(Back to Extreme) (Decimus Lives)
last update was December 17th 2003
New shell shapes to try, what has been used - and what hasn't.
Mr Adair's rendering of an early design - a natural evolution from Maximus?
Andrew's design strengths and weaknesses
Rendering of Andrew's 'Pyramid' design
Karl's design strengths and weaknesses
Rendering of Kar'ls 'double disc' design
Decimus - the concept (made from K'Nex).
However, this did not necessarily mean that the
'Pyramid' design was going to be discarded - just not used this time.
February 2003: - The
first layout of the chassis.
This is the design brief which was sent to Aycliffe Fabrications;
"The front arms have been left deliberately long in case there are any
‘design changes’ (a daily hazard) but we are planning to fit two cuboid
‘pods’
at the front in which we will house the twin flywheels.
The other three sides will
incorporate a framework which will turn the flat sides
into triangular shapes. These will run the full length of each side – and act as
a buffer area for all the vulnerable components inside.
The section shown in
the photo is 180mm in height –
this includes the frame for the removable access ‘lid’
which you can see resting on the top.
This will mean that the rest of the shell can be fastened in place
more or less permanently, with only the top lifting off.
The main section will
be approximately 700mm in length –
‘pods’ not included, and 600mm in width.
The rear will
incorporate another upright for an axle support,
then it will triangulate backwards into the ‘buffer zone’ shape.
The wheels have moved
from the original location in the centre to the rear.
We are hoping that this will keep the wheels in contact with the ground for
longer.
If Decimus was lifted a few millimetres into the air and the wheels were
centrally mounted, contact with the floor would be lost.
However, situating them at the rear will allow the front end to be lifted
a far greater distance (i.e. when ramming something!) and wheel to ground
contact would still be maintained.
With Maximvs, we
learned a very valuable lesson –
Aluminium is a good choice of armour against blunt or wide weapons,
but not against piercing types. Conversely steel is effective
against piercing and sharp weapons, but not as good at
resisting heavy blows. In Maximvs, the combination of
stainless steel with an aluminium base was extremely effective –
it resisted blows from diamond edged axes, 30kg hammers travelling
at over 60mph and a falling cooker!
Polycarbonate armour? No thanks!"
We asked Mr Rossi of the Art Department
to think ahead,
and produce a new caricature for us.
This was the result. Mean innit?
June 2003: - Decimus under construction.
(Note Maximus in his final resting place in the background)
At this point, we are trial fitting the front spinning discs,
and the rear axle which will carry the drive wheels.
A major headache has been the belt drive
system for the spinning discs.
We wanted the discs to rotate outwards from the robot's centre, i.e. in opposite
directions.
We went through several design drafts before BS&P came to our rescue again with a
flexible belt which would twist through 180 degrees as it drove two contra-rotating
pulleys.
Rob Hughes of R H Industrial
Electronics has been hard
at work modifying Lucas (Mini starter) motors.
He has also spent considerable time designing and building
a custom speed controller for Decimus.
Many thanks Rob!
(Rob is also a fellow Rover V8 nut.
We met quite by accident one day when we
were both out in our respective Rover 3500s)
However, the power transistors we require
for this speed controller are expensive (£100.51 each).
The aquisition of these components has only been made possible by the generosity of
Tulip Computers, who have kindly donated £400 to the
Decimus project.
Many thanks to Tulip Computers and
especially Peter Maslyn;
this would not have been possible without you.
Once again, Aycliffe Fabrications have
undertaken the task of fitting Decimus' outer shell.
Decimus shared Maximus' separate chassis and shell
construction style - a successful design which withstood tremendous punishment during
'Robot Wars - Extreme'.
At this stage we are now well into October, so we are now planning ahead to 2004.
Thinking back, Maximus took two years to
complete,
so although we are behind for 2003, we are still on
track.
With Decimus' shell fitted, he weighs in
at a substantial 80kg!
Although this is under the Robot Wars' weight limit
of 100kg,
consider that he has no motors or battieries fitted
yet!
The solution? Perforate the shell with holes to lighten it.
(Picture of Andrew working taken by night
vision camera.
He has never been seen working during daylight)
Max was allowed off his wall for the Open
Evening
- once again he attracted a great deal of interest,
and provided a good contrast to Decimus' lower, squarer shape.
The new holes can be seen along the side of Decimus.
The axle mounts, made of plate steel, provided the opportunity to lose some weight.
The sides of four of the eight mounts (as seen above)were removed, saving 1.5kg.
But even more would have to be cut away from these components
without significantly weakening them.
So more material was removed by cutting
out the centres
and adding extra holes, saving in excess of 4kg.
As Christmas 2003 approaches, possible
team changes are on the cards.
The Team Captain (Andy Bannerman) is leaving St. John's to work elsewhere,
and some decisions have to be made.
In the meantime, the electronics for the
Robots drive system has been completed
in Mark One format, and is turning the Lucas starter motors with a vengance.
End of this page.
