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