DCM Clarifications needed

Hello,

I'm trying to use William's DCM which was implemented in SF9DOF_AHRS_1_0 and in ArdupilotMega with a 5DOF IMU ( link: http://www.sparkfun.com/products/9268 ) and I have a couple of questions.

How do I calculate these constants: Kp_ROLLPITCH, Ki_ROLLPITCH, Kp_YAW, Ki_YAW assuming I run the DCM at 100 Hz.

I'm trying to use the same reference system used in SF9DOF AHRS:

Pitch positive on nose up, roll positive on the right wing down and their axis definitions: X axis pointing forward(the pins are in front of the X axis), Y axis pointing to the right, Z axis pointing down. But on the SF5DOF IMU I have,

X accelerometer axis is pointing forward, Y accelerometer axis is pointing to the left and Z accelerometer axis is pointing down, with this in mind, what should be on Gyro_vector[0]? Should it be Xrate which is actually roll? Or should it be YRate?

I have attached a photo in which you can see the actual placement.

Thanks in advance.

placement.png

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Replies

  • I have answered myself to one of the questions

    In Gyro_Vector I should have the turn rate in radians, in this order: x roll, y pitch, z yaw.

    Still, if I leave the constants used in Arduipilot/SF9DOF, I have to wait ~2-3 seconds to see the correct angle. Is there any way to calculate those or I have to experiment?

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