ardupilot/ArduCopter/control_althold.cpp

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#include "Copter.h"


/*
 * control_althold.pde - init and run calls for althold, flight mode
 */

// althold_init - initialise althold controller
bool Copter::althold_init(bool ignore_checks)
{
    // initialize vertical speeds and leash lengths
    pos_control.set_speed_z(-g.pilot_velocity_z_max, g.pilot_velocity_z_max);
    pos_control.set_accel_z(g.pilot_accel_z);

    // initialise altitude target to stopping point
    pos_control.set_target_to_stopping_point_z();

    // stop takeoff if running
    takeoff_stop();

    return true;
}

// althold_run - runs the althold controller
// should be called at 100hz or more
void Copter::althold_run()
{
    AltHoldModeState althold_state;
    float takeoff_climb_rate = 0.0f;

    // apply SIMPLE mode transform to pilot inputs
    update_simple_mode();

    // get pilot desired lean angles
    float target_roll, target_pitch;
    get_pilot_desired_lean_angles(channel_roll->control_in, channel_pitch->control_in, target_roll, target_pitch);

    // get pilot's desired yaw rate
    float target_yaw_rate = get_pilot_desired_yaw_rate(channel_yaw->control_in);

    // get pilot desired climb rate
    float target_climb_rate = get_pilot_desired_climb_rate(channel_throttle->control_in);
    target_climb_rate = constrain_float(target_climb_rate, -g.pilot_velocity_z_max, g.pilot_velocity_z_max);

#if FRAME_CONFIG == HELI_FRAME
    // helicopters are held on the ground until rotor speed runup has finished
    bool takeoff_triggered = (ap.land_complete && (channel_throttle->control_in > get_takeoff_trigger_throttle()) && motors.rotor_runup_complete());

    if(!motors.armed()) {
        heli_flags.init_targets_on_arming=true;
        attitude_control.set_yaw_target_to_current_heading();
    }

    // if we have recently armed and rotor is just ramping up speed, relax yaw controller
    if(motors.armed() && heli_flags.init_targets_on_arming) {
        attitude_control.relax_bf_rate_controller();
        attitude_control.set_yaw_target_to_current_heading();
        if (motors.rotor_speed_above_critical()) {
            heli_flags.init_targets_on_arming=false;
        }
    }   
#else
    bool takeoff_triggered = (ap.land_complete && (channel_throttle->control_in > get_takeoff_trigger_throttle()));
#endif

    // Alt Hold State Machine Determination
    if(!ap.auto_armed || !motors.get_interlock()) {
        althold_state = AltHold_Disarmed;
    } else if (takeoff_state.running || takeoff_triggered){
        althold_state = AltHold_Takeoff;
    } else if (ap.land_complete){
        althold_state = AltHold_Landed;
    } else {
        althold_state = AltHold_Flying;
    }

    // Alt Hold State Machine
    switch (althold_state) {

    case AltHold_Disarmed:

#if FRAME_CONFIG == HELI_FRAME  // Helicopters always stabilize roll/pitch/yaw
        // call attitude controller
        attitude_control.angle_ef_roll_pitch_rate_ef_yaw_smooth(target_roll, target_pitch, target_yaw_rate, get_smoothing_gain());
        attitude_control.set_throttle_out(0,false,g.throttle_filt);
#else   // Multirotors do not stabilize roll/pitch/yaw when disarmed
        attitude_control.set_throttle_out_unstabilized(0,true,g.throttle_filt);
#endif  // HELI_FRAME
        pos_control.relax_alt_hold_controllers(get_throttle_pre_takeoff(channel_throttle->control_in)-throttle_average);
        break;

    case AltHold_Takeoff:

        // initiate take-off
        if (!takeoff_state.running) {
            takeoff_timer_start(constrain_float(g.pilot_takeoff_alt,0.0f,1000.0f));
            // indicate we are taking off
            set_land_complete(false);
            // clear i terms
            set_throttle_takeoff();
        }

        // get take-off adjusted pilot and takeoff climb rates
        takeoff_get_climb_rates(target_climb_rate, takeoff_climb_rate);

        // call attitude controller
        attitude_control.angle_ef_roll_pitch_rate_ef_yaw_smooth(target_roll, target_pitch, target_yaw_rate, get_smoothing_gain());

        // call position controller
        pos_control.set_alt_target_from_climb_rate(target_climb_rate, G_Dt, false);
        pos_control.add_takeoff_climb_rate(takeoff_climb_rate, G_Dt);
        pos_control.update_z_controller();
        break;

    case AltHold_Landed:

#if FRAME_CONFIG == HELI_FRAME  // Helicopters always stabilize roll/pitch/yaw
        // call attitude controller
        attitude_control.angle_ef_roll_pitch_rate_ef_yaw_smooth(target_roll, target_pitch, target_yaw_rate, get_smoothing_gain());
        attitude_control.set_throttle_out(get_throttle_pre_takeoff(channel_throttle->control_in),false,g.throttle_filt);
#else   // Multirotors do not stabilize roll/pitch/yaw when disarmed
        attitude_control.set_throttle_out_unstabilized(get_throttle_pre_takeoff(channel_throttle->control_in),true,g.throttle_filt);
#endif
        pos_control.relax_alt_hold_controllers(get_throttle_pre_takeoff(channel_throttle->control_in)-throttle_average);
        break;

    case AltHold_Flying:
        // call attitude controller
        attitude_control.angle_ef_roll_pitch_rate_ef_yaw_smooth(target_roll, target_pitch, target_yaw_rate, get_smoothing_gain());

        // call throttle controller
        if (sonar_enabled && (sonar_alt_health >= SONAR_ALT_HEALTH_MAX)) {
            // if sonar is ok, use surface tracking
            target_climb_rate = get_surface_tracking_climb_rate(target_climb_rate, pos_control.get_alt_target(), G_Dt);
        }

        // call position controller
        pos_control.set_alt_target_from_climb_rate(target_climb_rate, G_Dt, false);
        pos_control.update_z_controller();
        break;
    }
}