#robotics Logs

Mar 14 2018

01:45 AM Atomsk is now known as ace4016
03:54 AM z64555: no, I was looking to see if servos had some sort of speed controller in addition to the position controls
03:55 AM Triffid_Hunter: z64555: not really, but you can limit the rate at which you advance the setpoint
03:55 AM z64555: well, yeah
04:39 AM z64555: Anyone with experience with kinematic chains, namely arm manipulators. What kind of math is generally preferred for path planning and tracking? Quaternions, Matrices, or something else?
04:41 AM z64555: I've got a simulator of sorts that uses a mixture, but for the joint/servos it uses quaternions as its target orientation. It doesn't seem to really allow for travel axis constraints.
04:42 AM Jak_o_Shadows: Constraints are hard
08:45 AM SpeedEvil: contact detection, and beep for help
08:48 AM rue_: z64555, speed is position/time
08:49 AM rue_: to control the speed somehting moves at, you control the rate of the position moves
08:49 AM rue_: instead of telling it to get to the destination, you give it a series of positions over a span of time
08:49 AM rue_: I have code if you want it
08:51 AM rue_: so, the glass on my printer broke (again)
08:51 AM rue_: it definitely seems that if I give it enough juice to get to and hold temp, a glass table breaks
08:52 AM rue_: it also looks like everyone is using aluminum beds
08:53 AM veverak: I have great experience with carbon plate
08:53 AM veverak: all printers at company I worked used carbon plate, and they worked perfectly
08:53 AM veverak: however it was never adopted by the community :/
08:58 AM rue_: heh graphine
08:59 AM veverak: it's also practical
08:59 AM rue_: will pla actaully stick to a carbon plate?
08:59 AM veverak: compared to the glass, it does not shatter when you throw it around
08:59 AM veverak: rue_: I did in local hackerspace
08:59 AM * veverak prints ABS, but tried that
08:59 AM veverak: *It did
08:59 AM rue_: huh
08:59 AM veverak: only problem is that the rperap shop that sold it
08:59 AM veverak: is closed
08:59 AM rue_: wouldn't it erode?
09:00 AM veverak: and it's pain in ass to find 200x200mm one
09:00 AM veverak: rue_: what specifically?
09:00 AM rue_: how thick was it?
09:00 AM rue_: 5mm?
09:00 AM veverak: yep
09:00 AM veverak: oh
09:00 AM veverak: wait
09:00 AM veverak: sec
09:01 AM * veverak should have email with item list osmewhere
09:01 AM veverak: Pos. #3 1x Carbon Fibre Plate 200x200x3mm
09:01 AM veverak: Item no. RRS-6832 price per unit: 42,99 Euro Total price 42,99 Euro
09:01 AM veverak: rue_: nope, it was 3mm
09:02 AM rue_: so it was baked
09:02 AM rue_: with something
09:02 AM rue_: today I noticed the wood backing for the pcb heater/glass setup was warping
09:02 AM rue_: nowonder everyone has such a time with bed leveling
09:02 AM veverak: yup
09:03 AM veverak: alu is same pain afaik
09:03 AM veverak: :)
09:03 AM rue_: another reason not to use wood in things
09:04 AM veverak: well
09:04 AM veverak: finally, I trained my 'overseer' at university
09:05 AM rue_: too much carbon fiber stuff out there, cant look for carbon plate
09:05 AM veverak: to buy me things for robots
09:05 AM veverak: \o/
09:09 AM rue_: iooooh graphite plate
09:09 AM rue_: duh
09:09 AM rue_: https://www.aliexpress.com/item/50x50x1mm-high-pure-carbon-graphite-electrode-plate/32754644759.html
09:09 AM rue_: just wrong size
09:10 AM veverak: https://www.aliexpress.com/item/NEW-200mm-X-300mm-X-3mm-Carbon-Fiber-Plate-Panel-Sheets-High-Composite-Hardness-Material-Carbon/32803256022.html
09:11 AM rue_: yea, but its not like I'm gonna spend $100
09:15 AM veverak: yeah
09:15 AM veverak: I understand
09:17 AM rue_: when chromium is not responding, its not taking up 100% of a processor
09:17 AM rue_: so, why is it not responding
09:19 AM veverak: io wait!
09:20 AM rue_: to what?
