Focusing on the blind spot: Active collision warning systems for mobile machines

on the blind spot: Active collision warning systems for mobile machines

Manoeuvring and reversing are the most frequent causes of
accidents involving mobile machines used on construction sites, in open-cast
and underground mining and agriculture and forestry, as well as municipal and
special vehicles. The Visionary-B active driver assistance system developed by
SICK is designed to monitor the area around and behind mobile machines that is
invisible to the driver. It consists of a 3D vision sensor suitable for outdoor
use which identifies people and objects in the driver’s blind spot and issues a

automated systems for agricultural and forestry vehicles, mobile construction
machines in building construction, civil engineering and mining and municipal
and special vehicles are becoming increasingly important. One area where
sensors are used in mobile machines is to
provide reliable systems that detect the risk of a collision and warn the
driver. The main driving force behind this development is the fact that a large
number of collisions and accidents can be
prevented if the suitable technology
is available to support the driver or machine operator. Active warning
functions are not enough. The assistance system must also be able to
distinguish between different objects depending on their importance for
collision warning purposes. The particular challenges involved in these
applications not only concern detecting and evaluating objects. The sensor
solutions must also be designed to withstand the tough outdoor environments
where the machines are used.

from SICK is a product that meets all of these requirements and also has
another special feature. It has been designed
as an active system. This means that as
soon as an object appears within a defined detection zone, the system gives an
audible and visual signal. In contrast to passive monitoring solutions, the
driver does not need to look constantly at the monitor. Instead, he can concentrate on driving the vehicle, safe in the
knowledge that the system will warn him in good time if a potentially critical
situation occurs.

Visionary-B: Plug and play 3D collision warning system

The role of the Visionary-B
intelligent driver assistance system is to minimise
the risk of collisions when mobile machines pull away, manoeuvre and turn, by monitoring the driver’s blind spot. The
system consists of at least one sensor head, an evaluation unit, a 2D monitor
and all the mechanical and electrical components needed for installation. It is
also a two-in-one solution because it
combines an active 3D sensor for collision warnings with an integral 2D live
camera. This means that the driver can
also see a 2D live image and access recordings of the machine’s previous few
hours of operation. When the system is
installedat the height of between 1 and 2.4 meters, the detection
angle of 105¡ x 90¡ enables it to cover an area behind the vehicle, not visible
to the driver, that is six meters long and four meters wide. The evaluation
unit processes the 3D image data, assigns the objects to different classes based on the measurements, saves the recordings
of the most recent period of operation and uses intelligent algorithms that
enable it to ignore objects which are not likely to cause a collision. At the
same time, it transmits the live image and the alarm signals to the monitor in
the machine’s cab, which issues collision warnings in the form of both audible
and visual signals.

Stereoscopic principle and 3D snapshot technology

To ensure that the collision
warning system is reliable and is accepted
by drivers, it is essential that it consistently identifies hazards and can
distinguish them from the machine’s normal working environment. The object
detection system, which is based on the
stereoscopic principle, is what makes this possible. It can identify the
presence of people and objects and measure their distance from the vehicle. The
cameras in the sensor head take images of the vehicle’s surroundings from
slightly different positions. The evaluation system combines these two
perspectives and calculates the depth of the images, in other words, the third
dimension. On the basis of the 3D image
information, the 3D vision sensor can identify the width and height of the
objects. This allows the system to
distinguish between people and objects that could cause a collision and those
that cannot, for example, curbstones and
uneven ground. SICK’s integral data evaluation unit reliably detects two
classes of objects in an outdoor environment. The first class consists of
smaller objects than those that make up the second class. Wide objects, such as
walls, do not fall into the second class and are ignored for the purposes of this class. Configuring the
system only to warn the driver about objects in class 2 is an ideal
solution for narrow entrances or exits,
for example, as it will prevent unnecessary and irritating warning signals from
being issued.

The flexible configuration of
alarm zones also makes it possible to distinguish between different types of
warnings so that the driver can respond accordingly. This means that the Visionary-B system will not send faulty alarms.
The driver is only notified if the
situation is genuinely critical.

In addition to evaluating and
classifying the objects that are detected, Visionary-B has a modular concept
that enables the driver assistance system to be designed to suit the vehicle
and the purpose it is usedfor. A range of
different system configurations is available. These include variants with one
sensor head for monitoring the direction the vehicle is travelling in, with two automatically alternating sensor heads for
forward and backward movement and with two sensor heads operating
simultaneously that cover the area around and behind particularly large and
bulky vehicles.

Designed for high availability in tough outdoor environments

The Visionary-B driver
assistance system is highly rugged and is
designed for outdoor use in the many different types of environments where
mobile machines operate. The sensor housing has an IP69K enclosure rating and
can withstand operating temperatures between -40 ¡C and +75 ¡C. It
also meets high standards of shock and vibration resistance. The evaluation
unit, which can often be installed in the
safer setting of the driver’s cab, has an IP67 enclosure rating and a
temperature range of -20 ¡C to +40 ¡C. It has also been designed for long service life and can withstand challenging
conditions. The evaluation unit uses algorithms that have been tested in
practice to ensure that direct sunlight, rain, road surfaces that are damp and
shiny and other environmental influences do not prevent the unit from detecting
objects reliably or the system from issuing collision warnings.

Mobile machines offer a wide range of possible applications

The different types of mobile
machines provide a variety of interesting applications for the Visionary-B
outdoor driver assistance system. For example, the version of Visionary-B with
two alternating sensor heads can be used in excavators to monitor the area
behind the machine and the area to the side where the excavator’s arm blocks the driver’s view. Front loaders, dump
trucks and rollers are typical examples of construction and mining machines
that can be operated much more safely using SICK’s active driver assistance
system. In all types of environmental and light conditions, it can monitor
areas in the machine’s direction of travel that are not visible to the driver. This reduces the risk of collisions and
accidents to a minimum and also helps to prevent damage to the vehicle,
together with the accompanying downtime and costly repairs. Visionary-B is also
a valuable addition to agricultural and forestry machines. It can detect
possible hazards and accidents in good time and send an active warning to the
driver. A reduction in the damage caused to vehicles also means shorter
downtimes and high levels of availability, particularly during crucial times of
the year, such as harvest. In municipal
and special vehicles, for example, the
trucks used for collecting recycled materials, Visionary-B constantly monitors
the driver’s blind spot and provides active support when the vehicle is manoeuvring.

In addition to these examples,
there are many other possible applications for this advanced driver assistance
system. Visionary-B can be installed at
any time in existing vehicle models. All the
variants can be fitted by the manufacturer in new vehicles. They are
also available as complete solutions for retrofitting or as dealer accessories
and can easily be configured.

Written by:

Manuel Fischer, Strategic
Industry Manager Mobile Machines, SICK AG, Waldkirch

Dr. Anatoly Sherman, Head of Product Management 3D
Compact Systems, SICK AG, Waldkirch

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