Minibot Falling Solutions

[GaryVoshol]

Originally Posted by jhellr13

Yes, but does the hostbot need to be completely off the pole tower before deploying the minibot?

<G43> allows the HOSTBOT to grab the TOWER during DEPLOYMENT.

[GaryVoshol]

Originally Posted by EricH

I had an idea: If the robot's arm just so happened to be up at the end of the match, just so happened to be about 10' tall, and just so happened to have a device at a shoulder joint that would allow any claws to be operated by hand without robot power being turned on, I don't think the refs can use the "special equipment" rule to disallow that being used to bring the Minibot down. It's part of the Robot, after all...

Does this apply?

<G22> HOSTBOTS may not contact their ALLIANCE‟S MINIBOT once any part of it has climbed above the DEPLOYMENT LINE. Violation: TOWER is disabled

Doesn't say how long the restriction lasts after the MINIBOT has crossed the DEPLOYMENT LINE.

[nighterfighter]

Originally Posted by GaryVoshol

Does this apply?

Doesn't say how long the restriction lasts after the MINIBOT has crossed the DEPLOYMENT LINE.

Considering the penalty is just a disabled tower, and the fact that the towers are disabled after the match...

Regardless, if the GDC were to outlaw the HOSTBOT from having an attached extension to retrieve the minibot, it would seem rather silly.

[jhellr13]

Originally Posted by GaryVoshol

<G43> allows the HOSTBOT to grab the TOWER during DEPLOYMENT.

Thanks for the reply. Idk if you read the previous posts, but our team is using a deployment system containing drawer glides and a scissor to guide the minibot to the pole/tower. Someone before said that putting memory foam on the hostbot is not prohibited. If my team were to put memory foam on the end of the deployment system such that when the minibot falls(let's hope not), it will hit the memory foam, would this be allowed?

[GaryVoshol]

If the MINIBOT is allowed to contact the HOSTBOT again after the TOWER is TRIGGERED, then using the memory foam as a soft landing pad would be a valid idea. But I don't know how <G22> is going to be interpreted.

[Hawiian Cadder]

lucky for us we have ryan, who is that tall.

[BJC]

You could always build a bunch of mini-bots then let the field crew rip it down every match. (The sad part is I'm only half joking ) Has the actual way they plan on getting a stuck mini-bot down been revealed? I'm guessing miniture chainsaw mounted on pole.

[Kevin Sevcik]

Originally Posted by Hawiian Cadder

lucky for us we have ryan, who is that tall.

Have you empirically tested this yet? I'm roughly estimating you'd need someone atleast 6'6" to make that reach. And that's assuming your minibot hangs down 12" from the target. You'd need someone about 7'2" to reach up to 122". This is assuming my rough body proportions math scales properly, and no jumping, of course.

[jhellr13]

Originally Posted by GaryVoshol

If the MINIBOT is allowed to contact the HOSTBOT again after the TOWER is TRIGGERED, then using the memory foam as a soft landing pad would be a valid idea. But I don't know how <G22> is going to be interpreted.

Yeah, that rule is so hard to interpret. Hopefully it will be interpreted into greater depth in a future team update.

[Doug G]

Originally Posted by jhellr13

Yeah, that rule is so hard to interpret. Hopefully it will be interpreted into greater depth in a future team update.

By shunting your motors when they get to the top, it will allow them to return back down at a slow and constant velocity. Ever drop magnets down a copper pipe? The same principle works for the motors. If the motor wires are shunted together, back emf will in effect prevent the motors from backdriving to fast. The trick we're still figuring out is how to switch the battery power off FIRST then shunt the motors SECOND. It's all about careful alignment of switches. Of course there's always the fuse that blows if it happens in the reverse order.

[jhellr13]

Originally Posted by Doug G

By shunting your motors when they get to the top, it will allow them to return back down at a slow and constant velocity. Ever drop magnets down a copper pipe? The same principle works for the motors. If the motor wires are shunted together, back emf will in effect prevent the motors from backdriving to fast. The trick we're still figuring out is how to switch the battery power off FIRST then shunt the motors SECOND. It's all about careful alignment of switches. Of course there's always the fuse that blows if it happens in the reverse order.

Yeah your thoughts are true. Today was our first time running the minibot on the pole. We are still developing it though. We also were running it on the standard robot battery, rather than the small battery meant to be used on the minibot. We still have to cut some weight and program the minibot, so things might change.

[Christian Z]

well if you our using an NXT brick and a motor control you could simply change the speed of your robot to a low power so the minibot will stop where you want it to.

[jhellr13]

Originally Posted by Christian Z

well if you our using an NXT brick and a motor control you could simply change the speed of your robot to a low power so the minibot will stop where you want it to.

Our team has decided not to use the NXT brick partly because it is added weight and because it isn't really needed. Our plan is to use a switch to activate the minibot when it hits the pole, and a switch to turn it off at the top, in hopes that it will slide down at a nice pace due to friction.

[Grim Tuesday]

What do people think about backdriving the motors down the pole?

[cmass]

Originally Posted by Grim Tuesday

What do people think about backdriving the motors down the pole?

We tried to reverse power ... doesn't work for our design.

What does work for us, assuming the bot stays up .... is to shake the pole just a little and the thing comes down either backdriving or falling.

Either way, its a good thing if we can catch it.