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Setting up an unbalanced gimbal
  • aganz
    Hi all. Due to space constraints and a design beyond my control, I am trying to cobble together a gimbal system that will start out with a cantilevered pitch. A mechanical stopper is in place to ensure the powered-off position isn't gimbal lock.

    The hardware:
    BaseCamBGC Pro Controller, board 4.2, running firmware 2.69b6, API v2
    Main IMU: SBGC32 CAN IMU, soldered for terminal bus, connected to the MCU's CAN port
    External IMU: GPS IMU v1.2, connected to UART2 pins on the Interface Board
    3 Motors: iPower GM6208 150 Brushless Gimbal Motor, 24N28P, (comes assemebled with encoders), connected to Power Board
    Encoders: AS5048A, wired for PWM, connected to PWM ports in the SPI connection

    My problem:
    From what I can tell from the response to another post along with reading the encoders guide, the encoders will not work unless they are calibrated, and the calibration requires stabilization. Given the nature of the cantilevered design, I am not really able to accomplish this well. I can set the motor power settings high enough to achieve stabilization, but when I start the calibration sequence, it fails with "wrong number of poles or inversion". Is there a way to get these encoders calibrated and move forward?

    Thanks for your help!
  • alexmosalexmos
    Hello,. Yes you are right, to calibrate encoders, system should be perfectly balanced. The reason is that positioning of rotor relative to stator should be done by electrical field only, and any external forces are not allowed. There are no other ways to calibrate encoders rather then make system balanced, even temporally by counterweights is a solution.
  • aganz
    I will try to counterbalance the system to create stability. Do the motors need to be able to move freely for calibration, or can they be fixed firmly in place?

    Thank you very much for the quick reply!
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