FRC Robot Inspections (2010) WPI FIRST Regional Northeast Utilities FIRST Connecticut Regional Mike Betts 2/20/2010 Edited 2/26/2010 Note that some opinions are those of the author and may not reflect those of FIRST or other Robot Inspectors.

The Role of Robot Inspectors To help teams get to the playing field in a safe and equitable manner.

Robot Inspections

Robot Pre-Inspection (Voluntary) There will be no mandatory safety inspection this year. Any team may ask for a quick safety inspection before going to the practice field. Is the Battery secure? Is the 120A Circuit breaker in an easily accessible location? For robots using pneumatics: Is the PRV present and the vent valve easily accessible? For robots using stored energy devices that are “charged” before the match: Is there some sort of safety interlock device preventing accidental discharge or firing?

Robot Pre-Inspection (Voluntary) This inspection should last less than two or three minutes. Robots passing this inspection will be given a sticker (shown) which can be proudly displayed on their robot to indicate to your neighbors in the pits, the FTA, queuing and field personnel that the robot meets a modicum level of safety.

Robot Pre-Inspection (Voluntary) The FTA may decide to make this inspection mandatory for any robot or for all robots at his or her discretion. If a team wants the exception granted by <R97>, the stored energy inspection bullet will be mandatory before robot inspection for size and weight. This sticker will allow a robot to step right up to the sizing box and scales with no delays.

Network and Encryption Inspection It is my understanding that there will be a dedicated kiosk for this inspection. This kiosk will not be staffed by robot inspectors. It is my understanding that a robot will not function on the field if it does not have: The correct cRIO firmware. The correct Driver’s Station software installed. The correct network addresses. The correct encryption key. I do not have any further input or information on this subject.

Robot Inspections I anticipate that robot re-inspections will remain as they were last year. More on this later. The formal robot inspection process is going be different. It is going to get faster…

Faster Inspections My goal is to have all robots to have completed inspection by 12:00 (noon) on Thursday. This requires a change in culture. Many teams wait to start inspection because they are able to and they know that they can breeze an inspection late Thursday. They want to make a lot of changes before inspection.

Why The Rush? On the FRC Blog (9-29-2009), Bill Miller indicated that “FIRST is striving to ensure all FRC Regional Events have a minimum of 10 qualification rounds. Traditional FRC Regional Events may only have a half-day of practice rounds on Thursday before qualification rounds begin.” There are eight two-day regional competitions this year. These trends will continue… Inspections need to be finished early on Thursday.

Why The Rush? In addition, many of my inspectors are also team mentors. They will appreciate being able to rejoin their teams as soon as possible. Lastly, there will always be a few stragglers (usually rookies). Hopefully, I will be able to concentrate on their needs and allocate the resources they require in a much more focused manner if all the other teams have passed inspection.

There is Nothing Special About Thursday… After you have completed inspection, you are encouraged to continue working on your robots through the end of the competition on Saturday. Merely come up to me for re-inspection. Let me know what you changed. In most cases, no other action is necessary.

Veteran Teams Teams who have participated in a previous 2010 FRC regional competition will be met by a robot inspector while they are uncrating their robot and invited to begin their inspection immediately. Teams who decline this invitation will get a visit from me personally. Next, veteran teams (team numbers 1 through 299) will be invited to start inspections. Yada, yada, yada… You get the idea… I am counting on the veterans to set an example for the rookie teams and make this work. If your team is ready to start, you need not wait for an invitation. Step right up…

The BOM The number one reason why teams do not pass inspection on Thursday has constantly been not having a Bill of Material. While your team is uncrating the robot, please send one team member up to the inspection desk with a thumb drive containing your Bill of Material (BOM). Your file will be copied into a common directory and renamed FRCxxxx_Hartford.xls (where xxxx is your team number) IAW Team Update 11.

The Inspection Process Submit your Bill of Material (BOM). When ready, bring the robot up to the inspection station. Your robot’s bumpers should be removed and carried (along with all fastening hardware) separately. Your 12V battery should be removed and left in the pit. Your operator's station can be left in the pit. At the Inspection station: If required: Safety check as per <R97>. Size check (size box). Weight check (scale). Both the robot and the bumpers will be weighed separately and both weights recorded. Frame perimeter check (level). Return to your pit Reinstall your Battery and Bumpers You will soon be visited by two inspectors.

The Inspection Process After your team has returned to the pit, your inspectors will review your BOM and then visit your pit. The inspectors will want to communicate directly with the students. Mentors can help by stepping back and give the team room to work. If the inspectors wish to talk to the mentors, they will ask the students to invite them over. The inspection will roughly follow the “2010 Inspection Checklist”. The students will feel more comfortable if a mentor has taken them through a dry run before coming to the competition. After completion of the check list, the students should call their mentors back to the pit and explain what needs to be done (if anything). The inspectors will stand by to answer questions. After all parties have a clear understanding as to what needs to be done, the inspectors will return and begin this process with another team.

The Inspection Process After your team has corrected or addressed the issues, send a student to the inspection station and let us know that you are ready. As soon as an inspection team becomes available, they will come to your pit and re-inspect the outstanding items. Note that the inspection team need not be the same as you started with. Sometimes this process takes more than one iteration.

The Inspection Process Review the inspection checklist with the students, mentors and inspectors. The lead student and lead mentor both sign the checklist where indicated. The final inspector signs the checklist where indicated. The inspector gives the team a sticker for their robot and initials it. The color dot is usually reserved for Saturday re-inspection.

