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 Contains code to control the motors.

 *

 * Implementation of functions for motor use.

 *

 * @author Colony Project, CMU Robotics Club

 * @author Ben Wasserman

 */

#include <ros/ros.h>

#include <cstdlib>

#include <fstream>

#include "motors.h"

using namespace std;

/**

 * @defgroup motors Motors

 * @brief Functions for using the motors

 *

 * @{

 */

/* Motor state variables

 * Speeds expressed as absolute speed out of max speed (0 - +-MAXSPEED)

 * Absolute speed is the speed written to the hardware to move the motors

 */

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

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

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

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

static fstream motor_fl_file; /**< The device file for the front left motor. */

static fstream motor_fr_file; /**< The device file for the front right motor. */

static fstream motor_bl_file; /**< The device file for the back left motor. */

static fstream motor_br_file; /**< The device file for the back right motor. */

/**

 * @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)

{

    if(msg->fl_set)

    {

      motor_fl_speed = msg->fl_speed;

      motor_fl_file << motor_fl_speed;

    }

    if(msg->fr_set)

    {

      motor_fr_speed = msg->fr_speed;

      motor_fr_file << motor_fr_speed;

    }

    if(msg->bl_set)

    {

      motor_bl_speed = msg->bl_speed;

      motor_bl_file << motor_bl_speed;

    }

    if(msg->br_set)

    {

      motor_br_speed = msg->br_speed;

      motor_br_file << motor_br_speed;

    }

    ROS_DEBUG("Motor speeds set");

}

/**

 * @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. The only field is the units requested.

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

 */

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

                  motors::query_motors::Response &res)

{

    /** @todo Are we checking hardware or just using the saved values?

     *  Saved values sound fine to me (Alex). Pleas confirm.

     *  I think saved values are ok; they're read in from hardware at the

     *  beginning (Tom). */

    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;

}

/**

 * @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 node;

    ros::ServiceServer service = node.advertiseService("query_motors",

                                                       motors_query);

    /* Subscribe to the set_motors topic */

    ros::Subscriber sub0 = node.subscribe("set_motors", QUEUE_SIZE, motors_set);

    /* Open device files for PWM values */

    /** @todo These are probably not the correct order */

    motor_fl_file.open("/dev/pwm8");

    motor_fr_file.open("/dev/pwm9");

    motor_bl_file.open("/dev/pwm10");

    motor_br_file.open("/dev/pwm11");

    /* Get initial values, for motor queries */

    motor_fl_file >> motor_fl_speed;

    motor_fr_file >> motor_fr_speed;

    motor_bl_file >> motor_bl_speed;

    motor_br_file >> motor_br_speed;

    ROS_INFO("Motors node ready.");

    ros::spin();

    return 0;

}

/** @} */