#robotics Logs

Aug 03 2014

03:16 rue_mohr2 but back when I made them, 85? or so, I called it an electromagnetic-piston-inducing-engine
06:50 cambazz hello i am looking for some tank track style rubber threads. a little bigger then the tamiya's default tracks, but not so big.
06:51 cambazz i liked the ones used in surveyor srv1 bot but they are no longer produced
08:12 deshipu https://www.youtube.com/watch?v=jMcDFuaYAug <-- my second crawler
08:16 SquirrelCZECH_ deshipu: genial design
08:18 deshipu SquirrelCZECH_: thanks, I was trying to use as few extra parts as possible
12:36 rue_mohr2 keepsing the parts count down is good
12:37 rue_mohr2 please dont ever do google image stabalization
12:37 rue_mohr2 deshipu, whats the box from?
12:37 deshipu rue_mohr2: ipod shuffle, I thinl
12:37 deshipu think
12:38 deshipu hey, my hands are shaky
12:38 deshipu or some other iProduct that I got as a present and never used
12:38 deshipu but the box is nice
12:39 deshipu but I think you could use anything, even a small plastic jar
12:46 rue_mohr2 tahts the box it came in eh?
12:48 deshipu rue_mohr2: yeah
12:48 rue_mohr2 is it brittle?
12:48 deshipu yay, got it to creep properly, finally!
12:49 deshipu it's the brittle kind of plastic, yes
12:49 deshipu but not extremely
12:49 deshipu it would crack if I stepped on it
12:56 rue_mohr2 fire us a video already
12:57 deshipu it's "processing" :/
12:57 deshipu https://www.youtube.com/watch?v=bo90PsbjNTM
12:57 deshipu here :)
12:58 deshipu that's on 12 fps, it can go faster
13:10 rue_mohr2 nice
13:10 rue_mohr2 what all do you have in the box?
13:10 rue_mohr2 arduino? battery? ??
13:21 SquirrelCZECH you favourite box for electronics/
13:21 deshipu arduino, batter, ir distance sensor (not used yet), a capacitor, lots of plugs and cables
13:21 uirrelCZECH have to hide thi
13:21 SquirrelCZECH you know, reprap stuff
13:22 SquirrelCZECH megatronics, power source, extension borads, cubieboard
13:22 deshipu oh, and a power switch
13:22 deshipu I want to add a bluetooth serial module, when it arrives
13:22 deshipu then I can get rid of the cable
13:23 deshipu the servo plugs and cables take a lot of space, but I didn't want to solder them directly, in case I need to replace or rearrange them
13:26 deshipu rue_mohr2: here is the full bill of materials: http://sheep.art.pl/Micro-Kubik
13:35 rue_mohr2 nicely arranged
13:36 Hyratel1 deshipu, those are some nice drawings
14:10 rue_mohr2 tho not as nice, I suppose I should include my sketches for my robots
14:11 rue_mohr2 nice way of going around having a full arduino shield :)
14:19 deshipu arduino is kinda boring to draw
14:19 deshipu too much detail :)
14:20 deshipu rue_mohr2: but yeah, sketches are definitely interesting
14:20 deshipu they give you insight into the planning process
14:24 rue_mohr2 yea, my sketches show how all over the map my planning is
14:24 rue_mohr2 I lay out about 7 ideas and then hybrid them into what I make
14:24 rue_mohr2 not strictly 7, but many
14:36 Tom_itx how many do you have?
14:36 Tom_itx how many are half completed?
14:45 rue_mohr2 I mean for the same robot
14:45 rue_mohr2 I think I'll inspire from deshipus page and make a collected page for arm...
14:45 rue_mohr2 what am I on now?
14:46 rue_mohr2 for arm 7
14:59 MrCurious someone repost deshipus page link please
15:00 MrCurious you're not giving it to me. give it to me faster...
15:04 deshipu MrCurious: http://sheep.art.pl/Micro-Kubik
15:04 MrCurious ty
15:09 MrCurious i find your design, and re-purposing of available parts clever.
15:10 deshipu thanks
15:10 deshipu the plastic of the horns is a little flimsy
15:10 deshipu but it gives it some ammortization
15:10 MrCurious yes
15:10 deshipu at least I won't strip them
15:20 MrCurious yeah. those tiny blue ones are prone to stripping when worked manually
15:27 deshipu I'm wondering, they have some free space inside the chassis right opposite the pot
15:28 deshipu I could drill a hole in there and put a screw through
15:28 deshipu for a second femur
16:42 rue_mohr2 sweeeet
16:43 rue_mohr2 I was takling to thejester about the vacuum former, and he suggested grabbing the element pack for a dryer, I went down to the scrap metal dropoff and found exactly what it needs
16:43 rue_mohr2 and I got 1 more washing machine valve for the 194 I need for the 12' mecha
16:43 rue_mohr2 at this rate, in 40 years I'll have enough
16:46 deshipu in 40 years we will all get flying mechas for free from google ;)
16:47 deshipu either that, or they will destroy the world
16:51 MrCurious i think the middle east is working on that latter one...
