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.

Question 5DOF, yaw and surge platform design

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by Hocky, Nov 27, 2018.

  1. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    I am in the design phase of a 5DOF racing simulator.
    The idea is a 5DOF rig with a 3DOF design as a base, D-Box style with 4 actuators as legs.

    One option for making a compact design is making a yaw and surge platform that is controlled with 2 linear actuators pushing on each side of a pivot point.
    When both actuators is activated in parallell its surge and when they are in opposite direction its yaw.
    Example in the attached drawing.

    I have tried to get into Simtools documentation to find if and how to accomplish this.
    6 actuators in total, 4 legs and 2 for yaw, surge.
    Thanos AMC-MDBOX is the controller.

    Is this possible and what would the settings be like?
    Anyone have similar experiences or any ideas?

    (I did a more complex design at first, then I did notice a discussion on the D-Box group on FB with this idea (not there anymore?)).

    Attached Files:

    Last edited: Nov 27, 2018
  2. Thanos

    Thanos Active Member

    Joined:
    Jul 6, 2017
    Messages:
    256
    Location:
    United States
    Balance:
    1,648Coins
    Ratings:
    +279 / 4 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, AC motor, Joyrider, Motion platform, 6DOF
    Interesting idea, but I don't think it will work as intended... You are missing lots of support and guide points that are needed for such combined function. See a design below (slapped together in 10 mins....) that shows combined sway and traction loss. As you may notice, the base is free to rotate and slide, but held in place in three points from which one is a linear guide...

    traction loss.jpg
  3. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    Hi Thanos,

    Thanks for your input, I hope production of the controller is going as planned!

    I know the linear guide that has to be in the design, no problem there, its in the design but not in the professional powerpoint drawing :)

    Have not tried it in 3D yet. Maybe I could skip the linear guide if I put the actuators in an angle in or out. Would make some minor unwanted movements probably.

    I did have more problems how to design for the seat belt mounting points.
    Got a design that makes it possible to mount them on the top platform (with the legs) or on the yaw/surge platform.
    Makes the belts tighten on just the surge or surge + leg movement...what is most realistic, probably just surge?

    My initial worry is if Simtools can handle the design of the yaw/surge?

    Thanks!
    Last edited: Nov 27, 2018
  4. SeatTime

    SeatTime Well-Known Member SimTools 2.0 Beta Tester

    Joined:
    Dec 27, 2013
    Messages:
    2,034
    Location:
    Newcastle Australia
    Balance:
    25,397Coins
    Ratings:
    +2,344 / 20 / -0
    My Motion Simulator:
    DC motor, Motion platform, 6DOF
    Like Thanos, not quite understanding how this is going to work, but have you considered a DBox setup and a simple G-Seat? I've had a sim with surge/traction loss tables and a G seat is much better. Add a harness tensioner and you have most forces covered.
    Last edited: Nov 27, 2018
  5. Thanos

    Thanos Active Member

    Joined:
    Jul 6, 2017
    Messages:
    256
    Location:
    United States
    Balance:
    1,648Coins
    Ratings:
    +279 / 4 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, AC motor, Joyrider, Motion platform, 6DOF

    Try 3D design, one that has some physics if possible so you can move the objects and visually see the issues and what you need to do to get proper motion.

    I'd suggest against using belts, especially attached on servos... These beasts can produce too much force that can be dangerous for seatbelt application (broken ribs etc...).

    Simtools can mix any axis or motion cue type. with proper mixing axis you can achieve correct motion cues for any type platform.
  6. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    Have not considered that combination, thought I have gone thru every combination there is :)
    I have descided for a 5DOF, parts are ordered to.

    Thanks for your input!
  7. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    This is one of the ideas for linear motion control.
    This design I know from building car racing rear suspensions, a Watt linkage.
    Should be rather simple, stable and cheap.

    Could also be done with a linear guide bearing, some simple other guide...

    Regarding the seat belts I need to make shure there are some springs, rubber band or something that takes care of the ribs, before breaking them :)

    (is there a way in Fusion 360 to do a motion study export to movie?)

    Attached Files:

    • 1.PNG
      1.PNG
      File size:
      49.6 KB
      Views:
      14
    • 2.PNG
      2.PNG
      File size:
      49.8 KB
      Views:
      15
    • 3.PNG
      3.PNG
      File size:
      56.6 KB
      Views:
      17
    • 4.PNG
      4.PNG
      File size:
      55.2 KB
      Views:
      16
    • 5.PNG
      5.PNG
      File size:
      62.9 KB
      Views:
      16
    Last edited: Nov 28, 2018
  8. SeatTime

    SeatTime Well-Known Member SimTools 2.0 Beta Tester

    Joined:
    Dec 27, 2013
    Messages:
    2,034
    Location:
    Newcastle Australia
    Balance:
    25,397Coins
    Ratings:
    +2,344 / 20 / -0
    My Motion Simulator:
    DC motor, Motion platform, 6DOF
    That's OK, just trying to save you some time/money. You can do it later.
  9. dododge

    dododge New Member Gold Contributor

    Joined:
    Mar 8, 2015
    Messages:
    27
    Balance:
    288Coins
    Ratings:
    +15 / 0 / -0
    Just as a data point: Next Level Racing has a new commercial system using this sort of approach, though they've put the actuators the other way around so that they produce sway instead of surge, and can also do traction loss:



    It looks like they have a rigid base with linear actuators moving in fixed channels, and then at a guess the platform might attach to the actuators with a bearing in the front and some sort of slot in the back?
  10. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    That looks like a similar design but made for sway as you stated!

