#robotics Logs

Nov 11 2011

03:21 thylane does anyone ever talk here?
03:23 i_tarzan o/
03:24 thylane you talk, i_tarzan?
03:47 parag0n I dont
03:47 thylane so look slike there some people here
03:47 thylane lets get started
03:47 thylane I would like to see a knock-down-drag-out hostile debate between researchers who support Embodiment versus the guys at the Singularity Institute.
10:25 rue_bed lotsa power flickers latley
10:26 rizlah Apocalipse.
10:26 rizlah Hide yo' kids...
10:26 rizlah /insert usual melodrama here.
10:26 rue_bed na, its a holiday
10:27 rue_bed I fixed the problems with the servomuscle code
10:27 rue_bed didn't have a chance to test it tho
10:32 rue_bed I also got pipe to fix my boiler lines
10:33 rue_bed its exciting to get closer to the actuators I need for hte mecha
10:33 rue_bed I'm gonna be rather impressed if I can pull off the control level I'm after
10:34 rue_bed but so far, everything looks really good
10:34 rue_bed 12' mecha: $240, being the first to get one working: priceless
10:34 rue_bed but we shall see!
10:35 rue_bed maybe I'll go terribly over budget
10:35 rue_bed I know I will if I cant get more washing machine valves
10:35 rue_bed I'm at about 8 of the 188 I need
10:37 rue_bed I need to keep myself focused on the control cage and ff haptic suit tho
10:37 rue_bed esp as it may provide free funding
10:37 rue_bed not much as per how overbudget it is
10:38 rue_bed I think I an come out of it spending only the $120 tho
10:38 rue_bed awefull quiet in here
10:38 rue_bed yes, it is
10:38 rue_bed rue!
10:38 rue_bed rue..
10:38 rue_bed your up
10:38 rue_bed yea, since the power blip
10:39 rue_bed I got stepped on by a cat
10:39 rue_bed million ways to wake up eh?
10:39 rue_bed what do you want to do today
10:39 rue_bed sleep tops my list, but
10:39 rue_bed but?
10:40 rue_bed if you recall SOMEONE decided to go to bed without supper?
10:40 rue_bed oh, hmm, oops
10:40 rue_bed yea, iirc, you said you would make up for it about 2am?
10:40 rue_bed oops
10:40 rue_bed may I suggest we get some food?
10:40 rue_bed later? I'm rather unable to move yet
10:41 rue_bed its 8:30
10:41 rue_bed my point exactly
10:41 rue_bed ugh
10:41 rue_bed shall we see if we can get the boiler controller to boot properly today?
10:41 rue_bed suuuure
10:42 rue_bed roommate finished hte lawn?
10:42 rue_bed so he says, I paid him last night
10:42 rue_bed oh yea,.... I vaugly remember
10:42 rue_bed on other fronts, do you want to take up dvorak?
10:43 rue_bed I'm not sure, its awefull frustrating learning to type all over again
10:43 rue_bed ok, we need to remmeber to get the garbage can back
10:43 rue_bed yes and empty the pop bottles out of the work van
10:44 rue_bed shall we go finish waking up at the desk?
10:44 rue_bed mmmm
10:44 rue_bed your not much help
10:44 rue_bed your fine on your own
10:44 rue_bed less going stircrazy, sure
10:44 rue_bed well I cant speak to that
10:45 rue_bed no, that would be an interesting contradiction
10:45 LoRez rue, you ok
10:45 LoRez ?
10:56 rue_bed I could use some food
11:08 KongfuPanda to make robot?
11:08 KongfuPanda ha ha
11:34 KongfuPanda rue_bed, yes? ;)
11:41 tinyClark anyone know why i can not post in ##electronics?
11:41 hackkitten need to be registered, I think
11:41 Steffanx Yeah indeed
11:41 Steffanx Your nick isn't registred
11:41 Steffanx *registered
11:42 tinyClark just register with freenode?
