The
robot must not be constructed in such a way as to damage the
environment or other robots. See "Safety" for other restrictions. No
robot may weigh more than 50 pounds nor may it use an internal or
external combustion engine. The robot must fit inside a 4' x 4' x 4'
cube for the entire duration of its run.
Robots must be autonomous. Remote control is not allowed, with the
exception of the remote control safety switch.
Course
The
course will be outdoors with both natural and manmade terrain and
obstacles. The terrain may include pavement, dirt, small rocks, grass,
hills, gullies, trees, curbs and weeds. This list is not exhaustive.
The robot will not need to traverse a water obstacle to complete the
course although weather conditions may make some surfaces wet and/or
soggy. The contest will not necessarily be postponed in the event of
inclement weather.
Robots will be placed at a designated
starting point prior to each run. The destination and bonus waypoints
will be designated with latitude/longitude coordinates and marked by
18", orange, plastic traffic cones. Waypoints will be specified as
degrees and minutes with minutes carried out to four positions right of
the decimal point (N 47 22.1245 W 122 32.0493). The datum is WGS84.
The
total straight-line distance between the start and destination will be
less than 1,000 feet however the shortest route may be longer due to
obstacles. The route taken from start to destination, including bonus
waypoints, may be significantly longer than 1,000 feet.
Play
The
latitude and longitude of the start, destination and bonus waypoints
will be announced at the start of the contest along with other
considerations such as safety matters and course boundaries. Mandatory
bonus waypoints and order, if any, will also be announced. The number
of mandatory waypoints, whether or not there will be a specific order,
etc. will not normally be announced in advance of the actual contest.
Contestants will then have 30 minutes to make software and hardware
modifications to their robots. At the end of 30 minutes, a judge will
signal the start of the race. Each robot will be given three chances to
complete the course and 30 minutes will be provided between attempts
for software and hardware modifications.
During the initial
30 minutes between the announcement of the course and the start of the
contest, contestants will be able to walk the course to take
measurements. Acceptable measuring instruments include a hand-held GPS,
tape measure, wheeled measuring device, etc. However, the actual robot
will not be allowed on the course. Please see Intended Rule Evolution
in the appendix for more information.
Judges will determine
the maximum number of robots that can run at once. If more than one
robot will be run simultaneously, judges will stagger the start times
to minimize the chances of robots interfering with each other. Judges
will also designate the order in which robots will start. Consideration
will be given to robot speed, intended route, safety features and other
factors when determining the starting lineup.
Each robot
will work their way toward the destination waypoint following the
course its operator deems appropriate. Boundaries will be set and, if a
robot crosses a boundary, it will be immediately stopped and no score
will be awarded for that attempt.
Robots must touch bonus
waypoint cones (but not move them or knock them over) to score bonus
points. Robots must touch the destination waypoint and stop in order to
complete the course. Robots that do not complete the course will
receive no score for that round (see exception under Scoring). Other
than GPS, robots cannot use external beacons or markers as navigation
aids, nor can robots employ devices like differential GPS to boost the
accuracy or reception of GPS signals.
Each robot is given 15
minutes to complete the course on each of its three attempts. Each
attempt is scored individually. After three attempts, the best (lowest)
score for each robot will be recorded as that robot's final score.
Thirty minutes will be given between attempts to allow for software and
hardware modifications.
Robots do not need to travel the
same route for each attempt. Contestants may try alternate routes in an
effort to improve their score or chances of finishing.
Scoring
Basically,
robots will receive a score corresponding to the number of seconds
needed to travel to the destination and any bonus waypoints. The robot
with the lowest score on any individual run will win.
Bonus
waypoints are assigned multipliers (between 0.1 and 0.9) prior to the
start of the competition and will reflect the difficulty of the
terrain, distance from the start/destination and any other factors the
judges consider relevant. The judge may specify one or more bonus
waypoints as mandatory waypoints. Robots must navigate to and touch all
mandatory bonus waypoints prior to navigating to the final destination.
The judge may optionally specify a particular order for bonus
waypoints. If an order is specified, robots must travel to bonus
waypoints in the correct order prior to navigating to the final
destination.
A robot must physically touch the orange
traffic cone marking a bonus waypoint to receive a scoring multiplier.
If a bonus cone is moved or knocked over, no bonus will be awarded for
that cone. The robot may "tip" a cone and still receive a bonus as long
as the cone doesn't move from its previous position or fall over. If a
robot successfully navigates to more than one bonus waypoint, all
applicable bonus multipliers will be applied. For example, if a robot
requires 500 seconds to complete the course and visits two bonus
waypoints with multipliers of 0.5 and 0.1, the final score for that
attempt will be 500 x 0.5 x 0.1 = 25.
If a robot does not
finish, it will receive a score indicating the distance remaining to
the target cone, along the shortest practical path to the destination
(not necessarily a straight line between the robot and the destination
cone), taking into consideration mandatory waypoints as applicable.
