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Re: [Paparazzi-devel] Tiltrotor-Project
From: |
notoriou5 |
Subject: |
Re: [Paparazzi-devel] Tiltrotor-Project |
Date: |
Wed, 22 Jun 2016 08:03:03 -0700 (MST) |
Hi Sergey,
I really do have issues with vibration. I already balanced my propellers but
it did not change much. I think my frame is just not stiff enough. This
could be a reason for some of the unstable behavior. Maybe I put a metal
sheet under it, need it later anyway to simulate some kind of wing for the
aerodynamic forces.
Besides the vibration I still do not get rid of the rotation completely.
These are the steps I did to reduce it:
1) Activate my MAG:
<subsystem name="ahrs" type="int_cmpl_quat"/>
<configure name="USE_MAGNETOMETER" value="TRUE"/>
2) Changed the values of the Motor Matrix to reduce the effect of different
momentum in the front engine:
motor_mixing.roll_coef[0] = 0;
motor_mixing.roll_coef[1] = 0;
motor_mixing.roll_coef[2] = 80;
motor_mixing.roll_coef[3] = -80;
motor_mixing.pitch_coef[0] = 70;
motor_mixing.pitch_coef[1] = 70;
motor_mixing.pitch_coef[2] = -70;
motor_mixing.pitch_coef[3] = -70;
motor_mixing.yaw_coef[0] = -150;
motor_mixing.yaw_coef[1] = 150;
motor_mixing.yaw_coef[2] = 0;
motor_mixing.yaw_coef[3] = 0;
motor_mixing.thrust_coef[0] = 140;
motor_mixing.thrust_coef[1] = 170;
motor_mixing.thrust_coef[2] = 250;
motor_mixing.thrust_coef[3] = 250;
3) Put an extra line into the motor_mixing.c to compensate the YAW momentum
during a ROLL movement:
for (i = 0; i < MOTOR_MIXING_NB_MOTOR; i++) {
motor_mixing.commands[i] = motor_mixing.trim[i] +
motor_mixing.roll_coef[i] * in_cmd[COMMAND_ROLL] +
motor_mixing.pitch_coef[i] * in_cmd[COMMAND_PITCH] +
motor_mixing.thrust_coef[i] * in_cmd[COMMAND_THRUST];
/*yaw combensation (tiltrotor) from a roll-command */
if ( i <= 1) {
motor_mixing.commands[i] += 2.5*motor_mixing.roll_coef[i+2] *
in_cmd[COMMAND_ROLL];
} [...] }
I know that I hard programmed these files. I still need to make it
compatible with all the other modells, but that is not priority number one
for now.
I adjusted the PID Values and he is flying "okay" for now. It still shows
the vibrations I mentioned at first and the YAW movement is still there. Not
as bad as in the beginning but not completely gone either. This is the
output of a telemetry file:
<http://lists.paparazziuav.org/file/n18094/Screenshot_YAW_16_06_22__17_29_24.png>
He is not really reaching the value. Any tips what else could help? Maybe
some more settings in the AHRS section?
Thanks to everyone.
Kevin
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