mirror of https://github.com/ArduPilot/ardupilot
108 lines
3.4 KiB
C++
108 lines
3.4 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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singlecopter simulator class
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*/
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#include "SIM_SingleCopter.h"
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#include <stdio.h>
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using namespace SITL;
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SingleCopter::SingleCopter(const char *home_str, const char *frame_str) :
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Aircraft(home_str, frame_str)
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{
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mass = 2.0f;
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if (strstr(frame_str, "coax")) {
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frame_type = FRAME_COAX;
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} else {
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frame_type = FRAME_SINGLE;
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}
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/*
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scaling from motor power to Newtons. Allows the copter
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to hover against gravity when the motor is at hover_throttle
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*/
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thrust_scale = (mass * GRAVITY_MSS) / hover_throttle;
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frame_height = 0.1;
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}
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/*
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update the copter simulation by one time step
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*/
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void SingleCopter::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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float actuator[4];
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for (uint8_t i=0; i<4; i++) {
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actuator[i] = constrain_float((input.servos[i]-1500) / 500.0f, -1, 1);
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}
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float thrust;
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float yaw_thrust;
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float roll_thrust;
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float pitch_thrust;
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switch (frame_type) {
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case FRAME_SINGLE:
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thrust = constrain_float((input.servos[4]-1000) / 1000.0f, 0, 1);
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yaw_thrust = -(actuator[0] + actuator[1] + actuator[2] + actuator[3]) * 0.25f * thrust + thrust * rotor_rot_accel;
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roll_thrust = (actuator[0] - actuator[2]) * 0.5f * thrust;
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pitch_thrust = (actuator[1] - actuator[3]) * 0.5f * thrust;
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break;
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case FRAME_COAX:
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default: {
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float motor1 = constrain_float((input.servos[4]-1000) / 1000.0f, 0, 1);
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float motor2 = constrain_float((input.servos[5]-1000) / 1000.0f, 0, 1);
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thrust = 0.5f*(motor1 + motor2);
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yaw_thrust = -(actuator[0] + actuator[1] + actuator[2] + actuator[3]) * 0.25f * thrust + (motor2 - motor1) * rotor_rot_accel;
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roll_thrust = (actuator[0] - actuator[2]) * 0.5f * thrust;
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pitch_thrust = (actuator[1] - actuator[3]) * 0.5f * thrust;
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break;
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}
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}
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// rotational acceleration, in rad/s/s, in body frame
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Vector3f rot_accel(roll_thrust * roll_rate_max,
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pitch_thrust * pitch_rate_max,
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yaw_thrust * yaw_rate_max);
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// rotational air resistance
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rot_accel.x -= gyro.x * radians(5000.0) / terminal_rotation_rate;
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rot_accel.y -= gyro.y * radians(5000.0) / terminal_rotation_rate;
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rot_accel.z -= gyro.z * radians(400.0) / 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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// scale thrust to newtons
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thrust *= thrust_scale;
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accel_body = Vector3f(0, 0, -thrust / mass);
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accel_body += dcm.transposed() * air_resistance;
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update_dynamics(rot_accel);
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// update lat/lon/altitude
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update_position();
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// update magnetic field
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update_mag_field_bf();
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}
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