mirror of
https://github.com/ArduPilot/ardupilot
synced 2025-01-19 23:28:32 -04:00
442 lines
17 KiB
C++
442 lines
17 KiB
C++
/*
|
|
This program is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
// Code by Jon Challinger
|
|
// Modified by Paul Riseborough
|
|
//
|
|
|
|
#include <AP_HAL/AP_HAL.h>
|
|
#include "AP_RollController.h"
|
|
|
|
extern const AP_HAL::HAL& hal;
|
|
|
|
const AP_Param::GroupInfo AP_RollController::var_info[] = {
|
|
// @Param: 2SRV_TCONST
|
|
// @DisplayName: Roll Time Constant
|
|
// @Description: Time constant in seconds from demanded to achieved roll angle. Most models respond well to 0.5. May be reduced for faster responses, but setting lower than a model can achieve will not help.
|
|
// @Range: 0.4 1.0
|
|
// @Units: s
|
|
// @Increment: 0.1
|
|
// @User: Advanced
|
|
AP_GROUPINFO("2SRV_TCONST", 0, AP_RollController, gains.tau, 0.5f),
|
|
|
|
// @Param: 2SRV_P
|
|
// @DisplayName: Proportional Gain
|
|
// @Description: Proportional gain from roll angle demands to ailerons. Higher values allow more servo response but can cause oscillations. Automatically set and adjusted by AUTOTUNE mode.
|
|
// @Range: 0.1 4.0
|
|
// @Increment: 0.1
|
|
// @User: Standard
|
|
AP_GROUPINFO("2SRV_P", 1, AP_RollController, gains.P, 1.0f),
|
|
|
|
// @Param: 2SRV_D
|
|
// @DisplayName: Damping Gain
|
|
// @Description: Damping gain from roll acceleration to ailerons. Higher values reduce rolling in turbulence, but can cause oscillations. Automatically set and adjusted by AUTOTUNE mode.
|
|
// @Range: 0 0.2
|
|
// @Increment: 0.01
|
|
// @User: Standard
|
|
AP_GROUPINFO("2SRV_D", 2, AP_RollController, gains.D, 0.08f),
|
|
|
|
// @Param: 2SRV_I
|
|
// @DisplayName: Integrator Gain
|
|
// @Description: Integrator gain from long-term roll angle offsets to ailerons. Higher values "trim" out offsets faster but can cause oscillations. Automatically set and adjusted by AUTOTUNE mode.
|
|
// @Range: 0 1.0
|
|
// @Increment: 0.05
|
|
// @User: Standard
|
|
AP_GROUPINFO("2SRV_I", 3, AP_RollController, gains.I, 0.3f),
|
|
|
|
// @Param: 2SRV_RMAX
|
|
// @DisplayName: Maximum Roll Rate
|
|
// @Description: Maximum roll rate that the roll controller demands (degrees/sec) in ACRO mode.
|
|
// @Range: 0 180
|
|
// @Units: deg/s
|
|
// @Increment: 1
|
|
// @User: Advanced
|
|
AP_GROUPINFO("2SRV_RMAX", 4, AP_RollController, gains.rmax, 0),
|
|
|
|
// @Param: 2SRV_IMAX
|
|
// @DisplayName: Integrator limit
|
|
// @Description: Limit of roll integrator gain in centi-degrees of servo travel. Servos are assumed to have +/- 4500 centi-degrees of travel, so a value of 3000 allows trim of up to 2/3 of servo travel range.
|
|
// @Range: 0 4500
|
|
// @Increment: 1
|
|
// @User: Advanced
|
|
AP_GROUPINFO("2SRV_IMAX", 5, AP_RollController, gains.imax, 3000),
|
|
|
|
// @Param: 2SRV_FF
|
|
// @DisplayName: Feed forward Gain
|
|
// @Description: Gain from demanded rate to aileron output.
