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Petr Ledvina 2015-02-07 17:01:53 +01:00
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docs/development/PID Internals.md
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### IO variables
gyroData/8192*2000 = deg/s
gyroData/4 ~ deg/s
`gyroData/8192*2000 = deg/s`
rcCommand - -500-500 nominal, but is scaled with rcRate/100, max +-1250
`gyroData/4 ~ deg/s`
inclination - in 0.1 degree, default 50 degrees (500 units)
`rcCommand` - `<-500 - 500>` nominal, but is scaled with `rcRate/100`, max +-1250
axisPID - output to mixer, will be added to throttle(1000-2000), output range is <minthrottle, maxthrottle> (default <1150 - 1850>)
`inclination` - in 0.1 degree, default 50 degrees (500)
`axisPID` - output to mixer, will be added to throttle(`<1000-2000>`), output range is `<minthrottle, maxthrottle>` (default `<1150 - 1850>`)
### PID controller 0, "MultiWii" (default)
## Leveling term
#### Leveling term
```
error = constrain(2*rcCommand[axis], limit +- max_angle_inclination) - inclination[axis]
P = constrain(P8[PIDLEVEL]/100 * error, limit +- D8[PIDLEVEL] * 5)
P = constrain(P8[PIDLEVEL]/100 * error, limit +- 5 * D8[PIDLEVEL])
I = intergrate(error, limit +-10000) * I8[PIDLEVEL] / 4096
## Gyro term
```
#### Gyro term
```
P = rcCommand[axis];
error = rcCommand[axis] * 10 * 8 / pidProfile->P8[axis] - gyroData[axis] / 4; (conversion so that error is in deg/s ?)
I = integrate(error, limit +-16000) / 10 / 8 * I8[axis] / 100 (conversion back to mixer units ?)
```
reset I term if
- axis rotation rate > +-64deg/s
- axis is YAW and rcCommand>+-100
- axis rotation rate > +-64deg/s
- axis is YAW and rcCommand>+-100
## Mode dependent mix(yaw is always from gyro)
##### Mode dependent mix(yaw is always from gyro)
HORIZON - proportionally according to max deflection
Gyro - gyro term
Angle - leveling term
- HORIZON - proportionally according to max deflection
## Gyro stabilization
- gyro - gyro term
- ANGLE - leveling term
#### Gyro stabilization
```
P = -gyroData[axis] / 4 * dynP8 / 10 / 8
D = -mean(diff(gyroData[axis] / 4), 3) * 3 * dynP8 / 32
D = -mean(diff(gyroData[axis] / 4), over 3 samples) * 3 * dynP8 / 32
```