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/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file mixer_multirotor.cpp
*
* Multi-rotor mixers.
*/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <math.h>
#include "mixer.h"
#define debug(fmt, args...) do { } while(0)
//#define debug(fmt, args...) do { printf("[mixer] " fmt "\n", ##args); } while(0)
//#include <debug.h>
//#define debug(fmt, args...) lowsyslog(fmt "\n", ##args)
/*
* Clockwise: 1
* Counter-clockwise: -1
*/
namespace
{
/*
* These tables automatically generated by multi_tables - do not edit.
*/
const MultirotorMixer::Rotor _config_quad_x[] = {
{ -0.707107, 0.707107, 1.00 },
{ 0.707107, -0.707107, 1.00 },
{ 0.707107, 0.707107, -1.00 },
{ -0.707107, -0.707107, -1.00 },
};
const MultirotorMixer::Rotor _config_quad_plus[] = {
{ -1.000000, 0.000000, 1.00 },
{ 1.000000, 0.000000, 1.00 },
{ 0.000000, 1.000000, -1.00 },
{ -0.000000, -1.000000, -1.00 },
};
const MultirotorMixer::Rotor _config_quad_v[] = {
{ -0.927184, 0.374607, 1.00 },
{ 0.694658, -0.719340, 1.00 },
{ 0.927184, 0.374607, -1.00 },
{ -0.694658, -0.719340, -1.00 },
};
const MultirotorMixer::Rotor _config_quad_wide[] = {
{ -0.927184, 0.374607, 1.00 },
{ 0.777146, -0.629320, 1.00 },
{ 0.927184, 0.374607, -1.00 },
{ -0.777146, -0.629320, -1.00 },
};
const MultirotorMixer::Rotor _config_hex_x[] = {
{ -1.000000, 0.000000, -1.00 },
{ 1.000000, 0.000000, 1.00 },
{ 0.500000, 0.866025, -1.00 },
{ -0.500000, -0.866025, 1.00 },
{ -0.500000, 0.866025, 1.00 },
{ 0.500000, -0.866025, -1.00 },
};
const MultirotorMixer::Rotor _config_hex_plus[] = {
{ 0.000000, 1.000000, -1.00 },
{ -0.000000, -1.000000, 1.00 },
{ 0.866025, -0.500000, -1.00 },
{ -0.866025, 0.500000, 1.00 },
{ 0.866025, 0.500000, 1.00 },
{ -0.866025, -0.500000, -1.00 },
};
const MultirotorMixer::Rotor _config_octa_x[] = {
{ -0.382683, 0.923880, -1.00 },
{ 0.382683, -0.923880, -1.00 },
{ -0.923880, 0.382683, 1.00 },
{ -0.382683, -0.923880, 1.00 },
{ 0.382683, 0.923880, 1.00 },
{ 0.923880, -0.382683, 1.00 },
{ 0.923880, 0.382683, -1.00 },
{ -0.923880, -0.382683, -1.00 },
};
const MultirotorMixer::Rotor _config_octa_plus[] = {
{ 0.000000, 1.000000, -1.00 },
{ -0.000000, -1.000000, -1.00 },
{ -0.707107, 0.707107, 1.00 },
{ -0.707107, -0.707107, 1.00 },
{ 0.707107, 0.707107, 1.00 },
{ 0.707107, -0.707107, 1.00 },
{ 1.000000, 0.000000, -1.00 },
{ -1.000000, 0.000000, -1.00 },
};
const MultirotorMixer::Rotor *_config_index[MultirotorMixer::Geometry::MAX_GEOMETRY] = {
&_config_quad_x[0],
&_config_quad_plus[0],
&_config_quad_v[0],
&_config_quad_wide[0],
&_config_hex_x[0],
&_config_hex_plus[0],
&_config_octa_x[0],
&_config_octa_plus[0],
};
const unsigned _config_rotor_count[MultirotorMixer::Geometry::MAX_GEOMETRY] = {
4, /* quad_x */
4, /* quad_plus */
4, /* quad_v */
4, /* quad_wide */
6, /* hex_x */
6, /* hex_plus */
8, /* octa_x */
8, /* octa_plus */
};
}
MultirotorMixer::MultirotorMixer(ControlCallback control_cb,
uintptr_t cb_handle,
Geometry geometry,
float roll_scale,
float pitch_scale,
float yaw_scale,
float deadband) :
Mixer(control_cb, cb_handle),
_roll_scale(roll_scale),
_pitch_scale(pitch_scale),
_yaw_scale(yaw_scale),
_deadband(-1.0f + deadband), /* shift to output range here to avoid runtime calculation */
_rotor_count(_config_rotor_count[geometry]),
_rotors(_config_index[geometry])
{
}