16:57 rue_mohr2 if china has a major natural disaster, its all over
17:02 rue_shop2 when it happens technology will come to a stop
17:07 deshipu or we will build sweat shops somewhere else
17:14 rue_shop2 cant, china now has all the tools and knowhow
17:14 rue_shop2 you cant just create that out of thin air
17:20 monopole not really, all the cool cnc / metal rp stuff comes from germany and japan
17:22 monopole foxconn is having problems putting their 30,000 robots to work... i guess they had the same problems as everybody else.
17:26 rue_shop2 hmm
17:27 deshipu the real question is which other country is willing to get polluted with all the waste coming out of cheap and unsafe manufacturing processes
17:27 rue_shop2 "as the blower started up I briefly notice a can of spraypaint get sucked in, a miraculus cloud of black pait filled the shop and the air"
17:28 rue_shop2 luckily, in real life, It didn't quite get sucked in
17:28 deshipu aw, I always wanted sharp pieces of metal can mixed with toxic paint ;)
17:28 rue_shop2 I'm building arm8
17:28 deshipu is it going to be a hecatonhires (sp?)
17:29 deshipu Hekatonkheires
17:31 deshipu only 92 to go...
17:53 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm7/p1060364.jpg
17:53 rue_mohr2 and I posted sketches
17:53 rue_mohr2 no, not arduino sketches, pencil sketches
17:53 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm7/p1060450.jpg
17:53 rue_mohr2 template for the side
17:54 rue_mohr2 its also the design sketch :)
17:54 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm7/p1060451.jpg
17:54 rue_mohr2 wrist/hand coupler
17:54 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm7/p1060452.jpg
17:54 rue_mohr2 hand frame
17:54 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm7/p1060453.jpg
17:54 rue_mohr2 figuring out how to make the hand
17:55 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm7/p1060454.jpg
17:55 rue_mohr2 designing the wrist joint with belts instead of gears http://ruemohr.org/~ircjunk/robots/arm7/p1060455.jpg
17:56 rue_mohr2 early design stages, proposed dimentions http://ruemohr.org/~ircjunk/robots/arm7/p1060456.jpg
17:56 rue_mohr2 :)
17:57 MrCurious you lost the power man!
17:57 rue_mohr2 say what?
17:58 rue_mohr2 oh I dont like wizard hats
17:59 rue_mohr2 Even if I get to sit on the magic corner stool and gaze into the maw of the all-knowing, none-telling wall
18:01 rue_mohr2 oh, arm8
18:01 rue_mohr2 base http://ruemohr.org/~ircjunk/robots/arm8/p1060365.jpg
18:01 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm8/p1060443.jpg
18:01 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm8/p1060445.jpg
18:02 rue_mohr2 main segment servos
18:02 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm8/p1060446.jpg
18:02 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm8/p1060447.jpg
18:02 rue_mohr2 first segment http://ruemohr.org/~ircjunk/robots/arm8/p1060448.jpg
18:02 rue_mohr2 first segment assembly http://ruemohr.org/~ircjunk/robots/arm8/p1060449.jpg
18:02 rue_mohr2 designing the base frame http://ruemohr.org/~ircjunk/robots/arm8/p1060458.jpg
18:03 Tom_itx you should have a main html for all that
18:03 rue_mohr2 http://ruemohr.org/~ircjunk/robots/arm8/p1060457.jpg
18:03 rue_mohr2 yea, you wannt make one up for me?
18:03 Tom_itx it's pretty easy
18:03 rue_mohr2 thats the template, I'm gonna clean it up and cut two out
18:03 rue_mohr2 actually, I have a php script somewhere that does it for me
18:03 rue_mohr2 I just save the html result as a static page
18:04 rue_mohr2 but I'm building now, not documenting
18:09 Tom_itx what's it gonna do?
18:14 rue_shop2 what do I care
18:14 rue_shop2 unless it does things with legal rammifications, then I'll just pretend I never saw it before
18:18 MrCurious ok, loving this hot air rework for working with hot gllue...
