#robotics Logs
Nov 14 2015
#robotics Calendar
08:36 robotust1a morning
09:21 becca_KB1WRP morning
09:21 akem hello
09:22 robotust1a becca_KB1WRP: bulding robots?
09:22 becca_KB1WRP always ^_^
09:23 robotust1a what kind of?
09:24 becca_KB1WRP Right now I'm just hacking on a Dawin and a Nao
09:24 robotust1a do you have nao?
09:25 becca_KB1WRP yea
09:25 robotust1a 15k robots?
09:25 robotust1a where did you get them?
09:25 becca_KB1WRP they are 7Kish now
09:25 becca_KB1WRP you know, the web ^_^
09:25 robotust1a anyway a bit expensive for common use
09:26 robotust1a hacking theoretically, or practically?
09:26 becca_KB1WRP practically
09:26 robotust1a is it your own robots?
09:26 becca_KB1WRP trying to get a new OS on the Darwin
09:26 becca_KB1WRP yea
09:26 becca_KB1WRP Trying to get ROS on my Nao
09:26 robotust1a who bought them to you?
09:27 becca_KB1WRP it's strange to you that I can get my own robots?
09:27 robotust1a no
09:27 robotust1a but I would not spend 7k on a toy
09:28 robotust1a and try to break it after
09:28 becca_KB1WRP we are different people
09:28 robotust1a I prefer to spend 7k to build my toy
09:28 robotust1a yeah, you are kind of distructive
09:29 robotust1a actually I build my toy, and hacking it on my way :)
09:29 becca_KB1WRP I do that too, just playing with these at the moment
09:29 robotust1a nice
09:29 robotust1a and what are results?
09:30 Snert there's something creepy about an autonamous companion
09:30 becca_KB1WRP right now I've got ROS running on the nao, been working on the darwin this morning, haven't got the new os to boot yet
09:31 robotust1a but the final goal: how are you going to use them?
09:31 becca_KB1WRP working on developing walking dynamics
09:31 robotust1a is it a final goal?
09:32 becca_KB1WRP real time vision with limited resources
09:32 becca_KB1WRP oddly my final goal is to build a robot cat
09:32 becca_KB1WRP lol
09:32 robotust1a haha
09:32 becca_KB1WRP but I'm working on it's spine right now, and it's taking some effort
09:32 robotust1a my final goal is to make home robot
09:32 becca_KB1WRP my design is using 128 motors just in the spine
09:33 robotust1a I decided to use less
09:33 robotust1a on the backbone
09:33 becca_KB1WRP you're going to have an articulated spine
09:33 becca_KB1WRP not many people do
09:34 Snert a vertical snakebot.
09:34 robotust1a not so flexible
09:34 robotust1a this is a sketch what I gonna do http://imgur.com/xZEKXIT
09:34 becca_KB1WRP cat has 3 spine segments
09:35 becca_KB1WRP cute ^_^
09:35 robotust1a the same as for all mammal animals
09:35 becca_KB1WRP oh really, I didn't know that
09:36 robotust1a and it's not just coinsidence
09:37 robotust1a I also gonna do flexible neck and kind of flexible loin
09:38 robotust1a what motors do you use for spine articulation?
09:38 becca_KB1WRP thinking about winding my own
09:39 robotust1a actually I also designed my own, but didn't made it yet
09:40 robotust1a just repaired my 3d printer, may de start to do one
09:43 robotust1a so, you have 2 robots to play with and 1 to build?
09:43 robotust1a or you are already started?
09:45 robopal can I ask something out of curiosity, how much money do you guys spend on robotics on average on a monthly basis? covering tools, materials, outsourcing if any (like pcbs), etc?
09:46 robotust1a I spend about 100-150 $
09:46 robotust1a 100 in average
09:47 robopal you bought some tools in advance or you buy as you go what you need?
09:47 becca_KB1WRP I'm in a design phase right now, so pretty much nothing
09:47 becca_KB1WRP I buy as I go
09:48 robotust1a yeah, the same for me
09:48 robopal do you have access to any public lab/shop where you can do little work?
09:48 robopal like hackerspace for example
09:48 robotust1a buy parts, or materials, process, and do another iteration
09:49 robotust1a I have cnc mill at home and 3d printer
09:49 robotust1a actually I don't need any hackspace
09:49 robotust1a I'm not sure I can build something like I want in hackspace
10:01 LiohAu robotust1a: you're pivot thing that replaces the knees
10:01 LiohAu did you determine the torque needed for the motors here ?
