How to create a custom motor mixer? - OctoX variant

DroneUnit · June 12, 2020, 4:41pm

Hi All,

I am hoping someone can help me. I looking to create/use a custom Ardu OctoX mixer that mimics DJI’s Octo layout so I can easily switch back and forth between controllers.

This is the default OctoV layout in ArduPilot:

This is what I need the custom motor mixer to do:
DJI Octo

How would I go about doing this?

Thanks!

iampete · June 12, 2020, 5:00pm

We have DJI x frame type 13,

github.com

ArduPilot/ardupilot/blob/243cfb5ffaae2e1ccfbd834e6790ff203f17aeb1/libraries/AP_Motors/AP_MotorsMatrix.cpp#L712


case MOTOR_FRAME_TYPE_I:
    add_motor_raw(AP_MOTORS_MOT_1, 0.333f, -1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  1);
    add_motor_raw(AP_MOTORS_MOT_2, -0.333f,  1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  5);
    add_motor_raw(AP_MOTORS_MOT_3,    1.0f, -1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 2);
    add_motor_raw(AP_MOTORS_MOT_4,  0.333f,  1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 4);
    add_motor_raw(AP_MOTORS_MOT_5, -0.333f, -1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 8);
    add_motor_raw(AP_MOTORS_MOT_6,   -1.0f,  1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 6);
    add_motor_raw(AP_MOTORS_MOT_7,   -1.0f, -1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  7);
    add_motor_raw(AP_MOTORS_MOT_8,    1.0f,  1.0f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  3);
    break;
case MOTOR_FRAME_TYPE_DJI_X:
    add_motor(AP_MOTORS_MOT_1,   22.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 1);
    add_motor(AP_MOTORS_MOT_2,  -22.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  8);
    add_motor(AP_MOTORS_MOT_3,  -67.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 7);
    add_motor(AP_MOTORS_MOT_4, -112.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  6);
    add_motor(AP_MOTORS_MOT_5, -157.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 5);
    add_motor(AP_MOTORS_MOT_6,  157.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  4);
    add_motor(AP_MOTORS_MOT_7,  112.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 3);
    add_motor(AP_MOTORS_MOT_8,   67.5f, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  2);
    break;
case MOTOR_FRAME_TYPE_CW_X:

DroneUnit · June 12, 2020, 5:16pm

Oh awesome, thanks! Didn’t realize there was more options if you use the parameters (vs just using the initial setup GUI). Just so I don’t mess things up, in the parameter list I would set:
Frame Class: Octa
Frame Type: DJIX

What is the difference between Octa VS OctaQuad? Octaquad mean X8?

DroneUnit · June 12, 2020, 5:24pm

Think I found a pretty scary mission planner glitch. If I go to the parameter list and change Frame Class/Frame Type all is well. This issue is if you click on Initial Setup->Frame Type it will auto change/write the frame type to the first in the list without the user doing anything (since DJIX is not in the GUI). In my case if I click frame type it changes the Frame Type to “Plus.” Any idea if there is anyway to prevent this from happening?

Proceeded to try QGroundControl. While it doesn’t reset the Frame Type, I am now getting a PreArm: check firmware or FRAME_CLASS error

iampete · June 12, 2020, 5:54pm

yes

Octaquad is 4 sets of coaxial.

If in doubt always check in the full list.

DroneUnit · June 12, 2020, 5:58pm

Thanks, any ideas for the flame_type reset in mission planner or Prearm error mentioned above?

iampete · June 12, 2020, 6:44pm

ah, that frame type is not in the stable release yet.