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tance functions [1, 2]. This is imperative applying the approach is on calibrating this information to the driver assistance
in particular for validating complex sce- and testing functions regardless of the function being tested. This evaluates the
narios effectively, not least for safety and sensors that are used. identified road situation and, if neces-
cost reasons as well as from the aspect sary, triggers an action. In the visualis-
of reproducibility (above all highly FUNCTIONALITY AND COMPONENTS ation, the test engineers in the vehicle
dynamic and complex scenarios). Fur- see the real-world test environment, the
thermore, the number of test scenarios The ViL test method is based on combin- virtually generated target objects that
needed for validation on the test track ing a real-world test vehicle with virtual move about on the real-world test track,
and the number of real-world test kilo- objects and scenarios. To generate a criti- and experience the test vehicle’s real-
metres in the field are growing as the cal situation, virtual target objects are world response (for example in the form
degree of automation increases, FIGURE 1. added to the real-world test environment. of a visual-acoustic warning, an emer-
The gap emerging in the validation These are shown on a mobile device gency braking, avoidance or stopping
process can be bridged by means of the (for example a tablet) in the wind- manoeuvre). In technical terms, this is
Vehicle-in-the-Loop (ViL) approach shield using an augmented reality app, realised using five components which,
described in this paper as a way of com- FIGURE 2. Virtual sensors detect the apart from the central control compo-
bining simulation and real-world tests in superimposed objects and communicate nent, can be exchanged or adapted to
an appropriate manner, FIGURE 1. This
new approach also demonstrates a way
of permitting the progressive develop-
ment of functions through testing and Until now
validation. Future
Future with ViL

DEMANDS ON THE VEHICLE-IN-
THE-LOOP APPROACH
The basic idea in testing driver assistance Effort
systems in the real-world vehicle is to gen-
erate a critical driving situation with suit-
able tools and then evaluate the response
Vehicle
from the assistance system. To make the (proving ground,
tests reproducible and as realistic as possi- MiL/SiL HiL ViL street)
ble, for example in testing emergency Reality
braking systems, collision-tolerant target FIGURE 1 The effort of validating future driver assistance functions is set to increase, revealing a gap
objects are used for representing vehicles, between simulation-based test methods and real-world test drives which can be bridged by the Vehicle-
pedestrians and cyclists [3]. in-the-Loop (ViL) approach (green line) in the future (© IAV)
Increasingly complex traffic situations
involving various and several road users
as well as driving situations of a more
dynamic nature are demanding new
approaches for safe and resource-friendly
testing. The ViL approach presented in
this paper aims at bridging the gap
between real-world vehicle tests and vir-
tual scenarios and providing a way of
seamlessly integrating this into the exist-
ing processes for testing and validating
driver assistance functions. In this
context, the approach must meet the
requirement of moving the real-world
vehicle in a real-world test environment
into which virtual objects are fed. The
aim is not to embed the vehicle in a
purely virtual environment but to ensure
real-world conditions for the greatest
possible number of testing components,
FIGURE 2.
A further demand on realising the test
method is a modular structure that pro-
vides maximum flexibility to allow for FIGURE 2 The basic idea behind the ViL approach is to add virtual objects and scenarios to the real-world
the varying conditions. The focus of test environment (© IAV)
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