10:02 robotust1a not yet exactly, but they will be mainly holding position. I'll use harmonic-like drive
10:03 LiohAu robotust1a: its was you yersteday that was asking for harmonic drive motors?
10:03 robotust1a this one https://www.youtube.com/watch?v=POSKD3lSD8E
10:03 robotust1a I was asking about DC motor to drive it
10:04 LiohAu your thing is a cycloidal gear reducer?
10:04 robotust1a yes
10:05 robotust1a 1:84 about
10:05 robotust1a I gonna use them in knees and hips
10:05 LiohAu I never head about this kind of reducer
10:05 robotust1a youtube it
10:05 LiohAu is it new? or patented ?
10:06 LiohAu I mean, how is it possible that I never saw that word oO
10:06 robotust1a patented? are you kidding me?
10:06 robotust1a https://www.google.ca/search?q=cycloidal+drive&espv=2&biw=1680&bih=919&source=lnms&tbm=isch&sa=X&ved=0CAcQ_AUoAmoVChMI-828q6CQyQIVRR0eCh1r0AtS
10:06 LiohAu I have been looking at motors the full week to find one that fits, and in the datasheet I saw all kind of gears, and never saw anything about cycloidal drive :(
10:07 robotust1a now you know
10:08 LiohAu robotust1a: just to confirm, it's not the same thing as planetary or spur or harmonic? it's a 4th type ?
10:10 robotust1a don't know twhat is spur
10:10 robotust1a harmonic drive is patented
10:11 LiohAu harmonic drive is really expensive
10:11 robotust1a and it's difficult to make it at home
10:11 robotust1a cycloidal drive is much more simple
10:12 LiohAu well how would you compare cycloidal to planetary ? efficiency is better ? or it's just a matter of space and/or weight ?
10:14 robotust1a cycloidal is more simple
10:15 robotust1a what's inside my drive http://i.imgur.com/GbzoJjB.jpg
10:15 LiohAu and you don't get backlash,
10:15 LiohAu ?*
10:15 robotust1a planetary is more complex
10:15 LiohAu because one of the advantage of harmonic is 0 backlash
10:16 robotust1a I havent
10:16 LiohAu Wikipedia : "Unlike many other drive mechanisms the cycloidal drive is not typically backdrivable. Due to the eccentric nature of the drive, if the cycloidal disk is not balanced by a second disk or a counterweight, it will generate vibration which will propagate through the driven shafts. This will cause increased wear on the exterior teeth of the cycloidal disk, as well as component bearings."
10:16 robotust1a but plastic could whear
10:16 LiohAu you're from CA ?
10:16 robotust1a no, CAnada
10:16 LiohAu sorry that was I meant :P
10:17 LiohAu forgot that CA refers to california :D
10:17 robotust1a :)
10:17 LiohAu do you speak french?
10:17 robotust1a no, I know it but use it rarely
10:17 LiohAu ok
10:17 LiohAu (i'm from france)
10:18 robotust1a too much languages in my poor head
10:18 LiohAu I prefer C :P
10:18 robotust1a je peur parler un peu
10:18 robotust1a mais mon ecris est movais
10:19 LiohAu "écrit" "mauvais" :P
10:19 LiohAu but the sounds is good ^^
10:19 robotust1a yes sure
10:20 robotust1a actually I studied it for 2 years before came to quebec, but after that use it in shops only sometimes
10:20 robotust1a and this drive I did is not exactly cycloidal - it's bidirectional
10:21 LiohAu and so you're good in mechanics only?
10:21 LiohAu or electronics and software too?
10:21 robotust1a it works like harmonic drive bit keep only one point in contact
10:21 robotust1a in electronics and software and in firmware too
10:22 LiohAu ok you're ready for robotics so ^^
10:22 LiohAu i'm only good in software :(
10:22 robotust1a the principle
10:22 robotust1a http://i.imgur.com/qLU0frh.jpg
10:22 LiohAu well this looks like harmonic, no?
10:22 LiohAu or harmonic is not a circle, but more ovaloid?
10:23 robotust1a harmonic has 2 points of contact
10:23 robotust1a but yes it's similar principle
10:23 LiohAu you have a good printer
10:23 LiohAu or maybe the part is big?
10:23 robotust1a 78 mm outer diameter
10:24 robotust1a printer is not bad
10:24 LiohAu well your printer is good ^^
10:24 LiohAu I have a flashforge one
10:24 LiohAu quality is "correct"
10:24 LiohAu but I don't think that I can use it to make gears
10:25 robotust1a I got Rostock Max v2 kit
10:25 LiohAu reprap ?
10:25 robotust1a delta
10:25 Tom_itx rails?
