Position Sensor Fine Position Determination Using Signal Averaging
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Solution Overview
Problem
Existing position sensors face challenges in achieving high accuracy and dynamic fine positioning due to influences from the geometry of the exciter field, sensor arrangement, and multiplicative and additive disturbance variables, which complicates the measurement process and requires laborious calibration procedures.
Innovation Solution
The method involves using multiple sensor signals, up to 16, to correlate amplitude values with fine position values without assuming sinusoidal or cosinusoidal curve shapes, employing averaging to eliminate noise, and storing genuine reference values for each position to enable accurate fine position determination without the need for complex calibration procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional position sensing methods are used, then position measurement can be achieved, but measurement precision deteriorates due to influences from exciter field geometry, sensor arrangement, and disturbance variables
Solution Approach 1:
The patent replaces traditional mechanical/calibration-based position sensing with a signal processing approach. Instead of physically adjusting and calibrating sensor positions to compensate for geometric influences, the invention uses mathematical evaluation of sensor signals to eliminate the effects of exciter field geometry and sensor arrangement variations, thereby achieving high measurement precision without complex calibration procedures
Solution Approach 2:
The patent changes the approach from fixed physical parameters (sensor positions, exciter geometry) to variable signal processing parameters. By evaluating amplitude values and their changes over time, and by using differential measurements, the system adapts to different geometric configurations without requiring physical reconfiguration or calibration, thus improving measurement precision while reducing calibration complexity
2Measurement precision
If multiple sensor signals are processed without averaging, then dynamic response is improved, but measurement precision deteriorates due to noise
Solution Approach 1:
The patent applies periodic sampling and averaging of sensor signals at optimized intervals. By periodically evaluating amplitude values and using moving averages, the system reduces noise while maintaining dynamic response capability. The periodic nature of the evaluation allows the system to track position changes effectively while filtering out high-frequency noise through the averaging process
3Measurement precision
If sinusoidal or cosinusoidal curve shape assumptions are made, then calculation complexity is reduced, but measurement precision deteriorates due to geometric influences
Solution Approach 1:
The patent replaces the assumption-based mathematical model with a model-free signal processing approach. Instead of assuming sinusoidal or cosinusoidal curve shapes and trying to fit data to these models, the invention directly evaluates amplitude values and their changes, using the actual measured signal characteristics without imposing theoretical curve shape constraints, thereby achieving higher precision while managing computational complexity through efficient algorithms
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 allows for highly accurate and dynamic fine positioning with reduced technical complexity and cost, as it eliminates the influence of disturbance variables and simplifies the calibration process, enabling high reproducibility and accuracy in position sensing.
Implementation Method 1
a stationary sensor unit serves for that counting operation and for fine resolution of the measuring segments, the sensor unit including at least two sensors formed for example by Hall elements
Data Source
AI summary
A position sensor for ascertaining the fine position value z of a movable body includes an exciter unit moving therewith and a stationary sensor unit (7) which simultaneously delivers a plurality of output signals jointly describing the fine position value. In a calibration mode there is established a defined relationship between the exciter unit and a calibration unit (31) such that groups of amplitude values can be taken off from said output signals and groups of average values are formed therefrom, which are fed to the calibration unit (31) which converts them into reference values using the calibration fine position values μ(z) and stores same with the associated fine position as an associated values multiplet in a comparative value memory (14). In each measuring mode groups of amplitude are taken off from the output signals from which groups of measuring values are produced by averaging and are fed to a computing unit (10), which forms differences of cross products from the reference values of varying groups of reference values and the current measuring value group and causes said differences to go towards zero to ascertain the current fine position value.