What about the RI? We are people too and like candy
At the Long Island Regional our LRI brings ME candy (and for all the RIs too).
You know where the candy is coming from…
Well I hope everyone finally got their robot bagged. For those of you attending district events, you have the ability to open your bag, under certain specific conditions, to perform additional work. Please check under Robot Transportation in Section 5 of the manual. Be sure to document your bag open on your Robot Lockup Form.
- Visibility of components. This is really an important one. The robot rules require that electrical components be visible for inspectors to see values and wire types as well legal motors etc. We will make every effort to check these items but if you make them invisible it will be difficult to get through inspection. We must be able to compare breakers to wires and check wiring of the radio, cRio, etc. I just read a team post this morning about electrical students wiring with undersized wire that smoked and melted due to being the wrong gauge.
- Wire color code must be followed. I get the complaint every year that the automotive industry uses different colors than those specified. Yes, but the robot rules are very specific. The Q&A also answered this question earlier in the season. You must use the color code supplied in the Robot Rules.
- Motors. Only the legal motors please, those listed in R29 of the Robot Manual. Fisher Price and Globe motors are no longer legal motors.
- Servos. You may use servos but they are limited by power output to 4 watts@6 volts based on the industry standard, Stall Torque x No Load Speed.
- Main breaker accessibility. This is an important one. Please do not put your main breaker behind your signage or inside a hole that my hand cannot fit through. Marking it’s location is a huge plus. When your robot sets itself on fire, we want to shut it off. If we can’t get to the main breaker to turn off your robot, it may self destruct. We may also suggest that you move your breaker to a more secure location if we think it may actually be in a position that it will get bumped off by another robot or the ball.
Some comments from the LRI at FiM Southfield for this year"
This can be a violent game. Robust bumper mounts is a must. Mounts that have been OK in the past only made it 6-7 matches before becoming quite loose or falling off.
This can be quite a violent game. Make sure your PD board and CRIO are very secure as well as strong electrical connections. We had a lot of 6 gauge power leads getting loose around the 4-8th round of matches. Around the same time we saw an up-tick in radio power plugs coming loose as well as CRIO power leads and CRIOs getting thrown around.
Cog belts can cut the ball and pop it. While many of use are used to looking for chains and sharp edges around collectors, we had a cog belt saw a hole in a ball this weekend in about 2 seconds in one of our early matches.
While FIRST Robotics Competition is not battle bots, the wide open field this year allows teams to build up a lot of momentum. The 2011 game would often start matches with 1 big hit, but this year teams are experiencing hit after hit after hit… Strain relief on electronics and proper length cables is helpful. Having guards, shields, and covers helps a lot. Contact inside the frame perimeter happens a lot. While you might earn 50 foul points, a dead bot has difficulty earning any additional points.
Well, We have week one under our belts. So here are some reminders based on what appeared over the weekend.
- Bumpers. Please remember that bumpers must be between two and ten inches above the floor when you compete. This is a violent game thus far and teams with lack of substantial fastening systems risk having their bumpers knocked out of position, torn off or fail in a hard collision. The bumpers need to be backed by structural robot frame. I saw one robot frame bent this weekend following a hard hit with another robot.
- Springs. As I listed earlier, the use of springs brings with them special problems. Not only do we need to consider safety in the event during firing, please consider what you sue to fasten the spring ends to your robot. Ty-wraps are NOT a spring fastener. These items need substantial connections to your robot frame. Should one of these let go during a loaded condition, the result is the same as a dry fire or worse. You wouldn’t design your company’s product like this, don’t use them on your robot.
- BOM. Everyone needs one, it needs to be accurate and it needs to list everything used on the robot. That means, you need to account for all the parts you made or used, all the motors, electronics, even the KOP items. You can use any form you like, but FRC provides a really nice form that comes from a spreadsheet first designed by Raul Oliviera. If you use this simple entry form, your RI will get through inspections much faster. This and bumper issues are the at the top of the list of items preventing the final inspection from occurring.
- Battery chargers continue to be a problem. The Safety Manual addresses this issue. Show up with a 50 amp charger and you will be asked to remove it under the Safety Manual, Battery Charging, on page 8.
- Since this is turning into a very physical game, I can only suggest that teams protect certain parts of their robots from damage. In particular, you might want to mount air tanks inside the frame, add additional fastening to your cRio and battery.
- While the Main Breaker should be protected as well, please don’t bury it within the robot or put it under the moving parts of your shooter. It needs to be accessible for you and us. It should be marked as well. What I often tell teams is this…
“We may need to reach your breaker to prevent further damage on the field. If we can’t, then everyone will just point while watching your robot self destruct.”
- I have talked about this before, but it is still an issue. When you bring your robot to your event and drop it off, you need to leave the B&T form attached to the robot. If you don’t bring it with you, it will delay your bag open. Most teams use a simple binder envelope that protects the forms and anything else that goes with the robot. Do not put it in the bag before you seal it. We will not open the bag to retrieve it and sign off the bag open. The B&T instructions are very clear and can be found in the Robot Transportation section of the manuals.
- Bumpers. Yes I know I listed them already, but this needs to be repeated. Bumpers need to be securely fastened to the robot frame and be backed up with robot structural frame. The KOP chassis when assembled per the instructions satisfies the bumper rules for mounting on the frame.
Congratulations to all the teams that made it through week one, and see you after week two.
Has any team been asked to dry fire their shooting mechanism in the past regionals?
It was discussed at our inspector at Palmetto. Disable vents the cylinders so we don’t load our catapult when it is disabled. We were not asked to dry fire it.
