Re: Al's Annual Inspect before you ship! thread.
 

Next,
Have I talked about bumpers yet? Bumpers are and will continue to be a place that teams seem to miss the mark. The rule for bumpers is a long one with several paragraphs. The rule R07 is to be taken in it's entirety when designing your bumper system. What may not be immediately evident is the "hard parts" shown in Figure 8-1 is a cross sectional view. The "hard parts" refers to the items used in the construction of the bumper, not the robot frame. These parts include the hard 3/4" plywood backing, the hard aluminum angle and the hard fastening system. Your bumper system must also conform to all of the rest of the figures as well. No plywood shall extend beyond the corner of the frame as shown in Fig 8-4. No bumper shall cross an opening in the frame structure as shown in figure 8-3 and par M. Any segments in bumper design must be a minimum of 6" long as shown in Fig 8-2 and par B.
As has been discussed earlier in this thread, bolt heads, rivets and other fasteners can extend outside the FRAME PERIMETER in the BUMPER ZONE only. To allow for a secure mounting of the bumpers to the frame, small clearance holes can be made in the back of the bumper.
Please consider how you will lift the robot to place it on the field and remove it. Bumpers are not the best alternative for this. Many teams devised lifting handles for their robots last year and those systems greatly impressed the UL safety advisors. Some were as simple as rope attached to the frame and threaded through a six inch length of 1/2" PVC tube. Some were more elaborate using aircraft cable or flip out handles.

Re: Al's Annual Inspect before you ship! thread.
 

Gary,
According to the manufacturer, the crimped power lock or Anderson connectors are in the order of .01 to .5 milliohms. We improve that a bit by soldering the crimp so I am confidant the connection is well below the .5 milliohm max. The #14 wire is something like 2.5 milliohms/ft. The reason we use power locks is to make repairs easy and fast. When practical I would recommend a direct connection to the controller.

Re: Al's Annual Inspect before you ship! thread.
 

Thanks Al for the reminder. You are myHero!!

Re: Al's Annual Inspect before you ship! thread.
 

I have just helped a couple of rookie teams with the protruding bolts problem, so here are a couple of thoughts. (Full disclosure: When we did the CAD and weld for the frame, our team captain hadn't completely digested the rules and didn't notice the difference between bolts protruding inside and outside the bumper zone. So we had to follow some of this advice ourselves. Fortunately he followed our 36 x 26 unless it absolutely has to be bigger rule, so we had space to add on to the frame to extend the bumper perimeter.)

First a thought that occurred to me this morning. Our welds would probably make our robot illegal if we hadn't already had to make corrections for the bolt heads. The welds stick out a little bit from the flat surface of the structural tubes. I would not be surprised to see some other teams with this problem with welds as well.

If you have protruding bolts and you are pushing the edge of the 38 x 28 max dimensions, you need to spend some serious time thinking about your design right now. This is true of a lot of teams that used the C-Base for a robot without a lot of ground clearance.

If you have some space and weight to spare, you can put a rail around the edge of the robot in the bumper using aluminum u-channel. You can use something like this: http://www.mcmaster.com/#4592t16/=5xioph
If you put this around your frame but inside the bumper zone, you can add a bolts head width to your frame inside the bumper zone, which makes that the new frame perimeter. This is only going to work if there is something solid to attach it to, but since you have to have a solid place to attach the bumpers you should be OK. Basically think of this as wrapping your robot in a 1" x .5" or 1" by .25" strap inside the bumper zone. The outside edge of the strap will then be the FRAME PERIMETER.

Don't try to bore a big hole in the side of 1x1 aluminum tubing or c-channel stuff and countersink bolt heads. This greatly weakens the structure of the frame.

Al, thanks very much for the thread. Even after 9 years of doing this I learn things. Never thought about cutting back the leads on the CIMs to increase the length of 10 AWG run while decreasing the length of 14 AWG.

Re: Al's Annual Inspect before you ship! thread.
 

We used a strip of 1/4" plywood on the outside of our 1"x1" box tube to accomplish the same thing. We roughed up the aluminum with a file and attached the strips with hot glue. The strips are very light and should be plenty strong as they just transfer the load to the aluminum. The hot glue should also be plenty strong as the strips are always being pushed against the frame and never pulled off of it.

Re: Al's Annual Inspect before you ship! thread.
 

Kevin,
I would like you to rethink the hot glue idea. When you glue to aluminum tubing without it already being hot, it is like a cold solder joint. I am hoping you are not depending on this to be a structural joint.

