Rule 4.4 Remote Kill (Advisory Only)

Hello

I was reading the rules and this rule hit me the rule states:
4.4 Advisory only
In addition all middleweight, Heavyweigh and Superheavyweight robots should incorporate a remote Kill on a seperate channel of the TX/RX which should bring the robots failsafe devices to the pre-set off or zero position via a switch on the TX. This is to allow for de-activation of the robots from outside a fully enclosed arena

I am only building a feather so it really does not apply to me but I would like to incorporate it if I have weight. But my problem is how do people do this? It it through very complicated electronics? as if so I will probably not be much good but all help would be greatly Appreciated.

Thank You

Regards
Ian

The wording of this rule is confusing to me as well, Ian. I would imagine that the intention is to have a relay or contactor which carries all the current for the robot, pneumatic valve and fuel valve where appropriate which is operated by a separate radio control channel. You would need a fairly hefty contactor to do this for modern heavyweights.

Its a good idea but I havent seen many people doing it. In fact due to the vague wording Im not sure whether my robot meets this requirement or not.

How about solenoids to pop out the removable link? How sensible would be a CO2 dump be in this circuit as well?

I know some people have implemented a remote CO2 dump which I think is a good idea. The only disadvantages I can see are that it would require me to recharge my gas reservoir after every fight, rather than every 2 fights and it would also take quite a while to vent my reservoir through the regulator, so would increase the time between fights. Safety comes above these concerns, of course.

The standard removable links as supplied by Technobots require a surprising amount of force to disconnect and you would need a big solenoid to pop them out. I would also be worried about such a device activating accidentally while my hand was in the robot removing the link - it could lead to a broken finger.

Very true Jim and also I know chaos 2 has one and if you flick the switch off and then back on the robot works again i dont think it would work with the idea of a solenoid removing the removable link.

Regards
Ian

Jim just to point out the rule is Advisory only but I still if I had weight would like to do it.

Julian i dont think thats the idea. Its ment to be that the removable link is still in but the robot wont work even if other transmittors are on the same frequency the robot is effectively dead.

Any Help anyone?

Regards
Ian

Remote kill is just an additional layer of safety. In Storm II the remote kill shuts down the FET drivers putting the robot in a safer state. It doesnt make the robot safe, just safer.

Im not sure anyone has ever interpreted remote kill as popping out the link ! The point is that you can shut down the robot from a distance, a large solenoid such as the ones that Albright sell would be sutiable for a heavy, and a large automotive relay would be sutiable for a feather.

Jim - you should never have a robot full of CO2 sitting in the pits, you should always vent your gas at the end of a fight. Id be worried if you were not venting your tanks at the end of fights !

Ed
http://www.teamstorm.comhttp://www.teamstorm.com

Oh dear, have I done something wrong?

Preston was the first time Id run a robot with bottled gas - I attempted to check in my fire extinguisher but was told it wasnt necessary. I fitted it to the robot before the first fight, then opened the valve once it was inside the arena with the doors closed. After the fight I closed the extinguisher valve and vented the low pressure side of the circuit, so the only pressure left was that present in the extinguisher.

I had been led to believe this was standard practice, if not then I am truly sorry and I may well stop using pneumatics. In my defence this was done under the full supervision of the pit crew at Preston.

Id assumed from reading up that the machine had to be fully emptied of gas after every fight. However with the cylinder valve closed and the pipework vented, it is after all now just a CO2 fire extinguisher. We all walk past those every day and it would be considered dangerous if they were removed.

If I do go for a very conventional flipper then I dont think that the need for a remote kill is quite so important than it is for other types. If memory serves me, Typhoon has a remote kill (or at very least a switch marked kill which we should hope means that)

M2 has always had remote kill and simply uses a pair of cheap (£15) 180A relays feeding the speedo channels. I would not be without it and has saved a potentially serious incident from happening in the early days of roboting. A remote kill that relies on the FETs only is an additional safety layer and is fine for most circumstances. I personally requested that a remote kill should be mandatory on heavies.

