Vehicle Weighing Scale Axle Detection via Load Sensor Unbalance Current
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Solution Overview
Problem
Conventional vehicle weighing systems face accuracy issues, particularly with short weighing bridges and long bridges where determining individual axle weights and total vehicle weight is challenging, especially when wheelbase matches the bridge length, and require additional complex components like tape switches, cameras, or radars, reducing robustness.
Innovation Solution
A weighing scale with a weighing bridge having load sensors on both sides, a measuring circuit to detect unbalance currents, and a processing circuit to determine the exact time wheels enter or leave the bridge, using existing load sensors and resistances or transformers to enhance accuracy without additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional systems use additional components such as tape switches, cameras, or radars to determine axle position and speed, then measurement precision of axle entry and exit points is improved, but device complexity increases and reliability decreases
Solution Approach 1:
The load sensors originally designed only for weight measurement are made to serve dual purposes: both weighing and detecting axle position. By analyzing the temporal pattern of weight signals from these existing sensors, the system determines when axles enter and exit the weighing bridge without requiring dedicated position detection components.
Solution Approach 2:
The weighing system uses its own weight measurement capability to also perform position detection. The load sensors and processing circuits inherently generate weight signals that contain positional information, which are extracted through signal analysis rather than requiring separate detection systems.
2Measurement precision
If conventional systems use additional components such as tape switches, cameras, or radars to determine axle position and speed, then measurement precision of axle entry and exit points is improved, but reliability decreases
Solution Approach 1:
The load sensors originally designed only for weight measurement are made to serve dual purposes: both weighing and detecting axle position. By analyzing the temporal pattern of weight signals from these existing sensors, the system determines when axles enter and exit the weighing bridge without requiring dedicated position detection components.
Solution Approach 2:
The weighing system uses its own weight measurement capability to also perform position detection. The load sensors and processing circuits inherently generate weight signals that contain positional information, which are extracted through signal analysis rather than requiring separate detection systems.
3Productivity
If a relatively long weighing bridge is used to enable weigh-in-motion, then productivity is improved, but difficulty of detecting and measuring axle weights increases when wheelbase matches bridge length
Solution Approach 1:
The weighing bridge is divided into multiple measurement zones with separate load sensor sets at different positions. This segmentation allows the system to distinguish between different axles by detecting which sensors are activated and analyzing the spatial distribution of weight signals along the bridge length.
Solution Approach 2:
The system dynamically analyzes the temporal sequence of weight signal appearances and disappearances to track axle movement. By monitoring how weight signals evolve over time as vehicles pass, the system can separate and identify individual axle weights even when multiple axles are simultaneously on the bridge.
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 improves the reliability and accuracy of determining axle entry and exit points, enabling conversion of static scales to dynamic weighing with low complexity and cost, and increased robustness without extra components.
Implementation Method 1
a weighing circuit (112) comprising a first set of load sensors (114) and a second set of load sensors (116) coupled to a weight indicator (118), the first set of load sensors (114) being arranged at the first side (104) and the second set of load sensors (116) being arranged at the second side (106)
Implementation Method 2
a measuring circuit (122) arranged to measure at least one unbalance current in the weighing circuit (112) when a vehicle enters or leaves the weighing bridge (102)
Data Source
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AI summary
The present invention relates to a method and a weighing scale for weighing vehicles, the weighing scale comprising a weighing bridge having a first and second side for entering and leaving the weighing bridge; a weighing circuit comprising a first set of load sensors and a second set of load sensors coupled to a weight indicator, the first set of load sensors being arranged at the first side and the second set of load sensors being arranged at the second side; a measuring circuit arranged to measure at least one unbalance current in the weighing circuit when a vehicle enters or leaves the weighing bridge; a processing circuit arranged to determine at least one point in time when wheels of the vehicle enter the first side or leave the second side based on the at least one unbalance current.