[FTC]: FVC (Vex) VS. FTC (Tetrix)

[NalaTI]

Originally Posted by Rick TYler

Their 2008-9 robot makes good use of VEX materials: http://www.technoguards.org/sites/de...s/DSCN1638.jpg.

Yep, it was a good, inexpensive bumper material. However, that was also the only material piece that we had to go back and smooth out the edges for safety. If there was some form of plate we would never have used it.

This year, VEX parts are not allowed - so we'll do something else!

[NalaTI]

Originally Posted by bellpride

When a robot (any "middleweight" robot) is bending VEX metal, it's time to reconsider the design...

Yep, definitely true!

Originally Posted by bellpride

I've always been curious, because last year I had the impression that Tetrix motors were better than VEX ones. Looking at FTC matches at Atlanta, the robots weren't moving that much faster than VRC ones in Dallas. Is that because they were geared way down?

The speed of a motor is not the same thing as the power of a motor. I saw some VERY fast (Tetrix) robots where they were geared up, and still had plenty of power. The problem with speed is controllability - If you go too fast, you can't do what you want either!

---

I don't disagree with any of the points that are made by people that prefer VEX. I've not used it in any great detail, so can't speak in valid comparison. What gets me annoyed is when I see someone bashing the Tetrix stuff without their ever using it as well.

As a Tetrix user, I realize there are lots of shortcomings to this system. But now it's what we've learned and know. Are we going to go spend the money for a new VEX kit, and then work to join an organization that isn't related to where we've been? Doesn't seem likely even if VEX was "better".

It seems to me that the best judge would be some new engineering students that have not used either... We don't have any of those here - so that's what makes this whole Religious/Political argument kinda pointless.

[ttldomination]

hahaha. this debate sounds a lot like another one of those with no answers.

I've worked with both platforms and I must say, that I was extremely dissappointed with Tetrix, simply of the compatability of LEGO parts was poor, and then the hardware option is pitiful compared to VEX, but if we look at the competitions...

I prefer FTC over VRC, especially this year with the two games. To me, hot shot just seems more exciting than clean sweep, and I don't think I need to explain this. Not to mention that this year, FIRST's extra materials list is extremely beast, and the designs are even more flexible than last year.

What I'm interested to see is the VEX high powered motor. Right now, the Tetrix kit offers super-motors compared to the VEX/Lego motors. But these more powerful motors allow for more powerful/robust designs. When VEX releases the powerful motors, I think that favor will go back towards VRC, because then, you can do almost EVERYTHING with more powerful motors, which you really can't do in FTC.

[JesseK]

So generally speaking, teams who have 4 VEX motors on their drive train and a 25-lb VEX robot will typically not move as fast as an FTC robot that weighs 25lbs with 2 motors on the drive train (#'s below). Yes, there are tradeoffs. It will be interesting to see where teams decide to fit all of the electronics for 8 Tetrix motors, 3 lego motors, 4 Servos, and a bajillion sensors...

FTC's structural components leave ALOT ... wait ... ALOT to be desired. They're difficult to work with to do tricky things, and I think part of the challenge for this year will be getting those structural components to become something that can move the balls into the goals. Alas, to FTC's aid, the GDC has allowed many extra materials.

----

FTC motors output just over 1.5 N*m of torque at 150 RPM whereas the VEX motors output 0.73 N*m at 100 RPM. (is that math right? I don't remember a 0.73 when I did it a long time ago...). For comparison, an FRC FP motor driven thru an AM Planetary has the same torque as the FTC motor but at a much higher RPM (4800-ish).

The tradeoffs: FTC motors require more complicated electronics, whereas the VEX motors already have a built-in controller. FTC motors require more power, which reduces performance at the end of the match if the robot constantly draws excessive power due to poor gearing choice.

[BLAQmx]

Originally Posted by Chris is me

I don't like to use computers...

