

File: Description_Kemmel_Track_R02.txt
R01 - 2011 Mar 26 - hdrake - TabbyCat Robots
R02 - 2011 Apr 07 - hdrake - TabbyCat Robots


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Here is a description of my Spa racetrack for NXT line following robots.

A robot can follow a simple loop around the whole track.  It will have long
straghts and some twisty parts.
There will be some colored markers on the track, that will indicate passing
lanes, and pit areas, and the robot can react to these.

The lines to be followed are black and the track is white.

There are colored markers on the track that act as instructions to the
robots.

The main feature of the track is a straightaway approx. 18 ft. long.

The track is 30 in. wide, and 3 lanes wide in some areas.

The lanes are 10 in. wide.

In areas with 3 lanes, the black lines are laid out such that the
left side of the lines are 5 in., 15 in, and 25 in. from the left side
of the track.

The black lines are approx. 15/16 in. wide, except on the long straight
where they 2 in. wide.  This is to allow for some wobble at very
high speeds.

Lines are laid out such that the robot should follow the left side of 
the line.

The minimum radius of curves in the pit lane is 4-1/2 in.
The minimum radius of curves on the racing line is 7-1/2 in.,
with the exception of 1 or 2 curves with a 4 in radius.  These
will be preceeded by a special marker, and there will be a
straight black line, if the robot chooses to ignore the marker
and tight curve.  The straight black line will lead back onto 
the regular racing line.

There will be barriers (catch fences) on the sides of the tables
to prevent robots from falling onto the floor.   (Unless you have
an SUV robot that can scale a 5 in. high barrier.)

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Colored Road Markers
The colored road markers are stickers on the racetrack.

The markers are 2 in. wide.

The markers overlap the black line and are set in approx 1/2 in.
i.e., the left side of the marker is 1/2 in from the left side
of the black line and the right side of the marker is 2-1/2 in.
from the left side of the black line.  (Yes, the robot will probably
need 2 sensors, one to follow the black line, and one to read the
colored markers.)

As the robot travels the black line, it will see markers as follows.

(I will use the quote symbol ", for inch.)

Markers on the main racing line.
----------------------------------------------------
1" black, 2" green, 1" black - okay to accelerate - straight track
ahead.  At the start of the long straights, there will be 2 to 4 of
these green markers.  There will be red markers, (see next description),
at the end of the straight.

1" black, 2" red, 1" black - curve ahead - you'd better slow down.  The
number of red markers gives an indication of the tightness or difficulty
of the curve ahead.



1" black, 2" blue, 2" green, 1" black - additional lane to right,
okay to change lanes to right.  If preceeded by a "pit lane ahead -
1" black, 2" yellow, 2" green, 1" black", then pit lane entrance to
right.

1" black, 2" blue, 2" red, 1" black - additional lane to left,
okay to change lanes to left.  If preceeded by a "pit lane ahead -
1" black, 2" yellow, 2" green, 1" black", then pit lane entrance to
left.

1" black, 2" blue, 2" yellow, 1" black - located on a curve -additional
lane by leaving line and going straight.  If preceeded by a "pit lane
ahead - 1" black, 2" yellow, 2" green, 1" black", then enter pit lane
by going straight.



Parallel to the Start-Finish straight, there will be a pit lane.  A
robot will be able to continue on the race line, and circulate
around the track.  Or it can react to the following marker and make
a pit stop.
1" black, 2" yellow, 2" green, 1" black - pit entrance ahead.  

1" black, 2" yellow, 2" red, 1" black - start finish line.

1" black, 2" yellow, 2" blue, 1" black - very sharp curve ahead - you'd
better slow down a lot.



Markers on the pit entrance line.
----------------------------------------------------
1" black, 2" green, 1" black - pit stalls are to the right, while proceeding
down pit lane.  Also indicates the end of pit entrance and the beginning of
pit lane.

1" black, 2" red, 1" black - pit stalls are to the right, while proceeding
down pit lane.  Also indicates the end of pit entrance and the beginning of
pit lane.



Markers on the pit lane line.
----------------------------------------------------
All robots will be assigned a color, green, red, yellow, blue.
This will identify its pit stall.

As a robot proceeds down pit lane, it will detect the following
markers.