Jim, Apart from RWs M2 has always sat on the bench with a charged CO2 bottle. I do not as a rule dump all of the CO2 at the end of a fight, all that has been required is to isolate the CO2 bottle and vent the system. This is to avoid wasting gas (each refil costs the event money). It is best to recharge the bottle immediately after a fight whilst its cold (we do not have pumped filling rigs at the majority of events). Until events have a CO2 cage to store bottles in, the best place for them is in the bot rather than on benches etc. With the CO2 dump valve open (mandatory when on the bench) and safety links / chains restraining any pneumatic weapon then I would suspect a risk assessment would be satisfactory.

Paul

Julian we have a remote kill for the petrol engine in Typhoon 2. This was used twice in series 7 when we hit the arena sidewall. The only other kill switch is the failsafe which when Tx contact is lost the robot stops dead. I guess you could in a way call it a remote kill switch.

Weve recently had a similar discussion in the Netherlands. The problem is that FETs can stay in a conductive state if they let out the magic smoke, and relays may stick. Allbrights are the best option, but they are not cheap and carry some weight. This has put a lot of people off.
Im all for a remote relay option. I even suggested to put an infra-red sensor on it so you can shut it down from a distance if the receiver fails somehow. The problem is it will make the sport even more expencive and it reduces relyability a bit because it is yet another component that may fail.

Apologies Pneumatic people - my mistake.

Ill stick to talking about things I know about !

Ed
http://www.teamstorm.comhttp://www.teamstorm.com

Eds solution is quite a nice one- disabling the drivers is effectivelly having a fail-safe on a switch. Is this the sort of thing the rule is after, or is it more of a kill switch in the strongest sense of the word- i.e. removing power to the bot?

Paul Cooper said:
M2 has always had remote kill and simply uses a pair of cheap (£15) 180A relays feeding the speedo channels.

How do you turn these relays on or off paul. I know its via a switch on the TX but what does this switch activate?

All help would be greatly appreciated.

Regards
Ian

My IBC has an output for an external relayed channel on it, when I get chance to play with the finer points of the bot, Im intending to connect a DPDT relay across this and route the drive motor leads via the relay. My spinner is controlled by an Electronize, the power supply for which is fed through a separate relay channel. Well, it will be if I can ever get the damn electronize to stay in neutral.

Ian- you canget solid state switches for Rxs from loads of places (technobots is prob the best place). They are just a circuit which plugs into the RX and switched either on or off depending on how you move the stick. Simple.

Oh ok but that wont really work if you have your rx run from your main batteries will it?

Regards
Ian

Found something that might help people. I am currently trying to work it out for myself. Thanks Garath

The Link:
http://www.lancasterbombers.com/electronics.htmhttp://www.lancasterbombers.com/electronics.htm


Regards
Ian Mc Donald

With regard to turning the FET drivers off being insufficient, I would say it is sufficient as the rule says it should bring the robot to a failsafe position, which one would interpret as meaning it failsafes. Certianly all the PIC based speedos ive seen failsafe by turning the disable pin high on the drivers. Whilst i cant speak for Eds I would imagine it does the same thing. Further to that, with the arguement that MOSFETs have been known to remain conductive having smoked, its normally only one FET that smokes at a time, and assuming were refering to h-bridges, the current has to pass through 2 fets, so the remaining fet should work anyway and stop the current flow.

Conclusion? Turning off the fet drives is a good solution in that its only a couple of extra lines of code, so it weighs and costs nothing extra, unlike switched and relays. On the flip side, only programmer types are in a position to do this anyway, so for the rest of us its switches and relays :)

Eddy, I have seen a number of bots out of control due to a) speedo failing with a shorted FET driver (quite common on NCC70s) and b) due to a CPU crash - if you say watchdog in reply then think again! In both of these cases attempting to turn off the driver enable will have no effect. I still believe that a remote kill that switches off the FETs is fine in most cases but is not as good as a electro-mechanical power interrupt but far better than nothing. I will never run a heavy without a power relay circuit, if nothing else, it has saved the embarressment of a runaway bot following a Vantec crash.

Paul

Thank you Paul. That would suggest that the rule may need perhaps some re-wording, as it is not too difficult to take a seperate channel of the TX/RX which should bring the robots failsafe devices to the pre-set off or zero position via a switch on the TX. as meaning that making the controllers failsafe as they normally would is acceptable. As you have described above, that seems to frequently be insufficient. Perhaps in the next revision of the rules (whenever that may be- I seem to remeber Andy Kane mentioning that due to insurance they are either fixed now, or soon to be fixed, for a set period) a note be added on what is deemed acceptable- i.e. that relying on a uProcessor of FET driver is not really suffiecient, or at least not the prefered method? I have no problem with conforming to either of these, but will from now one favour the relay approach.

