Colony » Colony Scout

/**

 * Copyright (c) 2011 Colony Project

 * 

 * Permission is hereby granted, free of charge, to any person

 * obtaining a copy of this software and associated documentation

 * files (the "Software"), to deal in the Software without

 * restriction, including without limitation the rights to use,

 * copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following

 * conditions:

 * 

 * The above copyright notice and this permission notice shall be

 * included in all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

 * OTHER DEALINGS IN THE SOFTWARE.

 **/

/**

 * @file motors.cpp

 * @brief Motors

 *

 * Implementation of functions for motor use.

 *

 * @author Colony Project, CMU Robotics Club

 * @author Benjamin Wasserman

 **/

#include "ros/ros.h"

#include "motors.h"

//#include "libscout/src/constants.h"

#include <cstdlib>

/**

 * @defgroup motors Motors

 * @brief Functions for using the motors

 *

 **/

/* Motor state variables */

/** \todo Fix types: static */

int motor_fl_speed; /**< The current speed of the front left motor. */

int motor_fr_speed; /**< The current speed of the front right motor. */

int motor_bl_speed; /**< The current speed of the back left motor. */

int motor_br_speed; /**< The current speed of the back right motor. */

/*!

 * \brief Motors driver. This is a ROS node that controls motor speeds.

 *

 * This is the main function for the motors node. It is run when the node

 * starts and initializes the motors. It then subscribes to the

 * set_motors, and set_motor_speeds topics, and advertises the

 * query_motors service.

 * 

 * \param argc The number of command line arguments (should be 1)

 * \param argv The array of command line arguments

 **/

int main(int argc, char **argv){

  /* Initialize in ROS the motors driver node */

  ros::init(argc, argv, "motors_driver");

  /* Advertise that this serves the query_motors service */

  ros::NodeHandle n;

  ros::ServiceServer service = n.advertiseService("query_motors", motors_query);

  /* Subscribe to the set_motors topic */

  ros::Subscriber sub0 = n.subscribe("set_motors", 4, motors_set);

  /* Initialize hardware for motors */

  // Hardware init functions here

  ROS_INFO("Ready to set motors.");

  ros::spin();

  return 0;

}

/*!

 * \brief Sets motor speed

 *

 * Sets the motor speeds based on subscription to the set_motors topic.

 *

 * \param msg The message from the set_motors topic, containing speeds and

 *  motor configuration settings.

 */

void motors_set(const motors::set_motors::ConstPtr& msg){

  /** \todo Edit to only set requested motors, not all */ 

  motor_fl_speed = msg->fl_speed;

  motor_fr_speed = msg->fr_speed;

  motor_bl_speed = msg->bl_speed;

  motor_br_speed = msg->br_speed;

}

/*!

 * \brief Outputs current motor speeds

 *

 * Serves the service query_motors by responding to service requests with the

 * speeds of the motors.

 * \param req The request. Should be empty.

 * \param res The response. The fields will be filled with values.

 */

bool motors_query(motors::query_motors::Request &req,

    motors::query_motors::Response &res){

  res.fl_speed = motor_fl_speed;

  res.fr_speed = motor_fr_speed;

  res.bl_speed = motor_bl_speed;

  res.br_speed = motor_br_speed;

  ROS_DEBUG("Motor speeds queried");

  return true;

}