Canburglar Safety

[Bennett548]

As noted by Frank in his recent blog entry canburglars have the potential to be dangerous. We need to make sure to reduce or eliminate the danger of these devices.

We insert a steel pin into the linkage that drives our burglars when the robot is on the cart, and the pins are tied to the cart so they can't be forgotten before a match. We also unplug the motors when we know we won't be using them for a while, in case somebody forgets to put in the pins.

What is your team doing to make your canburglars safer?

Has anyone had an inspector bring up a canburglar safety issue yet?

[JVN]

I'd like to address the elephant in the room...
Many teams are now competing quietly, in the background, to build the world's fastest canburglar.

We all know that the guy next of us is trying to go faster. So we go faster. We know that he knows that we know he's trying to go faster... so we go even faster. We know that he also knows this...

We all know the solution at a certain point comes down to energy. How much energy? More. More, and more, and more.

Are these high energy, super fast canburglars safe?
Depends who you ask. Safe is not quantifiable. Safe is not defined in the manual. Safe is relative.

However... safe is required for legality.

G1 ROBOTS whose operation or design is dangerous or unsafe are not permitted.
VIOLATION: If before the MATCH, the offending ROBOT will not be allowed to participate in the MATCH. If during the MATCH,
the offending ROBOT will be DISABLED.

The blue box clarifies:

Examples include, but are not limited to:
A. Uncontrolled motion that cannot be stopped by the DRIVE TEAM
B. ROBOTS arms “flailing” off the FIELD
C. ROBOTS dragging their battery
D. ROBOTS that consistently extend outside the FIELD

All Canburglars must be "safe" to be allowed to compete, however "safety" is only loosely defined.

Who will determine which canburglars are safe?
How will this standard of safety be fairly and equally applied across all canburglars?
Will the World Championship be determined by an inspector's subjective decision that 118's canburglar is safe, but 254's isn't?

-John

[Loose Screw]

Safety is a very important aspect to always keep in mind, and each game has an aspect that is "dangerous". In 2013 someone at MSC took a frisbee straight to the face from looking into his robot's shooter.

2013 and 2014's games seemed questionable to me in regards to safety. Shooting hard frisbees the entire length of the field? Robots high on a flimsy pyramid? Throwing a giant ball at average head height? Those all came to mind, and unfortunately some people were injured.

When it comes to canburglars, the goal is to slam a small hook into the opening (or reach around the back), and drive forwards as fast as you can.

As an inspector, I'll be looking for ways to safely secure and disarm your canburglar. You don't want them to accidentally fire right onto a team member.

Another thing that's been a staple for robot design is to make sure none of your appendages have a pointy or sharp element to them, usually less than 1 square inch in area.

Finally, I would reccomend designing a "fail point" in your arms so if they do interlock with another team, they can safely break rather than exploding pieces into the crowd or other robots. Having a controlled failure is always better than an uncontolled burst of parts.

A piece of advise I would give to drive teams setting up is that if you know your robot and an opposing robot are going for cans, and there's a chance that you'll interlock, try to go for a different set. The earlier video on CD was a glimpse of what's to come for future can battles.

[JVN]

Originally Posted by Loose Screw

Safety is a very important aspect to always keep in mind, and each game has an aspect that is "dangerous". In 2013 someone at MSC took a frisbee straight to the face from looking into his robot's shooter.

2013 and 2014's games seemed questionable to me in regards to safety. Shooting hard frisbees the entire length of the field? Robots high on a flimsy pyramid? Throwing a giant ball at average head height? Those all came to mind, and unfortunately some people were injured.

When it comes to canburglars, the goal is to slam a small hook into the opening (or reach around the back), and drive forwards as fast as you can.

As an inspector, I'll be looking for ways to safely secure and disarm your canburglar. You don't want them to accidentally fire right onto a team member.

Another thing that's been a staple for robot design is to make sure none of your appendages have a pointy or sharp element to them, usually less than 1 square inch in area.

Finally, I would reccomend designing a "fail point" in your arms so if they do interlock with another team, they can safely break rather than exploding pieces into the crowd or other robots. Having a controlled failure is always better than an uncontolled burst of parts.

A piece of advise I would give to drive teams setting up is that if you know your robot and an opposing robot are going for cans, and there's a chance that you'll interlock, try to go for a different set. The earlier video on CD was a glimpse of what's to come for future can battles.

Chris,
Thank you for proving my point.
Are you the person in charge of judging whether canburglars are legal in STL this year?

Are we using the "Loose Screw" standard of canburglar safety? Or is there a different standard?

[Loose Screw]

Originally Posted by JVN

Chris,
Thank you for proving my point.
Are you the person in charge of judging whether canburglars are legal in STL this year?

Not at all. This will be my first time inspecting actually. Your point stands strong; safety is relative. I think the head refs should take a good look at these mechanisms, but it ultimately relies on teams' judgement when designing. If you build a mechanism that moves at high speeds with sharp hooks without at least 2 safety latches, don't be mad when the inspectors fail you.

