Re: Drive Systems... ...The FIRST Arms Race?
 

Hmmmmm, I have a few thoughts here:

1. Lots of motors in the kit means cool off season projects for many teams who can't afford extra purchases. They also mean spares for swapping the FIRST way. It certainly adds to the whole power budget decision-making thing too which is a challenge in itself.

2. I don't know about too much drive train or restricting use at all. Last year I had a rookie team that used a grand total of five motors and was pretty competitive by the off season once the bugs got worked out. This year the team is up to seven motors and that was a stretch for us. Do I feel we will be less competitive than those with custom or expensive gearboxes? No.

3. I'm all for any motors in the kit we can get. Doesn't each motor represent one more potential supplier? Isn't that one way FIRST grows? How can you ask a supplier to donate a ton of stuff then tell the teams that they can only use the motor for certain applications? Doesn't that squelch creativity and discourage potential suppliers?

4. Why are people still talking about aftermarket gearboxes in a negative way? Hasn't that been done to death? More competitive, moving robots means a higher level of exposure to the public means we are closer to achieving FIRSTs real mission. How is that bad? Without the AndyMark single speeds my rookie is using, they'd be carrying open transmissions to a regional waiting on new plates.

5. With all due respect, how can anyone equate or value levels of "inspiration" by what motors are in the kit? The inspiration comes from the interaction between students and mentors, teammates, and interaction with other teams. The tools one uses to inspire an individual is up to the "teacher".

I'm glad we have so many technically inclined folks that help the program move forward, I honestly do, but if we get tied up in kit analysis we might forget there's a student that needs our attention.

Namaste...

Re: Drive Systems... ...The FIRST Arms Race?
 

one thing that has not been brought up, which i'm probably going to get hounded for on two counts, more on that in a few. one way to limit extremely powerful drive trains would be to go to a smaller battery, one that would need to be conserved to make it through a match, so you could go for a powerful drive train for a short period of time, or a less powerful one for a longer amount of time, perhaps extending the matches so that this became a factor more. I think the innovation that would result could be very interesting to watch. Now, the two counts on which i'll be hounded, 1. FIRST just changed the battery, so for those teams that have purchased multiple for extras, this wouldn't be too nice, and the second point, many people, including me, don't like to change the battery every two minutes during testing... we have some '05 batteries that have been through competition twice, and two off seasons, and last for about two minutes before being useless, with lower powered batteries, this would become a reality even when the batteries were new, anyway, thats just my $.02

Re: Drive Systems... ...The FIRST Arms Race?
 

The Tim Allen mentality is what I think Joe is referring to. " More Power". During the off season it seams that most teams that were doing off season projects focused on drive trains. How many teams worked on manipulator development, sensor integration, or autonomous navigation? First could control the drive train arms race with a very simple rule. Limit the energy, Make it precious and expensive. ( like what is happening in the real world). Each team is allowed 2 batteries at the competition. On practice day each team submits 2 batteries at inspection and their serial number is recorded and a permanent label is affixed. Those are the only 2 batteries allowed for the entire competition. Teams can do what ever they what with the motors and mechanisms, but the energy budget is limited. If a team gets to the finals and is forced to compete with dead batteries then they pay the price for poor energy management. This generation of kids will have to face the looming energy challenges in their life time. First can help focus them on this social issue. The other way to take the focus away from the arms race is to make the autonomous period longer and more important.

Re: Drive Systems... ...The FIRST Arms Race?
 

Just a couple of thoughts -
I believe that some parts of the robot are designed to meet the specifics of the game or the playing field. The reality is, that the drive systems can almost always be re-used from year to year, while end effectors almost always cannot.

Therefore, many of the off season and season2season improvements are focused on the drive system. With an unlimited supply of motors and alot of time - it is natural for this to happen. I'm actually surprised that nobody has developed a drive system using every motor in the kit.

I like some of the suggestions that Joe has made. Yet, I also like the increased variety and number of motors to choose from.

I think encouraging the management of power could be as much a challenge as managing size and weight. Learning to understand and deal with all of the challenges, could be very Inspirational (it simply depends on it is approached).

