Safety Issue: Robots Moving in Pits

[Sperkowsky]

Originally Posted by JamesCH95

Consider making a robot 'playpen' instead. A plywood sheet covered in carpet with a rigid barrier around the edge. Robot drives on carpet, works with any chassis, robot can't drive away, no blocks to tip over...

Not a bad idea.

[robochick1319]

Originally Posted by JamesCH95

Consider making a robot 'playpen' instead. A plywood sheet covered in carpet with a rigid barrier around the edge. Robot drives on carpet, works with any chassis, robot can't drive away, no blocks to tip over...

How would this fit in the pit? Would it just be the same size as the robot? Would it be in the pit all the time? I ask because I can't visualize a 10x10 space fitting toolboxes, fenced off playpen, and crew members coming in and out on a regular basis.

I think I should also clarify that when I have mentioned "blocks", I was implying blocks that were securely fastened to a cart or a table or whatever the team uses to work on the robot. Obviously just laying blocks on the ground with a robot on top doesn't prevent someone from bumping the robot and then causing the blocks to fall.

[JamesCH95]

Originally Posted by robochick1319

How would this fit in the pit? Would it just be the same size as the robot? Would it be in the pit all the time? I ask because I can't visualize a 10x10 space fitting toolboxes, fenced off playpen, and crew members coming in and out on a regular basis.

I think I should also clarify that when I have mentioned "blocks", I was implying blocks that were securely fastened to a cart or a table or whatever the team uses to work on the robot. Obviously just laying blocks on the ground with a robot on top doesn't prevent someone from bumping the robot and then causing the blocks to fall.

Precisely (part of) my point: any useful sort of device to stop a robot from driving off will occupy a lot of space that should be reserved for other usage. Theoretically it could be made with a very low barrier around it's edge, but it would still occupy a lot of space.

However, I still think any sort of dedicated platform is overkill if proper precautions are used. Even blocks bolted to a cart or table are fallible and could result in a robot getting tipped over. How do you ensure nothing is caught in the wheels? Or that the robot is sitting just right on the blocks so the wheels don't touch anything? How do you lock down the robot so it can't tip?

The reasonable answer always comes back to "a person has to check" and, in my mind, a person hovering over a disable button is just as good as a person spot-checking everything to do with blocking up a robot, or pulling breakers, or fiddling with code, or whatever the selected safety method is. The important thing is to be redundant in your safety measures and to have a practiced mode of operation so that everyone near the robot knows what could happen and how they must respond. The exact details are largely irrelevant.

[jman4747]

Originally Posted by JamesCH95

Consider making a robot 'playpen' instead. A plywood sheet covered in carpet with a rigid barrier around the edge. Robot drives on carpet, works with any chassis, robot can't drive away, no blocks to tip over...

I noticed last year a LOT of extra space at Peach Tree. Obviously you couldn't add a few more practice fields due to money, personnel, time, etc. (the room in the GWCC could probably hold another 4 or more) but you could add several ~10' square spaces with simple guards around them so people have an out of the way area to practice sub systems. Obviously this only works if the regional had that kind surplus area.

[techhelpbb]

Originally Posted by jman4747

I noticed last year a LOT of extra space at Peach Tree. Obviously you couldn't add a few more practice fields due to money, personnel, time, etc. (the room in the GWCC could probably hold another 4 or more) but you could add several ~10' square spaces with simple guards around them so people have an out of the way area to practice sub systems. Obviously this only works if the regional had that kind surplus area.

Same point I made before.
Most venues I have been to in MAR had some room they could find for this purpose.
All they need is floor really and perhaps scrap rug.

[Sperkowsky]

This is my solution. It took me about an hour. It's simple made out of 2x4 and plywood. Basically we will have this on hand at sbpli for testing and people can't put rest their chassis on the wood blocks while still being able to test mechanisms. This is obviously not perfect but it's something.

So yea if anyone here is at sbpli come to our pit and get this thing before you test.

[robochick1319]

Originally Posted by Sperkowsky

This is my solution. It took me about an hour. It's simple made out of 2x4 and plywood. Basically we will have this on hand at sbpli for testing and people can't put rest their chassis on the wood blocks while still being able to test mechanisms. This is obviously not perfect but it's something.

So yea if anyone here is at sbpli come to our pit and get this thing before you test.

Attachment 18661

Great job! Let us know how it works out!

[AdamHeard]

Originally Posted by Sperkowsky

This is my solution. It took me about an hour. It's simple made out of 2x4 and plywood. Basically we will have this on hand at sbpli for testing and people can't put rest their chassis on the wood blocks while still being able to test mechanisms. This is obviously not perfect but it's something.