    I was going for a 6DOF first but budget was limiting out one actuator.
    Would be nice having the design supporting the last sway and add the actuator later if needed?
    AMC and servo drivers support more actuators so no problem there...

    Reason for going with surge was to get a clear movement for braking, gear shifts and belt stretch.
    Really no experience of sway vs surge so it is just what I imagine.
  11. Thanos

    Thanos Active Member

    Joined:
    Jul 6, 2017
    Messages:
    256
    Location:
    United States
    Balance:
    1,648Coins
    Ratings:
    +279 / 4 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, AC motor, Joyrider, Motion platform, 6DOF
    I really don't think that would be possible to have both surge and traction loss, you will face lots of technical challenges to make it work.

    Sway and Traction Loss, yes, as you can see in the video, it does exactly what I presented above in the simplified design I made with the two actuators push both front and back of the platform, in unity to create sway, and the back alone for traction loss.

    For Surge, perhaps you would need another "layer" that will move the whole platform front-back. I say layers because that's what you essentially need for this:

    Top layer: 4DOF actuators mounted vertically for Heave - Pitch- Roll.
    Middle layer: 2DOF actuators mounted horizontally for Sway - Yaw (Traction loss)
    Lower layer: 1 actuator mounted horizontaly for Surge.
  12. SeatTime

    SeatTime Well-Known Member SimTools 2.0 Beta Tester

    Joined:
    Dec 27, 2013
    Messages:
    2,034
    Location:
    Newcastle Australia
    Balance:
    25,397Coins
    Ratings:
    +2,344 / 20 / -0
    My Motion Simulator:
    DC motor, Motion platform, 6DOF
    Yep, been there done that ..Mine had a Seat Mover top layer then surge table then traction loss. They have their limitations.
  13. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    Can you tell me more about the limitations that you discovered?
  14. SeatTime

    SeatTime Well-Known Member SimTools 2.0 Beta Tester

    Joined:
    Dec 27, 2013
    Messages:
    2,034
    Location:
    Newcastle Australia
    Balance:
    25,397Coins
    Ratings:
    +2,344 / 20 / -0
    My Motion Simulator:
    DC motor, Motion platform, 6DOF
    Sure, as with most motion systems in attempting to simulate forces Ie. Surge, sway and heave, there is the initial movement which then abruptly stops even though the force data is continuing and then it has to somehow move back to centre before the next event without you feeling it which is difficult to do well even with the Simtools washout. Also with all these 'Layers' and large movements the weight you are moving increases so inertial becomes a issue and effects the motor power requirements/response and ability to accurately track the force data. A well designed G system does not have any of these issues/limitations as it just applies pressure to the body and has very little weight/inertia and no need for washout. In my sim the 6DOF is mainly used for Roll and Pitch + heave and helping with other short/small force movements (sway/surge) while the G systems look after the forces (heave/sway/surge) both long and short events. Hope that explanation helps. Not saying that the motion systems for simulating long forces are useless, but as explained above, they do have limitations that you should be aware of. Note, I use to use pitch/roll to help simulate Surge/Sway using gravity, but found that it affects real Pitch/Roll as it is in opposition and my inner ear can sense the unrealistic rotation. Really noticeable in aircraft/roller coasters where you often have large Pitch/Roll and high forces.
    • Agree Agree x 1
    Last edited: Nov 28, 2018
  15. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    Really interesting reading, opens upp some more dimensions to it!
    I guess a G-Seat would be the next step diving into and look more into.

    I was planing to make the belt retraction system handle this is some way.
    Really dont know the best way to implement this retraction for the different motions/dimensions.
    Will have to look more into this to.

    Interesting to read about the sway vs pitch/roll conflict. Is that why some rigs are done traction loss and sway and not traction loss and surge?
    As I wrote above, I assumed that the surge with the brake/acc/shifting forces is the most important for a racing rig but maybe thats more complex than this.

    Thanks for your input!
  16. Hocky

    Hocky New Member

    Joined:
    Aug 30, 2018
    Messages:
    8
    Balance:
    47Coins
    Ratings:
    +0 / 0 / -0
    Whats the pros/cons if you compare traction loss + sway vs tracion loss + surge?

    Traction loss and surge would give you the break/acc motions, gear shifts and also makes it possible to get some belt retraction to.