Alot depends on where you want to focus your attention on, and where you can save time and energy by re-using what has been proven out already.

My favorite suggestion to rebalance the reuse and elevated effort for more and more powerful drive systems, is to change the playing field such that the drive system contact surface is either slippery or moves under load. Do they make portable flooring for ice covered surfaces!

Great discussion

Re: Drive Systems... ...The FIRST Arms Race?
 

We learned our lesson on this last year. Too many motors on the robot meant not enough power. We made a solid run at Nationals but battery power was a constant issue.

Ironically we had only a 2 motor drive base. I felt we were penalized for focusing on an elegant shooter because we were routinely disturbed by box bots. :(

I agree with Dr. Joe that something needs to be done. I was around in '96 and had the pleasure of building a squat little 70lbs. bot. It was a blast. I remember how challenging it was to utilize the available motors.

Pneumatics were also a rich source of power......I'd argue that nowadays they're more or less irrelevant. We haven't been able to justify the weight for three seasons.(which by the way is a product of so many motors. why waste weight on a pump, spikes, and solenoids when you have a plethora of light high torque motors to use.)

I'll never suggest that we use rules to govern how robots are built. I feel that we have too many rules as it is. Perhaps a robot class system is what we need. A stock class for entry level players and an unlimited class for the big dogs.

Teams who chose could compete in a stock class for a year or two with more access to off-the-shelf components and rules that forced them to run a stock chassis.....thus forcing them to focus on the creative portions of the game. The next year they could register to play in the unlimited class where they would have less access to off-the-shelf parts...forcing teams to go custom. Pair this system with challenging playing fields that demand creativity and we're good to go.

Many of these issues stem from the fact that veteran teams have a potential advantage over enrty-level programs from experience alone. FIRST polices it by giving young teams access to veteran team technology and dumbing down the playing field. Perhaps a class system would solve all of these problems.

Afterall, it isn't inspiring for my students to build an amazing machine just to see it bashed and beaten apart in a free-for-all melee. For the record, we jumped back on board this season with a 4 motor shifting drivetrain and tank like construction.

Thanks for your valued input Dr. Joe.

Re: Drive Systems... ...The FIRST Arms Race?
 

Funny you should mention this, the new batteries this year have a significantly lower short current (90A) than the old batteries (240?A).

Re: Drive Systems... ...The FIRST Arms Race?
 

Darn you beat us. We have 6.

I think the drive train arms race stems from a few factors I haven't seen mentioned yet. Simply every year you have to have a drive train. Therefore when teams do offseason development projects it winds up being the obvious choice because you'll be able to use some portion of the project the next season no matter what.

Another factor that caused the development of these drives in the first place was the weight of the goals in 2001 & 2002 that teams needed to move. That was followed by a completely defensive 2003 game (I blame this squarely on the ramp bonus being too high) where teams had to push to be king of the hill. Teams that were around in those years had to build stout drivetrains and didn't want to give them up once they got used to the speed and power. New teams would see these drivetrains and emulate them getting us to where we are.

Oh and there's the fact robots can weigh about 20 lbs more (bumpers & battery rule changes) now than they did 2004.

My solution for the last couple seasons has been go smaller and lighter to get away from these issues, but every time I've brought it up people seem violently against it because they don't want to give up what they've got. We've grown to expect more in the kit every year without having to give anything back, and that attitude needs to change for anything to happen in this arena.

Pete

Re: Drive Systems... ...The FIRST Arms Race?
 

We're using three motors and two cylinders. Hopefully it will be enough. We could add two more CIMs to the drivetrain if needed -- maybe.

Re: Drive Systems... ...The FIRST Arms Race?
 

