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Propellor for a welder — Parallax Forums

Propellor for a welder

kuekue Posts: 16
edited 2012-02-16 15:30 in Propeller 1
hi,
I am a looking for the solution to controlling three motors, about 90kg is the max load but I haven't picked the linear actuators yet. I might even build my own yet. any extra tip on what motors to buy , i'll consider.
I have gone ahead and bought a gadget gangster prop platform , as dual core/multi core seems the answer.

How can I test/read the travel on an actuator? I gather is a pot that multi turns, travel willm be about 400mm but how do I fix it up on the arm/motor please. It will be read in a C# serial program. It the actual mechanical attaching then reading I am confusedm about.
Am building a motion control platform for a flight sim with nX-Plane and FSX.

thx for any tips.

I bought microcontroller kick start book.

Q.

Comments

  • FORDFORD Posts: 221
    edited 2012-02-13 13:25
    You could fit a rotary encoder to the drive motors as well and count the pulses to know your exact potion.

    I imagine Digi-Key would have shaft encoders.

    They come in varying numbers of pulses per rotation.

    cheers,
    Chris
  • kuekue Posts: 16
    edited 2012-02-13 13:43
    ok. thx ill check out similar ones in Australia.
  • pedwardpedward Posts: 1,642
    edited 2012-02-13 13:59
    Standard industrial components use a differential encoder for tracking movement. Encoders come in 2 flavors, linear and rotary. Linear encoders are typically used on DRO systems on manual machines. They translate a linear movement into a series of relative pulses. Rotary encoders go on a motor shaft and translate rotary motion into pulses. Both are available in different resolutions.

    Before you attack this project, you should become familiar with these types of components. I would recommend CNC-Zone or the Home Shop Machinist forums. The first is geared towards these types of projects.
  • FORDFORD Posts: 221
    edited 2012-02-14 05:38
    kue wrote: »
    ok. thx ill check out similar ones in Australia.

    if i had known you were an aussie i would have said rs components here in perth.

    www.rs-australia.com.au

    cheers (from Bunbury wa)
  • Graham StablerGraham Stabler Posts: 2,510
    edited 2012-02-14 05:48
    If you use stepper motors then the travel is defined by the number of steps you have moved from some reference such as a home switch. They are easy to control, cheap and more than fast enough for many applications, might be worth considering

    I would probably avoid using potentiometers for feedback to a servo though it is possible using multi turn pots and cable drives.

    Graham
  • jmgjmg Posts: 15,183
    edited 2012-02-14 15:57
    kue wrote: »
    hi
    How can I test/read the travel on an actuator?

    You need to decide if you must have absolute, or incremental position measurement.
    The simplest encoders are quadrature-pulse-counting ones, but they have no idea where they are at Power Up.
    Sometimes that matters :)

    Google Magnetostrictive Linear Position Transducers, for a more costly, precise absolute sense system.

    Sometimes you can make a workable system, with an incremental sensor, and two or more 'limit/index switches'.
    A system can be made more tolerant of Power Fail, by frequent non-volatile store of current location.
  • MicksterMickster Posts: 2,721
    edited 2012-02-14 16:02
    kue wrote: »
    hi,
    Am building a motion control platform for a flight sim

    Unless I'm missing something here, we're talking about multi-axis, closed-loop servo control. I don't see steppers handling this.

    JMHO

    Mickster
  • kuekue Posts: 16
    edited 2012-02-14 22:50
    THANK YOU,
    the caps were intentional, that is advice appreciated.
  • kuekue Posts: 16
    edited 2012-02-15 00:28
    Mickster wrote: »
    Unless I'm missing something here, we're talking about multi-axis, closed-loop servo control. I don't see steppers handling this.