1" black, 2" green, 1" black - pit stall for green car is to left or right.


1" black, 2" red, 1" black - pit stall for red car is to left or right.


1" black, 2" yellow, 1" black - pit stall for yellow car is to left or right.


1" black, 2" blue, 1" black - pit stall for blue car is to left or right.


1" black, 2" yellow, 2" green, 1" black - pit exit begins.  



Markers on the pit stall line.
----------------------------------------------------
1" black, 2" red, 1" black - the robot should stop and wait for button
press before proceeding.  (Note that the yellow robot may now have to
not react to 1" black, 2" yellow as its pit stall, depending on your
programming.)
When the button is pressed, the robot will move back to the pit lane black
line, and follow back onto the racing line.  By the AFOL pushing various
buttons, the robot may ignore or act on lane change color markers on the
track, or do other tricks.



Markers on the pit exit line.
----------------------------------------------------
1" black, 2" green, 1" black - okay to accelerate - prepare to merge to
main racing line.




Description of black line at lane changes and pit entance.
----------------------------------------------------------------------
When a robot detects a marker for lane change or pit entrance,
it should:
1.  Turn about 45 degrees left or right.
2.  Proceed about 4 inches across the colored marker and white space.
3.  Start looking for a black line, that will be about 1 inch to 8
    inches from the previous black line.
4.  When the bleck line is detected, start following it.  It will
    lead to the adjacent lane, or the pit lane.

When 2 black lines (lanes) merge, there may be a short space (~1/2")
without black line.



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Robot specs: (For open track time at BrickFair 2011)

Robots may be built around NXT, RCX, Spybot, or other intelligent bricks.

Maximum robot width:  8 inches
Maximum robot width with any or all caster wheels turned out: 8-1/2 inches.

Maximum robot length:  13 inches

All parts of the robot, except of course tires must clear the track by
1/4 inch, preferably 3/8 inch.

All robots must have a driver and/or passenger - minifig, technic guy,
etc.

The robot may have 1, 2, or 3 motors.

The robot can have ultrasonic or touch sensors to prevent knocking any
leading robots off track.

Wheel / Tire size is open.

Maximum vehicle height is 8-1/2 inches.

Robots may have one or two intelligent bricks.

Robots may have most of the intelligence for controlling the robot
residing in the programs on board the robot.

Or the robot may take some instructions from remote controls, cell
phones, laptops, etc.

1.  When the robot is stopped in its pit stall, the pit crew can
reprogram the NXT, change tires size, etc.  Anything you can do
in 15? 20? seconds.  Otherwise, move the robot to the garage area,
and let another AFOL run her robot. 
2.  When doing wobbly line following and simulating texting while driving,
minifigs on 2 robots can use the blue tooth connection - lots of imagination
required to program this.

Robots can have any number of forward and/or reverse speeds, but the
track is designed for 6 speeds.  And remember that a robot's speed is
related to motor power, gearing, and tire diameter.

Ideas for speeds from slowest to fastest:

Pit lane - use in pit lane  e.g. 20% power.

Slow curve - for 4 inch radius curves  e.g. 30% power.

Standard - for short straights and sweeping curves  e.g. 40% power.

Straight Line - a little faster  e.g. 50% power.

Very Fast - Yes!  e.g. 60% power.

Max Speed - Now the fun begins!!!  e.g. 70% - 100% power.



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References
----------
I firmly believe in Isaac Newton's quote:
"If I have seen further it is only by standing on the shoulders of giants."
or "Give credit where credit's due."

My NXC line following code is from ideas in the NXT-G program LineFollowPro,
at http://www.nxtprograms.com/line_follower.
I could not find an author's name.

Lego Mindstorms NXT Power Programming
Robotics In C
Second Edition
John C. Hansen

Creating Cool Mindstorms NXT Robots
Daniele Benedettelli

An Introduction to ANSI C on Unix
Paul S. Wang

NXC Programmers Guide
June 8, 2010
by John Hansen
NXC
Version 1.2.1 r3

Programming LEGO NXT Robots using NXC
(beta 30 or higher)
(Version 2.2, June 7, 2007)
by Daniele Benedettelli
with revisions by John Hansen

The Lego Mindstorms NXT 2.0 Discovery Book
Laurens Valk


 