So yea if anyone here is at sbpli come to our pit and get this thing before you test.

Attachment 18661

How does this solve the frame to wheel offset problem?

[Alan Anderson]

Originally Posted by Sperkowsky

This is my solution. It took me about an hour. It's simple made out of 2x4 and plywood...

Attachment 18661

I don't understand how this is supposed to help. If the chassis is intended to sit on the 2x4 frame, the bottom plane of the robot's wheels will be well below the raised platform on which the tote is sitting. Unless I'm missing something basic about how you are expecting this to work, you've taken the problem of the robot being higher than the floor and turned it the other direction. Am I simply failing to see what it's meant to do?

But even if I am missing something basic, robot frames are not all at the same height off the ground. I'm afraid that this "solution" would not work for a large fraction of the robots I have seen this year.

[robochick1319]

Originally Posted by Alan Anderson

I don't understand how this is supposed to help. If the chassis is intended to sit on the 2x4 frame, the bottom plane of the robot's wheels will be well below the raised platform on which the tote is sitting. Unless I'm missing something basic about how you are expecting this to work, you've taken the problem of the robot being higher than the floor and turned it the other direction. Am I simply failing to see what it's meant to do?

But even if I am missing something basic, robot frames are not all at the same height off the ground. I'm afraid that this "solution" would not work for a large fraction of the robots I have seen this year.

Perhaps not but if it works for his team and even one other that is progress, right?

[jman4747]

Originally Posted by robochick1319

Perhaps not but if it works for his team and even one other that is progress, right?

+1

Just make one for your own robot guys.

[Siri]

Originally Posted by robochick1319

Perhaps not but if it works for his team and even one other that is progress, right?

Only assuming that it doesn't not work for some other team so spectacularly that it actually adds to overall the safety risk. For instance, one of the hypothetical teams in this thread that makes mistakes pulling breakers or disabling code may position it improperly, or do a test that shifts robot CG such that it launches off the rig. Among other potential failure modes.

To be clear, this is at least slightly tongue-in-cheek. But there seems to be a lot of "my solution is foolproof, but here, let me build a better fool to break yours" going on. I have no reason to believe that this rig will actually harm anyone at SBPLI, and commend the effort towards what I hope and believe is a full spectrum attempt at safety culture. Kudos.

At the same time, I think we're all simply cautioning that, regardless of your solution, common sense/safety culture is still necessary to implement it properly. Raising the wheels is by no means an entirely safe solution. In fact, I can think of specific cases in which allowing the wheels to spin under power is more dangerous than actually controlling that power digitally or electrically. Again, it takes critical thinking. Anything anywhere in life that is sold as a perfect solution comes with the danger that users will stop thinking about its risks.

[Alan Anderson]

Originally Posted by Siri

Raising the wheels is by no means an entirely safe solution. In fact, I can think of specific cases in which allowing the wheels to spin under power is more dangerous than actually controlling that power digitally or electrically.

Indeed, for much of the development of the TechnoKats' mecanum software this year the wheels would have a fit if they were lifted from the ground. The robot would jerk back and forth as the wheels convulsed, and it could easily have rocked itself off a set of blocks. Using closed-loop speed control does not play well with unloaded motors.

[robochick1319]

Originally Posted by Alan Anderson

Indeed, for much of the development of the TechnoKats' mecanum software this year the wheels would have a fit if they were lifted from the ground. The robot would jerk back and forth as the wheels convulsed, and it could easily have rocked itself off a set of blocks. Using closed-loop speed control does not play well with unloaded motors.

Really? We've used mecanum (even this year) and never had this "jerking" issue that rocked solidly placed blocks.

I guess I'm picturing jacking the robot up like a car then testing the wheels. Is there really that much sideways movement when your run the wheels off the ground?

[Sperkowsky]

Originally Posted by Alan Anderson

I don't understand how this is supposed to help. If the chassis is intended to sit on the 2x4 frame, the bottom plane of the robot's wheels will be well below the raised platform on which the tote is sitting. Unless I'm missing something basic about how you are expecting this to work, you've taken the problem of the robot being higher than the floor and turned it the other direction. Am I simply failing to see what it's meant to do?

But even if I am missing something basic, robot frames are not all at the same height off the ground. I'm afraid that this "solution" would not work for a large fraction of the robots I have seen this year.

This is made to work with a kit chassis build. Because of the lip the elevator can only go so low. Again I reiterate if someone has a chassis that is not a kit of parts one I'm sure they are an experienced team who already has safety procedures in place. I could spend all day building different blocks for different robots but I had to make one that worked with our bot and go from there. It's a step in the right direction and I encourage others to develop the idea better (I'm an electrical guy not a builder).