Virtual Testing and Subjective Evaluation of Chassis Components in - - PowerPoint PPT Presentation

▶
virtual testing and subjective evaluation of chassis
SMART_READER_LITE
LIVE PREVIEW

Virtual Testing and Subjective Evaluation of Chassis Components in - - PowerPoint PPT Presentation

Oct 10, 2022 141 likes •404 views

IVK Institut fr Verbrennungsmotoren und Kraftfahrwesen Virtual Testing and Subjective Evaluation of Chassis Components in the Stuttgart Driving Simulator IPG Apply & Innovate, Karlsruhe September 20 21, 2016 Dipl.-Ing. Minh-Tri

slide-1
SLIDE 1

IVK – Institut für Verbrennungsmotoren und Kraftfahrwesen

Virtual Testing and Subjective Evaluation of Chassis Components in the Stuttgart Driving Simulator

IPG Apply & Innovate, Karlsruhe September 20 – 21, 2016 Dipl.-Ing. Minh-Tri Nguyen

slide-2
SLIDE 2

I. Motivation and Purpose II. Principle of Driving Dynamics Evaluation in the Simulator III. Implementation of the Driving Scenario

  • IV. Human’s Perception of Vehicle Motion

V. Evaluation of Chassis Components

  • VI. Summary

9/21/2016 University of Stuttgart 2

Overview

slide-3
SLIDE 3

Motivation and Purpose

I.

slide-4
SLIDE 4
  • Integration of the driving simulator in the process of chassis development

and driving dynamics Vision: Holistic approach for vehicle development

9/21/2016 University of Stuttgart 4

Motivation and Purpose

Stuttgart Driving Simulator Vehicle Aeroacoustics Wind Tunnel IVK Driving Dynamics Test Bench

slide-5
SLIDE 5
  • Improving system understanding in early stages of the development

process by subjective evaluation

9/21/2016 University of Stuttgart 5

Motivation and Purpose

Definition, Concept Simulation Prototype Building, Validation Tuning, Optimization SOP Subjective Evaluation Objective Data Testing Simulation

slide-6
SLIDE 6
  • Approach for driving dynamics evaluation in the driving simulator

9/21/2016 University of Stuttgart 6

Motivation and Purpose

Use Case, Benefits, Limits. Customized Modeling and Simulation

  • Subjective

driving impression

  • Comparison to

Reality

slide-7
SLIDE 7

Principle of Driving Dynamics Evaluation in the Simulator

II.

slide-8
SLIDE 8
  • Common process for subjective and objective evaluation of driving

dynamics

9/21/2016 University of Stuttgart 8

Principle of Driving Dynamics Evaluation in the Simulator

δ

ψ, ϑ, φ, … Driver’s reaction Vehicle’s reaction

Disturbances Driver Vehicle

  • Subj. Evaluation
  • Obj. Data

Correlation subj.- obj.

?

slide-9
SLIDE 9
  • Driving Simulator process for subjective evaluation of driving dynamics

9/21/2016 University of Stuttgart 9

Principle of Driving Dynamics Evaluation in the Simulator

δ

Ψ‘, ϑ‘, φ‘

Disturbances Driver Simulator Model Motion Cueing

On/Off Ψmod, ϑmod, φmod Model’s reaction Driver’s reaction Simulator’s reaction

  • Subj. Evaluation

Correlation subj.- obj.

slide-10
SLIDE 10

Implementation of the Driving Scenario

III.

slide-11
SLIDE 11

9/21/2016 University of Stuttgart 11

Requirements for the Vehicle Model Implementation of the Driving Scenario

Computing Time Subjective improvement due to model complexity

Limit of Real Time Capability

Accuracy of Modeling

slide-12
SLIDE 12

9/21/2016 University of Stuttgart 12

IPG CarMaker Vehicle Model for Driving Dynamics Evaluation Implementation of the Driving Scenario

