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The AEBS for VRU protection commonly uses sensor fusion to increase chance of
object detection and correct discrimination. Usually RADAR(s) and mono-camera
system are combined to accurately detect the position of a pedestrian or cyclist in
potential danger zone, than classify a detection to avoided (or limit) number of
potential false-positives [11, 15]. Fig. 1 shows a possible system layout.
The RADAR sensor detects objects, positions it in certain Region of Interest (ROI)
and provides data on relative velocity. The objects position within ROI allows the
camera to crop the image to the part that contains the detection. Based on selected
image processing algorithms, object is confirmed and classified. The position and
velocity of an object allows calculating Time to Collision (TTC). If TTC is below a
certain value, system activates actuation (firstly a warning, than braking in one or
several stages). Similar systems are usually limited in detection range and can be
susceptible to environmental conditions.
3
Passive Safety - Computer Simulations for Injury Mitigations
Computer simulations have been developing concurrently with the rapid growth of
advanced computers. Currently, their contribution to the car designing process is vital.
When the Finite Element Method (FEM) - the technique used to determine the
approximated solution for a partial differential equations on a defined domain - was
started to be used by appropriate software, the complexities of modelling, including
safety issues, could be addressed [17-20]. What is more, Euro NCAP (New Car
Assessment Programme) pedestrian protection ratings released in 1997 were also a
trigger for a fruitful start of virtual tests. Nowadays, numerical simulations constitute
the basis for the Computer-Aided Engineering (CAE) [21-23]. The excessive
development of computation power and the expansion of FEM and MultiBody (MB)
enabled researchers to widen the possibilities and applications to include VRU-to-car
collisions. Numerical simulations are also utilized in order to reduce the costs and
time needed to carry out a full impact test with a pedestrian or cyclist (table 1).
Table 1.
Methods to solve an engineering problem connected with passive safety, basing on [24]
Analytical Method
Numerical Method
Experimental Method
Classical approach
Mathematical representation
Actual measurement
Accurate results
Approximate, assumptions made
Time consuming and
needs expensive set
up
Closed form
solution
Applicable even if a physical
prototype is not available (initial
design phase)
Applicable only for
simple problems
Applicable only if
physical prototype is
available
Real life complex problems
Complete in itself
Certain results must be validated by
experiments and/or analytical method
Destructive in nature
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