V5 vs Cortex during competitions & V5 selling question

VEX V5 General Discussion General Forum
#1

For people who have had a chance to compete in tournaments that include both V5 and Cortex robots, do you have any new insights or comments regarding their end-of-season competitiveness for the 2018-2019 season? For anyone else, is there an overwhelming competition-related reason why you would go with one over the other?

In super-specifics, what results have you seen in the drivetrains? What combinations of motors, motor gears, and gear ratios have you seen do well (or poorly) against each other? This is the only area where we think the V5 might pull ahead of the Cortex in our design, but currently we don’t see it being a big enough difference to be a deciding factor. We have a 6 motor HS drivetrain that gets around the field well, gets on the platform fine, and doesn’t stall out when pushing random heavy objects. We would only be able to have a 4 motor V5 drivetrain.

Our focus is solely on this season (so we are not concerned with the phase-out of the Cortex or anything related to future-season benefits) and in particular we are interested in the competitiveness expected for Signature Events and Worlds. We currently feel that at local competitions and Regionals we will be high-level competitive with Cortex, but we want to know what people are seeing in other areas.

We have only gotten to go to 1 competition due to various V5 issues we had to work through, and our take from that competition was that we would have been far better off having perfected a Cortex robot instead of wasting months on V5. After the competition, the team came together and re-did the robot using the Cortex system (and of course incorporating multiple other changes that they decided were necessary as well) and are extremely please with the result. So now we have a big, expensive pile of barely-used V5 equipment that we are considering selling and we’re trying to decide what to do. Budgeting and time constraints for a very small, independent team make it preferable to sell the V5 now (rather than building 2 robots for the current season or saving until next season) unless there is some solid evidence that we would need V5 to be competitive at Worlds for this season.

Regarding selling the V5 system - is it best just to do that on Ebay or is there a robot marketplace of some sort?

#2

DON’T GET RID OF YOUR V5 unless you need funds for something. V5 is all-around better or at least will be once the VCS kinks get worked out. A 4-motor high-speed V5 drive will be WAY faster and stronger than a 6 motor HS 393 drive. I’m sure that VEX will make the future games better for using 8 motors with (not 3 different tasks like Turning Point). If I were your team, I would (if you have enough parts), put the Cortex Bot off to the side (or have your drivers practice with it), and have your Builders build with the V5. Whenever there is a somewhat decent team with V5 (not a V5 clawbot, yes I’ve seen those), they almost always make it to finals. I have never seen a cortex alliance beat a V5 alliance. I can virtually guarantee you that the 2019 Worlds-winners will have V5.

#3

V5 is definitely way better than cortex, but a lot of people want v5 so you could sell it for a lot more than what you bought it for. I def wouldn’t sell it though because V5 doesn’t disconect nearly as much as cortex, and you get way more power with v5, and programming is easier, and wiring is easier, and the battery lasts alot longer, and everything is way more consistent because the motor power stays at 100% regardless of battery.

#4

I don’t think better is a factor at all… Unless you are planning to leave VEX shortly, you will be required to use V5 in the near future. If you want to continue competing, you must get it, better or worse. Whether you get it sooner or later should take into account more than “more power, more good”. To me, having the additional time to get used to the new system during the transition period is a major benefit of transitioning early. You won’t be behind on adapting while others are ahead.

There is also the issue of lead times. You do not want to get to the end of worlds one year, hear the announcement that next year’s game will no longer allow the Cortex system, and then find out that V5 still ships in eight months. In addition, as the transition occurs, Cortex equipment is being eliminated from production. You will reach a point where you can not buy new equipment without changing over. You will probably be able to find second hand parts from other teams, but eventually that too will dry up.

And of course, everything is subject to your team’s funding situation. Some sponsors may be more willing to help if you are a proactive early adopter, some may be more willing to help if you are at a deadline and no money means the end of your competing. Just depends. If you have the money to switch to V5, i think you should do it sooner rather than later.

#5

I think a good game design will stretch teams harder, not narrow the focus so they can put one motor per mechanism. You don’t see incredible engineering until you have very tight constraints. I want to see a game design that people say is impossible to do everything with only eight motors, and i want to see the teams that do it anyway.

They should also introduce a compact, low power motor/servo and allow several of them and limit you to 4 or so of the new motors. Give some incentive to be creative and create mechanisms that multitask.

#6

don’t sell your v5, eventually you’ll just have to buy more.

#7

At my first competition a four motor v5 drive train won a pushing match against a ten motor 393 drive train, both weighed 15 pounds with direct drive high speed motors .
It is possible for a good legacy robot to beat a v5 but you have to make use of the extra motors,and do not get into a pushing match.

#8

Thanks for the input!

It seems like we must just have worse luck with V5 compared to many of you. We’ve used it less than 2 months and already needed the brain replaced, a battery replaced, the radio replaced (lots of disconnect issues), and 3 motors replaced (1 jammed, 2 overheated). We also had problems using VCS for programming (lots of weird behaviors that seemed more like glitches than programming errors…); enough so that we weren’t able to get a fairly simple auton running correctly in a reasonable time so we had to settle for “shoot a ball”.