11:42 Steffanx Yes
11:42 Steffanx /msg nickserv help
11:42 Steffanx /msg nickserv help
11:42 Steffanx oops
11:55 Steffanx You still didn't register your nick tinyClark :)
11:56 rue_house tinyClark, cause they dont want you in there
11:57 Steffanx No it's his nick :)
11:58 tinyClark haha
11:58 tinyClark registered now
12:00 thylane 11:11:11:11:11-11-11-11-11-11
16:29 rue_house oops
16:29 rue_house missed it
16:29 KongfuPanda rue_house, are you the same person behind all of those nicks?
16:29 rue_house which nicks?
16:31 KongfuPanda rue_mohr, rue_shop etc?
16:34 KongfuPanda yeah?
16:36 Steffanx He is
16:37 Steffanx tobbor belongs to him too
16:40 KongfuPanda :D
16:51 dunz0r rue_house: You should invest in a VPS and set up an irc-shell on it :)
16:51 rue_house no I specifically do not want that
16:52 rue_house hmm, well the power outages have thrown me off today
16:53 rue_house need to trim the boot of a few systems
16:53 KongfuPanda what's VPS?
17:15 aggrav8d stupid question: expand (a/b)^2 = ?
17:16 KongfuPanda expand?
17:16 KongfuPanda a^2 /b^2
17:16 aggrav8d (a/b)*(a/b)....
17:16 aggrav8d awesome. just checking.
17:17 KongfuPanda exaaactly
17:17 aggrav8d fighting with my stewart platform all day
17:18 KongfuPanda what's stewart platform?
17:18 KongfuPanda is it like battler robot?
17:18 aggrav8d http://www.youtube.com/playlist?list=PLB010AA8788EA52C1
17:29 aggrav8d check my math on something, please. t = velocity / accel; distance = 1/2*accel * t * t; ergo distance = 1/2 * accel * ( velocity / accel ) ^2; and rearranging we get velocity = sqrt( distance * 2 * accel ); yes?
17:31 KongfuPanda looks nice :)
17:48 rue_house aggrav8d, I realized I have a whole pile of linear actuators, if I wanted I could make one of those platforms your playing with, and try my code out on it
17:52 rue_house the linear feedback would be a bit trickey
17:56 aggrav8d yeah, the potentiometers in my actuators are shit, the results fluctuate by as much as 8%
17:56 rue_house do they have a tiny filter cap?
17:57 aggrav8d better to use stepper motors, encoders, and limit switches
17:57 rue_house .05uF?
17:57 rue_house aggrav8d, on startup, how would you init your actuators?
17:57 rue_house without destroying the platform
17:57 aggrav8d well the system is never in an "illegal" position.
17:57 aggrav8d it can't be - physical constraints and all.
17:58 rue_house o
17:58 aggrav8d so on activation I just drive them to the mid position.
17:58 rue_house ooo you said it right
17:59 aggrav8d the trick is that you have to scale the individual speeds by the distance to go.
18:00 aggrav8d what i mean is, find the actuator that has to travel the furthest (x), the distance this actuator has to travel (y), then scale the speed & acceleration of the actuator by y/x
18:00 aggrav8d otherwise you'll be trying to warp the end effector platform and probably damage your actuators.
18:00 rue_house yea I have an interpolator
18:00 aggrav8d i'm having a really bad couple of days because of that 8%
18:00 aggrav8d trying to hit a target without overshooting? good luck.
18:01 rue_house 8% is pretty bad, is it interaxis nonlinearity or reading instability?
18:01 rue_house my interpolator passes sub control loop off to lower levels
18:01 rue_house it works by issuing the movements in steps
18:02 rue_house its built to be able to synchronize the axies
18:02 rue_house and it works, I used it on one of the arms
18:02 aggrav8d reading instability, i think.
18:02 rue_house instability at what kinda freq?
18:02 rue_house did you try a small filter cap?
18:03 aggrav8d every frame i read the potentiometer. I haven't tried a cap.
18:03 rue_house I usually put .1uF on the pots
18:03 aggrav8d the smallest i have here are 47uF capacitors.
18:03 rue_house aggrav8d, you can get .1uF off any pcb
18:03 rue_house ooo but you dont do that,
18:03 rue_house better make another dk order :)
18:03 aggrav8d i don't even have old PCBs lying around.
18:03 aggrav8d you're not much for social graces, are you?
