#robotics Logs

Sep 08 2013

00:36 klander how does it bend?
00:36 GuShH I just told you.
00:37 GuShH look at flex borescopes for hints
00:37 klander so ur saying the outer skin is being twisted and shaped
00:37 klander by the rings?
00:38 GuShH the rings are just joints
00:38 GuShH think ball joint.
00:38 klander he describes the mechanism here: http://www.medscape.com/viewarticle/740524
00:39 klander "It's an articulated computer-controlled probe. It's not being pushed in by a person: There are electric motors that are marionnetting the links of this robot to assume whatever 3-dimensional shape you want, and there are 2 more motors that push the robot in.
00:39 GuShH you can have multiple wires to manipulate it...
00:39 GuShH it is what I said it is, he's just hiding the fact that this is technology older than him and his dad.
00:40 GuShH and it's nothing new on an application point of view
00:42 GuShH klander: start with some thin flexible hose and some steel wire, if your wire is tied at the very top, you can push the wire to bend the arm, you can twist the wire to turn the arm. you get more flexibility by having separate links and multiple wires allows you for better control.
00:42 GuShH it's the same way a flexible magnetic stand works.
00:43 GuShH and even non flexible ones, same principle.
00:43 klander ok but the actual setting of the links, where does that happen?
00:43 klander at the base or at the links position itself?
00:43 GuShH they're following the path of the guide wires
00:43 GuShH without the internal wiring the links would just flop about
00:44 klander okay thats fine but how do u control the guide wire
00:44 klander like how do u get the end of the guide wire to turn upwards
00:45 GuShH torsion and basic torque
00:45 GuShH there are multiple wires not just one. one can define an upward motion, the other could define downward, etc. based on the pull on each, you set where the bend occurs
00:46 GuShH so you twist the wire and the arm bends, as long as there's enough pull.
00:46 GuShH other than that they're all variations of the same idea
00:47 klander interesting
00:47 klander can you point me to some resources or terms that i should be looking for
00:47 GuShH not really
00:49 klander i found this http://research.vuse.vanderbilt.edu/MEDLab/pub_files/WebsterTowardIROS06.pdf
00:49 GuShH ....but you can look at patents of things that behave similarly
00:49 klander "The devices
00:49 klander derive bending actuation not from tendon wires or other external
00:49 klander mechanisms, but from elastic energy stored in the backbone itself."
00:49 GuShH I mentioned borescopes, they're simpler but it's the same principle
00:50 GuShH klander: you could use "muscles" and waste time and money over other stupid designs, sure.
00:51 GuShH it's not something you can build on the cheap, without knowledge.
00:53 klander hmm
00:53 klander thanks
00:53 GuShH look at "muscle wire" as another way of doing it
00:53 GuShH there energy is stored as well....
00:53 GuShH potential energy that is.
00:54 klander shape-memory alloys?
00:54 GuShH right
00:54 GuShH http://www.youtube.com/watch?v=k9f-W6Xi_Wo
00:54 klander those require heating to shape right
00:54 klander inneficient, slow
00:54 GuShH irrelevant to this guy's application.
00:55 klander right
00:56 GuShH a spring can too store energy, whether the initial energy is delivered by a linear actuator or throwing a rock at it, doesn't matter -- as long as it works for you.
00:58 GuShH related http://machinedesign.com/mechanical-drives/thin-section-bearings-sophisticated-machines
00:58 GuShH lol their articles... http://machinedesign.com/embedded/difference-between-industrial-strength-and-low-cost-meters
00:59 GuShH let's compare apples to oranges.
02:09 klander ok so the number of guide wires u need depend on how many joints you want it to have
02:18 SquirrelCZECH guys
02:18 SquirrelCZECH Imagine that I have mechanism which can rotate around one axis
02:18 SquirrelCZECH and there are three cables which go throught
02:18 SquirrelCZECH and I want it to be able to rotate infinite times
02:19 SquirrelCZECH is there some solution?
02:19 SquirrelCZECH P.S: cables to electric motor, so no wireless
02:33 GargantuaSauce_ they're called slip rings
02:38 SquirrelCZECH GargantuaSauce_: what is usual effectivity?
02:41 GargantuaSauce_ depends on the application of course
02:48 SquirrelCZECH slow rotation
02:48 SquirrelCZECH 300W
02:48 SquirrelCZECH (over all three cables together)
02:49 rue_shop2 the ATX supply is push pull, so the 12V winding is centertapped, with each side going thru a diode to the output
02:50 rue_shop2 I can make this 24V is I remove the ground from the centertap, ground one side, and take the other side to two diodes for the resulting +24V and -24V
02:50 rue_shop2 hardest part will be reworking the feedback
04:44 rue_shop2 the hardest part of the reverse engineering was the 4 transistor protection circuit, wholy gazoo!
04:44 rue_shop2 the feedback is DIRT simple
04:44 rue_shop2 it dosn't watch the -5V -12V or 3.3V
04:44 rue_shop2 just 5 and 12
11:16 EpicFail_ hi'
11:18 m_itx doesn't reply so EpicFail_ feels comp
11:20 EpicFail_ oh..
