/****************************************************************************
*
* Copyright (C) 2008-2013 PX4 Development Team. All rights reserved.
* Author: Samuel Zihlmann <samuezih@ee.ethz.ch>
* Lorenz Meier <lm@inf.ethz.ch>
*
* 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 flow_position_control.c
*
* Optical flow position controller
*/
#include <nuttx/config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <debug.h>
#include <termios.h>
#include <time.h>
#include <math.h>
#include <sys/prctl.h>
#include <drivers/drv_hrt.h>
#include <uORB/uORB.h>
#include <uORB/topics/parameter_update.h>
#include <uORB/topics/vehicle_status.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/manual_control_setpoint.h>
#include <uORB/topics/vehicle_local_position.h>
#include <uORB/topics/vehicle_bodyframe_speed_setpoint.h>
#include <uORB/topics/vehicle_local_position_setpoint.h>
#include <uORB/topics/filtered_bottom_flow.h>
#include <systemlib/systemlib.h>
#include <systemlib/perf_counter.h>
#include <systemlib/err.h>
#include <poll.h>
#include "flow_position_control_params.h"
static bool thread_should_exit = false; /**< Deamon exit flag */
static bool thread_running = false; /**< Deamon status flag */
static int deamon_task; /**< Handle of deamon task / thread */
__EXPORT int flow_position_control_main(int argc, char *argv[]);
/**
* Mainloop of position controller.
*/
static int flow_position_control_thread_main(int argc, char *argv[]);
/**
* Print the correct usage.
*/
static void usage(const char *reason);
static void
usage(const char *reason)
{
if (reason)
fprintf(stderr, "%s\n", reason);
fprintf(stderr, "usage: deamon {start|stop|status} [-p <additional params>]\n\n");
exit(1);
}
/**
* The deamon app only briefly exists to start
* the background job. The stack size assigned in the
* Makefile does only apply to this management task.
*
* The actual stack size should be set in the call
* to task_spawn().
*/
int flow_position_control_main(int argc, char *argv[])
{
if (argc < 1)
usage("missing command");
if (!strcmp(argv[1], "start"))
{
if (thread_running)
{
printf("flow position control already running\n");
/* this is not an error */
exit(0);
}
thread_should_exit = false;
deamon_task = task_spawn("flow_position_control",
SCHED_DEFAULT,
SCHED_PRIORITY_MAX - 6,
4096,
flow_position_control_thread_main,
(argv) ? (const char **)&argv[2] : (const char **)NULL);
exit(0);
}
if (!strcmp(argv[1], "stop"))
{
thread_should_exit = true;
exit(0);
}
if (!strcmp(argv[1], "status"))
{
if (thread_running)
printf("\tflow position control app is running\n");
else
printf("\tflow position control app not started\n");
exit(0);
}
usage("unrecognized command");
exit(1);
}
static int
flow_position_control_thread_main(int argc, char *argv[])
{
/* welcome user */
thread_running = true;
printf("[flow position control] starting\n");
uint32_t counter = 0;
const float time_scale = powf(10.0f,-6.0f);
/* structures */
struct vehicle_status_s vstatus;
struct vehicle_attitude_s att;
struct manual_control_setpoint_s manual;
struct filtered_bottom_flow_s filtered_flow;
struct vehicle_local_position_s local_pos;
struct vehicle_bodyframe_speed_setpoint_s speed_sp;
/* subscribe to attitude, motor setpoints and system state */
int parameter_update_sub = orb_subscribe(ORB_ID(parameter_update));
int vehicle_attitude_sub = orb_subscribe(ORB_ID(vehicle_attitude));
int vehicle_status_sub = orb_subscribe(ORB_ID(vehicle_status));
int manual_control_setpoint_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
int filtered_bottom_flow_sub = orb_subscribe(ORB_ID(filtered_bottom_flow));