18:04 rue_house I'm sure $8 and 2 days later you can have it all working great
18:04 rue_house }:] I just find people who are unwilling to scavange funny
18:04 rue_house I have whatever I want within reach at any moment
18:05 rue_house freeeee
18:05 rue_house it gives me the ability to spontaniously create things
18:05 rue_house no working out part lists and ordering and paying and waiting
18:05 aggrav8d you know, I don't come here to discuss your religion.
18:06 rue_house or finding out I forgot soemthing and having to re-order..
18:06 rue_house ya ya, but I do find it funny
18:06 aggrav8d your method works. my method works. can we drop the subject again?
18:06 rue_house ok ok
18:06 rue_house so, tell me if the caps help, I always put them in, but have never really known if I need them
18:07 rue_house I assume I do, cause pots are pretty grindy things
18:07 rue_house but man are they cheap!
18:07 aggrav8d i have to go, gf wants to head out for a walk. first time away from the kb today.
18:08 rue_house mmm good to get out of the house..
18:08 e_house looks out the wi
18:08 rue_house *sigh*
18:55 aggrav8d back
19:28 rue_shop yaya its working
19:28 rue_shop yay
19:28 Tom_itx yay what's working?
19:28 rue_shop valve breaking is at about27 on release and 46 on load
19:28 rue_shop the muscle
19:28 rue_shop I just need some proportionate scaling
19:29 rue_shop if (dead > target){ // release 27
19:29 rue_shop pwm0 = 27;
19:29 rue_shop pwm1 = 0;
19:29 rue_shop }
19:29 rue_shop if (dead < target) { // load 46
19:29 rue_shop pwm0 = 0;
19:29 rue_shop pwm1 = 44;
19:29 rue_shop }
19:36 rue_shop no comments?
19:37 aggrav8d yay?
19:37 Tom_itx sry, i'm kinda nodding off
19:38 home :/
19:39 rue_shop progress on my air muscle code
19:40 rue_shop the scaling of the proportionate error has to be nonlinearly scaled
19:42 rue_shop atop that, the nonlinear scaling for loading and unloading the muscle is different
19:51 rue_house I wonder if I can work out a way to have it work out itself
19:52 rue_house otherwise I'm gonna have to play with paramiters for 188 valves
19:58 home what a valve?
20:02 aggrav8d a valve is a thing that leaks - passwords, cc info, water, air...
20:04 rue_house hahah
20:05 home wow :D
20:05 aggrav8d finally! something approaching success.
20:12 home aggrav8d, nice
20:13 Kimlaroux Lol, nice one aggrav8d
20:22 aggrav8d everything i do is nice! I can't help it if I'm surrounded by philistines.
21:09 home hmm
21:09 home I have Wind River
21:09 home anyone have experience ever using it?
21:14 rue_house aggrav8d, do you have motion sequence you can put on youtube for us?
21:18 Casper ok, trying to make a linear actuator. but I just have a small issue: the threaded rod... how to I keep it from moving out of the motor? bearing and some brackets?
21:19 rue_house !assist projects
21:19 tobbor Possibly http://eds.dyndns.org/~ircjunk/projects
21:20 rue_house http://eds.dyndns.org/~ircjunk/tutorials/mech/actuator/
21:20 rue_house Casper, ^^^^^^
21:21 Casper so yeah bearing...
21:21 Casper now to find a bearing with an hole that fit a #10 threaded rod
21:21 home rue_house, you are hosting this from your house right XD
21:22 rue_house no
21:22 Casper rue_direct drive here however
21:22 home it says dyndns
21:22 rue_house its space donated to me by hackman127
21:22 rue_house yes, the dns record is statically pointed
21:23 rue_house !seen hackman127
21:23 tobbor hackman127 was last seen in #robotics on Jun 29 06:29 2011
21:25 home space? oooh
21:25 home well I gotta start fixing my arm and my gripper.
21:25 home For some reason, my gripper motor keeps reversing.
21:25 home I dont want the motor to BURN out..
21:26 home need to fix the preset..
