Heating Control Using Transfer Functions for Sensor Fault Detection
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Solution Overview
Problem
Existing heating devices with temperature sensors and heaters face challenges in accurately detecting temperature abnormalities, leading to incorrect temperature control of heating objects.
Innovation Solution
A heating device equipped with multiple temperature sensors and a temperature regulator that identifies heat transfer functions and detects changes in coefficients to determine abnormalities in the heater or temperature sensors, using a determination unit to set thresholds for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single temperature sensor is used to detect heating object temperature, then the device structure is simple, but the reliability of temperature detection is insufficient when abnormalities occur
Solution Approach 1:
The temperature detection function is segmented into multiple independent temperature sensors instead of using a single sensor. This segmentation allows the system to detect abnormalities in individual sensors and cross-validate temperature readings, thereby improving detection reliability while managing complexity through modular sensor units.
Solution Approach 2:
The system performs preliminary identification of heat transfer functions between the heater and each temperature sensor before actual heating operations. This preliminary characterization enables the abnormality detection unit to compare actual sensor readings against expected thermal behavior, allowing early detection of sensor or heater abnormalities before they affect product quality.
2Measurement precision
If multiple temperature sensors are added to improve detection reliability, then temperature abnormality detection capability is enhanced, but the device complexity increases
Solution Approach 1:
The system implements feedback control by continuously comparing temperature sensor readings against the identified heat transfer functions and detecting deviations that indicate abnormalities. The abnormality detection unit provides feedback about sensor and heater status, enabling the system to maintain measurement precision while managing complexity through intelligent monitoring rather than simply adding more sensors.
Solution Approach 2:
The patent replaces purely mechanical/additional sensor approaches with a computational solution that uses identified heat transfer functions and abnormality detection algorithms. This substitution of physical complexity with computational intelligence allows the system to achieve high measurement precision for abnormality detection without proportionally increasing device complexity.
3Reliability
If heat transfer functions are identified and coefficients are monitored for abnormality detection, then the accuracy of determining heater or sensor abnormalities is improved, but the processing complexity and time increase
Solution Approach 1:
The heat transfer functions between the heater and temperature sensors are identified in advance during an initialization phase before actual heating operations begin. This preliminary identification stores the thermal characteristics of the system, allowing rapid abnormality detection during operation without requiring real-time complex calculations, thus improving determination accuracy while minimizing time loss during production.
4Measurement precision
If thresholds are set based on ratios to initial coefficient values, then the accuracy of abnormality detection is improved across different coefficients, but the complexity of threshold configuration increases
Solution Approach 1:
The system uses parameter changes by setting thresholds as ratios relative to the initial coefficient values of the heat transfer functions. This approach normalizes the threshold configuration across different coefficients and operating conditions, improving detection precision while reducing configuration complexity through a unified ratio-based methodology rather than requiring separate absolute threshold values for each parameter.
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 enables reliable detection of temperature abnormalities, preventing defective product molding in machines like injection and extrusion molding machines by ensuring accurate temperature control.
Implementation Method 1
a heater (10) that heats a heating object (1)
Implementation Method 2
a temperature detection unit (20) that detects a temperature of the heating object (1)
Data Source
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AI summary
This heating device (100) includes: a heater (10) for heating an object (1) to be heated; a temperature detection unit (20) for detecting a temperature of the object (1) to be heated; and a temperature regulator (30) which, on the basis of a detection value of the temperature detection unit (20) and a target temperature, controls the heater (10) so as to make the temperature of the object (1) to be heated equal to the target temperature. The temperature detection unit (20) comprises a plurality of temperature sensors (21, 22). An identification unit (34) identifies, from temperature data detected by the temperature sensors (21, 22) and manipulation quantity data corresponding to electric power applied to the heater (10), a heat transfer function between the heater (10) and the temperature sensors (21, 22), and a heat transfer function between the respective temperature sensors (21, 22). A determination unit (36) detects a change from initial values of coefficients of the transfer functions, and, on the basis of that change, determines an abnormality in the heater (10) or the temperature sensors (21, 22).