INDEPENDENT WING CONTROL
Having
solar panels give you virtually free energy is great but the only draw
back is that it’s got to be sunny and the solar panels must point
towards the sun. But hang on a moment, our ship is not always going to be
aligned with the sun. So, we need to make
the ship capable of aligning it's solar panels to the sun for optimum
collection, regardless of the direction the boat is going.
Photoresistor comparator test circuit
How can this be
done? We need some way of “seeing” where the sun is, then
using that information to tell the panels where to point. Ideally,
this should be achieved automatically to free the crew and ensure
accuracy. Fortunately, thanks to electronics there are many different ways in which
to measure light, or sunlight - usually by a photo reactive sensor, or
photocell. Provided we set up a suitable photocell such that it
detects direction, we could then tell where the sun is. But only a
few sensors are reliable and rugged enough to be put on a
ship that is going to be exposed to a harsh marine environment.
So,
now that we can see where the sun is we need to be able to use this
information to move the solar panels. Obviously, we need a motor
drive to move the panels. For simplicity we are going to use a
radio control type digital proportional servo. But hang about,
doesn't that use lots of power and we don’t want to be wasting
power which we could be using to drive the boat. So we need to make sure we are going to
move the solar panels in the right direction first time. To be
sure we achieve this we will use dual sensors on each side of the ship, plus there will a
scanning sensor mounted on the bridge of the ship.
All
this data that we can get from the sensors is great but what do we do
with it all. Well, to start with we need to process the data first as the
signals will be coming in various forms i.e. Digital and analogue.
Once
this data is in side the control systems we can do some dare I say it
mathematics. This is were it all start getting rather complicated.
RISK Processor
The
control system needs to be able process millions of signals every second
and determine what action it should take. To make things run even faster
we are going to implement mutli processor functions. Meaning that we
will have several computers control systems to process the signals.
For
all this computing power we will be using PICs from Microchip.
These
are small yet highly powerful devices. PICs are available with
loads of onboard hardware functions such as USART PWM capture and so on.
I know it's all getting a bit technical, but sometimes you have to
knuckle down to get things done. If the term are a bit
worrying, ignore the details for now - jus
A
control system that can do all the calculations we want (work) is great, but sometimes your
going to get conditions that you just don’t expect. So it must have
some form of override. All the control systems are fitted with serial
ports and can all talk to each other, like one fax machine to another, but should we need to take control
we can log into the system and administrate the control of the solar
panels.
WATCH THIS SPACE AS THE PROJECT DEVELOPS TO A FULL BLOWN WORKING PROTOTYPE
COMPONENTS:
Light
sensor: LDR
Sensor
processor: microchip PIC comparator
Maths
processor: microchip PIC
Serial
port override: handheld device or laptop
Actuator
drive: independently controlled by microchip PIC
Actuator feedback sensor: processed by microchip PIC
OUR ELECTRONICS DESIGNER CONTROL ELECTRONICS SOLAR WINGS
|