#robotics Logs

Sep 30 2015

13:37 veverak pbs arrived
14:32 deshipu veverak: great! I was beginning to worry
14:33 deshipu veverak: you didn't have to pay customs?
14:38 veverak nope
14:38 veverak deshipu: so beers for you
15:03 zeehero I blindly typed this channel in, is anyone actually here.
15:04 Snert_ over here
15:16 veverak :D
16:12 ace4016 lol
16:31 deshipu so, guys, have you seen the japanese "smart dolls"?
16:32 deshipu it seems that there is some real progress in building *small* humanoid robots, even when they can't really actually walk
16:34 [cube] neat
16:34 [cube] got a link?
16:34 ace4016 omg...this is going to become Hand Maid May
16:35 ace4016 https://www.youtube.com/watch?v=uzfsSA4FqGw
16:35 ace4016 maybe this isn't what he's talking about though
16:36 ace4016 as i don't see any robots with that
16:38 ace4016 maybe this: https://www.youtube.com/watch?v=GSIw9QWh8kU
16:38 SpeedEvil deshipu: how real are these japanese smart dolls?
16:41 deshipu SpeedEvil: https://www.youtube.com/watch?v=2m_yjmqYlaY <-- looks like at least they have prototypes
16:41 deshipu (that's from 2 years ago)
16:41 ace4016 https://www.youtube.com/watch?v=tNRj2yhy1Nw <-- this has some examples of a motorized version
16:42 ace4016 from last year
16:42 deshipu but there are also hobbyists doing their own attempts
16:44 deshipu and there is also stuff like https://www.youtube.com/watch?v=RPjlJKRa7Uw
16:57 ace4016 not quite sure that's what i'd consider progress
16:58 ace4016 saw a lot of those types of robots a lot in undergrad and that was over 7 years ago
16:58 ace4016 cute though
17:01 SpeedEvil steel hasn't improved
17:01 SpeedEvil And harmonic drives haven't gotten cheaper
17:01 deshipu those use cheap servos and dc motors though
17:02 deshipu I agree that there was little change in quality, but there is a change in quantity
17:02 deshipu and as they become more affordable and popular, change in quality will follow
17:02 deshipu like it did with smartphones
17:04 ace4016 use is what will cause market proliferation
17:04 SpeedEvil yeah
17:04 SpeedEvil There is nothing inherently expensive in a harmonic drive
17:04 SpeedEvil it's just the machining cost kills you if you're making it on general purpose stuff
17:05 deshipu well, it has to be accurate
17:05 deshipu or it will catch
17:05 SpeedEvil Well - yes.
17:05 deshipu but there are less demanding transmissions
17:05 SpeedEvil i'm not saying you can easily make it on inaccurate equipment
17:05 deshipu planetary one is quite nice
17:05 SpeedEvil yes.
17:05 SpeedEvil They pretty much all have issues.
17:06 deshipu hell, for a robot you could use a worm drive
17:06 deshipu you want small speeds
17:07 SpeedEvil Screw that.
17:08 SpeedEvil I want a working Pterosaurus costume.
17:20 ace4016 hehe
17:34 wolfmanjm I have a PWM question.... Should I expect a 50% duty cycle to run the motors at half the speed otr a 100% duty cycle? or is it non linear?
17:35 orlock I would not think you would directly PWM motors?
17:35 wolfmanjm my understanding is that it full duty cycle is 12v, then 50% should be equivalent to runnign at 6v, but I am not seeing that
17:36 wolfmanjm I'm using an Hbridge type motor controller, it has PWM input
18:21 wolfmanjm eh nevermind seems 10KHz is too fast dropped it to 5Khz frequency and all is good as expected. Guess the optoisolators I stuck in there can;t go very fast