Drive systems ideas

[rcmolloy]

Well you have many numerous white paper at your disposal but I will give you a crash course in simple drive systems.

Direct vs. Chain/Belt

- Direct requires more room to incorporate 4 single geared gearboxes
- Direct only has a single speed controlled gear box (Unless you want to mount 4 shifting transmissions )
- Chain/Belt reduces space but tensioners and design quality will affect breakdowns
- Chains/Belts do allow you to have multiple non-driven wheels which worked great for this year
- If you were to go with Belts/Chain, Cyber Blue (234) has a white paper that revealed after testing that belts are more tedious to work with but they work better with a drive train

In my honest opinion, go with what the game play will be like. If there will be pushing and shoving, a Chain/Belt drive with 6 or 8 wheels will be optimal. If the game requires fast paced movement and little torque, then a direct driven omni-directional or mecanum wheel system is what you are going for.

Check out this top to see the multiple systems that are available.

http://www.chiefdelphi.com/forums/showthread.php?threadid=87786

Like I said, wait until you know your strategy before deciding on one.

Anyone else want to add? I know there is so much more that can be incorporated.

[JesseK]

Originally Posted by team3329

Our team used the standard 2010 KoP drive system this year since we were rookies and it worked fairly well, but we want to try something new this year. Does anyone know the advantages and disadvantages of chain vs direst drive vs gears vs belt drives? Trying to get a big picture to try various things (Provided they don't coast too much).

Keep in mind that there are KOP-based drive trains in the championship division finals every year ( I would say Einstein, but I'm not quite sure about 2006 or 2009). For these teams, the modifications to the KOP drive train are typically gearing-based (adjustments for speed, or addition of a shifting transmission), yet the basic design stays the same. The advantage these teams is only apparent when their manipulators appear to be better designed.

Simple drive train + Elegant manipulator
vs.
Elegant drive train + simple manipulator

So my recommendation is for your team to stick with what they know, and 'experiment' with various ways to drive manipulators (belts, direct drive, etc). That will teach you everything you will want to know while also maintaining a solid, reliable drive base.

[Jared Russell]

Originally Posted by JesseK

Simple drive train + Elegant manipulator
vs.
Elegant drive train + simple manipulator

[nitpick]Why can't everything be simple AND elegant?[/nitpick]

[Chris is me]

Originally Posted by JesseK

Keep in mind that there are KOP-based drive trains in the championship division finals every year ( I would say Einstein, but I'm not quite sure about 2006 or 2009). For these teams, the modifications to the KOP drive train are typically gearing-based (adjustments for speed, or addition of a shifting transmission), yet the basic design stays the same. The advantage these teams is only apparent when their manipulators appear to be better designed.

2009 had 121, which used the KOP frame.

Simple drive train + Elegant manipulator
vs.
Elegant drive train + simple manipulator

I think this is a false dichotomy. Simple and elegant seem basically disconnected. 25's drivetrain and manipulator were both complex but worked very well this year. Most of the 2009 robots with success were as simple as possible; the teams that won Lunacy did exactly what they needed to do to win, and no more than their capabilities. This produced very simple robots like 121, 971, and 2753.


I would just like to add a reminder that the drive is the most important part of the robot. A failed experiment costs you a season, basically. This is why most teams do drivetrain prototypes in the fall when they want to try something new.

[Dr Theta]

May I also recommend you look at the FIRST WPI resource center? There are workshop and conference presentations posted there by some of the some of the most experienced members in FIRST. I know for a fact that the 2008 workshops and conferences had some very useful power points on both drive train and manipulator design.

[JesseK]

Originally Posted by Chris is me

I think this is a false dichotomy. Simple and elegant seem basically disconnected.

I claim knowledge paradox on that one: if you remember way back to when you were a 1st or 2nd year team, the two are probably like black and white. Sure, some new teams have superb mentors or students who have good experience in building machines for similar scenarios. Yet given the original poster's tone and context, I don't think that's the case.

The divide is typically made with a sense of time: if you have 3 units of time and 1 design iteration takes 1 unit of time, would you rather iterate the design of the drive train or the manipulator given that you cannot do both? Since many first and second year teams still show up to competition without even the first iteration completely built, I'd say it's a valid analogy. If this question were posed earlier in the year, there would be extra time, but alas there is not.

[team3329]

Thanks JesseK, We are actaully a rookie team, until January comes and we enter our second year. The few of us on the team that worked this year are working on teaching those that are completely new. We are kind of waiting til the game is announced before we make any crucial decisions on design because we want to focus all of our design on the game. we are just wondering so that we can have some options open for our design. We do have some experience in the design are, just not necessarily in all of these systems. I have been trying to model our team off of some of the more experienced teams that have been very successful. But thank you everyoe for your input. Geuss thats whats so good about FIRST!