10:25 robotust1a http://seemecnc.com/products/rostock-max-complete-kit
10:25 robotust1a yeah
10:26 LiohAu talking about the guide?
10:26 robotust1a good printer if handle with care
10:26 LiohAu and you're working alone on your robot?
10:27 robotust1a yes
10:27 LiohAu because imo this is too big for 2 or 3 people
10:27 Tom_itx yeah you need a comittee
10:27 LiohAu only the sketched hand would require 1 or 2 people
10:27 robotust1a I plan to build it in 3-4 years from here
10:28 robotust1a I did it myself in 1 week
10:28 LiohAu the hand?
10:28 robotust1a yes
10:28 LiohAu well you took some 3d printed existing thing, no
10:28 LiohAu ?
10:28 robotust1a no
10:28 LiohAu or you made it from scratch in one week?
10:28 robotust1a I designed them myself
10:28 LiohAu so you have CAD skills too? :P
10:28 robotust1a yep
10:29 Tom_itx what cad?
10:29 LiohAu catia?
10:29 ace4016 cadbury eggs
10:29 robotust1a russian cad
10:29 Tom_itx i use catia
10:29 robotust1a t-flex
10:29 Tom_itx solidworks
10:29 Tom_itx smartcam
10:29 Tom_itx acad
10:29 robotust1a I just stick with t-flex
10:29 LiohAu well I only use solidworks, and i'm already fighting to make the ball screw :(
10:30 Tom_itx what ver?
10:30 LiohAu 2016
10:30 LiohAu they added a lead screw feature, but nothing for ball
10:30 robotust1a all this done in t-flex http://i.imgur.com/VqJOAax.png
10:30 LiohAu I guess thread is not exactly the same
10:31 LiohAu but your hand has not actuators oO
10:31 LiohAu or there are cables in the 2 black tubes?
10:31 robotust1a I'm not too skilled to put actuators
10:31 robotust1a I just wanted to see proportions of skeleton
10:32 LiohAu ok, but did you think at them? :)
10:32 robotust1a actuators - I'm not going to draw them - too complex
10:32 robotust1a of cause
10:32 LiohAu because they are usually heavy, and with the tube you're using, I guess the only way is to put them in the torso
10:32 robotust1a and all joints will be more complex, it's just a draft
10:33 LiohAu anyway I think you should simplify ^^
10:33 robotust1a I will
10:34 robotust1a it's just version 1
10:34 Tom_itx you'll be too old by the final ver
10:34 robotust1a not older than you naw :)
10:34 robotust1a now
10:34 Tom_itx i'm young
10:35 robotust1a anyway I need to do something till the day I die :)
10:35 LiohAu i'm working on a SCARA arm, only the shoulder TZ/RZ DoF actually, and it's already a nightmare
10:35 LiohAu moreover as I'm really bad in mechanics I waste hours to find the appropriate formulaas
10:36 robotust1a what is SCARA arm?
10:36 robotust1a 3 stepper motors?
10:37 LiohAu no I don't want steppers
10:37 LiohAu I want to use brushed motors with encoders
10:37 LiohAu steppers would be the easy way :P
10:38 Tom_itx harmonic drive?
10:38 LiohAu no
10:38 LiohAu i'm poor
10:38 LiohAu that will look like this : http://imgur.com/5pGZIA0
10:38 LiohAu (yes i'm worst than you in drawings :P)
10:38 LiohAu (and as you can see i'm trying to determine the torque for the motor at the bottom) :P
10:39 Tom_itx http://www.users.qwest.net/~kmaxon/page/side/robot1_137.htm
10:39 Tom_itx just like that?
10:39 robotust1a it's easy to calculate
10:40 robotust1a Tom_itx: the first 90 years pass fast?
10:40 Tom_itx he's not 909
10:40 Tom_itx 90*
10:41 robotust1a I mean you
10:41 Tom_itx i'm not either
10:41 LiohAu robotust1a: if I ignore the bevel gears, ignores efficiency issues ... is it 2kg * 9.8 * 70cm = 13,72 Nm ?
10:41 Tom_itx i'm young
10:42 robotust1a how old are you?
10:42 Tom_itx 13
10:42 robotust1a I saw you on your videos
10:42 LiohAu haha
10:42 robotust1a you are older than me
10:42 Tom_itx you've never seen me in a video
10:43 robotust1a I'm 14
10:43 Tom_itx maybe a hand
10:43 LiohAu well the skin on the hand helps to determine the age.
