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/**
* @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
{
float constrain(float val, float min, float max)
{
return (val < min) ? min : ((val > max) ? max : val);
}
/*
* 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_octa_cox[] = {
{ -0.707107, 0.707107, 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 },
{ -0.707107, 0.707107, -1.00 },
{ -0.707107, -0.707107, 1.00 },
{ 0.707107, -0.707107, -1.00 },
};
const MultirotorMixer::Rotor *_config_index[MultirotorMixer::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],
&_config_octa_cox[0],
};
const unsigned _config_rotor_count[MultirotorMixer::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 */
8, /* octa_cox */
};
}
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;
const char *end = buf + buflen;
/* enforce that the mixer ends with space or a new line */
for (int i = buflen - 1; i >= 0; i--) {
if (buf[i] == '\0')
continue;
/* require a space or newline at the end of the buffer, fail on printable chars */
if (buf[i] == ' ' || buf[i] == '\n' || buf[i] == '\r') {
/* found a line ending or space, so no split symbols / numbers. good. */
break;
} else {
debug("simple parser rejected: No newline / space at end of buf. (#%d/%d: 0x%02x)", i, buflen-1, buf[i]);
return nullptr;
}
}
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("OVERFLOW: multirotor spec used %d of %u", used, buflen);
return nullptr;
}
buf = skipline(buf, buflen);
if (buf == nullptr) {
debug("no line ending, line is incomplete");
return nullptr;
}
debug("remaining in buf: %d, first char: %c", buflen, buf[0]);
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 if (!strcmp(geomname, "8c")) {
geometry = MultirotorMixer::OCTA_COX;
} 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 = constrain(get_control(0, 0) * _roll_scale, -1.0f, 1.0f);
//lowsyslog("roll: %d, get_control0: %d, %d\n", (int)(roll), (int)(get_control(0, 0)), (int)(_roll_scale));
float pitch = constrain(get_control(0, 1) * _pitch_scale, -1.0f, 1.0f);
float yaw = constrain(get_control(0, 2) * _yaw_scale, -1.0f, 1.0f);
float thrust = constrain(get_control(0, 3), 0.0f, 1.0f);
//lowsyslog("thrust: %d, get_control3: %d\n", (int)(thrust), (int)(get_control(0, 3)));
float min_out = 0.0f;
float max_out = 0.0f;
float scale_yaw = 1.0f;
/* perform initial mix pass yielding unbounded outputs, ignore yaw */
for (unsigned i = 0; i < _rotor_count; i++) {
float out = roll * _rotors[i].roll_scale +
pitch * _rotors[i].pitch_scale +
thrust;
/* limit yaw if it causes outputs clipping */
if (out >= 0.0f && out < -yaw * _rotors[i].yaw_scale) {
yaw = -out / _rotors[i].yaw_scale;
}
/* calculate min and max output values */
if (out < min_out) {
min_out = out;
}
if (out > max_out) {
max_out = out;
}
outputs[i] = out;
}
/* scale down roll/pitch controls if some outputs are negative, don't add yaw, keep total thrust */
if (min_out < 0.0) {
float scale_in = thrust / (thrust - min_out);
/* mix again with adjusted controls */
for (unsigned i = 0; i < _rotor_count; i++) {
outputs[i] = scale_in * (roll * _rotors[i].roll_scale + pitch * _rotors[i].pitch_scale) + thrust;
}
} else {
/* roll/pitch mixed without limiting, add yaw control */
for (unsigned i = 0; i < _rotor_count; i++) {
outputs[i] += yaw * _rotors[i].yaw_scale;
}
}
/* scale down all outputs if some outputs are too large, reduce total thrust */
float scale_out;
if (max_out > 1.0f) {
scale_out = 1.0f / max_out;
} else {
scale_out = 1.0f;
}
for (unsigned i = 0; i < _rotor_count; i++) {
outputs[i] = -1.0f + (outputs[i] * 2 * scale_out);
}
/* 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);
}
