TTP
TTP is a leading low-cost communication protocol fulfilling
the requirements of hard real-time systems. It provides
hard real-time message delivery with minimal jitter; moreover,
a variety of fault tolerance strategies is supported. It
guarantees that no single failure of any part of the communication
systemwill disrupt communication.
Fault tolerance is an integral component of the protocol
design, based on the "Single Fault Hypothesis"
and on the fully deterministic communication behavior of
all nodes.
| TTP communication controllers have been
available since 1998. Qualified third-generation silicon,
supporting communication speeds of up to 25 Mbit/s,
is available today. This high speed is coupled with
net data efficiencies of up to 80%. |
|
TTP in Off-Highway
In the last years automation and set-up aspects have carried
on developments and have resulted in reduced manufacturing
costs and in essentially higher capability of working process.
Examples are anti-roll-over systems, anti-collision systems,
auto guidance , precision farming, virtual tow bar, tracking
systems, contouring control systems, damping systems and
master-slave systems for control and safety of single or
several machines.
In fact, by comprehensive implementation of such technologies
strongly complex structures arise. While the machine operator
is responsible for safety and control of the machine up
to now, in modern mobile machines with automated functions
the onboard computer has to execute all safety and control
tasks. This results to very complex and fault-susceptible
electronic and software structures.
Off-highway vehicles get more and more connected and are
more and more intelligent. A higher complexitiy needs a
reliable data communication platform which is clearly fulfilled
by a TTP-based architecture.
Steer-by-Wire Working Group
Together with Sauer-Danfoss TTTech/TTControl has initiated
a steer-by-wire working group with about 20 off-highway
manufacturers, suppliers and organizations. This working
group is driven by TTA-Group, a cross-industry consortium
for highly dependable time-triggered systems.
The mission of the working group is to define a certifiable
reference architecture for a complete steer-by-wire application
without mechanical backup for on-road use.
This includes a selection of norms and legislations to
be compliant with, the derivation of functional and safety
requirements and guidelines together with experts of involved
companies, the work on concrete implementation of an architecture
and the generation of a technical template.
The German TÜV organizations (mainly TÜV Nord)
are involved in the process from the beginning. The concept
should be approved by the TÜV.
A cooperation in this area will result in higher cost efficiency
for suppliers and manufacturers.
The advantages of a steer-by-wire system are several and
are also related to the application: Easier layout of the
vehicle, easier installation of the steering system, improved
installation flexibility (it doesn't matter where the driving
commands are, only wires link them with the control unit,
so the commands can be double or moveable), high on field
flexibility (the steering can be parametrised according
to the field conditions and the steering behaviour can change
according to the vehicle state), easier automation of steering
function (eg. automatic guided vehicles), the reduction
of vibration inside the cabin through elimination of the
hydraulic parts.
For more Information on TTP please refer to the TTP
FAQ on the TTA-Group
website.
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