Load Cell Compensation Using Reference Sensor
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Solution Overview
Problem
Traditional inventory management systems using load cells face challenges in accurately determining weight due to factors like temperature, humidity, and aging, which can lead to overstock or stockout situations, and require costly calibration and zeroing processes.
Innovation Solution
The use of loaded weight sensors and reference weight sensors, which are subjected to the same environmental factors, allows for real-time compensation of weight data by subtracting variance from the reference sensor's output, eliminating the need for zeroing and specialized calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional load cells are used for weight measurement, then the system can determine inventory weight, but temperature, humidity, and aging factors cause measurement drift requiring costly calibration and zeroing processes
Solution Approach 1:
The patent creates a reference copy of the load cell that experiences identical environmental conditions (temperature, humidity, aging) but does not bear the platform weight. This reference load cell copies the environmental drift effects, allowing the system to subtract these effects from the main measurement without requiring periodic calibration or zeroing operations.
Solution Approach 2:
The reference load cell acts as an intermediary that mediates between the environmental factors and the main load cell measurement. By measuring the drift through the reference load cell and using it to compensate the main measurement, the system eliminates the need for direct calibration interventions while maintaining measurement accuracy.
2Measurement precision
If traditional load cells are used for weight measurement, then the system can monitor inventory, but environmental factors cause drift requiring costly calibration processes
Solution Approach 1:
The patent creates a reference copy of the load cell that experiences identical environmental conditions (temperature, humidity, aging) but does not bear the platform weight. This reference load cell copies the environmental drift effects, allowing the system to subtract these effects from the main measurement without requiring periodic calibration or zeroing operations.
Solution Approach 2:
The system performs self-compensation by using the reference load cell to automatically track and correct for environmental drift. The microcontroller continuously monitors the reference load cell output and applies compensation to the main measurement in real-time, eliminating the need for external calibration services or manual zeroing operations.
3Measurement precision
If reference weight sensors are added to the system, then environmental compensation improves measurement accuracy, but device complexity increases
Solution Approach 1:
The patent segments the measurement function into two independent parts: the main load cell that measures total weight (platform + inventory) and the reference load cell that measures only environmental drift. This segmentation allows each component to have a specialized function, simplifying the overall system architecture despite adding another sensor.
Solution Approach 2:
The patent merges the reference load cell measurements with the main load cell measurements through digital signal processing in the microcontroller. By combining these measurements and subtracting the reference drift from the main measurement, the system achieves compensation while maintaining a unified measurement output that masks the underlying complexity.
4Reliability
If loaded and reference weight sensors are used simultaneously, then real-time compensation is achieved, but the quantity of sensors and device complexity increase
Solution Approach 1:
The patent implements continuous compensation by having both the main load cell and reference load cell operate simultaneously and continuously. The microcontroller continuously reads both sensors and applies real-time compensation calculations, ensuring that environmental drift is corrected at all times rather than through periodic calibration cycles.
Solution Approach 2:
The patent creates a reference copy of the load cell that experiences identical environmental conditions (temperature, humidity, aging) but does not bear the platform weight. This reference load cell copies the environmental drift effects, allowing the system to subtract these effects from the main measurement without requiring periodic calibration or zeroing operations.
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 provides accurate and reliable weight data for inventory management, reducing production and ongoing costs, and enabling extended operation without zeroing, while improving the accuracy of inventory levels and reducing the risk of apparatus failure detection.
Implementation Method 1
load cells, which may change electrical resistance in response to applied force
Data Source
AI summary
An apparatus includes a platform that is supported by a first set of load cells. Output from these load cells may be adversely influenced by factors such as temperature, humidity, aging, and so forth. The device includes a second set of load cells that are unloaded, that is they do not support the platform. Output from the first set of load cells is digitized to produce first digital data while output from the second set of load cells is digitized to produce second digital data. The first digital data and the second digital data are processed to produce compensated data. For example, values of the second digital data may be subtracted from values of the first digital data to produce the compensated data. In other implementations, other processing may be used. The resulting compensated data may be used to provide highly accurate weight data about the platform.