ardupilot/libraries/AC_CustomControl/AC_CustomControl_PID.cpp

#include "AC_CustomControl_PID.h"

#if CUSTOMCONTROL_PID_ENABLED

// table of user settable parameters
const AP_Param::GroupInfo AC_CustomControl_PID::var_info[] = {
    // @Param: ANG_RLL_P
    // @DisplayName: Roll axis angle controller P gain
    // @Description: Roll axis angle controller P gain.  Converts the error between the desired roll angle and actual angle to a desired roll rate
    // @Range: 3.000 12.000
    // @Range{Sub}: 0.0 12.000
    // @User: Standard
    AP_SUBGROUPINFO(_p_angle_roll2, "ANG_RLL_", 1, AC_CustomControl_PID, AC_P),

    // @Param: ANG_PIT_P
    // @DisplayName: Pitch axis angle controller P gain
    // @Description: Pitch axis angle controller P gain.  Converts the error between the desired pitch angle and actual angle to a desired pitch rate
    // @Range: 3.000 12.000
    // @Range{Sub}: 0.0 12.000
    // @User: Standard
    AP_SUBGROUPINFO(_p_angle_pitch2, "ANG_PIT_", 2, AC_CustomControl_PID, AC_P),

    // @Param: ANG_YAW_P
    // @DisplayName: Yaw axis angle controller P gain
    // @Description: Yaw axis angle controller P gain.  Converts the error between the desired yaw angle and actual angle to a desired yaw rate
    // @Range: 3.000 12.000
    // @Range{Sub}: 0.0 6.000
    // @User: Standard    
    AP_SUBGROUPINFO(_p_angle_yaw2, "ANG_YAW_", 3, AC_CustomControl_PID, AC_P),


    // @Param: RAT_RLL_P
    // @DisplayName: Roll axis rate controller P gain
    // @Description: Roll axis rate controller P gain. Corrects in proportion to the difference between the desired roll rate vs actual roll rate
    // @Range: 0.01 0.5
    // @Increment: 0.005
    // @User: Standard

    // @Param: RAT_RLL_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 2.0
    // @Increment: 0.01
    // @User: Standard

    // @Param: RAT_RLL_IMAX
    // @DisplayName: Roll axis rate controller I gain maximum
    // @Description: Roll axis rate controller I gain maximum.  Constrains the maximum that the I term will output
    // @Range: 0 1
    // @Increment: 0.01
    // @User: Standard

    // @Param: RAT_RLL_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: 0.0 0.05
    // @Increment: 0.001
    // @User: Standard

    // @Param: RAT_RLL_FF
    // @DisplayName: Roll axis rate controller feed forward
    // @Description: Roll axis rate controller feed forward
    // @Range: 0 0.5
    // @Increment: 0.001
    // @User: Standard

    // @Param: RAT_RLL_FLTT
    // @DisplayName: Roll axis rate controller target frequency in Hz
    // @Description: Roll axis rate controller target frequency in Hz
    // @Range: 5 100
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_RLL_FLTE
    // @DisplayName: Roll axis rate controller error frequency in Hz
    // @Description: Roll axis rate controller error frequency in Hz
    // @Range: 0 100
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_RLL_FLTD
    // @DisplayName: Roll axis rate controller derivative frequency in Hz
    // @Description: Roll axis rate controller derivative frequency in Hz
    // @Range: 5 100
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_RLL_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
    AP_SUBGROUPINFO(_pid_atti_rate_roll, "RAT_RLL_", 4, AC_CustomControl_PID, AC_PID),

    // @Param: RAT_PIT_P
    // @DisplayName: Pitch axis rate controller P gain
    // @Description: Pitch axis rate controller P gain.  Corrects in proportion to the difference between the desired pitch rate vs actual pitch rate
    // @Range: 0.01 0.50
    // @Increment: 0.005
    // @User: Standard

    // @Param: RAT_PIT_I
    // @DisplayName: Pitch axis rate controller I gain
    // @Description: Pitch axis rate controller I gain.  Corrects long-term difference in desired pitch rate vs actual pitch rate
    // @Range: 0.01 2.0
    // @Increment: 0.01
    // @User: Standard

    // @Param: RAT_PIT_IMAX
    // @DisplayName: Pitch axis rate controller I gain maximum
    // @Description: Pitch axis rate controller I gain maximum.  Constrains the maximum that the I term will output
    // @Range: 0 1
    // @Increment: 0.01
    // @User: Standard