int vehicle_local_position_sub = orb_subscribe(ORB_ID(vehicle_local_position));
orb_advert_t speed_sp_pub;
bool speed_setpoint_adverted = false;
/* parameters init*/
struct flow_position_control_params params;
struct flow_position_control_param_handles param_handles;
parameters_init(¶m_handles);
parameters_update(¶m_handles, ¶ms);
/* init flow sum setpoint */
float flow_sp_sumx = 0.0f;
float flow_sp_sumy = 0.0f;
/* init yaw setpoint */
float yaw_sp = 0.0f;
/* init height setpoint */
float height_sp = params.height_min;
/* height controller states */
bool start_phase = true;
bool landing_initialized = false;
float landing_thrust_start = 0.0f;
/* states */
float integrated_h_error = 0.0f;
float last_local_pos_z = 0.0f;
bool update_flow_sp_sumx = false;
bool update_flow_sp_sumy = false;
uint64_t last_time = 0.0f;
float dt = 0.0f; // s
/* register the perf counter */
perf_counter_t mc_loop_perf = perf_alloc(PC_ELAPSED, "flow_position_control_runtime");
perf_counter_t mc_interval_perf = perf_alloc(PC_INTERVAL, "flow_position_control_interval");
perf_counter_t mc_err_perf = perf_alloc(PC_COUNT, "flow_position_control_err");
static bool sensors_ready = false;
while (!thread_should_exit)
{
/* wait for first attitude msg to be sure all data are available */
if (sensors_ready)
{
/* polling */
struct pollfd fds[2] = {
{ .fd = filtered_bottom_flow_sub, .events = POLLIN }, // positions from estimator
{ .fd = parameter_update_sub, .events = POLLIN }
};
/* wait for a position update, check for exit condition every 500 ms */
int ret = poll(fds, 2, 500);
if (ret < 0)
{
/* poll error, count it in perf */
perf_count(mc_err_perf);
}
else if (ret == 0)
{
/* no return value, ignore */
// printf("[flow position control] no filtered flow updates\n");
}
else
{
/* parameter update available? */
if (fds[1].revents & POLLIN)
{
/* read from param to clear updated flag */
struct parameter_update_s update;
orb_copy(ORB_ID(parameter_update), parameter_update_sub, &update);
parameters_update(¶m_handles, ¶ms);
printf("[flow position control] parameters updated.\n");
}
/* only run controller if position/speed changed */
if (fds[0].revents & POLLIN)
{
perf_begin(mc_loop_perf);
/* get a local copy of the vehicle state */
orb_copy(ORB_ID(vehicle_status), vehicle_status_sub, &vstatus);
/* get a local copy of manual setpoint */
orb_copy(ORB_ID(manual_control_setpoint), manual_control_setpoint_sub, &manual);
/* get a local copy of attitude */
orb_copy(ORB_ID(vehicle_attitude), vehicle_attitude_sub, &att);
/* get a local copy of filtered bottom flow */
orb_copy(ORB_ID(filtered_bottom_flow), filtered_bottom_flow_sub, &filtered_flow);
/* get a local copy of local position */
orb_copy(ORB_ID(vehicle_local_position), vehicle_local_position_sub, &local_pos);
// XXX fix this
#if 0
if (vstatus.state_machine == SYSTEM_STATE_AUTO)
{
float manual_pitch = manual.pitch / params.rc_scale_pitch; // 0 to 1
float manual_roll = manual.roll / params.rc_scale_roll; // 0 to 1
float manual_yaw = manual.yaw / params.rc_scale_yaw; // -1 to 1
/* calc dt */
if(last_time == 0)
{
last_time = hrt_absolute_time();
continue;
}
dt = ((float) (hrt_absolute_time() - last_time)) * time_scale;
last_time = hrt_absolute_time();
/* update flow sum setpoint */
if (update_flow_sp_sumx)
{
flow_sp_sumx = filtered_flow.sumx;
update_flow_sp_sumx = false;
}
if (update_flow_sp_sumy)
{
flow_sp_sumy = filtered_flow.sumy;
update_flow_sp_sumy = false;
}
/* calc new bodyframe speed setpoints */
float speed_body_x = (flow_sp_sumx - filtered_flow.sumx) * params.pos_p - filtered_flow.vx * params.pos_d;
