Closed Loop Magnetic Field Control for Head Testing
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Solution Overview
Problem
Existing magnetic head testers struggle to accurately control and maintain the desired magnetic field during testing, often requiring precise positioning of the magnetic field sensor at an equipotential location with the head, which can be restrictive and inefficient, especially when testing multiple heads or in crowded conditions.
Innovation Solution
A magnetic recording head tester employing closed-loop control with a magnetic field sensor positioned at a different location than the head, using calibration to correlate the sensor's output signal with the magnetic field magnitude at the head, allowing for precise adjustment and maintenance of the desired magnetic field through a feedback loop and software control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic field sensor is positioned at an equipotential location with the head to ensure accurate field sensing, then measurement precision is improved, but device complexity and ease of operation deteriorate due to restrictive positioning requirements
Solution Approach 1:
The patent introduces a magnetic field sensor as an intermediary device positioned at a convenient location rather than at the equipotential position. The sensor measures the magnetic field at its location, and through calibration and calculation, the magnetic field at the head's location is determined. This mediator approach allows the sensor to be placed where it is easily accessible while still providing accurate information about the field at the head.
Solution Approach 2:
The patent replaces the mechanical requirement of positioning the sensor at an equipotential location with a computational approach. Instead of mechanically constraining the sensor to a specific position, the system uses software calculations and calibration data to determine the magnetic field at the head based on measurements from any sensor location. This substitution of mechanical positioning requirements with computational methods improves ease of operation.
2Measurement precision
If the magnetic field sensor is positioned at an equipotential location with the head to ensure accurate field sensing, then measurement precision is improved, but device complexity increases due to restrictive positioning and system design
Solution Approach 1:
The magnetic field sensor serves as an intermediary that measures the field at a convenient location. The system then uses calibration data and computational algorithms to translate this measurement into an accurate representation of the field at the head. This intermediary approach simplifies the overall system design by eliminating the need for complex equipotential positioning mechanisms.
Solution Approach 2:
The patent changes the parameter of sensor location from a fixed equipotential position to a variable convenient position. Through calibration, the system establishes a relationship between the magnetic field at the sensor location and the magnetic field at the head location. This parameter change allows the sensor to be positioned anywhere, reducing the complexity of positioning mechanisms while maintaining measurement accuracy through computational correction.
3Manufacturing precision
If closed loop control is implemented to accurately control the magnetic field, then manufacturing precision is improved, but device complexity increases due to feedback loop requirements
Solution Approach 1:
The patent implements closed-loop control by continuously measuring the magnetic field using the sensor, comparing the measured value with the desired value, and adjusting the magnetic field generation accordingly. This feedback mechanism ensures that the magnetic field at the head location is maintained at the desired level, improving manufacturing precision. The feedback loop uses the sensor positioned at a convenient location with calibration data to control the field at the head, managing complexity through computational methods.
Solution Approach 2:
The patent replaces complex mechanical field adjustment mechanisms with a control system that uses software and calibration data. Instead of requiring precise mechanical positioning and adjustment mechanisms, the system uses computational algorithms to calculate the necessary adjustments based on sensor readings and calibration data, thereby reducing mechanical complexity while maintaining or improving control accuracy.
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
Enables accurate and efficient control of the magnetic field at the head, allowing for precise testing and increased throughput by decoupling the sensor's location from the head's location, overcoming limitations of conventional systems that require equipotential positioning and simplifying system design and calibration.
Implementation Method 1
A magnetic field sensor 110 is positioned so that it can detect the magnetic field produced by the magnetic field generation device 102
Implementation Method 2
a magnetic field generation device 102, which may be an electromagnet with a high permeability magnetic core that includes a gap 103 between two poles 102a and 102b
Data Source
AI summary
A magnetic recording head tester uses closed loop control to accurately control the magnetic field that is generated to test the magnetic recording head. The closed loop control compares the value of the sensed magnetic field to the desired value of the magnetic field and adjusts the magnetic field accordingly. A magnetic field sensor used in the tester may be located in a position that has a substantially different magnetic field magnitude than is experienced by the magnetic recording head. The value of the output signal from the magnetic field sensor is correlated to the magnitude of the magnetic field at the location of the magnetic recording head through calibration. The correlation can then be used to accurately produce the desired magnitude magnetic field at the location of the magnetic recording head.