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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"
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_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_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 */
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()
{
}
unsigned
MultirotorMixer::mix(float *outputs, unsigned space)
{
float roll = get_control(0, 0) * _roll_scale;
float pitch = get_control(0, 1) * _pitch_scale;
float yaw = get_control(0, 2) * _yaw_scale;
float thrust = 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 0;
}
void
MultirotorMixer::groups_required(uint32_t &groups)
{
/* XXX for now, hardcoded to indexes 0-3 in control group zero */
groups |= (1 << 0);
}
