Controlling gimbal's angular position with encoders of the motors?
  • Hello, I'm leaving this question as a very beginner :)

    I'm planning to purchase a commercial gimbal HW controlled by SimpleBGC 32-bit board
    and want to use it like a Pan-tilt device.
    Which means, I want to control the Yaw and Pitch angle by sending real-time serial commands from PC.

    The angular resolution and accuracy of rotation are very critical in my application.
    I checked the manual briefly, and found "MODE_ANGLE" in "CMD_CONTROL" command and have some questions about it.
    (The unit of the rotation angle : 0,0219~~ degree,
    and the gimbal manufacturer says they used 14-bit encoders for their motors.)

    1. Is the rotation angle controlled and measured by IMUs?
    Or if the motor has an encoder, is the angle measured by the encoder of the motor?
    (As the IMUs are quite noisy, I think using the encoders will be better in my case.)

    2. (if the angle is controlled & measured by IMU)
    Is there any commands to measure and control the angular position of the gimbal by using encoders?

    3. (if it is possible to control gimbals by encoders)
    Is there any Firmware or Controller board version limitations to control the gimbal by using encoders?
    (like "controlling by encoders is only supported with SimpleBGC ver. x.x and above")

    4. Lastly, is there any way to serial control the gimbal with higher resolution than 0.0219~ degree?

    I thank everyone who reads this in advance :)
  • 1. Encoders are better suited for measuring it rotation angle measurement than IMUs.

    3. Since 2019, our controllers support encoders so there should be no problem. If your controller is older than 2019, it may cause a problem from software point of view.
  • You could always read the current encoder angle, compare with the desired angle, and tell the IMU to move by the difference. But this is an indirect step and I'm pretty sure the response time will be slower.
  • Q11 Could you clarify what is meant by
    Using encoders with the SimpleBGC 32 controllers Version: 0.19
    "Using encoders with the SimpleBGC32 controller board gives the following advantages:
    2. Provides full information about the position of a camera relative to a frame"
    "High resolution is not strictly required, because encoders are not used in a closed loop control."?

    Q12 Could you publish a schematic controller diagram with the contributions of the IMU gyro/accel and the encoders contribution to gimbal operation?

    Q13 For very long duration (20 hour) applications where increasing (less acceleration bias) or decreasing (less gyro drift) gyro trust is not possible, would it be feasible to have a periodic inflight (high disturbance) reset of the IMU based on the encoder position?