Dual Scanner Head Gap Feedback for Stable Sheet Gauge Accuracy
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Solution Overview
Problem
Current scanning measurement systems for continuous sheet materials face challenges in maintaining a constant sensor gap, leading to inaccuracies in measurements due to variations in the distance between scanner heads, which affects radiation intensity and other sensor readings.
Innovation Solution
A closed-loop control system using actuators to maintain a constant sensor gap by measuring the gap distance and adjusting it in real-time, employing sensors like inductive-type, optical, or magnetic displacement sensors, and piezoelectric actuators to correct for positional errors and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scanning measurement systems are used to measure sheet properties, then on-line monitoring capability is improved, but measurement precision deteriorates due to sensor gap variations
Solution Approach 1:
The patent implements a feedback control system where displacement sensors continuously measure the actual sensor gap distance, and this measurement is fed back to a control system that adjusts the scanner head position to maintain the desired gap distance, thereby resolving the measurement precision deterioration caused by gap variations
Solution Approach 2:
The patent replaces mechanical gap adjustment mechanisms with piezoelectric actuators that can dynamically and precisely adjust the scanner head position based on electrical signals, enabling real-time compensation for gap variations without complex mechanical linkages
2Device complexity
If the sensor gap is allowed to vary during scanning, then device complexity is reduced, but measurement precision deteriorates due to radiation intensity variations
Solution Approach 1:
The system uses displacement sensors to continuously monitor the sensor gap and feeds this information back to a control system that adjusts the scanner head position, maintaining constant gap distance and thus constant radiation intensity for accurate measurements without requiring complex mechanical gap control mechanisms
Solution Approach 2:
The patent makes the scanner head position dynamic and adjustable during operation using piezoelectric actuators, allowing the system to adapt to varying conditions and maintain optimal measurement conditions rather than relying on a fixed, simple mechanical structure
3Measurement precision
If closed-loop control with actuators is implemented to maintain constant sensor gap, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical gap control mechanisms with piezoelectric actuators driven by electrical feedback signals, achieving precise sensor gap control through electrical rather than mechanical means, thereby improving measurement precision while keeping the added complexity manageable through electronic control
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 solution ensures accurate and consistent measurements by maintaining a stable sensor gap, reducing errors caused by misalignment and vibrations, and improving the precision of properties like basis weight and air weight measurements.
Implementation Method 1
employing sensors like inductive-type, optical, or magnetic displacement sensors
Implementation Method 2
employing sensors like inductive-type, optical, or magnetic displacement sensors
Implementation Method 3
employing sensors like inductive-type, optical, or magnetic displacement sensors
Implementation Method 4
employing sensors like inductive-type, optical, or magnetic displacement sensors, and piezoelectric actuators to correct for positional errors and vibrations
Implementation Method 5
an upper housing may carry a radiation source, such as a nuclear beta source, and a lower housing may carry a detector. In this case, the sensors can be employed to make basis weight measurements by measuring the radiation intensity incident on the detector when a sheet is present as compared to the beta radiation which is incident upon the detector, when no sheet is present; that is, the basis weight is measured by the beta radiation attenuated by the sheet material
Data Source
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AI summary
Sensors used in sheet manufacturing environments can be sensitive to the gap between the scanner heads. Nuclear gauges measure both the sheet product and gas in the column between the scanner heads. The gap distance can affect the measurement in a linear or non-linear fashion depending on the sensing principle. High frequency vibrations can cause the sensor devices therein to move. Techniques for controlling the sensor gap between operative surfaces on dual scanner heads during measurement operation employs a closed-loop control where piezoelectric actuators are used to maintain a constant gap throughout the scan by closing the error signal on the gap measurement sensor. A system for measuring a property of a continuous sheet includes dual scanner heads housing radiation emitters and receivers. Gap measurement signals energize the actuators that adjust the position of one or both sensor devices to maintain the gap at a desired distance.