#robotics Logs

Jan 28 2015

00:59 rue_bed those aren't real gears anyhow
00:59 rue_bed they are synchronous wheels
01:00 rue_bed if one turns the other, your good
01:00 Jak_o_Shadows eh, it gets stuck on the side of it
01:01 Jak_o_Shadows Like, it doesn't turn freely
01:06 rue_bed did you think about spacing it out with ashers?
01:07 Jak_o_Shadows one washer still scrapes
01:07 Jak_o_Shadows More might move the hobbings too far
01:19 rue_bed its really easy to be too pickey with these machines
01:19 rue_bed lots of things really dont matter
01:44 Jak_o_Shadows 'spose
01:59 Triffid_Hunter damnit, just smoked a pcb trace on my motor controller
07:27 rudolf_ Hi al
07:27 rudolf_ al*
07:28 rudolf_ I need a motor to operate in position control mode and the torque required is about 55Nm (Newton-metres). Which motor should I use?
07:29 rudolf_ The objective is to mimic human leg motion. Budget not a problem.
07:30 deshipu I would look at the available robotics servos first
07:31 deshipu dynamixel and such
07:32 rudolf_ Can they provide such torques? I have no experience with motors.
07:42 deshipu 560 kg*cm
07:42 deshipu ouch
07:43 deshipu maybe you want to look at hydraulics from a bulldozer?
07:43 rudolf_ :/
07:44 deshipu or rethink your design
07:45 rudolf_ deshipu: The design is fine.
07:45 deshipu if you say so
07:45 rudolf_ Ok what about 30N-m ?
07:46 deshipu that's stil ~300kg*cm
07:46 rudolf_ deshipu: Yea but cant go lower than this. There must be motors for this torque.
07:47 rudolf_ Like this: http://www.robotis.com/xe/DynamixelPro_en
07:47 deshipu the strongest servos I've seen are ~40kg*cm
07:48 deshipu yeah, maybe those
07:48 rudolf_ Its 44 Nm = 440 kg*cm
07:48 deshipu they are way outside my price range
07:48 rudolf_ But I mentioned that I have no budget constraint.
07:49 deshipu so you are basically operating outside my experience :)
07:49 deshipu can't help much
07:50 deshipu even the H54-200-S500-R that you linked seems to max out at 80kg*cm
07:51 deshipu of course you can always trade speed for strenght
07:51 deshipu using a lever or a gearbox or whatever
08:04 rudolf_ ok...thanks anyways
08:29 Veverak is there some nice way to evenly distribute points?
08:30 Veverak WHat I want is this: I have part that acts as "frame" and thus have many mounting points (20 at now?) for screws....
08:30 Veverak so, I need some nice way to distribute that points to parts
08:33 deshipu grid?
08:33 Veverak yeah
08:33 Veverak but want something universal...
08:33 deshipu in what sense?
08:34 Veverak or more like "the more universal it will be, the better"
08:34 deshipu universal with respect to what?
08:34 Veverak https://cloud.veverak.org/public.php?service=files&t=d68adbd33a0dab0285d4550f916d4af1
08:34 Veverak this is actual problem
08:35 deshipu I love when people get to their *actual* problem
08:35 Veverak problem is that I have to create mountings for that parts to that frame
08:35 shipu waits for it to
08:35 shipu waits some
08:35 Veverak but, there will be many parts on the frame "outside", so I need some mountigs for that too
08:36 m_itx waits for deshipu to load it so he can give a full descrip
08:36 Veverak deshipu: to be honest, there is something wrong, the net for that machine should be much better
08:36 Veverak router CAN handle something better :
08:36 Veverak :/
08:36 shipu dismisses the 'unresponsive page' di
08:36 Tom_itx dude, it's you
08:36 Tom_itx not the server
08:37 Veverak anyway, just now I have situation: points are on single plane, one part comes from one side of the plane, second part from the second side of the plane
08:37 Veverak that's what I need solution for
08:37 deshipu Veverak: I assume by points you mean holes
08:38 Veverak buuut, I would be more happy with something for points random in space for as many parts as I want from any side....
08:38 Veverak an:)
08:38 Veverak and I suppose I will figure out something between those two versions
08:38 Veverak deshipu: exactly
08:38 deshipu of course there are nice algorithms for randomly distributing points on a plane, for graphics purposes
08:38 Veverak sounds nice, tips for any?
08:39 deshipu but I fail to see how that would be useful for attaching anything
08:39 Veverak hmm, anything that would always return same result on same piece of data?
