Line data    Source code

       1             : /*
       2             :    This program is free software: you can redistribute it and/or modify
       3             :    it under the terms of the GNU General Public License as published by
       4             :    the Free Software Foundation, either version 3 of the License, or
       5             :    (at your option) any later version.
       6             : 
       7             :    This program is distributed in the hope that it will be useful,
       8             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
       9             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      10             :    GNU General Public License for more details.
      11             : 
      12             :    You should have received a copy of the GNU General Public License
      13             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.
      14             :  */
      15             : /*
      16             :   balloon simulator class
      17             : */
      18             : 
      19             : #include "SIM_Balloon.h"
      20             : 
      21             : #include <stdio.h>
      22             : 
      23             : namespace SITL {
      24             : 
      25           0 : Balloon::Balloon(const char *frame_str) :
      26           0 :     Aircraft(frame_str)
      27             : {
      28           0 :     mass = 5.0f;
      29           0 : }
      30             : 
      31             : /*
      32             :   update the balloon simulation by one time step
      33             :  */
      34           0 : void Balloon::update(const struct sitl_input &input)
      35             : {
      36             :     // get wind vector setup
      37           0 :     update_wind(input);
      38             : 
      39           0 :     if (!released && input.servos[6] > 1800) {
      40           0 :         ::printf("Balloon released\n");
      41           0 :         released = true;
      42             :     }
      43             : 
      44           0 :     if (!burst && input.servos[7] > 1800) {
      45           0 :         ::printf("Balloon burst\n");
      46           0 :         burst = true;
      47             :     }
      48             : 
      49             :     // rotational air resistance
      50           0 :     Vector3f rot_accel = -gyro * radians(400) / terminal_rotation_rate;
      51             : 
      52             :     // air resistance
      53           0 :     Vector3f air_resistance = -velocity_air_ef * (GRAVITY_MSS/terminal_velocity) / eas2tas;
      54             : 
      55           0 :     float lift_accel = 0;
      56           0 :     if (!burst && released) {
      57           0 :         float air_resistance_at_climb_rate = climb_rate * (GRAVITY_MSS/terminal_velocity);
      58           0 :         lift_accel = air_resistance_at_climb_rate + GRAVITY_MSS * dcm.c.z;
      59             :     }
      60             : 
      61           0 :     accel_body = Vector3f(0, 0, -lift_accel);
      62           0 :     accel_body += dcm.transposed() * air_resistance;
      63             :     
      64           0 :     update_dynamics(rot_accel);
      65             : 
      66           0 :     if (position.z < -burst_altitude) {
      67           0 :         ::printf("Balloon burst at %.1f\n", -position.z);
      68           0 :         burst = true;
      69             :     }
      70             :     
      71             :     // update lat/lon/altitude
      72           0 :     update_position();
      73           0 :     time_advance();
      74             : 
      75             :     // update magnetic field
      76           0 :     update_mag_field_bf();
      77             : 
      78           0 :     update_battery();
      79           0 : }
      80             : 
      81             : } // namespace SITL