Are two speed transmissions worth it?

[=Martin=Taylor=]

I am the only one to have voted "no" so far...

We used our 2 speed AM shifters 1 out of every 2 matches this year. They helped us dart across the field, but we never used them for an extended period of time.

I'll admit they weren't useless... but they weren't worth the weight of the pneumatics.

If you're going to use pneumatics anyways I would say "go ahead." But otherwise save the weight and put it where it counts - in the scoring device.

[Alpha 997]

Originally Posted by Hachiban VIII

I am the only one to have voted "no" so far...

We used our 2 speed AM shifters 1 out of every 2 matches this year. They helped us dart across the field, but we never used them for an extended period of time.

I'll admit they weren't useless... but they weren't worth the weight of the pneumatics.

If you're going to use pneumatics anyways I would say "go ahead." But otherwise save the weight and put it where it counts - in the scoring device.

Yeah but there are shifting device that does not require pneumatics thought. Forgot what they are called but they run on electricity and weights like nothing.

[Alex Cormier]

Originally Posted by Alpha 997

Yeah but there are shifting device that does not require pneumatics thought. Forgot what they are called but they run on electricity and weights like nothing.

servos.

I love transmissions and like the 4 speed auto's better then anything else. They give you the speed and pushing power you need and a mix in the middle to not lose power.

[Alpha 997]

Originally Posted by Alex Cormier

servos.

Yeah, that's it.

[thefro526]

The pneumatics are not a problem we always use them.

[rachal]

We got two speed working pretty well in 2005 and 2006 with no technical problems, but the drivers got so caught up in the match that they would forget to switch gears and got pushed around. I guess it's fine when your drivers have had enough practice though

But yea, besides the question of whether your drivers will use it, a nice 5-15 two speed is really worth the extra work.

[Danny McC]

Yes. According to everything these people have said i would pretty much say they are worth. And apparently if i dont say that they are i cant work on the robot next year. And that makes me sad =(

[mikeleslie]

We used the 2 speed AM trans mostly to reduce the power consumption in a heavily defensive match. When in low (less then 5fps) we were able to push most teams (6 wheel, roughtop) and still have the available power to use the rest of hte bot. In previous years (1 spd) , a pushing match would use up everything we had. This year, the field could really be viewed as "short" so a 2 spd trans was not as useable as the prevoius year, where you had a clear 50ft run.

Also, before you look the "auto-shift" think about the situations. If you just got into a pushing match, using up 1 or 2 cycles (electric shift) to shift will kill you. High gear is great for getting you close to where you need to be quickly (.5s faster at 1/2 field for example) and low gear makes the bot have finer control (more motor turns per foot) and more power to push.

As far as electric shifting, the servo works but it's slower than pneumatics, there are not currently any solenoids allowed as they are just another form of and electric motor.

[65_Xero_Huskie]

We never use a 2 speed transmission. I personally dont think its worth it, because our robot has always been fast enough for us and strong enough to push many robots. People always ask if we have 2 speed transmissions and are surprised when we say no. Its up to you if you want to try it.

[robotguru1717]

Yes! being able to sit and push is very important and people have mention having a high speed gear to break away. Its also important for the defensive bot to have a high gear because i saw in several matches that a team that was ment as a pusher couldn't catch up to the other robot to do what it was designed to. The 2 speed transmition allows you all this flexibility. I think three speeds is a bit overkill however, but if you have the weight...why not.

[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.

[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.

[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.