#robotics Logs

Aug 25 2015

00:13 Anniepoo and which way is it rotating (as in 'wheres gravity')?
00:13 Anniepoo that'll give torque. Then you need to know torque of motor. 8cD
00:14 Anniepoo decide how fast you'll move and compute the dynamic torque
00:17 psYbR around 1.3m long at full extension, lightweight but strong design since the parts are 3D printed but as I haven't finalised the design, assembled it yet or decided on the motors its hard to make an accurate guess. I don't need to it to move quickly, just accurately and with plenty of torque
00:18 Anniepoo morphology?
00:19 niepoo is tempted to next ask for longevity and incept
00:20 psYbR larger version of this http://blogs.msdn.com/blogfiles/gblock/WindowsLiveWriter/MoreWebClientgoodnessshippingWCSF2.0_C95C/Robotic%20Arm_4.jpg
00:21 Anniepoo that thing's nowhere near 1.3m
00:21 Anniepoo 8cD
00:23 psYbR as I said, larger version :)
00:23 psYbR same layout for the joints and end effector though
00:23 Anniepoo ok
00:24 Anniepoo so, t
00:25 Anniepoo t'wer me, I'd build a mockup out of plastic, or make a scale model or something, and get accurate numbers, otherwise you're just guessing.
00:30 psYbR I guess the math is pretty simple... if I multiply the weight of the motor in question by, say, 8 just to be safe, google the torque value and multiply by the gear ratio then look at the moment of force at a radius of roughly 40cm... I should be right as long as the number is positive
00:31 psYbR I wouldn't think the arm would weigh more than about 8 times the weight of the stepper
00:31 Hyratel psYbR, errrrh
00:31 Hyratel you're going to have a bad time
00:31 psYbR lol. why do you say that
00:31 Hyratel because you're making a lot of assumptions about material and weight and force
00:33 psYbR yeah but with a large enough margin for error and with mountains of torque to spare. ideally. if not, I can go the 17: or 27:1 gear ratios
00:33 Hyratel you're new to mechatronics, aren't you
00:33 psYbR yep :)
00:34 Anniepoo 8cD
00:34 Hyratel you run the numbers
00:34 Hyratel then add a Worst Case fudge factor
00:34 Hyratel like +10% weight, -20% torque
00:36 Anniepoo can I ask why you're 3D printing such a large arm?
00:36 Anniepoo (as in 'as opposed to fabricating by some other method')
00:38 Hyratel I've seen a 3D printed pulley that had only compression forces on it split along print seams
00:38 psYbR I thought I did factor in a fairly large margin of fudge. aluminium is expensive, I don't have a CNC, I want to spend very little $ as this robot arm won't actually be useful for anything
00:38 Hyratel plywood
00:38 Anniepoo cardboard
00:38 Anniepoo 8cD
00:38 Hyratel do you have a handsaw? power drill?
00:39 Anniepoo listen to Hyratel
00:39 niepoo has a 1500 sf shop full of CNC gear next to her. She's sanding by hand while doing
00:39 Hyratel nice
00:39 niepoo just finished bandsawing a part she's already laser
00:39 Hyratel you use a hard foam block?
00:40 Anniepoo to sand?
00:40 Hyratel yeah
00:40 Anniepoo sometimes
00:40 Hyratel keeps you from having fingerstripes in the sanding
00:40 Anniepoo in this case I'm preventing splinters. not much more needed
00:41 Hyratel fair nuff
00:41 Anniepoo but yes, a foam block is a good thing.
00:41 Anniepoo I've got a favorite sanding block that's actually a toy 'giant dice' of EVA foam
00:41 Hyratel unrelated, any of y'all heard of/play "Gimbal"?
00:41 Anniepoo nope
00:41 Hyratel I'm looking for more folks to play because the servers are ded dead
03:07 hypodyne howdy.. anyone have an opinion on the inmoov robots?
08:43 rue_school hypodyne, yea I was going to buy 10000 of them for a swarm project and they cost too much
08:49 deshipu kilobots ftw!
09:22 WandHerring Hello
09:25 WandHerring I'm searching general info about drones/multicopter, basic stuff to be able to have a discussion on the topic, does somebody have websites/doc to recommend?
09:26 NonSecwitter Sounds pretty easy... think of something interesting about drones. That's your topic =P
09:27 WandHerring tsss ^^
09:28 WandHerring It's about having a good grasp on the topic, expected technical performance, technology limitations...
09:53 SpeedEvil It also drastically depends if you're looking to use a cooked system, or bake your own using kalman filters et al
09:57 deshipu wolfmanjm: start with wikipedia
09:57 deshipu wolfmanjm: sorry
09:57 deshipu ah, he left
09:57 deshipu sneaky bastard
09:57 eedEvil s
09:57 deshipu so, is "blood curling" like regular curling, only with sharpened stones?