|
|
// @Range: 0.1 4.0
|
|
// @Increment: 0.1
|
|
// @User: Standard
|
|
AP_GROUPINFO("2SRV_FF", 6, AP_RollController, gains.FF, 0.0f),
|
|
|
|
// @Param: 2SRV_SRMAX
|
|
// @DisplayName: Servo slew rate limit
|
|
// @Description: Sets an upper limit on the servo slew rate produced by the D-gain (roll rate feedback). If the amplitude of the control action produced by the roll rate feedback exceeds this value, then the D-gain is reduced to respect the limit. This limits the amplitude of high frequency oscillations caused by an excessive D-gain. The parameter should be set to no more than 25% of the servo's specified slew rate to allow for inertia and aerodynamic load effects. Note: The D-gain will not be reduced to less than 10% of the nominal value. A valule of zero will disable this feature.
|
|
// @Units: deg/s
|
|
// @Range: 0 500
|
|
// @Increment: 10.0
|
|
// @User: Advanced
|
|
AP_GROUPINFO("2SRV_SRMAX", 7, AP_RollController, _slew_rate_max, 150.0f),
|
|
|
|
// @Param: 2SRV_SRTAU
|
|
// @DisplayName: Servo slew rate decay time constant
|
|
// @Description: This sets the time constant used to recover the D-gain after it has been reduced due to excessive servo slew rate.
|
|
// @Units: s
|
|
// @Range: 0.5 5.0
|
|
// @Increment: 0.1
|
|
// @User: Advanced
|
|
AP_GROUPINFO("2SRV_SRTAU", 8, AP_RollController, _slew_rate_tau, 1.0f),
|
|
|
|
// @Param: _RATE_P
|
|
// @DisplayName: Roll axis rate controller P gain
|
|
// @Description: Roll axis rate controller P gain. Converts the difference between desired roll rate and actual roll rate into a motor speed output
|
|
// @Range: 0.08 0.35
|
|
// @Increment: 0.005
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_I
|
|
// @DisplayName: Roll axis rate controller I gain
|
|
// @Description: Roll axis rate controller I gain. Corrects long-term difference in desired roll rate vs actual roll rate
|
|
// @Range: 0.01 0.6
|
|
// @Increment: 0.01
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_IMAX
|
|
// @DisplayName: Roll axis rate controller I gain maximum
|
|
// @Description: Roll axis rate controller I gain maximum. Constrains the maximum motor output that the I gain will output
|
|
// @Range: 0 1
|
|
// @Increment: 0.01
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_D
|
|
// @DisplayName: Roll axis rate controller D gain
|
|
// @Description: Roll axis rate controller D gain. Compensates for short-term change in desired roll rate vs actual roll rate
|
|
// @Range: 0.001 0.03
|
|
// @Increment: 0.001
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_FF
|
|
// @DisplayName: Roll axis rate controller feed forward
|
|
// @Description: Roll axis rate controller feed forward
|
|
// @Range: 0 3.0
|
|
// @Increment: 0.001
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_FLTT
|
|
// @DisplayName: Roll axis rate controller target frequency in Hz
|
|
// @Description: Roll axis rate controller target frequency in Hz
|
|
// @Range: 2 50
|
|
// @Increment: 1
|
|
// @Units: Hz
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_FLTE
|
|
// @DisplayName: Roll axis rate controller error frequency in Hz
|
|
// @Description: Roll axis rate controller error frequency in Hz
|
|
// @Range: 2 50
|
|
// @Increment: 1
|
|
// @Units: Hz
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_FLTD
|
|
// @DisplayName: Roll axis rate controller derivative frequency in Hz
|
|
// @Description: Roll axis rate controller derivative frequency in Hz
|
|
// @Range: 0 50
|
|
// @Increment: 1
|
|
// @Units: Hz
|
|
// @User: Standard
|
|
|
|
// @Param: _RATE_SMAX
|
|
// @DisplayName: Roll slew rate limit
|
|
// @Description: Sets an upper limit on the slew rate produced by the combined P and D gains. If the amplitude of the control action produced by the rate feedback exceeds this value, then the D+P gain is reduced to respect the limit. This limits the amplitude of high frequency oscillations caused by an excessive gain. The limit should be set to no more than 25% of the actuators maximum slew rate to allow for load effects. Note: The gain will not be reduced to less than 10% of the nominal value. A value of zero will disable this feature.
