mirror of https://github.com/ArduPilot/ardupilot
338 lines
11 KiB
C++
338 lines
11 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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// Code by Jon Challinger
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// Modified by Paul Riseborough
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//
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#include <AP_HAL/AP_HAL.h>
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#include "AP_RollController.h"
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#include <AP_AHRS/AP_AHRS.h>
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#include <AP_Scheduler/AP_Scheduler.h>
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#include <GCS_MAVLink/GCS.h>
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extern const AP_HAL::HAL& hal;
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const AP_Param::GroupInfo AP_RollController::var_info[] = {
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// @Param: 2SRV_TCONST
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// @DisplayName: Roll Time Constant
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// @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.
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// @Range: 0.4 1.0
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// @Units: s
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// @Increment: 0.1
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// @User: Advanced
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AP_GROUPINFO("2SRV_TCONST", 0, AP_RollController, gains.tau, 0.5f),
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// index 1 to 3 reserved for old PID values
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// @Param: 2SRV_RMAX
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// @DisplayName: Maximum Roll Rate
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// @Description: This sets the maximum roll rate that the attitude controller will demand (degrees/sec) in angle stabilized modes. Setting it to zero disables this limit.
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// @Range: 0 180
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// @Units: deg/s
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// @Increment: 1
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// @User: Advanced
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AP_GROUPINFO("2SRV_RMAX", 4, AP_RollController, gains.rmax_pos, 0),
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// index 5, 6 reserved for old IMAX, FF
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// @Param: _RATE_P
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// @DisplayName: Roll axis rate controller P gain
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// @Description: Roll axis rate controller P gain. Corrects in proportion to the difference between the desired roll rate vs actual roll rate
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// @Range: 0.08 0.35
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// @Increment: 0.005
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// @User: Standard
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// @Param: _RATE_I
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// @DisplayName: Roll axis rate controller I gain
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// @Description: Roll axis rate controller I gain. Corrects long-term difference in desired roll rate vs actual roll rate
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// @Range: 0.01 0.6
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// @Increment: 0.01
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// @User: Standard
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// @Param: _RATE_IMAX
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// @DisplayName: Roll axis rate controller I gain maximum
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// @Description: Roll axis rate controller I gain maximum. Constrains the maximum that the I term will output
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// @Range: 0 1
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// @Increment: 0.01
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// @User: Standard
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// @Param: _RATE_D
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// @DisplayName: Roll axis rate controller D gain
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// @Description: Roll axis rate controller D gain. Compensates for short-term change in desired roll rate vs actual roll rate
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// @Range: 0.001 0.03
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// @Increment: 0.001
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// @User: Standard
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// @Param: _RATE_FF
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// @DisplayName: Roll axis rate controller feed forward
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// @Description: Roll axis rate controller feed forward
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// @Range: 0 3.0
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// @Increment: 0.001
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// @User: Standard
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// @Param: _RATE_FLTT
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// @DisplayName: Roll axis rate controller target frequency in Hz
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// @Description: Roll axis rate controller target frequency in Hz
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// @Range: 2 50
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// @Increment: 1
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// @Units: Hz
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// @User: Standard
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// @Param: _RATE_FLTE
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// @DisplayName: Roll axis rate controller error frequency in Hz
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// @Description: Roll axis rate controller error frequency in Hz
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// @Range: 2 50
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// @Increment: 1
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// @Units: Hz
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// @User: Standard
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// @Param: _RATE_FLTD
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// @DisplayName: Roll axis rate controller derivative frequency in Hz
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// @Description: Roll axis rate controller derivative frequency in Hz
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// @Range: 0 50
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// @Increment: 1
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// @Units: Hz
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// @User: Standard
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// @Param: _RATE_SMAX
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// @DisplayName: Roll slew rate limit
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// @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.