I like the single hook grabbers the best because they can be built with easy failure points. That and there's less to get tangled with compared to a bar-behind-RC grabber.

[AdamHeard]

I'd say that 99.9% of launchers last year were more dangerous in terms of serious injury than most can grabbers we will see at champs this year.

Originally Posted by Loose Screw

Not at all. This will be my first time inspecting actually. Your point stands strong; safety is relative. I think the head refs should take a good look at these mechanisms, but it ultimately relies on teams' judgement when designing. If you build a mechanism that moves at high speeds with sharp hooks without at least 2 safety latches, don't be mad when the inspectors fail you.

I like the single hook grabbers the best because they can be built with easy failure points. That and there's less to get tangled with compared to a bar-behind-RC grabber.

What if the system is powered by a motor? A disabled or unpowered robot wouldn't need safety latches in my opinion.

[Loose Screw]

Originally Posted by AdamHeard

What if the system is powered by a motor? A disabled or unpowered robot wouldn't need safety latches in my opinion.

That is true. However, if there's stored energy involved (surgical tubing, springs, ect), I would reccomend a safetly latch. That latch could be as simple as a zip-tie that you'll cut after you're on the field.

[orangelight]

On the software side of things, if we wanted the driver to control the canburglars we would have them press two buttons simultaneously to raise and lower them. This is so they can't accidentally bump the button and have them triggered. It's a bit safer than just one button, especially on the practice field when lots of people are around. Also before we enable we make sure we are in the right mode and people are clear of the mechanism.

[Basel A]

Originally Posted by AdamHeard

What if the system is powered by a motor? A disabled or unpowered robot wouldn't need safety latches in my opinion.

Drivetrains tend to use motors, but safe teams put their robot on blocks in the pits (or integrate such blocks in their cart). None of your programmers have ever accidentally started the robot in practise mode and run auton without intending to?

I've never inspected or reffed, so I don't feel comfortable categorically saying you should have a latch of some sort, but it's just seems like good safety sense to include one if your mechanism is using that much energy.

[AdamHeard]

Originally Posted by Basel A

Drivetrains tend to use motors, but safe teams put their robot on blocks in the pits (or integrate such blocks in their cart). None of your programmers have ever accidentally started the robot in practise mode and run auton without intending to?

I've never inspected or reffed, so I don't feel comfortable categorically saying you should have a latch of some sort, but it's just seems like good safety sense to include one if your mechanism is using that much energy.

Extending that argument, then all motored system should have safety latches and/or pins.

I don't think that's a good solution.

[Basel A]

Originally Posted by AdamHeard

Extending that argument, then all motored system should have safety latches and/or pins.

I don't think that's a good solution.

Obviously it's a matter of degrees. Most motored systems aren't moving that quickly, don't have that much kinetic energy. These canburglars honestly seems more dangerous to me than a robot driving full speed. Compare those to an actuating tote-grabbing mechanism. You don't think the average inspector can tell the difference?

Originally Posted by Chris is me

He said "disabled or unpowered" - so why would the robot be moving? This is a distinctly different situation than what you're describing, which is accidentally enabling in auton instead of teleop.

Show me a robot that has an ultrafast canburglar and is always disabled or unpowered when it isn't on the field.

[Chris is me]

Originally Posted by Basel A

Drivetrains tend to use motors, but safe teams put their robot on blocks in the pits (or integrate such blocks in their cart). None of your programmers have ever accidentally started the robot in practise mode and run auton without intending to?

He said "disabled or unpowered" - so why would the robot be moving? This is a distinctly different situation than what you're describing, which is accidentally enabling in auton instead of teleop.

[Bennett548]

I think the danger is different this year: tip speeds are going to be much faster in general, because can burglars are usually long. From the videos I have analyzed, several canburglars go faster than 18 m/s [~40 miles per hour].

Canburglars also tend to reach out much farther from the robot that launchers did.

Last year our ball shooter used 4x 180N [~40lbf] constant force springs, but our motor powered can burglar still concerns me more because it deploys a somewhat sharp metal hook at high speeds about 1.8m [~6 feet] from the robot.

[faust1706]

Originally Posted by Bennett548

Last year our ball shooter used 4x 180N [~40lbf] constant force springs, but our motor powered can burglar still concerns me more because it deploys a somewhat sharp metal hook at high speeds about 1.8m [~6 feet] from the robot.

Assuming you use one of those constant force springs: the torque would be 332.77 NM (that's metre), or for Americans: 1.2652092 x 10^-13 ounce-lightyears (running joke at my university, "how many ounce lightyears is that?)

[asid61]

I would argue last year's bots were far more dangerous, as they had to launch heavy balls. Our burgulars are motor-powered, so no energy is stored on the bot.
Finding the correct rule to limit this would be tricky.