10:43 robotust1a shaking oldery hand
10:43 LiohAu Look at all those lifted actors, you can determine their age with the skin of their hand :P
10:44 robotust1a actually, what is the number of steps on your screw LiohAu
10:45 robotust1a per 1 cm
10:45 LiohAu don't know, I know the pitch size, 20mm
10:45 LiohAu so 5
10:45 LiohAu :D
10:45 robotust1a what screw do you use?
10:45 LiohAu robotust1a: this is not the motor of the screw that I'm interested in
10:45 LiohAu it's the other one
10:45 LiohAu the one that rotate all the square plate
10:46 LiohAu so wether it is a screw or potatoes on this plate, that should not change the result :P
10:46 LiohAu robotust1a: basically what i'm trying to achieve is something like that : http://makerarm.com
10:48 LiohAu For the screw, I already know that i need around 0.09 Nm to lift the 2kg
10:48 LiohAu (this calculator told me : http://www.racointernational.com/screw_formula.htm )
10:48 robotust1a ok,what is the maximal angle speed of your robot and what is the max angular acceleration?
10:49 LiohAu 180°/1sec
10:49 robotust1a with what radius?
10:49 LiohAu 180 :)
10:49 robotust1a radius
10:49 robotust1a 70 cm?
10:50 LiohAu radius of what?
10:50 LiohAu the arm length is 70°
10:50 LiohAu 70cm*
10:51 robotust1a so you want your robot to turn 180 degree in 1 sec with the arm at full length of 70 cm with the weight 2 kg at the end?
10:51 LiohAu yes
10:51 LiohAu i'm not trying to make something as evolved as they made in the makerarm, they have 4 DoF, I only want 2
10:51 robotust1a are you building killer robot?
10:51 LiohAu So the arm is always 70cm long
10:51 LiohAu nope :D
10:51 robotust1a you need big torque
10:51 LiohAu it's just that I want to make it powerfull !!
10:52 robotust1a it will kill you one day
10:52 robotust1a so the equation is simple
10:52 LiohAu that's what they said in terminator
10:53 LiohAu is it Force (m * g) * Distance so 2kg * 9.81 * 0.7 ?
10:54 robotust1a no
10:54 LiohAu maybe should I consider centrifugal or inertia force too?
10:54 robotust1a you calculated the momentum which acts on your rail
10:55 robotust1a you can omit them for estimation
10:56 robotust1a https://upload.wikimedia.org/wikipedia/commons/0/09/Torque_animation.gif
10:56 LiohAu "r" is the red arrow right?
10:56 LiohAu oh there are colors...
10:56 LiohAu sorry ^^
10:56 Tom_itx you know 2016 will print 3d?
10:56 robotust1a yes
10:57 robotust1a LiohAu: red is radius
10:57 LiohAu yes understood :)
10:57 robotust1a but for instance in your case you'll accelerate from 0 to 90 degree and break down from 90 to 180
10:58 robotust1a it's your minimal torque you apply
10:58 LiohAu is it related to the trapezoidal/square sinus law?
10:58 robotust1a I don't know such law
10:59 LiohAu read something about 1/3 1/3 1/3, the 1st being used for acceleration, the 2nd for constant speed, and the 3rd for decelleration
10:59 LiohAu robotust1a: http://machinedesign.com/motorsdrives/how-pick-motors-linear-motion => "Move profile = 1/3-1/3-1/3 trapezoid–controlled acceleration and deceleration"
10:59 robotust1a so you task is - turn with constant acceleration from 0 to 90 to reach it in 0.5 second
11:00 robotust1a you need to find this acceleration from kinematic task
11:01 robotust1a [Angle] = ([Ang_acc] * t^2) / 2
11:02 robotust1a [Ang_acc] = Sqrt (2* [Angle] / t^2)
11:02 robotust1a [Angle] = 3.14/2,
11:02 robotust1a t = 0.5s
11:03 robotust1a calculate
11:03 robotust1a you find your acceleration
11:03 LiohAu so ang_acc is in rad/sec ?
11:03 LiohAu (since angle is in rad as I see you use 3.14/2 instead of 180) ?
11:03 robotust1a after that we find the inertion of your arm, which is [Mass] * [Radius]^2
11:04 robotust1a yes
11:04 robotust1a yes of cause
11:04 robotust1a forget about degrees
11:04 robotust1a all calculations are in radians
11:05 LiohAu so Ang_acc = sqrt(2*(pi/2) / (0.5^2)) = 3.5449
11:06 robotust1a 2 kg * 0.7 *0.7 = 0.49 * 2 = 0.98 kg*m^2
11:07 LiohAu 0.98 it's the inertia of the arm, right?
11:07 robotust1a yes
11:07 LiohAu and I guess it's a lot?
