ardupilot/ArduCopter/heli_control_acro.pde

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#if FRAME_CONFIG == HELI_FRAME
/*
 * heli_control_acro.pde - init and run calls for acro flight mode for trad heli
 */

// heli_acro_init - initialise acro controller
static bool heli_acro_init(bool ignore_checks)
{
    // always successfully enter acro
    return true;
}

// heli_acro_run - runs the acro controller
// should be called at 100hz or more
static void heli_acro_run()
{
    float target_roll, target_pitch, target_yaw;
    
    // Tradheli should not reset roll, pitch, yaw targets when motors are not runup, because
    // we may be in autorotation flight.  These should be reset only when transitioning from disarmed
    // to armed, because the pilot will have placed the helicopter down on the landing pad.  This is so
    // that the servos move in a realistic fashion while disarmed for operational checks.
    // Also, unlike multicopters we do not set throttle (i.e. collective pitch) to zero so the swash servos move
    
    if(!motors.armed()) {
        heli_flags.init_targets_on_arming=true;
        attitude_control.set_yaw_target_to_current_heading();
    }

    if(motors.armed() && heli_flags.init_targets_on_arming) {
        heli_flags.init_targets_on_arming=false;
        attitude_control.relax_bf_rate_controller();
        
    }   

    // To-Do: add support for flybarred helis

    // convert the input to the desired body frame rate
    get_pilot_desired_angle_rates(g.rc_1.control_in, g.rc_2.control_in, g.rc_4.control_in, target_roll, target_pitch, target_yaw);

    // run attitude controller
    attitude_control.rate_bf_roll_pitch_yaw(target_roll, target_pitch, target_yaw);

    // output pilot's throttle without angle boost
    attitude_control.set_throttle_out(g.rc_3.control_in, false);
}

#endif  //HELI_FRAME