mavlink_control.cpp

/****************************************************************************
 *
 *   Copyright (c) 2014 MAVlink Development Team. All rights reserved.
 *   Author: Trent Lukaczyk, <aerialhedgehog@gmail.com>
 *           Jaycee Lock,    <jaycee.lock@gmail.com>
 *           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
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 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
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 ****************************************************************************/

/**
 * @file mavlink_control.cpp
 *
 * @brief An example offboard control process via mavlink
 *
 * This process connects an external MAVLink UART device to send an receive data
 *
 * @author Trent Lukaczyk, <aerialhedgehog@gmail.com>
 * @author Jaycee Lock,    <jaycee.lock@gmail.com>
 * @author Lorenz Meier,   <lm@inf.ethz.ch>
 *
 */



// ------------------------------------------------------------------------------
//   Includes
// ------------------------------------------------------------------------------

#include "mavlink_control.h"


// ------------------------------------------------------------------------------
//   TOP
// ------------------------------------------------------------------------------
int
top (int argc, char **argv)
{

	// --------------------------------------------------------------------------
	//   PARSE THE COMMANDS
	// --------------------------------------------------------------------------

	// Default input arguments
#ifdef __APPLE__
	char *uart_name = (char*)"/dev/tty.usbmodem1";
#else
	char *uart_name = (char*)"/dev/ttyUSB0";
#endif
	int baudrate = 57600;

	// do the parse, will throw an int if it fails
	parse_commandline(argc, argv, uart_name, baudrate);


	// --------------------------------------------------------------------------
	//   PORT and THREAD STARTUP
	// --------------------------------------------------------------------------

	/*
	 * Instantiate a serial port object
	 *
	 * This object handles the opening and closing of the offboard computer's
	 * serial port over which it will communicate to an autopilot.  It has
	 * methods to read and write a mavlink_message_t object.  To help with read
	 * and write in the context of pthreading, it gaurds port operations with a
	 * pthread mutex lock.
	 *
	 */
	Serial_Port serial_port(uart_name, baudrate);


	/*
	 * Instantiate an autopilot interface object
	 *
	 * This starts two threads for read and write over MAVlink. The read thread
	 * listens for any MAVlink message and pushes it to the current_messages
	 * attribute.  The write thread at the moment only streams a position target
	 * in the local NED frame (mavlink_set_position_target_local_ned_t), which
	 * is changed by using the method update_setpoint().  Sending these messages
	 * are only half the requirement to get response from the autopilot, a signal
	 * to enter "offboard_control" mode is sent by using the enable_offboard_control()
	 * method.  Signal the exit of this mode with disable_offboard_control().  It's
	 * important that one way or another this program signals offboard mode exit,
	 * otherwise the vehicle will go into failsafe.
	 *
	 */
	Autopilot_Interface autopilot_interface(&serial_port);

	/*
	 * Setup interrupt signal handler
	 *
	 * Responds to early exits signaled with Ctrl-C.  The handler will command
	 * to exit offboard mode if required, and close threads and the port.
	 * The handler in this example needs references to the above objects.
	 *
	 */
	serial_port_quit         = &serial_port;
	autopilot_interface_quit = &autopilot_interface;
	signal(SIGINT,quit_handler);

	/*
	 * Start the port and autopilot_interface
	 * This is where the port is opened, and read and write threads are started.
	 */
	serial_port.start();
	autopilot_interface.start();


	// --------------------------------------------------------------------------
	//   RUN COMMANDS
	// --------------------------------------------------------------------------

	/*
	 * Now we can implement the algorithm we want on top of the autopilot interface
	 */
	commands(autopilot_interface);


	// --------------------------------------------------------------------------
	//   THREAD and PORT SHUTDOWN
	// --------------------------------------------------------------------------

	/*
	 * Now that we are done we can stop the threads and close the port
	 */
	autopilot_interface.stop();
	serial_port.stop();


	// --------------------------------------------------------------------------
	//   DONE
	// --------------------------------------------------------------------------

	// woot!
	return 0;

}


// ------------------------------------------------------------------------------
//   COMMANDS
// ------------------------------------------------------------------------------

void
commands(Autopilot_Interface &api)
{

	// --------------------------------------------------------------------------
	//   START OFFBOARD MODE
	// --------------------------------------------------------------------------

	api.enable_offboard_control();
	usleep(100); // give some time to let it sink in

	// now the autopilot is accepting setpoint commands


	// --------------------------------------------------------------------------
	//   SEND OFFBOARD COMMANDS
	// --------------------------------------------------------------------------
	printf("SEND OFFBOARD COMMANDS\n");

	// initialize command data strtuctures
	mavlink_set_position_target_local_ned_t sp;
	mavlink_set_position_target_local_ned_t ip = api.initial_position;

	// autopilot_interface.h provides some helper functions to build the command


	// Example 1 - Set Velocity
//	set_velocity( -1.0       , // [m/s]
//				  -1.0       , // [m/s]
//				   0.0       , // [m/s]
//				   sp        );

