Are two speed transmissions worth it?

[MrForbes]

The discussion about automatic shifting is interesting.....do any of you know much about automotive automatic transmissions? In the old days before computers, there were two ways that they were designed. One used a vacuum modulator, which essentially measures the load on the engine. This would be analogous to the current detection algorithm. The other used a combination of throttle position and vehicle speed. This would be analgous to the encoder method.

[Joel J]

Originally Posted by squirrel

The discussion about automatic shifting is interesting.....do any of you know much about automotive automatic transmissions? In the old days before computers, there were two ways that they were designed. One used a vacuum modulator, which essentially measures the load on the engine. This would be analogous to the current detection algorithm. The other used a combination of throttle position and vehicle speed. This would be analgous to the encoder method.

Which one saw more success? LOL.

[techtiger1]

I agree the automatic shifting in terms of current is an interesting topic maybe someone from 33 can come and explain what they used for software and sensors on there four speed. Two speed transmissions have proven to be quite useful for 1251 as we have used them 2 years out of our 4 year existance. Both the games (06-07) had uses for a high and low gear. 06 becuase the field was open and you had to get to places fast and 07 primarly becuase you needed to get to the tubes fast but you needed a low gear to get into position to make the ringer count and hold your ground.

Drew

[Alex Cormier]

Originally Posted by techtiger1

I agree the automatic shifting in terms of current is an interesting topic maybe someone from 33 can come and explain what they used for software and sensors on there four speed. Two speed transmissions have proven to be quite useful for 1251 as we have used them 2 years out of our 4 year existance. Both the games (06-07) had uses for a high and low gear. 06 becuase the field was open and you had to get to places fast and 07 primarly becuase you needed to get to the tubes fast but you needed a low gear to get into position to make the ringer count and hold your ground.

Drew

Team 33 as well as 1126 has used encoders to determine when to shift and such. Here's a picture showing the eoncoder in red.

[Brandon Holley]

There is no correct answer here.

The game greatly determines if you'll need to shift or not. This year we chose to go with a 6WD single speed, and NO ONE on our team regrets that decision. Our drivetrain was very maneuverable and most of all...agile. We could get from A to B in an instant (or in the case of Finals match 3 of the Boston regional, middle of the field to top of 69 in 3 seconds).

We wanted our robot to score, and concentrate on scoring. If we were going to get in a pushing match, we were going to be wasting our time. We would just go out and if someone was getting in our way, use our agile-ness to "juke" our opponents out.

To shift or not to shift...that is the question.....and i think the best time to answer it is the first saturday in January.

[Athleticgirl389]

I say [for our team] most deffinately worth it. We've used 2 speeds as long as I can remember. This year, having two speeds really gives us the option of doing offense or deffense [and we found we are better at defense by a wide margin]. Having one speed is ok, but I prefer having the two; one for more traction and one for speed [IE getting across the field fast] As long as you are good with the shifting, 2 speeds come in VERY handy

[CrosbyAR]

Originally Posted by Tom Bottiglieri

You can only "push" with as much power as it takes to break your wheels loose, so I think proper weight distribution and wheel selection is more important than shifting.
...

While I wouldnt say more important, I would agree that it is equally important. I think each game effects the consideration for a shifting transmission. This year seemed to be a good year to shift, especially if your drivers use it. Even though we went with an AM shifter and it worked well, I do feel that if we had spent a little more time with weight distribution we wouldnt have gotten pushed around even as much as we did.

-Alex

[MrForbes]

Originally Posted by Joel J.

Which one saw more success? LOL.

Both saw equal success in the market, the vacuum system provided a better shift "feel", the mechanical system cost less to make.

....

as to the need for two speeds....if you choose to go with two speeds, you can have a more versatile robot. 1726 built a scoring robot, but with a strong 2 speed drivetrain, and more than once we changed strategy and played only defense in a match.

[Cartwright]

This year our 2 speed transmission was pretty good. In each speed there were some drawbacks, but overall we worked well, and with our chassis and nice AndyMark wheels we were pretty hard to move by defense and we sped along quickly. One thing that helps a lot is pneumatic brakes though.

[DBiehl]

I think that it sometimes depends on the game too. If there's a lot of empty field to drive across like last year but still with the need for high torque, a 2 speed transmission was great. This year, there wasn't as big of a need for both a high speed or a low speed, you could go either way and win pushing matches or try to just swerve around the defense altogether. We used 2 speed transmissions for at least the past 2 seasons, and there have been benefits to it both times, especially last year.

[Pavan Dave]

Originally Posted by Al Skierkiewicz

Teams should analyze the game each year before they make a decision on the transmission or other parts of the robot. There are years in which two speeds are optimum and other years single speed is best. The same can be said for treads, crab drive, multi-wheel or omni-wheels, large diameter or small diameter, aritculated arms, etc. In a defensive game, low speed pushers may be best. In a game where a robot must travel a distance often than high speed might be best. In a year where you might climb a ramp, a high speed only box may not work. There is no hard and fast rule on this decision. Analyze, brain storm and play the game with miniatures or team members playing the robot parts. Use your technology wisely.

I agree with you and at the same time disagree with you. The last two years, I have witnessed that have a two speed shifter would have been very optimal. This year as well as last, offense and defense were very important parts of the game, and I think that that will remain a consistency in the future games for years to come. Therefore I believe that although you cannot make many major decisions before the game is released, a two speed shifter would be a huge benefit to start researching into because sooner or later you might realize that with two weeks left in the season that you really do need one.

Pavan.

[Tom Bishop]

We used AM G2's and we were very pleased with the performance. We kept them in low most of the time for precise manuevering when scoring and anti-defense (resisting getting pushed while scoring). On the other hand, sometimes we had to get somewhere in a hurry (get a tube, get to a ramp), so we put it in high. Getting up ramps was much easier in low. It's nice to have options

If you don't like the weight you could always take the Poof's option! 1.1 lbs per side.

[swamp_child]

May have been said but you dont need 6 wheel drive.
this year we used 4 wheel drive, but we had six, and offsetted the center wheel down. We noticed that on the 05 and 06 bots the front hardly ever hit the ground

[Cartwright]

Originally Posted by Cartwright

This year our 2 speed transmission was pretty good. In each speed there were some drawbacks, but overall we worked well, and with our chassis and nice AndyMark wheels we were pretty hard to move by defense and we sped along quickly. One thing that helps a lot is pneumatic brakes though.

Sorry a correction must be made. These were IFI wheels not AndyMark. The gearboxes were AndyMark, which had good shifting. They worked great!