11:07 robotust1a yes
11:07 LiohAu since you said that I want to kill with the arm :P
11:08 Snert but you can accelerate and decelerate under control.
11:08 robotust1a and now your momentum will be your acceleration * you inercia
11:09 robotust1a 3.5449 * 0.98 ---- in Newtons * meter
11:10 robotust1a about 3.5 N*m
11:10 LiohAu so I need to find a motor that can handle 3.5 N*m ?
11:10 robotust1a yes
11:10 LiohAu wow
11:10 LiohAu ok, I think i'll reduce the speed :P
11:10 Tom_itx harmonic drive
11:11 robotust1a I told you from the very begining
11:11 LiohAu and we did not consider the weight of the arm itself :D
11:12 robotust1a yes
11:13 robotust1a I would reduce speed 2 times
11:13 LiohAu robotust1a: in the formula for the [Ang_acc] is there a "2" somewhere that refers to the [Mass] ?
11:13 robotust1a 4 times sorry
11:13 robotust1a no
11:13 robotust1a which equation
11:13 LiohAu so the angular acceleration does not depends on the mass of what is being accelerated oO
11:13 robotust1a sorry
11:14 LiohAu this one : [Ang_acc] = Sqrt (2* [Angle] / t^2)
11:14 robotust1a in the first equation there is no mass because it's kinematic equation
11:14 robotust1a 2 appears because of integration of angular acceleration by time
11:16 LiohAu well that sounds weird that the parameter that makes the required torque so high, does not depends on the mass
11:16 robotust1a no,
11:16 robotust1a it's not wierd
11:16 robotust1a it's a physics
11:17 robotust1a acceleration - is the rate at which you should turn to get the final point in time
11:17 robotust1a acceleration does not depend on mass
11:18 robotust1a and only when we need to evaluate momentum - we need mass
11:18 robotust1a because if you take 1 gramm you'll need one torque
11:18 robotust1a 5 gramms - another torque
11:18 robotust1a 1 kg another and so on
11:19 robotust1a acceleration could be the same
11:20 LiohAu thanks for the explanation
11:20 LiohAu (trying to follow the Walter Lewin lessons on youtube :D)
11:20 robotust1a for nothing
11:22 robotust1a if you know what is the task with unifom acceleration in linear motion - you should understand from where you get 1/2
11:28 LiohAu robotust1a: given the leadscrew is a really powerful reducer, if I move the motor (the one for which we just calculated the torque) onto the arm, instead of having it under the arm, I would get 5-10cm less as radius right?
11:29 LiohAu so 2 * 0.6 * 0.6 = 0.72 * 3.5549 = 2,56 Nm
11:31 robotust1a I'm away, be later
12:34 robotust1a LiohAu: I did wrong calculation
12:34 robotust1a [Ang_acc] = 2* [Angle] / t^2
12:34 robotust1a is correct
12:35 robotust1a it means that torque will be 3.5 times bigger
12:35 robotust1a for initial condition
12:38 robotust1a so the result for 90 degree in 0.5s for 2kg load at 0.7 m arm is 12.25 N*m
12:51 robotust1a Tom_itx: the link you gave is interesting but a lot of images are missing
16:50 Tom_itx robotust1a, yes i know... it'a a rather old site
16:50 robotust1a I bet it was you on the photo
16:51 robotust1a 15 years ago
16:51 Tom_itx no that's not my stuff
16:51 Tom_itx i wish it were
16:51 Tom_itx check all his machine shop tools
16:52 robotust1a there?
16:52 Tom_itx yes it's there
16:54 Tom_itx links seem broke now
16:56 adam789654123 hello
16:56 robotust1a hi
16:56 adam789654123 long time no see
16:56 adam789654123 how have you been?
16:57 robotust1a good
16:57 adam789654123 great
16:57 adam789654123 im glad to hear it
16:57 robotust1a working a little bit
16:57 adam789654123 money work or hobby work?
16:57 adam789654123 or if lucky, both!
16:58 robotust1a both
16:58 adam789654123 ahh..... then youve hit the big time
16:58 adam789654123 :D
16:58 adam789654123 imo
16:58 adam789654123 are you still working on the robot?