Re: Al's Annual Inspect before you ship! thread.
 

Al,

As I mentioned the joint is always in compression when the bumpers are installed. There is no way to put the joint under tension or shear. The pieces are simply shims to fix our frame perimeter error.

The hot glue joint is pretty much there to keep the pieces on the frame when the bumpers are off. The largest shear force is gravity.

Re: Al's Annual Inspect before you ship! thread.
 

Good answer.

Re: Al's Annual Inspect before you ship! thread.
 

So your frame will never flex or bend when you're driving, turning, bumping, hoisting? Hmmmmmmm.........

Re: Al's Annual Inspect before you ship! thread.
 

OK,
Time for a little departure to Al's personal list of what I like to see when I walk up to inspect your robot in your pit.
1. Nice safe work area, not too many power cords laying around, or low hanging objects and everyone wearing safety glasses over their eyes.
2. Battery terminals nicely insulated on all batteries. Gold star if you have changed the alligator clips on your charger to an SB50 battery connector as recommended.
3. No shop compressors, they are loud and draw enough current to trip breakers for other pits. No grinders, torches, or welders. A gold star for a safety checklist or some form of safety awareness.
4. Students and lots of them. All smiling and happy in their work.
5. A good worksurface or elevated cart for the team to work on the robot.
6. No auto type battery chargers capable of more than 6 amps ever.
7. A robot with no obvious sharp edges, no entanglement issues, and no mechanisms that will jump out and whack me or some else when I least expect it.
8. Covers off or open, bumpers ready to go on, a battery ready to be installed and the driver station ready to be tethered.
9. I will ask for a lead electrical student, a lead mechanical student and a pneumatics students if your team has one. Everyone else can take a giant step to the outside of the pit.
10. If a judge is present and asking questions I will return when they have finished.

Re: Al's Annual Inspect before you ship! thread.
 

Great point. I can't tell you how many times I went to the pits last year, and a mentor was trying to answer the questions. I know that we all get excited about our work, but this is the time for the kids to shine. Let them be responsible for their work. Mentors should be training the 'leads' on how to answer the inspection questions.

Re: Al's Annual Inspect before you ship! thread.
 

Good point. If the hot glue pops off due to that we will redo it or use another adhesive to attach the strips.

We also probably have room to bolt through the strips if it becomes necessary and pocket the bumpers, but we would like to avoid that.

Re: Al's Annual Inspect before you ship! thread.
 

Next installment, looking at the Inspection Checklist.
Rev A is on the First website now and another revision is currently in process. Start working through the list with your students. This will allow you and them to fully understand everything that is there and will give you a logical path to check.
The first section has weight and size checks for both the robot and both sets of bumpers if you have chosen this option. This occurs at the inspection station where the scale and sizing box are located. Bring your robot and bumpers and the thumb drive with your BOM file on it. The BOM will be copied to the computer in the inspection station. Please follow the naming convention provided.
During sizing, your robot will be inspected for FRAME PERIMETER and incursions.
Depending on the regional, the remainder of the inspection will take place in your pit. Inspectors should ask for a lead electrical student and a lead mechanical student to walk them through the inspection process.
The next section is the mechanical inspection. We will check for items on the robot that can damage people, damage the field or damage other robots. This is a hands on part of the inspection where the inspector will run their hands all over your robot checking for sharp edges, protrusions, parts that can puncture balls or hurt your students when they are lifting the robot. Fear not, this laying of hands imparts good luck. You will be asked to call up your BOM on the Classmate while the inspection continues so that the inspector can look for items in the BOM.
Of interest will be the ability for your robot to kick, what method or stored energy you are using and how safe the mechanism is during transport. It is of prime importance that stored energy of any legal form cannot be released accidentally while in the pit, while being inspected or while transporting the robot to the field. Please make sure the students that are involved in the inspection have full knowledge of how the locking device functions and how effective it is. During this part of the inspection, we will look for decorations and signage. Your robot should have your school and sponsor names on the robot and any logos. Be proud of your school and sponsor and show off.
Lighted decorations will also be checked for hazards to people and damage to the field.
Finally, your ability to have balls enter the FRAME PERIMETER by no more than 3" will be checked as well as your kicker extending beyond the FRAME PERIMETER but not beyond the BUMPER PERIMETER.
Stay tuned for the electrical inspection in part two...

Re: Al's Annual Inspect before you ship! thread.
 

