CAE as Key Technology for the Multidisciplinary Virtual Product … · 2019-04-01 · CAE as Key Technology for the Multidisciplinary Virtual Product Development of Automotive Audio

CAE as Key Technology for the Multidisciplinary Virtual Product Development

of Automotive Audio Systems

Dr. Alfred J. Svobodnik

Konzept-X

Am Wetterbach 2

76307 Karlsruher

[email protected]

NAFEMS Seminar: „The Role of CAE in System Simulation“

November 8 - 9, 2011 Wiesbaden, Germany

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NAFEMS Seminar

The Role of CAE in System Simulation

Wiesbaden, 8. - 9. November 2011

Copyright 2011 by Konzept-X

CAE as Key Technology for the

Multidisciplinary Virtual

Product Development of

Automotive Audio Systems

Nothing is more powerful than an idea whose time has come.

The Role of CAE in System Simulation

Copyright 2011 by Konzept-X 2

NAFEMS Seminar

Wiesbaden, 8.-9. November 2011

Konzept-X - Executive Partner

[email protected]

Dr. Alfred J. Svobodnik



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§ The Challenge of Automotive Audio

§ Where it all begins: Industrial Design and Concept Studies

§ The Theory of Loudspeaker Simulations

§ Subsystem and Full System Simulation

§ The Basics of Virtual and Automated Tuning of Audio Systems

§ How to Evaluate Product Performance: Auralizations

§ Summary

Agenda


Demonstrate how CAE significantly improves development of audio systems and

generates business benefits

CAE as Key Technology for the Multidisciplinary Virtual

Product Development of Automotive Audio Systems

§ More and more challenging development requirements

§ Reduction of development cycle time

§ Reduction of development and product costs

§ Maintain scope of product plan and goal

§ Specific to Automotive Audio

§ Low product cycle times

§ Driven by consumer industry

§ Subjective rating of product quality

§ Human factor

The Triple Constraints


This is contra-dictionary to the relentless strive for product improvements and

introduction of innovations





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§ Increase CAE penetration

§ From detail engineering to system simulations

§ Frontloaded Virtual Product Development

§ Move CAE upfront in the design process (concept studies)

§ CAE as a complementary tool for industrial design

§ Application of simulation tools such as M-voiD (Multidisciplinary virtually optimized industrial Design)

The Solution


Increase engineering efficiency via multidisciplinary simulations



§ Business benefits

§ Virtual systems as test beds for innovations

§ More freedom in design decisions

§ Design changes can be evaluated without building prototypes

à Speed up development process

à Reduce development cost

à Minimize prototype expense

à Improve product quality

The Benefits of Virtual Development


Design better products in shorter time by application of virtual technologies,

especially CAE





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§ Definition of system due to complexity

§ Various subsystems

§ Interaction of subsystems

§ Boundary of whole system

§ Multiscale models

§ Various physics involved

§ Various disciplines involved

The Challenges of System Simulations


It is essential to have a good understanding of the system, subsystems involved,

and it’s boundaries



Complexity of Automotive Audio Systems


While entry sound systems in Automotive still use simple architectures…





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Complexity of Automotive Audio Systems


… the complexity of Mid, Premium and High-end Sound Systems has increased

dramatically.



Car electronics, bus systems

Amplifier w/ DSP unit Loudspeakers, packaging & integration

Head unit

The Final Challenge: Subjective Perception


Car cabin acoustics and the human being itself have a major impact on the

perceived sound and thus are part of the system



Car cabin

acoustics

Human being



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§ Acoustical system definition is defined by a complex signal and sound path

§ Head unit (music source)

§ Bus system

§ DSP unit computing tuning & features

§ Amplifier output stages

§ Loudspeaker and packaging

§ Car cabin

§ Human being

§ Body

§ In-ear acoustics

§ Brain

The Holistic Signal and Sound Transfer Path


CAE is used for loudspeakers and cabin which connects the electronic world with

the human being



CAE

§ M-voiD is the combination of:

§ Industrial design

§ Simulation (CAE)

§ Auralizations (binaural playback)

§ Enhanced by virtual and automated audio tuning opens the following

possibilities:

§ Develop audio systems on a fully virtual basis

§ Proof concepts and improve functionality

§ Audio development collaborative to car development

The Simulation Environment


CAE connects different subsystems and disciplines and is needed to perform

system simulation





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The Simulation Environment


Building blocks of a virtual development environment of

Automotive Audio systems



Digital Signal Processing (head unit, bus, amplifier) Tuning

Industrial Design Binaural Audio

Psycho-Acoustics &

Subjective Evaluation Multiphysical Engineering Analysis

Industrial Design

Multiphysical Engineering Analysiysis

§ Industrial Design applied in early development phase

(concept studies)