The Re-Inspection Process (Random) The FTA and/or Head Referee can request a re-inspection at any time. This is usually the inspection of a specific component or mechanism and is handled on a case by case basis. If at any time during the contest you modify your robot, a team should request a re-inspection. Let the inspector know what you modified. Re-inspection after modification may require a robot to be re-weighed or re-sized at the discretion of the inspector.

The Re-Inspection Process (Saturday) On Saturday, at the end of your last qualification match, please bring your robot directly to the inspection station for re-inspection. Do NOT visit your pit. Do NOT remove your bumpers. Do NOT remove your battery. Please DO bring your operator's station with you. At the Inspection station your robot will be reweighed. Since your bumpers were weighed at the Thursday inspection and we have a good idea how much a battery weighs, this check gives us a good insight if any uninspected modifications have been made. One of our more experienced inspectors (usually the LRI) will briefly look over your robot and may ask one or two random questions. In the event that the weight check and or visual indicates that uninspected modifications have been made, your team may be taken aside for a more detailed re-inspection, After passing re-inspection, you will get a colored sticker to place on your robot. Return to your pit and prepare for alliance selections. And Good Luck!

Some Inspection Items That Always Cause Heartburn <R16> Bumpers Batteries Pneumatics Safety Miscellany

Protrusions outside the Frame Perimeter (<R16>) Not OK OK OK Not OK

What FIRST Wants

C Channel Bracket Mounting A C channel mount requires additional fill to meet <R07> part M: The entire length of the BUMPER backing must be supported by the structure/frame of the ROBOT. i.e. the backing material must not be in “free space” between or beyond attachment points.

C Channel Close Up 1

C Channel Close Up 2 Note that this backing redefines the FRAME PERIMETER.

Angle Bracket Mounting The angle brackets allow easy disassembly and a flush mount to the frame.

What not to do… This example is not legal on at least two points. The “hard parts” of the bumpers overlap. The “soft parts” of the bumpers do not totally cover the corner.

What FIRST Wants Keep the “hard parts” out of the corners Cover the corner completely with “soft parts”

Is this gap allowed?

Is This Legal?

Good protection of the corner.

A pretty good idea…

Bumper Strength One way to determine how good your bumper connection needs to be is to do a little math. A robot being driven with CIM motors via an AndyMark Toughbox transmission (12.75 gear ratio) can achieve speeds of 11 ft/sec. This is the speed at which a robot could hit a wall or another robot (traveling at the same speed, bumper to bumper contact).

Bumper Strength The equation for the velocity, v, of a falling object after it has fallen a certain distance, h, under a uniform acceleration (gravity), g, is: v = sqrt (2gh) Solving for h we get h = (v**2) / 2g So, for v = 11 ft/sec we get h = 1.9 ft

Bumper Strength A drop from 1.9 feet is the abuse that your robot’s bumpers must absorb many times in each match! Consider also that, due to your robot being hit while an the bump, this force need not be orthogonal…

Battery Restraint Strength (Going Turtle)

Battery Restraint Strength (Going Turtle) Consider this free body diagram. The angular speed of a 44 inch uniform rod after falling 90 degrees at 1g is: radians per second

Battery Restraint Strength (Going Turtle) This means that the linear velocity at the end of the robot is 5.73 m/sec. The deceleration if effect on the battery will be dependant on robot design and battery placement. Somewhere between 30g and 130g (or more) Velcro will very likely fail.

Robot Signal Light (RSL) Solid ON = Autonomous Enabled Solid ON, but blinks OFF every 1.5s = Teleoperated Enabled Slow Blink (900ms on/ 900ms off) = System Disabled; caused by system watchdog, user watchdog or Driver's Station set to disabled Fast-Slow Blink (200ms on/900ms off) = Low Battery (<12V) or no user code AND system disabled either by system watchdog, user watchdog, or Driver;s station set to disabled Fast Blink (200ms on/200ms off) = System error: No driver's station communication, bad cRIO Image, bad team ID, extensive comm. error Jumper Pins 1 and 3

Think You Know Better? Early in January, you studied the game and decided on a strategy. Just as “form follows function”, you designed a robot to achieve that strategy. In most cases, you and your team have been reading, eating and breathing the 2010 Game Manual for over six weeks now. You have read every update to see how it affects your design. You have posted questions to the official Q&A forum and waited in anticipation of the response.

You DO know better! Some of our robot inspectors are FRC mentors and some are not. Regardless of their background, they have not studied those rules pertaining to your robot design as carefully as you have. It is very likely that you will know the rules better than the person inspecting your robot!

What to Do If You Disagree Show us the rule in the 2010 Game Manual. Show us the Update. Show us the Q&A post. Show us the FIRST web page or associated document. Show us the FRC Blog entry. Invoke <R94>

<R94> If a ROBOT is rejected by inspectors due to a safety issue or concern related to the team’s method of storing energy (see Rule <R01>), the concerned items must be disabled or removed from the ROBOT before it can compete in a MATCH. The team bears the burden of proof that such a rejection is not valid. Teams should be prepared to provide justifiable test data or calculations during inspection to support their design.

What NOT to do… Do not get angry with your inspectors if you do not agree with a rule. In many cases, we will dislike the rule just as much as you. Remember that you had the power to control your team’s destiny.