#robotics Logs

Dec 23 2014

00:02 rue_more they are all anchored within 8 inches of the panel
00:02 rue_more not too many are lapped :)
00:31 rue_more ugh, its gonna be a hybrid
00:32 rue_more if anything is gonna break using my method, this will be it
02:10 rue_bed man, the knob came out really nice
02:10 rue_bed this is cool, now I dont have to worry about not having enough of the knob I like for a project
02:11 rue_bed yea, and if the knob I like dosn't have a spinner dimple I can fix taht too!
02:11 rue_bed sweeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeet.
02:13 rue_bed ok, I'll admit that i am finding uses for this printer I didn't think of
02:13 rue_bed sorry, this laptop hasa badspace bar
02:13 rue_bed so I'm getting into the habbit of just hitting it twice
02:14 rue_bed I wonder how I could put knurling on a knob
02:14 rue_bed I bet if I twist the extrusion...
02:17 mrdata thats what she said last night
03:36 Triffid_Hunter rue_bed: for knurling, grab one of the screw thread libraries, subtract a suitable thread then just mirror it and subtract again
03:37 Triffid_Hunter rue_bed: alternatively, make a square-based pyramid and just copy lots of them onto your knurled surface
03:38 Triffid_Hunter rue_bed: there's a fantastic planetary gearbox on thingiverse somewhere with a knurled handle and printed screws and nuts
09:15 rue_more aahhhh
09:16 rue_more the intersection of a left and right hand thread
15:09 Veverak is the guy that wnated to ask something about kalman filters?
15:40 DagoRed hmm?
15:40 DagoRed kalman filters?
15:41 Veverak math stuff
15:48 deshipu mostly for accelerometers and such
15:48 deshipu but could probably be useful for any sensor
15:49 deshipu I still need to write a kalman filter (or at least a low-pass filter) for my robot
15:49 Veverak udacity got quite a nice course containing kalman
15:49 deshipu I've seen it
15:49 deshipu but it's not very practical
15:49 Veverak but anyway, tou can use kalman for a lot of things... where is noise :)))
15:49 deshipu it explains the principle, though
15:50 DagoRed kalman filters over a low pass filter should only be used when you want to reduce delay... and prepare to tune
15:54 Veverak DagoRed: yeah
15:54 Veverak deshipu: yeah, I am pretty damn curious about practical application
15:55 Veverak let's say that state is n=4 vector
15:55 Veverak and that I have multiple sources for sensor measurements
15:55 Veverak :)
15:56 deshipu I have the usual accelerometer + gyro module
15:56 deshipu and I want to know the orientation
15:57 Veverak anyway
15:58 verak would like to be able to put together complete math for robot to... "work" in unknown enviro
15:58 Veverak "static enviroment"
15:58 ace4016 Veverak, robust controls and robust signal processing are both topics that show practical use for kalman filters
15:59 Veverak ok :)
15:59 Veverak ace4016: well, I am practically interested in how to work with calman and matrixes
16:00 ace4016 plenty of that in control systems :D
16:00 Veverak because I've got only some practical knowledge about kalman with one ... value?
16:00 verak is still stu
16:00 ace4016 ah
16:00 ace4016 the first time i really saw kalman filters being used was in one of my control system classes (state space based)
16:01 DagoRed Same.
16:01 ace4016 which tend to be lots of matrices
16:01 ace4016 well...4 in particular :P
16:01 Veverak well
16:01 verak is in 1. year on univer
16:01 DagoRed I don't think one can really work with kalman filters out of state space.
16:01 Veverak and coz it's IT based univerzity, I am afraid I will misss that :/
16:01 DagoRed Sounds like Minnesota.
16:02 verak 's university is mainly SW IT b
16:02 ace4016 well...maybe. i didn't actually see it much until grad school
16:02 DagoRed likewise.
16:02 Veverak nope, Masaryk's univerzity... Czechrepublic
16:02 ace4016 but, you can read about it; you rarely need to be a grad student to understand grad material (though knowing the background math helps)
16:03 Veverak yeah
16:03 Veverak and I found some material
16:03 DagoRed Well from my experience unless you use quaternions it's not worth getting too deap in robust controls.
16:03 Veverak buuuuuut not really ... BFU friendly? or how to say that :D
16:03 ace4016 but yea, books robust control would probably be the most applicable
16:03 Veverak DagoRed: yeah, [x,y,angle] is first step for me :D
16:03 ace4016 i've used them in adaptive signal processing though too so...depends
16:04 DagoRed ace4016: a
16:04 Veverak but I look forward for our ... video processing courses?
