petoi-camp-logo.png
English
EN
English
EN
Chinese
ZH
  • Forum

  • Shop

  • More

    Use tab to navigate through the menu items.
    Phillip Brush
    1d

    On Definition Rule Issues

    2
    0
    Chris Jerome
    Feb 15, 2020

    Raspbery Pi DMP issue and general question

    5
    1
    Hanna Ovr
    Aug 02

    Pest Control Software

    1
    0
    To see this working, head to your live site.
    • Categories
    • All Posts
    • My Posts
    Ana Shevchenko
    Feb 14, 2021
    Edited: Feb 14, 2021

    Servos seem stuck after switching poses

    in Basic Assembly and Setup

    Hi!


    I've posted here before and finally found the time to get back to figuring Nybble out. I managed to calibrate it, but now when I type "kbalance" in the serial monitor, instead of continuously switching between states, Nybble seems to move to an approximation of the "stand" position, and kind of stay that way, while the servos are still working. Nybble doesn't go into the "rest" position, unless I type "d".


    A video would explain it better (sorry for the cars noise in the background, you should still be able to hear the servos rumbling).







    The front left knee also seems to move a bit abnormally, but that is likely because I burnt its servo during incorrect calibration in the past and bought an almost identical substitute (it's still MG90D).


    I don't know how normal this is or how to fix it. Please help.

    4 comments
    0
    4 Comments
    R
    Rongzhong Li
    Feb 14, 2021

    As to Nybble's servos, yes. We ODMed the servos for the best performance on Nybble. We can send you a replacement after fulfilling the current Bittle orders.

    Like
    A
    Ana Shevchenko
    Feb 14, 2021
    Replying to

    Thank you, Rongzhong. You're always a pleasure to speak to. I also will be preordering Bittle next month, as my paycheck comes in.

    Like

    R
    Rongzhong Li
    Feb 14, 2021

    Hi, the MG90D is the problem. Though it looks the same as our kit servos, it has a different signal-to-angle ratio.


    You may change the value in OpenCat.h but it will require some efforts to find the magic number:


    byte servoAngleRanges[] =  {SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE,
                                SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE,
                                SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE,
                                SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE, SERVO_ANG_RANGE,
                               };


    We also optimized the motor, controller chip, and gear system of our kit servos for Nybble. It's much better than MG90D. We are going to open an AliExpress store later this year to offer replacement components with cheaper shipping options.

    Like
    A
    Ana Shevchenko
    Feb 14, 2021
    Replying to

    Thank you, I'll try to play around with these values. Is my only other option for now to wait until the parts come to AliExpress?

    Like
    4 comments
    Similar Posts
    • Servo Jitter
    • Stuck knee/servos - not able to pass the calibration
    • Servo mapping

    Pittsburgh, PA, USA | info@petoi.com 

    Privacy Policy

    © 2018 - 2021 Petoi LLC