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There are various problems associated with road
transport. Among these problems are road accidents caused by
human-related factors, such as tiredness, loss of control, a slow
reaction time, limited field of view, insufficient maintenance of
distance between vehicles, and inattention to traffic signs. A further
transport-related problem is that of loss of time which may be caused by
slow driving speed due to weather conditions, road conditions,
visibility, and traffic congestion, for example. Unfamiliarity with the
route may also cause a loss of time.
Apart from the inconvenience which may be caused
by any of the above factors, these factors also represent a huge economic
burden on developed society. If for these reasons alone, it would be
desirable to provide an automated traffic system which substantially
reduced the above problems.
During recent years the development of automated
traffic systems has received increased attention, and substantial effort
has been invested in trying to find a solution to problems such as those
outlined above.
Two articles, entitled 'The Intelligent
Vehicle-Highway Systems Program in the United States' and 'RTI/IVHS on
European Highways' appear in the ITE 1993 Compendium of Technical Papers.
These articles give a general overview of programs that are being
developed and the aims of these programs, in the United States and
Europe.
These programs, which relate to IVHS (intelligent
vehicle-highway systems), are concerned with a wide range of different
aspects of automation, such as, automatic vehicle identification for
purposes of automatic tolling on toll roads; relaying of up-to-date
information to drivers in order to improve their decision-making ability;
and automatic driving systems. Among various systems that have been
developed are the following:
satellite-based vehicle navigation systems;
traffic management systems based on a local and
international integrated sensing and communications systems for passing
information to drivers on road and traffic conditions, and for
controlling traffic lights and electronic signs;
two-way communications systems with drivers via
radio beacons and transponders located by the side of the road or beneath
it - these systems can automatically identify vehicles and broadcast
thereto a wide range of different types of information, such as
navigational instructions, traffic conditions, and the like; and
automatic driving based on an on-board
computerized control system, and on radio connection between vehicles and
sensing devices for measurement of the inter-vehicle distance, wherein
travel is carried out in 'platoons', wherein each platoon has
predetermined travel and communication procedures. Platoon- oriented
systems are described in a paper entitled 'Sketch of an IVHS Systems
Architecture', published by the Institute of Transportation Studies of
the University of California, Berkeley.
While each system has its advantages and
disadvantages, none of the systems known to the present Applicant
constitutes a comprehensive answer to the problems outlined above.
An indication of the state of the art is provided
by published PCT application no. PCT/US91/08892, publication no. WO
92/09941, entitled "Downward Compatible AGV System and Methods." This
publication discloses an automated guided vehicle (AGV) control system
which is downward compatible with existing guidewire systems providing
both guidewire navigation and communication and guidance and wireless
communication between a central controller and each vehicle, Autonomous
vehicle navigation comprises travel over paths marked by update markers
which may be spaced well apart, such as 50 feet (about 16 m).
Redundant measurement capability comprising
inputs from linear travel encoders from the vehicle's drive wheels,
position measurements from update markers, and bearing measurements from
a novel angular sensing apparatus, in combination with the use of a
Kalman filter, allows correction for navigation and guidance errors
caused by such factors as angular rate sensor drift, wear, temperature
changes, aging, and early miscalibration during vehicle operation. The
control system comprises high frequency two-way data transmission and
reception capability over the guidewires and via wireless communications.
The same data rates and message formats are used in both communications
systems.
The above-outlined system is intended for
purpose-built vehicles used in a warehouse situation. Accordingly, while
addressing certain points of automated control of vehicles, it does not
provide a solution to the various transport related problems discussed
herein.
The following patent publications are also known:
EP482424, EP229669, WO8200122 and EP367527. These publications describe
systems that are intended for controlling vehicles in limited, defined
areas, such as on factory floors, in the area of production lines,
warehouses and the like. These systems include several dozen vehicles
that travel in predetermined fashion along fixed routes, with fixed
stopping places or stations, and which travel over a distance of between
several dozen meters and several kilometers.
The operating principles of the systems described
in above four documents do not permit management of a transport system on
a large, substantially unlimited scale. The main reason for this, common
to all these systems, is the fact that each system employs a vehicle
communications and control system which employs a single central computer
which manages all of the users, and all of the communications. To
the best of our knowledge, no single computer exists which is capable of
handling the tasks of continuous, real-time vehicle control, in a
transport system encompassing possibly many millions of vehicles. It is
thus apparent that none of these systems is either intended or presumes
to be capable of managing a large scale transport system.
USP 4361202 describes a transport system that may
contain millions of vehicles, but it is based on a single central
computer, with its inherent drawbacks, as discussed above. Furthermore,
no continuous communications exist between this system and the vehicles
‘controlled’ thereby. System to vehicle communications are established at
commencement of a journey only, by means of a radio-telephone link to the
control center operated by a vehicle driver, so as to receive details of
a recommended route, including driving directions that are recorded in
the memory of a computer in the vehicle. Subsequently, unless the driver
initiates further communication with the control center, no
communications occur until the end of the journey. The vehicle drives
itself in accordance with the route plan stored in its computer memory,
and, further, in accordance with information provided by transponders
along the route that provide to the vehicle information concerning the
conditions and physical parameters at the transponder locations, rather
than information particular to any specific vehicle traveling therepast.
This operating principle is based on the
assumption that no changes will occur (or be required) and that the
transport system will behave in practice exactly as planned - an
assumption which, it is submitted, is totally inconsistent with modern
driving conditions.
This system employs feedback from magnetometers
or radar for detection of the speed and type of vehicles traveling along
different routes. The system is not provided with any feedback in terms
of the location of any particular vehicle or in terms of its
mechanical/safety state, and is thus incapable of controlling vehicles
individually, relating to vehicles as part of a mass only. Accordingly,
it does not provide continuous and real time control of any specific
vehicle.
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