siemens digital industries software architecture-driven e

SIEMENS DIGITAL INDUSTRIES SOFTWARE

Architecture-driven E/E Systems Development Flow

Hans-Juergen Mantsch, Product Management Director, Capital SystemsSiemens Digital Industries Software

siemens.com/software

http://www.siemens.com/software

Across industries, electrical and electronic (E/E)

systems are trending towards increasingly unman-

ageable levels of content and complexity. The

growth in E/E content and complexity requires

new approaches for developing E/E architectures.

How can such approaches be adopted, and how

can these complex architectures be optimized?

This paper explains Siemens’ E/E systems and

architecture design solutions. These advanced

solutions create a powerful digitalized E/E archi-

tecture thread across the product and application

lifecycles, supporting model-based systems engi-

neering (MBSE) methodologies and generating

enormous customer value.

Importantly, the paper explores the strategic

position of the E/E architecture and shows how a

digital thread pivoting around the E/E architecture

can be built: from requirements and systems

modelling, through electrical system, network and

embedded software design, to electronic control

unit and vehicle simulation.

1. Innovation Driven Complexity

Various industries, including automotive, aero-

space and heavy equipment, are experiencing a

huge explosion in “innovation-driven complexity”.

Complexity is exploding due to the introduction of

innovative new technologies including autonomy,

electrification, connected vehicles and data

services. A common characteristic of these innova-

tions is their basis in E/E systems - electrical,

networks and embedded software. This has driven

architectural evolutions to support the greater

demand on the E/E systems.

For example, over the years more and more ECUs

have been added to the automotive architecture.

The ever increasing number of ECUs has

culminated to a point where modern vehicles have

no available space or network bandwidth for addi-

tional ECUs. Recently, the main driver of complexity

has shifted to embedded software as automakers

have begun consolidating ECUs and their features

into a smaller number of high performance compu-

tation nodes.

In addition, cars are no longer isolated devices.

Automakers are enabling their vehicles to connect

to the internet to leverage cloud computing power

and interface with infrastructure services.

Connecting the vehicle to wireless networks, such

as 4G and 5G, demands implementing a sophisti-

cated security strategy to prevent threats to

customer privacy or safety. For example, gateways

that separate in-vehicle and external networks and

advanced firewalls can help ensure that external

actors are unable to access the vehicle’s internal

networks.

1.1. Complexity Metrics

Two key metrics demonstrate the increase in “inno-

vation-driven complexity”: the number of lines of

software code in the vehicle and the number of

network signals on the in-vehicle networks.

In 2014, Deutsche Bank conducted a study in which

they measured rising vehicle complexity based on

the software lines of code (SLOC) and the number

of network signals implemented within a typical

vehicle at various times. The study predicted that

the average vehicle in 2020 would contain 30

million SLOC and 10,000 network signals, both

of which were at least double what was reported

for a vehicle from 2012. This prediction, however,

has proven to fall short of reality. According to

customers, the typical vehicle in 2020 has 150

million SLOC and 20,000 or more network signals.

Abstract

SIEMENS DIGITAL INDUSTRIES SOFTWARE 2

White Paper – Architecture-driven E/E Systems Development Flow

We can see that the worst-case prediction from

2014 has by far been outpaced by reality. Dealing

with this complexity is one of the most substantial

challenges facing the automotive and aerospace

industries.

1.2. Implications across the Industries

Companies are faced with the reality that traditional

methods of product development that have been

used up to this point will no longer suffice.

To cope with the huge levels of innovation-driven

complexity, new methods and strategies of devel-

oping products must be adopted across all indus-

tries. The need for new development methodologies

is only more apparent when considering advanced

technologies, such as autonomous driving function-

ality which requires processing large amounts of

visual sensor data within a reasonable power

budget.

In the aerospace industry, vehicle automation is

already quite common. Autopilot systems control

airplanes for large portions of in-flight operations

and can even land the aircraft in cases where the

pilots cannot. In addition activity surrounding the

development of autonomous agricultural equipment

has increased considerably. Compared to autono-

mous passenger cars, agricultural machines operate

in much more controllable environments and are

subject to less stringent requirements. As a result,

we may see commercially viable autonomous trac-

tors, combines, harvesters and more in a relatively

short timeline.

1.3. Capital Evolution

To support companies as they confront and

overcome the challenges of innovation-driven

complexity, Siemens Digital Industries Software

has enhanced the Capital electrical systems and

wire harness engineering solution, a product with

a significant history in E/E systems development.

Capital includes powerful tools for E/E systems and

architecture design that help customers develop and

optimize innovative and integrated E/E systems

designs. Then, Capital also helps deliver the E/E

architecture output that feeds into the subsequent

software and electrical design stages.