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// @Range: 0 200
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// @Increment: 0.5
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// @User: Advanced
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// @Param: _RATE_PDMX
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// @DisplayName: Roll axis rate controller PD sum maximum
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// @Description: Roll axis rate controller PD sum maximum. The maximum/minimum value that the sum of the P and D term can output
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// @Range: 0 1
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// @Increment: 0.01
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// @Param: _RATE_D_FF
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// @DisplayName: Roll Derivative FeedForward Gain
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// @Description: FF D Gain which produces an output that is proportional to the rate of change of the target
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// @Range: 0 0.03
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// @Increment: 0.001
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// @User: Advanced
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// @Param: _RATE_NTF
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// @DisplayName: Roll Target notch filter index
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// @Description: Roll Target notch filter index
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// @Range: 1 8
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// @User: Advanced
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// @Param: _RATE_NEF
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// @DisplayName: Roll Error notch filter index
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// @Description: Roll Error notch filter index
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// @Range: 1 8
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// @User: Advanced
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AP_SUBGROUPINFO(rate_pid, "_RATE_", 9, AP_RollController, AC_PID),
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AP_GROUPEND
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};
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// constructor
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AP_RollController::AP_RollController(const AP_FixedWing &parms)
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: aparm(parms)
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{
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AP_Param::setup_object_defaults(this, var_info);
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rate_pid.set_slew_limit_scale(45);
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}
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/*
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AC_PID based rate controller
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*/
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float AP_RollController::_get_rate_out(float desired_rate, float scaler, bool disable_integrator, bool ground_mode)
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{
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const AP_AHRS &_ahrs = AP::ahrs();
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const float dt = AP::scheduler().get_loop_period_s();
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const float eas2tas = _ahrs.get_EAS2TAS();
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bool limit_I = fabsf(_last_out) >= 45;
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float rate_x = _ahrs.get_gyro().x;
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float aspeed;
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float old_I = rate_pid.get_i();
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if (!_ahrs.airspeed_estimate(aspeed)) {
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aspeed = 0;
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}
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bool underspeed = aspeed <= float(aparm.airspeed_min);
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if (underspeed) {
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limit_I = true;
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}
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// the P and I elements are scaled by sq(scaler). To use an
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// unmodified AC_PID object we scale the inputs and calculate FF separately
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//
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// note that we run AC_PID in radians so that the normal scaling
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// range for IMAX in AC_PID applies (usually an IMAX value less than 1.0)
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rate_pid.update_all(radians(desired_rate) * scaler * scaler, rate_x * scaler * scaler, dt, limit_I);
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if (underspeed) {
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// when underspeed we lock the integrator
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rate_pid.set_integrator(old_I);
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}
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// FF should be scaled by scaler/eas2tas, but since we have scaled
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// the AC_PID target above by scaler*scaler we need to instead
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// divide by scaler*eas2tas to get the right scaling
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const float ff = degrees(ff_scale * rate_pid.get_ff() / (scaler * eas2tas));
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ff_scale = 1.0;
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if (disable_integrator) {
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rate_pid.reset_I();
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}
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// convert AC_PID info object to same scale as old controller
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_pid_info = rate_pid.get_pid_info();
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auto &pinfo = _pid_info;
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const float deg_scale = degrees(1);
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pinfo.FF = ff;
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pinfo.P *= deg_scale;
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pinfo.I *= deg_scale;
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pinfo.D *= deg_scale;
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pinfo.DFF *= deg_scale;
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// fix the logged target and actual values to not have the scalers applied
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pinfo.target = desired_rate;
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pinfo.actual = degrees(rate_x);
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// sum components
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float out = pinfo.FF + pinfo.P + pinfo.I + pinfo.D + pinfo.DFF;
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if (ground_mode) {
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// when on ground suppress D term to prevent oscillations
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out -= pinfo.D + 0.5*pinfo.P;
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}
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// remember the last output to trigger the I limit
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_last_out = out;
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if (autotune != nullptr && autotune->running && aspeed > aparm.airspeed_min) {
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// let autotune have a go at the values
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autotune->update(pinfo, scaler, angle_err_deg);
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}
