Collision avoidance and navigation support in the warehouse

Collision avoidance and navigation support in the
warehouse

Modern electric
lifting trucks, order pickers, tugs, and mobile transport platforms provide
users with additional potential benefits thanks to the option of
semi-autonomous operation. As well as ensuring that vehicles make
collision-free journeys, 2D LiDAR sensors from SICK’s TiM series also deliver precise measurement data for navigation
purposes. What’s more, a 2D LiDAR sensor with performance level b is now
available for the first time to cater to safety-related applications.

In many intralogistics systems,
a trend toward smaller and more flexible transport and picking vehicles can be identified. The reason for this is that it
is often easier for these vehicles to adapt their transport capacities to daily
fluctuations and seasonal peaks as well as to changes in order and customer
structures. To enable them to operate autonomously – be it individually or in a
network – they need to be protected against collisions intelligently and equipped with the option to navigate for themselves.
This is all because the vehicles need to
be able to find their way through the halls by themselves and have to be able
to deal with virtually any kind of obstacle that may come their way.

TiM 2D LiDAR sensors satisfy requirements for integration
capability and availability

The various TiM product families from SICK offer
application-oriented solutions here as, first and foremost, they meet key
device-related requirements. The compact TiM5xx, for example, which is used for simultaneous object detection,
position detection, and navigation, has an overall height of just 86 millimetres, making it easy to integrate even
in confined installation spaces. Their low weight and power consumption also
play an important role, particularly in
mobile applications. The TiM1xx weighs just 90 grams and requires just
2.2 W of power. Its energy efficiency and compact design satisfy the
highest requirements regarding
functionality and mobility, as well as the desire for long, interruption-free
operating times for the vehicles. TiM
sensors also impress thanks to their well-thought-out industrial design, which
considers shock and vibration resistance as well as ambient light immunity. Also, they are
designed for quick and simple plug & play integration, which is an
important factor in terms of ensuring the
availability of autonomous, intralogistics vehicles in the event that the sensors need replacing.

The next requirement concerns
the sensor technology itself. Above all else, the technology must not pose any
risk or hazard to the people present in the operating environment. What’s more,
detection capability must be designed so
that different materials, surface structures, and colours are detected to the same degree of reliability –
irrespective of influences from the operating environment such as dazzling
sunlight or darkness. The sensors’
resolution has to be so fine that mobile obstacles in particular – objects and
people – are reliably detected in addition to stationary hall elements. Thanks
to their innovative HDDM technology, all 2D LiDAR product families also satisfy
the highest requirements in terms of
detection accuracy.

TiM361S: the smallest safety-related 2D LiDAR sensor

In mobile applications such as
collision avoidance on service robots and mobile platforms as well as in
stationary tasks such as access control on pick & place robots, risk
analyses in many cases find that protection in
accordance with performance level b is the most efficient solution from
a technical and economical point of view. For industrial applications of this
nature, the TiM361S is the first safety-certified 2D LiDAR sensor to be
available with performance level b in accordance
with EN ISO 13849-1:2015. In the safe working range from 0.05 cm to
4 m, up to 48 independent monitoring fields and as many monitoring
scenarios and protective field geometries as required can be set up. The
TiM361S represents the perfect union between measurement performance and
functional safety and fits seamlessly into SICK’s existing 2D LiDAR product
portfolio.

Route monitoring for semi-autonomous industrial trucks

With the integration of two
TiM3xx area sensors in one order picker, it is possible to perform autonomous
transport tasks without the risk of collisions. When the forklift element picks
up the load, a TiM3xx detects the position of a pallet, for example. The sensor
doesn’t just detect a possible obstacle
between a vehicle and pallet – it can also assist the vehicle control when
lifting a pallet. During transportation, a front-mounted TiM monitors the route – at an angle of 270¡
and in a working range of up to ten meters. A whole host of monitoring
scenarios can be stored in the sensor for
such purposes. 16 pre-configured triple fieldsets
are available in the form of a message,
warning, and stopping fields, whose shapes can be
defined as rectangular, radial, or as free geometries. The configuration
of a fieldset can be adjusted directly at
the sensor so that special requirements from the application can be implemented
directly on site. To prevent the risk of
unintended sensor misalignment, various device versions have “contour as
reference” functionality, which allows these LiDAR sensors to monitor for
correct alignment themselves. If, in addition to route monitoring, the
operating environment is also to be recorded
for navigation purposes, the TiM5xx product family delivers the measurement
data needed for this.

Position detection and destination navigation for self-driving platforms

These navigation functions also
come into play when used on autonomous mobile robots, which pick items by
themselves and then set off for the various warehouse aisles and picking areas
independently. With its working range of up to 25 meters, the TiM5xx LiDAR
sensor provides both order pickers and self-driving robots with the necessary
range of vision to avoid collisions and to collect navigation-related
information from the operating environment. With a possible resolution of 0.33¡
within a scanning field of 270¡, the TiM571 provides highly accurate
measurement data from the scanned surface. This
enables even very small obstacles and orientation marks to be detected and
their distances to be determined. The measurement data itself is output via USB
or Ethernet interface in the form of a machine-readable string and processed
further in the higher-level applications of the vehicle control. As a rule, a
single TiM571 will generally be
sufficient for both order pickers and mobile platforms, as the pickers have a
preferred direction of travel and the platforms generally
rotate on the spot to enable them to travel in the required direction.

TiM supports autonomous mobility

Autonomous-mobile intralogistics
requires intelligent sensors which deliver real-time information to
self-driving vehicles and platforms regarding their environment. The 2D LiDAR
sensors in the TiM series offer the
necessary precision, reliability, and speed to reliably avoid collisions and to
provide effective support to higher-level systems used for navigation and
position determination purposes.

HDDM scanning technology:
improved detection, improved navigation

The 2D LiDAR sensors (Light
Detection and Ranging) of the TiM product families use eye-safe infrared light
(laser class 1) and the HDDM technology (High Definition Distance Measurement)
developed and patented by SICK. The latter is a high-resolution digital process
for measuring time and distance, which sends out around 100 times more laser
pulses than other time-of-flight measurement systems in the same period. The
short sequence of pulses and the low angular resolution in the scan plane of up
to 0.33¡ provided by the TiM3xx and TiM5xx guarantee an uninterrupted scan and
reliable detection and measurement functions. The HDDM measurement process also
provides very high optical reliability. Thanks to this high ambient light
immunity, it is almost impossible for the TiM sensors to be dazzled either by
bright daylight or by high-frequency artificial ambient lighting, as is typical
in an intralogistics environment. The measurement process can also compensate
for the effects of dust, dirt, and moisture in the environment.

TiM100 – the entry-level sensor
family for 2D detection

A field, an aperture angle of
200¡, a working range of up to three meters, and a switching output for field
evaluation – the TiM100 is the entry-level series in 2D surface monitoring. Yet
despite being an entry-level model, this LiDAR sensor has a lot of offer –
including IO-Link for simplified commissioning and diagnostics, as well as the
more advanced HDDM+ process, which has enhanced the reliability of this
millimetre-precision detection process even further. Intralogistics
applications such as empty bay detection in pallet and container warehouses or
protrusion monitoring for mesh boxes are also able to benefit from this.

Written by: Christoph Hirt and Jonas Ledergerber,
both Product Managers for the TiM series
at the Global Business Center Identification & Measuring, SICK AG, Reute, Germany

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