Leaf Spring Suspension Axle Load Estimation With Hysteresis Correction
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Solution Overview
Problem
Existing suspension systems with metallic leaf springs face challenges in accurately determining axle loads due to hysteresis properties, making it difficult to measure force or load directly, and requiring additional strain gauges or system interventions.
Innovation Solution
A method and suspension system that measure the vehicle body's distance relative to the chassis, using hysteresis-adjusted prediction to estimate axle loads by referencing stored hysteresis curves, allowing for accurate determination and continuous correction of axle load projection values, even with trapezoidal springs exhibiting pronounced damping behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional strain gauges or measuring devices are installed to directly measure axle load, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a control unit as an intermediary that processes signals from existing distance sensors and applies hysteresis correction algorithms. This mediator transforms incomplete measurement data into accurate axle load values without requiring direct force measurement devices, thereby maintaining measurement precision while avoiding additional complex hardware
Solution Approach 2:
The patent replaces direct mechanical force measurement (strain gauges) with a computational approach using distance measurements and hysteresis correction algorithms. By substituting mechanical measurement with electronic sensing and mathematical processing, the system achieves accurate axle load determination without complex mechanical sensing equipment
2Measurement precision
If hysteresis correction is applied to improve axle load determination accuracy, then measurement precision is improved, but loss of time occurs due to loading/unloading processes
Solution Approach 1:
The patent performs preliminary actions by continuously monitoring distance measurements and pre-calculating hysteresis correction values during vehicle operation. The control unit maintains ready-to-use correction data that can be immediately applied when axle load changes are detected, eliminating the need to wait for complete loading/unloading cycles before correction can be applied
Solution Approach 2:
The patent implements feedback by continuously comparing measured distance values with hysteresis curve references and automatically adjusting axle load calculations in real-time. This closed-loop feedback system ensures that correction values are continuously updated and applied without time delays, maintaining measurement precision while minimizing time loss through automated real-time processing
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
Enables reliable and efficient estimation of axle loads with minimal effort, using cost-effective distance measuring devices and updating hysteresis fields to improve accuracy over time, suitable for regulating and controlling vehicle dynamics.
Implementation Method 1
measuring a measurement distance of the vehicle body relative to the chassis, which as such is initially influenced by hysteresis effects
Implementation Method 2
the multiple spring layers or spring leaves rub against each other and thereby can absorb kinetic energy
Implementation Method 3
Such trapezoidal springs have a pronounced damping behavior
Data Source
AI summary
A method for determining an axle load and a suspension system are configured for a vehicle having at least one leaf spring connected at its ends in spring holders of a vehicle body and connected in its central region to a chassis of the vehicle. The following steps are performed: measuring a measurement distance of the vehicle body relative to the chassis; determining whether there is currently a loading or unloading process of the vehicle, determining a relevant hysteresis curve of a pre-stored hysteresis field depending on the determination of a loading or unloading process, and determining a current axle load projection value from the measurement distance and the relevant hysteresis curve. A loading process criterion and an unloading process criterion may be considered. The determined axle load projection value thus serves as a projected or estimated axle load. Furthermore, the hysteresis field can be updated.