Re: Is Stronghold the roughest game yet?
 

And bumpers. There were basically 3 years worth of students on teams who had never had to build a robust bumper. (Let alone compliant with the rules...)

Re: Is Stronghold the roughest game yet?
 

This statement confuses me. Surely students who competed in Aerial Assist would have some memory of how to build robust bumpers.

Re: Is Stronghold the roughest game yet?
 

A one year gap is a lot of time to forget.

Re: Is Stronghold the roughest game yet?
 

It really is, and plus Aerial Assist simply didn't have that much brute force on either the frame or the bumpers (I've been told). Most of the bumpers I saw falling off, happened when the robot hit a defense the wrong and got stuck.

Tell me, (I wasn't a part of aerial assist) did bumpers fall off often in aerial assist?

The portcullis managed to break the 3/16 polycarbonate rails we intended for it to slide on when our driver hit it at almost full speed. It went up, hit its stops hard and then Newton took over with one of those pesky laws. Snapped the poly right off.

Re: Is Stronghold the roughest game yet?
 

Took a hit so hard at champs in AA that the drive rails on our WCD bowed outwards and all the rivets mounting the drive rails to the bellypan sheared.

Re: Is Stronghold the roughest game yet?
 

I'm not share if this belongs here exactly, and if it doesn't, feel free to let me know, I'm new to chief Delphi- anyways, a few problems that we have had this year:

Generally, the robot is actually holding up pretty well this year- we only had a few problems, and only three of them actually effected our matches

-aluminum rivets on the front of our bot all suffered absolute failures, we replaced them with steel rivets and had no problems(no effect in matches, just a really bouncey electrical board)

- we burned out a CANTalon somehow, (we think that it was a lemon) and it took down our entire CANBus. Fortunately we were on the batter when it happened(we did end up missing a match while we tried to find which component actually burned out, everything still had its lights on so we had to manually test each part)

-A bearing on our climber failed, causing the climber to stop working

-Our robot uses one shaft to rotate itself above the low goal. We use a 3/4" water-hardened steel shaft to do so. We twist it. It actually twists about 60° every 12 matches, when we usually swap a new one in- but for MSC we didn't swap it out at all, and we had no problems with it

- CTRE's 18 gauge ferrels don't properly fit our 18 gauge wire, so we switched to 16 gauge ferrels and crimped them tight... Only problem is that the electronics seem to put too much pressure on them, causing them to break off inside of our Power distribution board, pneumatics control module, and voltage regulator- irreparably. (We lost radio power in a match due to that one)

Re: Is Stronghold the roughest game yet?
 

Our robot has been roughed up a lot...

-The camera kept falling under our mount at St joe. Fixed by moving it back from the mount.

-The outer walls on our aluminum tubing began bowing out in several spots. Fixed with steel brackets inside tubing.

-The pvc guides for our shooter broke out during a match at St joe... Replaced with aluminum for traverse city

Aluminum piece of customized kit chassis under battery bent after every finals match in st joe... Replaced with steel for traverse city

Hubs for our polycord belts on our intake broke from hitting the low bar. Made a bracket to protect it...

-main shooter backplate began to bend slightly at traverse city and then failed completely when our guides hit the berm at MSC... Replaced with our firmer backup. (But have to lift shooter when crossing berm... Who knew it would be our hardest defense at states?:yikes:)



That's all I can think of right now but we fixed every issue we could and tried to make sure it couldn't happen again. :D

Re: Is Stronghold the roughest game yet?
 

Finally did a full inspection of our bot today. Apparently some how, somewhere the transmission on the left side completly cracked and one of the 3 motors was dangling loose... I suspect if we had played even one more match, something bad would have happened.

Re: Is Stronghold the roughest game yet?
 

We used what we called the plow on our robot to have the porticulus slide on. It was made out of 1"×1" with 1/8" wall square aluminum and that still bent and minimum speed. It wasn't major bending but that part of the arm bent roughly 1.5" back by the end of State.

Re: Is Stronghold the roughest game yet?
 

You should watch some of our matches from 2014 then, I would wager that we had the fastest robot on the field that year. We were almost max weight and nearly all of it was less than a foot off the ground, I don't care if you have good bumpers when a 140 pound robot slams into you at 2% the speed of sound(Yes really) you will feel it. The pool noodles went completely flat in the corners, the maple plywood shattered several times.

This year is still worse though.

Re: Is Stronghold the roughest game yet?
 

This is the roughest game since 2006 - the last year before bumpers were added.

Robot to robot contact cushioned by bumpers simply isn't that nasty. Negative acceleration over the distance of bumper compression involves less g-force than a robot slamming into an essentially unmovable steel barrier with a portion of their chassis. If you add in the violent landing that occurs - even coming off the chili fries - you have a game that would test any robot.

In addition, I have yet to see a robot to robot interaction foul called this year. In 2014, interaction inside the bumper zone was very frequently flagged. This year it is not flagged, and some tippy defensive robots have spent a good portion of their match time landing on top of other robots.

In 2006, it was possible to have a chassis to chassis interaction of two robots travelling full speed in opposite directions. Robot interaction fouls were rarely called. I would argue those collisions may have had greater forces involved than this year. However, they were rare compared to defensive crossings.

Re: Is Stronghold the roughest game yet?
 

You haven't been paying attention to chief delphi at all have you :D There have been several several fouls called, and several red cards called as well for robot to robot interaction.

Re: Is Stronghold the roughest game yet?
 

Interesting. It must be as widely varied as the tipping fouls are. There were a couple bots at Michigan Champs who would wheelie when accelerating and then slam down on top of other bots and I never saw a single foul called - even when pieces went flying.

Re: Is Stronghold the roughest game yet?
 

Stronghold is certainly the roughest game in recent memory; I'm not qualified to say anything about the early years. It was clearly the most brutal terrain since Breakaway. IIRC, a Breakaway bot could opt to go under those walls; in Stronghold, there was no (legal) way around (under) the opposing defenses, and crossing most defenses twice was actually a Ranking Point game objective (breaching), and doing many crossings is usually essential to another (capturing the tower). All of the reliable shortcuts and workarounds to robots directly crossing the defenses were plugged by game rules.

I don't recall nearly as many lost bumpers in Aerial Assist. There were massive bumper-to-bumper hits - harder than I've seen in Stronghold. This is because the field had no obstructions except the four corner goals. However, this force usually drove the bumpers INTO the robot; Stronghold has many more cases where bumpers are exposed to high shear forces. This was the first time since Breakaway that bumpers were regularly slamming vertically into field elements. Further, in Aerial Assist, teams mostly tried to lower the bumpers as close to the ground as possible, to make picking up that 24" ball easier. In Stronghold, most bumpers topped out between 11" and 12" to make it easier to get over the defenses (and in many cases the boulder intake is BELOW the bumpers this year).

Between the many angles of collision and the high number of "bumper rookies" there were bound to be a lot of bumpers on the carpet. Even veteran teams were short on bumper tribal knowledge -- our fifth year team had four students who played both Aerial Assist and Stronghold. Two did wiring and two did programming for Aerial Assist - none touched a bumper except to help swap them out while on pit duty. Our bumper knowledge was from mentors. Our returning technical mentors had never dealt directly with bumpers in the past except as something to work around, though we do have a NTM who took part in bumper sewing (though not mechanical construction or mounting) during our early years. Without the preserved wisdom of CD, we would have probably been in the "bumpers on the carpet" crowd.