Vehicle Rollover Risk Estimation via Dynamic Load Transfer Modeling
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Solution Overview
Problem
Self-propelled vehicles equipped with controllable suspension systems face challenges in determining the instantaneous state of the suspension system, leading to potential tipping risks due to unavailable load transfer measurements, which can result in delayed safety interventions.
Innovation Solution
A method that calculates a measured quantity of load transfer from sensor signals and an estimated quantity using a dynamic model, with recalibration of model parameters based on deviations, to continuously assess and mitigate tipping risks by adjusting the center of gravity and mass parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurements are taken by sensors of the controllable suspension system to determine the instantaneous state, then the measured quantity representative of overturning risk is available, but the measurement becomes unavailable when the active suspension is in the fully retracted state or when the driver changes the height of the center of gravity
Solution Approach 1:
The patent introduces an intermediary estimation mechanism that uses a dynamic model and alternative sensor measurements (inertial sensors, kinematic sensors) to calculate load transfer when direct suspension sensor measurements are unavailable. This intermediary approach ensures continuous availability of load transfer data by bridging the gap during suspension retraction or driver intervention periods.
Solution Approach 2:
The system implements feedback by continuously monitoring the availability of suspension sensor measurements and switching between direct measurement mode and model-based estimation mode. When direct measurements become unavailable, the system activates the dynamic model with feedback from inertial and kinematic sensors to maintain accurate load transfer assessment.
2Ease of operation
If a dynamic model with fixed parameters is used to estimate load transfer, then the estimation can be calculated, but the estimated value deviates from the true value when mass and center of gravity height vary significantly
Solution Approach 1:
The patent transforms the static dynamic model into a dynamic adaptive model that continuously updates its parameters (mass and center of gravity height) based on measurements from inertial sensors and kinematic sensors. This allows the model to adapt to varying vehicle conditions while maintaining computational efficiency.
Solution Approach 2:
The system dynamically changes the parameters of the dynamic model by estimating mass and center of gravity height variations using inertial measurement unit data and kinematic sensor data. This parameter adaptation ensures the model remains accurate despite significant variations in vehicle loading and configuration.
3Productivity
If the quantity measured is unavailable for a few seconds, then the system can operate without direct suspension data, but the risk of tipping goes out of control and the vehicle may tip over
Solution Approach 1:
The system prepares for measurement unavailability by maintaining a ready-to-use dynamic model that can immediately take over when suspension sensors become inactive. The model is pre-configured with inertial and kinematic sensor inputs, enabling seamless transition without safety gaps.
Solution Approach 2:
The patent ensures continuous load transfer assessment by combining direct suspension measurements during availability with model-based estimation during unavailability. This continuity of useful action prevents safety gaps and ensures uninterrupted monitoring of overturning risk.
Data Source
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AI summary
The invention relates to a method comprising: a first step of calculating, on the basis of a plurality of signals delivered by sensors (28, 29) of the controllable suspension system, a measured quantity (TCm) as an active value (TC) of a load transfer; a second step of calculating an estimated quantity (TCe), on the basis of signals delivered by kinematic sensors (50-58) placed on-board the vehicle and a dynamic model of the vehicle, said estimated quantity being taken as an active value of the load transfer when the measured quantity is not available; a step of evaluating the risk of rollover on the basis of the active value (TC) of the load transfer; and, in the event of an increased risk of rollover, a step of emission of a safety signal (S).