vehicle; their second part established rules for deployment,
operating, and transporting the ALIEN ROV.
“The main part of the vehicle’s systems is an electronic
unit. Like a human heart, it drives all other units and systems
to precisely perform the orders of the pilot,” the team
notes.Control signals to the electronics components are
passed through the controller board which is based on an
microcontroller. It controls pressure sensors (Honeywell
ASDX015A24R-DO, and SensorsOne DMP 331;
www.sensorsone.co.uk), a SparkFun electronic compass
(HMC6352), a CRS accelerometer, and a manipulator control
board; it also controls voltage to the decoder of a
multiplexer. A video multiplexer receives signals from the four
available cameras to transfer all video streams to the surface,
where a demultiplexer provides the desired video stream to
the operator’s monitor. A power board supplies all the
electronics components with necessary voltage (24V, 12V,
5V). Also, the microcontroller board supplies 3.3V that is
necessary for some of the components.
Cameras and Lights
the electronics unit and the switching block. For video
transmission, the team used two 1.5 mm coaxial cables with
an impedance of 75 ohms. The ROV requires rather high
power, so they chose two 6 mm power cables. To transmit
control signals, a twisted pair cable is used.
To collect all the wires in one tether, the team creatively
bought a rubber garden hose which was used as a sheath.
Broaching wire in the hose is very laborious, but rather
exciting work. They ended the process of broaching at the
top of a five-story building, stretching the tether to the entire
height of the building and straightening all the wires inside.
The commutation unit is used to separate the tether into
different lines: power, control, and video.
The 48V from a power supply comes to the
commutation unit through the fuse which protects the circuit
against excess current. The power is then supplied to the
board of power switches and after that, to the ROV. The
video signal passes through the video modulator and then
appears as part of the GUI on the laptop screen. Control
signals are transmitted between the operator console on the
surface and the electronic unit onboard via an Ethernet
interface. An AC/DC converter was integrated to the
commutation unit to power the vehicle from AC power.
ALIEN uses VM32HQ-B36 modular color cameras from
Video Security (
www.videosecurity.ru). They chose these
due to their small size, ease of installation, high sensitivity
(0.1 lx), and availability. Among the other advantages of the
camera is backlight compensation — which is useful for
underwater observing — because the observed objects will
be placed on a background of bright light.
The basis of lights is a SibProekt “Photon” MR-0209
http://sibopt.ru) which has nine LEDs in a
waterproof housing. An unnecessary container for batteries
was removed since the lights are connected to the control
board power supply.
The data cable is designed to transmit signals between
Primorye Coast stuck with open source software.
Selecting the most up-to-date open source development tools
and free operating system, they built the control board on
Ubuntu OS using the Qt Source Development Kit and open
source libraries. All communications with the ROV are made
through the Ethernet interface that is compatible with Linux
OS. Also, Ethernet was the most appropriate solution with
42 SERVO 09.2012