    JMHO

    Mickster

    to try and discribe (i have to do it child like for me )

    the design is rather simple imagine two sets of curved angle iron or channel around a chair(and underneath) also weights on a pully to lesson heave force. Same for ideas on motion platform but pretty good idea how to go about it as is near the same as i had myself. with this system i 'think' the suggestions are very good.

    http://www.flickr.com/x/t/0092009/photos/76744686@N08/6879810087/
  • kuekue Posts: 16
    edited 2012-02-15 00:30
    why the moderator needs to approve my post please ? Sorry, I thought it was unusual and this would be private post :(

    it must have been the wrong image type , i thought it was a code for catching multiple images, I think I was wrong don't know what I did, html/BBcode ????

    no need to reply. thx
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-02-15 08:57
    Another option for linear position sensing is a SoftPot. I wanted to make sure you knew of the option, though I doubt they would be the best choice for this application.
  • kuekue Posts: 16
    edited 2012-02-15 22:16
    i rang a large Australian internet distributor but he could not help with the explanation I gathered to tell him from this forum. He said he needed a part n umber and model !! I cant call anyone else today its past five o'clock and others i rang went to answering machine :( I will try again tomorrow.
  • MicksterMickster Posts: 2,721
    edited 2012-02-16 02:24
    Have you considered using pneumatic cylinders or does it absolutely have to be electric motors?

    Most simulators that I have come across have been suspended on hydraulic cylinders but I am thinking that three 2"-bore pneumatic cylinders @ 80PSI should handle the 90kg.

    For position feedback, a relatively inexpensive option would be Temposonic linear transducers.

    The only unknown (for me) here is how to control the flow of air. I have used pneumatic servo-valves made by Festo in the past but they were a bit spendy.

    Directional (aka: "bang-bang") valves are affordable and I have often wondered what would happen if one were to simply PWM the current to this type of valve. The coil would be opposing the spool-centering spring so I wonder if this would result in some form of proportional flow control(?).

    I would not recommend servo pneumatics for accurate positioning but they might be well suited to a flight simulator.

    Mickster
  • kuekue Posts: 16
    edited 2012-02-16 02:37
    Mickster wrote: »
    Have you considered using pneumatic cylinders or does it absolutely have to be electric motors?

    Most simulators that I have come across have been suspended on hydraulic cylinders.

    Mickster
    good to hear, I actually bought 3 hydrolic pump thingo's off ebay awhile ago. I say thingo's as I haven't viewed them since the first week of buying them., they probably need a motor, i guess the most expensive thing. Also i did set up an organic stockfeed producer with pneumatic rams for opening and closing silos whith a control board, actually i did some welding making the levers and shutes and someone else another welder come engineer did the hard part and of course an electrician charged a fortune but itb was a big control board.

    These pneumatic rams had not a greazt deal of force, so you think i could source some ? or maybe go with the hydralics ?

    thanks.
  • MicksterMickster Posts: 2,721
    edited 2012-02-16 03:08
    2" Bore cylinders @80PSI should be good for ~110kg each. A hydraulic option might be the sort of components that they use to jack cars up and down with. They have integrated pumps and motors and run off something like 24v, I believe. Again, the problem is the proportional flow control of the oil...the valve-PWM thing is on my to-do list.

    Mickster
  • kuekue Posts: 16
    edited 2012-02-16 04:04
    Hi,
    Just thought I would show everyone the kind of construction I am aiming at !!

    http://buggies.builtforfun.co.uk/Sim/mechanical.html




    http://buggies.builtforfun.co.uk/Sim/cockpit-images.html
  • MicksterMickster Posts: 2,721
    edited 2012-02-16 08:12
    kue wrote: »
    Hi,
    Just thought I would show everyone the kind of construction I am aiming at !!

    http://buggies.builtforfun.co.uk/Sim/mechanical.html

    http://buggies.builtforfun.co.uk/Sim/mechanical.html

    Now THERE's a coincidence! I am sitting here, writing software for a new CNC Tube Bender control system, utilizing this very motion controller (Galil 2183). I've been using Galil since the mid-eighties! Now I might have to build a flight simulator :)


    http://buggies.builtforfun.co.uk/Sim/Manual-3DOF/Galil.php


    M    ickster
  • Graham StablerGraham Stabler Posts: 2,510
    edited 2012-02-16 08:27
    Mickster wrote: »
    Unless I'm missing something here, we're talking about multi-axis, closed-loop servo control. I don't see steppers handling this.

