mirror of https://github.com/ArduPilot/ardupilot
219 lines
7.8 KiB
C++
219 lines
7.8 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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/*
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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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multicopter simulator class
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*/
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#include "SIM_Multicopter.h"
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#include <AP_Motors/AP_Motors.h>
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#include <stdio.h>
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using namespace SITL;
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static const Motor quad_plus_motors[] =
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{
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Motor(AP_MOTORS_MOT_1, 90, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 2),
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Motor(AP_MOTORS_MOT_2, -90, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 4),
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Motor(AP_MOTORS_MOT_3, 0, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 1),
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Motor(AP_MOTORS_MOT_4, 180, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 3),
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};
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static const Motor quad_x_motors[] =
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{
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Motor(AP_MOTORS_MOT_1, 45, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 1),
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Motor(AP_MOTORS_MOT_2, -135, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 3),
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Motor(AP_MOTORS_MOT_3, -45, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 4),
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Motor(AP_MOTORS_MOT_4, 135, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 2),
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};
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static const Motor hexa_motors[] =
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{
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Motor(AP_MOTORS_MOT_1, 0, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 1),
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Motor(AP_MOTORS_MOT_2, 180, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 4),
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Motor(AP_MOTORS_MOT_3,-120, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 5),
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Motor(AP_MOTORS_MOT_4, 60, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 2),
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Motor(AP_MOTORS_MOT_5, -60, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 6),
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Motor(AP_MOTORS_MOT_6, 120, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 3)
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};
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static const Motor hexax_motors[] =
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{
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Motor(AP_MOTORS_MOT_1, 90, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 2),
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Motor(AP_MOTORS_MOT_2, -90, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 5),
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Motor(AP_MOTORS_MOT_3, -30, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 6),
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Motor(AP_MOTORS_MOT_4, 150, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 3),
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Motor(AP_MOTORS_MOT_5, 30, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 1),
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Motor(AP_MOTORS_MOT_6,-150, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 4)
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};
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static const Motor octa_motors[] =
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{
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Motor(AP_MOTORS_MOT_1, 0, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 1),
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Motor(AP_MOTORS_MOT_2, 180, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 5),
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Motor(AP_MOTORS_MOT_3, 45, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 2),
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Motor(AP_MOTORS_MOT_4, 135, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 4),
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Motor(AP_MOTORS_MOT_5, -45, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 8),
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Motor(AP_MOTORS_MOT_6, -135, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 6),
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Motor(AP_MOTORS_MOT_7, -90, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 7),
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Motor(AP_MOTORS_MOT_8, 90, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 3)
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};
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static const Motor octa_quad_motors[] =
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{
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Motor(AP_MOTORS_MOT_1, 45, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 1),
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Motor(AP_MOTORS_MOT_2, -45, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 7),
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Motor(AP_MOTORS_MOT_3, -135, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 5),
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Motor(AP_MOTORS_MOT_4, 135, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 3),
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Motor(AP_MOTORS_MOT_5, -45, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 8),
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Motor(AP_MOTORS_MOT_6, 45, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 2),
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Motor(AP_MOTORS_MOT_7, 135, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 4),
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Motor(AP_MOTORS_MOT_8, -135, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 6)
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};
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/*
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table of supported frame types
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*/
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static Frame supported_frames[] =
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{
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Frame("+", 4, quad_plus_motors),
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Frame("quad", 4, quad_plus_motors),
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Frame("copter", 4, quad_plus_motors),
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Frame("x", 4, quad_x_motors),
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Frame("hexa", 6, hexa_motors),
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Frame("hexax", 6, hexax_motors),
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Frame("octa", 8, octa_motors),
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Frame("octa-quad", 8, octa_quad_motors)
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};
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void Frame::init(float _mass, float hover_throttle, float _terminal_velocity, float _terminal_rotation_rate)
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{
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mass = _mass;
