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Karmond
Joined: 16 Jun 2004
Posts: 97
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a few design questions...
Now that I've been back for a little while I've been thinking whether or not to actually commit myself to building a bot this time. I do have money to spare and while I'm technically only a box and a couple drills & wheels from having a functional bot made it isn't something I'd be happy about making.
I've been thinking about a design I'd like to build. But I've got a number of questions I'm sitting on at the moment, no doubt I'll have more later on. Some are just to fill me in because I haven't been around for a few years. :p
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How important is left/right weight distribution in a four wheel drive bot?
Assuming I can get away with one battery pack, I won't be able to fit it in the middle. It'll have to go on one side with the space on the other occupied by the speed controller, reciever and the removable link (um, do you even use those?). Nothing there to counter weigh the almost 1kg of a battery pack on the other side even with additional armor.
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How possible/easy is it to build a linear actuar?
If it is possible would something like a BaneBots gearmotor suffice to power the actuator? The actuator would only travel 50mm max. It'll also need to be able to do that in about 1-1.5 seconds. Power required I haven't calculated yet.
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How many MAH in batteries would be needed for ... lets assume 5 RS550 motors at 14.4V
I noticed Glen had done some calculations
here
, I don't know the calculations taken though. If you need the stats for the motor there's some
here
, no idea if they're correct though. :p
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Would it be bad for the battery pack being really close to both the top and bottom armor?
As in, touching... I wouldn't be concerned about flippers due to where the pack is, and even if the bot landed square on it's top or bottom the wheels would hit first.
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What's the general armor & thickness being used for top/bottom armor?
I assume there aren't that many bots with overhead weapons. I'm trying to minimise height, so if say 3mm armor x is as good as 6mm armor y, armor x is better for me.
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What's the general armor & thickness being used for side armor?
So long as it's within my total cost budget and weight limit, I'd be interested. I'm not sure if the same type armor would be used for internal walls though. What do you suggest?
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With skirts, is there a particular ground angle you aim for (i.e. 45 degrees) or is it generally the lower the better?
Thanks.
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Thu Mar 29, 2007 12:31 pm |
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Karmond
Joined: 16 Jun 2004
Posts: 97
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quote:
Originally posted by TDT:
Sounds like Biohazard 
Was I a bit too obvious? :p Yeah it's a biohazard clone, it's the most effective type of design that goes along with the try-and-be-as-low-as-you-can mindset I want.
quote:
Originally posted by TDT:
2. Actuators are fairly easy to build. Bit of threaded rod and a nut and your half way there.
There's a bit more to it than that. I still want it actuatorishly shaped. So I can't just attach arms to the nut and have the rod protruding out of the robot. I'll need an attachment on the nut thingy and have that extending beyond the length of the rod and attach the arms to the end of that. Also do I need to add switches and stuff to it so it stops at a certain position etc. I have a few more questions concerning the way I want the actuators but they can come later.
quote:
Originally posted by TDT:
4. Depends on what your armor is.. If you get hit hard enough, your batteries might get damaged...
They'll be far enough from the sides, I'll just have to watch out for the hammer/axe bots though.
quote:
Originally posted by TDT:
5. It varies with designs. It's more of a case of what you use for the armour and what you can do with it in relation to you design. 3mm polycarb might work on my bot, but 10mm aluminium might not on yours...
Well it's currently a boxish design, invertable, rough estimations are 350mm long by 250mm wide... fair amount of internal walls surrounding the wheels, drive chain, actuators, batteries, speed controller and motors to support the top.
quote:
Originally posted by TDT:
7. Skirts are not that popular these days because spinners just tear them apart like nothing..... Angle wise, I guess you would have to do some testing on that
Ok, fair enough. They could be disposable though. If they just wouldn't work at all I'll have to design angled sides. I was planning on having them attached by a strip of rubber bolted to the skirt and the side of the bot or something like that.
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Thu Mar 29, 2007 3:02 pm |
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Glen
Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
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quote:
How important is left/right weight distribution in a four wheel drive bot?
Assuming I can get away with one battery pack, I won't be able to fit it in the middle. It'll have to go on one side with the space on the other occupied by the speed controller, reciever and the removable link (um, do you even use those?). Nothing there to counter weigh the almost 1kg of a battery pack on the other side even with additional armor.
not at all, ive made a few with distribution that isnt perfect. i.e. controller one side batteries the other and its not really noticable.
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# How possible/easy is it to build a linear actuar?
If it is possible would something like a BaneBots gearmotor suffice to power the actuator? The actuator would only travel 50mm max. It'll also need to be able to do that in about 1-1.5 seconds. Power required I haven't calculated yet.
power yes, reliability of those boxes not so sure of. building a proper linear actuator is tricky. especially at small size. i have a drill one too but thats always at maximum length which is what you where hinting at. you could probably lay the rod flat in the robot and make some sliding mech i guess. something like the new storm2
quote:
How many MAH in batteries would be needed for ... lets assume 5 RS550 motors at 14.4V
I noticed Glen had done some calculations here , I don't know the calculations taken though. If you need the stats for the motor there's some here , no idea if they're correct though. :p
2400s are fine. i use them in all mine are they are all current hungry.
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# Would it be bad for the battery pack being really close to both the top and bottom armor?
As in, touching... I wouldn't be concerned about flippers due to where the pack is, and even if the bot landed square on it's top or bottom the wheels would hit first.
thats all relative. depends how thick the top armour is and what not. on cobra theres barely any gap their, but 3mm steel its not much concern against axes and such. i use thick foam top and bottom along with pretty tough heatshrink to stop them shorting top and bottom.
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What's the general armor & thickness being used for top/bottom armor?
I assume there aren't that many bots with overhead weapons. I'm trying to minimise height, so if say 3mm armor x is as good as 6mm armor y, armor x is better for me.
i use 3mm steel. i think thats about the best compromise of strength and thin-ness. maybe 2mm stainless.
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# What's the general armor & thickness being used for side armor?
So long as it's within my total cost budget and weight limit, I'd be interested. I'm not sure if the same type armor would be used for internal walls though. What do you suggest?
i built kang out of 10mm 5083 and id think thats about as strong as you could make an ali robot before you start going to slanty sides. that gave in after about 5 or 6 events of jolting. so its not all bad. its just too soft. the drums and vert spinners just throw it everywhere. steel for me these days.
cheaper, easier to work with imho, get the tough grades .mild steel is junk in this day and age.  i think the angles are just as important as the thickness. 4mm at 45 degrees is as good as 8mm at 90.
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With skirts, is there a particular ground angle you aim for (i.e. 45 degrees) or is it generally the lower the better?
that will depend on size and weight limitations. i personally agree with aaron about the skirts. better to make the side of the robot solid. weight spent on a strong hinge is better spent on thicker better supported material. lower the better 
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
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Thu Mar 29, 2007 10:27 pm |
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RoboWars Australia Forum Index
-> Technical Chat
mark i suggest you try to get to jeffs this saturday for our next round .