(out of context) this made me chuckle. It sounds like you are being dragged into the future kicking and screaming

[Rick TYler]

Originally Posted by JesseK

So generally speaking, teams who have 4 VEX motors on their drive train and a 25-lb VEX robot will typically not move as fast as an FTC robot that weighs 25lbs with 2 motors on the drive train.

Your conclusion as stated is unassailable.

Three of the robots we sent to VEX Worlds weighed a COMBINED total of 25 pounds. Tetrix robots tend to be very heavy. I expect that it is because the wheels, motors, gears, and batteries are heavy, and, despite using aluminum, the basic Tetrix aluminum is thick, large in cross section and weighty. We actually ripped some of the c-channel into thinner pieces to reduce bulk. It's strong, but since it only comes in one real cross-sectional size, you have to use the giant c-channel even where you don't really need it. Not all tools are hammers, and not all problems are nails.

As long as FIRST recommends not gearing up the Tetrix motors (see last year's Q&A) FTC robots won't have a big speed advantage. We tried gearing up the motors last year and broke gearheads. Shortly thereafter FIRST told teams to use direct-drive or gear down, so I'm guessing we weren't the only ones with the problem. A direct-drive FTC robot with 4" wheels has about a 2.6 fps potential. Certainly no faster than the average VRC robot, but it will have substantially more "pushing power" with the bigger motors (as long as they don't stall and burn out).

Some of the big steel VEX robots can be pretty darned heavy, too. Most of these are geared for about 2 fps. Five of our six VRC robots last year were geared variously at 3.6 to 4 fps. This video is a pretty good example of what lightweight robot design can do: http://www.youtube.com/watch?v=aIsQckNv9zM. I don't think you could build that 8-pound robot with Tetrix parts.

Someone elsewhere in this thread mentioned that they didn't like people bashing Tetrix who hadn't tried it. That is a fair point. We had three FTC and six VRC teams last year, so I suspect that there aren't a lot of programs around that have wider experience in the two platforms than we do. Given our program's goal of delivering a high-quality competition robotics program to the greatest number of students for the least money, we have chosen to focus on VRC and not FTC. Especially when you start adding up the annual fee (275+149) times our 7-10 teams, the bang for our FTC buck starts to fizzle. For eight returning teams, which takes the kit cost out of the equation, FTC would cost us $3,392. VRC registration for eight teams is $250. We could fund an additional 2.3 (or so) VRC teams for that $3k, and reach 15 more students.

I do like the sensor suite in FTC, and the FIRST volunteers here in Washington are an outstanding bunch of folks. We will still have at least one FTC team as long as we have students that prefer it. I think we should all continue to share our experiences on Delphi, and remember that engineering and science isn't about cheerleading, it's about evaluating problems and designing or choosing the best solution. As lead mentor for our program, my problem was "STEM+fun bang for the buck" not "how many weights can I hang on a beam" and so we decided to focus future team growth on VRC. YMMV.

[JVN]

Originally Posted by NalaTI

http://1.bp.blogspot.com/_sTlYdhwqT5...el-weights.jpg

*Shrug*

http://www.vexforum.com/gallery/show...original=1&c=9

VEX 1x2x35 C-Channel, $17.99 for (4X)
TETRIX (TM) Channel, $15.96 for (1X)

[Rich Kressly]

"You must spread some Reputation around before giving it to JVN again."

[ttldomination]

Hahahaha. FTC, ball's in your court.

[Akash Rastogi]

Originally Posted by JVN

*Shrug*

http://www.vexforum.com/gallery/show...original=1&c=9

VEX 1x2x35 C-Channel, $17.99 for (4X)
TETRIX (TM) Channel, $15.96 for (1X)

rofl

[NalaTI]

Originally Posted by JVN

*Shrug*

http://www.vexforum.com/gallery/show...original=1&c=9

VEX 1x2x35 C-Channel, $17.99 for (4X)
TETRIX (TM) Channel, $15.96 for (1X)

http://tinyurl.com/krt2o9

No question - Vex wins on cost. Price was never the issue.