Thanks,

Eddy

Good to know Im in the clear about the CO2 tanks. No need to apologise, Ed - if you have concerns you have to raise them even if you dont know everything about the field in question (who does?)

Whatever remote kill system you put in place can of course fail but if you make your weapon or drive reliant on more than one system (speed controller plus relay for example) and you keep them as separate as possible you drastically reduce the risk of a runaway robot.

I will see if Maplin have any of the 180A relays tomorrow for my robots. I suspect that space rather than weight will be a problem for many existing robots though.

This is where my not-yet-roboteer paranoia comes in. Id been wondering about failsafes (for heavyweights). Although I wouldnt want the failsafe to fire when not needed, Id want the fail safe to be *really* safe.

The old Phoenix mainframe in Cambridge used to have a shutdown which fired a glass bolt through the power line (we hypothesised it was for use if it ever became self-aware). Id kind of been thinking along those lines for the robot - chomp a (replaceable) wire as it leaves a battery terminal with a spring-loaded nonconductive (ceramic?) blade of some kind, with a small solenoid holding it in place. Strikes me as a simple and pretty reliable system, and probably not too heavy.

I like the infra-red backup idea, by the way.

Would I be vastly over-engineering this?

--
Fluppet

Euhm...
YES! :)

Just so long as I know. :-)

--
Fluppet

Well Andrew basically all you need is just to be able to turn on and off the power to the drive and weapons. This can simply be done through some large relays (about 70amps per motor for feathers and 150amps per motor for heavys) These could be simply turned on and off by an electronic relay device such as the electrolise range from technobots.


On a different note would Ian Watts Failsafe double as a remote kill switch?

Regards
Ian

Okay; Im just particularly allergic to pain when it comes to being attacked by 100kg robots. :-)

If someones wandering around with random radio signals (as at the Robot Rumble 2003 when some kids were playing with an r/c car outside) or if theres a chance my electronics might go haywire - always a possibility, if someones stuck an axe through them, or if theyre designed by someone as incompetent as me - I like the idea of being able to kill the thing. Being able to do it in such a manner that it cant get switched back on again would be favourite.

Of course it does mean Ill have to make damn sure that nothing activates it when I dont want it to, but thats a small price to pay. Im made nervous enough by the idea of sticking my arm through some railings to stick the link in - trapped limbs and snapping noises haunt my thoughts, and in the past Ive proposed the idea of a cattle crush to hold robots still before entering the arena. Trying to turn off a robot which is going King B or doing a Behemoth (vs Mute) isnt my idea of fun, if the control system is already known to be flakey. I have an innate concern that relays might weld themselves in nutty robot mode, and for as long as I might consider things like flippers which automatically fire when somethings on them, I want to be sure my failsafe wont get stuck.

I trust (relatively) everyone else to be competent with their failsafes - but since Ill be the one with my hands on the removable link, I reserve the right to be very paranoid with my own! (Its just nice to know *how* paranoid!)

Anyhoo, back to people with less extreme solid-state systems (which Ill probably use as well - no need to spend more time than necessary replacing wires!)

--
Fluppet

Ian as Paul says it is quite possible for speedos to fail in a state where they just run even without a signal. In this case the failsafes will not stop a run away bot.

I actually had this happen on my weapons speed controller once, luckily it wasnt connected to my disk at the time. Thats why Im intending to use a mechanical relay this year.

Im using the Ian Watts interface as well this has two weapons channels & I intend to use one to control a mechanical contactor. Now of course someones going to argue that I shouldnt use the mixer to control the contactor in case my mixer fails :).

Richard Wenman
Team Mayhem

Its sounds to me Andrew that your a little too paranoid. If your that paranoid about getting hurt or something going wrong then robotic combat may not be the sport for you. Perhaps tidley winks is more suitable :)

But the most safety concious teams i.e. Big Brother, Tornado, Shredder and Dantomkia all have something simular to relays fitted. Now by saying there the most safety concious I am not taking away from anyone else I am sure that most if not all teams are very very very safety concious but those 4 sprang to mind.