While I agree there is most definitely an "Arms Race" occuring in FIRST's drivetrains (as well as just about every aspect of the robot, more on that later), I think the game becoming more defensive is a myth (again, more on this later).
I believe the drivetrain escalation can be traced to a single moment, or rather a single game, in FIRST history. 2002, Zone Zeal. While certain factors emerged earlier, especially with the creation of alliances in 1999, 2002 began the un-reversable development of this "arms race". Zone Zeal was a game based almost entirely on [mobile] goal procurement, control, and placment (tasks heavily dependent on the drive). Not surprisingly, the fastest and strongest bots accounted for a majority of the victories. This is perhaps best demonstrated by the legendary drivetrain of Team Hammond that year. 71 produced what is widely regarded as the strongest drivetrain in FIRST history (capable of towing itself, 3 quite heavy mobile goals, and multiple opposing robots on it's slow march across the field), and it capped it's domination with a win at the 2002 Nationals. Not surprisingly, we also saw the first backlash aginst power in 2002, as FIRST also saw the creation of it's first holonomic drive. 857's killough drive made monumental splashes in the FIRST community in the years to come, in part, leading to the massive amount of Mecanum drives revealed for this years game.
The arms race is without a doubt here, but more defensive games, I'd couldn't disagree more. Early in the build season, I decided to drag up some old Torroid Terror (1997) tapes to watch the last game using inner tubes. What I saw was a very defensive game (for the most part), with only a very few elite teams who could produce significant offense. Even the human players got in on the defensive action, as they threw tubes to try and knock tubes out of opposing robot's graspers. It was especially surprising considering the game was 1v1v1, so placing a defensive commitment on one team, allowed the other to pretty much have a free chance to score...but it didn't matter, defense was common. In 1998 there was even a match where the placebo won (each team started with some balls in the goals. The two competiting bots descored eachothers, and never scored, leaving the placebo's starting points enough to win the match). The same can be said for even earlier FIRST games as well. In 1993, one bot would detach what was essentially a wall that would sit in front of the goal. That factor has applied to every game in FIRST (aside of the 4v0 2001 game). What has happened was the creation of alliances in 1999, and the change to 3-team alliances in 2005. Both of these allowed for the evolution and creation of "niche" bots. These "niche" bots fill very specialized and specific roles within alliances, and defense is one of those such roles. During the pre-alliance era, it was impossible to win a match on defense alone (aside of 1998, where each alliance started with 6 points from balls located in the troughs at the beginning of the match), but now an individual team within an alliance can focus on defense and let other bots do the scoring. Games are no more defensive than ever, teams are just being more physical.
I don't see this drivetrain race as a bad thing, in fact I enjoy it. It's not unique to the drives either. Teams are making more complex turrets with greater degrees of rotation, longer arms with more joints, more efficient end-effectors, lighter and lighter components, and more advanced coding based in greater sensor input than ever before. FIRST is growing in terms of what teams can do, and the amount of teams. As the amount of teams grow, and the amount of experience expands, innovation and improvement become essential to be competitive. And none of this "arms race" stifles innovation. Just check out 1857's "spine" manipulator.
I agree that we probably get a few too many motors in the Kit of Parts (I think 11-12 should be more than any team needs). 116 is only using 6 motors this year, and 4 of the so-called "powerful" motors are sitting in our shop while the robot is on it's journey to Richmond.

Re: Drive Systems... ...The FIRST Arms Race?
 

I don't believe we should limit the battery. I have enough trouble finding a charged battery to put into the bot before a match anyway, and last year we had 6 of them circulating.

I don't believe we should limit the number of motors, either. This year we have two motors on our robot (4, counting shifting servos). While we didn't use them, its nice to know that we could if we ever wanted to.

I don't think we should limit "energy". That would make for a lot of matches with robots sitting there energy-less and cold.

I don't think we should impliment anything beyond the current limitations:
-We have Six weeks to build a robot.
-It has to be under 120 lbs.
-It has to fit into a relatively small size envelope.
-It has to use only one relatively small battery.
-we have to limit ourselves to the motors given in the kit (while there are a lot of 'em, they are not all "quality" motors)

^That is a lot of limitations already, why add more?


While defense may be seen as the thorn in an "elite" team's foot... It is the only thing possible for some teams.

Not all teams can build a manipulator that can score consistently.

Not all teams can build a functional ramp.