16:59 adam789654123 you were working on the head last i remember
16:59 robotust1a and will be working the nearest n years
16:59 adam789654123 haha
16:59 adam789654123 cool
16:59 adam789654123 im looking forward to studying some classical mechanics
16:59 adam789654123 i think thats my entry into robotics
16:59 adam789654123 or into more advanced stuff
17:00 robotust1a classical mechanics is good
17:00 adam789654123 i figure i can use my current programming skills and dive into electronics without a problem
17:00 adam789654123 but classical mechanics requires special attention for me
17:01 adam789654123 i would also be interested in integrating chemitry and robotics
17:01 adam789654123 *chemistry*
17:02 adam789654123 for example, perhaps implementing transducers that can trigger robotic events
17:02 adam789654123 that would be fascinating to me
17:03 robotust1a my plan is simple
17:04 adam789654123 mine is too, but we probably diverge in our simplicity
17:04 robotust1a just do this http://i.imgur.com/xZEKXIT.png
17:04 adam789654123 im on the terminal
17:04 adam789654123 no images
17:04 adam789654123 sorry
17:04 adam789654123 :)
17:04 robotust1a it't your lack
17:04 adam789654123 yeah
17:04 robotust1a don't be sorry
17:04 adam789654123 im not
17:04 adam789654123 :P
17:04 adam789654123 my idea has to do more with robotic compontents
17:05 adam789654123 i always mispell component
17:05 adam789654123 :/
17:06 adam789654123 can you describe robotust1a ?
17:06 robotust1a describe what?
17:06 adam789654123 how your plan is simple
17:07 robotust1a I gave you a link to my sketch of robot :)
17:07 adam789654123 XD
17:07 adam789654123 ok
17:07 adam789654123 ill save it and take a look in a windowing system later
17:07 adam789654123 :D
17:07 robotust1a but if you are in terminal - sorry, too long to desctibe
17:07 robotust1a startx
17:08 adam789654123 nice call, but i dont even have X installed yet
17:08 adam789654123 and ive been too busy (or distracted) to play with it
17:08 adam789654123 ive started working on something, which led to another thing, which led to.....
17:08 adam789654123 you get the idea
17:08 adam789654123 anyway, i feel more compelled to work on this stuff than install X
17:10 robotust1a so, do it NOW!
17:10 robotust1a DO SOMETHING
17:11 adam789654123 you need not worry about that
17:11 adam789654123 ;)
17:11 adam789654123 i have a number of ideas that can all integrate with one another
17:11 adam789654123 for some of which i have basic prototypes that i want to improve
17:13 robotust1a I spent like 10 years before I combined all my ideas
17:14 adam789654123 yeah... everything seems to be a work in progress
17:14 adam789654123 for me
17:14 adam789654123 no master plan, but defininly lots of plans
17:33 LiohAu robotust1a: well you greatly simplified the formula
17:33 LiohAu you said 1/2 * m * r^2
17:34 LiohAu but 1/2 means the arm is a full plain cylinder of radius "r"
17:38 LiohAu in my case, the arm will probably be a kind vertical 40cm cylinder of diameter 10cm (the base of the arm containing the screw, rail + TZ motor), but the arm would be a 70cm long horizontal tube (perpendicular to the base of the arm) with a small diameter (+/- 10cm).
17:38 LiohAu +of
17:42 robotust1a no
17:42 robotust1a I told you about angular acceleration
17:43 robotust1a but for inercia you need yo use M*R^2
17:43 robotust1a no 1/2 there
17:43 robotust1a I = M*R^2
17:44 robotust1a for point mass of M on the radius R from axis of rotation
17:47 LiohAu robotust1a: sorry I misread a tutorial
17:47 LiohAu http://www.engineeringtoolbox.com/moment-inertia-torque-d_913.html
17:47 LiohAu there are moments of inertia of different bodies
17:48 LiohAu (I mean there are formulas, to obtain them)
17:48 robotust1a do you know how to integrate?
17:48 LiohAu I knew :)
17:49 robotust1a when?
17:49 LiohAu 2004 :P
17:49 robotust1a why I still remember how to integrate?
17:49 LiohAu because you didn't go in a stupid school like me
17:49 LiohAu that do not make any mathematics
17:51 robotust1a church school?
17:51 LiohAu I remember derivative stuff, x^2 => 2^x, x^n => nx^n-1
17:51 robotust1a school of prists?
17:52 LiohAu No I just was fan of mathematics, physics.. and I got 3 fucking professors that disgusted me
17:53 LiohAu so after that I took the only school that was focusing on software development without anything else.
17:53 robotust1a bad luck
17:53 robotust1a software without math is an urban legend
17:53 LiohAu well not really
17:53 robotust1a does not exist
17:54 LiohAu I would say that more than 95% of the websites, mobile applications, desktop applications requires only development skills
17:54 LiohAu and maybe knowing the + - / * operators :)
17:55 LiohAu (actually % is the most used ^^)
17:56 LiohAu maths are required in specific domains, like robotics :(
17:56 robotust1a programming of UI is not a programming at all
17:57 robotust1a it's called design
17:57 LiohAu well there are designers
17:57 LiohAu and there are backend developers
17:57 LiohAu and most of the backend stuff is really "easy".