|
|
// @Range: 0 200
|
|
// @Increment: 0.5
|
|
// @User: Advanced
|
|
|
|
// @Param: _RATE_STAU
|
|
// @DisplayName: Roll slew rate decay time constant
|
|
// @Description: This sets the time constant used to recover the P+D gain after it has been reduced due to excessive slew rate.
|
|
// @Units: s
|
|
// @Range: 0.5 5.0
|
|
// @Increment: 0.1
|
|
// @User: Advanced
|
|
|
|
AP_SUBGROUPINFO(rate_pid, "_RATE_", 9, AP_RollController, AC_PID),
|
|
|
|
AP_GROUPEND
|
|
};
|
|
|
|
|
|
/*
|
|
internal rate controller, called by attitude and rate controller
|
|
public functions
|
|
*/
|
|
int32_t AP_RollController::_get_rate_out_old(float desired_rate, float scaler, bool disable_integrator)
|
|
{
|
|
uint32_t tnow = AP_HAL::millis();
|
|
uint32_t dt = tnow - _last_t;
|
|
if (_last_t == 0 || dt > 1000) {
|
|
dt = 0;
|
|
}
|
|
_last_t = tnow;
|
|
|
|
// Calculate equivalent gains so that values for K_P and K_I can be taken across from the old PID law
|
|
// No conversion is required for K_D
|
|
float ki_rate = gains.I * gains.tau;
|
|
float eas2tas = _ahrs.get_EAS2TAS();
|
|
float kp_ff = MAX((gains.P - gains.I * gains.tau) * gains.tau - gains.D , 0) / eas2tas;
|
|
float k_ff = gains.FF / eas2tas;
|
|
float delta_time = (float)dt * 0.001f;
|
|
// Get body rate vector (radians/sec)
|
|
float omega_x = _ahrs.get_gyro().x;
|
|
|
|
// Calculate the roll rate error (deg/sec) and apply gain scaler
|
|
float achieved_rate = ToDeg(omega_x);
|
|
_pid_info.error = desired_rate - achieved_rate;
|
|
float rate_error = _pid_info.error * scaler;
|
|
_pid_info.target = desired_rate;
|
|
_pid_info.actual = achieved_rate;
|
|
|
|
// Get an airspeed estimate - default to zero if none available
|
|
float aspeed;
|
|
if (!_ahrs.airspeed_estimate(aspeed)) {
|
|
aspeed = 0.0f;
|
|
}
|
|
|
|
// 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 * 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);
|
|
} else if (_last_out > 45) {
|
|
// prevent the integrator from decreasing if surface defln demand is below the lower limit
|
|
integrator_delta = MIN(integrator_delta, 0);
|
|
}
|
|
_pid_info.I += integrator_delta;
|
|
}
|
|
} else {
|
|
_pid_info.I = 0;
|
|
}
|
|
|
|
// Scale the integration limit
|
|
float intLimScaled = gains.imax * 0.01f;
|
|
|
|
// Constrain the integrator state
|
|
_pid_info.I = constrain_float(_pid_info.I, -intLimScaled, intLimScaled);
|
|
|
|
// Calculate the demanded control surface deflection
|
|
// 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.