float speed_body_y = (flow_sp_sumy - filtered_flow.sumy) * params.pos_p - filtered_flow.vy * params.pos_d;
float speed_limit_height_factor = height_sp; // the settings are for 1 meter
/* overwrite with rc input if there is any */
if(isfinite(manual_pitch) && isfinite(manual_roll))
{
if(fabsf(manual_pitch) > params.manual_threshold)
{
speed_body_x = -manual_pitch * params.limit_speed_x * speed_limit_height_factor;
update_flow_sp_sumx = true;
}
if(fabsf(manual_roll) > params.manual_threshold)
{
speed_body_y = manual_roll * params.limit_speed_y * speed_limit_height_factor;
update_flow_sp_sumy = true;
}
}
/* limit speed setpoints */
if((speed_body_x <= params.limit_speed_x * speed_limit_height_factor) &&
(speed_body_x >= -params.limit_speed_x * speed_limit_height_factor))
{
speed_sp.vx = speed_body_x;
}
else
{
if(speed_body_x > params.limit_speed_x * speed_limit_height_factor)
speed_sp.vx = params.limit_speed_x * speed_limit_height_factor;
if(speed_body_x < -params.limit_speed_x * speed_limit_height_factor)
speed_sp.vx = -params.limit_speed_x * speed_limit_height_factor;
}
if((speed_body_y <= params.limit_speed_y * speed_limit_height_factor) &&
(speed_body_y >= -params.limit_speed_y * speed_limit_height_factor))
{
speed_sp.vy = speed_body_y;
}
else
{
if(speed_body_y > params.limit_speed_y * speed_limit_height_factor)
speed_sp.vy = params.limit_speed_y * speed_limit_height_factor;
if(speed_body_y < -params.limit_speed_y * speed_limit_height_factor)
speed_sp.vy = -params.limit_speed_y * speed_limit_height_factor;
}
/* manual yaw change */
if(isfinite(manual_yaw) && isfinite(manual.throttle))
{
if(fabsf(manual_yaw) > params.manual_threshold && manual.throttle > 0.2f)
{
yaw_sp += manual_yaw * params.limit_yaw_step;
/* modulo for rotation -pi +pi */
if(yaw_sp < -M_PI_F)
yaw_sp = yaw_sp + M_TWOPI_F;
else if(yaw_sp > M_PI_F)
yaw_sp = yaw_sp - M_TWOPI_F;
}
}
/* forward yaw setpoint */
speed_sp.yaw_sp = yaw_sp;
/* manual height control
* 0-20%: thrust linear down
* 20%-40%: down
* 40%-60%: stabilize altitude
* 60-100%: up
*/
float thrust_control = 0.0f;
if (isfinite(manual.throttle))
{
if (start_phase)
{
/* control start thrust with stick input */
if (manual.throttle < 0.4f)
{
/* first 40% for up to feedforward */
thrust_control = manual.throttle / 0.4f * params.thrust_feedforward;
}
else
{
/* second 60% for up to feedforward + 10% */
thrust_control = (manual.throttle - 0.4f) / 0.6f * 0.1f + params.thrust_feedforward;
}
/* exit start phase if setpoint is reached */
if (height_sp < -local_pos.z && thrust_control > params.limit_thrust_lower)
{
start_phase = false;
/* switch to stabilize */
thrust_control = params.thrust_feedforward;
}
}
else
{
if (manual.throttle < 0.2f)
{
/* landing initialization */
if (!landing_initialized)
{
/* consider last thrust control to avoid steps */
landing_thrust_start = speed_sp.thrust_sp;
landing_initialized = true;
}
/* set current height as setpoint to avoid steps */
if (-local_pos.z > params.height_min)
height_sp = -local_pos.z;
else
height_sp = params.height_min;
/* lower 20% stick range controls thrust down */
thrust_control = manual.throttle / 0.2f * landing_thrust_start;
/* assume ground position here */
if (thrust_control < 0.1f)
{
/* reset integral if on ground */
integrated_h_error = 0.0f;
/* switch to start phase */
start_phase = true;
/* reset height setpoint */
height_sp = params.height_min;
}
}
else
{
/* stabilized mode */
landing_initialized = false;
/* calc new thrust with PID */
float height_error = (local_pos.z - (-height_sp));
/* update height setpoint if needed*/