17:58 LiohAu think about an e-commerce website, there's nothing more complicated than the discount and stocks modules...
17:58 LiohAu so as I said, basic operations (+ - / * %)
17:59 LiohAu well web/mobile applications can be seen as "easy stuff", but think about linux kernel development for instance, no maths too.
18:00 LiohAu really depends on the thing you're working on.
18:01 LiohAu and you said "UI" does not count, but maths are used for 3D UI things :)
20:37 anonnumberanon hi
20:37 robopal hi
20:37 rue_shop3 robotust1a, did you see my arms playing back motion files?
20:37 Jak_o_Shadows yo
20:38 anonnumberanon https://u.teknik.io/QU1oMu.ogg
20:38 anonnumberanon it kicks
20:38 rue_shop3 https://www.youtube.com/watch?v=3N7DNfg4p9I
20:39 rue_shop3 your video just comes up black, can you put it on youtube or soemthing?
20:41 robotust1a rue_shop3: is it yours?
20:41 rue_shop3 they are
20:41 rue_shop3 they use that software I posted yesterday
20:42 robotust1a shaky
20:42 rue_shop3 yea, I found some improvements
20:42 rue_shop3 but some of it is just mechanics,
20:42 rue_shop3 on any given day I wouldn't use hobby servos, but I wanted to just bang off some quick arms
20:42 rue_shop3 I learned a lot
20:43 rue_shop3 I learn a lot on these 'goofing off' projects
20:43 Jak_o_Shadows Hmm, I wonder how robot arm IK goes with really extreme joint limits
20:45 anonnumberanon right click on the screen and "save video" or something: https://u.teknik.io/uVcgO4.webm
20:45 rue_shop3 its not in a format my player can do
20:46 rue_shop3 if its posted on soemthing like youtube, then the format is automatically normalized for anyone to view
20:46 anonnumberanon what format CAN you watch?
20:47 anonnumberanon I
20:47 anonnumberanon 'm not posting to Youtube yet.
20:48 robotust1a anonnumberanon: because of paranoia?
20:48 robotust1a don't be shy, post on youtube
20:49 robotust1a I can watch any youtube format
20:49 Jak_o_Shadows make it an unlistedvideo?
20:50 anonnumberanon It's pretty sad if you can't watch webm or ogg in 2015, you must have some pretty freedumb type of software.
20:50 anonnumberanon Anyway my video posting allocated time is over.
20:51 robotust1a anonnumberanon: give him mp4
20:51 robotust1a or avi
20:53 rue_shop3 did you know that windows media players past even xp cannot read the avi's from windows 3.1?
20:54 anonnumberanon Windows is cancer.
20:54 robotust1a in 1976 there were no any video formats yet
20:54 robotust1a anonnumberanon: no, android is canser, windows is a multitasking screensaver
20:55 rue_shop3 anyhow, those are some arms using playback software
20:55 rue_shop3 I didn't do a video of the real time tracker
20:56 Jak_o_Shadows I'm going to make a script that takes frames & puts them side by side
20:57 robotust1a anonnumberanon: what distro do you use
21:12 anonnumberanon robotust1a, Debian Jessie Xfce and Windows 7
21:12 anonnumberanon u?
21:13 anonnumberanon ah i don't have Jessie on the desktop yet because Linux is so good at imploding on itself during distro upgrades
21:13 robotust1a same, no choise, and xp in virtual machine
21:13 robotust1a but I use KDE
21:13 anonnumberanon i took the risk on the laptop and webserver, server worked and laptop was unbootable afterwards
21:14 robotust1a I bougt laptop with win8
21:14 anonnumberanon i think Debian is your best bet for a user friendly linux
21:14 robotust1a got something infected it and removed completely and installed debian
21:14 anonnumberanon i double boot Windows 7 and Debian Jessie on the laptop
21:15 anonnumberanon heh
21:15 Tom_itx no issues with the dual boot?
21:15 robotust1a I used to install many systems on PCs
21:15 anonnumberanon no issues no
21:15 Tom_itx i tried that once and it screwed up the install
21:15 anonnumberanon i double boot on laptop and desktop
21:15 robotust1a but now, I prefer to run windows in virtualbox only
21:16 robotust1a I have linux on 4 computers of 6 at home
21:16 anonnumberanon Tom_itx, what distro were you trying to install?