    // @Param: RAT_PIT_D
    // @DisplayName: Pitch axis rate controller D gain
    // @Description: Pitch axis rate controller D gain.  Compensates for short-term change in desired pitch rate vs actual pitch rate
    // @Range: 0.0 0.05
    // @Increment: 0.001
    // @User: Standard

    // @Param: RAT_PIT_FF
    // @DisplayName: Pitch axis rate controller feed forward
    // @Description: Pitch axis rate controller feed forward
    // @Range: 0 0.5
    // @Increment: 0.001
    // @User: Standard

    // @Param: RAT_PIT_FLTT
    // @DisplayName: Pitch axis rate controller target frequency in Hz
    // @Description: Pitch axis rate controller target frequency in Hz
    // @Range: 5 100
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_PIT_FLTE
    // @DisplayName: Pitch axis rate controller error frequency in Hz
    // @Description: Pitch axis rate controller error frequency in Hz
    // @Range: 0 100
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_PIT_FLTD
    // @DisplayName: Pitch axis rate controller derivative frequency in Hz
    // @Description: Pitch axis rate controller derivative frequency in Hz
    // @Range: 5 100
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_PIT_SMAX
    // @DisplayName: Pitch 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
    AP_SUBGROUPINFO(_pid_atti_rate_pitch, "RAT_PIT_", 5, AC_CustomControl_PID, AC_PID),


    // @Param: RAT_YAW_P
    // @DisplayName: Yaw axis rate controller P gain
    // @Description: Yaw axis rate controller P gain.  Corrects in proportion to the difference between the desired yaw rate vs actual yaw rate
    // @Range: 0.10 2.50
    // @Increment: 0.005
    // @User: Standard

    // @Param: RAT_YAW_I
    // @DisplayName: Yaw axis rate controller I gain
    // @Description: Yaw axis rate controller I gain.  Corrects long-term difference in desired yaw rate vs actual yaw rate
    // @Range: 0.010 1.0
    // @Increment: 0.01
    // @User: Standard

    // @Param: RAT_YAW_IMAX
    // @DisplayName: Yaw axis rate controller I gain maximum
    // @Description: Yaw axis rate controller I gain maximum.  Constrains the maximum that the I term will output
    // @Range: 0 1
    // @Increment: 0.01
    // @User: Standard

    // @Param: RAT_YAW_D
    // @DisplayName: Yaw axis rate controller D gain
    // @Description: Yaw axis rate controller D gain.  Compensates for short-term change in desired yaw rate vs actual yaw rate
    // @Range: 0.000 0.02
    // @Increment: 0.001
    // @User: Standard

    // @Param: RAT_YAW_FF
    // @DisplayName: Yaw axis rate controller feed forward
    // @Description: Yaw axis rate controller feed forward
    // @Range: 0 0.5
    // @Increment: 0.001
    // @User: Standard

    // @Param: RAT_YAW_FLTT
    // @DisplayName: Yaw axis rate controller target frequency in Hz
    // @Description: Yaw axis rate controller target frequency in Hz
    // @Range: 1 50
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_YAW_FLTE
    // @DisplayName: Yaw axis rate controller error frequency in Hz
    // @Description: Yaw axis rate controller error frequency in Hz
    // @Range: 0 20
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_YAW_FLTD
    // @DisplayName: Yaw axis rate controller derivative frequency in Hz
    // @Description: Yaw axis rate controller derivative frequency in Hz
    // @Range: 5 50
    // @Increment: 1
    // @Units: Hz
    // @User: Standard

    // @Param: RAT_YAW_SMAX
    // @DisplayName: Yaw 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
    AP_SUBGROUPINFO(_pid_atti_rate_yaw, "RAT_YAW_", 6, AC_CustomControl_PID, AC_PID),

    AP_GROUPEND
};

