Is there such a thing?
There’s a short guide about each parameter in this page:
http://copter.ardupilot.com/wiki/tuning/
But I’m looking to understand deeper.
Just to make it clear - It’s not the PID mechanism I’m looking to understand - It’s which PIDs control which mechanisms (What are the “plants” / “process”, and where is the feedback read from)
Here’s what I know, with questions :
-
Stabilize Controller - Roll/Pitch/Yaw (Only P) - In charge of converting the desired angle into a desired rotation rate which is then fed to the Rate controller.
– Questions:
---- Why are they only P gains?
---- What is the feedback? Gyro input?
EDIT: It just hit me - I now understand that the rotation rate in question the rotation of the quad, not the propeller rotation rate. So the feedback must be the gyro derivative, right? -
Rate Controller - Roll/Pitch/Yaw - Converts the desired rotation rate into a motor output. IMAX limits the I parameter to a certain maximum.
– Questions:
---- What is the feedback?
---- Why do we use an Imax instead of lowering I?
Altitude:
- Throttle Rate (PD)- Converts the position of the throttle in the RC radio (i.e: rate of climb or descent) to the acceleration. This is fed to:
- Throttle Accel (PID) - Converts the wanted acceleration into motor output
-
Altitude Hold (Only P) - Converts the change in altitude (or the altitude error) to a Throttle Rate (to be fed to the Throttle Rate controller
–Questions:
---- The Throttle Rate controller plant’s is acceleration, meaning it gets the accelerometer values as feedback, right? If so, what’s the Throttle Accel feedback?
---- The Throttle Rate controls the Throttle Accel. How do I use it? Say I want my quad to recover quickly from fast falls, which of these controllers should I change? Both?
---- Why don’t we use all PID gains on all controllers?
The rest are more simple to understand.
Sorry for asking so many questions. I’ll try to make a guide out of this when I’ll figure out everything.
Thanks a lot
Nitay