As for relays welding themselves shut jsut make sure the current your robot can draw is much lower than the relays mak current i.e. if the robot can draw 10 amps use a 15-20amp relay. Equally if the robot can draw 200amps use a 300-400amp relay. Thats my opinion but as I said its up to you.

Regards
Ian

:-) Thank you, Ian, but Im only the world number 24 at tiddlywinks - Id like to do better with a combat robot (I know, thats fighting talk!) Besides, winks isnt a spectator sport, so the public acclaim is always going to be a bit limited.

Dont worry, Im expecting to make the same blood sacrifice on sharp edges as everyone else, and if I didnt have a death wish I wouldnt be so keen on doing my own thing with the electronics, rather than using nice standard parts. Id just like to make the machine as safe as I can from my own point of view - being the first death on the circuit would be an extremely embarrassing way to autodarwinate, and not good for the community! (Er, from a press point of view; peoples opinion of me as part of the community may vary...) Isnt the theory that your machine is only likely to be competitive if it scares you witless?

My theory is that the more modes of failure I can compensate for, the less likely my robot is to lose (or kill me). Ill count my paranoia as healthy until such time as I decide I cant bear to be in an arena!

Meanwhile, back on the ranch... using relays for the primary cut-out: isnt there a bouncing issue under severe impact? Id always been biased towards solid-state, but Im prepared to be told this has never been a problem.

--
Fluppet

With Albrights I never encountered any problems with bounce or welded contacts. The SW80 24V B handles 36V with ease, and has a 500A rating for several long seconds before the temperature gets over what Albright sees as lifespanshortening.

In Project One 1 of these did shut down all main power when the single Futaba FS1 failsafe did failsafe.Now the relay itself got fed from the main power.Trough 2 RC switches in series :the first failsafed, the second on a handswitched channel.

I would say the glass or ceramic cut off blade is overenginering, and asking for trouble when relied on that. glass and ceramics do share 1 disadvantage. Those are rather fragile if it comes to shocks RW style.

If you want to be sure, you ad a single 30A car relay ,with a heavy fuse so it can short out when it gets switched on.Then a cheap dependable car relay will smoke, and a fuse will blow. Nothing terminal or expensive.But permanent untill repaired

This may sound like a silly question, but just double checking......
Remote Kill and power light.
Does the power light go OFF when your bot is on remote kill.
Or should the power light ONLY go off when your link is out?
As on paper, you can easily turn remote kill off and kill someone.

Mr Stu

Stu, absolutely not. The power light only goes out when the link is removed. I will have 2 lights, one for link and the other for remote kill / failsafe indication on M2.

Good Good.

Mr Stu

Meant to say: thanks for the suggestion, Mario. Id certainly have to be careful with ceramics (I was thinking in terms of a rubber sheath of some kind - but then realised that this might turn into one of *those* threads if I mentioned it). Id wondered about the fuse route - although its probably harder to engineer, at least to my inexperienced eye. Ill look into it again.

--
Fluppet

I think people shouldnt see a robot in failsafe mode as safe. My robot scared me shitless during series 7, even though I KNEW the failsafes were VERY good. Its still a 5 ton throwing thing on wheels... So even if a robot was remotely killed Id still approach with caution... Robots DO have a tendency to suddenly come to live and stuff... So engineer all you want, but dont forget the power you are dealing with...

WJ, Im glad someone agrees with me, they are not safe when in failsafe mode.

All this talk about robots entering failsafe mode. When on the whole a robot in failsafe is (in my view) far more unsafe that a robot not in failsafe! Think about it... Ok that should be enough time. If a robot has entered failsafe mode then something must have gone wrong therefore it should be treated as if its out of control (because it is) and could set its weapon off or move at any moment. Dont get me wrong they are very important and it no doubt helps with safety.

Getting back to the remote kill. If its going to be used it is an added safety feature but wouldnt it be better if it did exactly what this thread title says, A remote kill, not a remote kill/remote activate. In other words once the remote kill has been activated thats it. The Tx cant retore power. It would be much safer but if it was triggered by accident it would be all over.

Where can you get hold of these albright relays that people have mentioned. (for the UK)
Thanks
Guy

http://www.albright.co.uk/http://www.albright.co.uk/