Vehicle Load Distribution Identification Using Pitch Angle
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Solution Overview
Problem
Existing methods for identifying vehicle load distribution, particularly in front-wheel-drive vehicles, face limitations due to the need for resonance spectrum characteristics, which are not apparent in most models, leading to a restricted application range and increased costs.
Innovation Solution
A method and apparatus that calculate the pitch angle of a vehicle using detected speed and longitudinal acceleration, allowing for the estimation of load distribution without dedicated sensors, utilizing the equation θ=F2/k2-F1/k1L, where θ is the pitch angle, L is the wheelbase, and k1 and k2 are suspension stiffnesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resonance spectrum characteristics are used to identify load distribution, then load distribution can be estimated without dedicated sensors, but the method has limited application range in front-wheel-drive vehicles due to lack of apparent resonance characteristics
Solution Approach 1:
The patent changes the measurement parameter from resonance spectrum characteristics to pitch angle characteristics. By detecting changes in pitch angle under different loading conditions, the method achieves load distribution identification without relying on resonance characteristics that are absent in front-wheel-drive vehicles, thereby expanding application range while maintaining cost-effectiveness
Solution Approach 2:
The pitch angle-based method serves as a universal solution applicable to all vehicle types including front-wheel-drive, rear-wheel-drive, and four-wheel-drive vehicles. It replaces the specialized resonance-based method that only works for certain vehicle types, achieving multi-functionality across different drivetrain configurations
2Measurement precision
If load sensors or body height sensors are installed at the suspension to measure load distribution, then accurate load distribution data can be obtained, but installation cost and system complexity increase
Solution Approach 1:
The vehicle's existing motion characteristics (pitch angle changes) are utilized to provide load distribution information. The system serves itself by using natural vehicle dynamics responses to loading conditions, eliminating the need for additional dedicated sensors at the suspension, thereby reducing both cost and complexity while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with a dynamics-based calculation system. Instead of using physical load sensors or body height sensors, the method calculates load distribution from pitch angle data obtained through vehicle motion analysis, substituting a mechanical measurement approach with a dynamics calculation approach
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 reduces the cost of load distribution identification and extends its application to all vehicle models by calculating the difference between front and rear axle loads without the need for load or body height sensors, enhancing systems like ABS and TCS.
Implementation Method 1
detecting a speed and longitudinal acceleration of the vehicle
Implementation Method 2
obtaining, by a processor, a pitch angle of the vehicle according to the driving force and the vehicle speed
Data Source
AI summary
A method for identifying vehicle load distribution includes the steps of: detecting a speed and longitudinal acceleration of the vehicle; when the longitudinal acceleration is less than an acceleration threshold, acquiring a driving force of the vehicle; obtaining, by a processor, a pitch angle of the vehicle according to the driving force and the vehicle speed; and obtaining, by the processor, load distribution of the vehicle according to the pitch angle.