Weigh-in-motion Load Cell Segmentation for Moment Error Compensation
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Solution Overview
Problem
Current weigh-in-motion systems face challenges in achieving accurate weight measurements of moving vehicles due to moments and movements generated during the weighing process, which affect the accuracy and require significant time for stabilization, and they lack the ability to provide data on vehicle speed and loading irregularities.
Innovation Solution
A weigh-in-motion system utilizing multiple load cell assemblies at the leading and trailing edges of a platform, supported by a base, generates data for weight determination, identifies crossover points, and compares profiles to account for speed variations and loading irregularities, ensuring accurate and reliable weight measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load cells are positioned underneath the active section to measure compression force, then weight measurement capability is provided, but moments generated when tires pass over create measurement inaccuracies
Solution Approach 1:
The active section is divided into multiple segments with load cells positioned at specific locations (leading edge, trailing edge, and intermediate positions). This segmentation allows the system to capture moment effects at different points and calculate accurate axle weights by analyzing the distribution of forces across segments, thereby compensating for moment-induced errors.
Solution Approach 2:
The patent introduces intermediate load cells positioned between the leading and trailing edge load cells. These intermediate load cells act as mediators that capture the moment effects occurring during axle passage. By measuring forces at multiple intermediate points, the system can mathematically eliminate moment effects and derive accurate axle weights.
2Reliability
If the platform is designed to abut against a stop to arrest forward and downward movement, then measurement stability is improved, but the time required for stabilization increases
Solution Approach 1:
The patent positions load cells at the leading edge of the active section to detect axle approach and weight application before the axle fully settles. This preliminary detection allows the system to begin processing weight data earlier in the weighing process, reducing the time required to obtain accurate measurements while maintaining stability through continuous monitoring.
Solution Approach 2:
The system continuously monitors weight forces across multiple load cell positions throughout the entire axle passage. This continuous measurement approach eliminates the need for a stop mechanism, as the system can identify and lock onto the stable weight reading during the continuous data stream, thereby maintaining measurement stability without sacrificing time.
3Measurement precision
If multiple load cell assemblies are used at leading and trailing edges to account for speed variations, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The load cell assemblies at leading and trailing edges serve multiple functions: they measure axle weights, detect axle approach and departure, determine vehicle speed, and identify loading irregularities. This multi-functionality reduces the need for separate specialized components, thereby improving measurement accuracy without proportionally increasing system complexity.
Solution Approach 2:
The system uses the weight measurement data from the load cell assemblies to automatically determine vehicle speed and detect loading irregularities without requiring additional sensors or complex external systems. The same load cell data serves multiple purposes, allowing the system to self-service multiple measurement needs with a single component configuration.
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
The system provides enhanced accuracy and reliability in weight measurements, allows for the determination of vehicle speed, and identifies loading irregularities, reducing errors associated with moment-induced inaccuracies and stabilizing time, while enabling efficient data collection.
Implementation Method 1
Each load cell assembly generates respective data indicative of a load profile on the load cell assembly as a vehicle crosses the platform
Data Source
AI summary
A weigh-in-motion system includes a base, a load cell assembly supporting a leading edge of a platform structure movable with respect to the base, and a load cell assembly supporting a trailing edge of the platform. A processor is configured to execute program instructions in a memory to obtain load profile data generated by the load cells and to determine a weight associated with a vehicle using the load profile data. The processor is further configured to execute the program instructions to generate an output based upon the determined weight.