1. For downloading SimTools plugins you need a Download Package. Get it with virtual coins that you receive for forum activity or Buy Download Package - We have a zero Spam tolerance so read our forum rules first.

    Buy Download Package Now!
  2. Do not try to cheat our system and do not post an unnecessary amount of useless posts only to earn credits here. We have a zero spam tolerance policy and this will cause a ban of your user account. Otherwise we wish you a pleasant stay here! Read the forum rules
  3. We have a few rules which you need to read and accept before posting anything here! Following these rules will keep the forum clean and your stay pleasant here. Do not following these rules will lead to permanent exclusion from this website: Read the forum rules.

Suggestions for D-Box Type Home Theater Simulator

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by BigPines, Nov 18, 2011.

  1. jyrki.j.koivisto

    jyrki.j.koivisto New Member

    Joined:
    Aug 30, 2010
    Messages:
    85
    Location:
    Finland
    Balance:
    182Coins
    Ratings:
    +2 / 0 / -0
    I have to disagree on the fact that Dbox actuators would be state of the art concerning it's design , most of the things in the given link was just pure advertisement jargon. Rare earth magnet motor = ordinary (probably made in China) servo motor and Vector Pulse-Width-Modulation has been used in 3-phase motor bridges for ages and it is better known as SVPWM or space vector pulse modulation, nothing extraordinary or magic about it at all. Funny how they claim that a sensorless controller would outperform one that directly measures and knows for sure the values it takes and not guess them from mathematical model. Only real reason for not to measure current is the fact that the controller can be made cheaper with the expense of performance, with washing machines I guess that would be ok, but with state of the art hardware even measuring current would not suffice. It's best to measure all 3 phase's current their voltages and also the dc-bus voltage. That's the way I'm designing my servo controller. It is going to use either dsp microcontroller from microchip or 32bit avr from Atmel, for it's output stage I plan to use Fairchild's smart power module and current is measured on all three legs with Allegro's hall current sensors. Voltages are measured on the dc-bus as well on all the tree output phases. 2 current/voltage measurement would suffice on the phases as the third can be easily calculated as Iu+Iv +Iw = 0 but that would not take into account that there are minute variations between phase windings so I'll measure them all.
  2. Mizoo

    Mizoo New Member

    Joined:
    Oct 10, 2011
    Messages:
    7
    Balance:
    0Coins
    Ratings:
    +0 / 0 / -0
    I didn't say that all these functions are usefull (and I agree with you for current sensing), but driving a brushless motor in vector space modulation is not so easy that driving a simple brushed motor as described above.

    EDIT: And, from my point of view, a space vector driver IS state of the art for motor driving, especially for torque control at low speed, but maybe because it takes me some times to get my first SVM controller working at school, many years ago :D
    Such controller has been considered for my FFB wheel.
  3. BigPines

    BigPines Member

    Joined:
    Nov 18, 2011
    Messages:
    31
    Balance:
    2Coins
    Ratings:
    +0 / 0 / -0
    Thanks but I had already read that article. It was interesting but I was not all that impressed or intimidated by it. It seemed like it was just a carefully engineered advertisement full of marketing techno-babble. Although I have not confirmed it yet, I understand they are using cheap stepper motors. Why are they so much better than what we have been talking about here? I know for a fact they are using National Instruments LabVIEW as their controller. It isn't that exotic. I found at least one other person on this very board using the same thing. I have a friend who works at a very prominent robotics company here in the US who also recommended LabVIEW. As far as the wide band response goes, I may be wrong but the way I understand it, the real motion comes from way below 100Hz anyway. This isn't anything new. Anything near 100Hz would be heard too much and felt too little. All the real motion is probably below 5Hz anyway right? Their sophisticated motion coding system is nothing more than audio tracks in an off-the-shelf video editor (Sony Vegas). Their motion samples are just wav files. I think they want people to be intimidated into thinking they are doing something so special it can't be replicated (or even improved upon). I'm not buying it yet. If I turn out to be wrong, I will abandon this project and just buy D-BOX. I know I still have some hurdles to overcome but so far everything I see points to being able to do much better than they are and maybe even save a few bucks to boot.