@Sylvie - our 6m HS Cortex seems fast and strong, and we have heard anecdotal evidence of robots with 6-8 393 motors out-pushing 2-4 V5 motor drivetrains. Is this not what you’ve seen in practice? We might try to pull together some parts for a V5 test bot & do some pushing matches.

@Waffles - we’ve found that the disconnects were far worse on V5 (during the competition we had disconnect/reconnects in 7 of 9 matches, usually 1-5 of them and lasting 3-10 seconds each). We also have found programming to be harder with VCS. The wiring is easier, but everything I’ve read on the forums indicates that it is just a matter of time before the wiring makes the ports stop working. We do like the battery power & consistency!

@Robo_Eng_13 - definitely worth considering more about future issues. Our main concern is with the current season, though, as we don’t know who will be continuing on to the next season and we have low funding. Trying to balance resources & options!

Thanks for the details! That’s pretty impressive. We really think the drivetrain is the one area where powerful motors are needed and the V5 might pull ahead, which is why we haven’t made a final decision yet. We had heard that a 6-8m 393 can outpush a 4m V5, but it sounds like what you’ve seen is totally different!

#9

VCS is not worth anyone’s time as it stands currently.

Robot Mesh Studio is a good alternative for most VCS users, with a competition-ready graphical option, C++ with a near-identical API to VCS C++, and the unique option to program robots in Python.

PROS has excellent C and C++ options for experienced users. If you’re using VEX C++ Pro in VCS as a “pro” option, you should actually be using PROS.

MATLAB/Simulink also works for V5 if you’d like to learn to use an industry-standard mathematics tool.

#10

@chrishamling take some notes :slight_smile:

@TeamTX - It sounds like you’ve had a lot of blown out v5 components which I would just attribute to bad luck. But I think this is a lot closer to the experience of most teams regarding cortexes and 393s.

-The v5 motors have over twice the power output of 393s. You can test this by putting the same shaft in a 100 RPM 393 motor and a 200 RPM v5 motor and spinning them opposite directions. The v5 motor will easily overpower the 393.

-The v5 motors have the option for 600 rpm cartridges. This allows your intake and flywheel to have much less friction because you need less gearing to achieve the same high RPM. (Maybe you have a catapult, but still : )

-The v5 motors also have an insane locking feature where they can hold their current position with many times their rotary power output. With 2 200 RPM motors locked on a 4" wheel, I physically could not rotate the 4" wheel when I gripped it and tried to spin it as hard as I could. (Granted I’m not exactly a body builder, but still.) If you need to hold your position when parking or to evade defense and don’t want to build a brake, this locking feature is your friend.

-The v5 brain at least in my experience is a lot more consistent than the cortex. I constantly had issues with blown cortex firmware etc, and the v5 brains simply don’t have those issues to nearly the same extent.

-The wires are much thicker, meaning there are no problems with wires breaking or getting damaged. And they clip into place very easily, so wiring in general becomes much easier and faster to do and undo.

-The built-in PID makes for much easier autonomous programming. I know you’ve had issues with autonomous but once you sort them out, the go-to-a-particular-position functions are a lifesaver.

Motors and brains shouldn’t be blowing out, but the warranty on those parts should mean you can return them and get new ones from vex. And I totally sympathize with your VCS struggles, which is why I switched to PROS. In PROS, you can set the motor voltage directly, there aren’t bizarre glitches, and the UI is a million times better. I can’t vouch for Robot Mesh Studio, but I’ve heard it’s equally well-designed and more beginner friendly. They’re probably both a lot better than VCS.

Think about it this way. Suppose your 393 design is 6 motors on the base, 2 on the flywheel, 1 on the feeder, 2 on the lift, and 1 on the wrist. If you switch to v5, you might put 4 on the base, 1 on the flywheel, 1 on the feeder, 1 on the lift, and 1 on the wrist. You now have less friction on the base, flywheel, and lift because you only need to attach 1 motor, and you have more power on every single subsystem. If these two robots faced each other, the v5 robot would have a huge advantage because it would simply be able to score faster and play defense more effectively.

All this is to say, v5 is still a brand new system and vex has done a completely abysmal questionable job in a lot of ways, but they’ve also totally nailed it in much bigger ways. All in all, it’s hard to imagine v5 not winning worlds.

#11

I’d genuinely be surprised if there is a single cortex robot in the final matches of worlds.

#12

I think @Xenon is absolutely right and being conservative with the cortex robot in the finals of worlds. I would be completely shocked if there is a single cortex robot in the finals of any division at worlds.
@TeamTX Your experience sounds very odd. I graduated high school last year but just recently went back and saw the new robot and stuff and I would say that I am absolutely stunned with how powerful V5 is. I would say spend more time with V5 because once it works it is insane. Our 1 turbo V5 motor is able to continually run, shoot, and recover faster than we can even time at its full 600RPM(averaging) for over 30 minutes. I don’t think any less than 4 393 motors would be able to power a 3000RPM flywheel running as hard as we did for that long.

#13