calibration of encoder failed
  • Hello, I have a problem to calibrate one of my encoders on my gimbal.

    My gimbal is balanced and calibrated. It is working fine if encoders are disabled. I am using a BaseCam SimpleBGC 32-bit with IFlight motors (GBM2804) and AS5048A encoders with PWM. I tested my gimbal both with 2.63b0 and 2.65b7 (BETA) firmware.
    There is a tilt angle of -45° on YAW axis.

    I do what is written in the encoders manual. The gimbal is balanced, PIDs are calibrated, poles are correct, follow mode and RC are disabled, the calibration values in "Encoder" tab are set to zero and gearing ratios are set to 1. If I press CALIB.EL FIELD the gimbal starts the calibration by moving each motor. In the end after having moved yaw motor, the system stops and the following message appears "Emergency stop : ENCODER CALIB. FAILED: wrong number of poles or inversion".

    I checked in hardware tab and my motor parameters are the wright ones : 14 poles as said on motor datasheet and no inversion problem as the gimbal works properly when encoders are disabled.
    If I disable only Yaw encoder, calibration of pitch and roll is ok and the system works well except that yaw motor consumes too much energy.
    The yaw encoder is okay as it delivers PWM signal on monitoring tab, there are around 16000 values for a 360° gear, I even tried to change the encoder but it had no effect.

    I already used the board with another 3 axis gimbal and with these very motors and encoders, the only difference was that yaw axis was vertical and not 45° inclined. the system functionned well with encoders.

    Do you have an idea why I can't calibrate my yaw encoder? Is it just because of the motor tilt angle?
  • Hello.
    I was made gimbal with the -45 degree YAW some time ago and add a partial support of such configuration in the firmware version 2.63 and above. But I don't remember was there any problem with the encoder calibration or not. Finally it was working for me well and enoders were calibrated.

    Did you set this parameter as described in the User Manual?
    http://ybex.com/d/wacc4n54cvyliwnhzb08ndepxd1na76m9t6ul84y.html

    I will test this gimbal with the latest 2.65b7 and let you know.
  • Hello, thank you for your answer,
    I did set the parameter correctly and the gimbal works well without yaw encoder. And as soon as I change my part between yaw and roll motor to have a vertical yaw axis, I can calibrate the yaw encoder.
  • Update: I made some tests. The "Tilt angle" parameter is NOT taken into account for the encoder calibration, so error checking is not correct: sometimes it passes, sometimes not. I have updated this procedure and now it successfull in 100% attempts. I will publish 2.65b8 beta version today or tomorrow.

    Note that YAW tilt angle is only PARTLY supported, so it might be other issues. If you find any strange things, please first compare it with the regular configuration, to evaluate is it related to a tilted YAW motor or not.
  • UPD: forget to say the encoders should be calibrated in normal position: ROLL and PITCH motor's axes are leveled, YAW tilted by 45 degrees to vertical.
  • My gimbal is now working fine, thank you very much.