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APM_Control : Moved scaler on roll and pitch integrator to be before integrator

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This means that the value of aileron and elevator trim offset won't change with airspeed
This commit is contained in:
Paul Riseborough 2013-10-21 17:58:46 +11:00 committed by Andrew Tridgell
parent 8e62035328
commit 97cdd36dd8
2 changed files with 11 additions and 7 deletions
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8
libraries/APM_Control/AP_PitchController.cpp
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@ -125,12 +125,14 @@ int32_t AP_PitchController::_get_rate_out(float desired_rate, float scaler, bool
float rate_error = (desired_rate - ToDeg(omega_y)) * scaler;
// Multiply pitch rate error by _ki_rate and integrate
// Scaler is applied before integrator so that integrator state relates directly to elevator deflection
// This means elevator trim offset doesn't change as the value of scaler changes with airspeed
// Don't integrate if in stabilise mode as the integrator will wind up against the pilots inputs
if (!disable_integrator && _K_I > 0) {
float ki_rate = _K_I * _tau;
//only integrate if gain and time step are positive and airspeed above min value.
if (dt > 0 && aspeed > 0.5f*float(aparm.airspeed_min)) {
float integrator_delta = rate_error * ki_rate * delta_time;
float integrator_delta = rate_error * ki_rate * delta_time * scaler;
if (_last_out < -45) {
// prevent the integrator from increasing if surface defln demand is above the upper limit
integrator_delta = max(integrator_delta , 0);
@ -145,7 +147,7 @@ int32_t AP_PitchController::_get_rate_out(float desired_rate, float scaler, bool
}
// Scale the integration limit
float intLimScaled = _imax * 0.01f / scaler;
float intLimScaled = _imax * 0.01f;
// Constrain the integrator state
_integrator = constrain_float(_integrator, -intLimScaled, intLimScaled);
@ -158,7 +160,7 @@ int32_t AP_PitchController::_get_rate_out(float desired_rate, float scaler, bool
// Note the scaler is applied again. We want a 1/speed scaler applied to the feed-forward
// path, but want a 1/speed^2 scaler applied to the rate error path.
// This is because acceleration scales with speed^2, but rate scales with speed.
_last_out = ( (rate_error * _K_D) + _integrator + (desired_rate * kp_ff) ) * scaler;
_last_out = ( (rate_error * _K_D) + (desired_rate * kp_ff) ) * scaler + _integrator;
// Convert to centi-degrees and constrain
return constrain_float(_last_out * 100, -4500, 4500);

10
libraries/APM_Control/AP_RollController.cpp
View File

@ -117,12 +117,14 @@ int32_t AP_RollController::_get_rate_out(float desired_rate, float scaler, bool
aspeed = 0.0f;
}
// Multiply roll rate error by _ki_rate and integrate
// Multiply roll rate error by _ki_rate, apply scaler and integrate
// Scaler is applied before integrator so that integrator state relates directly to aileron deflection
// This means aileron trim offset doesn't change as the value of scaler changes with airspeed
// Don't integrate if in stabilise mode as the integrator will wind up against the pilots inputs
if (!disable_integrator && ki_rate > 0) {
//only integrate if gain and time step are positive and airspeed above min value.
if (dt > 0 && aspeed > float(aparm.airspeed_min)) {
float integrator_delta = rate_error * ki_rate * delta_time;
float integrator_delta = rate_error * ki_rate * delta_time * scaler;
// prevent the integrator from increasing if surface defln demand is above the upper limit
if (_last_out < -45) {
integrator_delta = max(integrator_delta , 0);
@ -137,7 +139,7 @@ int32_t AP_RollController::_get_rate_out(float desired_rate, float scaler, bool
}
// Scale the integration limit
float intLimScaled = _imax * 0.01f / scaler;
float intLimScaled = _imax * 0.01f;
// Constrain the integrator state
_integrator = constrain_float(_integrator, -intLimScaled, intLimScaled);
@ -146,7 +148,7 @@ int32_t AP_RollController::_get_rate_out(float desired_rate, float scaler, bool
// Note the scaler is applied again. We want a 1/speed scaler applied to the feed-forward
// path, but want a 1/speed^2 scaler applied to the rate error path.
// This is because acceleration scales with speed^2, but rate scales with speed.
_last_out = ( (rate_error * _K_D) + _integrator + (desired_rate * kp_ff) ) * scaler;
_last_out = ( (rate_error * _K_D) + (desired_rate * kp_ff) ) * scaler + _integrator;
// Convert to centi-degrees and constrain
return constrain_float(_last_out * 100, -4500, 4500);