08:39 Veverak (random is not wanted here)
08:39 deshipu Veverak: http://bost.ocks.org/mike/algorithms/
08:39 deshipu Veverak: the first few algorithms on that page
08:40 deshipu Veverak: well, pseudo-random with fixed seed then :)
08:40 Veverak I see
08:42 Veverak deshipu: well, idea is that part tells the frame object: "look bro, I am covering you from here to here, and need ... let's say 8 points" and frame will tell: "no problem, here are 8 points to use for you"
08:42 Veverak *inside-part
08:42 Veverak some for outer parts, and it happens :)
08:43 deshipu grid
08:44 Veverak grid?
08:44 deshipu Veverak: what are the constraints?
08:44 deshipu if there are none, then just make a very dense grid
08:44 deshipu of holes
08:44 deshipu one next to another
08:44 Veverak yeah, but I don't want to print 2kgs of material just for frame
08:44 Veverak so I made the thing on the picture.... did yo usaw it?
08:45 Veverak it's compromise between "need as many holes as possible" and "don't want frame with weight of 1/2 of the entire thing"
08:45 Veverak hmm
08:46 Veverak another idea of mine was to mount parts on that tubes between frames
08:46 deshipu no it didn't load
08:46 Veverak hmm
08:46 Veverak deshipu: any tips for free image sharing? :D
08:46 deshipu I don't know, imgur?
08:47 Veverak http://i.imgur.com/9zVKR59.png
08:48 deshipu ok, so you need more domain-specific knowledge
08:48 deshipu what kind of parts?
08:48 deshipu I guess sensors
08:48 deshipu would need much more holes near the edges
08:51 Veverak hmm, outter platting ?
08:51 Veverak :D
08:51 verak still believes there is chance to make it waterp
08:51 Veverak wheels
08:51 Veverak some sensors maybe?
08:51 Veverak deshipu: I don't know exactly
08:51 Veverak that's the point
08:52 deshipu this is something you only get right at the third prototype
08:53 Veverak the idea is to make it universal, so you are relatively free to change the position of things or add them/remvoe them
08:53 deshipu Veverak: for a start, I would research mounting hole spacing of the popular parts you might use
08:54 deshipu Veverak: 2.54mm or 1.27mm would be a good start, probably
08:54 Veverak you know platting ... idea is that between each rib are 4 pieces of platting :D
08:54 Veverak deshipu: got automated plate generator
08:54 Veverak :)
08:55 Veverak *connection palte
08:56 Veverak deshipu: http://imgur.com/e9Og2ED
08:56 Veverak deshipu: you just give it screw positions, "negative" of your part, so it can create holes for it and MAGIC happens -> done
08:57 deshipu kinda like footprints in pcb designs
08:57 Veverak I wanted to somehow make it in a way that you could mount things directly to the frame, but... I suppose it's either "universal mounting" or "mounting plate / adapter"
08:58 Veverak aaand with 3D printer and script getting really smart... the second is the easiest, just for the plate I just give it data and do not have to care
08:58 Veverak deshipu: footprins in pcb? (no experience with pcb)
08:58 deshipu Veverak: make it LEGO-compatible ;)
08:58 deshipu Veverak: lego technic, I mean
08:58 Veverak wow
08:58 Veverak hmm
08:58 Veverak interesting idea :D
08:58 deshipu yeah, you could save on printing of some parts
08:59 Veverak P.S: that tubes -> carbon tubes, not cheapes thing, but I seem them as perfect in terms gain/price
08:59 deshipu aluminium pipes are nice too
08:59 deshipu and much cheaper
08:59 Veverak yeah
09:00 Veverak will see about weight problems :)
09:00 Veverak nuh, that will be long night
09:00 verak plans to create script that will slic3 all parts on model that will be 3d printed, and than calc. weight of everyt
09:00 deshipu you know, in my experience, the best way to get a nice design is just to keep building prototypes until you get it right
09:00 Veverak and also tell me mass center
09:00 Veverak :)
09:01 Veverak deshipu: well
09:01 Veverak mos of the things that you saw are version 3/4
09:02 deshipu well, but you only prototype virtually
09:02 deshipu which is great cost-wise
09:03 Veverak yeah, and because money is not on my side, I will keep with it until I can
09:03 Veverak it's not about just making it
09:03 Veverak everything I use in the script, I try to generalize
09:03 Veverak and make it "tool" for later use
09:04 Veverak so... I am OK with the idea that eventually when I start to build it in real, it will mean a lot of rewriting still :D
09:04 deshipu personally I just started to build them smaller and smaller
09:04 deshipu I noticed the cost grows with size exponentially
09:05 deshipu at ~5cm×5cm I can build them for ~$30
09:05 Veverak I suppose it depends on what your goal is :)
09:05 verak like ... complicated things to be honest, even thou "simplicity" is my ultimate
09:05 Veverak so I like my robot to do a lot of things
09:06 Veverak oh, not complicated... rich in features! :D
09:06 Veverak so it gets more expensive with smalle robots...
