1. Do not share user accounts! Any account that is shared by another person will be blocked and closed. This means: we will close not only the account that is shared, but also the main account of the user who uses another person's account. We have the ability to detect account sharing, so please do not try to cheat the system. This action will take place on 04/18/2023. Read all forum rules.
    Dismiss Notice
  2. 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 Now a Download Plan!
  3. 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
  4. 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. Do not follow these rules can lead to permanent exclusion from this website: Read the forum rules.
    Are you a company? Read our company rules

Simple Servo Seatbelt tension system

Discussion in 'DIY Motion Simulator Projects' started by PMK, Feb 9, 2020.

  1. PMK

    PMK Member

    Joined:
    Jun 12, 2018
    Messages:
    43
    Location:
    Australia
    Balance:
    125Coins
    Ratings:
    +8 / 0 / -0
    Hi All,

    Here's my first motion simulator project. I've been playing around with using RC servo's as a cheap way to add more tactile feedback to my simulator.

    I was able to get my hands on some MG996R servo's which have around 10kg of torque. I figured that I might be able to double up the servo's so 2 are used on each seatbelt for around 20kg of total torque on each belt.

    I'm using an old PC PSU to power the servo's with 5V and an Arduino Nano to send the control signals from SimTools.

    Here's my inital prototype mount for test fitting. (Janky but it works)
    [​IMG]
    [​IMG]
    And here's a video of the first prototype in action.
    https://drive.google.com/open?id=1eEhfkRde5Tnr1WSGAI2UOf_S9FXXtur3

    So far the feeling of the belts is great however they're pretty weak. I'll attempt a dual servo setup after I make this post however I think I may have some issues getting them lined up and synced perfectly.

    My favorite thing about this setup is that when the belts are tight, the servo's actually vibrate and move the chair slightly.

    Attached Files:

  2. PMK

    PMK Member

    Joined:
    Jun 12, 2018
    Messages:
    43
    Location:
    Australia
    Balance:
    125Coins
    Ratings:
    +8 / 0 / -0
    Managed to get the servo's aligned on both sides of the belt. Feels even better now!
    [​IMG]

    My next step is to develop a 6v regulator circuit. Currently I'm running these off the 5V rails on my PSU but I can get about an extra 1.5kg/cm of torque by using 6V. Any suggestions on the best way to go about this?

    I'm also planning to 3D print some proper mounting/alignment brackets for the servos so I can screw them in directly to the wooden beam they're currently clamped to.

    Obviously the servo's stall during heavy braking, should I worry about constantly putting the servo's into stall? Or does it not matter because it's only for short periods of time?

    Attached Files:

  3. Historiker

    Historiker Dramamine Adict Gold Contributor

    Joined:
    Dec 16, 2010
    Messages:
    2,158
    Occupation:
    Retired
    Location:
    Michigan USA
    Balance:
    9,176Coins
    Ratings:
    +2,156 / 19 / -1
    My Motion Simulator:
    3DOF, DC motor, Arduino, Motion platform, 6DOF
    Do you have pictures of the entire rig?

    Cool idea, hope it works out for you.
  4. wannabeaflyer2

    wannabeaflyer2 Well-Known Member

    Joined:
    Jun 12, 2015
    Messages:
    724
    Location:
    london uk
    Balance:
    8,286Coins
    Ratings:
    +950 / 7 / -0
    My Motion Simulator:
    2DOF, Arduino, Motion platform, 6DOF
    Hi @PMK really like the simplicity of this option but have to say i have doubts about the tension those Servos will be able provide ,, i think this method has great promise but you'll def need stronger geared motors if the system is to last more than a few minutes of heavy breaking ... windscreen wiper motors with feedback encoder / Hall sensor Pot or standard 10k Pot may be the way to go... your option has piqued my interest and you've now got me thinking about changing the fixed Bungees im using to your active tensioning method :)

    Did you just use brake pressure sensor / Switch to activate your servos , what range are you using in terms of servo angular rotation..
  5. Moe Colontonio

    Moe Colontonio Member Gold Contributor

    Joined:
    Dec 9, 2017
    Messages:
    118
    Location:
    New Jersey USA
    Balance:
    750Coins
    Ratings:
    +30 / 1 / -0
    My Motion Simulator:
    3DOF
    So for systems using wiper motors, or other motors, what do you do to account for motor stall?
  6. Historiker

    Historiker Dramamine Adict Gold Contributor

    Joined:
    Dec 16, 2010
    Messages:
    2,158
    Occupation:
    Retired
    Location:
    Michigan USA
    Balance:
    9,176Coins
    Ratings:
    +2,156 / 19 / -1
    My Motion Simulator:
    3DOF, DC motor, Arduino, Motion platform, 6DOF
    Springs?
    • Agree Agree x 1
  7. Den1922

    Den1922 New Member

    Joined:
    Feb 7, 2020
    Messages:
    11
    Balance:
    149Coins
    Ratings:
    +8 / 0 / -0
    My Motion Simulator:
    2DOF, Arduino
    Springs it's a good idea, sometimes passive system will be efficace too ;)
  8. PMK

