#robotics Logs

Dec 17 2015

01:35 deshipu well Spot has 3dof legs, it can rotate in place
03:19 stefanopolopolis Hello
03:25 Jak_o_Shadows hi
06:20 anonnumberanon Learning debouncing buttons :) Easy time-consuming process, soothing for the mind :)
07:25 deshipu anonnumberanon: in software or hardware?
07:26 anonnumberanon deshipu, in software
07:33 jhylands anonnumberanon, do you really mean make a push-button a one-shot (so it only fires once when you push it)?
07:34 jhylands deshipu, did you see that quad video from last night?
07:34 deshipu jhylands: the Spot one?
07:34 deshipu it's quite old
07:34 jhylands no
07:34 robotustra morning
07:34 jhylands istruct
07:35 jhylands https://www.youtube.com/watch?v=9xMoXywKyOs
07:35 jhylands its quite old also, but I've never seen it
07:35 deshipu nice monkey
07:36 jhylands yeah, but it has well-defined 4DOF arms/legs
07:36 jhylands I did up an AX-12 version
07:37 anonnumberanon jhylands, im doing two functions, one that sets a flag permanently and one that sets the flag until the button is released. The second function is good if you are trying to naviguate through a list of settings, or turning things on and off, the first is good for a test button that turns on something until you release it.
07:37 deshipu I wonder if it makes sense for a robot to even have a head
07:38 deshipu I mean, for nature, eyes are extremely expensive, so you only have 2 and you have to protect them and reuse them
07:38 jhylands ah, okay - I have a "one-shot" button class (with two methods) that does the one-shot thing without needed continuous polling or interrupts
07:38 deshipu for robots, cameras are cheap
07:38 deshipu you can just have them everywhere
07:39 deshipu and having them fixed to the body actually makes it easier to analyze and integrate the images
07:39 jhylands deshipu, dealing with sensor overload is actually quite difficult
07:39 jhylands I had a robot I built six years ago that had a 1/4 degree resolution LIDAR on it that ran at 40 Hz
07:39 anonnumberanon jhylands, i program most micro applications with real time operating system concepts, i just check everything always at a certain interval, not using interrupts
07:40 jhylands I didn't know about probability theory then, so it was too much to handle otherwise
07:40 jhylands we've come up with really good models for handling stereo vision
07:41 deshipu jhylands: you can always switch between several cameras
07:41 deshipu jhylands: instead of moving the head
07:42 deshipu jhylands: the amount of data is the same then
07:42 deshipu but you have much better and more precise information about the camera's position
07:42 jhylands sure, but you miss out on a lot of important machine-human interactions
07:42 deshipu and fewer mechanical parts
07:43 deshipu jhylands: right, if it's a robot for enterntainment, then you need to mimic humans
07:43 jhylands no, its not just that - we take a lot of visual cues from eye movement
07:43 deshipu but that monkey is supposed to be working in space, if I understood correctly
07:43 deshipu jhylands: that's because humans only have one focus
07:43 deshipu one locus of attention, if you will
07:44 deshipu robots don't need that limitation
07:44 jhylands no, they don't - the cameras don't even have to be mounted on the robot
07:44 jhylands there are lots of UAV swarms that use external cameras
07:45 jhylands when you think about those old clunker round robots that had a sonar array all around them
07:45 jhylands now we just use lidar for that
07:46 jhylands I'm not sure I agree that good stereo camera-pairs (which have to be individually calibrated) fit in the same category
07:47 jhylands besides, you want the cameras to pitch in addition to being able to yaw
07:48 jhylands one thing I think would be very valuable is a camera on each arm/leg, and one on a long flexible tail
07:48 anonnumberanon https://scontent.xx.fbcdn.net/hphotos-xal1/v/t1.0-9/12369262_855564607874515_79985872050175782_n.jpg?oh=6673c56702506dd493f5b4635d27d53f&oe=56D50670
07:51 deshipu anonnumberanon: I have no idea what those words mean
07:51 anonnumberanon :) me neither
07:52 deshipu but that's a lot of thumbs
07:52 anonnumberanon but I can't wait to get 4 hands installed on my body to be able to use that controller
07:52 deshipu I would prefer a flexible tentacle under each arm
07:52 jhylands octo-man
07:52 deshipu lets you save on remodelling all your closthes
07:53 deshipu clothes
07:53 anonnumberanon That's absolutely creepy at best.
07:53 deshipu normally you keep them retracted
07:55 jhylands so anyways, getting back to 3 DOF dog legs, I think spot has the most useful yet still simple morphology
07:56 deshipu yes, with balls for feed
07:56 deshipu for feet
07:57 deshipu it's relatively light at the leg's end too
07:57 deshipu which helps with inertia
07:57 jhylands I'm going to dig up some more of my AX-12s, and build one
07:57 deshipu have you seen the cheetah cub?
07:58 deshipu http://biorob.epfl.ch/cheetah
07:58 jhylands yeah
07:58 jhylands oh, not that one
07:59 deshipu it has 2dof legs
07:59 deshipu but is very sturdy and relatively cheap
07:59 jhylands yeah, but the actuators are probably not simple and cheap
07:59 deshipu they use hobby servos
07:59 jhylands oh, I see
07:59 jhylands with wires
08:00 deshipu animals have tendons too
08:00 deshipu this way the leg is lighter
08:00 jhylands I've played with wire-driven stuff before - its a royal pain
08:00 jhylands if we could encapsulate them like tendons are
08:01 jhylands it wouldn't be so bad
08:01 deshipu bike wires, with whatchacallthem, armor?
08:02 jhylands yeah, I suppose
08:02 jhylands bike wires are a pain to deal with also
08:02 deshipu anything mechanical is a pain ;)
08:03 jhylands well, servos are nice - you set them up, and then don't have to deal with them
08:03 jhylands at least, AX-12 servos are
08:03 vicarion there any technologies that mimic animal muscle closely?