I did ask one team to dry fire their mechanism at Lake Superior, and it really didn’t seem to be a problem. We then had a different robot that got into a continuous dry-fire exercise on the field that started disassembling their mechanism. Things held together enough that parts didn’t go more than a foot or two, though.
Al, do you think you could get the powers-that-be to put a link to the safety manual on the homepage of the FRC Manual? It took a minute to find it because I rarely actually go through usfirst.org to get to the manual.
Jesse, I will see what I can do.
I am going to take a departure from my normal listing to make some recommendations based on observations over the weekend.
Bumpers. I don’t know why bumper construction is so difficult for teams. This year is proving to be a violent game and bumpers are taking a beating. Teams, please modify your design to stand up to the hard hits. I watched as a team was disabled when their bumper was ripped from their frame. If you do not use substantial fasteners, you will risk the same fate. The bumper system is designed to absorb the shock of massive robots hitting each other at high speed, exactly what we are experiencing this season. While many teams use a different cloth color to mount over a permanent color (skirts, flip over covers, etc.) few are considering the effect of a hard hit has on this method. You should use some positive attachment to prevent the fabric from coming off in a collision or from slipping and allowing loose fabric from dragging on the floor. You have spent a great deal of time making a nice looking robot. Invest equal effort in building your bumpers. While bumpers in the corners are legal, this might not be the game that best utilizes that design. It seems that teams with full bumpers are surviving the best.
You have a choice of fabric available to you, but even the 1000 dernier Cordura is getting damaged. Don’t skimp on the fabric, get the “good stuff”. Two colors that closely match the FIRST Logo colors are needed. You need to add your team number to the fabric. There are several methods that you can employ for that, including number kits available from several locations. Expect that the numbers will pull off and have spares ready to apply.
Remember that they must be fully in the 2" to 10" zone above the floor when sitting on a flat floor. If you have allowed some slack in your fabric, expect the pool noodles to sag. When they go out of the bumper zone, you are in violation. A quick check is a boot toe should fit under the bumpers. If you have checked yours with a tape measure than calibrate to your own shoe and insure that every match you are within the bumper zone.
And lastly, if you use a method for attachment that takes your team 30 minutes to remove or to remount, you really need to think about a better method to attach them. The rule of thumb of one person and ten minutes should be your starting point for attachment design.
Good luck everyone.
This is a different discussion, but teams really need to remember that they have an e-stop button and that there is no real penalty for using it.
This particular team could have cut the damage to their shooting mechanism in half if they had e-stopped before the field staff got to their driver’s station and gave them a hand with pressing the button.
I saw similar incidents more than once at Lake Superior. If your robot is damaging itself, the electronics fall out, your battery starts dancing, or your robot is no longer vertical, hit the button!
I requested one (motor-powered), just to verify safe operation when empty.
The result did no damage other than to shake a battery loose that I’d already suggested be further secured.
Today’s installment will be referencing the Team Updates.
- Teams should regularly check the team updates, keep a copy handy with their other manuals and check them against their own robot designs.
- Inspectors will use any Team Update that is current for that week of competition.
- Any update that is a change in robot rules will be reflected in a revision of the Inspection checklist. We are currently at Rev B, reflecting changes in the stored energy warnings and lockouts and for the change in Pressure Relief Valve mounting.
- Team Update are planned for Tuesdays but other immediate items may cause an update at any time. Watch here on CD for alerts and check the FIRST website often.
- The Team Update for Tuesday, 3/11/14 has repeated a blog post from last year highlighting safe practices for using pneumatics and in particular the white storage tanks.
- Yesterday’s Team Update also added some language to clarify the withholding. “This static set of items may only be brought into the Pits when the Team initially loads in at the Event. Items made at an Event do not count towards this weight limit.” Teams have thought that they could continue to bring items to an event throughout the course of the event as long as the total weight for all items did not exceed 45 lbs. This has never been the case so this added language is just making that clearer. You may bring items in at team load in.
As a reminder (since this has been an issue the past two weekends) you are allowed one and only one robot at competition per R1. If you feel a need to bring a second robot for some special reason (demo, sponsor display, etc), you must receive prior authorization from FIRST HQ to do so. You may not bring a second robot to scavenge for repair parts. Remove the items you wish to use for repairs prior to the event.
Am I correct that this means zips ties cannot be used to structurally secure surgical tubing? What would be considered appropriate? (I’m remembering this thread, that was principally centered around zip ties.)
You can secure the surgical tubing to itself (after you have wrapped the tubing around a structural part of your robot) using ty-wraps as there is very little load on the ty-wrap when the tubing is in motion. You don’t want to use them in place of hardware (as a tie bar or link) to secure one end to a stationary part of your robot. The dynamic loads could cause them to fail.
Thanks, Al. Understood; this is the way we use them.
I prefer Rapid Unplanned Disassembly.
We just finished the Dallas Regional and the robot on robot contact was pretty rough. We are thinking of adding some strength in the bumpers. Can the CD community help us understand on the limits and intentions of R21? We know we need to query the GDC but I’m not sure how to phrase the query (yet).
So the angle to hold the cloth must be aluminum, correct? No steel? But we could use 7071 or 7075?
Can we interconnect the top and bottom angle pieces? We know many top tier teams do this. But is it contrary to the rules? I’m thinking a solid 5"x1"x<length> u-channel is problematic for an inspector. But perhaps if there are just some small finite number of inter-connections between the top and bottom angle that might be OK. So my last query is how much structure can there be between the top and bottom angles before it causes inspection problems.
Most of what you see behind the bumper is consider part of the mounting system for teams. Texas Torque and my team both used sheetmetal parts as part of our bumper assemblies this year that become part of the mounting system for the bumpers. Torque’s are an entire c channel like you describe. We use a z- bend on our top rail and normal 1" angle on the bottom.