    JMHO

    Mickster

    It does not need to be closed loop it just needs to move him around under the command of a computer. Steppers can definitely do that.

    Graham
  • MicksterMickster Posts: 2,721
    edited 2012-02-16 10:10
    Graham Stabler wrote: »
    It does not need to be closed loop it just needs to move him around under the command of a computer. Steppers can definitely do that.

    Graham

    Agreed but I didn't read in to it that he just wanted to be moved around. I understood it to mean a 200LB load that would need to rapidly accelerate/decelerate to simulate sudden changes in direction.
  • BasilBasil Posts: 380
    edited 2012-02-16 10:24
    Hi Kue,

    Im a kiwi and work for an Australian company who will be able to help you with the linear actuators. Ill send you a PM with the details as I am unsure what rules there are about advertising on this forum :)

    Mods, please let me know if its ok for me to provide info on my company in public and ill repost for the benefit of all (and my company hehe)

    EDIT:

    Oh, and the linear and/or rotary encoders we can help with too :)
  • Heater.Heater. Posts: 21,230
    edited 2012-02-16 11:44
    I'm still wondering what welding has got to do with any of this.
    Looks like you would have to parallel a lot of Prop pins to do any welding with Propellers!!
  • kuekue Posts: 16
    edited 2012-02-16 14:12
    Mickster wrote: »
    Now THERE's a coincidence! I am sitting here, writing software for a new CNC Tube Bender control system, utilizing this very motion controller (Galil 2183). I've been using Galil since the mid-eighties! Now I might have to build a flight simulator :smile:


    http://buggies.builtforfun.co.uk/Sim/Manual-3DOF/Galil.php


    M    ickster
    No Mickster just help me and feel a part of it :)



    Mickster wrote: »
    Agreed but I didn't read in to it that he just wanted to be moved around. I understood it to mean a 200LB load that would need to rapidly accelerate/decelerate to simulate sudden changes in direction.
    hi Mickster, I think if a person and three monitors and the flight panel i intend is roughly 200 pounds, I believe the design of it will mean a lot less force will be needed. it wont have to move 200 pounds, well it will but it wont. I rang one company late yesterday afternoon, the actuators were too slow, yes it does need a bit of speed.


    Basil wrote: »
    Hi Kue,
    Im a kiwi and work for an Australian company who will be able to help you with the linear actuators. Ill send you a PM with the details as I am unsure what rules there are about advertising on this forum :smile:
    Mods, please let me know if its ok for me to provide info on my company in public and ill repost for the benefit of all (and my company hehe)
    EDIT:
    Oh, and the linear and/or rotary encoders we can help with too :smile:

    Thanks Basil, im replying to posts before reading but as far as you posting the company I recon u could edit your post with that as other people have recommended companies they think are good so just because you are happy to work for one shouldn't exclude you !


    Heater. wrote: »
    I'm still wondering what welding has got to do with any of this.
    Looks like you would have to parallel a lot of Prop pins to do any welding with Propellers!!

    Heater I think you meant 'what has a propeller got to do with any of this, and im not sure I just wanted one and I thought of other chips like basic stamp but thought i might need a lot of stuff including switches on the 'aircraft' dash/panel reading or sending numerous things at once but getting a propeller now is really putting the cart before the horse, prop has little to do with it i think just now anyway. possible am in wrong forum. thx for your interest anyway !


    Oh, and I updated the links for the design, I had two the same.
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-02-16 14:18
    I'm pretty sure he did mean welding, in reference to the topic/title of the thread: "Propeller for a welder"
  • Graham StablerGraham Stabler Posts: 2,510
    edited 2012-02-16 15:30
    Mickster wrote: »
    Agreed but I didn't read in to it that he just wanted to be moved around. I understood it to mean a 200LB load that would need to rapidly accelerate/decelerate to simulate sudden changes in direction.

    And steppers can do this, I am not talking about taking them out of printers but properly sized they can move heavy cnc machines around very rapidly. The simulation of accel and decel is really just tilting anyway to use gravity.

    Graham
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