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/*
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scaling from total motor power to Newtons. Allows the copter
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to hover against gravity when each motor is at hover_throttle
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*/
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thrust_scale = (mass * GRAVITY_MSS) / (num_motors * hover_throttle);
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terminal_velocity = _terminal_velocity;
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terminal_rotation_rate = _terminal_rotation_rate;
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}
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/*
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find a frame by name
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*/
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Frame *Frame::find_frame(const char *name)
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{
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for (uint8_t i=0; i < ARRAY_SIZE(supported_frames); i++) {
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if (strcasecmp(name, supported_frames[i].name) == 0) {
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return &supported_frames[i];
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}
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}
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return NULL;
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}
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MultiCopter::MultiCopter(const char *home_str, const char *frame_str) :
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Aircraft(home_str, frame_str),
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frame(NULL)
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{
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frame = Frame::find_frame(frame_str);
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if (frame == NULL) {
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printf("Frame '%s' not found", frame_str);
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exit(1);
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}
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frame->init(1.5, 0.51, 15, 4*radians(360));
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frame_height = 0.1;
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}
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// calculate rotational and linear accelerations
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void Frame::calculate_forces(const Aircraft &aircraft,
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const Aircraft::sitl_input &input,
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Vector3f &rot_accel,
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Vector3f &body_accel)
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{
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// rotational acceleration, in rad/s/s, in body frame
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float thrust = 0.0f; // newtons
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for (uint8_t i=0; i<num_motors; i++) {
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float motor_speed = constrain_float((input.servos[motor_offset+motors[i].servo]-1000)/1000.0, 0, 1);
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rot_accel.x += -radians(5000.0) * sinf(radians(motors[i].angle)) * motor_speed;
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rot_accel.y += radians(5000.0) * cosf(radians(motors[i].angle)) * motor_speed;
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rot_accel.z += motors[i].yaw_factor * motor_speed * radians(400.0);
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thrust += motor_speed * thrust_scale; // newtons
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}
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body_accel = Vector3f(0, 0, -thrust / mass);
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if (terminal_rotation_rate > 0) {
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// rotational air resistance
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const Vector3f &gyro = aircraft.get_gyro();
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rot_accel.x -= gyro.x * radians(400.0) / terminal_rotation_rate;
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rot_accel.y -= gyro.y * radians(400.0) / terminal_rotation_rate;
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rot_accel.z -= gyro.z * radians(400.0) / terminal_rotation_rate;
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}
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if (terminal_velocity > 0) {
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// air resistance
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Vector3f air_resistance = -aircraft.get_velocity_ef() * (GRAVITY_MSS/terminal_velocity);
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body_accel += aircraft.get_dcm().transposed() * air_resistance;
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}
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// add some noise
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const float gyro_noise = radians(0.1);
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const float accel_noise = 0.3;
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const float noise_scale = thrust / (thrust_scale * num_motors);
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rot_accel += Vector3f(aircraft.rand_normal(0, 1),
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aircraft.rand_normal(0, 1),
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aircraft.rand_normal(0, 1)) * gyro_noise * noise_scale;
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body_accel += Vector3f(aircraft.rand_normal(0, 1),
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aircraft.rand_normal(0, 1),
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aircraft.rand_normal(0, 1)) * accel_noise * noise_scale;
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}
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// calculate rotational and linear accelerations
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void MultiCopter::calculate_forces(const struct sitl_input &input, Vector3f &rot_accel, Vector3f &body_accel)
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{
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frame->calculate_forces(*this, input, rot_accel, body_accel);
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}
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/*
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update the multicopter simulation by one time step
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*/
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void MultiCopter::update(const struct sitl_input &input)
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{
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// how much time has passed?
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Vector3f rot_accel;
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calculate_forces(input, rot_accel, accel_body);
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update_dynamics(rot_accel);
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if (on_ground(position)) {
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// zero roll/pitch, but keep yaw
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float r, p, y;
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dcm.to_euler(&r, &p, &y);
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dcm.from_euler(0, 0, y);
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position.z = -(ground_level + frame_height - home.alt*0.01f);
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}
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// update lat/lon/altitude
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update_position();
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}
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