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electronic starting was implemented             It is also interfaced to several sensors  for any UGV is the automatic detection
using a series of relays to replicate the   for vehicle health monitoring and control     of obstacles on the path. For this project,
starter key positions. The accelerator      such as engine temperature sensor,            the obstacle detection is implemented by
control was implemented within the          ambient temperature sensor, fuel level        two sets of ultrasonic sensors mounted on
engine compartment using a stepper          sensor, etc. Warnings are issued to the       both the front and back of the UGV.
motor to directly actuate the throttle      base station operator whenever the engine
lever. Braking of the vehicle is done when  temperature exceeds safe limit or when            They are suitably angled to cover the
both the steering levers are pulled back    fuel level drops below recommended            entire width of the vehicle. If an obstacle
simultaneously.                             level. The perception system consists of      is sensed by the obstacle detection sensors
                                            two dome cameras, one in the front and        within three metre during teleoperation,
Tele-operation Sub-system                   one in the rear of the UGV.                   a full brake command is automatically
                                                                                          generated by the controller and the UGV
    Tele-operation is defined as the mode       Both the cameras have pan, tilt,          is brought to an immediate stop.
of navigating a UGV through wireless        zoom facilities, so that a satisfactory
communication links, assisted only by       tele-presence effect can be given to the          The obstacles are also displayed on an
the visual feedback received from the       base station operator. For localisation,      obstacle map at the base station for the
UGV. The controller hardware consists of    a GPS with 5 Hz update rate and 15 m          information of the operator. The power
a PC 104 based 800 MHz controller, with     (CEP) is used. One major requirement          supply consists of two lead acid batteries.
adequate Input-Output(IO) and ethernet
port for control and data. It receives the  Salient Features of the Drive-by-Wire System
commands from the base station and
actuates the required driving controls of   Accelerator  Stepper motor based drive actuator of throttle lever
the UGV.                                    Steering     Stepper motor/cable based actuation of the two steering levers
                                            Brake        Stepper motor/cable based actuation of the two steering levers
                                            Gear shift   Stepper motor/mechanical link based actuation of the gear link

                                            The DBW system of the teleoperated ATV

Unmanned Ground Vehicles: Present and Future								March-April 2018                                                     5
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