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.

My DIY 6DOF - 80/20 - AMC - Clearpath Servos

Discussion in 'DIY Motion Simulator Projects' started by Nisch, Jun 4, 2019.

  1. hexpod

    hexpod http://heXpod.xyz

    Joined:
    Apr 18, 2016
    Messages:
    715
    Location:
    berlin
    Balance:
    4,713Coins
    Ratings:
    +196 / 2 / -0
    My Motion Simulator:
    DC motor, 6DOF
    That’s what I would assume as well !
  2. Nisch

    Nisch Member Gold Contributor

    Joined:
    Feb 20, 2019
    Messages:
    44
    Occupation:
    Software Developer
    Location:
    Phoenix, AZ
    Balance:
    301Coins
    Ratings:
    +94 / 0 / -0
    My Motion Simulator:
    6DOF
    I have inductive sensors set up for each arm and have the servos setup to sensor based homing. I have a 24V line that provides the enable signal via remote controlled outlet. The calibration has only been performed once and retains it regardless of powering down. The only thing that's done repeatedly is the homing sequence.
  3. Trip Rodriguez

    Trip Rodriguez VR Pilot

    Joined:
    May 8, 2016
    Messages:
    553
    Location:
    Lake Ariel, Pennsylvania
    Balance:
    3,219Coins
    Ratings:
    +240 / 3 / -0
    My Motion Simulator:
    6DOF
    Hey guys, I'm afraid to ask. This RAS looks like exactly what I need because smoothness is my main goal, butthey say it's proprietary. Are we going to have equivalent functionality available for my AASD-20A based servo setup or am I going to be left out in the cold on this one? I went to the website to have them delay my shipment until you guys reply but it's too late, just in the last couple hours my order left the warehouse. D=

    Clearpath would have been much more expensive for lower power servos and I didn't know anything about the existence of this RAS thing. I'm a bit distressed now.

    PS- Well, if getting Clearpath instead of the AASD servos really is important maybe I can build some real nice linear actuators and then sell the AASD's as complete actuators ready to go. Probably make a profit that way instead of take a big kick to the nuts.... It's a PITA being a pilot instead of a driver. The racers don't really have these problems with smoothness.
    Last edited: Oct 13, 2019
  4. Dirty

    Dirty Active Member Gold Contributor

    Joined:
    Oct 15, 2017
    Messages:
    315
    Occupation:
    All the way up front.
    Location:
    Germany
    Balance:
    3,439Coins
    Ratings:
    +301 / 1 / -0
    Don't worry too much about it. This RAS thing is essentially just a 3rd order lowpass filter. You have these filters in FlyPT_Mover, in Nutkicker and I think they are available in simtools as well.

    If your rig is rigid and sturdy, you won't have to worry about it at all. In the video they are using a mass on a springy metal sheet. That metal sheet has a resonance frequency and it is THAT frequency that the RAS lowpass filter cancels out. If your rig is sturdy enough it's resonance frequency is higher than anything you will ever experience, so no need to filter anything out.

    Dirty :)
  5. hexpod

    hexpod http://heXpod.xyz

    Joined:
    Apr 18, 2016
    Messages:
    715
    Location:
    berlin
    Balance:
    4,713Coins
    Ratings:
    +196 / 2 / -0
    My Motion Simulator:
    DC motor, 6DOF
    Well, I am not sure you can replace the internal servo filtering with 3x LPF.
    In my scenario (Thanos board with SSI feedback) clearly not. Without RAS, the platform is unable to keep the position, shaking without any signal coming in.
  6. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

    Joined:
    Jul 6, 2017
    Messages:
    562
    Occupation:
    Electronics Engineer
    Location:
    United States
    Balance:
    3,867Coins
    Ratings:
    +474 / 4 / -0
    My Motion Simulator:
    AC motor, Joyrider, Motion platform, 4DOF, 6DOF
    Don't get confused. Clearpath servomotors are different from the AASD servomotors, the clearpath are essentially BLDC motors low voltage (48v - 75v DC) and NEED RAS to avoid oscillation trying to lock or hold position without noise.

    The AASD servomotors are 110v-220v AC type servos, and work with sinusoidal 3phase PWM, and the driver performs full PID and has several filters and parameters that ensure there will be smooth transition between positions (even between steps) and no noise at all.