16:04 DagoRed Are you more a fan of the EKF's or UKF's?
16:04 Veverak that's interesting too :)
16:04 DagoRed Veverak: Great for tracking algorthims.
16:05 ace4016 DagoRed, don't both have their uses? EKF more for linear systems and UKF for non-linear
16:05 ace4016 ?
16:05 Veverak DagoRed: yeah
16:05 deshipu Veverak: are you in Brno?
16:05 ace4016 i've sadly not touched much control systems stuff for a while so...rusty
16:05 Veverak deshipu: not now, but usually I am :)
16:06 ace4016 hoping to change that in the near future
16:06 deshipu Veverak: are you coming to devconf.cz?
16:06 DagoRed ace4016: I wasn't asking about application, just working with them.
16:06 deshipu Veverak: I'm going to be showing my robots there!
16:06 ace4016 ah
16:06 Veverak deshipu: wow
16:06 verak didn' know it ex
16:06 Veverak well, and you put some motivation to go there :P :D
16:06 ace4016 i've only worked with EKF in the past DagoRed
16:06 deshipu Veverak: I think they do it at your university
16:06 ace4016 so, can't comment much about a comparison
16:07 Veverak deshipu: yeah, it's possible
16:07 Veverak ouch, nope, the other one
16:07 Veverak deshipu: we got two IT Universities in Brno
16:07 Veverak one is more practical, one more theoreticall
16:08 verak is on the theoreticall on
16:09 Veverak deshipu: looking forward to it, it's in my calendar now :)
16:09 Veverak deshipu: btw: heard of base48? Brno's hackerspac
16:09 Veverak e
16:10 deshipu Veverak: yes, of course, they printed the parts for our Prusa Mendel
16:10 Veverak wow :D
16:10 Veverak reminds me that my reprap is not working during christmas, sad :/
16:10 deshipu Veverak: I'm in Poland, Poznań, and we are trying to start a hackerspace here too
16:11 Veverak nice :)
16:11 verak loves that world is not too
16:12 deshipu I was in Brno quite often for the last year, because I had a girlfriend there
16:12 deshipu I like that city very much
16:13 Veverak :D
16:13 Veverak have ever been in Ostrava?
16:13 verak was born and lived so far the
16:13 deshipu no, just Brno and Prague
16:14 Veverak I see
21:26 rue_shop3 FFFFFFFFFFFFFFFFff
21:26 rue_shop3 I used the lathe again while the reprap was going
21:30 rue_shop3 ARG
21:30 rue_shop3 and I just realized that the knobs Im trying to print aren't the right style for this project anyhow
21:30 rue_shop3 FFFFFFFFFFFFFFFFFFFFffff
21:46 rue_more have to design a new knob now
22:14 Tom_itx need help?
22:14 Tom_itx what kind of knob do you want?
22:14 Tom_itx lathe & reprap don't mix well?
22:15 Jak_o_Shadows I wonder how much care you need to do before you can even lightly machine 3d printed parts
22:16 Tom_itx probably not too much
22:16 Tom_itx you would have to treat it like a forging or casting
22:17 Tom_itx where no dimensions are accurate
22:17 Jak_o_Shadows I think you'd need to do something fancy with the infill settings
22:17 Jak_o_Shadows Thicker walls maybe
22:18 Tom_itx well how much machining would you need to do? that would also be planned ahead in the print
22:18 Jak_o_Shadows well, you could turn something to properly round.
22:18 Jak_o_Shadows Drilling holes out?
22:18 Jak_o_Shadows erm, bridges?
22:20 Tom_itx how thin are the current walls?
22:20 Tom_itx if you need to drill alot make the hole bigger to start with
22:21 Jak_o_Shadows well. If the holes are for bolts, you could probably just shove the bolt in and it'll fit. But if you wanted a clearance fit, I'd be tempted to drill it after
22:21 Tom_itx it would be prety easy to cad a custom round knob
22:21 Tom_itx draw a profile and create a spun surface
22:22 Tom_itx rue_more, draw a half round profile and i can create a 3d from it
22:22 Tom_itx pretty easy
22:22 Jak_o_Shadows Blender can do that pretty well even.
22:28 Tom_itx how hard is it to print around objects?
22:28 Tom_itx like imbedded into the part
22:28 Tom_itx probably not that easy given the size of the print head
22:29 Jak_o_Shadows I think that you might be able to put a nut in ifyou left a recess for it? Maybe