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// output is scaled to notional centidegrees of deflection
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return constrain_float(out * 100, -4500, 4500);
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}
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/*
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Function returns an equivalent elevator deflection in centi-degrees in the range from -4500 to 4500
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A positive demand is up
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Inputs are:
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1) desired roll rate in degrees/sec
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2) control gain scaler = scaling_speed / aspeed
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*/
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float AP_RollController::get_rate_out(float desired_rate, float scaler)
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{
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return _get_rate_out(desired_rate, scaler, false, false);
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}
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/*
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Function returns an equivalent aileron deflection in centi-degrees in the range from -4500 to 4500
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A positive demand is up
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Inputs are:
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1) demanded bank angle in centi-degrees
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2) control gain scaler = scaling_speed / aspeed
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3) boolean which is true when stabilise mode is active
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4) minimum FBW airspeed (metres/sec)
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*/
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float AP_RollController::get_servo_out(int32_t angle_err, float scaler, bool disable_integrator, bool ground_mode)
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{
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if (gains.tau < 0.05f) {
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gains.tau.set(0.05f);
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}
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// Calculate the desired roll rate (deg/sec) from the angle error
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angle_err_deg = angle_err * 0.01;
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float desired_rate = angle_err_deg/ gains.tau;
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// Limit the demanded roll rate
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if (gains.rmax_pos && desired_rate < -gains.rmax_pos) {
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desired_rate = - gains.rmax_pos;
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} else if (gains.rmax_pos && desired_rate > gains.rmax_pos) {
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desired_rate = gains.rmax_pos;
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}
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return _get_rate_out(desired_rate, scaler, disable_integrator, ground_mode);
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}
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void AP_RollController::reset_I()
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{
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rate_pid.reset_I();
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}
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/*
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convert from old to new PIDs
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this is a temporary conversion function during development
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*/
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void AP_RollController::convert_pid()
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{
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AP_Float &ff = rate_pid.ff();
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if (ff.configured()) {
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return;
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}
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float old_ff=0, old_p=1.0, old_i=0.3, old_d=0.08;
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int16_t old_imax=3000;
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bool have_old = AP_Param::get_param_by_index(this, 1, AP_PARAM_FLOAT, &old_p);
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have_old |= AP_Param::get_param_by_index(this, 3, AP_PARAM_FLOAT, &old_i);
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have_old |= AP_Param::get_param_by_index(this, 2, AP_PARAM_FLOAT, &old_d);
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have_old |= AP_Param::get_param_by_index(this, 6, AP_PARAM_FLOAT, &old_ff);
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have_old |= AP_Param::get_param_by_index(this, 5, AP_PARAM_INT16, &old_imax);
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if (!have_old) {
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// none of the old gains were set
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return;
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}
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const float kp_ff = MAX((old_p - old_i * gains.tau) * gains.tau - old_d, 0);
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rate_pid.ff().set_and_save(old_ff + kp_ff);
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rate_pid.kI().set_and_save_ifchanged(old_i * gains.tau);
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rate_pid.kP().set_and_save_ifchanged(old_d);
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rate_pid.kD().set_and_save_ifchanged(0);
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rate_pid.kIMAX().set_and_save_ifchanged(old_imax/4500.0);
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}
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/*
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start an autotune
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*/
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void AP_RollController::autotune_start(void)
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{
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if (autotune == nullptr) {
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autotune = new AP_AutoTune(gains, AP_AutoTune::AUTOTUNE_ROLL, aparm, rate_pid);
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if (autotune == nullptr) {
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if (!failed_autotune_alloc) {
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GCS_SEND_TEXT(MAV_SEVERITY_ERROR, "AutoTune: failed roll allocation");
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}
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failed_autotune_alloc = true;
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}
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}
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if (autotune != nullptr) {
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autotune->start();
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}
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}
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/*
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restore autotune gains
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*/
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void AP_RollController::autotune_restore(void)
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{
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if (autotune != nullptr) {
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autotune->stop();
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}
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}
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