    I have worked with both clearpath and AASD servos and I can tell here clear winner on accuracy and positioning noise is the AASD!
    • Informative Informative x 2
  7. hexpod

    hexpod http://heXpod.xyz

    Joined:
    Apr 18, 2016
    Messages:
    715
    Location:
    berlin
    Balance:
    4,713Coins
    Ratings:
    +196 / 2 / -0
    My Motion Simulator:
    DC motor, 6DOF
    Cool. Can we use those servomotors in cranked systems?

    Are they fitting in nema34 flange ?
    What’s their max speed and continue and peak torque curves ?
    Last edited: Oct 13, 2019
  8. Trip Rodriguez

    Trip Rodriguez VR Pilot

    Joined:
    May 8, 2016
    Messages:
    553
    Location:
    Lake Ariel, Pennsylvania
    Balance:
    3,219Coins
    Ratings:
    +240 / 3 / -0
    My Motion Simulator:
    6DOF
    I believe they are NEMA 32, I think some people have used them for cranked but I'm not 100% certain. Attaching an image with specs, I cropped it to show the specs only for the motors most of Thanos AAMC users are using, and the more powerful ones I purchased. I got the set of six for $1,600 USD including shipping and tax!

    Specs:
    AASD motor specs.jpg
    Dimensions:
    aasddimensions.jpg
    • Like Like x 2
  9. Trip Rodriguez

    Trip Rodriguez VR Pilot

    Joined:
    May 8, 2016
    Messages:
    553
    Location:
    Lake Ariel, Pennsylvania
    Balance:
    3,219Coins
    Ratings:
    +240 / 3 / -0
    My Motion Simulator:
    6DOF
    @Dirty @Thanos @hexpod Thanks for the info and the reassurances guys.

    I'm hoping the PWM noise won't be as bad as my current setup, but I can just drown it out with audio from the simulator regardless.

    Aside from that the value for the money seems incredible with Thanos' recommended setup here. Lots of power, basically plug and play, and with no need for external sensors all for this kind of money is great! Clearpath look fantastic, but to get the same kind of power I think it would have cost me about $2,500 more to go that route.

    @Thanos what I was looking for with this RAS thing was to get rid of the "jerk" at the beginning of a big simulator movement. Hopefully I'll be able to do this with the FlyPT/Simtools/HeXpod filters once I get my AASD rig built. The whole reason I'm building a new sim is to get it silky smooth, my first one works well otherwise.
  10. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

    Joined:
    Jul 6, 2017
    Messages:
    562
    Occupation:
    Electronics Engineer
    Location:
    United States
    Balance:
    3,867Coins
    Ratings:
    +474 / 4 / -0
    My Motion Simulator:
    AC motor, Joyrider, Motion platform, 4DOF, 6DOF
    The servomotors are really quiet! The only thing you may hear are the mechanics and perhaps any fans running on your PC... see here:

  11. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

    Joined:
    Jul 6, 2017
    Messages:
    562
    Occupation:
    Electronics Engineer
    Location:
    United States
    Balance:
    3,867Coins
    Ratings:
    +474 / 4 / -0
    My Motion Simulator:
    AC motor, Joyrider, Motion platform, 4DOF, 6DOF
    Also its totally doable with planetary gearboxes, see a photo of a rig with similar servomotors (but other controller that needs feedback).

    2019-08-18 16.33.43.jpg
    • Winner Winner x 1
  12. Trip Rodriguez

    Trip Rodriguez VR Pilot

    Joined:
    May 8, 2016
    Messages:
    553
    Location:
    Lake Ariel, Pennsylvania
    Balance:
    3,219Coins
    Ratings:
    +240 / 3 / -0
    My Motion Simulator:
    6DOF
    Awesome! In the one video I was hearing the AC PWM high pitch noise like my VFD setup makes. I'll be happy if it's drastically reduced and extremely happy if it's not audible. I do expect the noise from the mechanical parts, I've watched lots of videos of various linear actuator rigs running.
  13. SilentChill

