aboutsummaryrefslogtreecommitdiff
path: root/apps/ardrone_control/position_control.c
blob: 6ba165459503aef2948e4a90d72167d09084ea70 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
/****************************************************************************
 * ardrone_control/position_control.c
 *
 *   Copyright (C) 2008, 2012 Thomas Gubler, Julian Oes, Lorenz Meier. All rights reserved.
 *   Author: Based on the pixhawk quadrotor controller
 *
 * 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 NuttX 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.
 *
 ****************************************************************************/

#include "position_control.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include <stdbool.h>
#include <float.h>
#include "pid.h"

#ifndef FM_PI
#define FM_PI 3.1415926535897932384626433832795f
#endif



#define CONTROL_PID_POSITION_INTERVAL	0.020

int read_lock_position(global_data_position_t *position)
{
	static int ret;
	ret = global_data_wait(&global_data_position->access_conf);

	if (ret == 0) {
		memcpy(&position->lat, &global_data_position->lat, sizeof(global_data_position->lat));
		memcpy(&position->lon, &global_data_position->lon, sizeof(global_data_position->lon));
		memcpy(&position->alt, &global_data_position->alt, sizeof(global_data_position->alt));
		memcpy(&position->relative_alt, &global_data_position->relative_alt, sizeof(global_data_position->relative_alt));
		memcpy(&position->vx, &global_data_position->vx, sizeof(global_data_position->vx));
		memcpy(&position->vy, &global_data_position->vy, sizeof(global_data_position->vy));
		memcpy(&position->vz, &global_data_position->vz, sizeof(global_data_position->vz));
		memcpy(&position->hdg, &global_data_position->hdg, sizeof(global_data_position->hdg));


	} else {
		printf("Controller timeout, no new position values available\n");
	}

	global_data_unlock(&global_data_position->access_conf);
	return ret;
}

float get_distance_to_next_waypoint(float lat_now, float lon_now, float lat_next, float lon_next)
{
	double lat_now_rad = lat_now / 180.0 * M_PI;
	double lon_now_rad = lon_now / 180.0 * M_PI;
	double lat_next_rad = lat_next / 180.0 * M_PI;
	double lon_next_rad = lon_next / 180.0 * M_PI;


	double d_lat = lat_next_rad - lat_now_rad;
	double d_lon = lon_next_rad - lon_now_rad;

	double a = sin(d_lat / 2.0) * sin(d_lat / 2.0) + sin(d_lon / 2.0) * sin(d_lon / 2.0) * cos(lat_now_rad) * cos(lat_next_rad);
	double c = 2 * atan2(sqrt(a), sqrt(1 - a));

	const double radius_earth = 6371000.0;

	return radius_earth * c;
}

float get_bearing_to_next_waypoint(float lat_now, float lon_now, float lat_next, float lon_next)
{
	double lat_now_rad = lat_now / 180.0 * M_PI;
	double lon_now_rad = lon_now / 180.0 * M_PI;
	double lat_next_rad = lat_next / 180.0 * M_PI;
	double lon_next_rad = lon_next / 180.0 * M_PI;

	double d_lat = lat_next_rad - lat_now_rad;
	double d_lon = lon_next_rad - lon_now_rad;


	float theta = atan2f(sin(d_lon) * cos(lat_next_rad) , cos(lat_now_rad) * sin(lat_next_rad) - sin(lat_now_rad) * cos(lat_next_rad) * cos(d_lon));

	if (theta < 0) {
		theta = theta + 2 * FM_PI;
	}

	return theta;
}

void control_position(void)
{
	static PID_t distance_controller;

	static int read_ret;
	static global_data_position_t position_estimated;

	static uint16_t counter;

	static bool initialized;
	static uint16_t pm_counter;

	static float lat_next;
	static float lon_next;

	static float pitch_current;

	static float thrust_total;


	if (initialized == false) {

		global_data_lock(&global_data_parameter_storage->access_conf);

		pid_init(&distance_controller,
			 global_data_parameter_storage->pm.param_values[PARAM_PID_POS_P],
			 global_data_parameter_storage->pm.param_values[PARAM_PID_POS_I],
			 global_data_parameter_storage->pm.param_values[PARAM_PID_POS_D],
			 global_data_parameter_storage->pm.param_values[PARAM_PID_POS_AWU],
			 PID_MODE_DERIVATIV_CALC, 150);//150

//		pid_pos_lim = global_data_parameter_storage->pm.param_values[PARAM_PID_POS_LIM];
//		pid_pos_z_lim = global_data_parameter_storage->pm.param_values[PARAM_PID_POS_Z_LIM];

		pm_counter = global_data_parameter_storage->counter;

		global_data_unlock(&global_data_parameter_storage->access_conf);

		thrust_total = 0.0f;

		/* Position initialization */
		/* Wait for new position estimate */
		do {
			read_ret = read_lock_position(&position_estimated);
		} while (read_ret != 0);

		lat_next = position_estimated.lat;
		lon_next = position_estimated.lon;

		/* attitude initialization */
		global_data_lock(&global_data_attitude->access_conf);
		pitch_current = global_data_attitude->pitch;
		global_data_unlock(&global_data_attitude->access_conf);

		initialized = true;
	}

	/* load new parameters with 10Hz */
	if (counter % 50 == 0) {
		if (global_data_trylock(&global_data_parameter_storage->access_conf) == 0) {
			/* check whether new parameters are available */
			if (global_data_parameter_storage->counter > pm_counter) {
				pid_set_parameters(&distance_controller,
						   global_data_parameter_storage->pm.param_values[PARAM_PID_POS_P],
						   global_data_parameter_storage->pm.param_values[PARAM_PID_POS_I],
						   global_data_parameter_storage->pm.param_values[PARAM_PID_POS_D],
						   global_data_parameter_storage->pm.param_values[PARAM_PID_POS_AWU]);