MultirotorMixer::~MultirotorMixer()
{
}
MultirotorMixer *
MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handle, const char *buf, unsigned &buflen)
{
MultirotorMixer::Geometry geometry;
char geomname[8];
int s[4];
int used;
if (sscanf(buf, "R: %s %d %d %d %d%n", geomname, &s[0], &s[1], &s[2], &s[3], &used) != 5) {
debug("multirotor parse failed on '%s'", buf);
return nullptr;
}
if (used > (int)buflen) {
debug("multirotor spec used %d of %u", used, buflen);
return nullptr;
}
buflen -= used;
if (!strcmp(geomname, "4+")) {
geometry = MultirotorMixer::QUAD_PLUS;
} else if (!strcmp(geomname, "4x")) {
geometry = MultirotorMixer::QUAD_X;
} else if (!strcmp(geomname, "4v")) {
geometry = MultirotorMixer::QUAD_V;
} else if (!strcmp(geomname, "4w")) {
geometry = MultirotorMixer::QUAD_WIDE;
} else if (!strcmp(geomname, "6+")) {
geometry = MultirotorMixer::HEX_PLUS;
} else if (!strcmp(geomname, "6x")) {
geometry = MultirotorMixer::HEX_X;
} else if (!strcmp(geomname, "8+")) {
geometry = MultirotorMixer::OCTA_PLUS;
} else if (!strcmp(geomname, "8x")) {
geometry = MultirotorMixer::OCTA_X;
} else {
debug("unrecognised geometry '%s'", geomname);
return nullptr;
}
debug("adding multirotor mixer '%s'", geomname);
return new MultirotorMixer(
control_cb,
cb_handle,
geometry,
s[0] / 10000.0f,
s[1] / 10000.0f,
s[2] / 10000.0f,
s[3] / 10000.0f);
}
unsigned
MultirotorMixer::mix(float *outputs, unsigned space)
{
float roll = get_control(0, 0) * _roll_scale;
//lowsyslog("roll: %d, get_control0: %d, %d\n", (int)(roll), (int)(get_control(0, 0)), (int)(_roll_scale));
float pitch = get_control(0, 1) * _pitch_scale;
float yaw = get_control(0, 2) * _yaw_scale;
float thrust = get_control(0, 3);
//lowsyslog("thrust: %d, get_control3: %d\n", (int)(thrust), (int)(get_control(0, 3)));
float max = 0.0f;
float fixup_scale;
/* use an output factor to prevent too strong control signals at low throttle */
float min_thrust = 0.05f;
float max_thrust = 1.0f;
float startpoint_full_control = 0.40f;
float output_factor;
/* keep roll, pitch and yaw control to 0 below min thrust */
if (thrust <= min_thrust) {
output_factor = 0.0f;
/* linearly increase the output factor from 0 to 1 between min_thrust and startpoint_full_control */
} else if (thrust < startpoint_full_control && thrust > min_thrust) {
output_factor = (thrust / max_thrust) / (startpoint_full_control - min_thrust);
/* and then stay at full control */
} else {
output_factor = max_thrust;
}
roll *= output_factor;
pitch *= output_factor;
yaw *= output_factor;
/* perform initial mix pass yielding un-bounded outputs */
for (unsigned i = 0; i < _rotor_count; i++) {
float tmp = roll * _rotors[i].roll_scale +
pitch * _rotors[i].pitch_scale +
yaw * _rotors[i].yaw_scale +
thrust;
if (tmp > max)
max = tmp;
outputs[i] = tmp;
}
/* scale values into the -1.0 - 1.0 range */
if (max > 1.0f) {
fixup_scale = 2.0f / max;
} else {
fixup_scale = 2.0f;
}
for (unsigned i = 0; i < _rotor_count; i++)
outputs[i] = -1.0f + (outputs[i] * fixup_scale);
/* ensure outputs are out of the deadband */
for (unsigned i = 0; i < _rotor_count; i++)
if (outputs[i] < _deadband)
outputs[i] = _deadband;
return _rotor_count;
}
void
MultirotorMixer::groups_required(uint32_t &groups)
{
/* XXX for now, hardcoded to indexes 0-3 in control group zero */
groups |= (1 << 0);
}
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