#robotics Logs

Mar 20 2014

00:42 GargantuaSauce are you getting a chunk of robot time between or are you right off to being a slave to the cloud
00:45 MrCurious trying for 2 weeks between to prepare for new job so i look smart day 1
00:46 MrCurious and it will be ages before i acrue usable amounts of vacation again
06:22 Jak_o_Shadows So, initeresting robot hand: http://youtu.be/pW4RcXsZAXc Probably air muscles?
06:27 Jak_o_Shadows at 5:40 a view without the glove.
06:39 chris_99 have you got sound on, i think you can hear air stuff?
06:39 Jak_o_Shadows Yeah, that's where I figured air from
09:30 rue_more its just on/off control, more than likley its a set of air bladders than muscles
09:30 rue_more which is the reason for the glove
09:33 rue_more oh a giveaway wiggle
09:33 rue_more they use those 3d printed fish splines
09:33 rue_more oh
09:33 rue_more or now
09:33 rue_more mnotw
09:35 rue_more its a electropneumatic flexor thing :)
10:08 GuShH_ rue_more: it shows the assembly in the end
10:08 GuShH_ and it's just a grabber hand
10:08 GuShH_ not an anatomically correct one either
10:09 GuShH_ reminds me of those grabby mechanical things
13:32 f00bar80 if i have a continuous rotation servo connected to a 2 beams as to be a robot arm, and it's correctly fixed to the beam but it doesn't move the arm at the time it rotates correctly when not connected to anyting , so this is could be due to which reaosn ?
13:38 f00bar80 even a micro servo do the same
13:39 f00bar80 any idea .. what can be wrong?
13:39 robopal not enough torque?
13:39 robopal I am not sure I understand what you were saying
13:56 f00bar80 robopal, the micro servo supports 1.3Kg.cm and the continuous rotation one supports 5~6 Kg.cm , so could this requires more than the provided kg.cm ? here's the servo how it's connected to the beams https://www.dropbox.com/s/q0kjgezt75nej14/2014-03-20%2020.32.10.jpg
13:57 SlaveToTheSauce lol
13:59 SlaveToTheSauce yeah i suspect you're not going to get very far using those little micro servos for this
13:59 robopal is it really kg per cm?
14:00 SlaveToTheSauce yeah which is roughly 0.1 Nm
14:00 robopal can you lift the arm with your little finger easily or it has some resistance at the contact points where the bolts are?
14:00 SlaveToTheSauce well technically not kg PER cm, kg*cm
14:01 SlaveToTheSauce er, 0.01 Nm
14:01 robopal (loosen the screws, or bolts, however we will call them :D)
14:02 robopal can you hear it trying to move?
14:03 f00bar80 robopal, i have the screws completely loose
14:04 f00bar80 robopal, and yes i can lift the arms with my finger
14:05 f00bar80 robopal, actually the servo lift the arms a bit but not fully
14:06 f00bar80 robopal, https://www.dropbox.com/s/sbqenb6bowxuztb/2014-03-18%2001.49.17.mp4
14:07 robopal it works then? you need to stabilize the one on the base, glue it down
14:08 f00bar80 robopal, but as you can see the one on the top, isn't rotating its full degree
14:09 robopal check one by one dont move both
14:09 f00bar80 robopal, do i need more current supplied to the servo?
14:10 f00bar80 robopal, i did check one by one, and it's the same when i have the one at the top only working
14:10 robopal if you undo the rubber band?
14:10 f00bar80 robopal, actually it seems to be rotating only like 60 degree
14:10 robopal unhook*
14:12 f00bar80 robopal, which one you mean
14:13 robopal do I see a fat one joining the two arms?
14:13 robopal i was thinking maybe it restricts its movement
14:13 robopal it seems so when it powers up
14:14 robopal or is it a cable?
14:14 f00bar80 robopal, no it's just a beam connected the 2 bottom arms and for the top servo lying
14:21 f00bar80 robopal, https://www.dropbox.com/s/dy7mhi0tj2v6u3p/2014-03-20%2020.59.50.jpg
14:21 f00bar80 robopal, so what do you think , the servo isn't power enough or what /
14:28 robopal probably yes, if it does a full rotation with smaller load (shorter length/weight)
14:30 f00bar80 robopal, or it could be more current required
14:30 robopal i do not know
14:30 robopal wait someone else will have a look with more experience on that
14:31 robopal well, dont wait, experiment some more ;p
14:31 robopal I mean, stick around
14:51 f00bar80 SlaveToTheSauce, so what do you think?