21:26 home so much to do.. so much to doo XD
21:27 Casper I'ld need to make an hbridge too and optical encoder and bla bla bla :/
21:33 thylane here is a good link for books http://library.nu/
22:03 coppermine so one of the motor controllers worked, the other one is faulty
22:03 home naybe
22:03 home they ysed ti wirj
22:04 home its the controller 0_0
22:04 coppermine what?
22:05 Birdee home, we checked both of the motor and the speed controller
22:06 coppermine will cost me 20$ to ship it back to vegas
22:06 home Birdee, whatever :D BRB
22:06 coppermine not even worth it
22:06 coppermine plus wait another week
22:06 Birdee home, LOL
22:09 coppermine for a 2 wheel robot the movements is simple
22:09 coppermine if i have 4 wheels do i just mimic the 2 extra wheels?
22:10 coppermine i.e turn left both right wheels forward and left backwards
22:10 Birdee coppermine: are you talking four-wheeled drive vs. two-wheeled drive?
22:10 coppermine thats right
22:10 coppermine 4 DC Motors
22:11 coppermine vs 2 DC motors
22:11 Birdee ok
22:13 coppermine so is that right?
22:13 Birdee coppermine: I think the chaining of the wheels would be different
22:14 coppermine ill look it up
22:14 Birdee :)
22:14 coppermine can i still do it if i only have 2 motor controllers
22:14 coppermine hooked up with 2 dc motors each in parallel
22:14 coppermine ?
22:16 Birdee coppermine: are you talking about speed controllers?
22:16 coppermine motor controllers
22:16 coppermine like the pololu 18v15
22:17 coppermine or else i'll have to remove the 2 back wheels
22:18 coppermine and use a caster
22:18 coppermine i need something like this
22:18 coppermine http://www.robotc.net/support/nxt/MindstormsWebHelp/scr/robot_algebra/robot_movements/Robot Movements.htm
22:18 coppermine but for 4 wheels
22:19 Birdee coppermine: are you FLL?
22:19 home Birdee LOL
22:19 coppermine whats FLL?
22:19 Birdee home: ;)
22:19 coppermine oh i got it..
22:19 home LOL LOL
22:19 coppermine just dont turn the other side
22:19 coppermine so if i wanna turn left, the LEFT side wheels FORWARD and right dont move
22:19 Birdee :P
22:19 coppermine this will make a wide left turn
22:20 Birdee yes
22:20 coppermine will the right side wheels get damaged?
22:20 coppermine by not turning?
22:20 Birdee no
22:20 rue_house http://www.robotc.net/support/nxt/MindstormsWebHelp/index.htm#page=robot_algebra/robot_movements/Robot%20Movements.htm
22:20 Kimlaroux thanks rue
22:21 coppermine thats the same link i posted lol
22:21 rue_house forward, reverse, spinright, spinleft, forward right, forward left, reverse right, reverse left
22:21 rue_house as I call them
22:21 Kimlaroux except yours doesn't work
22:21 rue_house my link uses %20 instead of space
22:21 coppermine works fine here
22:21 rue_house not if you click on it in the irc window
22:21 coppermine oh
22:22 rue_house thats ok, thats what were here for
22:22 coppermine so for 4 wheel motors i shouldnt turn all 4 to turn left right
22:22 tinyClark oi! other people that use RobotC, i didnt know you exasted...
22:22 tinyClark haha
22:22 coppermine just one side at a time
22:22 Kimlaroux spaces in html files... *shakes head*
22:22 coppermine cause my wheels dont have direction assistance
22:22 rue_house hmm whats fun to work on
22:22 Kimlaroux coppermine, it's dirty, but it works
22:23 rue_house definitly not a 50 year old reel to reel video player...
22:23 coppermine i'll have to change my .c program
22:23 coppermine not to reverse and forward at the same time when turning
22:23 Kimlaroux the wheels will drag left and right and it won't be good on the bearings, but for a light robot on flat surface... it works. It's just like tracks
22:23 zhanx sup all
22:23 coppermine my robot is about 10 lbs so far
22:24 coppermine Kimlaroux: which method are you talking about?
22:24 coppermine forward on side at a time
22:24 coppermine or forward and reverse both sides
22:24 Kimlaroux you're asking if you can use the same movement method on 4 wheels, right?