The exploding complexity of E/E systems demands

the adoption of advanced and integrated E/E

systems development tools today to deliver tomor-

row’s advanced products in the automotive, aero-

space and industrial machinery industries. More

importantly, product development can longer occur

as an isolated task, but must happen in the context

of a fully digitalized thread (MBSE).

To enable this digitalized thread, we integrate E/E

systems development with other engineering

domains, including mechanical CAD (MCAD) and

product or application lifecycle management (PLM/

ALM) systems, to deliver a truly digitalized system

development thread. This enables the E/E Systems

design flow to be part of a wider program lifecycle

within organizations.



2. MBSE: Framework and Integrations

E/E systems development is integrated into an

overall MBSE flow through deep connections with

PLM and ALM systems, such as Teamcenter, simula-

tion solutions, MCAD software and other domains

that make up the complete product development

process. This enables a continuous product engi-

neering process, with information constantly

flowing between domains to ensure that each

engineer and team has access to the most up-to-

date data at any given time. MBSE ensures not only

accuracy, but supports better collaboration among

teams, and comprehensive traceability of design

progress.

2.1. MBSE Framework

Key features of the MBSE framework:

• Multi-domain orchestration across engineering

disciplines enables coherent configuration

management, traceability, and capture of engi-

neering deliveries to drive simulation, validation

and verification processes.

• An upfront system definition that aims to serve all

domains with requirements, failure modes and

effects analyses (FMEA), system models and other

multi-domain information models.

• Early simulations on product models enable

large-scale cross-domain verification and product

optimization and trade-off assessments.

2.2. MBSE Product Lifecycle and Multi-Domain

Information Model

Capital is fully embedded into the MBSE process,

delivering the capability to design and optimize

integrated E/E systems, and the implementation of

corresponding electronics, electrical systems, soft-

ware and networks. Let’s explore how MBSE is able

to connect all these development disciplines, and

especially E/E systems development into a coherent

process and design flow.

First, a sophisticated multi-domain information

model allows the E/E systems engineering solution

to capture all product and process related informa-

tion in one place. This information includes feature

and function definitions, requirements, test cases,

feature and product variability models, configura-

tions and any other information needed to describe

the intended product and all related processes,

workflows and release management related

information.

Typically, the product and process information and

models are not created from scratch but originate in

higher abstraction models. These higher abstrac-

tions are usually designed in system engineering or

system modelling solutions, and can be integrated

into the multi-domain information model. The

domain specific engineering solutions for the engi-

neering disciplines then can draw from the informa-

tion and models to drive their specific designs.

These domain-specific designs can also be

connected directly into the overall information

model using various demand-created views or

interfaces. This allows the E/E systems designer

to create the E/E architecture in the context of

the holistic product structure. Engineers can also

leverage important metrics to drive successful E/E

architecture, and subsequent product, designs.

The technical view of the MBSE-enabling multi-do-

main information model is abstracted from the

engineer. Users are only exposed to the underlying

data through sophisticated on-demand and

web-based views. These views are dynamic and

provide data in context of the related engineering

tasks, designs and workflow options. This ensures

that engineers are only presented with information

relevant to their tasks.



3. E/E Systems and Architecture Design

E/E systems and architecture design is an important

piece of this multi-domain information model and

critical to answering the challenges of complexity

in modern products. One of the most effective

strategies to addressing the challenge of innova-

tion-driven complexity is to support continuous

integration of the software and hardware lifecycle,

through ideation, design, implementation and

operation of the product.

3.1. E/E Systems and Software Design

Capital Systems supports such continuous integra-

tion by implementing an E/E systems-driven devel-

opment approach that is fully integrated into the

wider enterprise. The E/E systems development

stage directly feeds architectural proposals for the

network and electrical domains. At the same time,

leveraging data from E/E systems development

enables engineers to balance the hardware vs.

software allocation impact, optimizing the parti-

tioning of the vehicle architecture based on real-

time metrics. These metrics are extensible to include

or measure the effect of changes relative to

design guidelines, supporting trade-studies and

viability checks prior to detail design work begin-

ning. As a result, engineers are able to deliver

optimized architectural proposals to each engi-

neering domain to implement the hardware, soft-

ware, electrical and network domains of the vehicle.

The metrics created during the architecture design

phase can also inform decisions on hosting vehicle

applications locally or in the cloud, including the

consideration of network latency and bandwidth

limitations that can affect application performance.

This sort of analysis is especially important while

partitioning safety critical functionality, such as

automated safety-systems.

Synchronization across the product lifecycle,

continuous integration and coherent complexity

and variability management across all product

design stages and design groups is crucial to

effectively address the challenge of modern product

complexity.