14:52 SlaveToTheSauce i think you should examine the mechanical structure of it and what it's doing in detail
14:53 SlaveToTheSauce the top joint is pretty clearly twisting sideways instead of pivoting upwards like you want
14:53 SlaveToTheSauce it needs to be more rigid
14:53 SlaveToTheSauce the servo needs to be mounted to the frame more robustly
14:54 SlaveToTheSauce and the linkage between the servo horns and the beams need to be better also
14:55 SlaveToTheSauce and i suspect the torque of those servos is insufficient
14:58 SlaveToTheSauce i recommend MG996R, you should be able to find them on aliexpress or ebay for ~$10
15:01 SlaveToTheSauce or these http://dx.com/p/193284 http://dx.com/p/193069 which are very powerful but not all that stable
15:01 SlaveToTheSauce http://www.youtube.com/watch?v=2vBi6LNklRg here's those in action
15:29 f00bar80 SlaveToTheSauce, actually while the servo is rotating holding the arm, and it collides the laying arm , it stops
15:32 f00bar80 SlaveToTheSauce, so if it seems to be a torque issue, so it's the same when tried a continuous rotation servo of 5.0~6.0 kg-cm and in that case it didn't move even
17:43 f00bar80 ppl any suggestions?
18:09 rue_more yay! the 16 bit dacs arrived
18:10 rue_more f00bar80,
18:10 rue_more are you having issue with a continious rotation servo?
18:11 rue_more gone
18:15 foobar80 rue_more, firstly can i use it for a robot arm ?
18:16 rue_more not like that no
18:17 rue_more you want continious rotation servos for turning things like wheels
18:17 rue_more that need to rotate continiously
18:17 foobar80 rue_more, as well, how do i know the current it requires http://www.servodatabase.com/servo/feetech/fs5106r , the specs don't tell
18:17 rue_more hmm
18:18 rue_more assume 1A normal max for those servos
18:18 rue_more if you jam it, assume 2A
18:22 rue_more foobar80, this is odd 360 is NOT continious rotation
18:23 rue_more I wonder which is the lie
18:24 foobar80 rue_another, what's odd about it? i've tried to connect it to an arm which rotates 180 , but it actually don't move at the time i think it supports 5kg.cm and this is the arm at the top https://www.dropbox.com/s/dk9le1pububc57g/2014-03-20%2020.58.43.jpg which i'm trying to move
18:25 rue_more they say its a 360 degree, continious rotation
18:25 foobar80 sorry i mean rue_more,
18:25 rue_more this is a conflict, its either 360 degree OR continious roation
18:25 rue_more what does it do when you do not have a robot attached
18:26 foobar80 rue_more, it rotates a different speeds full rotation in a stepper mannere
18:26 foobar80 manner*
18:26 rue_more does it keep turning forever?
18:27 foobar80 rue_another, yea
18:27 rue_more that not what you want for an arm..
18:27 rue_more with continious rotation you cant control position
18:28 rue_more you use continious rotation for wheels
18:28 rue_more things that need to spin
18:28 foobar80 rue_more, i thought it even moves the arm if connected to it , but it's not what happened
18:29 rue_more its much harder for a motor to move a thing than it is for you
18:29 rue_more ^^ that was something I learned early
18:30 foobar80 rue_more, so for an arm like the one in the link , a 6kg is enough to move it ? if yes so this is 5Kg.cm and it doesn't even move it
18:30 foobar80 rue_more, at the time i have the screws compeletly loose
18:31 rue_more I'm trying to think how you can make a better linkage
18:31 rue_more is the one you have now made from a paperflip?
18:32 foobar80 i've use 2 micros, but actually it moves the top arm when it's samy free
18:32 rue_more is the one you have now made from a paperclip?
18:32 rue_more is the servo linkage you have now made from a paperclip?
18:33 foobar80 rue_more, see https://www.dropbox.com/s/bshvidnekd2rdfd/2014-03-20%2022.19.41.mp4
18:33 rue_more is the link made from a paperclip?
18:33 foobar80 rue_more, kind of
18:34 rue_more it might work better if you make a loop on the end of the wire thats attached to the arm, and put a bolt thru the loop to bolt it to the meccano
18:35 foobar80 rue_more, why .. i saw that, but don't know why it might work better
18:35 rue_more thing work better when there is less wiggle int eh connections
18:36 rue_more it would also help to push on the middle between the long pieces than to just push on one side
18:36 foobar80 rue_more, as well , the top arm if you'll see that the micro servo is almost free , and that the only case it can move the arm , if i fix the servo in the meccano the arm doesn't move
18:37 rue_more http://www.the-mobile-factory.com/photos/quiet_ending_mobile_1.jpg
18:38 rue_more have you ever made something like this?
