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2 DOF step by step from 0

Discussion in 'DIY Motion Simulator Projects' started by Hector Javier Rios, Mar 28, 2019.

  1. micma80

    micma80 Member

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    di, I don't see recirculation diodes on H bridge: the mosfets you use require them ... so in addition to not doing overvoltage damage, send the energy back to the batteries and the system is more reactive (if you use power supply remember the shottcky diode on the positive between power supply and batteries),
    regards
    micma
    • Informative Informative x 1
  2. Hector Javier Rios

    Hector Javier Rios New Member

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    Mar 26, 2019
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    Location:
    Medellin, Colombia
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    366Coins
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    My Motion Simulator:
    2DOF, DC motor
    no modification is necessary, the only thing that you can not forget is to energize the electromagnetic brakes every time you use the motors and you have all the reason, no doubt these motors look much more robust than the wiper motors but for that reason they should be used much more powerful motor controllers than would normally operate wiper motor
  3. sam poole

    sam poole Active Member

    Joined:
    Nov 14, 2017
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    midlands
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    34Coins
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    +45 / 0 / -0
    My Motion Simulator:
    3DOF, DC motor, Arduino, Motion platform, 4DOF, 6DOF
    Thanks for this so I guess unlikely my mm sheilds will do the job, do you know what would be required instead? other than doubling up the mms (sorry for hijacking your thread)
  4. Hector Javier Rios

    Hector Javier Rios New Member

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    My Motion Simulator:
    2DOF, DC motor
    If you look at the data sheet of the mosfet you will notice that it has integrated clamp diodes so it is not necessary to place external protection diodes, however, thank you very much for your observation.
  5. Hector Javier Rios

    Hector Javier Rios New Member

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    Medellin, Colombia
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    My Motion Simulator:
    2DOF, DC motor
    hi @sam poole. I can not assure you if the MM shield or any other commercial driver will or will not work with the motors that I use because I have not looked at their technical characteristics, however I have noticed that when using 24v motors many people here select as controller the saber tooth. I personally do not know any of these drivers because in my country get these devices is very difficult, if you get one luckily the prices are extremely high, the best option would be to bring them from abroad. fortunately I can manufacture my own driver, maybe my driver does not have all the benefits and advantages of commercial drivers but I think they will do the job well
  6. micma80

    micma80 Member

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    Ok, tnx, look thanos h bridge om the forum,
    Micma
  7. hannibal

    hannibal Active Member

    Joined:
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    My Motion Simulator:
    6DOF
    i went crazy to figure out motor drivers... just go for sabertooth...
  8. Hector Javier Rios

    Hector Javier Rios New Member

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    Mar 26, 2019
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    Medellin, Colombia
    Balance:
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    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    I assume that saber tooth is a very good product, I only read positive comments from them and I am happy for their users. I will survive with my DIY controller
  9. hannibal

    hannibal Active Member

    Joined:
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    My Motion Simulator:
    6DOF
    all good, gotta start somewhere.. i bought the garbage MM just to see how things work...
    • Agree Agree x 1
  10. Hector Javier Rios

    Hector Javier Rios New Member

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    My Motion Simulator:
    2DOF, DC motor
    I downloaded the user manual of simtools and I have taken a look at it and it has made me very happy how well explained it is, being able to notice that it is a great software, very complete and with many adjustable parameters that will facilitate me to a large extent the realization of my control algorithm I was thinking that my control algorithm had to worry about controlling and correcting big and abrupt changes of direction (for example 000 to 255), but apparently simtools offers me several filters to correct these situations (someone tell me if I'm wrong ).
    to tell you the truth, I still do not know where to start building my control algorithm. Maybe I do not have to worry about the axis assignment tab until I have the communication ready, so I will put all my attention in the interface settings tab and I'll work in the communication between simtools and my hardware.
  11. Hector Javier Rios