14:18 MrCurious americans and their guns... http://www.desmoinesregister.com/article/20130908/NEWS/309080061/?odyssey=nav%7Chead cant imagine how this could possibly go wrong
14:22 monkers guns are awesome.
14:23 chris_99 why would you arm blind people
14:24 monkers the question is by what right does the government have to take away a disabled persons gun
14:24 monkers some states have vision requirements, some dont.
14:24 monkers they probably should, but, honestly, this is not a problem.
14:24 monkers blind people arent going around poppin kids
14:25 MrCurious i smell a humor opportunity in te next scarry movie...
14:25 MrCurious blind guy trying to shoot a stationary kid to no effect
14:25 chris_99 doesn't it seem illogical for a blind person to own a gun though monkers
14:26 monkers it does but, also the legal definition of blind is probably playing a role here
14:26 monkers since people can be 'blind' but not really no sight blind
14:26 MrCurious could be good for close in home defense
14:26 chris_99 mm true monkers
14:26 monkers yah maybe we're being short-sighted by assuming a gun is useless in the hands of a blind person? (no pun intended!)
14:26 chris_99 lol
14:27 MrCurious i suppose theoretically you could make a CV gun aiming system that used tones to guide the blind... and locks in on people wearing skimasks
14:27 monkers haha
14:27 chris_99 you could then end up shooting harmless people who where just going to go on a jolly skiing outing ;)
14:27 rue_bed "Please describe target"
14:27 monkers "massacre at ski resort"
14:27 monkers yah robocop had that
14:27 MrCurious we already have the gun targeting system that you tag the enemy, and then the gun wont fire til the shot is lined up perfect
14:28 rue_bed no his just aimed for you
14:28 MrCurious i know the perfect title for the movie....
14:28 MrCurious BLIND RAGE
14:28 rue_bed you tag, it bags
14:28 monkers hehe
14:28 rue_bed "Target aquired, please describe where you would like to shoot the target"
14:29 MrCurious would need a knob on the side with settings like police, bad guys, children, LOL
14:29 MrCurious little old ladies
14:29 rue_bed "Say 'favorites' to choose from your saved locations"
14:30 MrCurious a CV aided gun targetting system for the blind would be a great project that would cacuse lots of discussion
14:30 MrCurious suppose a "kill em alll, let god sort it out" setting would be in order
14:31 rue_bed yea, after all, the right to bear arms in the states isn't about T-shirts OR animal slaughter
14:32 rue_bed ok I totally screwed up last night
14:32 MrCurious i never got why we dont have eye tracking shoulder mounted cannons like that creature in teh predator series had
14:32 rue_bed maybe I just never sleep well
14:32 MrCurious did u sleep well?
14:33 rue_bed MrCurious, na
14:33 rue_bed Ihave to get a move on to the things that need doing today
14:33 rue_bed or all the stores are gonna be closed
14:37 MrCurious screws for servo brackets should arrive by tuesday!
14:39 rue_bed m3?
14:40 MrCurious m3x4mm
14:40 MrCurious metric is not widely available here
14:42 rue_bed you just didn't know that all driver transistors are bolted to heatsinks with them
14:42 rue_bed every computer power supply has about 5 just in that, most of them have nuts too
14:43 MrCurious http://www.boredpanda.com/fun-maps-they-didnt-teach-you-in-school/
14:43 rue_bed but a trained engineer will tell you to NEVER re-use a screw/bolt
14:43 MrCurious hmmm just seemed easier to ebay a bag of them
14:44 rue_bed yup, takes longer tho
14:48 MrCurious damn! looks like england almost won the game of risk... invaded every country but 22 of em
15:09 MrCurious http://www.ebay.com/itm/Supper-Micro-ARF-Quadcopter-MWC-Flight-Controller-Multicopter-Motor-Prop-battery-/150974304560?pt=Radio_Control_Parts_Accessories&hash=item2326c51130
15:09 MrCurious priices are dropping
15:11 chris_99 ooooh
15:11 chris_99 that looks fun
15:11 chris_99 is it good?
15:12 MrCurious dont know
15:12 MrCurious all i know is its cheap
15:21 MrCurious nothing shaking here. time for skyrim
16:05 m_itx shakes MrCur
16:08 MrCurious eieieieieiei cut that out
18:24 zhanx_ evening
21:59 MrCurious nice price ... http://www.ebay.com/itm/32-Channel-Motor-Servo-Control-Driver-Board-for-Arduino-Robot-DIY-Biped-Spider-/121169448986?pt=Radio_Control_Parts_Accessories&hash=item1c3643101a
23:29 GuShH MrCurious: quit buying stuff and start making stuff!
23:29 MrCurious hah
23:29 MrCurious its my dormant season while teh weather is too hot to reach my tools
23:29 GuShH lazy fck
23:32 MrCurious bah
23:32 MrCurious make a robot
23:39 MrCurious dont know what it is, but past few weeks, i have not felt like working at home
23:39 MrCurious either weather or work
23:40 MrCurious i know... i changed my home computer from osx to windows8 and now its useless