18:31 MrCurious i wonder what gui front end is used to feed commands to marlin... as well as what to use to slice the design
19:07 rue_shop2 slicer and pronterface
19:07 rue_shop2 unrespectivly
19:14 GargantuaSauce_ pronterface is fucking terrible
19:14 GargantuaSauce_ use a different host
19:17 MrCurious http://shop.uberclock.com/collections/smoothie/products/smoothieboard
19:17 MrCurious i think i just found my new cnc machine driver board
19:45 theuberchad hello all. I am looking for information on the Inverse Kinematics for a circular hexapod. Specifically on how to apply the offset to the calculations for the front and rear legs
19:46 theuberchad I believe I have the calculations correct for a linear leg set but I am having issues when trying to apply the 60 degree offset. Any takers?
19:48 GargantuaSauce_ just rotate the whole coordinate system
19:49 GargantuaSauce_ ie rotate the target position by the inverse of the base rotation of the leg
19:49 GargantuaSauce_ then the solution for all legs is identical
19:58 GargantuaSauce_ does that make sense theuberchad? or do you want a diagram
19:59 robotust1a moved from win8 to linux
19:59 robotust1a run my 3dprinter on linux
19:59 robotust1a it was an adventure
20:04 GargantuaSauce_ always is
20:07 MrCurious you could indulge in more retail therapy
20:10 robotust1a fuck, I have to learn Inglish first
20:11 robotust1a you use words which does not fit my brain
20:11 theuberchad Ok that makes sense, I have been trying to figure out the coordinate system, is the center of the robot 0,0 or is based on a leg by leg basis?
20:12 robotust1a they are reflected as ping-pong ball from marble stone
20:12 robotust1a theuberchad: what do you do?
20:12 theuberchad As in what my job is?
20:14 theuberchad sorry Gargantua was AFK, if you had a diagram that would be fantastic!
20:15 MrCurious you need to invoke his name GargantuaSauce_
20:19 GargantuaSauce_ http://www.twiddla.com/1715831
20:20 robotust1a the center of my robot (0,0,0) is in the head between eyes :)
20:21 robotust1a Are you taking cources of group drawings?
20:21 GargantuaSauce_ yes apparently im doing a lesson here
20:21 GargantuaSauce_ thats cool
20:22 robotust1a it's not so clear what are you drawing
20:39 GargantuaSauce_ https://bitbucket.org/Ultrasauce/robots/src/038d0641f7eba422b03b3f1293c8cf4d02a75405/pc/sim_old/IKWalker.cpp?at=master#cl-114 https://www.youtube.com/watch?v=TXvZWTZWN8A theuberchad
20:44 theuberchad So in the case of a tripod gait for example I would have one tripod move to its first location and then rotate around the z axis leaving x and y static for the movement?
20:44 theuberchad and then rinse and repeat for the second tripod?
20:45 GargantuaSauce_ what i did is decouple motion and kinematics
20:45 GargantuaSauce_ the IK solution just moves the leg to an arbitrary point
20:46 GargantuaSauce_ then there's a separate thing that decides where those locations are, in robot coordinates, according to the selected gait
20:47 robotust1a yeah and make a brain with planning to precalculate the next step
20:47 GargantuaSauce_ i didn't bother with that :)
20:48 theuberchad ok, so I think from what you are saying you had the plots for the walking gait determined else where, then calculated the IK angles for the leg, and then translated those IK angles to PWM for the servos?
20:48 GargantuaSauce_ yeah
20:50 theuberchad ok that was where I was heading with it as well. I just had a lightbulb go off when you explained the co-ordinate system. I did have one other question if you didn't mind? and thank you for all your assistance you have no idea how appreciative I am for you taking the time!
20:50 GargantuaSauce_ ya fire away
20:51 theuberchad I was writing my control program in python and was using this for the Angle to PWM conversion: int(((IKAngles[0] + 90) / 180) * 1500) does that look correct to you?