08:03 jhylands although you don't get nice compliance that way
08:03 jhylands series elastic actuators
08:04 jhylands are awesome, but once again hard to build
08:06 deshipu jhylands: have you seen that force-sensing servos recently?
08:06 deshipu with a hal sensor
08:06 jhylands no
08:07 deshipu they guy made them compliant -- he actually programmed a virtual spring
08:07 deshipu with damping
08:07 jhylands cheetah-cub is interesting, but it only goes in a straight line
08:07 deshipu http://hackaday.com/2015/12/15/feeling-force-through-a-servo/
08:08 jhylands that's pretty neat
08:08 jhylands AX-12
08:09 deshipu I tried to do that with measuring the voltage on the motor
08:09 jhylands are supposed to be able to do that
08:09 jhylands but the force sense is more or less broken
08:09 deshipu but I didn't do all the force -> acceleration -> speed -> position integration
08:09 deshipu like he did
08:09 deshipu jhylands: why is it broken?
08:10 jhylands because it doesn't work
08:10 deshipu jhylands: because your won input interferes?
08:10 deshipu own
08:11 jhylands http://www.lukeallen.com/AX12robotlegforce.html
08:11 jhylands read the complications parts (section 5)
08:13 jhylands its not completely broken, but its kindof broken
08:13 deshipu well, that's to be expected
08:13 deshipu it doesn't actually have a torque sensor
08:13 jhylands yeah
08:13 deshipu it just check the current on the motor
08:13 deshipu checks
08:14 jhylands that's why real series elastic actuators are so nice
08:14 deshipu that sensor this guy built is very simple in its final form
08:15 deshipu and I'm thinking, my robot's legs are a bit ellastic anyways
08:15 jhylands would be interesting to see if you could find a rotation spring and some kind of rotation sensor (could even be an analog hall-effect)
08:15 jhylands to build a servo-based one using AX-12's
08:15 deshipu hmm
08:15 deshipu but then you have some flex between the motor and the output
08:16 deshipu which would add lags to everything you do?
08:16 jhylands no, because the motor can sense the flex
08:16 jhylands so it can provide constant force
08:16 deshipu is there even a way to measure force without displacement?
08:16 jhylands you need displacement
08:17 jhylands but the motor can compensate for the displacement
08:17 deshipu interesting
08:19 deshipu I have a bunch of hal sensors, I will have to try this
08:21 deshipu I have to run to watch Star Wars
08:22 deshipu good luck
16:03 Terrenkt rue_shop3, you there?
16:22 akem got my arduino with cdc/cam serial ok, but still some garbage data, wonder about databits/parity/stop i did not touch them
16:22 akem just baud rate kept 9600 on both side, with mik3ys' usb serial lib on android.
16:23 akem could not get the ch340 detected try to add device id/vendor
16:24 akem a little bit anoying since i'll have more of them, just one cdc/cam or maybe the mega
16:25 deshipu try different cable
16:28 akem got only one good usb cable like this here, its shielded also, each read or almost i had my data + few random bytes
16:29 akem i can skip them manually anyway but i guess they shouldn't be around
16:30 akem deshipu what you ve been up to?
16:30 deshipu star wars
16:30 deshipu other than that, the switches for my keyboard came, so I've assembled that
16:31 deshipu https://cdn.hackaday.io/images/382361450349672885.jpg
16:31 akem maybe star wars is good? but ninja turtles looks better am i right?
16:32 deshipu the new star wars is pretty alright -- in the style of the old trilogy
16:32 akem diy keyboard?
16:33 deshipu somehow I never finished watching ninja turtles
16:33 deshipu yeah
16:33 akem cool
16:33 deshipu if you want something exactly how you want, you have to make it :(
16:38 akem deshipu bluetooth?
16:39 akem i have a small rubber bluetooth keyb, i like it
16:39 deshipu akem: usb, I'm a big fan of cables, especially if I type my passwords on it
16:39 akem i need usb gamepad
16:39 deshipu I have a gamepad in the plans too
16:40 akem alright :)
16:40 deshipu so many projects
16:40 akem you got spies around deshipu?
16:40 deshipu no idea, either no, or they are very good
16:40 robotustra_ умутштп
16:40 robotustra_ evening
16:40 akem here is one
16:40 robotustra_ wut?
16:41 akem hey robotustra
16:41 robotustra_ hi
16:43 akem actually its for snes games mainly so dual shock or snes like pad will see later, got no plans to make it myself, i've seen arcade like diy gamepads with large buttons
16:45 deshipu I have two analog joysticsk from a PSP
16:45 deshipu the tiny ones
16:46 deshipu was thinking about making a really small gamepad with those
16:47 robotustra_ а, крича, ты уже знаешь в чем разница между принципиальной и функциональной схемой?
16:47 robotustra_ вот тебе на всякий случай
16:47 robotustra_ https://otvet.mail.ru/question/40024565
16:47 robotustra_ правильный ответ
16:48 robotustra_ sorry
16:48 akem ever wondered what russian keyboards looks like?
16:49 robotustra_ еру ыфьу дшлу утпдшыр
16:49 robotustra_ the same as english
16:49 robotustra_ I type blind both english and russian
16:50 deshipu at the same time
16:50 robotustra_ it's exactly the same as US 102/103 kbd
16:50 robotustra_ forget to switch
21:32 robotust1a evening
21:32 robotust1a fucked up edison and restored it
21:33 robotust1a good experience
21:48 theBear hey rue or rif ! what year was all of us in the same place with the visiting and the international robot meetery ?
21:49 Tom_itx long ago in a far away place....