ardupilot/libraries/SITL/SIM_Balloon.cpp

80 lines
2.1 KiB
C++

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
balloon simulator class
*/
#include "SIM_Balloon.h"
#include <stdio.h>
namespace SITL {
Balloon::Balloon(const char *home_str, const char *frame_str) :
Aircraft(home_str, frame_str)
{
mass = 5.0f;
}
/*
update the balloon simulation by one time step
*/
void Balloon::update(const struct sitl_input &input)
{
// get wind vector setup
update_wind(input);
if (!released && input.servos[6] > 1800) {
::printf("Balloon released\n");
released = true;
}
if (!burst && input.servos[7] > 1800) {
::printf("Balloon burst\n");
burst = true;
}
// rotational air resistance
Vector3f rot_accel = -gyro * radians(400) / terminal_rotation_rate;
// air resistance
Vector3f air_resistance = -velocity_air_ef * (GRAVITY_MSS/terminal_velocity);
float lift_accel = 0;
if (!burst && released) {
float air_resistance_at_climb_rate = climb_rate * (GRAVITY_MSS/terminal_velocity);
lift_accel = air_resistance_at_climb_rate + GRAVITY_MSS * dcm.c.z;
}
accel_body = Vector3f(0, 0, -lift_accel);
accel_body += dcm.transposed() * air_resistance;
update_dynamics(rot_accel);
if (position.z < -burst_altitude) {
::printf("Balloon burst at %.1f\n", -position.z);
burst = true;
}
// update lat/lon/altitude
update_position();
// update magnetic field
update_mag_field_bf();
}
} // namespace SITL