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Gtwiin's 2DOF sim

Discussion in 'DIY Motion Simulator Projects' started by Gtwiin, Aug 19, 2020.

  1. Gtwiin

    Gtwiin New Member

    Joined:
    May 25, 2017
    Messages:
    25
    Occupation:
    Student
    Location:
    Madrid
    Balance:
    46Coins
    Ratings:
    +9 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    This is my 2dof sim.
    I started to build it a few years ago, although due to time issues I couldn't make it work perfectly until now.
    This is the end result after many changes and improvements, but I'll keep upgrading it and my plans are to make it a 3dof.
    Front sim.jpeg Motor detail sim.jpeg Axis detail sim.jpeg
    I'll try to explain every detail and problem I encountered in further posts!
    • Like Like x 4
  2. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    20,461
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    144,602Coins
    Ratings:
    +10,741 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    Looking forward to hearing more about your rig, the challenges you encountered and how you overcame them :thumbs
  3. Gtwiin

    Gtwiin New Member

    Joined:
    May 25, 2017
    Messages:
    25
    Occupation:
    Student
    Location:
    Madrid
    Balance:
    46Coins
    Ratings:
    +9 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    1st Post: Planning and prototyping
    In this post I will cover all the initial steps I made and why I made them that way.

    Please note that I have improved my sim since I started building it, so maybe there are some things that are different to the final state.

    I started my sim in 2017, and in that moment I wanted a sim that could simulate the most movements possible in a reliable way at a relatively low budget.
    So, I evaluated the possibilities I had there.
    First of all I had to decide how many degrees of freedom I could simulate within my budget.
    If you want to know more about the movements you can simulate I find this very useful: https://www.xsimulator.net/co-ordinate-system/
    At this point I could choose between a 2dof, a 3 dof, and a 6dof sim.
    The 6 dof one got discarded at the beguining as it was more complex and far more expensive.
    A 3 dof was a very good option but at the moment it would increase the cost and as I had no experience finally opted to make a simplier 2dof sim. In the future my plans are to make my actual 2dof sim a 3 dof sim.

    Once I chose the type of sim that I wanted to build I began modeling it and making a list of materials that I could need.
    First I made a simple model using blender
    upload_2020-8-22_12-42-24.png
    This helped me getting to the right measurements.
    As you can see I opted to integrate the pedals and steering wheel into the moving frame. You can separate them, but I wanted to mount my monitor in the moving frame and considered this was a better solution.
    To make this model I took into account some requirements that I set and some that were needed.
    First of all I wanted to make it fully adjustable and versatile, so I opted to build it using aluminum slot profiles.
    upload_2020-8-22_13-7-0.png
    As I wanted to be able to change the frame dimensions everytime I needed, I made even the central axis out of aluminum profiles.
    upload_2020-8-22_13-8-11.png
    Using this type of structure made it more expensive (only the profiles were 61.5% of the budget), but as I planned to improve the whole sim I wanted a solid base that I could modify later.
    Then I made some calculations and set a g force objective. This way I got to know every measurement of the frame needed to accomplish this objective.
    In general terms I set the center of mass over the central axis and adjusted the distance to the point where the motors apply their force. If you want I could make a more detailed post with the exact calculations and things I got into account.

    After that, when I was happy with the model, I 3d printed it. This was useful to realise some design flaws and to explain it to people.
    [​IMG]

    At this moment I had a good model to base the construction on, so I started planning the electronics part that I will cover in further posts.
    Once I had all the project planned I started doing a "shopping list" with the materials and items, and their respective costs so I could get a general overview of it and adjust some things in order to reduce the overall cost.

    In the next posts i will continue covering some of this steps so see you then!
    • Like Like x 1
  4. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    20,461
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    144,602Coins
    Ratings:
    +10,741 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    What motors and hardware have you used?
  5. Gtwiin

    Gtwiin New Member

    Joined:
    May 25, 2017
    Messages:
    25
    Occupation:
    Student
    Location:
    Madrid
    Balance:
    46Coins
    Ratings:
    +9 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    I used 2 wiper 12V motors from a Citröen Xsara, so far they work fine and have good torque. On the hardware side I used an Arduino with 2 monster motor shields, one for each motor (I had some problems with them that I'll try to explain in a further post). Right now my limiting factor is the power supply that is from a pc and has a maximum current of 25A that turns off when the motors have to work too hard, anyway this is no problem as I can avoid it with smc3.
    My plan with the power supply is to buy another one and run these two, one for each motor. Could this work fine?
  6. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    20,461
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    144,602Coins
    Ratings:
    +10,741 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    Personally I prefer a PSU per motor, as our rigs can generate some pretty big power spikes.

    LED and server PSUs are both pretty cheap and preferable options, LED PSUs are a bit more tolerant of power spikes than server PSUs.