	// Example 2 - Set Position
	 set_position( ip.x - 5.0 , // [m]
			 	   ip.y - 5.0 , // [m]
				   ip.z       , // [m]
				   sp         );


	// Example 1.2 - Append Yaw Command
	set_yaw( ip.yaw , // [rad]
			 sp     );

	// SEND THE COMMAND
	api.update_setpoint(sp);
	// NOW pixhawk will try to move

	// Wait for 8 seconds, check position
	for (int i=0; i < 8; i++)
	{
		mavlink_local_position_ned_t pos = api.current_messages.local_position_ned;
		printf("%i CURRENT POSITION XYZ = [ % .4f , % .4f , % .4f ] \n", i, pos.x, pos.y, pos.z);
		sleep(1);
	}

	printf("\n");


	// --------------------------------------------------------------------------
	//   STOP OFFBOARD MODE
	// --------------------------------------------------------------------------

	api.disable_offboard_control();

	// now pixhawk isn't listening to setpoint commands


	// --------------------------------------------------------------------------
	//   GET A MESSAGE
	// --------------------------------------------------------------------------
	printf("READ SOME MESSAGES \n");

	// copy current messages
	Mavlink_Messages messages = api.current_messages;

	// local position in ned frame
	mavlink_local_position_ned_t pos = messages.local_position_ned;
	printf("Got message LOCAL_POSITION_NED (spec: https://pixhawk.ethz.ch/mavlink/#LOCAL_POSITION_NED)\n");
	printf("    pos  (NED):  %f %f %f (m)\n", pos.x, pos.y, pos.z );

	// hires imu
	mavlink_highres_imu_t imu = messages.highres_imu;
	printf("Got message HIGHRES_IMU (spec: https://pixhawk.ethz.ch/mavlink/#HIGHRES_IMU)\n");
	printf("    ap time:     %llu \n", imu.time_usec);
	printf("    acc  (NED):  % f % f % f (m/s^2)\n", imu.xacc , imu.yacc , imu.zacc );
	printf("    gyro (NED):  % f % f % f (rad/s)\n", imu.xgyro, imu.ygyro, imu.zgyro);
	printf("    mag  (NED):  % f % f % f (Ga)\n"   , imu.xmag , imu.ymag , imu.zmag );
	printf("    baro:        %f (mBar) \n"  , imu.abs_pressure);
	printf("    altitude:    %f (m) \n"     , imu.pressure_alt);
	printf("    temperature: %f C \n"       , imu.temperature );

	printf("\n");


	// --------------------------------------------------------------------------
	//   END OF COMMANDS
	// --------------------------------------------------------------------------

	return;

}


// ------------------------------------------------------------------------------
//   Parse Command Line
// ------------------------------------------------------------------------------
// throws EXIT_FAILURE if could not open the port
void
parse_commandline(int argc, char **argv, char *&uart_name, int &baudrate)
{

	// string for command line usage
	const char *commandline_usage = "usage: mavlink_serial -d <devicename> -b <baudrate>";

	// Read input arguments
	for (int i = 1; i < argc; i++) { // argv[0] is "mavlink"

		// Help
		if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
			printf("%s\n",commandline_usage);
			throw EXIT_FAILURE;
		}

		// UART device ID
		if (strcmp(argv[i], "-d") == 0 || strcmp(argv[i], "--device") == 0) {
			if (argc > i + 1) {
				uart_name = argv[i + 1];

			} else {
				printf("%s\n",commandline_usage);
				throw EXIT_FAILURE;
			}
		}

		// Baud rate
		if (strcmp(argv[i], "-b") == 0 || strcmp(argv[i], "--baud") == 0) {
			if (argc > i + 1) {
				baudrate = atoi(argv[i + 1]);

			} else {
				printf("%s\n",commandline_usage);
				throw EXIT_FAILURE;
			}
		}

	}
	// end: for each input argument

	// Done!
	return;
}


// ------------------------------------------------------------------------------
//   Quit Signal Handler
// ------------------------------------------------------------------------------
// this function is called when you press Ctrl-C
void
quit_handler( int sig )
{
	printf("\n");
	printf("TERMINATING AT USER REQUEST\n");
	printf("\n");

	// autopilot interface
	try {
		autopilot_interface_quit->handle_quit(sig);
	}
	catch (int error){}

	// serial port
	try {
		serial_port_quit->handle_quit(sig);
	}
	catch (int error){}

	// end program here
	exit(0);

}


// ------------------------------------------------------------------------------
//   Main
// ------------------------------------------------------------------------------
int
main(int argc, char **argv)
{
	// This program uses throw, wrap one big try/catch here
	try
	{
		int result = top(argc,argv);
		return result;
	}

	catch ( int error )
	{
		fprintf(stderr,"mavlink_control threw exception %i \n" , error);
		return error;
	}

}