Parameterized MF 5.2 Suspension Elements Kin./ Elakin. (.skc) Pfeffer Steering

0,0 0,2 0,4 0,6

  • 15,0
  • 5,0

5,0 15,0

Aerodynamic Coeff. 5-Mass Model With Rigid Body

  • 30
  • 20
  • 10

10 20 30 500 1000 1500 2000 Force-distance-graph damper

  • 1.5
  • 1
  • 0.5

0.5 1 1.5 500 1000 1500 2000 Force-velocity-graph damper

Enhanced Damper- Topmount-Model

slide-13
SLIDE 13
  • Scenario

Driving on Autobahn with road impact, e.g. bumps, bridge joints and road unevenness

9/21/2016 University of Stuttgart 13

Transferring On-Road Scenario to Virtual Reality Implementation of the Driving Scenario

Focus on: Exact reproduction of vehicle’s body motion Subjective driving impression comparable to reality

Autobahn Test Run VR in the Simulator

slide-14
SLIDE 14

Superposition of synthetic road spectrum and impulses on vehicle body

9/21/2016 University of Stuttgart 14

Structure of Excitation Implementation of the Driving Scenario

10

  • 2

10 10

2

10

4

10

  • 20

10

  • 10

10 Frequency [Hz] Heave (f) [m²/Hz] Heave Motion CG

Synthetic Road Spectrum Excitation Measured Vehicle’s Motion after Vertical Impact

𝐺

𝑦

𝐺

𝑧

𝐺

𝑨

CG Forces and Moments Referred to CG

𝑏𝑦 𝑏𝑧 𝑏𝑨 𝜒 𝜘 𝜚 𝑁𝑦 𝑁𝑧 𝑁𝑨

1000 2000 3000 4000 5000

  • 0.1
  • 0.05

0.05 0.1 Length [m] Heave [m]

slide-15
SLIDE 15

Human’s Perception of Vehicle Motion

IV.

slide-16
SLIDE 16

Using defined excitation to generate criteria of perception:

  • General statements about the “Threshold of Perception” regarding to the

Autobahn scenario

  • Evaluating the “Just Noticeable Difference” due to impulses

9/21/2016 University of Stuttgart 16

“Threshold of Perception” and the “Just Noticeable Difference” Human’s Perception of Vehicle Motion

Driver Virtual Vehicle Model Excitation

Threshold of Perception Noticeable Difference

slide-17
SLIDE 17
  • Experimental measuring of detected impulses
  • Correlation between the intensity of impulses and the stochastic road

excitation

9/21/2016 University of Stuttgart 17

Driver’s Task to Evaluate the Threshold of Perception (ToP) Human’s Perception of Vehicle Motion

ToP

200 205 210 215 220 225 230

  • 5
  • 4
  • 3
  • 2
  • 1

1 2 3 4 5 Time [s] Vertical Acc. [m/s²]

0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 RMS of Vertical Excitation [m/s²] Amplitude Impulse [m/s²] Correlation - Impulse - Excitation

Body Acc. in m/s² Time in s RMS Vertical Road Excitation AMP Impulse Correlation AMP / RMS

𝑏𝐽𝑛𝑞 = 𝒒 ∗ 𝑏𝑠𝑝𝑏𝑒 + 𝒓

slide-18
SLIDE 18

Linear correlation between impulse amplitudes and RMS of vehicle’s vertical acceleration due to road disturbances.

9/21/2016 University of Stuttgart 18

Results of the ToP Human’s Perception of Vehicle Motion

0.2 0.4 0.6 0.8 1 1 2 3 4 5 0.2 0.4 0.6 0.8 1 .1 .2 .3 .4 .5 .6 .7 0.2 0.4 0.6 0.8 1 .5 1 .5 2 .5 Threshold of Perception 0.2 0.4 0.6 0.8 1 1 2 3 4 5 0.2 0.4 0.6 0.8 1 .1 .2 .3 .4 .5 .6 .7 0.2 0.4 0.6 0.8 1 .5 1 .5 2 .5 Threshold of Perception

