slip/skip angle ?

[PhiJu5]

Hello,

No issue here, just a question.

I have a 2021 USFSMAX module and use your 2021 library in a RC glider to have telemetry
data pitch/roll/yaw/Gz with a Teensy . Works great thanks to your library (the code to read the data is below).
I would like to add a slip/skip angle telemetry data but have no idea how to compute it.

There was an RC 3D gyro having and "Automatic Turn Coordination", the Eagle tree Guardian 2D/3D Stabilizer (discontinued):
"Automatic Turn Coordination will cause the Guardian to employ the “step on the ball” method of actuating
your Rudder for you. As you enter a banked turn, the Guardian will assert a coordinating response on the Rudder automatically.
This deflection is completely based on the side-to-side g-force measured by the Guardian and does not introduce any movement on
the Ailerons. This mode is great for models that skid easily.
Expected behavior here is that on the bench, the Guardian will introduce a Rudder movement that will yaw the model towards the
direction it is being rolled. For instance, if a stationary plane is rolled to the right, the Rudder should assert a right yaw
moment to follow the detected turn. Since this is based on horizontal g-force, the Guardian may exhibit different behavior in
the air in a “skid” condition where the model is moving one"

Do you know how to compute this slip/skip angle with the USFSMAX (if possible) ?

(From a French forum https://f3news.1fr1.net/t15586-derive-assistee, hard to translate correctly:
drift is the "Y" of the 3 XYZ force sensors of the gyro, X in fuselage axis, Y perpendicular to X and parallel to the wing)

Currently, my teensy code loop to catch data is:

if (usfsmax.quaternionReady()) {
usfsmax.readQuat(q);
qw = q[0];
qx = q[1];
qy = q[2];
qz = q[3];
gravityZ = qw * qw - qx * qx - qy * qy + qz * qz;
roll = atan2f(2.0f * (qw * qx + qy * qz), qw * qw - qx * qx - qy * qy + qz * qz);
pitch = -asinf(2.0f * (qx * qz - qw * qy));
yaw = atan2f(2.0f * (qx * qy + qw * qz), qw * qw + qx * qx - qy * qy - qz * qz);
roll *= 180.0f / PI;
pitch *= (180.0f) / PI;
yaw *= 180.0f / PI;
roll = -roll; // fix position
yaw += getEepromCfgFloat((int)EepromData::YawFix);
yaw = fmodf(yaw + 360.0f, 360.0f);

Thanks.

Regards.

[gregtomasch]

I do not know how to do this “Off the top of my head”. Have you reviewed the literature on the subject of coordinated turn flight dynamics? From: PhiJu5 ***@***.***> Sent: Tuesday, February 21, 2023 12:52 PM To: gregtomasch/USFSMAX ***@***.***> Cc: Subscribed ***@***.***> Subject: [gregtomasch/USFSMAX] slip/skip angle ? (Issue #6) Hello, No issue here, just a question. I have a 2021 USFSMAX module and use your 2021 library in a RC glider to have telemetry data pitch/roll/yaw/Gz with a Teensy . Works great thanks to your library (the code to read the data is below). I would like to add a slip/skip angle telemetry data but have no idea how to compute it. There was an RC 3D gyro having and "Automatic Turn Coordination", the Eagle tree Guardian 2D/3D Stabilizer (discontinued): "Automatic Turn Coordination will cause the Guardian to employ the “step on the ball” method of actuating your Rudder for you. As you enter a banked turn, the Guardian will assert a coordinating response on the Rudder automatically. This deflection is completely based on the side-to-side g-force measured by the Guardian and does not introduce any movement on the Ailerons. This mode is great for models that skid easily. Expected behavior here is that on the bench, the Guardian will introduce a Rudder movement that will yaw the model towards the direction it is being rolled. For instance, if a stationary plane is rolled to the right, the Rudder should assert a right yaw moment to follow the detected turn. Since this is based on horizontal g-force, the Guardian may exhibit different behavior in the air in a “skid” condition where the model is moving one" Do you know how to compute this slip/skip angle with the USFSMAX (if possible) ? (From a French forum https://f3news.1fr1.net/t15586-derive-assistee, hard to translate correctly: drift is the "Y" of the 3 XYZ force sensors of the gyro, X in fuselage axis, Y perpendicular to X and parallel to the wing) Currently, my teensy code loop to catch data is: if (usfsmax.quaternionReady()) { usfsmax.readQuat(q); qw = q[0]; qx = q[1]; qy = q[2]; qz = q[3]; gravityZ = qw * qw - qx * qx - qy * qy + qz * qz; roll = atan2f(2.0f * (qw * qx + qy * qz), qw * qw - qx * qx - qy * qy + qz * qz); pitch = -asinf(2.0f * (qx * qz - qw * qy)); yaw = atan2f(2.0f * (qx * qy + qw * qz), qw * qw + qx * qx - qy * qy - qz * qz); roll *= 180.0f / PI; pitch *= (180.0f) / PI; yaw *= 180.0f / PI; roll = -roll; // fix position yaw += getEepromCfgFloat((int)EepromData::YawFix); yaw = fmodf(yaw + 360.0f, 360.0f); Thanks. Regards. — Reply to this email directly, view it on GitHub <#6> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABL6PMWNKU3VL5PO4FGLTCDWYUTH7ANCNFSM6AAAAAAVDQHTXE> . You are receiving this because you are subscribed to this thread. <https://github.com/notifications/beacon/ABL6PMUQMKBWBRVOTXQZ7QLWYUTH7A5CNFSM6AAAAAAVDQHTXGWGG33NNVSW45C7OR4XAZNFJFZXG5LFVJRW63LNMVXHIX3JMTHF6A6IEI.gif> Message ID: ***@***.*** ***@***.***> >