18:38 foobar80 rue_more, https://www.dropbox.com/s/2pmncybw9a9ge49/2014-03-20%2022.20.22.mp4 , you'll notice here what i mean about the top servo
18:38 foobar80 rue_more, no
18:39 rue_more its possable to make things that balance upright
18:39 rue_more if your robot is balanced, it makes the motors work less
18:40 foobar80 rue_more, what do you mean by balance upright ..? how?
18:40 rue_more http://www.pcrobotics.co.uk/images/IRB1400%20trans.png
18:40 rue_more see the spring on that robot?
18:43 rue_more foobar80, it lifts the weight off the motor, if the motor was dissconnected the robot could amost stay up on its own
18:44 rue_more see the top part of the arm? the back is balanced with the front
18:44 rue_more foobar80, do you have any long meccano rods?
18:45 rue_more foobar80, what country are ou in?
18:46 foobar80 rue_more, egypt
18:47 rue_more foobar80, do you have a place to buy bolts and screws?
18:48 foobar80 yes
18:49 rue_more it might help to have bolts as long as your robot is wide, for hinde joints
18:49 rue_more hange
18:49 rue_more hinge
18:49 rue_more :)
18:50 rue_more I'm ill and I need to sleep, I'll be back in a few hours
18:54 foobar80 what do you mean .. didn't get you ... i have bolts with different size long
20:09 GuShH_ rue_more: have you ever tried to cut aluminum with a carbide teeth saw on the skil saw?
20:09 GuShH_ wait I think I should be asking MrCurious instead.
20:10 MrCurious hello
20:10 GuShH_ couldn't find any "for aluminum" discs
20:10 GuShH_ only the 24 or so carbide teeth ones, which I already have
20:10 GuShH_ I think the metal ones have more teeth and are finer
20:10 MrCurious i have cut aluminum on table and chop sasws with aluminum specific carbide blades
20:10 GuShH_ possibly have a different angle too
20:10 GuShH_ yes but otherwise would you get a massive kickback, or what exactly?
20:11 MrCurious they differ from wood blades as the carbide cutter slops negative opposed to normal where wood cutting blads tilt positive opposed to normal
20:11 GuShH_ since carbide is used in all cases, except for diamond tipped... I guess the geometry is what changes, and the amount of teeth
20:11 MrCurious the tooth attack angle is diff for aluminum
20:11 MrCurious and soft non ferrous
20:11 GuShH_ what about ferrous
20:11 MrCurious its more a scrape than a dig
20:11 MrCurious havent done ferous
20:12 MrCurious baby steps, and i am not to ferous yet
20:12 GuShH_ lol
20:12 GuShH_ for ferrous I have the chop saw with abrassive wheels
20:13 MrCurious i am not a trained machinist. every adventure i have i am lucky to escape with only minor bodily damage
20:13 GuShH_ in fact, they work with aluminum but the problem is it heats the aluminum, since it's an abrassive cut.
20:13 GuShH_ not a lot of burr either if the wheel is good quality stuff
20:13 GuShH_ unlike the ones that come with the machines
20:13 GuShH_ they're horrible, useless.
20:15 GuShH_ MrCurious: I wonder if abrassive discs can be used on these skilsaws
20:15 GuShH_ does the arbor match the ones from the big angle grinders?
20:15 ShH_ won
20:15 GuShH_ for ferrous it makes sense to use abrassive cut
20:16 MrCurious good carbide blades for aluminum cutting + wd 40 or a compressed air source will solve the spalting problem
20:17 GuShH_ they had blades for polycarbonate and acrylic...
20:17 GuShH_ but I didn't take a look at the geometry of those
20:17 GuShH_ wonder how they manage not to melt the plastic
20:18 MrCurious http://www.northerntool.com/images/product/2000x2000/336/336024_2000x2000.jpg
20:19 MrCurious though i think my blade has more laid back carbide angles
20:20 GuShH_ couper de l'aluminium oui oui baguette
20:22 GuShH_ hrmmmm there's a "multi-material" one for mdf, plastics and aluminum...
20:22 GuShH_ http://mla-s2-p.mlstatic.com/disco-de-sierra-circular-bosch-184mm-multimaterial-60-diente-5001-MLA4137044878_042013-F.jpg
20:23 MrCurious i am lazy, with patience aluminum blades cut most everything
20:23 GuShH_ I guess I could try one of those
20:23 MrCurious that looks the right blade angle
20:23 GuShH_ but I'll try and fetch one at the local hardware store, bah the one closest to me.
