Re: What would you buy if you could?
 

I would like to have a compact variable speed mechanical transmission something like this one, though it probably works in one direction only:

http://books.google.com/books?id=wSQ..._brr=1#PPA3,M1

http://www.google.com/patents?id=_Ml...ad=0_1#PPP4,M1

Maybe old Ludwig Dieterich was on to something. He did have a number of patents...

Re: What would you buy if you could?
 

Those printers use a type of glue-impregnated ABS, if I'm not mistaken. The parts they make are fine for some applications, but they're really meant for prototypes. I wouldn't trust anything critical to that machine.

Re: What would you buy if you could?
 

Found another one. (link) (disk brakes on the same page)

Nice compact little module.

Ahh yes... And I found this sprocket (1/2 down the page) don't know the exact dimensions but I bet you it will fit the window :)

Re: What would you buy if you could?
 

This one apparently uses heated ABS (see "How does the process work?": http://www.dimensionprinting.com/3d-...nting-faq.aspx

Re: What would you buy if you could?
 

Would you buy a 4 speed gearbox, spur gear style? Also its lighter than the supershifter. Thatz what i would want.

Re: What would you buy if you could?
 

Would you ever really need four speeds?

There comes a point where you cannot go any slower than a certain speed because you are traction-limited by the coefficient of friction of your wheels, and nor would you be able to go above a certain speed because the distance needed to accelerate to that speed would be impossible on a FRC field.

Re: What would you buy if you could?
 

Maybe, maybe not. But you could utilize 2 or 3 of the speeds at the least and its still lighter than the supershifter. Also think about offseason events and all the things you could do with different speeds (pull a track, have a robot race with all you robots, show off to the community).

Think about it for a sec:

08:

-Needed an extreme high gear for the straightaways
-A Middle gear for turning and good handling
-A low gear to play defense on hurdling robots and for those times of traffic jams.

07:

-Needed an extreme high gear to go from one side of the field to the other
-A middle gear for turning and a good handling of the bot
-A low gear for what a lot of teams did, play defense.

06:

-A high gear to go from side to side
-A second gear for turning and handling
-A third gear for staying on the ramp
-A low gear for climbing the ramp

In my opinion there is a need for it, thats why people use dewalts. But with dewalts there are so many mods and only a single cim so far. The shifting is terrible. Also what if your programmer can make a line of code that would allow easy on the fly shifting. Your in normal gear and when you press the right trigger, bam, high gear. Your in normal gear and when you press the left trigger, bam, a low gear with pushing power.

Re: What would you buy if you could?
 

I'm going to agree with arthur. 4 is a bit excessive. I would think 2 is the most you really need. 3 is nice (although it is easier to build a 4 speed gearbox than a 3 speed).

I want linear bearings for regular 1x1 tubing. That would be nice.

-Vivek

Re: What would you buy if you could?
 

That is why i said four speed, an extra gear would just available and 4 speed is extremely easy to build.

Re: What would you buy if you could?
 

Something similar to this:
http://www.chiefdelphi.com/media/photos/31607
would be extremely useful, if that is what you were going for.

Re: What would you buy if you could?
 

Just remember that shifting is never instantaneous.

Some of your circumstances where you list as needing three or more speeds can be accomplished with two (or even one) for less weight and less complexity. Or, things like greater control while turning can be accomplished through code algorithms that can "detect turning" and limit the maximum turn/spin rate of the robot instead of adding weight to add another speed to your transmission.

I'm not saying that designing and prototyping a four speed transmission is bad; on the contrary it would most likely be a great learning experience for the mechanically minded people. But the practical implications on the FRC competition field would make any benefits limited, as once you go above two or three speeds, it would probably be less complex to design and fabricate a CVT transmission than a fixed ratio one.

Robotics is not just about solving problems mechanically*; it's about finding the most efficient solution to the problem at hand.


* As much as I wish... Who needs a gyro when you can build a south pointing chariot? :rolleyes:

Re: What would you buy if you could?
 

The main reason for the 4 speed tranny is that i've seen some teams use the most out of one. I forgot the team number, but i will post it after i find it. But thanks arthur for your input.

Re: What would you buy if you could?
 

Yes, something like that, if commercially available, would be great. Especially for teams with limited machining capabilities.

-Vivek

Re: What would you buy if you could?
 

My question to CD and to the FIRST Community is if a 4 speed tranny was avaliable and it weighed about the Super Shifter (probably less). The price would be a tad bit more, would you buy it?

Re: What would you buy if you could?
 

Oh wow what a list... but here's a few of the tops:

>A Hurco VM2 for the team with a 4th axis or maybe even a VMX series with a two-axis trunnion table.

>A box full of Sick LIDAR units.

>Some high-frequency 16-bit chopper drives that use some kind of serial communications instead of PWM.

-q