21:16 robotust1a so I don't care about type of OS if it works stable
21:17 Tom_itx i have it on 2 and win on the other 10
21:17 robotust1a so win 7 is stable enough
21:17 Tom_itx sometimes 3 depending
21:17 robotust1a win 10 watch your ass and report to NSA
21:17 Tom_itx don't run win 10
21:18 robotust1a about your shit
21:18 Tom_itx i use xp and 7 on mine 8 on a few others
21:18 robotust1a 7 and 8 reports also
21:19 anonnumberanon so i found how to not use the arduino libraries but still need wire.h, apparently it's not slow according to the fact i watched a guy do away with everything arduino but wire.h, and that guy knows what he's doing
21:19 anonnumberanon not sure about SPI.h either...
21:19 robotust1a what is wire.h?
21:20 anonnumberanon it's for serial
21:20 anonnumberanon nevermind
21:20 anonnumberanon it's for I2C
21:20 anonnumberanon i forget
21:21 anonnumberanon okay SPI.h is for serial and wire.h for I2C, this is my final answer!
21:21 robotust1a did you ever use i2c interface?
21:22 anonnumberanon yeah I had to communicate with an accelerometer
21:24 robotust1a I don't like i2c
21:24 anonnumberanon okay arduino just doesn't use a library it calls serial() something something and then serial just happens
21:25 robotust1a most probably because serial is built in bootloader?
21:26 anonnumberanon in that video i make the leg move with a joystick over wireless :)
21:27 robotust1a where is your video?
21:28 anonnumberanon the one I linked you didn't download?
21:28 robotust1a 404 Not Found
21:29 anonnumberanon yeah i deleted the first one, try the second one https://u.teknik.io/uVcgO4.webm
21:31 robotust1a works, but the robot is not so rigid
21:32 robotust1a or you want it to be not rigid?
21:32 Jak_o_Shadows I use centOS for the server, but windows for all the desktops. Just easier.
21:51 rue_shop3 ok , the power supply drops from 12V to 6V at 0.08A
21:51 rue_shop3 and to 2V at 2A
21:52 robotust1a your made PS?
21:52 rue_shop3 making
21:52 rue_shop3 testing output filter
21:52 robotust1a bad performance
21:52 rue_shop3 the first is an input impedence of 75 ohms
21:52 rue_shop3 this is not with the regultor
21:52 rue_shop3 its the power stage open loop
21:53 rue_shop3 second is 5 ohms
21:53 rue_shop3 hmm
21:53 rue_shop3 I need to know what the ripple is at 5A
21:54 rue_shop3 the bulk supply I'm using cant take it
21:54 rue_shop3 my other supply can take 1A, and will put out 30V
21:54 rue_shop3 the converter is running at 50%
21:54 rue_shop3 so I can only go up to about 2A with it
21:55 rue_shop3 so I need a 3A supply atleast
21:55 rue_shop3 ah
21:55 e_shop3 picks up a 12V battery from beside
21:55 e_shop3 th
21:55 rue_shop3 50%, technically 6V, so 5A
21:56 rue_shop3 Wattage is: 30.000000
21:56 rue_shop3 Current is: 5.000000
21:56 rue_shop3 Voltage is: 6.000000
21:56 rue_shop3 Resistance is : 1.200000
21:56 rue_shop3 1.2R
21:56 rue_shop3 hmm
22:02 e_shop3 throws the fet driver in the gar
22:02 rue_shop3 NEXT!
22:03 robotust1a IRF3305
22:04 robotust1a 3205
22:04 robotust1a http://www.irf.com/product-info/datasheets/data/irf3205.pdf
22:21 rue_shop3 I tried to get away with driving the fet at 5V, its not gonna work
22:22 rue_shop3 P channel IRF4905
22:22 rue_shop3 an N channel would push drive signal into the output
22:23 rue_shop3 so I have to redo my fet driver,
22:23 rue_shop3 man I hate high side fet drivers
22:23 rue_shop3 high side AND 250Khz
22:28 rue_shop3 I wonder if I can make a class A driven bipolar totem pole driver that can do it
22:35 anonnumberanon robotust1a, sorry was on a ;long phone call, yes it is only one servo here moving. I wanted to move the leg. The load is a lot on that servo right now since the leg is so heavy so it will be better when all the servos cooperate to make a kick.
22:54 rue_shop3 ok , judging by the way my fingers were almost instantly burned when I put the 1ohm load across the output, I beleive there has been an improvement
22:59 rue_shop3 ok, first stage filter .6V ripple at 4.5A, that wont cause the 2nd stage filter any problems