Robots that complete the course at least once will always place higher
than robots that do not complete the course. If no robots complete the
course, the robot that came closest to the destination cone (while
considering any mandatory bonus waypoints) will be declared the winner.
If
the course has mandatory bonus waypoints that must be touched in a
particular order, the distance to the final cone will be measured from
the robot's final position to the next untouched bonus waypoint, any
subsequent bonus waypoints (in order), then the final destination. If
waypoints are reached in some order other than that specified, any cone
that was touched out of order will not be counted for a bonus or as a
place along the course to the final destination. In other words, if a
course consists of bonus waypoints A, B and C (which must be touched in
that order) with a final destination X and the robot touches B but not
A, the distance to the final destination will be the robot's position
to A plus A to B plus B to C plus C to X and no bonus will be awarded
for touching B. If the robot touches A only then the distance to the
final cone is calculated by the distance from the robot to B plus the
distance from B to C plus C to X and a bonus will be awarded for
touching A. If the robot knocks over A then touches B, the distance to
the final destination is the robot's position to C plus C to X and a
bonus will be awarded for B but not for A.
When mandatory
bonus waypoints are specified but no particular order is given, the
robot's distance to the final destination will be calculated along the
shortest route (once again, not necessarily a straight line) between
the robot, any untouched mandatory bonus waypoints, then the final
destination. So, if a robot has traveled to B only, the distances for
robot to A to C to X and robot to C to A to X will be calculated and
the shortest distance used for scoring.
Scoring will be at the sole discretion of the judges.
Judging
One
or more judges will officiate the contest. They will ensure the spirit
of these rules are followed and impose scoring penalties or remove a
robot from competition if the robot is operating in an unsafe manner or
not complying with the spirit of these rules. The decisions of the
judges are final.
Safety
Each robot must demonstrate a suitable fail-safe stop mechanism before
it will be allowed to compete.
Suitable
safety stop mechanism:
The robot builder is responsible for devising the safety stop
mechanism. Some possibilities include:
* Wired tether operated by the handler
walking alongside the robot
* Some wireless contrivance operated by
the handler
* Some other mechanism, with prior
permission from the SRS.
In
any case the safety stop switch must be fail-safe: The robot handler
must demonstrate that by dropping, or letting go of the stop mechanism
the robot comes to an immediate stop and makes no further movement. The
stop mechanism does not need to cut primary power as long as it can be
demonstrated that the robot reliably comes to a complete halt.
The
safety stop mechanism may be built to allow the robot to continue its
run after it is reengaged. The intent of this feature is to stop the
robot and allow it to continue if, for example, a small child runs in
front of the robot op the robot completely to prevent damage to itself
or the environment. The safety switch will not be used to stop the
robot in order to reposition the robot or remove an obstacle like a
garbage can from the robot's path. If the robot is stopped temporarily,
it may continue and the time during which the robot was paused will be
subtracted from the final score. In other words, there is no time
penalty for stopping the robot due to safety concerns.
No other "remote" control beyond the safety stop is allowed.
Liability
Each
contestant is fully responsible for any damage to person or property
caused directly or indirectly by his or her robot. The Seattle Robotics
Association, including the Seattle Robotics Society, is not responsible
for any damages caused by any competing robots.
Each
contestant must sign a waiver of liability prior to the competition. If
the waiver is not signed, the robot will not be allowed to compete.
Appendix
1- Course Layout Guidelines
When designing an SRS Robo-Magellan course, either for practice or
competition, the following guidelines should be considered:
The
course boundaries should be a rectangle or at least a polygon. The
course should not have out of bounds sections located within the
perimeter of the main course boundaries.
The actual distance
from the start point to the destination cone, along the most reasonable
path of navigation, should not be more than 1,000'.
Three
bonus cones are suggested. One should be placed close to the most
reasonable path between the starting point and the destination cone and
have a multiplier of 0.8 or 0.9. A second cone should be placed in an
area that is reachable (doesn't have any terrain or obstacles more
difficult than the rest of the course) but is around 100 feet off the
most reasonable navigation path. That cone should have a multiplier of
0.5 to 0.7. Finally, one cone should be placed such that, without
unusual or exceptionally well-designed navigational capability, robots
will not be able to reach it. That cone should have a bonus multiplier
of 0.1 or 0.2. Mandatory bonus waypoints will normally have a
multiplier of 0.9.
Mandatory bonus waypoints should only be
used if the judge is relatively certain most robots in the competition
can navigate successfully to intermediate waypoints. Bonus waypoints
may allow longer distances in a more confined space or provide for a
more challenging route. A bonus waypoint may also be used to locate a
start and final destination relatively close to each other (or the use
of the same point for the start and destination) to provide a more
satisfactory spectator experience. Judges should keep in mind, if more
than one mandatory waypoint is designated, a specific order should not
be designated unless absolutely necessary because contestants choosing
multiple strategies to travel to mandatory waypoints will make a more
interesting contest.