09:20 AM veverak: dunno
09:20 AM * veverak does not use chromium nor firefox
09:21 AM rue_: I see a lot of port 443 traffic
09:21 AM rue_: when chromium is up
09:21 AM rue_: and not doing anything
09:21 AM rue_: ""
09:22 AM rue_: need a javascript stopper
09:23 AM rue_: google only does 64bit builds
09:25 AM rue_: I wonder how the hell I migrate this system thru the 32-64 bit conversion
09:25 AM rue_: 64bit is stupid, it yields nothing, and takes up more memory doing it
09:26 AM veverak: not true
09:26 AM veverak: :)
09:26 AM rue_: then tell me what the benifit to a 64 bit os is
09:26 AM rue_: go on
09:27 AM veverak: wider channel for communication in the chip, more throughput
09:27 AM rue_: all the memory pointers take up twice as much room
09:27 AM rue_: your turn
09:27 AM rue_: no, the transfer size of instructions is still the same
09:27 AM veverak: well, there is only because you use pointers that take as much memory as they can ;)
09:27 AM veverak: instructions yeas, data no
09:27 AM rue_: you can still use 8 bits if you want
09:27 AM veverak: I have 16bit values
09:27 AM rue_: all the same instructiosn are there
09:28 AM veverak: with 32 bit, vector instructions work with two
09:28 AM veverak: in 64bit with four
09:29 AM rue_: the only time a program needs more than 32 bits to point to the memory its allocated is when its memory-leaking-bloatware
09:29 AM veverak: not really, but whatever
09:31 AM rue_: 32bits if 4.2G of ram
09:31 AM rue_: your saying that a program trying to use more than 4.2G of ram is not bloatware?
09:32 AM veverak: yeah
09:32 AM veverak: simulating galaxy requires more than 4GB of ram
09:32 AM rue_: yea, a human brain requires about 3TB
09:32 AM veverak: half of the caculations done o university where I am require 32GB of RAM and more
09:32 AM veverak: I think there are things that have 256GB servers ?
09:33 AM rue_: thats cause their java bloatware programs
09:33 AM veverak: nope
09:33 AM veverak: that's high optimalized C code
09:33 AM veverak: :)
09:34 AM veverak: in some cases
09:34 AM veverak: of course there are cases with the java bloatware code
09:34 AM veverak: it's eventually only question if the researcher invests into guys that take their code and do it in C/C++ _fast_
09:36 AM rue_: maybe my point is more that a home desktop word-editing, web-browsing computer need not be 64 bits
09:36 AM veverak: true
09:36 AM veverak: but is it profitable to create 32 bits and 64bits procesors?
09:37 AM veverak: or just focus on 64bits?
09:37 AM rue_: I dont know why parsing html requires an 8 core 3Ghz computer with 16G of ram
09:37 AM veverak: (for manufacturers)
09:37 AM rue_: but a 64 bit progcessor has allt eh 32 bit instructions
09:37 AM rue_: the only difference betwen 32 bit and 64 bit os is the size of the memory pointer standards
09:37 AM rue_: SAME COMPUTER
09:37 AM veverak: same goes for software
09:38 AM veverak: why bother compiling 32bits packages? is it profitable? (in any way)
09:39 AM veverak: (if everybody will have 64 bits cpu anyway)
09:40 AM rue_: its better for users and their cost of computer ownership
09:40 AM veverak: P.S: that's why for memory critical code I use custom size pointers
09:40 AM rue_: you get almost 2x the memory efficiency with 32 bit
09:41 AM veverak: I thing it's more like 1.2x
09:41 AM veverak: i don't believe that pointers take all of your memory ;)
09:42 AM veverak: but that depends on app and coding style I suppose
09:42 AM veverak: rue_: I believe that the guys that decide platforms the code is ocmpiled for does not see it that way
09:44 AM veverak: and I agree with them, that it's more practical for them.
01:42 PM z64555: rue_: yes, I do have at least a rudimentary understanding of how controllers work :)
01:42 PM z64555: at least the theory part, I haven't had the funds to buy servos and take them apart for fun
01:42 PM z64555: and when I do it's usually funneled toward something else
07:13 PM rue_: er, $2 servos?
07:13 PM rue_: so you want my speed library or not?
07:14 PM rue_: ooohm, I might have a trapazoidal library too
07:41 PM z64555: no thank you
10:16 PM id4rk_ is now known as id4rk
10:40 PM rue_: so, shop time was a completel waste today
10:40 PM rue_: I got the dc-dc- boost module I needed for a large led light
10:40 PM rue_: got it all set up,
10:40 PM rue_: but the battery that I was using died
10:41 PM rue_: and the low votlage in combo with it trying to drive its fet caused the fet to blow up
10:41 PM rue_: this is the second module I'v killed
10:41 PM rue_: the first one I tried to set the output current by shortingthe output
10:41 PM rue_: but its a boost module, you cant do that
10:42 PM rue_: the output isn't current controlled below the input votlage
10:42 PM rue_: *sigh*