Magnetic Position Sensor Calibration for Linearity Error Compensation
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Solution Overview
Problem
Conventional magnetic position sensors in pneumatic or hydraulic drives suffer from linearity errors, which limit their accuracy in distinguishing between objects with slight size differences or position variations, requiring costly path measuring systems for improved precision.
Innovation Solution
A method for calibrating magnetic position sensors by approaching multiple calibration positions, determining position differences, and compensating for linearity errors, allowing for simple and inexpensive linearization of the sensor and drive system, with the option for repeated calibration at different temperatures and using a calibration piece with spacer structures to simplify the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic position sensors are used without calibration, then the device complexity remains low, but the measurement precision deteriorates due to linearity errors
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements at multiple predetermined positions before actual operation. The control unit stores reference values obtained during manufacturing or initial calibration, which are then used to compensate for linearity errors during normal operation, eliminating the need for complex real-time correction systems.
Solution Approach 2:
The magnetic position sensor performs self-calibration through the control unit, which automatically compares measured positions with stored reference values and applies compensation. This self-service approach eliminates the need for external complex calibration equipment or manual intervention during operation.
2Measurement precision
If expensive path measuring systems are used to improve accuracy, then the measurement precision improves, but the cost increases significantly
Solution Approach 1:
The patent uses a simple calibration piece with predetermined positions that can be easily manufactured and replaced if needed. This inexpensive calibration aid enables accurate measurements without requiring expensive permanent path measuring systems, achieving high precision through a low-cost, simple calibration process.
3Measurement precision
If manual linearization is performed in a superordinate controller, then the measurement precision improves, but the ease of operation deteriorates due to complex manual procedures
Solution Approach 1:
The control unit integrated with the magnetic position sensor automatically performs linearization by comparing measured positions with stored reference values and applying compensation algorithms. This eliminates the need for complex manual linearization procedures in external controllers, making the system easier to operate while maintaining high precision.
Solution Approach 2:
The patent merges the calibration and linearization functions into the control unit that is already integrated with the magnetic position sensor. This consolidation eliminates the need for separate manual linearization steps in external controllers, simplifying operation while achieving accurate linearity correction.
4Measurement precision
If calibration is performed at multiple temperatures, then the measurement precision improves across different operating conditions, but the time required for calibration increases
Solution Approach 1:
The patent performs comprehensive multi-temperature calibration measurements during the manufacturing process or initial setup, storing reference values for different temperature conditions. This preliminary action ensures that the sensor is pre-adapted to various operating temperatures, eliminating the need for time-consuming recalibration during actual operation while maintaining high precision across temperature ranges.
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
Significantly improves linear behavior and reduces position errors, enabling precise position determination without complex manual linearization, and allows for sensor- and drive-specific adjustments in the assembled state, reducing costs and enhancing accuracy.
Implementation Method 1
a magnet and a magnetic sensor, which change their linear position relative to one another when the sliding element moves, with the influence of its magnetic field, which changes with position, is measured
Data Source
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AI summary
A method for calibrating a magnetic position sensor (10) is described, which determines the position of a linearly movable sliding element (12) relative to a housing (16) of the magnetic position sensor (10). The sliding element (12) is successively moved to several known calibration positions, the position measured there by the magnetic position sensor (10) is compared with the known calibration position, and a position difference is determined, which is compensated for in future measurements.