet-based angle-of-rotation sensor system with an excitation unit generating an alternating magnetic field, a Wiegand sensor unit producing voltage pulses, a magnetic field sensor unit detecting this field, and evaluation electronics applying compensation parameters to the magnetic field sensor signal to correct for interference effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the Wiegand sensor unit and magnetic field sensor unit are arranged at a small distance from each other, then the device complexity is reduced, but the measurement precision deteriorates due to interfering magnetic fields from Wiegand wire magnetization
Solution Approach 1:
The patent applies preliminary anti-action by introducing compensation parameters that pre-counteract the interfering magnetic field effects from the Wiegand wire. The evaluation electronics uses these parameters to compensate for the systematic errors before final angle calculation, effectively neutralizing the harmful magnetic interference in advance.
Solution Approach 2:
The patent introduces compensation parameters as an intermediary element between the magnetic field sensor unit and the angle of rotation calculation. These parameters act as a mediator that corrects the magnetic field sensor signal by accounting for the interfering fields, allowing accurate measurement despite the close proximity of sensor units.
2Device complexity
If the Wiegand sensor unit and magnetic field sensor unit are arranged at a small distance from each other, then the device structure is simplified, but the reliability deteriorates due to systematic errors in magnetic field detection
Solution Approach 1:
The patent implements feedback by using the known characteristics of Wiegand wire magnetization to generate compensation parameters that are fed back into the signal processing chain. The evaluation electronics continuously applies these compensation parameters to correct the magnetic field sensor signal, creating a feedback loop that maintains signal reliability despite the interfering fields.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing compensation parameters that account for the interfering magnetic fields before they affect the measurement. This preliminary preparation of correction data allows the system to reliably compensate for systematic errors during operation without adding complex real-time correction mechanisms.
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
Provides a reliable and accurate determination of shaft rotation by compensating for interference from Wiegand wires, enhancing the precision of angle-of-rotation measurements.
Implementation Method 1
the excitation unit is configured to be mounted so as to rotate with the shaft and to generate an alternating excitation magnetic field at the location of the Wiegand sensor unit and at the location of the magnetic field sensor unit when the shaft rotates
Implementation Method 2
the Wiegand sensor unit is configured so that Wiegand sensor voltage pulses are generated in the sensor coil by the alternating excitation magnetic field
Implementation Method 3
the magnetic field sensor unit is configured to detect the alternating excitation magnetic field and to provide a corresponding magnetic field sensor signal
Data Source
AI summary
A magnet-based angle-of-rotation sensor system for detecting a shaft's rotational movement includes an excitation unit having a magnet, a Wiegand sensor unit having a Wiegand wire arranged within a sensor coil, a sensor unit, and an evaluation electronics. The excitation unit rotates with the shaft and generates an alternating excitation magnetic field at the Wiegand sensor unit and at the sensor unit. The Wiegand sensor unit generates Wiegand sensor voltage pulses in the sensor coil via magnetic field. The sensor unit detects the magnetic field and provides a sensor signal. The evaluation electronics detects the Wiegand sensor voltage pulses and determines a number of revolutions based thereon, and receives the sensor signal and determines an angle of rotation value based thereon. The evaluation electronics alternately applies a first and a second compensation parameter to the received magnetic field sensor signal when determining the angle of rotation value.