    SilentChill Problem Maker

    Joined:
    Jul 19, 2014
    Messages:
    2,518
    Occupation:
    Railway Maintenance
    Location:
    Morecambe, Lancashire, England
    Balance:
    19,087Coins
    Ratings:
    +3,234 / 31 / -0
    My Motion Simulator:
    DC motor, Arduino, Motion platform, 6DOF

    I know @shannonb1 may of gave up on his SFX due to the high pitch frequency, I know I can hear it from the many videos I've watched.
  14. Dirty

    Dirty Active Member Gold Contributor

    Joined:
    Oct 15, 2017
    Messages:
    315
    Occupation:
    All the way up front.
    Location:
    Germany
    Balance:
    3,439Coins
    Ratings:
    +301 / 1 / -0
    That's interesting! Maybe there really is more to it internally, but from this video it appears the main component of RAS is that it limits the...
    ...rate of change of the...
    ...rate of change of the...
    ...rate of change of the...
    ...rate of change of the...
    ...position.

    If you do these point-to-point moves like in the video then I'd expect RAS to make a huuuuge difference. If the incoming signal is already a 3rd order LP-filtered signal, I'd be surprised if it made a noticeable difference. A nice surprise none the less. :)

    Don't get me wrong, I am a big fan of these motors and more than willing to spend money on them, I just doubt that RAS is the panacea to "shaky-rig-itis".
    Perhaps @Teknic_Servo can shed some light onto this :) Would be super cool to hear from someone on the "inside" :)

    Cheers,... :)
    • Like Like x 1
  15. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

    Joined:
    Jul 6, 2017
    Messages:
    562
    Occupation:
    Electronics Engineer
    Location:
    United States
    Balance:
    3,867Coins
    Ratings:
    +474 / 4 / -0
    My Motion Simulator:
    AC motor, Joyrider, Motion platform, 4DOF, 6DOF




    • Like Like x 2
  16. SilentChill

    SilentChill Problem Maker

    Joined:
    Jul 19, 2014
    Messages:
    2,518
    Occupation:
    Railway Maintenance
    Location:
    Morecambe, Lancashire, England
    Balance:
    19,087Coins
    Ratings:
    +3,234 / 31 / -0
    My Motion Simulator:
    DC motor, Arduino, Motion platform, 6DOF
    Ahh yes very good that's soo much better :)

    Dunno if @shannonb1 knows about this but that would solve his problem for sure
  17. Trip Rodriguez

    Trip Rodriguez VR Pilot

    Joined:
    May 8, 2016
    Messages:
    553
    Location:
    Lake Ariel, Pennsylvania
    Balance:
    3,219Coins
    Ratings:
    +240 / 3 / -0
    My Motion Simulator:
    6DOF
    Excellent! Thanks for the videos @Thanos
    Sounds like I will be very happy with the improvement. Ba dum tsh
    • Agree Agree x 1
  18. shannonb1

    shannonb1 Well-Known Member

    Joined:
    Mar 12, 2008
    Messages:
    1,107
    Occupation:
    Sales Intelligence
    Location:
    Virginia
    Balance:
    8,835Coins
    Ratings:
    +596 / 5 / -0
    My Motion Simulator:
    2DOF, JRK
    i switched it over to 110v, still hear it but quieter...not sure what I would do here, I am grounded.
  19. hexpod

    hexpod http://heXpod.xyz

    Joined:
    Apr 18, 2016
    Messages:
    715
    Location:
    berlin
    Balance:
    4,713Coins
    Ratings:
    +196 / 2 / -0
    My Motion Simulator:
    DC motor, 6DOF
    @Thanos do those guys have any catalogue with ratings for other models than 80 and 90 that we see on alibaba?

    It seems I’ve mixed up models looking on the pdf manual @Trip Rodriguez was providing.
  20. hexpod

    hexpod http://heXpod.xyz

    Joined:
    Apr 18, 2016
    Messages:
    715
    Location:
    berlin
    Balance:
    4,713Coins
    Ratings:
    +196 / 2 / -0
    My Motion Simulator:
    DC motor, 6DOF
    I just asked for prices

    To handle 4Nm with reduction 40 (two stages) you can deal with 90 size for 300$. This would give you an insane speed of 60RPM

    If you want reduce the speed by half and keep the torque abilities of the motor you could go with reduction 80 in size 115 (3 stages) for 500$