§ Integration of loudspeakers into car interior defined by:

§ Aesthetic design aspects

§ Loudspeaker grilles

§ Position of loudspeakers

§ Functional performance

§ Sound system architecture

§ Packaging

§ Expected sound quality

The Role of Industrial Design & Concept Studies


Design decisions in early design phase drive product quality





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§ Subsystem loudspeaker is a complex multiphysical device

§ Long tradition in loudspeaker engineering to use multiphysical lumped parameter models

§ Early 1970’s series of AES papers on loudspeaker, enclosure and radiation of sound waves

§ Set of 1-dimensional equations: Thiele-Small Parameters

§ Useful approach but with limitations in real-life applications

§ Complex vibration pattern of mechanical parts (non-pistonic motion)

§ Complex sound wave radiation

Theory of Loudspeaker Simulations


A loudspeaker is a complex device that needs advanced CAE technologies to

predict performance



§ Need for CAE tools based on matrix methods

§ Fully coupled electrical-mechanical-acoustical simulation model

required for realistic simulations includes:

§ Motor system

§ Lumped parameter model for voice coil electromagnetics

(FEA for motor system development)

§ Mechanical vibration system

§ Finite element model for the mechanical domain

§ Acoustical system (surrounding air)

§ Boundary element model for the acoustical domain

Multiphysical CAE for Loudspeaker Simulations


Every physical domain needs best-of-class numerical simulation scheme





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Loudspeaker Simulations


Governing system equations behind the fully coupled multiphysical model



Electromagnetics Mechanics Acoustics Electromagnetics Mechanics Acoustics

§ Woofer and subwoofer need resonance volume for reproduction of

low frequencies

§ Acoustical enclosures

§ Due to packaging constraints very odd shaped enclosure geometries

and small volumes

§ Strong influence on vibration of mechanical system, thus strong influence

on radiation

§ Complex geometry leads to complex sound pressure distribution in

enclosure

§ Matrix methods for enclosures as well

Subsystem Loudspeaker/Enclosure Simulation


A similar matrix based approach as for loudspeakers needs to be applied for

subsystem loudspeaker/enclosure as well





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Multiphysical model of loudspeaker can be extended to account for enclosure

(extension of mechanical and acoustical domain)



Loudspeaker:

Electromagnetics

Mechanics

Acoustics

Enclosure:

Mechanics

Acoustics

§ Recently even more challenges in packaging due to hybrid and

electrical cars

§ Designed space needed for batteries

§ Requirement to have almost zero packaging space for enclosures

§ Integrate enclosure into car body

§ Cavities of car body used as enclosure

§ CAE based simulations in early design phase mandatory

§ Additional design requirement to car body development

§ Development of sound system must be done in parallel to car body

development



Trend for integration of loudspeakers into car body structure makes CAE

mandatory for audio system development





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§ Radiation of loudspeaker into car cabin till passenger's ears

§ Small room acoustics of car cabin is another major factor for

perception of sound from loudspeakers

§ Multiphysical model of subsystem loudspeaker/enclosure can be

extended to account for enclosure

§ Extension of mechanical and acoustical domain to represent functional

behavior of car cabin

Acoustical System Simulations


A similar matrix based approach as used so far must be applied to perform

simulations on system level



Acoustical System Simulations


Multiphysical model of loudspeaker, enclosure and car cabin



Subsystem

Loudspeaker/Enclosure

Car Cabin:

Mechanics

Acoustics



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§ Surfaces of interior absorb

and reflect sound waves

§ Very complex material mix

§ Seats

§ Windows

§ Carpets

§ Trim panels

§ Combination of porous

and plate absorbers

The Challenge of Car Cabin Acoustics


Modeling the car cabin is not trivial, especially boundary conditions have to be

carefully considered



Trunk, trim &

floor elements

Rear panel

shelf

Backrest Pillar trim

Dashboard Door trim panel

Front shield

Headliner

PillarFront shield

Sun shields

§ Car cabin modeled by means of a hybrid approach combining

simulation and acoustical measurement

The Challenge of Car Cabin Acoustics


Boundary conditions of simulation model are updated via optimization procedure



Virtual Car

Simulated SPL distribution

Real Car

Measured SPL distribution

Model Update

Optimize BC’s to minimize

SPL error

Updated Simulation Model imulat



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§ System simulations provide additional advantages

