Aerodynamic Force Measurement via Suspension Motion Replication

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Solution Overview

Problem

Existing test equipment finds it difficult to measure and quantify aerodynamic forces acting on a vehicle during operation, as these forces are challenging to replicate and quantify compared to road and steer forces.

Innovation Solution

A test system that includes a force disturbance generator, motion measurement assembly, and actuator devices to replicate the motion or displacement caused by aerodynamic forces, using algorithms to control the actuators and measure the forces applied to determine the equivalent load on a test specimen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If aerodynamic forces are measured directly during vehicle operation, then the force measurement would be accurate, but it is difficult to measure and quantify these forces compared to road and steer forces

Engineering Contradiction:
Improveaerodynamic force measurementVSAvoidaerodynamic force detection
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses an intermediary measurement approach where aerodynamic forces are not measured directly but are derived as a residual force after measuring road inputs through the suspension and calculating the expected body motion. The difference between actual and expected motion reveals the aerodynamic force component, effectively using the suspension system as an intermediary measurement path.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical force measurement of aerodynamic loads with a computational approach using motion sensors and algorithms. Instead of installing force sensors to directly measure aerodynamic forces, the system uses accelerometers and gyroscopes to measure body motion and computationally derives the aerodynamic forces from the equations of motion.

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

2Adaptability or versatility

If test equipment uses actuators to input force to the specimen, then the test can simulate operating conditions, but aerodynamic forces act on the vehicle body directly rather than through the suspension

Engineering Contradiction:
Improvetest condition simulationVSAvoidforce application path
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent inverts the traditional approach by not trying to replicate aerodynamic forces directly through actuators connected to the body. Instead, it measures the actual aerodynamic-induced motion and then uses actuators connected through the suspension to replicate that motion, working backwards from the effect to the cause.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the control parameter from direct force application to motion replication. By measuring body motion parameters (acceleration, velocity, position) during aerodynamic loading and then controlling actuators to replicate these motion parameters, the system achieves equivalent test conditions through parameter transformation rather than direct force replication.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2769195B1Test system for measuring and evaluating dynamic body forces
Publication Date: 2019.02.27 MTS SYSTEMS CORPORATION
  • EP2769195B1 patent drawingFigure 1
  • EP2769195B1 patent drawingFigure 2
  • EP2769195B1 patent drawingFigure 3

AI summary

A test system configured to impart a body disturbance to a test specimen and measure motion or displacement of the test specimen in response to the input body disturbance. The system includes one or more actuator devices (110, 170, 172, 174, 180, 214, 226, 230, 236, 240) configured to replicate motion or displacement of the body (104) imparted through the original input body disturbance utilizing the measured motion or displacement. As disclosed, the system includes algorithms or instructions to generate control parameters (126) utilizing the measured motion or displacement (108) to control operation of the one or more actuator devices. The force applied through the one or more actuator devices to replicate the measured motion or displacement (108) is used to determine the force or load applied to the body (104) via the input disturbance.