ardupilot/libraries/SITL/SIM_Submarine.cpp

141 lines
4.4 KiB
C++

/*
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/>.
*/
/*
Submarine simulator class
*/
#include "SIM_Submarine.h"
#include <AP_Motors/AP_Motors.h>
#include "Frame_Vectored.h"
#include <stdio.h>
using namespace SITL;
static Thruster vectored_thrusters[] =
{
Thruster(0, MOT_1_ROLL_FACTOR, MOT_1_PITCH_FACTOR, MOT_1_YAW_FACTOR, MOT_1_THROTTLE_FACTOR, MOT_1_FORWARD_FACTOR, MOT_1_STRAFE_FACTOR),
Thruster(1, MOT_2_ROLL_FACTOR, MOT_2_PITCH_FACTOR, MOT_2_YAW_FACTOR, MOT_2_THROTTLE_FACTOR, MOT_2_FORWARD_FACTOR, MOT_2_STRAFE_FACTOR),
Thruster(2, MOT_3_ROLL_FACTOR, MOT_3_PITCH_FACTOR, MOT_3_YAW_FACTOR, MOT_3_THROTTLE_FACTOR, MOT_3_FORWARD_FACTOR, MOT_3_STRAFE_FACTOR),
Thruster(3, MOT_4_ROLL_FACTOR, MOT_4_PITCH_FACTOR, MOT_4_YAW_FACTOR, MOT_4_THROTTLE_FACTOR, MOT_4_FORWARD_FACTOR, MOT_4_STRAFE_FACTOR),
Thruster(4, MOT_5_ROLL_FACTOR, MOT_5_PITCH_FACTOR, MOT_5_YAW_FACTOR, MOT_5_THROTTLE_FACTOR, MOT_5_FORWARD_FACTOR, MOT_5_STRAFE_FACTOR),
Thruster(5, MOT_6_ROLL_FACTOR, MOT_6_PITCH_FACTOR, MOT_6_YAW_FACTOR, MOT_6_THROTTLE_FACTOR, MOT_6_FORWARD_FACTOR, MOT_6_STRAFE_FACTOR)
};
Submarine::Submarine(const char *home_str, const char *frame_str) :
Aircraft(home_str, frame_str),
frame(NULL)
{
frame_height = 0.0;
ground_behavior = GROUND_BEHAVIOR_NONE;
}
// calculate rotational and linear accelerations
void Submarine::calculate_forces(const struct sitl_input &input, Vector3f &rot_accel, Vector3f &body_accel)
{
rot_accel = Vector3f(0,0,0);
// slight positive buoyancy
body_accel = Vector3f(0, 0, -calculate_buoyancy_acceleration());
for (int i = 0; i < 6; i++) {
Thruster t = vectored_thrusters[i];
int16_t pwm = input.servos[t.servo];
float output = 0;
if (pwm < 2000 && pwm > 1000) {
output = (pwm - 1500) / 400.0; // range -1~1
}
// 2.5 scalar for approximate real-life performance of T200 thruster
body_accel += t.linear * output * 2.5;
rot_accel += t.rotational * output;
}
// Limit movement at the sea floor
if (position.z > 100 && body_accel.z > -GRAVITY_MSS) {
body_accel.z = -GRAVITY_MSS;
}
float terminal_rotation_rate = 10.0;
if (terminal_rotation_rate > 0) {
// rotational air resistance
rot_accel.x -= gyro.x * radians(400.0) / terminal_rotation_rate;
rot_accel.y -= gyro.y * radians(400.0) / terminal_rotation_rate;
rot_accel.z -= gyro.z * radians(400.0) / terminal_rotation_rate;
}
float terminal_velocity = 3.0;
if (terminal_velocity > 0) {
// air resistance
Vector3f air_resistance = -velocity_air_ef * (GRAVITY_MSS/terminal_velocity);
body_accel += dcm.transposed() * air_resistance;
}
}
/**
* @brief Calculate buoyancy force of the frame
*
* @return float
*/
float Submarine::calculate_buoyancy_acceleration()
{
float below_water_level = position.z - frame_proprietary.height/2;
// Completely above water level
if (below_water_level < 0) {
return 0.0f;
}
// Completely below water level
if (below_water_level > frame_proprietary.height/2) {
return frame_proprietary.bouyancy_acceleration;
}
// bouyant force is proportional to fraction of height in water
return frame_proprietary.bouyancy_acceleration * below_water_level/frame_proprietary.height;
};
/*
update the Submarine simulation by one time step
*/
void Submarine::update(const struct sitl_input &input)
{
// get wind vector setup
update_wind(input);
Vector3f rot_accel;
calculate_forces(input, rot_accel, accel_body);
update_dynamics(rot_accel);
// update lat/lon/altitude
update_position();
time_advance();
// update magnetic field
update_mag_field_bf();
}
/*
return true if we are on the ground
*/
bool Submarine::on_ground() const
{
return false;
}