    PMK Member

    Joined:
    Jun 12, 2018
    Messages:
    43
    Location:
    Australia
    Balance:
    125Coins
    Ratings:
    +8 / 0 / -0
    Here's some pics of the full DIY rig. It's literally just been developed by bolting on parts as I got more and more into sim racing. I designed it so I could adjust everything independently. (wheel height, angle, seat position, pedal position, etc)

    86180369_530861331120573_8972838614429859840_n.jpg 86174044_1250532005146321_5726431719108640768_n.jpg
  9. PMK

    PMK Member

    Joined:
    Jun 12, 2018
    Messages:
    43
    Location:
    Australia
    Balance:
    125Coins
    Ratings:
    +8 / 0 / -0
    I'm actually quite surprised by the amount of tension these little things are able to provide. It's nothing amazing and won't punch the air out of your lungs but you can feel bumps in the road and braking forces through them. I drove around in LFS for about an hour yesterday and the servos never shut down or backed off from over heating.

    I fully agree that the wiper motors are probably the best way to go, however I got 5 of those servo's for $30 and had everything else to get this setup in a few hours.
    I've been playing with the idea of some stronger 50kg/cm servos.
    (http://www.kingmaxhobby.com/pd.jsp?id=22&nSL=[1,2,4,12,8,9,10,5,6,7]#skeyword=DCS16942&_pp=0_35)
    I think at this point it's probably better to go down the wiper motor route as they'll be faster, quieter, and more powerful.
    I'm planning to build a 2DoF seat mover anyway so I need to learn the wiper motor setup at some point.


    I set them to a 'zero' position in SimTools and attatched them to the servo's at a slightly above horizontal angle. That way deceleration forces result in the belt loosening. I'm using the the heave and sway degrees of freedom to actuate them. The servo's are honestly only moving a couple of degree's once the belts are tight on me (because they're stalling...) but it's enough to give an effect.


    Yup! I've also been thinking about this. As long as I find a spring that's the right stiffness I can limit the total force that the servo's need to exert.
    Another idea is to just soft mount the servo's and let the body/chair/belt/softmount system act as a sort of spring once I have stronger motors/servos.
    • Informative Informative x 1
  10. PMK

    PMK Member

    Joined:
    Jun 12, 2018
    Messages:
    43
    Location:
    Australia
    Balance:
    125Coins
    Ratings:
    +8 / 0 / -0
    I meant heave and surge*
    Is there no edit functions for our own posts?
  11. Historiker

    Historiker Dramamine Adict Gold Contributor

    Joined:
    Dec 16, 2010
    Messages:
    2,158
    Occupation:
    Retired
    Location:
    Michigan USA
    Balance:
    9,176Coins
    Ratings:
    +2,156 / 19 / -1
    My Motion Simulator:
    3DOF, DC motor, Arduino, Motion platform, 6DOF
    I believe that has to do with the number of posts that you have. You get those options after a few posts. Not sure, but it should say in the FAQ section.
    • Disagree Disagree x 1
  12. wannabeaflyer2

    wannabeaflyer2 Well-Known Member

    Joined:
    Jun 12, 2015
    Messages:
    724
    Location:
    london uk
    Balance:
    8,286Coins
    Ratings:
    +950 / 7 / -0
    My Motion Simulator:
    2DOF, Arduino, Motion platform, 6DOF
    Hi @PMK thanks for the info , sketching some ideas now so thanks for this idea .. gonna hit nutty makeonothihose mode :)
    • Like Like x 1
  13. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    20,460
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    144,596Coins
    Ratings:
    +10,741 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    • Informative Informative x 1
  14. PMK

    PMK Member

    Joined:
    Jun 12, 2018
    Messages:
    43
    Location:
    Australia
    Balance:
    125Coins
    Ratings:
    +8 / 0 / -0
    Can anyone suggest what sort of spec motors I'd want to be looking at for a project like this?

    I can get 2 50kg/cm servo's for around $80(AUD) total.
    https://www.aliexpress.com/item/329...hweb0_0,searchweb201602_10,searchweb201603_55

    I'm very tempted to just continue down the servo's route as the setup is much more simple (and cheaper?) compared to configuring the whole wiper-motor setup with pots, motor shields, PID tuning, etc
  15. adgun

    adgun Active Member

    Joined:
    Jan 28, 2008
    Messages:
    493
    Occupation:
    mechanic
    Location:
    Netherlands
    Balance:
    5,540Coins
    Ratings:
    +131 / 3 / -0
    Hi
    Youre motors give 5NM stall torque, a normal wippermotor is 5-6NM at rated torque.
    With a fuw it can be done , a GS4 seat is build the same way.
    Regards Ad
  16. Moe Colontonio

    Moe Colontonio Member Gold Contributor

    Joined:
    Dec 9, 2017
    Messages:
    118
    Location:
    New Jersey USA
    Balance:
    750Coins
    Ratings:
    +30 / 1 / -0
    My Motion Simulator:
    3DOF
    Forgive my ignorance, but what's an fuw?