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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 <px4iofirmware/protocol.h>
#include "mixer.h"
// This file is generated by the multi_tables script which is invoked during the build process
#include "mixer_multirotor.generated.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);
}
} // anonymous namespace
MultirotorMixer::MultirotorMixer(ControlCallback control_cb,
uintptr_t cb_handle,
MultirotorGeometry geometry,
float roll_scale,
float pitch_scale,
float yaw_scale,
float idle_speed) :
Mixer(control_cb, cb_handle),
_roll_scale(roll_scale),
_pitch_scale(pitch_scale),
_yaw_scale(yaw_scale),
_idle_speed(-1.0f + idle_speed * 2.0f), /* shift to output range here to avoid runtime calculation */
_limits_pub(),
_rotor_count(_config_rotor_count[(MultirotorGeometryUnderlyingType)geometry]),
_rotors(_config_index[(MultirotorGeometryUnderlyingType)geometry])
{
}
MultirotorMixer::~MultirotorMixer()
{
}
MultirotorMixer *
MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handle, const char *buf, unsigned &buflen)
{
MultirotorGeometry geometry;
char geomname[8];
int s[4];
int used;
/* 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 = MultirotorGeometry::QUAD_PLUS;
} else if (!strcmp(geomname, "4x")) {
geometry = MultirotorGeometry::QUAD_X;
} else if (!strcmp(geomname, "4v")) {
geometry = MultirotorGeometry::QUAD_V;
} else if (!strcmp(geomname, "4w")) {
geometry = MultirotorGeometry::QUAD_WIDE;
} else if (!strcmp(geomname, "4dc")) {
geometry = MultirotorGeometry::QUAD_DEADCAT;
} else if (!strcmp(geomname, "6+")) {
geometry = MultirotorGeometry::HEX_PLUS;
} else if (!strcmp(geomname, "6x")) {
geometry = MultirotorGeometry::HEX_X;
} else if (!strcmp(geomname, "6c")) {
geometry = MultirotorGeometry::HEX_COX;
} else if (!strcmp(geomname, "8+")) {
geometry = MultirotorGeometry::OCTA_PLUS;
} else if (!strcmp(geomname, "8x")) {
geometry = MultirotorGeometry::OCTA_X;
} else if (!strcmp(geomname, "8c")) {
geometry = MultirotorGeometry::OCTA_COX;
} else if (!strcmp(geomname, "2-")) {
geometry = MultirotorGeometry::TWIN_ENGINE;
} else if (!strcmp(geomname, "3y")) {
geometry = MultirotorGeometry::TRI_Y;
} 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, uint16_t *status_reg)
{
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;
if (status_reg != NULL) {
(*status_reg) = 0;
}
/* 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;
out *= _rotors[i].out_scale;
/* limit yaw if it causes outputs clipping */
if (out >= 0.0f && out < -yaw * _rotors[i].yaw_scale) {
yaw = -out / _rotors[i].yaw_scale;
if(status_reg != NULL) {
(*status_reg) |= PX4IO_P_STATUS_MIXER_YAW_LIMIT;
}
}
/* 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 < 0.0f) {
float scale_in = thrust / (thrust - min_out);
max_out = 0.0f;
/* mix again with adjusted controls */
for (unsigned i = 0; i < _rotor_count; i++) {
float out = scale_in * (roll * _rotors[i].roll_scale + pitch * _rotors[i].pitch_scale) + thrust;
/* update max output value */
if (out > max_out) {
max_out = out;
}
outputs[i] = out;
}
if(status_reg != NULL) {
(*status_reg) |= PX4IO_P_STATUS_MIXER_LOWER_LIMIT;
}
} else {
/* roll/pitch mixed without lower side 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;
if(status_reg != NULL) {
(*status_reg) |= PX4IO_P_STATUS_MIXER_UPPER_LIMIT;
}
} else {
scale_out = 1.0f;
}
/* scale outputs to range _idle_speed..1, and do final limiting */
for (unsigned i = 0; i < _rotor_count; i++) {
outputs[i] = constrain(_idle_speed + (outputs[i] * (1.0f - _idle_speed) * scale_out), _idle_speed, 1.0f);
}
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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