0.2 0.4 0.6 0.8 1 1 2 3 4 5 RMS of vehicle`s vertical acc. due to road disturbance in m/s² Amplitude of Vertical impacts in m/s² Threshold of Perception

  • detected
  • non-detected

Separation of Vehicle Motion

slide-19
SLIDE 19
  • Experimental measuring of three impulses in a row (3AFC-Method)
  • Probability of detecting a difference between two impulses

9/21/2016 University of Stuttgart 19

Driver’s Task to Evaluate the Just Noticeable Difference (JND) Human’s Perception of Vehicle Motion

JND

0.5 1 1.5 2 2.5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

540 541 542 543 544 545 546 547 548 549 550

  • 2
  • 1.5
  • 1
  • 0.5

0.5 1 1.5 2

Body Acc. in m/s² Time in s AMP Impulse Probability in % Psychometric Function

𝑄(𝑦) = 1 1 + 𝑓

𝑦−𝒅𝒕 𝒃𝒕

1st 2nd 3rd

𝒃𝒕 = JND 𝒅𝒕 = x(P50%)

> <

slide-20
SLIDE 20

9/21/2016 University of Stuttgart 20

Results of the JND Human’s Perception of Vehicle Motion

  • Fitting the psychometric function based on the probability of perceived

impulses

  • Calculation the JND by evaluating the impulse intensity at the probability
  • f 50% and 75%

0.5 1 1.5 2 2.5 0.2 0.4 0.6 0.8 1 Relative Stimulus Intensity Probability of Perception in 100% Psychometric Function - Vertical Dynamics Impulse

50% JND

* measured impulse

  • Fitted sigmoid fun.

75%

slide-21
SLIDE 21

Evaluation of Chassis Components

V.

slide-22
SLIDE 22

9/21/2016 University of Stuttgart 22

Comparison of Vehicle Variants by the Perception of Road Impacts Evaluation of Chassis Components

ToP and JND of vertical impulses

60 62 64 66

  • 4
  • 3
  • 2
  • 1

1 2 3 4 Time in s Body Acc.z in m/s2 60 62 64 66

  • 4
  • 3
  • 2
  • 1

1 2 3 4 Time in s Body Acc.z in m/s2 Threshold of Perception

Perceptible as impulse

  • Vehicle 1 (orig.)
  • Vehicle 1
  • + 20 % Stiffness
  • + 20 % Damping
slide-23
SLIDE 23

9/21/2016 University of Stuttgart 23

Comparison of Vehicle Variants by the Perception of Road Impacts Evaluation of Chassis Components

ToP and JND of vertical impulses

60 62 64 66

  • 4
  • 3
  • 2
  • 1

1 2 3 4 Time in s Body Acc.z in m/s2 60 62 64 66

  • 4
  • 3
  • 2
  • 1

1 2 3 4 Time in s Body Acc.z in m/s2 61.75 61.8 61.85 61.9 61.95 1.7 1.8 1.9 2 Time in s Body Acc.z in m/s

2

Noticeable as difference

> JND

slide-24
SLIDE 24

Summary

VI.

slide-25
SLIDE 25
  • Improved system understanding by subjective evaluation of driving

dynamics in early stages of the development process.

  • Thresholds of perceptions can be used to evaluate driving dynamics

topics to get additional objective data and better correlations.

  • Compared to real on-road tests new approaches and analysis can be

implemented.

  • With this simulation environment the evaluation of driving dynamics can

be more experienced.

9/21/2016 University of Stuttgart 25

Summary

slide-26
SLIDE 26

Thank you!

e-mail phone +49 (0) 711 685- fax +49 (0) 711 685- University of Stuttgart Pfaffenwaldring 12 D-70569 Stuttgart Dipl.-Ing. Minh-Tri Nguyen 65889 65710 IVK – Institute of Internal Combustion Engines and Automotive Engineering Minh-Tri.Nguyen@ivk.uni-stuttgart.de