Vehicle Body-Suspension Force Estimation Using Sensor Fusion

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Solution Overview

Problem

Current methods for estimating forces at the interface between a vehicle's body and suspension are costly and time-consuming, requiring numerous strain gauges and extensive installation processes, which do not fit within the development cycle of car manufacturers aiming to design lighter bodies while maintaining vehicle dynamics performance.

Innovation Solution

A system utilizing a combination of strain gauges, accelerometers, and an inertial measurement unit, with a processor configured to estimate forces using a combined rigid-flexible car body model, reduces the number of strain gauges needed and accelerates the identification process by employing a state machine and augmented Kalman filter for real-time data processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If numerous strain gauges are used to estimate forces at the body-suspension interface, then measurement precision is improved, but device complexity and installation time increase significantly

Engineering Contradiction:
Improveforce estimation accuracyVSAvoidnumber of strain gauges
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical strain gauge measurement system with a sensor fusion approach combining accelerometers, gyroscopes, and force sensors connected to a processor. This substitution reduces the number of strain gauges needed while maintaining force estimation accuracy through computational mechanics and data fusion algorithms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs multi-functional sensors (accelerometers and gyroscopes) that serve multiple purposes: measuring body acceleration, determining vehicle orientation, and contributing to force estimation calculations. This multi-functionality reduces the overall sensor count compared to using only strain gauges for force measurement.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If numerous strain gauges are installed on the car body, then measurement precision is improved, but installation time and cost increase

Engineering Contradiction:
Improveforce estimation accuracyVSAvoidinstallation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent substitutes the labor-intensive strain gauge installation process with a streamlined sensor assembly that requires fewer mounting points. The integrated sensor unit combines accelerometers, gyroscopes, and force sensors into a compact package that can be installed in significantly less time while achieving comparable or superior measurement accuracy through computational methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses computational models and algorithms that process data from fewer physical sensors to generate accurate force estimates. Rather than physically instrumenting the entire body structure with strain gauges, the system uses a simplified sensor configuration combined with mathematical modeling to replicate the measurement capabilities of a full strain gauge array.

Inventive Principle:
Principle #26Copying

3Measurement precision

If a traditional strain gauge system is used, then force measurement capability is achieved, but the development cycle time is exceeded

Engineering Contradiction:
Improveforce measurement capabilityVSAvoiddevelopment cycle speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the traditional sequential development process with a parallel implementation approach. The sensor fusion system with accelerometers, gyroscopes, and force sensors can be integrated and calibrated simultaneously, eliminating the lengthy sequential installation and calibration process required for traditional strain gauge systems. This enables force measurement capability to be achieved within the compressed development cycle.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs pre-calibrated sensor assemblies and pre-programmed processing algorithms that are prepared in advance. The sensor unit comes pre-configured with the necessary calibration data and the processor contains pre-loaded algorithms for force estimation, eliminating the need for time-consuming on-site calibration and setup during the development process.

Inventive Principle:
Principle #10Preliminary action

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 significantly reduces time and cost while providing accurate force estimation at the vehicle interface, enabling car manufacturers to design lighter bodies with maintained vehicle dynamics performance.

Implementation Method 1

A plurality of strain gauges is positioned by connection points of a car body with a suspension

Methodology Applied
Scientific EffectStrain measurement: Deformation

Implementation Method 2

A plurality of accelerometers is positioned by the connection points

Methodology Applied
Scientific EffectAcceleration measurement: Accelerometer

Implementation Method 3

an inertial measurement unit is also used to remove or reduce the effects of rigid-body motion captured by accelerometers

Methodology Applied
Scientific EffectInertial measurement: Inertia

Data Source

PatentEP3020582B1Identifying forces in a interface between a body and a suspension of a vehicle
Publication Date: 2020.08.05 SIEMENS IND SOFTWARE NV
  • EP3020582B1 patent drawingFigure 1~2
  • EP3020582B1 patent drawingFigure 3

AI summary

Forces in a vehicle interface between the suspension and a body are identified. Rather than using many or all strain gauges, some more easily and rapidly installed acceleration sensors are instead used to measure local deformation. To remove or reduce the effects of rigid-body motion captured by accelerometers, an inertial measurement unit is also used. The forces are estimated from a behavior model accounting for both rigid and flexible motions.