|
|
const float last_pid_info_D = _pid_info.D;
|
|
|
|
_pid_info.D = rate_error * gains.D * scaler;
|
|
_pid_info.P = desired_rate * kp_ff * scaler;
|
|
_pid_info.FF = desired_rate * k_ff * scaler;
|
|
|
|
if (dt > 0 && _slew_rate_max > 0) {
|
|
// Calculate the slew rate amplitude produced by the unmodified D term
|
|
|
|
// calculate a low pass filtered slew rate
|
|
float Dterm_slew_rate = _slew_rate_filter.apply((fabsf(_pid_info.D - last_pid_info_D)/ delta_time), delta_time);
|
|
|
|
// rectify and apply a decaying envelope filter
|
|
float alpha = 1.0f - constrain_float(delta_time/_slew_rate_tau, 0.0f , 1.0f);
|
|
_slew_rate_amplitude = fmaxf(fabsf(Dterm_slew_rate), alpha * _slew_rate_amplitude);
|
|
_slew_rate_amplitude = fminf(_slew_rate_amplitude, 10.0f*_slew_rate_max);
|
|
|
|
// Calculate and apply the D gain adjustment
|
|
_pid_info.Dmod = _slew_rate_max / fmaxf(_slew_rate_amplitude, _slew_rate_max);
|
|
_pid_info.D *= _pid_info.Dmod;
|
|
}
|
|
|
|
_last_out = _pid_info.D + _pid_info.FF + _pid_info.P;
|
|
|
|
if (autotune.running && aspeed > aparm.airspeed_min) {
|
|
// let autotune have a go at the values
|
|
// Note that we don't pass the integrator component so we get
|
|
// a better idea of how much the base PD controller
|
|
// contributed
|
|
autotune.update(desired_rate, achieved_rate, _last_out);
|
|
}
|
|
|
|
_last_out += _pid_info.I;
|
|
|
|
// Convert to centi-degrees and constrain
|
|
return constrain_float(_last_out * 100, -4500, 4500);
|
|
}
|
|
|
|
/*
|
|
AC_PID based rate controller
|
|
*/
|
|
int32_t AP_RollController::_get_rate_out_ac_pid(float desired_rate, float scaler, bool disable_integrator)
|
|
{
|
|
convert_pid();
|
|
|
|
const float dt = AP::scheduler().get_loop_period_s();
|
|
const float eas2tas = _ahrs.get_EAS2TAS();
|
|
bool limit_I = fabsf(last_ac_out) >= 45;
|
|
float rate_x = _ahrs.get_gyro().x;
|
|
float aspeed;
|
|
float old_I = rate_pid.get_i();
|
|
|
|
rate_pid.set_dt(dt);
|
|
|
|
if (!_ahrs.airspeed_estimate(aspeed)) {
|
|
aspeed = 0;
|
|
}
|
|
bool underspeed = aspeed <= float(aparm.airspeed_min);
|
|
if (underspeed) {
|
|
limit_I = true;
|
|
}
|
|
|
|
// the P and I elements are scaled by sq(scaler). To use an
|
|
// unmodified AC_PID object we scale the inputs and calculate FF separately
|
|
//
|
|
// note that we run AC_PID in radians so that the normal scaling
|
|
// range for IMAX in AC_PID applies (usually an IMAX value less than 1.0)
|
|
rate_pid.update_all(radians(desired_rate) * scaler * scaler, rate_x * scaler * scaler, limit_I);
|
|
|
|
if (underspeed) {
|
|
// when underspeed we lock the integrator
|
|
rate_pid.set_integrator(old_I);
|
|
}
|
|
|
|
// FF should be scaled by scaler/eas2tas, but since we have scaled
|
|
// the AC_PID target above by scaler*scaler we need to instead
|
|
// divide by scaler*eas2tas to get the right scaling
|
|
const float ff = degrees(rate_pid.get_ff() / (scaler * eas2tas));
|
|
|
|
if (disable_integrator) {
|
|
rate_pid.reset_I();
|
|
}
|
|
|
|
// convert AC_PID info object to same scale as old controller
|
|
_pid_info_ac_pid = rate_pid.get_pid_info();
|
|
auto &pinfo = _pid_info_ac_pid;
|
|
|
|
const float deg_scale = degrees(1);
|
|
pinfo.FF = ff;
|
|
pinfo.P *= deg_scale;
|
|
pinfo.I *= deg_scale;
|
|
pinfo.D *= deg_scale;
|
|
|
|
