Another link clarification...

Just another boring link question...

Just to get confirmation on how a link is to be mounted on an overhead horizontal bar spinner: the bar has a larger diameter than any extent of the robot's main body, so there is no way to remove a link by hand while staying entirely clear of the weapon. Think Hazard from Battlebots.

To mitigate this risk - the weapon motors are brushless, which ensures that a possible motor controller failure will fail safe. A contactor will be installed on the power supply to the weapon ESCs, which is enabled and disabled by radio, and equipped with two WEAPON LIVE LEDs with independent paths of connection - this can also be tested by blipping the weapon throttle. Finally, the weapon and drive links (independent battery packs will be used for weapon and drive) will be located on the rear of the robot in such a way that they can be removed using a long handled implement from a safe distance (boat-hook or similar into an eye on the link).

My question is this: would the above configuration satisfy the removable link location demands (given that there is no way that a location on the robot's periphery can be anything like clear of the weapon - similar to a full body spinner), or is the link required to be installed centrally, accessible through a rod inserted into a hollow weapon shaft? I just want to clarify the answer so, if required, I can redesign the weapon drive structure and bearings (the bar too, as a much larger diameter shaft would be necessary).

Not a boring question at all but you will need to re-think your design as Hazard would fail on the FRA Build Rules. You will need to refer to Paragraph 6.3 concerning removable links - specifically 6.3.2:
http://www.fightingrobots.co.uk/docu...es_2008_v2.pdf

One suggestion is to extend the length of the body at the back to give clearance still leaves 3 sides with the bar overhanging - its late and I cant think of anything better at the moment :wink:

No can do, weight issues and it's a hell of a big bar :twisted:

Looks like it's hollow shaft time, shouldn't be too much of a deal to build in - just a couple of alterations to the weapon mounting which still only exists on CAD.

Then again, I might just try and run the design past the organisers and if so go with the original plan... I can name at least one robot with a much dodgier link placement than mine would be!

One other possible solution could be to have what Mini-Maul Evo (I think it was that one anyway) had a few years ago. It had a spinning bar quite large in diameter too (~70cm I believe) but to deal with the link problem, the robot had a small pod that extended about 30cm out the back of the robot and cleared the reach of the bar to house the link and the LED. It would be extra weight but wouldn't be as much as what would be gained by extending the full back end of the robot.

Yes it could mean that machines might try and attack that small pod in order to immobilise you, but if you make it strong and compact, and have a suitably placed spinning bar as a deterrent ( :)) it should be fine as a solution

Or you could go for a hollow shaft design :P

Quote:

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Originally Posted by k_c_r

One other possible solution could be to have what Mini-Maul Evo (I think it was that one anyway) had a few years ago. It had a spinning bar quite large in diameter too (~70cm I believe) but to deal with the link problem, the robot had a small pod that extended about 30cm out the back of the robot and cleared the reach of the bar to house the link and the LED. It would be extra weight but wouldn't be as much as what would be gained by extending the full back end of the robot.

Yes it could mean that machines might try and attack that small pod in order to immobilise you, but if you make it strong and compact, and have a suitably placed spinning bar as a deterrent ( :)) it should be fine as a solution

Or you could go for a hollow shaft design :P

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I've considered that. I've also pretty much come to the conclusion that it'll get horribly smashed and my weapon will stop working, plus the need for lots of wasteful additional high current wire run. Hollow shaft will be the way to go I believe.

One last bit of confirmation with regards to the 1.2 exemption (contacting the organiser with regards to any machine which doesn't fit within the rules): my understanding is that there is at least one full body spinner (Dizzy Tilly) that runs with a link under the robot and therefore in violation of rule 6.3.2 - in addition, every large flipper would as I understand it fail when in an inverted state due to the whole jumping 10 feet in the air issue. I might have to ask James about that, as he runs the only(?) full combat arena...

Personally the best example i've seen is the new little spinner (FBS version) with a link inside the shaft at the centre of the robot as you have suggested in the first post. But if all the rules regarding locking pins are also followed then even if the link is not done by this method it can still pass tech check. The robot will be armed and disarmed with the bar locked to the chassis by whatever method you choose usually a bar through the chassis. So when the link goes in it should be 'safe', all robots shoud be treated as dangerous whatever state they are in. If the robot goes out of control being a spinner then it will not be approached by an arena marshal until the batteries have run out, so it doesn't matter where the link is.

