Aug 22, 2006

Competition Discussion & Questions

I was playing around with one of my bots today that uses the Play/Record block an unusual thought popped in my head. Let me see if I can explain it...

Let's say you have a competition where your bot must navigate a fixed-dimension field (let's say 10x10 feet). Let's also add in the fact that there are obstacles and objects to interact with on the field. (Can you tell I'm trying to avoid using a 3-letter acronym here?)

Finally, let's add in the fact that the bot will always start from the same exact position.

Okay, here's the question:

(Assuming memory isn't an issue, because it may very well be in the REAL WORLD)

What's to keep me from setting up a test field, putting in a Play/Record block configured for 5 minutes (300 seconds) and then recording my manually moving the bot around the field, interacting with objects, performing tasks, and then returning home?

If everything is in a fixed location, all I've got to do is drive the bot with my hand into the proper position for a task, use Motor A if required and move it to perform a task, and then move it on to the next task.

I realize that there might be subtle differences in measurements, but if we're dealing with a table of less than 10 feet, the bot probably won't encounter any major problems with playing back the recorded file. If I needed the bot to interact with objects with a degree of accuracy in the millimeters, I could see a problem, but I haven't seen too many competitions with that level of fine-tuned design.

Okay, thoughts? Is this allowed? Impossible with the current memory limits? What if memory isn't an issue by the time competition rolls around?

15 comments:

Christopher R. Smith (Littlehorn) said...

This is a good thought. This occurred to me while at NIWeek...I'll explain a bit.

Operational wise...It depends on the obstacles. See the NIWeek Challenge table pictures posted in the blog by Brian Davis. You might be able to makeout the 1x plates in the course (behind the date in Brian's photos). They altered the steering of the bot differently each time. The bot never went through this portion of the course the same way twice. I wanted to try the Record & Play during the challenge we decided it would not workout as planned. The bot would jump around and throw any programming off just enough to make life fun.

Now, I could see Record & Play working where the course surfaces would not make this sort of difference (ie. smooth sailing).

FLL Allowed? Prolly not. But, I could see it OK'd in some cases.

Chrisotpher

Jim Kelly said...

I haven't seen that the Record/Play block is illegal in FLL...

I saw the competition field last week with all the various 3-dimensional challenges the bots should tackle... let me tell you, if memory isn't an issue, I believe I could program a bot to handle most, if not all, of the tasks. The playing field is level and smooth, and the mat used has consistent dimensions and the element locations are very well designated.

I'm not bringing this up to cause problems for the FLL, but if it's not illegal, it's definitely a HUGE advantage over RCX bots.

Think about this - if it is legal but memory is an issue, you could still record maybe one or 2 of the more complicated tasks and save them as files on the brick. When the bot gets to the special spot, it plays the file and the complicated task is no sweat.

Jim

Jim Kelly said...

All this may be moot if someone can verify Record/Play block are not allowed in FLL.

J

Anonymous said...

I've tried it on the 2006 FLL table without success. Perhaps I am missing something, but I found that making a good recording of anything other than a very simple path is extremely difficult.

Jim Kelly said...

I have found by trial and error that the biggest problem with Record/Play is making certain your bot travels in a straight line. Even with paired NXT servos, some bots will be slightly off course if you watch them roll more than 10 feet or so...

But I was able to do over 60 seconds of recorded rolling movement once I got my wheels correctly synched up... this included 5 90 degree turns (left/right).

It convinced me that it could be done if you don't run out of memory.

Jim

Brian Davis said...

First, (or is that FIRST?) I expect Record & Play blocks to be legal, as limiting the existing language to make for an even playing field is... well, it would seem against the spirit to me. Also, using the Record & Play block with reasonable accuracy I find to be rather challenging. Moreover, if you want to make sure that this option is not allowed, as Chris mentioned you just need something that will make dead-reckoning inaccurate, even a little.

--
Brian Davis

David Levy said...

As this is my first year as an FLL coach, I don't know what the metrics are for judging. I would imagine that course completion is only one factor. If I were a judge I would take into account the amount and nature of the hard coded inputs used to accomplish this mission. For example - lets say the challenge was to travel from point A to point B. A weighting factor would be applied to each of the following solutions.

1) record and play ( lowest weight)
2) clocking a trial run of the robot as it travels from A to B. Code: "drive for n seconds"
3) Counting the rotations ( with a separate rot-sensor) on a similar trial run. Code: drive for n rotations
4) measuring the distance from A to B with a tape measure. Code: inputs abDistance , wheelDiameter. Calculate circumference of wheel from wheelDiameter. Derive required rotations from abDistance / circumference. ( highest weight)

Anonymous said...

David, the judging guidelines for the FLL competition are outlined in your Coach's Handbook. The kids' work with the robot is judged in two ways - 1, the actual robot performance on the obstacle course and 2, how well the kids can explain during an interview, how they approached the challenge (in other words, did the kids do the work or did the coach do it?)

As far as allowing Record/Play or not, the organizers are continually refining the rules of play, right up until tournament time. So just because they haven't disallowed this feature already, doesn't mean they won't change their minds to disallow it before competition. I wouldn't recommend that a team should rely on this method.

David Levy said...

"..2,how well the kids can explain during an interview, how they approached the challenge (in other words, did the kids do the work or did the coach do it?)"

So are you saying that technique wouldn't matter provided the kids convince the judges that the approach was legal and not the coaches doing?

Jim Kelly said...

The FLL rules makers will obviously have some work ahead of them with the NXT added to the mix...

Jim

GeekyTom said...

I'm a first year coach as well, I haven't seen anything about the record/play being illegal. but then again, my coach's handbook states that the ultrasonic sensor is not allowed, but on the website the allowable materials rules state that is is allowed. What gives?

David Levy said...

I think that the website would have the latest rules.

Do you think there would be an advantage over a third touch/light sensor on the RCX?

Maybe the FLL just wants to introduce the U-sensor.

Jim Kelly said...

Well, a lot of kids are already starting to experiment with the new FLL challenge... so if anyone knows someone up in the FLL chain of command, you might want to let them know about some of these concerns:

1. Ultrasonic allowed in one place, disallowed in another

2. Record/Play block - can it be used?

Any more questions?

Jim

lindazoe said...

When the Challenge is officially announced on Sept. 15, the web site will have a "rules" section with lots of details. There will also be a "missions" sections with the rules for each individual mission. (Check out the 2005 challenge to see examples.) There will also be a "Q&A" section for teams to ask specific questions or to get clarification. I can guarantee that some team will come up with a scenario that no one at FLL acticipated and FLL will have to decide what's allowed. Teams can email flltech@usfirst.org with questions, and Scott Evans will respond to them. Questions that may be of interest to all teams, or affect the missions of all teams, will be posted in the "Q&A" so it's very important for teams to check that link daily.

I've already asked about the page of decals that came with the NXT. The FLL rules say "no stickers" but Scott said the decals are official Lego parts, and may be used. I put the text decals just above the sensor ports to make it easier to remember which is the default port for each. So Scott may answer you now, or he may wait to post questions that would affect everyone until the "Q&A" is available to everyone.

Jim Kelly said...

Linda,

Thank you VERY MUCH for this info...

Jim

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