if (manual.throttle < 0.4f)
{
/* down */
if (height_sp > params.height_min + params.height_rate &&
fabsf(height_error) < params.limit_height_error)
height_sp -= params.height_rate * dt;
}
if (manual.throttle > 0.6f)
{
/* up */
if (height_sp < params.height_max &&
fabsf(height_error) < params.limit_height_error)
height_sp += params.height_rate * dt;
}
/* instead of speed limitation, limit height error (downwards) */
if(height_error > params.limit_height_error)
height_error = params.limit_height_error;
else if(height_error < -params.limit_height_error)
height_error = -params.limit_height_error;
integrated_h_error = integrated_h_error + height_error;
float integrated_thrust_addition = integrated_h_error * params.height_i;
if(integrated_thrust_addition > params.limit_thrust_int)
integrated_thrust_addition = params.limit_thrust_int;
if(integrated_thrust_addition < -params.limit_thrust_int)
integrated_thrust_addition = -params.limit_thrust_int;
float height_speed = last_local_pos_z - local_pos.z;
float thrust_diff = height_error * params.height_p - height_speed * params.height_d;
thrust_control = params.thrust_feedforward + thrust_diff + integrated_thrust_addition;
/* add attitude component
* F = Fz / (cos(pitch)*cos(roll)) -> can be found in rotM
*/
// // TODO problem with attitude
// if (att.R_valid && att.R[2][2] > 0)
// thrust_control = thrust_control / att.R[2][2];
/* set thrust lower limit */
if(thrust_control < params.limit_thrust_lower)
thrust_control = params.limit_thrust_lower;
}
}
/* set thrust upper limit */
if(thrust_control > params.limit_thrust_upper)
thrust_control = params.limit_thrust_upper;
}
/* store actual height for speed estimation */
last_local_pos_z = local_pos.z;
speed_sp.thrust_sp = thrust_control;
speed_sp.timestamp = hrt_absolute_time();
/* publish new speed setpoint */
if(isfinite(speed_sp.vx) && isfinite(speed_sp.vy) && isfinite(speed_sp.yaw_sp) && isfinite(speed_sp.thrust_sp))
{
if(speed_setpoint_adverted)
{
orb_publish(ORB_ID(vehicle_bodyframe_speed_setpoint), speed_sp_pub, &speed_sp);
}
else
{
speed_sp_pub = orb_advertise(ORB_ID(vehicle_bodyframe_speed_setpoint), &speed_sp);
speed_setpoint_adverted = true;
}
}
else
{
warnx("NaN in flow position controller!");
}
}
else
{
/* in manual or stabilized state just reset speed and flow sum setpoint */
speed_sp.vx = 0.0f;
speed_sp.vy = 0.0f;
flow_sp_sumx = filtered_flow.sumx;
flow_sp_sumy = filtered_flow.sumy;
if(isfinite(att.yaw))
{
yaw_sp = att.yaw;
speed_sp.yaw_sp = att.yaw;
}
if(isfinite(manual.throttle))
speed_sp.thrust_sp = manual.throttle;
}
#endif
/* measure in what intervals the controller runs */
perf_count(mc_interval_perf);
perf_end(mc_loop_perf);
}
}
counter++;
}
else
{
/* sensors not ready waiting for first attitude msg */
/* polling */
struct pollfd fds[1] = {
{ .fd = vehicle_attitude_sub, .events = POLLIN },
};
/* wait for a flow msg, check for exit condition every 5 s */
int ret = poll(fds, 1, 5000);
if (ret < 0)
{
/* poll error, count it in perf */
perf_count(mc_err_perf);
}
else if (ret == 0)
{
/* no return value, ignore */
printf("[flow position control] no attitude received.\n");
}
else
{
if (fds[0].revents & POLLIN)
{
sensors_ready = true;
printf("[flow position control] initialized.\n");
}
}
}
}
printf("[flow position control] ending now...\n");
thread_running = false;
close(parameter_update_sub);
close(vehicle_attitude_sub);
close(vehicle_local_position_sub);
close(vehicle_status_sub);
close(manual_control_setpoint_sub);
close(speed_sp_pub);
perf_print_counter(mc_loop_perf);
perf_free(mc_loop_perf);
fflush(stdout);
return 0;
}