OI! we started that Mr Wallace! :P

Ed
You should have a PM please call me about a job for Seraphim asap

Thanks

Craig

Hi Nick,
I'm the tech checker and Arena marshal for all the Robo Challenge events (i'm James' brother btw!).
Ideally the best solution would be to have a hollow shaft with the link in the centre, but it can be abit of a pain if they get flipped upside down aswell!
Dizzy tilly's link isnt in a particularly good position but there are ways of removing the links safely depending on the robots design.

Where ever the link on a robot is, or what the robot is, we always try to put in the locking pins in the weapon before I begin disarming them. This minimises any risks as soon as possible (unless for somereason theres more hassle putting the locking pin in :angry: ).
Once the locking pin is in, it is usually safe enough, especially with non-pneumatic robots to turn the robot over, or access the robot where it would normally be a risk.

Obviously, this isnt the prefered route but if no other method is do-able, then the above method can be acceptable aslong as i deem it safe enough during a tech check.

Main things I would check is that you locking pin needs to be able to easily secure the weapon under its full load at all times, and mainly that it is eay to put in and wont fall out easily. Then put your link where you think will be easiest to access it from there.

From your first post and precautions you have take, i believe your sensible enough to come up with a solution you believe is safe from what i have written above. If you have any queries let me know and i'll happily tell you if i'll put my fingers near it or not :lol:

Oh - the other thing, using something to hook the link and pull it out sounds a good idea, although the force required to remove most links would just pull the robot along with the link :rofl:

Quote:

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Originally Posted by grant_ploughbot

Hi Nick,
I'm the tech checker and Arena marshal for all the Robo Challenge events (i'm James' brother btw!).
Ideally the best solution would be to have a hollow shaft with the link in the centre, but it can be abit of a pain if they get flipped upside down aswell!
Dizzy tilly's link isnt in a particularly good position but there are ways of removing the links safely depending on the robots design.

Where ever the link on a robot is, or what the robot is, we always try to put in the locking pins in the weapon before I begin disarming them. This minimises any risks as soon as possible (unless for somereason theres more hassle putting the locking pin in :angry: ).
Once the locking pin is in, it is usually safe enough, especially with non-pneumatic robots to turn the robot over, or access the robot where it would normally be a risk.

Obviously, this isnt the prefered route but if no other method is do-able, then the above method can be acceptable aslong as i deem it safe enough during a tech check.

Main things I would check is that you locking pin needs to be able to easily secure the weapon under its full load at all times, and mainly that it is eay to put in and wont fall out easily. Then put your link where you think will be easiest to access it from there.

From your first post and precautions you have take, i believe your sensible enough to come up with a solution you believe is safe from what i have written above. If you have any queries let me know and i'll happily tell you if i'll put my fingers near it or not :lol:

Oh - the other thing, using something to hook the link and pull it out sounds a good idea, although the force required to remove most links would just pull the robot along with the link :rofl:

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The locking pin is a simple U shaped staple which fits over the blade and down through two holes through the chassis, so that's pretty easy to install and I'm sure will take the torque of the motors. I believe using a decent locking mechanism and an electrical interlock on the weapon will sort out any hazards when powering up - the drive system link goes in first, then the weapon link, then the weapon enabling switch (controlling the contactor which supplies the weapon motor escs) can be switched on and off to make sure the weapon live lights work and then go out when switched off - then the pin can come out and it should be ready to go.

As for pulling the link out from a distance, can I suggest just using one of those snooker cue rests? Should hold the robot at a distance while taking the link out with the hook...

Saves me all the gearbox redesign issues anyway :evil:

That sounds resonable to me....
It will probably be easier for us to remove the link by hand, so aslong as the locking pin is easy to slide in then i'm sure it will be ok with all the precautions you have taken.

doesn't that class as a tool

which in the rules states you can't use tools to remove the link ????

Thats partly why removing it by hand would be better anyway.

Can someone call Ed Wallace and tell him to call me please 0790 330 5564