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Showroom DX - Compact Simulator

Discussion in 'DIY Motion Simulator Projects' started by noorbeast, Sep 29, 2014.

  1. SilentChill

    SilentChill Problem Maker

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    Great work @noorbeast good to see it all back together and working again.
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  2. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    Still a bit to go @SilentChill, there are new HOTAS mounts to make, the haptic harness to add, the computer dock to finish and finding a place to mount and wire in the Arduino for surge control. But at the moment work is taking precedence.
  3. -kevin-

    -kevin- Fast e Furious

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    Sim extraordinary !! from all points of view! :thumbs

    Have you ever thought about putting the loss of grip? ;)
  4. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    Yes I do have plans for a combined compact yaw/traction loss, but they are a long way off at the moment @-kevin-.
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  5. -kevin-

    -kevin- Fast e Furious

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    I imagined that you had already in mind the yaw :) would be the icing on the cake on this sim :p
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  6. Archie

    Archie Eternal tinkerer

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    @noorbeast - Time permitting, would you mind making a close up video of how that heave mechanism is working. I've watched the video a few times and also read your reply to the other member. Is the office chair mechanism the seat height adjustment part or the forward and back tilt part?

    Oddly enough, some time ago I had the same idea of using an office chair for heave where actuating the height adjustment would drop the chair, but could not figure out how to pull the chair back up as you normally have to take your weight off the chair to adjust it for more height..

    Awesome work as always Sir. Very impressive set up!
  7. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
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    The mechanism is the tilt part, I already had it but this is an example of the style I used, so it could be purchased. You would want to hunt around concerning price if there was a need to buy one: http://www.ebay.com/itm/Office-Chair-Seat-Plate-Knee-Tilt-Mechanism-Control-NEW-/380342104992

    What I really need video wise is good lighting, as I was trying to capture the heave plate mount movement in the first half of this video: http://www.xsimulator.net/community/threads/dx-racer-compact-simulator.5866/page-15#post-83683

    What I may do is try and do a video of it as a 1DOF, with the heave motor driving heave, surge and pitch. With the Rift the 1DOF surprisingly feels pretty good and while you miss the sway it is not as much as you would think!
  8. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
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    Some maintenance updates.

    I started getting frequent JRK usb disconnects on the right front motor. I swapped out the motor and usb cable, which had no effect, so I concluded the most likely cause was a failing PSU, which was indeed the problem. I use HP server DPS-600PB PSUs and managed to pick up a brand new replacement, with the genuine HP shipping box being somewhat of an overkill:

    IMG_20150911_084916.jpg

    In the past I soldered the bridge wires direct to the PSU terminals, as per @Slider's original guide: http://www.xsimulator.net/community/threads/how-to-modify-a-server-power-supply-for-12v.5774/

    However, this time I am trying something different to simplify swapping out a PSU within the very tight confines of my sim. I have pinched each pair of the blade terminals together and used two 6.3mm female connectors each side to bridge the bade terminals. I then soldered and shrunk wrapped the power cable to the wire bridge just behind one of the terminals. I don't know how well it will hold up in the long run but so far so good and it means I can easily swap out a standard PSU in minutes, without pulling the whole sim apart.

    I also noticed that some of the springy metal tabs that normally provide tension in a server PSU bay have been catching on the frame of my sim when I pull it out in an upward direction. So to ensure that can't happen and to prevent any possible chance of earth leakage I also shrunk wrapped the whole PSU before putting it back in the frame.

    IMG_20150912_112620.jpg IMG_20150912_115346.jpg IMG_20150912_120409.jpg

    While I was at it I also modified the pedal plate so that there are three different mount positions, using two quick release thumb bolts. I have a short mount position for my sister and father, a medium length mount position for myself and one for friends with long legs:

    IMG_20150912_141725.jpg IMG_20150912_141745.jpg

    I replaced the motor to gearbox coupling in the heave motor when I was swapping motors around, as I had some new metal ones to replace the original plastic items. I have also replaced the one 60:1 gearbox that I have encountered problems with. This gearbox has had two separate sets of gears in it. The second set of gears has only had really limited light use over a month but was already starting to have excessive play. The original 60:1 on the other side has been subjected to the same setup and use since I built the sim and is as good today as the new box I just added. My conclusion is that flipping the shaft may well be the real issue. Hence the new box is right handed so that is not necessary.

    Now that the pesky USB disconnects are resolved I can spend some time refining the motion profiles. I also have to make the new HOTAS mounts and tidy up the computer dock and associated control box. I just picked up some tiny chrome housed LEDs today so that I can implement @Archie's JRK disconnect warning lights and reset switches in the limited space I have on the control box.
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  9. muxximess

    muxximess New Member

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    Hi Noorbeast,

    Ive been following your thread and love your meticulous workmanship and incredibly well thought out design choices.

    One idea that I was hoping to replicate of yours was your heave spring concept with the knee tilt mechanism. One thing I was wondering if you could answer for me is how the spring maintains its tension when you sit on the chair? Is this done by turning the tension knob until it can support the desired weight?
  10. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    Yes @muxximess you just adjust the spring to suit, though near maximum works pretty well for me.

    The only downside is that I have to turn off the heave motor if I leave the sim running for a while without being in it, as the 25:1 motor can't indefinitely hold the positive upward force that is being exerted on it when unloaded. The 60:1s are unaffected, as they can hold even when un-powered.

    One day I may well swap all gearboxes to 50:1 and be done with it, as they can also hold unpowered. I would pick up a bit more speed at the front while softening the heave speed.

    What is crucial is the adapter between the heave knee and universal joint, as it is designed to minimise the front pivots through its arc.
  11. muxximess

    muxximess New Member

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    Hi @noorbeast

    Thanks so much for your quick and detailed response, I really appreciate it!