AC_CustomControl_PID::AC_CustomControl_PID(AC_CustomControl& frontend, AP_AHRS_View*& ahrs, AC_AttitudeControl_Multi*& att_control, AP_MotorsMulticopter*& motors, float dt) :
    AC_CustomControl_Backend(frontend, ahrs, att_control, motors, dt),
    _p_angle_roll2(AC_ATTITUDE_CONTROL_ANGLE_P * 0.90f),
    _p_angle_pitch2(AC_ATTITUDE_CONTROL_ANGLE_P * 0.90f),
    _p_angle_yaw2(AC_ATTITUDE_CONTROL_ANGLE_P * 0.90f),
    _pid_atti_rate_roll(AC_ATC_MULTI_RATE_RP_P * 0.90f, AC_ATC_MULTI_RATE_RP_I * 0.90f, AC_ATC_MULTI_RATE_RP_D * 0.90f, 0.0f, AC_ATC_MULTI_RATE_RP_IMAX * 0.90f, AC_ATC_MULTI_RATE_RP_FILT_HZ * 0.90f, 0.0f, AC_ATC_MULTI_RATE_RP_FILT_HZ * 0.90f),
    _pid_atti_rate_pitch(AC_ATC_MULTI_RATE_RP_P * 0.90f, AC_ATC_MULTI_RATE_RP_I * 0.90f, AC_ATC_MULTI_RATE_RP_D * 0.90f, 0.0f, AC_ATC_MULTI_RATE_RP_IMAX * 0.90f, AC_ATC_MULTI_RATE_RP_FILT_HZ * 0.90f, 0.0f, AC_ATC_MULTI_RATE_RP_FILT_HZ * 0.90f),
    _pid_atti_rate_yaw(AC_ATC_MULTI_RATE_YAW_P * 0.90f, AC_ATC_MULTI_RATE_YAW_I * 0.90f, AC_ATC_MULTI_RATE_YAW_D * 0.90f, 0.0f, AC_ATC_MULTI_RATE_YAW_IMAX * 0.90f, AC_ATC_MULTI_RATE_RP_FILT_HZ * 0.90f, AC_ATC_MULTI_RATE_YAW_FILT_HZ * 0.90f, 0.0f)
{
    _dt = dt;
    AP_Param::setup_object_defaults(this, var_info);
}

Vector3f AC_CustomControl_PID::update()
{
      // reset controller based on spool state
    switch (_motors->get_spool_state()) {
        case AP_Motors::SpoolState::SHUT_DOWN:
        case AP_Motors::SpoolState::GROUND_IDLE:
            // We are still at the ground. Reset custom controller to avoid
            // build up, ex: integrator
            reset();
            break;

        case AP_Motors::SpoolState::THROTTLE_UNLIMITED:
        case AP_Motors::SpoolState::SPOOLING_UP:
        case AP_Motors::SpoolState::SPOOLING_DOWN:
            // we are off the ground
            break;
    }

    // run custom controller after here
     Quaternion attitude_body, attitude_target;
    _ahrs->get_quat_body_to_ned(attitude_body);

    attitude_target = _att_control->get_attitude_target_quat();
    // This vector represents the angular error to rotate the thrust vector using x and y and heading using z
    Vector3f attitude_error;
    float _thrust_angle, _thrust_error_angle;
    _att_control->thrust_heading_rotation_angles(attitude_target, attitude_body, attitude_error, _thrust_angle, _thrust_error_angle);

    // recalculate ang vel feedforward from attitude target model
    // rotation from the target frame to the body frame
    Quaternion rotation_target_to_body = attitude_body.inverse() * attitude_target;
    // target angle velocity vector in the body frame
    Vector3f ang_vel_body_feedforward = rotation_target_to_body * _att_control->get_attitude_target_ang_vel();

    // run attitude controller
    Vector3f target_rate;
    target_rate[0] = _p_angle_roll2.kP() * attitude_error.x + ang_vel_body_feedforward[0];
    target_rate[1] = _p_angle_pitch2.kP() * attitude_error.y + ang_vel_body_feedforward[1];
    target_rate[2] = _p_angle_yaw2.kP() * attitude_error.z + ang_vel_body_feedforward[2];

    // run rate controller
    Vector3f gyro_latest = _ahrs->get_gyro_latest();
    Vector3f motor_out;
    motor_out.x = _pid_atti_rate_roll.update_all(target_rate[0], gyro_latest[0], _dt, false);
    motor_out.y = _pid_atti_rate_pitch.update_all(target_rate[1], gyro_latest[1], _dt, false);
    motor_out.z = _pid_atti_rate_yaw.update_all(target_rate[2], gyro_latest[2], _dt, false);

    return motor_out;
}

// This example uses exact same controller architecture as ArduCopter attitude controller without all the safe guard against saturation.
// The gains are scaled 0.9 times to better detect switch over response. 
// Note that integrator are not reset correctly as it is done in reset_main_att_controller inside AC_CustomControl.cpp
// This is done intentionally to demonstrate switch over performance of two exact controller with different reset handling.
void AC_CustomControl_PID::reset(void)
{
    _pid_atti_rate_roll.reset_I();
    _pid_atti_rate_pitch.reset_I();
    _pid_atti_rate_yaw.reset_I();
    _pid_atti_rate_roll.reset_filter();
    _pid_atti_rate_pitch.reset_filter();
    _pid_atti_rate_yaw.reset_filter();
}

#endif