Part 2, Electrical Inspection
Inspectors will ask to see your battery inventory to check for insulation, battery type and safe handling.
This year's game is going to involve a lot of violent activity so the battery must have a secure mounting system. A cage or box that hold the battery in place is a good start. Tywraps, velcro belts and pipe strap are not going to suffice this year without something else to hold the battery in your robot. If it falls out, you will be disabled.
We will look for your main breaker, it needs to be easily seen with covers in place and accessible to anyone on the field. If your robot starts to smoke, you want someone who can turn it off so you can play again later.
Since the Linksys wireless is out of production, you can have either the WET610Nor WGA600N and they must be powered from the dedicated +12 volt connector on the PD.
Inspectors will compare the breaker size installed in your PD with the wire size that is leaving the PD. 40 amp gets a #12 or larger, 30 amp gets a #14 or larger and 20 amp gets a #18 or larger. During this check, color coding will also be checked. Remember, only one wire per Wago connector.
Moving on to servos, they must be connected to the digital sidecar and will be checked for type. Be prepared if you are using a larger type that you can support the torque specs.
Next will be a motor check and count. No more than 5 CIM, 2 Denso Left, 2 Denso Right, 2 Fisher Price, and 2 Mabuchi. That means no Globe, no drill motors, no early FP motors and no van door motors. No modifications except for output shaft and mounting holes. No drilling of the case, sanding, machining, or dis-assembly. Only one motor per controller and CIM and FP motors must be controlled by a speed controller.
For some of the teams, there will be custom circuits to check over and powered decorations. Please remember that all need to be fed from a circuit breaker.
Connections to the frame of the robot are not allowed so you will need to show insulation for both the Crio and camera if you use it as well as any custom circuits or sensors. Ohmmeter checks may be needed to verify this part of the inspection.
Finally, the firmware updates will be looked at. If you use CAN, the Jaguars will need the latest version of firmware in order to work with field control and for safety.
Part 3 will cover pneumatic checks and power ON tests.

Re: Al's Annual Inspect before you ship! thread.
 

Part 3, Pneumatics and Power ON Tests.
If you do not use pneumatics your inspector will just skip this part but it appears that more teams will use pneumatics this year than ever before.
The First thing an inspector will look at is the compressor. If you are using one of the equivalent devices allowed this year, be sure to have the spec sheet to show during inspections. Your inspector will also make sure you have entered it on the BOM. The pressure relief valve needs to be mounted on the compressor and calibrated per TU#11. If you are using an off-board compressor then several robot rules apply including R79 for an additional pressure relief valve. Please point out the Spike used to control the compressor.
If an off-board compressor is used for 120 psi, then only the compressor can be off board. Everything else must remain on the robot including the Spike, pressure switch, etc. When using only 60 psi stored pressure, the regulator can also be placed off-board.
The inspector will continue to look for required pneumatic system parts, the pressure switch, regulator, two gauges, one for high side storage and one for working pressures, no more than four accumulators, etc. Inspection will continue to look for extraneous tubing, odd valves and actuators over 2" bore and 24" stroke. Most importantly, inspectors will be checking for safe methods of mounting and securing moving parts, especially those parts used for working pressure storage only.
Moving on to the Power ON testing, you will be asked to insert a battery, tether your robot to the operator's control system and turn on power to your robot. During this procedure, we will be checking to see if the robot signal light is flashing and the team number is correctly displayed. You will then be asked to enable the robot while we check to see if the RSL stops flashing, the compressor (if you have one) starts to run and pressure builds up to 120 psi and then shuts off. You will need to demonstrate that the battery voltage is correctly displayed on screen, and show the firmware for the Crio and DS are the correct version number. When complete, you will be asked to turn power off, vent any pressure while we check for complete system vent, and all LEDs are extinguished.
Once everything is passed, your captain and team mentor will be asked to sign the the inspection form and a passed sticker will be added to your robot.
Please remember that all events require you to have re-inspections following any changes to the robot. I would suggest that you contact your LRI prior to any changes for assistance in making the changes legal. Also, robots that will be playing in finals matches and alternate robots will be required to be reinspected prior to finals match play. Check with your LRI for the procedure for this inspection. Most events will be using a modified inspection process for the finals. Leave your bumpers on and come weigh in. If your combined weight matches your inspection weight for robot and bumpers, then you will pass the second inspection. If your weight is different, be prepared to explain the difference (even if the weight is lower) and expect additional inspection. As always, random re-inspection can take place at any time during the weekend at the discretion of the LRI, FTA or Head Ref.
Have fun everyone and Good Luck!