    I hope I don't sound like a complete idiot and that I've understood you correctly. From what I gather, have you set the 25:1 motor to depress your heave spring half way when it is turned on? I.e. That the half-way mark is the starting point from which your heave motion begins, so that you have room in the heave spring for upward and downward movement once the simulation starts?

    And out of curiosity, if you hypothetically sat on your seat without any motors connected to it, is your heave spring able to support your weight? I.e. can it stay elevated despite you sitting on it?

    I can see your point on the 50:1 motors, from reading this forum, they sound like an excellent compromise for staying put when unpowered, but having decent speed.

    I'm not sure if I entirely understood your last comment about minimising the front pivots through the arc. Are you referring to minimising the weight transfer through the two front motors you have by virtue of the heave spring absorbing part of the weight transfer?

    Out of curiosity, does the heave spring dampen or slow down other movements, such as roll or pitch for example, by virtue of being depressed first before the universal joint moves? Or does that not happen if the uni joint is positioned correctly on the heave spring?

    I hope I haven't bombarded you with too many questions, I'm a bit of a newbie to motion sims!

    Thanks again!
    Last edited: Sep 15, 2015
  12. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    Yes, when activated the heave motor centralizes the heave spring position and can move it up and down from there.

    I actually use my sim as an office chair unpowered, which is why I chose the 25:1 for the heave at the rear. The 60:1s at the front remain in position when unpowerd. The heave spring will support over 100kg unpowered and being adjustable will perfectly balance a users weight. The unpowerd 25:1 moves, so the seat has some 'give' under you up and down if you shift your weight, which makes it really comfortable.

    When in use the heave spring balances the users weight and provides some small positive lift force up and some small negative resistance down, both of which actually help as the user weight is already assisting downward movement anyway and the positive up helps lift the user more quickly.

    The last comment is about the arc the heave knee travels through and the relative position of the universal joint used to minimize the impact. When I mocked up the heave it was immediately obvious that seat would travel through a large arc relative to the much smaller arc of the knee if the joiner was perpendicular to the heave knee:

    1.jpg

    So the joiner is angled forward to minimise that impact, that way the seat travels through a much smaller arc comparable to the knee itself:

    IMG_20150703_135304 (600 x 450).jpg 26695-8ffb9cf9205bbc6fcbc2c4cdac6caab2.jpg 26696-aaf071f8e323b837795cf62518e29de9.jpg
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    Last edited: Sep 16, 2015
  13. muxximess

    muxximess New Member

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    Thanks @noorbeast, the theory of how to integrate the heave spring is making a lot of sense and I really appreciate your sound technical advice.

    I'm not sure if I completely have my head wrapped around your concept of the angled forward uni joint. If I built on the idea of the angled forward uni joint, would I be right in saying that you could achieve the same result if you shortened the overall height uni joint? Or have I misinterpreted the concept in the design of forward angling uni joint?
  14. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    Yes reducing the height helps and I did that in the final adapter within the restrictions of my design, which related to the seat height relative to the plate height that mounts the pedal rail.

    There is a practical limit in the height where the seat will hit the adjusting knob in the circumstance where the heave spring is depressed and the seat is in the pitch forward position.
  15. muxximess

    muxximess New Member

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    Thanks @noorbeast! It all makes sense and I can see how the adjusting knob might get in the way...

    Loving this heave spring idea. The only concern was whether the heave spring might slightly slow down the performance of the uni joint movement under pitch motion, since the heave spring will be pushed and pulled on under pitch motion. But I assume if the other two motor arms (the two outside of the heave motor) are positioned properly and the seat is positioned on the uni joint as closely to the centre of gravity as possible, the two motor arms should tilt the uni joint without placing any pressure on the heave spring, therefore making for a very clean and fast pitch motion. Would this be correct from an engineering perspective?
  16. muxximess

    muxximess New Member

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    I guess the heave motor also stiffens the heave spring, by virtue of being in control of it, therefore not allowing the heave spring to be pulled and pushed on, unless the heave motor says so. However, would that then imply that the other two motors are also in a sense fighting with the heave motor, albeit a relatively small fight since the degree of movement will be minimal?
  17. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
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    You use all three motor to control heave. So they all move down or up in unison for their heave axis settings. But in practical terms that is also affected by what is also mixed in for other axis settings and there is a very slight lateral affect because the heave knee is traveling through and arc.

    I am currently playing with motion profiles in how I mix and manage their movements with percentage allocations and filters, with the front motor responses being setup somewhat sharper for the vibration like response of harsh bumps and the rear heave being more undulation in response to bigger heave movements. Like all motion profile development the settings are somewhat unique to the game and car/track chosen. But it feels very different for say the Assetto Corsa Cobra at Nordschleife, which sort of floats around a lot compared to say the Williams F1 on the same track, as it has harsh suspension responses. In fact the Williams is a bit too harsh on the same settings, which is likely what that sort of car would be like at Nords, and is a bit too realistic with harsh heave motions on the sim to be pleasant for too long.
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    Last edited: Sep 17, 2015
  18. Nick Moxley

    Nick Moxley Well-Known Member

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    My Motion Simulator:
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    Lmk how the JRK reset box goes, Mine didn't turn out as i expected. No clue whats actually wrong, Followed Archie's wiring and im left scratching my head.
  19. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    So do you suggest it is a good idea to wire and test before I go drilling holes in my pretty alloy control box?

    I do not plan to add the reset warning and switches until the next major update where I pretty much tear the sim down again, as I have to add wires to my JRK box and run them back to the control box, but it is on my todo list of upgrades. I could do a temporary wiring test by removing the JRK fan and run the wires that way.
    Last edited: Sep 17, 2015
  20. Nick Moxley

    Nick Moxley Well-Known Member

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    I would suggest it yes.
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