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mattmaxsr
Joined: 15 Oct 2011
Posts: 1
Location: Kaliforniastan
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Hello all down under,
I'd love to make it down there someday,
but Maui is as far Southwest as I've gotten!!!
after quick look at this thread
Here's what i can add
I'll give you my feeling about designing a weapon system! YMMV
I love interesting designs (novel, unused techniques, things that are just different) they can be awesome!!! I think Stephen Felk is one of the most interesting builders in the sport, I could look at and play with his bots all day!
BUT that's not how I build, I build with more of a old Chevy/Ford work truck. . . Tough and simple!
Ok back on topic
""I am trying to make a lifter similar to sewer snake for a 30lb robot. I am not trying to throw someone to the roof, but just to lift them as I push them to hit them against the walls. I am trying to get a reasonably fast reacting lifter. Could I use maybe two magnum 550 motors (I think they are 20:1 ratio gearboxes) directly driving a single pivot lifter. If not could you guys point me in a direction of what motor might help me accomplish this design. Thanks.""
Ok I can't help you with motors, haven't used the little stuff.
I will lean towards torque over speed, But this is a system. So if you keep it simple and save weight you can add speed to the torque w/bigger motors.
Remember lifter speed isn't all in the arm!?!? Lifter speed plus bot speed can add up to control!
What I mean is if you attack and can get into a good lift position but you are far from a wall, or you just want to flip them over to get a little advantage for your next attack. Use your bot drive speed to help keep them where you want them while you're lifting/flipping them....
I hope this is understandable.
"". Could I use maybe two magnum 550 motors (I think they are 20:1 ratio gearboxes) directly driving a single pivot lifter""
I don't have any Idea what your bot design is going too look like but this could be a bad idea
(Remember I'm not used to building sub 60 lb.ers so the physics could be a lot different)
but using the gear box as the pivot is looking for a failure point! if you go this route look at shock absorbing components in the mount or arm pivot point.
""* The lifter arm needs to travel much less than 360 Deg. for a lift; I picked 90 degrees for the total arm motion. ""
Nick we aimed for travel radius on PipeWench that would let the lifter travel 3 to 5 deg. below grade (or floor level) and far enough upward movement to be able to self right if/when we get flipped! It turned out for us just under 180 Deg.
""* The lifter arm doesn't need to move all that fast, I figured .25 sec end to end was fast enough and a convenient number to work with.
* 0.25 sec for 90 degrees of movement works out to 1 rps or 60 rpm (I did say it was a convenient number! ) ""
That's funny, I aimed for the same numbers on SS but on PW I figured we had enough power to go a little faster. My reasons at the time was to ensure it would self right, if we move the arm to slow it would just stand on her tail. We wanted a little flick to pop it over. I like the way PW comes off the ground and lands on the tires ready to go when it self rights!
""* The Magnum gearboxes have an output speed of 900 rpm @18v, so they would give you 15 rps or a lift time of .017 seconds; too fast IMHO.""
Can't help you on specs for these I have only worked with Mags, Leasons, and EV warriors
as to the equations dcrobotics and nick posted and their questions on torque and speed is getting into work being done or Horse Power. I'm no engineer but when you mix force with time, things get interesting!!!
I also forgot about Aarons page (lost all my favorites when our PC died)
I used similar numbers to Aarons "TAF" and they seem to work for me.
""In that 2nd equation, what does this bit mean: "(Arm Length [inches] * 16 oz/lb""
Arm length is the distance from the tip to the pivot point or where the axle would be
""16 oz/lb"
Their is 16 imperial ounces (oz.) to an 1 Imperial pound (lbs.)
1 ounce = 28.3495 gram
1 ounce = 0.0283495 kilogram
1 lb, lbs = 453.592 gram
1 lb, lbs = 0.453 kilogram
No I don't know this stuff
www.onlineconversion.com
http://www.onlineconversion.com/weight_common.htm
Hope this wasn't to scatter brained but to much over time and procrastination on bot repairs before an event means little sleep. . .
Good luck with all your designs and I hope my 2 cents gives you some food for thought.
Matt
TPCBots
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Sun Oct 16, 2011 8:36 am |
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