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On Thu, 30 Sep 1999 23:54:48 -0400, you wrote:
> Hello Ian,
> When will we see something from you? You're a Technic fan I believe aren't
> you? Or am I mistaken?
I have been a passionate Tehnic builder for about a year now...
Mindstorms caused it of course... :-)
I am finishing the complete rebuild of my 8448 Street Sensation Gull
Wing for the show next weekend. It will have the following when stage
five of the rebuild is complete:
- Four drive motors with their own battery box, and a micromotor
polarity switch for controlling this independent circuit. I have now
installed the four motors, and polarity switch, but have yet to do a
chassis rebuilt to incorporate the battery box in a more satisfactory
manner. I may adjust the RCX's position in the trunk to place the
battery box under or behind, or beside it.
- One motor and rotational sensor for centering and steering the front
wheels. Now installed.
- Some method (probably micromotors) to shift the transmission while
car is in motion. I am designing this system now. It has been the
most difficult problem to solve. I want to keep the gate shifter as
it comes in the original, but shifting it through those gates using a
control system is proving problematic. If I have too, I will remove
the gate shifter completely, and control the position of the gears
directly with my control system. This method should be easily solved,
but I would like to keep the shifter if I can. I might solve the
problem with pneumatics, but then I have the problem of controlling
the valves with the RCX. As none of the AFOL, including myself, have
come up with a good way to do this, I think this method is unlikely.
- When the 8448 rebuild is complete, I will demonstrate the car under
IR remote control. If I have time this week to finish the programming
I will finish adding the light sensor and touch sensors to the bumpers
after their overhaul.
It is my plan to race my 8448 against other member's rebuild of their
own 8448 or 8880. We cannot both use the LEGO IR Remote Control so
the next step will be the creation of a large road course.
I will probably use black electrical tape (or similar) to mark out the
centre lines of multiple side-by-side tracks. These tracks will
follow the same course, crossing paths at different locations around
the track to ensure each tape line is the same length. It will also
make for some spectacular collisions in really close races!
I hope the course will have both wide and sharp curves, hair pin turns
and shicanes (sp?). Races will be multiple laps as car design and
more advanced programming techniques get developed over the next few
months.
Designing, testing and choosing the best method and strategies for
programming our different designs should lead to several approaches
being taken by different designers.
Some will choose to go slowly, following the tape path with little
problem. Others will go faster, running the risk of blowing a turn
and going off the course. The car will have to be programmed to
handle such an event.
This will prove really interesting and quite funny I'm sure.
Of course, I plan to go as fast as my design and programming skills
permit. <grin>
Using a fast steering design and one, possibly two light sensors, I
will track the cars position on the tape and constantly adjust the
steering to keep the nose centerline over the tape.
My car will accelerate, shifting gears as programmed.
If the car blows a tight turn because of its high rate of speed, the
program will immediately shut down the motors and center the steering.
It will then back straight up till it crosses a tape trace. It will
then attempt to steer itself back onto the course and continue.
If the car backs up farther than it thinks it should have, it'll turn
sharply in the direction it was turning when the track was lost and
move forward till a trace is found. I may widen the search radius
after a period of time. Eventually, it will find some part of the
course.
Cars leaving the track will cause interesting and funny moments. Some
may never find the track again! Others may get screwed up or turned
around and end up going the wrong way down the track.
And lastly some may be on the inside traces when they loose the
course, and back up to find one of the outside traces. If it gets
moving again, we'll end up with multiple cars on the same trace. This
could lead to still more collisions, and as Tom Cruise would say,
`Rubbing is Racing!'
I have a few more ideas for really advanced programming I prefer to
keep secret till I've one a few events. :-)
The rules haven't been finalized yet, but I'm sure you will be able to
follow any trace you end up on without penalties. I think we'll
divide the track into 10' blocks or some other number. Lap counters
will count the number of blocks each car successfully drives.
So many laps or so many blocks driven will constitute a race.
Maybe we'll increase or decrease your block count during the race
depending on how well your car drives the course. We could subtract
(x) blocks for leaving the track, add (x+y) blocks for getting back on
the track, wrong trace, add (x +2y) blocks for getting back on the
original trace. Subtract (x) for returning to the wrong place on the
track. Add (x) for returning the track where you left it.
And whatever other rules of engagement we like. How about getting
(10x) for running another car off the course in a shicane!
I hope these race events are a great deal of fun for builders,
programmers, and spectators alike.
I'll keep you informed...
Ian Sinclair
Calgary LEGO Robotics Group
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