The robot should have to travel over a
variety of diverse terrain such as grass, sand and concrete. There
should be some spots where GPS coverage is poor or doesn't exist.
Obstacles such as trees, garbage cans and park benches should be
included. Running along a hill or bank is challenging for some
navigation hardware and should be incorporated into the course if
possible.
The robots should not be able to see the
destination cone until it has traveled at least half way to the cone. A
wall, hill or other obstacle may hide the cone. There should be no
straight-line path between the start and destination points without
some significant obstacle such as a curb, building, tree, stream,
shrubbery or other similar barrier.
The course must not be
impossible. A more satisfying contest for both builders and spectators
will be had if robots are scored by time rather than distance to the
destination cone.
Google Earth (earth.google.com) is an
excellent resource for highly accurate position readings on
start/destination points and intermediate bonus waypoints. When
choosing points, consider features like sidewalk corners, buildings and
playground equipment to make cone placement more accurate. Recording
latitudes and longitudes that are accurate with respect to each other
is more important than recording latitudes and longitudes that are
accurate with respect to surveyed points. In other words, it's more
important a builder knows the distance and bearing between points than
it is for them to accurately navigate to a surveyed location.
Appendix
2 - Intended Rule Evolution
As
Magellan robots become more capable, it is the intention of the SRS to
evolve these rules to present a greater challenge. The following
proposals are not currently part of the Robo-Magellan rules but are
provided to give builders a better idea of how the contest may be run
in the future so they can design their robots more appropriately.
The
maximum distance between the starting point and the destination cone
will be increased. The difficulty of the terrain will become more
complex by adding steeper hills, more varied surfaces, etc. Other
changes may be made to increase the difficulty of the contest.
The
SRS intends to drop the rule stating contestants can walk the course
for the purpose of taking measurements. The reason for dropping the
rule is to offload more of the obstacle avoidance and path planning
intelligence from the contestant to the robot. Because of this intended
direction, we will continue supplying coordinates in written form at
the beginning of each contest. Some sort of electronic distribution of
the coordinates is being considered but the delivery mechanism has not
been finalized.
The SRS does not intend to increase the
maximum weight and size of a robot unless it becomes obvious that
robots can no longer be built to run SRS Robo-Magellan courses without
being physically larger or heavier. This is unlikely.
Physical
Platform:
The EVErobotics
Robo-Magellan entrant is built on a Traaxxas Stampede 1/10th scale
electric truck frame. We were able to reuse the stock speed controller
and steering servo by substituting the radio receiver module's control
signals with pulse-out signals output by a micro-controller. The
control signals consist of 50 Hertz positive TTL
pulses of between 1mS and 2mS with 1.5mS as null for both steering and
throttle.
Traxxas,
Stampede Frame
Stampede
Transmission
Encoder Assembly
We replaced the stock electric motor with a gear motor,
P/N: MP-28005-385
sold by BaneBots to achieve a
gear reduction of 5:1 for constant torque and low speed at
optimum motor rpm. The stock drive train configuration gives the truck
a 30 mph top speed! We want less than 10 mph. The pinion gear had to be
bored out from 3mm to 6mm to accommodate
the larger diameter gear motor shaft.
Encoder With Cover Removed
Encoder Components
Bane Bots MP-28005-385, 5:1 Planetary Gear-Motor
The stock springs on the truck frame were replaced with heavier
springs to enable the frame to support the
added weight of batteries, embedded computer, sensors, and
micro-controllers. Also, we will eventually have to retrofit
the drive-train with metal parts when it fails from moving 3-5 times
more mass than it was designed for.
Controllers:
The micro-controllers used in the robot are two Coridium
ARMmite Pro
single board programmable controllers. The ARMmite is
programmable in C or BASIC. One controller (the platform
controller) is used to manage the sonar sensors, IR rangefinders,
bumber switches, and control
throttle, brake, and steering.
We use the other one (the navigation controller) to process
data from the
electronic compass, optical encoder, GPS module, and accelerometer.
Lastly, we have
integrated an Acrosser
AR-B5230 embedded computer into the design.
The computer is directly connected to the web camera and also processes
data from all of the sensors
to form a map of the robot's environment. The computer also serves as
an
embedded development platform for its own software as well as
the attached peripheral controllers, and as a means
for remote control and/or remote monitoring of the robot via
bluetooth.
Coridium ARMmite Pro, Single Board Programmable Controller
The
compass and encoder are used together to generate vectors, and the
robot's position is estimated by combining vector addition,
accelerometer data, and GPS data. The sonar and infrared rangefinders
and bumper switches are used for near field navigation and object
avoidance. Lastly, the web camera is used to visually identify the
traffic cone and guide the robot in to touch it.