20:23 GuShH_ it claims it's alright for alu, plastics and mdf
20:23 ShH_ sh
20:23 MrCurious but if you are cuting aluminum, make sure to have a air nozzle that is aimed at the blade to keep everything cool and cledar of chips
20:23 GuShH_ I need a finishing one for wood anyway
20:24 GuShH_ I'll take that into account!
20:24 MrCurious that blade would likely burn wood
20:24 MrCurious not agressive enough
20:24 GuShH_ I installed a purge solenoid on my air compressor the other day, wired it today... next step, add an automatic trigger
20:24 GuShH_ Oh I'm saying I need a separate one for finishing.
20:24 GuShH_ the ones I have are for construction work
20:24 GuShH_ they leave a rough edge
20:25 GuShH_ I think the term is "framing" work
20:26 GuShH_ seller says they cut wood just fine... I don't think so
20:26 GuShH_ I bet you're right and it does burn it
20:30 MrCurious think i see a similar effect as using a wood router and moving too slow
20:30 m_itx tries one on GuShH_'s head to
20:31 GuShH_ oh? but once it cut the material, why would the router bit damage the wood?
20:31 GuShH_ unless you mean burnishing
20:32 Curious summons Robu
20:32 GuShH_ ood
20:32 GuShH_ odd*
20:33 MrCurious arent ood the creatures from dr who who resemble cathulu only with suits and light balls
20:33 MrCurious cuthulu
20:33 GuShH_ why are their balls shining?
20:34 GuShH_ or did you cup them and find out they were lightweight?
20:34 GuShH_ found*
20:34 MrCurious they cup their own balls, and wear them on their chest when not in use....
20:34 MrCurious http://demonsrun.files.wordpress.com/2013/09/planet-of-teh-ood.png
20:35 GuShH_ Yeah I remember them, I just didn't know their name
20:38 MrCurious how R OOD
20:39 MrCurious dear god! they weaponized cancer... http://www.theverge.com/2014/3/20/5529084/new-drug-blows-up-brain-cancer-cells
20:59 GuShH_ MrCurious: my dad passed of that.
21:00 MrCurious sorry
21:05 GuShH_ It's OK
21:06 GuShH_ I've seen a few of these "studies" but never anything solid.
21:06 GuShH_ Horrible way to go though.
21:06 GuShH_ It strips you of everything.
21:06 GuShH_ Turns you into a veggie.
21:07 GuShH_ Complete disconnection from the world without being able to do anything about it.
21:08 GuShH_ If I were diagnosed with something like that, I would make a bucket list, finish it... then shoot my brains out before It's too late and it doesn't even let you hold a gun anymore. You don't want to be kept alive for months like that, it's not humane.
21:08 GuShH_ I'm against keeping terminal patients alive, because it's cruel.
21:09 Tom_itx my cousin went that way
21:09 ShH_ is thinking about signing up for organ donor, but it turns out your wish is only carried out if you pass in intensive
21:09 Tom_itx found out he had cancer and blew his head off
21:09 GuShH_ and only in special cases, depending on the circumstance (say a horrible vehicle accident may leave most organs unusable)
21:10 Tom_itx he was a doctor too
21:10 GuShH_ Tom_itx: did he at least enjoy things first?
21:10 Tom_itx i wasn't real close to him
21:10 GuShH_ I won't lie, I would pop a few dipshits first, then I'll have a few drinks and end it... There's no other way in my mind.
21:11 GuShH_ Oh well, if a doctor does it... goes to show, there's no point chasing dragons.
21:11 GuShH_ At least with that specific type of cancer.
21:11 ShH_ slaps MrCurious and changes the subject to Ot
21:13 GuShH_ what's the thinnest MDF they sell?
21:13 GuShH_ does it go down to 3mm or so?
21:13 GuShH_ anything less?
21:13 GuShH_ holy crap 3mm is super cheap
21:16 GuShH_ those reprap kits in mdf have a massive markup
21:18 GuShH_ Tom_itx: actually, going back to that morbid subject... I guess the important thing is not leaving a mess huh
21:20 GuShH_ an owner of a construction yard got diagnosed with something similar... he rigged a forklift with several tons of concrete and decided to stand underneath the load... well the rest needs no explanation.
21:20 Tom_itx no fuss burial?
21:20 GuShH_ it was poetic in it's own way.
21:20 GuShH_ but they leave a mess behind... I guess they don't care.
21:41 MrCurious wow. i seem to have gone through some time dilation field... seems lots of time has passed here, but not from myperspective
23:49 GuShH_ theBear: you around?
23:49 GuShH_ what's going on