// fix the logged target and actual values to not have the scalers applied
|
|
pinfo.target = desired_rate;
|
|
pinfo.actual = degrees(rate_x);
|
|
|
|
// sum components
|
|
float out = pinfo.FF + pinfo.P + pinfo.I + pinfo.D;
|
|
|
|
// remember the last output to trigger the I limit
|
|
last_ac_out = out;
|
|
|
|
// output is scaled to notional centidegrees of deflection
|
|
return constrain_int32(out * 100, -4500, 4500);
|
|
}
|
|
|
|
|
|
/*
|
|
rate controller selector
|
|
*/
|
|
int32_t AP_RollController::_get_rate_out(float desired_rate, float scaler, bool disable_integrator)
|
|
{
|
|
int32_t ret_ac_pid = _get_rate_out_ac_pid(desired_rate, scaler, disable_integrator);
|
|
int32_t ret_old = _get_rate_out_old(desired_rate, scaler, disable_integrator);
|
|
const auto &pinfo_ac = _pid_info_ac_pid;
|
|
const auto &pinfo_old = _pid_info;
|
|
AP::logger().Write("PIXR", "TimeUS,AC,Old,ACSum,OldSum", "Qiiff",
|
|
AP_HAL::micros64(),
|
|
ret_ac_pid,
|
|
ret_old,
|
|
pinfo_ac.FF + pinfo_ac.P + pinfo_ac.I + pinfo_ac.D,
|
|
pinfo_old.FF + pinfo_old.P + pinfo_old.I + pinfo_old.D);
|
|
return use_ac_pid ? ret_ac_pid : ret_old;
|
|
}
|
|
|
|
/*
|
|
Function returns an equivalent elevator deflection in centi-degrees in the range from -4500 to 4500
|
|
A positive demand is up
|
|
Inputs are:
|
|
1) desired roll rate in degrees/sec
|
|
2) control gain scaler = scaling_speed / aspeed
|
|
*/
|
|
int32_t AP_RollController::get_rate_out(float desired_rate, float scaler)
|
|
{
|
|
return _get_rate_out(desired_rate, scaler, false);
|
|
}
|
|
|
|
/*
|
|
Function returns an equivalent aileron deflection in centi-degrees in the range from -4500 to 4500
|
|
A positive demand is up
|
|
Inputs are:
|
|
1) demanded bank angle in centi-degrees
|
|
2) control gain scaler = scaling_speed / aspeed
|
|
3) boolean which is true when stabilise mode is active
|
|
4) minimum FBW airspeed (metres/sec)
|
|
*/
|
|
int32_t AP_RollController::get_servo_out(int32_t angle_err, float scaler, bool disable_integrator)
|
|
{
|
|
if (gains.tau < 0.1f) {
|
|
gains.tau.set(0.1f);
|
|
}
|
|
|
|
// Calculate the desired roll rate (deg/sec) from the angle error
|
|
float desired_rate = angle_err * 0.01f / gains.tau;
|
|
|
|
// Limit the demanded roll rate
|
|
if (gains.rmax && desired_rate < -gains.rmax) {
|
|
desired_rate = - gains.rmax;
|
|
} else if (gains.rmax && desired_rate > gains.rmax) {
|
|
desired_rate = gains.rmax;
|
|
}
|
|
|
|
return _get_rate_out(desired_rate, scaler, disable_integrator);
|
|
}
|
|
|
|
void AP_RollController::reset_I()
|
|
{
|
|
_pid_info.I = 0;
|
|
rate_pid.reset_I();
|
|
}
|
|
|
|
/*
|
|
convert from old to new PIDs
|
|
this is a temporary conversion function during development
|
|
*/
|
|
void AP_RollController::convert_pid()
|
|
{
|
|
if (done_init && is_positive(rate_pid.ff())) {
|
|
return;
|
|
}
|
|
done_init = true;
|
|
AP_Float &ff = rate_pid.ff();
|
|
if (is_positive(ff) && ff.configured_in_storage()) {
|
|
return;
|
|
}
|
|
const float kp_ff = MAX((gains.P - gains.I * gains.tau) * gains.tau - gains.D, 0);
|
|
rate_pid.ff().set_and_save(gains.FF + kp_ff);
|
|
rate_pid.kI().set_and_save_ifchanged(gains.I * gains.tau);
|
|
rate_pid.kP().set_and_save_ifchanged(gains.D);
|
|
rate_pid.kD().set_and_save_ifchanged(0);
|
|
rate_pid.kIMAX().set_and_save_ifchanged(gains.imax/4500.0);
|
|
}
|