09:59 SpeedEvil On a lake of frozen blood, clearly
11:22 MisterX can some1 plz help me out for a sec? i wanna make a drone, and need some parts.. anyone have suggestions for gps, gsm, gyro and accelerometer?
11:22 MisterX i was thinking of using arduino uno to connect it all
11:27 MisterX i need a good IMU basically xD
12:14 deshipu start by building one of the ready kits
12:14 deshipu then you can play with it
12:14 deshipu and try connecting additional stuff or replacing parts
12:14 deshipu also, it's "quadcopter" not "drone"
12:15 deshipu drone is an automated unmanned vehicle
12:15 deshipu some quadcopters are drones, most are remote-controlled toys
12:19 SpeedEvil remote controlled things may not be toys
12:20 MisterX deshipu, not buidling a quadcopter xD
12:20 MisterX building a self controled vehicle =)
12:21 MisterX controlled*
12:21 MisterX wanted to add commands through GSM
12:21 MisterX and need gps for orientation
12:21 deshipu SpeedEvil: as well as toys may not be remote controlled, I never implied one or the other
12:22 deshipu MisterX: as I said, I would start with taking a ready vehicle, and putting more brains on it
12:23 deshipu that way you only have 100 problems to worry about, instead of 1000
12:24 MisterX and i wanted to test a cool design, but need to test many defferent options
12:24 MisterX it'll look like an insect xD
12:24 deshipu I recommend separating that into two projects
12:25 MisterX it's very many projects hehe
12:25 MisterX it'll have flapping wings too
12:25 MisterX completely done by mechanical cogwheels, only need to spin 1 rod
12:26 MisterX only need 1 motor for each wing
12:26 deshipu there are ready ornitopters out there
12:27 MisterX Very much like those =)
12:27 MisterX i found there are atleast 3 different ways of flying with flapping wings
12:27 SpeedEvil deshipu: If you adjust it so you have 99 problems, then you can write a song about it
12:28 deshipu https://www.youtube.com/watch?v=KXEK2StBiko
12:28 deshipu they have the advantage of actually working
12:29 MisterX birds hit air down and quickly reset their wings, flies gain lift by pusing the wings in any direction
12:29 MisterX and can't remember the last xxD
12:29 MisterX bats
12:29 deshipu squids
12:30 deshipu how about flying pirranhias?
12:30 MisterX of yeah
12:30 MisterX like fish
12:30 MisterX making something that looks like a mermaid xD
12:33 deshipu one hard task at a time
12:33 deshipu seems like you are trying to avoid solving a hard problem by throwing an even harder problem to the bunch
12:34 deshipu that never ends well
12:34 MisterX time.. if we only had enough time.. :-P
12:35 MisterX the problem with birds btw is tht they can't stay still in the air :-/
12:35 MisterX like helicopters
12:35 MisterX but flies can ^^
12:35 SpeedEvil Some birds can hover
12:35 MisterX yeh, but that is very few
12:35 SpeedEvil The harrier, for example.
12:35 MisterX colobri
12:36 MisterX colibri*
12:36 deshipu actually lots of birds can do that
12:36 deshipu most only for short time, as it's exhausting
12:37 deshipu gliding is much better
12:37 deshipu I've seen pidgeons hover
12:37 MisterX true, but colibri can glide aswell =)
12:38 deshipu I'm not sure about that
12:38 MisterX hmm, seen some birds hover for a short while but only when landing and taking off
12:38 deshipu and I suspect flies can't
12:38 MisterX yeh
12:38 MisterX bats are like the UFO of the animals lol
12:38 MisterX doesn't make any sound at all
12:39 deshipu squirrels
12:39 MisterX and the antire body is a wing
12:39 deshipu veverak: can you fly? ;)
12:39 MisterX squirls are cool hehe
12:39 SpeedEvil All flying things make sound.
12:39 SpeedEvil Some are quieter than others
12:39 deshipu especially at the end: *splat!*
12:39 SpeedEvil Sound is inherent in flight.
12:40 deshipu sound is inherent in motion
12:40 MisterX yeh, but bats make so little noise it's almost scary lol
12:40 MisterX when thy fly past your head at night
12:40 MisterX they*
12:41 MisterX birds and flies make Alot of noisewhen flapping their wings
12:43 deshipu only when they want to annoy you
13:00 password2 bats are agile like mad
13:00 password2 yeah a batwing is an amzing thing
13:00 password2 i'v had a bat or two
13:00 deshipu also batmobile
13:06 password2 i wonder what the thickens of a batwing
13:06 password2 the membrane is probably like 0.1mm
13:06 password2 I was always afraid my bat will tear its wing when he cleans it
13:23 veverak deshipu: never tried
13:23 veverak or want to try
13:23 veverak :)