22:25 coppermine yes
22:25 Kimlaroux the dirty answer is yes
22:25 coppermine but then i said it might be better to just FORWARD both left wheels
22:25 coppermine and NOT reverse the right wheels
22:25 coppermine isnt that better?
22:25 Kimlaroux hhmm, not really
22:26 coppermine i'll definately use slow speeds to try this out
22:26 coppermine very slow
22:26 coppermine at first
22:26 Kimlaroux well, it depends on what you mean by better
22:26 coppermine not damaging the wheels
22:26 coppermine or motors
22:26 coppermine actually if the motors dont turn it will drag the wheels
22:26 coppermine thats not any better
22:27 Kimlaroux well either way, this will depend on how much traction the wheels will get, and how much stress the bearings of the wheel can take axially
22:27 coppermine dont wanna burn the motors
22:27 coppermine they're 25$ each
22:27 Birdee it's better if the right wheels are reversing, when the left wheels are moving
22:27 coppermine cool
22:27 coppermine so my 1st instinct was good
22:28 Birdee :)
22:28 Kimlaroux http://www.battlekits.com/
22:28 Kimlaroux if your bot is built that heavy duty with wheels with such low traction, then it just don't matter
22:29 coppermine no its not like that
22:29 coppermine im using 0.4" wheels
22:29 coppermine 3 inch diameter
22:31 Kimlaroux but it's the same wheel drive, 4 fixed wheels?
22:31 coppermine yes
22:31 coppermine 4 fixed wheels
22:31 coppermine 4 dc motors
22:31 coppermine 2 motor controllers
22:31 coppermine 2 for each side
22:31 coppermine i mean, 1 controller controlles both left
22:31 coppermine and the other controles both right tires
22:32 Birdee i think that you would need another set of controllers
22:32 coppermine i need to buy a replacement motor contrlller to try it for the 1st time
22:32 coppermine why more controllers?
22:32 Kimlaroux yep, one controller per motor sounds better
22:32 coppermine how is that better
22:32 coppermine if they work together
22:33 coppermine in parallel
22:33 coppermine up to 15A
22:33 coppermine each
22:33 Kimlaroux well, first of, can your controller supply 2 motors?
22:33 coppermine yes
22:33 coppermine pololu suggested i go with 2 instead of 4
22:33 coppermine because it can handle up to 15A for 2 DC motors
22:34 Kimlaroux Current flows through the easiest circuit
22:35 coppermine thats right
22:35 Kimlaroux if you turn and one wheel has more grip than the other, then the current will go trough the motor that's easier to turn
22:35 Kimlaroux and that can lead to weird, unexpected behaviour
22:36 Birdee Kimlaroux, yes
22:38 Kimlaroux think about mechanical differentials, but electric
22:39 coppermine not to damage anything i will only use FORWARD and REVERSE to start
22:39 coppermine until i fully understand turning with 4 motors
22:39 Kimlaroux then you can get some omniwheels
22:41 coppermine http://www.youtube.com/watch?v=HuXDLXcJGfA
22:41 coppermine i think my 1st method is clearly illustrated in this working video
22:41 coppermine both left turn forward, and both right reverse
22:41 coppermine to turn
22:41 coppermine with 4 wheels
22:42 Kimlaroux yep, just like if the wheels on one side where chained together, or a tracked robot
22:42 coppermine exactly
22:42 coppermine chained=in parallel as i said
22:45 coppermine only difference is my tires are not as wide
22:50 Tom_itx still fighting driver problems?
22:50 Tom_itx hmm
22:50 Tom_itx guess he left
23:14 rue_house I might need to backtrack and get a better responce profile for the valves
23:14 rue_house I know I can get pulses that are less than 1 adc units movement
23:16 rue_house hmm
23:17 rue_house making a table and updating it with movement rates for pulse widths every cycle may not work, as the muscles responce changes
23:41 rue_house "If its not there anymore, it means its not dirty. My use of acid to clean stuff is therefore perfectly valid"
23:42 thylane http://www.ruebenstrunk.de/emeocomp/7e.HTM