[JesseK]

Originally Posted by NalaTI

No question - Vex wins on cost. Price was never the issue.

Indeed, many people who do FTC don't do it because of it's superior cost analysis. Yet many people who approach this argument seem to only approach it from a cost perspective, or cost is always somewhere in the argument regardless of what the specific topic is. I like the original intent of this thread, and hopefully it will get back on track?

This list intentionally has cost left out of it, and is a composite of the posts thus far. I tried to only put things in the list that add to or subtract from a student's experience in either program. It also ignores the fact that teams may already have had substantial resources invested in one program or the other, since in the longer term everyone gets to that point regardless of the program. Swapping to the other is just a matter of making the decision and doing it, imo (of course...).

The "+N" means "N" people stated their opinions in this case, thus far. Don't agree? Post the opinion. Differing opinions should be stated as, for example "(+2)(-3)". Weighing facts with +/-N only serves as attempts to bias someone who's making a weighted decision.

FTC
Pros

• Extra material is allowed, including sheet plastics, aluminum, & cord (allows more creativity, +2)
• Better regional competition experience (+3)
• Stronger motors & gears
• Uses the NXT brick, which many of your mentored Jr. FLL & FLL teams are already familiar with for programming. LabView also transitions to FRC.
• More connections to college scholarships
• More & better (+2) sensors

Cons

• Connectivity issues at competition (resolved though, right? Didn't see any issues in Atlanta)
• LEGO parts aren't very compatible with the TETRIX parts (But if they ever are, look out! I know some 8 year olds with mad LEGO skillz!)
  
• Need multiple laptops/blue tooth to demo multiple bots
• Uses bluetooth (-1)

VRC
Pros

• Amazing World Championships, better than Atlanta (+3)
• More variety in the parts, including complex/intricate parts for more in-depth designs.
• Generally speaking, more matches per event
• Higher quantity of competitions per region
• College level division
• Steel parts for structure makes a stronger structure where needed
• Established community where many collaborate on pushing the limits of the VEX system even outside of VRC.
• Entire winning alliance qualifies for nationals
• Online challenges for those unable to attend competitions (link?)
• Skills challenges that are not based upon cooperation in competition

Cons

• Relatively weak motors

Topics that haven't been discussed:

• Number of mentors per student for each program

As Rich Kressly stated in his very well-worded post: you can't look at this from a sheer quantity of pros/cons perspective. Each must be weighed against your local situation and then the best decision can be made.

[Rick TYler]

Originally Posted by JesseK

FTC
Pros
[*]Better regional competition experience (+3)

You are really going to have to explain this one.

Even the most ardent FIRST loyalist wouldn't describe the experience of the last year's FTC/LEGO competition season as anything other than a complete train wreck. I don't believe any VRC event was canceled because the field didn't work, or lasted until late until the night for the same reason, or only had two or three qualifying matches.

I would have added:

VRC Pros

* Better regional competition experience +10
* The whole winning alliance qualifies for a Championship event +3
* More regional competitions, more chances to play
* The Skills Challenges for programming and driver skills give more competition opportunities than simply winning the tournament +3
* The online design challenges are far more extensive than FTC's animation challenge, and provide another route to world competition
* Teams that are remote or can't afford to travel may still participate in the online challenges
* Finalist Alliances in North America qualify to participate in the Championship of the Americas -- another super-regional in addition to Worlds
* Doesn't use Bluetooth

* Allows schools, clubs and sponsors to expose a lot more students to STEM for the same money +100

[JesseK]

Originally Posted by Rick TYler

You are really going to have to explain this one.

+3 meant that 3 people in this thread said that. They're opinions, and not necessarily mine. Sorry I didn't put a little teeny disclaimer somewhere obvious, I thought people would actually read what I wrote.

[EricH]

Isn't FTC not available in certain areas, or am I still in 2008 on that? If it isn't available, that's a con, as VRC has more areas with competitions.