20:52 theuberchad (i have a feeling I am incorrect based on your teachings)
20:52 GargantuaSauce_ nope
20:53 GargantuaSauce_ 1.5ms is the centre point
20:53 GargantuaSauce_ so 1.0 should be 0 and 2.0 should be 180
20:53 GargantuaSauce_ or -90 and 90 if you prefer
20:54 theuberchad so when calculating my angles if they exceed 180 degrees it is wrong
20:55 GargantuaSauce_ well the servos have 180 degrees of travel. you can use arbitrary offsets or whatever for your calculations as long as the end result is in the 1-2ms range
20:56 GargantuaSauce_ my point was more if you plug an angle of zero into that equation you get 750us which will potentially do bad things
20:56 theuberchad yeah did that already, blew on tibia servo doing that by accident
20:57 GargantuaSauce_ you should add a clamping function to the final output so if you screw up the math that won't happen
20:57 GargantuaSauce_ always good to catch NaNs and ridiculously large numbers etc to
20:57 GargantuaSauce_ prevent bad things
20:57 theuberchad yeah next thing I did was put in max and min limit code for the servos, lol
20:57 GargantuaSauce_ http://xn--d-bga.su/deadservo.jpg did this with a floating pointer
20:58 theuberchad eek
20:59 rue_shop2 ya know, I'm not so sure of that
21:00 rue_shop2 what IS that part that burned up, cause it looks like an opto to me
21:00 GargantuaSauce_ it's a fet
21:00 GargantuaSauce_ in so8 package
21:00 GargantuaSauce_ that's half of it.
21:00 GargantuaSauce_ the other half was....liberated
21:00 rue_shop2 why does it look like a surface dip4
21:01 theuberchad so really it should be ((angle + 90) / 180) * 1.5 which should give me the pulse width
21:01 rue_shop2 ah hmm, k
21:01 rue_shop2 and its a hobby servo?
21:01 GargantuaSauce_ 1.5 is the centre point
21:01 GargantuaSauce_ 1.5 + (angle/90*0.5) for -90->90 range
21:02 GargantuaSauce_ yes rue_shop2, the big chunky ones i use in this hex
21:03 robotust1a IMHO robot have to look for it's coordinates itself
21:03 rue_shop2 did you pay more than $10 ea?
21:03 GargantuaSauce_ they were about that
21:03 GargantuaSauce_ HJ S3315D
21:03 rue_shop2 ... hmm whad I just buy from china...
21:03 GargantuaSauce_ and yes i consider it the mark of shit quality for it to have destroyed itself upon receiving a much too short pulse
21:04 GargantuaSauce_ it was pretty impressive, drew like 7A driving into the endstop
21:04 theuberchad wow!
21:04 rue_shop2 S3003
21:04 rue_shop2 how did your circuit allow a servo to pull 7A?
21:05 e_shop2 looks for the tinfoil drawr beside GargantuaSauce_s fuse d
21:05 GargantuaSauce_ because there's 24 of them and i can't limit each of their current individually without quadrupling the size of the electronics
21:05 GargantuaSauce_ i guess individual fuses might be feasible but eh
21:07 theuberchad This was my first attempt at a ripple gait https://www.youtube.com/watch?v=aqJ3Z6OTRpk
21:08 theuberchad using just straight pulse sequences nothing fancy
21:08 GargantuaSauce_ cool
21:09 GargantuaSauce_ whered you get the frame
21:09 theuberchad got it from lynxmotion.com I had found them before when I built my first robot which was a wheeled robot with an arm
21:10 GargantuaSauce_ ah yeah. those guys do cool stuff, pretty pricey though
21:11 theuberchad it was :p bought the chassis and legs weren't too bad but I had to take about 6 months to purchase all the servos I needed.
21:11 rue_shop2 damn, I lost the pvc glue
21:11 rue_shop2 this isn't good, the whole robot is made of pvc (prettymuch)
21:12 rue_shop2 FOUND!
21:13 rue_shop2 http://ruemohr.org/~ircjunk/tutorials/mech/p1010110.jpg
21:13 rue_shop2 this trick is one that a number of people are really starting to like
21:13 rue_shop2 everyone is telling me how that is SO much cheaper than buying pvc sheets
21:14 GargantuaSauce_ can you really get them that planar?
21:16 theuberchad Dropping off now to go to work, but thanks again Gargantua, ill be sure to come back to show progress. You have made my day!
21:16 GargantuaSauce_ good to hear
21:21 GargantuaSauce_ there i did something useful this weekend
22:13 robotust1a GargantuaSauce_: what particularly?
22:13 GargantuaSauce_ helped that dude
22:13 robotust1a :)
22:13 robotust1a that's it?
22:14 GargantuaSauce_ yes :/
22:14 robotust1a I removed fucking win8
22:14 robotust1a installed tons of soft, fixed host controller for my printer
22:14 robotust1a repaired virtual machine
22:15 robotust1a now I have everything ready for work/fun
22:15 robotust1a nealy the same setup I had on win8
22:15 robotust1a but without ugly interface
22:16 robotust1a now I'm printing cups for rods to upgrade printer
22:16 robotust1a wanna do magnet joints
22:18 Tom_itx with what os?
22:20 robotust1a debian
22:20 robotust1a as usual
22:20 robotust1a reoobt
22:20 robotust1a reboot