    This is not intended as a flame in any way. If you know something I don't, please school me. That is why I am here. :)

    Mike
  4. Mizoo

    Mizoo New Member

    Joined:
    Oct 10, 2011
    Messages:
    7
    Balance:
    0Coins
    Ratings:
    +0 / 0 / -0
    As you said, we'll see ;)
  5. adgun

    adgun Member

    Joined:
    Jan 28, 2008
    Messages:
    343
    Occupation:
    mechanic
    Location:
    Netherlands
    Balance:
    4,311Coins
    Ratings:
    +64 / 3 / -0
    Every one knows that integrated actuators are easier for diy.
    But i think it,s better to buy 4 dyadic rsa1211 servo motors from www.miraiintertech.com and make you,re own actuators
    than buy 40 scn5 actuators ,to get the needed force
  6. BigPines

    BigPines Member

    Joined:
    Nov 18, 2011
    Messages:
    31
    Balance:
    2Coins
    Ratings:
    +0 / 0 / -0
    Any thoughts on using roller screws vs ball screws?

    http://www.nookindustries.com/RollerScr ... bility.cfm

    I know they are more expensive, should handle more weight and last longer. Any other benefits or downsides?

    Mike

    Edit: Meh, looks like they are better but just too much money.
  7. adgun

    adgun Member

    Joined:
    Jan 28, 2008
    Messages:
    343
    Occupation:
    mechanic
    Location:
    Netherlands
    Balance:
    4,311Coins
    Ratings:
    +64 / 3 / -0
    5000rpm max. more sillent!
  8. LBodnar

    LBodnar New Member

    Joined:
    Nov 25, 2011
    Messages:
    2
    Balance:
    0Coins
    Ratings:
    +0 / 0 / -0
    State of the art? :no: D-Box uses standard Danaher AC servo motors with part numbers removed.

    I have been demoing Parker linear actuators that I have kitted with Danaher motors to a customer who happened to have D-box in the workshop. Our jaws have collectively dropped when it turned out I had the same motor on one of the smaller Parkers.

    The Parker I have shown was 450mm stroke, 1200mm/s speed, 3000kN max load and 1.2G acceleration driven by 6kW peak (delivered to motor) servodrive on each leg.

    I have no idea about D-Box specs but the power requirements on its PSU was something like 400W for all four actuators. You can guess the rest using Newton physics and assumption that PSU+drive has probably ca. 80% efficiency.

    Not sure about actual ball-screw actuator and servo-drive but I doubt they have invented anything new there.
  9. THX-UltraII

    THX-UltraII New Member

    Joined:
    Dec 14, 2011
    Messages:
    1
    Balance:
    0Coins
    Ratings:
    +0 / 0 / -0
    Hi BigPines,

    I saw you on the AVS D-Box topic too a few weeks ago and I found this thread today. I m curious how far you will come with this project so I registered over here.

    The thing that will be the most difficult to do I think is making the actual codecs for movies. D-Box has a lot of experience in this (they did a lot of years of research and investing before they launched the first D-Box motion system) and I really wonder if it will be that simple to code a whole movie let alone a few movies per month just by yourself without the knowlegde and right software.

    Don t get me wrong, I really like what you are trying but it s just some things you need to think about.

    I own a SRP-230 and MCI-2P by the way
  10. BigPines

    BigPines Member

    Joined:
    Nov 18, 2011
    Messages:
    31
    Balance:
    2Coins
    Ratings:
    +0 / 0 / -0
    Thanks LBodnar. Very interesting information about the motors they are using. Could you by chance provide a model number of the motor?

    Hello THX-Ultrall, small world. :)

    This project is going to take a long time. I have several different aspects of this project and they are each complicated. One idea I have is to tap into the existing D-Box codes. We shall see...

    Mike
  11. wintsu

    wintsu New Member

    Joined:
    Aug 31, 2018
    Messages:
    3
    Balance:
    36Coins
    Ratings:
    +0 / 0 / -0
    Hi Mike,
    Did you already build a platform according to your specs?
    Now, 7 years after date, I am also looking for a relatively simple solution using linear (shaft) motors (basically a shaft of permanent magnets moving within a coil). See my post/question.
    Do you have any suggestions/opinion using this type of motor for a home-theatre/motion-simulator platform?