//
//				pid_pos_lim = global_data_parameter_storage->pm.param_values[PARAM_PID_POS_LIM];
//				pid_pos_z_lim = global_data_parameter_storage->pm.param_values[PARAM_PID_POS_Z_LIM];

				pm_counter = global_data_parameter_storage->counter;
				printf("Position controller changed pid parameters\n");
			}
		}

		global_data_unlock(&global_data_parameter_storage->access_conf);
	}


	/* Wait for new position estimate */
	do {
		read_ret = read_lock_position(&position_estimated);
	} while (read_ret != 0);

	/* Get next waypoint */ //TODO: add local copy

	if (0 == global_data_trylock(&global_data_position_setpoint->access_conf)) {
		lat_next = global_data_position_setpoint->x;
		lon_next = global_data_position_setpoint->y;
		global_data_unlock(&global_data_position_setpoint->access_conf);
	}

	/* Get distance to waypoint */
	float distance_to_waypoint = get_distance_to_next_waypoint(position_estimated.lat , position_estimated.lon, lat_next, lon_next);
//	if(counter % 5 == 0)
//		printf("distance_to_waypoint: %.4f\n", distance_to_waypoint);

	/* Get bearing to waypoint (direction on earth surface to next waypoint) */
	float bearing = get_bearing_to_next_waypoint(position_estimated.lat, position_estimated.lon, lat_next, lon_next);

	if (counter % 5 == 0)
		printf("bearing: %.4f\n", bearing);

	/* Calculate speed in direction of bearing (needed for controller) */
	float speed_norm = sqrtf(position_estimated.vx  * position_estimated.vx + position_estimated.vy * position_estimated.vy);
//	if(counter % 5 == 0)
//		printf("speed_norm: %.4f\n", speed_norm);
	float speed_to_waypoint = 0; //(position_estimated.vx * cosf(bearing) + position_estimated.vy * sinf(bearing))/speed_norm; //FIXME, TODO: re-enable this once we have a full estimate of the speed, then we can do a PID for the distance controller

	/* Control Thrust in bearing direction  */
	float horizontal_thrust = -pid_calculate(&distance_controller, 0, distance_to_waypoint, speed_to_waypoint,
				  CONTROL_PID_POSITION_INTERVAL); //TODO: maybe this "-" sign is an error somewhere else

//	if(counter % 5 == 0)
//		printf("horizontal thrust: %.4f\n", horizontal_thrust);

	/* Get total thrust (from remote for now) */
	if (0 == global_data_trylock(&global_data_rc_channels->access_conf)) {
		thrust_total = (float)global_data_rc_channels->chan[THROTTLE].scale; 												//TODO: how should we use the RC_CHANNELS_FUNCTION enum?
		global_data_unlock(&global_data_rc_channels->access_conf);
	}

	const float max_gas = 500.0f;
	thrust_total *= max_gas / 20000.0f; //TODO: check this
	thrust_total += max_gas / 2.0f;


	if (horizontal_thrust > thrust_total) {
		horizontal_thrust = thrust_total;

	} else if (horizontal_thrust < -thrust_total) {
		horizontal_thrust = -thrust_total;
	}



	//TODO: maybe we want to add a speed controller later...

	/* Calclulate thrust in east and north direction */
	float thrust_north = cosf(bearing) * horizontal_thrust;
	float thrust_east = sinf(bearing) * horizontal_thrust;

	if (counter % 10 == 0) {
		printf("thrust north: %.4f\n", thrust_north);
		printf("thrust east: %.4f\n", thrust_east);
		fflush(stdout);
	}

	/* Get current attitude */
	if (0 == global_data_trylock(&global_data_attitude->access_conf)) {
		pitch_current = global_data_attitude->pitch;
		global_data_unlock(&global_data_attitude->access_conf);
	}

	/* Get desired pitch & roll */
	float pitch_desired = 0.0f;
	float roll_desired = 0.0f;

	if (thrust_total != 0) {
		float pitch_fraction = -thrust_north / thrust_total;
		float roll_fraction = thrust_east / (cosf(pitch_current) * thrust_total);

		if (roll_fraction < -1) {
			roll_fraction = -1;

		} else if (roll_fraction > 1) {
			roll_fraction = 1;
		}

//		if(counter % 5 == 0)
//		{
//			printf("pitch_fraction: %.4f, roll_fraction: %.4f\n",pitch_fraction, roll_fraction);
//			fflush(stdout);
//		}

		pitch_desired = asinf(pitch_fraction);
		roll_desired = asinf(roll_fraction);
	}

	/*Broadcast desired angles */
	global_data_lock(&global_data_ardrone_control->access_conf);
	global_data_ardrone_control->attitude_setpoint_navigationframe_from_positioncontroller[0] = roll_desired;
	global_data_ardrone_control->attitude_setpoint_navigationframe_from_positioncontroller[1] = pitch_desired;
	global_data_ardrone_control->attitude_setpoint_navigationframe_from_positioncontroller[2] = bearing; //TODO: add yaw setpoint
	global_data_unlock(&global_data_ardrone_control->access_conf);
	global_data_broadcast(&global_data_ardrone_control->access_conf);


	counter++;
}