An Exercise: Pros and Cons Of A Water Game

[falconmaster]

Originally Posted by PhilBot

For reference , I'm an underwater robotics professional (software), 20 years in the business, mainly tethered robots, commerical or military WORK vehicles (not research or university projects).

Observations:

Building a dumb, tethered, shallow-water robot that swims around and does some basic stuff can be fun and relativley straight forward. I've done it... http://www.gearsinc.org/image/tid/15

Building a smart, untethered, robot that swims around and does ANYTHING at ALL can be a HUGE challenge.

Here are some of the problems I see with a FRC style underwater game:

1) Multiple tethered robots can't really be let loose in the same pool without a lot of supervision, otherwise you end up with a mess of twisted cables. Radio doesn't work through water, so you have a FLL-Sytle one-at-a-time scenario with wires.

2) Navigation underwater is extremely difficult (unless you use wheels or tracks but what's the point of that) and you have the 6 degrees of freedom to deal with, so any sort of autonomous behavior is very difficult. It's easy to "propose" a method that will work, but try and find somone who's done it for less than $10,000

3) Water is a VERY unforgiving environment. Even if you assume that fresh water is relatively non conductive, you really have a lot of trouble keeping it out of any "downside" electronics, so the easiest strategy it to leave all the smarts on the dry end of the cable. The robot just becomes a dumb toy. Putting smarts in the robot is the ultimate goal, but generic hardware typically just insn't suited.

4) Vision systems are severly challenged underwater. The optics aren't the same as in the air, and distance is a problem. cameras don't give a good depth of field, or spacial reference, so it's very easy to lose orientation.

5) Seeing into a pool from outside is problematic. It's not to bad if you have side windows, but doing anything from above is tough.

So, technologically speaking it's a hard nut to crack, unless you have some professional tethers, waterproof housings and a good camera system. Plus, expect to lose more electronics from water intrusion than you would normally lose from normal techical problems. Water is a B*tch.

Having said all that, I think coming up with a game to give kids exposure to the underwater side of robotics is a GREAT idea. The trick would be to take the "concepts" of FIRST and adapt it to a totally new underwater game environment.

The flaw would be to look at the sophistication that we now have in FRC, VEX and FLL and assume that we can jump right into the underwater world.
Not True.

There needs to be a whole new set of tools and components developed to let us ease into it slowly. Some of the IFI hardware applies, but it needs to be reconfigured... eg: the Flat IFI RC unit would need to be re-shaped to fit inside a long 2" tube. Likewise the speed controllers need to be remodeled so that the hot part can be exposed to a surface cooled by the pool water (no real chance of that fan cooling working for long)

As an underwater professional I see the industry still in it's infancy, despite what is already being acheived. I think there is the potential for huge growth, and as such, LOTS of fun careers for future Engineers/Scientists.

My reason for starting to play with PVC bots is that I want to start moving down this road myself. Getting more kids involved with underwater technology... Start with the basics and look at where the most bang for the design buck can lead. I hope to get a test tank built at my facility and do a summer "underwater camp" next year for middle school kids.

To summarize:

Con: Many technical and procedural challenges

Pro: Hugely worthwile endeavor. Please let me help.

Phil.

I agree with many of your points

1. Yes tether management is a problem, but that is part of the drama and challenge. This can be minimized by putting all components on board the ROV. This would reduce the tether size and increase manageability. You would oly need control signals or basically tether that would be used by teams in the pit at an FRC event. It would be a lot longer. We have used 100 foot plus with no problems. We have done this.
2004
http://www.phxhs.k12.az.us/education...e41b725c1abb3b
2005
http://www.phxhs.k12.az.us/education..._id=1198816467
2006
http://www.phxhs.k12.az.us/education..._id=1198816528
2007
http://www.phxhs.k12.az.us/education...13&pagecat=323
We have even done multiple robots with multiple tethers with great success.

2. I agree navigation is difficult, again that is part of the challenge. you can mount a camera on a dive compass, it works and it gives the pilot or team captain a task he must attend to. You can use Inertial navigation units but they don't account for drift. You can get them fairly inexpensive.

3. Water is unforgiving, again that is part of the challenge. We have made simple housings to enclose all the robotic components and we have had a great deal of success.
http://www.phxhs.k12.az.us/education...13&pagecat=330

4. Yes this too is true, but using different angle lenses and focal lengths, this is not much of a problem. There are very many inexpensive cameras that can be used and making them water tight is very inexpensive.
http://www.phxhs.k12.az.us/education...60&pagecat=110

5. Seeing into a pool is not needed if you have many cameras in the pool that would project the images on a large video screen. You need a person to switch which cameras to use when to provide the audience with the desired view. You can even have the ROV's point of view. We have done this too.
We even did this in the dark.Doing it in the light would be so much easier.
http://www.h2orobots.org/summerindex.htm
select Team 1 Falcon Robotics, they had the best lighting so the video was better. In light this would have been no problem at all.

All in all
Pros-More challenging in many areas, not so challenging in others. Would also expose students to new problems faced in the real world. There would be more deliberateness in the competition rather than haphazardly moving around the field. It is a different paced excitement, but it is excitement none the less. Its another way to see if the FIRST model works in another venue than just a FIRST one. Besides most of the planet is water, we will have to confront this sometime.

Cons-it is different and challenging, not necessary more than FRC, just different. Different can seem hard to teams that have never done it. As a team that has, I can say its just different. It does fly in face of common sense putting electricity into water.

We hold an "underwater FIRST" in Arizona in June.
http://www.h2orobots.org/
Come take the challenge and find out for your self. Teams have most of the components already to get most of the rov built, that is how we got started.

Team 1726 The NERDS won the event last year!