3.2. Electrical Lifecycle

Walking through the lifecycle of a network signal

within the electrical engineering domain provides

an illustrative example of how the E/E systems

design can drive downstream design processes.

Consider two functions, A and B, which are

connected via a signal at the system-level design

abstraction. Each of the functions and the signal

are tied into the multi-domain information model

through Teamcenter requirements, parameters,

validation and test cases and the general product

context made available via links and views.



Through rule-based automation, Capital performs

a set of transformations which translate the func-

tions, A and B, into appropriate devices, electrical

parts with context specific connectors and, finally,

harnesses with harness bundles, fixing material and

harness connectors. The signal-connecting

functions A and B are transformed first into a

electrical net representing the multiplexed network,

then into a shielded twisted pair for the physical

electrical implementation, a harness and lastly into

the bill of process for manufacturing the wiring

harness.

During the automated transformation, or design

synthesis, process, Capital keeps a record of the

identity, links and dependencies between the indi-

vidual artefacts within the different design abstrac-

tions. This establishes traceability from the

manufacturing work instructions all the way up

to the functions, function signals and, of course, to

the product context stored in Teamcenter managed

requirements and test cases.

3.3. Network & Software Lifecycle

What if we look at the same functions A and B, but

from the software and network perspective within

the E/E systems design process?

Through rule-based automation and Capital’s

built-in synthesis technology, the functions can be

transformed into software components, allocated to

specific ECUs, embellished with software behavior

models and configuration information to run on top

of a hardware and software platform within the

targeted ECUs.

As the functions are allocated to different ECUs,

the associated signal is transformed into a network

signal on a multiplexed network and, using timing-

driven network synthesis, packaged into the appro-

priate optimized network frame. Gateways can then

be configured to enable optimized network trans-

mission according to signal priority and the timing

budget allocated to the signal.

The automatically created traceability helps achieve

certification and meet safety requirements. Users

can trace from the functions and signals to the

network input/output, and from the function down

to the specific embedded application configuration

running in the ECU.

3.4. End-to-end Traceability across the E/E

System Integration

Capital’s robust digital thread and automation

capabilities enable the creation of a design flow

unmatched in its capability to exploit automatically

created traceability. Functional models captured

from the multi-domain information model in

Teamcenter are brought into Capital before being

allocated into a vehicle-level view of the topology.

Capital then synthesizes the logical architecture at a

vehicle level for all model variants derived from the

various vehicle configurations. The individual logical

systems are outputs of this process.

Each architecture developed can be saved with the

associated metrics so that trade-off studies of

multiple architectures can be performed. These

studies help engineers to identify the best imple-

mentation option through data-driven metrics

rather than gut feelings. These results of the archi-

tecture trade-off studies are then delivered down-

stream to each of the E/E engineering and

implementation groups.



The traceability across engineering domains can be

exploited at any time. In this example, any element

of the electrical implementation of a network

topology can be traced all the way back to the

requirements managed in Teamcenter, or indeed

to any of the Capital design abstractions, either

upstream or downstream. As an example, the

functional safety criticality of an electrical pin,

part of a multiplexed network connecting ECUs or

line-replaceable units (LRUs), can be assessed in

the context of the functional source, the platform

implementation and test and validation cases.

4. EE Systems Integration Flow

Now we will discuss the steps of the overall process

when the E/E systems design flow is integrated into

the wider enterprise design and implementation

process.

The process begins with the block marked with the

letter [A]. This block shows the Teamcenter product

definition, requirements engineering and system

engineering model. This highest abstraction of the

product composition includes the interfaces

between blocks that model the information that

needs to be transmitted between the multi-domain

system blocks.

Block [B] describes the carry-over designs and

related data in various engineering level details, as

well as data defined in industry standards that are

merged into the system models received from

Teamcenter Systems Modelling Workbench. The

function designs step [C] transform and decompose

the system functions into function designs that are

enriched with domain-specific details to update the

design data carried over from the previous level, or

to create extensions with new functional models.

The domain-enriched function designs replace the

abstract interface definitions from the system

engineering level with low-level domain details.

These enriched function designs also refine and

extend the functional content to the E/E architecture

scope.

The E/E platform designs, as shown in block [D],

capture the logical and physical abstractions of the

architectural implementation. Physical platforms

can be created by importing data from the mechan-

ical CAD environment. These physical platforms

capture the exact physical dimensions, space and

length of the E/E systems implementation to reserve

space in the functional deployment. The E/E archi-

tect can either manually deploy functions to compo-

nents in the architecture, such as ECUs and

assemblies, or use rule-based automation to assign

these functions automatically. Then, function

signals are assigned to communication and ground

carriers as defined in the higher-level system

requirements, or in design rules defined in the

carry-over content.