Defense is for the teams that can't do those things; it is the only way for some rookie teams to remain competitive. It is a way to fight back against the ever-growing population of teams that can create scoring monsters. It is the always attainable aspect in any years game that make FIRST fun for everyone involved and not just the "elites", and it adds one more task for the "elites" to design around.

And the issue with Defense making for less interesting game-play? I don't think it has much bearing at all. There was nothing more exciting than watching an offensive bot sink 4 balls last year, and then shoot the rest into a wall because they were pushed by a rookie bot, or watching an offensive bot be pushed all the way across the field by a defensive bot.


Just some thoughts,

-Cody C

Re: Drive Systems... ...The FIRST Arms Race?
 

FIRST has stepped up the competition over the years, obviously. Robots are getting more complex, faster, and more powerful. This brings the demand for new motors, and more of them. However, I like to think of the motors in the kit like a set of watercolors, with the robot being the canvas. Just like artists don't use every single color availible, robots shouldn't need to use every motor given to them. It's quality, not quantity, for some teams that is, anyway.

On the other hand, some teams have the knowledge, resources, and man-power to implement every single thing given to them, which is how I think it should be, to an extent that is. Figuring a way to use less motors to do the same task makes things much simpler and easier to accomplish in a 6 week period. However, theres nothing wrong with modifying a tried and true design with more motors to make it more powerful (like a gearbox), thus, putting you ahead from other teams. After all, this is a competition.

Re: Drive Systems... ...The FIRST Arms Race?
 

I feel From what i have seen over the years is technology of the robots has gone up alot from 2000 to now. i feel that the biggest change in First history would be the change in 2005 with the 3 on 3, this change to add another partner, gave teams a chance to be carried. plus you had more to worry about with 3 other robots to face and along with 2 other robots to not crash into. also the games have been more thinking about what other teams are going to do besides playing your own game. the Drive trains will get better and stronger and along more robust. my ideas with companies that offer some premade gearboxes, or wheels helps out teams that don't have enough money or have a lack of engineering support. i know from this year we lost our sponor and the engineering to go with the company and Andymark gearboxes helped us when the banebot plates started to warp on us.

Re: Drive Systems... ...The FIRST Arms Race?
 

The way i see it, the mathematical limits to your pushing power are all that FIRST needs. Seeing as your pushing force is only created by the force of friction, you can do two things to increase your pushing power, assuming you have used sufficient motors and gear ratios. Increase your normal force (weight) and increase your coefficient of friction (tread). In theory, the only thing that matters is the type of tread and not the suface area, but in practice a large surface area is at least slightly better. As you increase the suface area of the tread, you make it harder and harder to turn, untill you reach the point where you need some sort of actuation to reduce surface area for turing purposes, or you just cant turn at all. A robot that cant turn or that has significant trouble turning is about as useful on defense as a rock, assuming that there are multiple positons that it is possible to score from.

If you didint feel like reading the giant paragraph above, to summarize:
The limits on total weight and the fact that you cant have infinitley sticky or infinitely big tread limit robot pushing power enough, there is no need for FIRST to do anything.

Re: Drive Systems... ...The FIRST Arms Race?
 

Maybe if you knew your battery wasn't as strong as years prior, you wouldn't design your strategy and robot around stalling a few 350 Watt motors while trying to "push" other robots for the entire match.

Re: Drive Systems... ...The FIRST Arms Race?
 

I don't agree at all about having fewer motors. Though I do agree that drivetrains have become more complex, the KOP has done what it's supposed to do: give every team an opportunity to build a DRIVEABLE robot. I remember hearing from 2003 about how poorly and flimsily our robot drove. The KOP has been the great equalizer. The inclusion of links and other stuff to omni-wheels has given more teams the chance to compete at the same level.

Is there going to be a drive race? Yes. But what do I think?

I think that too MANY motors can lead to too many problems should something go wrong. And pushing well is not necessarily about how many motors are in the robot. It's about traction and control. As for leaving the 17 motors, I would add more. Remember, Dean Kamen intended for there to be too many parts so teams would have to make ENGINEERING decisions on motors.