09:06 deshipu well, the goal for me is to make an affordable, robust and simple to make quadruped robot for deathmatch-like competitions
09:06 Veverak there is sweet post somewhere in middle
09:06 Veverak deshipu: that sounds nice
09:06 deshipu I really like the idea of Mech Warfare
09:07 deshipu but it's really costly and not very dynamic
09:07 deshipu so I figured that making it smaller, dropping the cameras and using lasers for shooting would let drop the costs dramatically
09:07 deshipu and focus more on the tactics
09:07 deshipu and mobility
09:09 Veverak well
09:09 Veverak I want to create robust, universal, one-time made paltform for things :D
09:09 Veverak with a lot of tools to attach anything to it
09:10 Veverak (one-time print for adapter to hold something is not problem here I suppose)
09:11 Veverak aside that I am learning awesoem amount of things on this
09:12 Veverak (especially because of the things that I want it to be... universal, parametric, automated...)
09:13 GuShH what's with all this steam
09:13 Veverak steam?
09:13 Veverak steam is great!
09:13 Veverak :
09:13 GuShH steam!
09:13 Veverak :)
09:14 GuShH universal... have you thought about meccano? heh
09:15 GuShH slightly modified, call it roccano
09:15 GuShH I shall expect royalties.
09:15 Veverak yeah, too universal
09:15 GuShH Could be in the form of cookies, after all what is money right
09:15 Veverak :)
09:15 Veverak you know, all that terms
09:15 Veverak just relative things :D
09:25 Veverak deshipu: that algorithms webpage of yours
09:25 Veverak that's awesome
09:29 deshipu Veverak: yeah, that's why I had it bookmarked :)
09:30 Veverak anyway, got an idea how to make my script
09:31 verak will pick some start point and pick "n-1 poins" base on the "use the one that is furthest from closest po
09:36 Veverak deshipu: one last thing!
09:36 Veverak for most of the auto-generated things
09:36 Veverak there tends to be "shitty coords"
09:37 Veverak like [0.4343, 6.433, 3.4343454677] for screw posiiton
09:38 verak thought about making some ... sanitizer... like sanitize(vector = [0.4343, 6.433, 3.4343454677], direction = [1, 1, -1]) = [1, 7
09:41 deshipu Veverak: um, I'm not sure what you mean by 'shitty'
09:42 Veverak deshipu: not rounded to mm
09:43 deshipu Veverak: well, why would they be, if you are using spacing that is not full mm
09:44 Veverak hmm, well yeah it depends on context
09:44 deshipu your "sanitization" will mess the dimensions
09:45 Veverak maybe
09:45 Veverak hmm
09:45 Veverak (sanitation for things that are genearted by the script)
09:45 Veverak it will not be auto-sanitazation for everything
09:45 Veverak hmm
10:25 pi- Hello everyone, I'm thinking about making myself an anti-RSI workstation (I've done more coding than sleeping over the last 10 years, and it's becoming unsustainable). Maybe something a little like https://www.pinterest.com/pin/359443613984818357/
10:25 pi- I'm currently looking for some community resource / forum / IRC channel to discuss how to go about making something like this.
10:27 pi- It's going to be mostly structural, slightly mechanical, definitely not robotic, so sorry for OT. But maybe someone here knows of some potentially good place to look?
10:48 deshipu hmm, usability people usually have some experience with ergonomics
10:48 deshipu but #usability is invite-only
10:53 pi- I'm looking for some kind of mini-scaffold (or giant size Meccano) that I could use to make the structure with.
10:54 pi- This must be fairly common in robotics, e.g. making machines for car factories etc...
10:54 DagoRed .shrink
10:54 makepi DagoRed: http://goo.gl/3NikT6
10:54 pi- Any ideas how to Google something like this?
10:55 DagoRed I think I saw that same setup in the movie Grandma's Boy
10:55 DagoRed That might help.
10:58 pi- NEThrone looks fantastic http://www.pcmag.com/slideshow_viewer/0,3253,l=202275&a=202275&po=2,00.asp but apparently that was a scam
13:19 Veverak nah
13:19 Veverak sooo
13:19 Veverak my "screw position picking script" done
13:19 Veverak only thing that is messy is "picking the first screw"
13:20 Veverak for n-set of screws, if you have specific first screw, it always returns same result
13:53 deshipu Veverak: some pairs use a dice for that
13:55 Veverak yeah
13:55 Veverak I have to figure out how to sort my "meta" objects for screws
15:33 Hyratel1 so apparently Extract of Wintergreen makes a good (food-safe!) penetrating oil
19:41 Jak_o_Shadows hmm, a vinyl cutter is just a knife that freely rotates?
19:42 Triffid_Hunter Jak_o_Shadows: I think on some machines they have a motor to set it to the right angle
19:42 Jak_o_Shadows Hmmm