Re: 816 - 90% Complete (Video inside)
 

What was the lower link previously? PVC?

Our machine shows a lot of the same characteristics that yours does and it seems like we've taken a lot of the same steps to mitigate the problems. I've been considering replacing the lower link with aluminum or fiberglass, but we see a lot of elastic deformation in that member and I'm worried that the replacement will plasticly deform instead of stiffen things up.

Re: 816 - 90% Complete (Video inside)
 

Dustin, this robot is god awful...It has nowhere near the respectable amounts of orange and blue yet. Get on that.

Re: 816 - 90% Complete (Video inside)
 

looks good 816. I could have sworn I saw a similar gripper somewhere around our shop. I can only hope ours works as well as yours does. Practice it up and add some more orange and blue and you should be good to go this season!

Re: 816 - 90% Complete (Video inside)
 

I think cycle time will be a big deal, but I also think that there could be serious benefits with creating a system that easily obtains game pieces from the human players:

1. There is not contention for the tubes dispensed by the human players

2. Those tubes are ALWAYS in the same location, with little to no variance, and can be fed directly into a robot's gripper with a significant amount of precision

I feel like with a large number of teams, there might be something in taking the extra few seconds to go to the human player's station because it has the capacity to save lots of time over trying to acquire a game piece that is on the floor with the drivers having only an obstructed view of it. At the same time, I'm fully aware that there will be teams with a human player who can throw game pieces consistently to a spot, and those robots will be able to immediately pick up and place the tubes. I think, though, that most teams will find some balance right in the middle, between slow floor pickup and reliance on the human player.

Re: 816 - 90% Complete (Video inside)
 

I see 30 seconds as unrealistic as there will be 5 more robots on the field and some of those will be playing defense. I believe 1 minute cycletimes will be closer to the norm.

I also believe that throwing in the tubes will only entice your opponents to take the tubes your human player has 'provided'

Re: 816 - 90% Complete (Video inside)
 

Here I disagree with you. I think there will be a good number of teams who will be able to hit that 20-40 second range easily.

Here, though, I entirely agree. I think that throwing tubes onto the playing field will be a brilliant strategy...sometimes. At other times, I think that it would benefit teams more to deliver directly to the robots.

Re: 816 - 90% Complete (Video inside)
 

Madison, the original lower link was 1-1/4" Sch 40 PVC. We noticed a lot of elastic deformation under load, and our operator complained about the amount of "bounce" while lifting and moving. We replaced the lower link with a 1-5/8 OD Aluminum tube with a .109 wall and that has fixed all of our issues.

I noticed that the PVC arm had approximately 1/2" of an outward bow in the center after it was removed and showed that it had begun to stress and discolor. There is no doubt in my mind that the link would have broken at some point in our season, I'm just not sure when.

Orange and Blue will come eventually, I'm more concerned with Mini-Bots at the moment. Lol.

Re: 816 - 90% Complete (Video inside)
 

Best of luck to 816, its fantastic that you all have a week to practice driving and programming. Thanks for posting a non-cryptic video.

Re: 816 - 90% Complete (Video inside)
 

I guess we'll just have to wait and see.

By my numbers an alliance will average 3-4 tubes per match, by your numbers an alliance will average 10 tubes per match.

Lets see who's closer ;)

Re: 816 - 90% Complete (Video inside)
 

Thanks Barry. This video is actually from last Wednesday or Tuesday night, so we've been up an running for nearly a week now. We learned in 2008 that having at least a week or two to debug is extremely important if a practice bot isn't available after ship so we work extremely hard to get our design finalized early.

Oh, and to answer your question posted on the video, we were inspired by the original Orange 4-bar. (1902 in 2007) :D We can only hope to have the same success that 1902 had that year.

Also, I'm really glad that people found this video so helpful for strategy discussion and to get a feel for the game. We have more videos that will be up later this week, we just can't exactly reveal the completed robot before the sponsors and team families see it. ;D

Re: 816 - 90% Complete (Video inside)
 

816, looks like you're most of the way to being a very competitive robot! I envy that you'll have a full week for programming/driving practice/etc. That could really be the difference.

Without defense, it looks like there'll be many teams that can do a sub-30 second run without defense (816 looks capable). With defense, I don't think this would balloon up past 45. For some teams it could even still be under 30!

Re: 816 - 90% Complete (Video inside)
 

Looks good like your tube intake

Re: 816 - 90% Complete (Video inside)
 

Out of curiosity -- did the P60 failure you experienced happen before or after you replaced your link with aluminum?

Our gearbox is, so far, doing okay, but we're also investigating an aluminum replacement and I am wary that the added rigidity might cause or accelerate a failure.

Re: 816 - 90% Complete (Video inside)
 

Fair enough, I still think a lot of teams will be able to score a tube in around 30 seconds, especially come Saturday at most regionals.

This is where your human player strategy is key. The human player absolutely cannot throw the tube too early. Doing this leaves the tube open to being stolen by your opponents. A truly skilled human player will time his or her throws perfectly so that their alliance's robot is ready to pick up the tube the second it lands. Human players should definitely be factored into scouting this year as an alliance with two skilled human players can help tip the scale in an elimination match.

Re: 816 - 90% Complete (Video inside)
 

Madison, the gearbox failure happened during initial testing of the Aluminum link. That being said, we were never able to work the PVC link as hard as we were the Aluminum link because we were afraid that the PVC was going to snap. It's a bit hard for me to say that the aluminum caused the failure, but at the same time it's difficult for me to say that the aluminum didn't cause the failure.

Sorry I can't be of more help.