§ Advanced visualization of

§ 3D sound field throughout the cabin

§ Reflections of sound waves

§ Radiation of sound waves

§ Updated simulation model opens door for next-generation concept

development based on virtual mock-up

§ System architecture and system content can be optimized in early design

phase

§ Optimization of location and orientation of loudspeakers

Benefits of Acoustical System Simulations


CAE based system simulation significantly improves understanding of sound

reproduction in a car



§ Tuning process is essential step towards functional performance to

fulfill customer and consumer expectations

§ Very challenging acoustical properties of car cabin

§ A car cabin is in fact a very poor listening room

§ Acoustical eigenmodes

§ Reflections

§ Location of loudspeakers

§ Advanced signal processing methodologies used to tune sound

system

Virtual and Automated Tuning of Audio Systems


Tuning process needed to account for bad acoustical properties

of car cabin





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§ Three groups of main parameters

§ Gain levels of each channel

§ Time delays between channels

§ Different types of filters to modify

frequency response of each channel

§ Optimization of tuning parameters must be software based

§ Best practice approach

§ Psycho-acoustical concepts



100’s of parameters have to be software based optimized during tuning process



§ Software must follow tuning process as

typically applied manually by system engineer

§ Perception of sound should be implemented

in software as well (psycho-acoustics)

§ Software based on simulation model of

§ Power amplifier

§ Digital signal processing unit

§ Acoustical footprint of car cabin (microphone array measurement)

§ Perception of sound



Tuning software must be based on multidisciplinary simulation model





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§ Connecting link between simulation and tuning is acoustical footprint

§ Microphone array measurement is performed in the simulation model

as well (virtual measurement)

§ Multiphysical simulation model has been extended to multidisciplinary

simulation model

§ Multiphysical engineering analysis

§ Digital signal processing

§ Psychoacoustics

Simulations and Tuning of Audio Systems


Virtual measurement is the connecting link between different disciplines (CAE

system modeling and tuning)



§ Need to listen to our multidisciplinary simulation model

§ Rating of sound quality is up to now not possible “just by numbers”

§ Listening tests based on advanced statistical methods are necessary to

evaluate audio performance

§ Very last sound transfer path has to be included if we want to listen to

our virtual sound system

§ Head-related transfer function (HRTF)

§ Passenger’s ear drum and inner ear

The Need for Auralizations


Auralizations based on CAE modeling are key to rate sound quality





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§ Binaural room impulse response needs to be simulated

§ Starting point for auralizations

§ Enables us to listen to a virtual audio system capturing all major

acoustical characteristics

(based on binaural playback system with headphones)

§ “Realistic” model of spectral and spatial attributes of the car cabin

§ BRIRs calculated for different head positions

(rotated in horizontal plane)

Ingredients of Auralizations


Simulated binaural room impulse response is the basis for a realistic listening

experience



§ Binaural playback system with headphones and

head-tracker

§ Azimuth orientation of head is “tracked”

§ BRIR’s corresponding to each head angle are addressed, reproducing

important localization cues, and convolved with musical signal

§ Playback system is calibrated to equalize acoustical effects of

pinna/concha and headphone

Ingredients of Auralizations


Now, as we can listen to our sound system, product improvements in very early

design phase are possible





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The Virtual Development Building Blocks


CAE is key for virtual development of audio systems and significantly improves

development process



Digital Signal Processing (head unit, bus, amplifier) Tuning

Industrial Design Binaural Audio

Psycho-Acoustics &

Subjective Evaluation Multiphysical Engineering Analysis

Industrial Design

Multiphysical Engineering Analysiysis

§ Ability to listen to virtual audio system

§ Rate sound quality of the audio system (via advanced statistical

methodologies) in an early design stage

§ Opens door for upfront virtual product optimizations supplementary to

industrial design and concept studies

§ Business benefits realized

§ Frontloaded Virtual Product Development for audio systems

§ Product improvements and innovations

§ Increase engineering efficiency

§ Reduction of R&D cost and prototype expense

The Benefits of Virtual Development


Total virtualization of the development process generates vast business benefits

regarding time, cost and scope





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Konzept-X

Am Wetterbach 2

76307 Karlsruhe, Germany

Copyright 2011 by Konzept-X

[email protected] www.konzept-x.com



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CAE as Key Technology for the Multidisciplinary Virtual Product … · 2019-04-01 · CAE as Key Technology for the Multidisciplinary Virtual Product Development of Automotive Audio