[ToddF]

I find this thread fascinating because it so beautifully illustrates the difference between the theoretically perfect world of academia and the real world in which engineers must design products to survive. I see so much angst being expressed by those who want to design for conditions they WANT instead of designing for the conditions that ARE.

The engineering challenge of designing and building a drivers station to survive harsh conditions is not particularly difficult. Boats, cars, airplanes, spacecraft, cell phones, digital cameras, and FRC robots are all examples of complex systems which must survive harsh shock and vibration environments to be successful. Elementary school students participate in competitions where raw eggs are dropped hundreds of feet and don't break.

The problem here isn't designing and building a robust driver's station. This is known technology. It's almost trivially easy. The problem is getting people to accept the fact that it's necessary. You can argue until you are blue in the face that robots shouldn't hit the wall hard. They do. You can argue that you've been in FRC for twenty years, and it's never been a problem before. Well, thank you for your years of service. That was then. This is now. You can lobby that the rules should be changed so robots that hit the wall are disqualified and matches are replayed. That will be small comfort to you as you contemplate the remains of your smashed drivers station.

It mystifies me how people can OBSERVE how harsh the conditions are, but still refuse to accept that it is necessary to build a robust driver station. It doesn't matter that you don't want it to be that way. It doesn't matter if the robots that hit the wall do so accidentally or on purpose. It doesn't matter if it's legal or not. At some point in this game, you are going to have a robot slam into the wall in front of you. It's up to your team to decide if you want to be a team who picks their driver's station up off the floor and continues with the match, or are you going to be the team that comes on CD and posts about how their broken driver's station cost them their match.

In one of our practice matches we went over the rock wall and our robot died. It turns out the battery strap broke, the battery jiggled around, and the connector came unplugged. I asked if the connector was zip tied and got blank looks. After fixing the strap, the students asked if they really needed to zip tie the battery connector, as it would slow down battery swaps. I told them that we wanted that connector so secure that if the battery came completely loose and was dragging on the ground behind the robot, it couldn't possibly come unplugged. We never lost power again in a match.

We use PS4 controllers for our driver and operator. Before the season started, we recognized there was a risk the USB cable could come unplugged from the controller and discussed possible mitigations. The students shrugged this off and never did anything about it. Predictably, in one of our early matches a robot banged the wall in auto, the controller fell off the shelf and came unplugged. The operator immediately plugged it back in, but the match was halfway over before it reconnected and he regained control. This would have been a disaster if we had not included buttons on the driver controller to lower and raise our ball intake, for just such an eventuality. Back in the pit, we used electrical tape to secure the cable to the controller. To test the security of the connection, we hold the controller overhead and drop it. It stops just short of hitting the floor by jerking on the USB cable. Repeat 3 times. If the connector disconnects, it's not good enough and the tape needs redone. We have had no problems with disconnected controllers since.

So, is it possible that you could design your drivers station so you could go on the roof of your school, toss it over the side, and have it survive? I say yes. Would this drivers station survive getting knocked off the shelf when a robot hit the wall hard? You bet it would. The ENGINEERING problem is a solvable one. So, accept that the operating conditions are harsher than you would like them to be. Define an operating environment that bounds the worst case, apply a safety factor, and design to that. Hope for the best, but DESIGN for the worst.