    Hector Javier Rios New Member

    Joined:
    Mar 26, 2019
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    Location:
    Medellin, Colombia
    Balance:
    366Coins
    Ratings:
    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    to tell the truth I still do not have a decent pc for games, I'm thinking of a modest compilation for VR but this will be later. Meanwhile, I believe that my old laptop will be used for basic tests. I downloaded the simtools software to learn how it works, for now I made a virtual serial connection with the old but always useful hyperterminal tool and following the suggestion of the user manual I established the following:
    The user manual recommends a transfer speed of BitsPerSec 115200bauds, (someone can tell me why this speed is ideal, I think it could be much lower for 2dof) DataBits 8, Parity none, StopBits 1.
    The Output - Bit Range is set to 8 bits value with which I agree since it will give me 255 output positioning values for the motors which is more than enough for 180 degrees.
    Output - Type I have selected decimal which will give me the characters that are placed outside the symbols <> of the Interface - Output tab followed by a value between 0 and 255 for each motor.
    Output Rate I suppose that it should be adjusted to a reasonable time.
    for now I do not know if I'm going to use Startup - Output and Shutdown - Output
  12. Hector Javier Rios

    Hector Javier Rios New Member

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    Medellin, Colombia
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    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    my last acquisition a U joint robust enough and a sports chair
    silla.jpg joint.jpg
    • Like Like x 1
  13. Hector Javier Rios

    Hector Javier Rios New Member

    Joined:
    Mar 26, 2019
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    26
    Location:
    Medellin, Colombia
    Balance:
    366Coins
    Ratings:
    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    to make the communication between simtools and my microcontroller I had to buy a usb to serial converter cable (brand chipi x) and a serial to ttl converter. I have been working on my control algorithm and although I have programmed microcontrollers several times this is the first time using the PID libraries so much reading and learning awaits me.
  14. Arielnac

    Arielnac Member

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    Nov 20, 2017
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    79
    Location:
    Argentina
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    65Coins
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    +32 / 0 / -0
    My Motion Simulator:
    2DOF
    Hi. Like other users, I believe that your pulley design to link the motor shaft with the hall sensors will be out of sync during the biased steering changes of the motors. You must use toothed belt.
  15. Hector Javier Rios

    Hector Javier Rios New Member

    Joined:
    Mar 26, 2019
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    26
    Location:
    Medellin, Colombia
    Balance:
    366Coins
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    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    I have been working on my control algorithm and learning how to use the PID library of my dsPIC. the first routine I did will take care of bringing the cranks to the central position in a smooth way. I started with this simple task to check that my belt pulley mechanism worked correctly and for now it does.
  16. Hector Javier Rios

    Hector Javier Rios New Member

    Joined:
    Mar 26, 2019
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    26
    Location:
    Medellin, Colombia
    Balance:
    366Coins
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    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    Although I had never worked with the PID libraries before, I think that the code I have written is working well. for now I have only done trials with low power motors and although I am not an expert in the tuning of a PID what my logic tells me is that it is working well. my next step will be to buy a reasonably good compilation for a PC that later serves me for VR.
  17. Hector Javier Rios

    Hector Javier Rios New Member

    Joined:
    Mar 26, 2019
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    26
    Location:
    Medellin, Colombia
    Balance:
    366Coins
    Ratings:
    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    I already ensable a PC ready for VR of moderately good features and I have downloaded the SIMTOOLS software. I would like to know where I can download the LFS game to start doing some trials.
  18. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    Innovative tech specialist for NGOs
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    St Helens, Tasmania, Australia
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    144,614Coins
    Ratings:
    +10,741 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    You can download the trial version of LFS here, which works fine with the fully functional SimTools plugin: https://www.lfs.net/downloads
  19. Hector Javier Rios

    Hector Javier Rios New Member

    Joined:
    Mar 26, 2019
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    26
    Location:
    Medellin, Colombia
    Balance:
    366Coins
    Ratings:
    +12 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor
    After several months away from my project for work reasons and lack of time I want to continue it now.
    Another reason that made me leave the project was that I was having problems to debug my code and now I must redesign my control card because I need to add current and temperature sensors to protect my H bridge, I will also put a 16x2 LCD screen and taking advantage of that I have to do the whole design of the PCB again, so I want to make a design taking into account the necessary I / O ports to later add a wind simulator and something else that can be done.
    • Like Like x 2