Capital Insight calculates domain-specific metrics

and key performance indicators for physical,

software, networks and hardware designs. These

metrics help incrementally refine function models

and platform allocations until the designs meet

technical and cost targets. These built-in metrics can

display weight, wire lengths, space consumption,

peak power consumption, RAM and ROM utilization,

CPU utilization, network load and much more. This

allows the engineers to quickly iterate and compare

implementation alternatives.

Once the best implementation options have been

identified, architectural proposals can be extracted

and delivered to downstream design stages.

Architectural proposals can be extracted for the

network and software architecture, electronics

hardware and the logical systems for the electrical

distribution systems. After generating the logical

schematics and feeding them into the Capital

Electrical Implementation flow, the boxes [F] and

[G] show the detailing of the electrical distribution

systems up to the design of the wiring harness,

manufacturing and formboard design.

The boxes [H] and [I] show the software and

network design process as well as how they inte-

grate using standard industry formats, such as the

AUTOSAR ARXML meta-model. The network design

stage [I] uses a generative synthesis process to pack

the multiplexed networks signals, created in the E/E

architecture, into messages on both the in- and

off-vehicle networks. This results in the network IO

and communication matrix in domain formats such

as ARXML and FIBEX, and allows the engineer to

create the AUTOSAR ECU extract.

After the software component design is finished,

the code skeleton can be generated. The embedded

application software code is then created, tested and

simulated, as shown in boxes [J] and [K]. The code is

then merged into the ECU extract and integrated



This overview shows how Siemens Digital Industries

Software’s integrated solutions deliver an

unmatched E/E systems development flow for

creating automotive or aerospace architectures.

The flow begins with the multi-domain system

modelling stage that captures the system definitions

and system models in a fully managed environment.

This managed environment provides services for

requirements engineering, change management,

workflow support and asset management. The

abstract multi-domain system models are then

integrated in the E/E architecture stage, where they

are interpreted and decomposed into domain-spe-

cific functions representing the hardware, software,

electrical and electronic content of the final

product.

Functions are deployed in vehicle platforms that

represent the logical and physical abstractions of

the architecture, ECUs, networks and hardware

components. Capital’s rule-based automation and

unique synthesis capability drive a highly efficient

distribution of the functions and related function

signals into the platform. Then, built-in metrics

allow the immediate assessment of the financial or

technical cost of an implementation against the

budget defined by KPIs. With these metrics, engi-

neers can rapidly optimize and iterate the

implementation.

The E/E systems architecture can then be interro-

gated to extract software, network, electrical and

hardware domain-specific architecture proposals.

These proposals can be refined in the respective

design tools in the Capital and Siemens product

portfolio. The software and networks design output

can also be combined to support a synthesis driven,

AUTOSAR embedded software implementation

process.

Establishing bi-directional traceability and

supporting coherent lifecycle management along

all design stages enables a compliance-driven

design flow. In such a design flow, the automatically

created traceability allows engineers to create the

security and functional safety related documenta-

tion needed for product certification.

Capital forms an essential part of this flow. Capital

integrates with PLM, ALM, MCAD, simulation and

other solutions from throughout the Xcelerator

portfolio to create a coherent end to end solution.

This solution ensures digital continuity, multi-do-

main traceability, safety and security for the design

of complex automotive and aerospace systems.

Conclusion

onto a virtual embedded ECU target where it can be

configured, compiled, tested and profiled, as shown

in box [L]. Once the embedded application software

has been validated, it is configured to run on the

target ECU hardware by integrating it onto the

respective AUTOSAR basic software stack in box [M].

Product and application lifecycle management

solutions, such as Teamcenter and Polarion, orches-

trate the overall process and provide traceability

along all design and definition stages of the product

lifecycle. The management of these processes

provides workflow support, impact analysis and task

specific views on the progression of the product

implementation.



About Siemens Digital Industries Software

Siemens Digital Industries Software is driving transformation to

enable a digital enterprise where engineering, manufacturing

and electronics design meet tomorrow. Xcelerator, the compre-

hensive and integrated portfolio of software and services from

Siemens Digital Industries Software, helps companies of all sizes

create and leverage a comprehensive digital twin that provides

organizations with new insights, opportunities and levels of

automation to drive innovation. For more information on

Siemens Digital Industries Software products and services, visit

siemens.com/software or follow us on LinkedIn, Twitter,

Facebook and Instagram. Siemens Digital Industries Software –

Where today meets tomorrow.

siemens.com/software

© 2021 Siemens. A list of relevant Siemens trademarks can be found here. Other trademarks belong to their respective owners.

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About the author

Hans-Juergen Mantsch is the Product Management Director for

Capital Systems, the E/E Systems & Architecture Design front-end

of the Capital Solutions portfolio.

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