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 SonarControl.cpp

 * @brief Contains sonar function implementation

 * 

 * @defgroup sonarcontrol SonarControl

 * @brief Functions which a behavior can use to control the sonar.

 * @ingroup behavior

 *

 * @author Colony Project, CMU Robotics Club

 * @author Priyanka Deo

 * @author Alex Zirbel

 *

 * @{

 **/

#include "SonarControl.h"

#define MAX_ATTEMPTS 10

using namespace std;

/**

 * @brief Initialize the sonar module of libscout.

 *

 * Initialize the libscout node as a publisher of sonar_set_scan and 

 * sonar_toggle and a client of query_sonar.

 */

SonarControl::SonarControl(const ros::NodeHandle& libscout_node,

                           string scoutname)

    : node(libscout_node)

{

    sonar_set_scan_client =

        node.serviceClient< ::messages::sonar_set_scan>(scoutname+"/set_sonar_scan");

    sonar_toggle_client = 

        node.serviceClient< ::messages::sonar_toggle>(scoutname + "/toggle_sonar");

    sonar_distance_sub = node.subscribe(scoutname + "/sonar_distance",

                                        QUEUE_SIZE,

                                        &SonarControl::distance_callback,

                                        this);

    // Initialize all the sonar readings to 0 and timestamps to undefined

    for (int i = 0; i < 48; i++)

    {

        readings[i] = 0;

        timestamps[i] = ros::Time::now(); // A common shortcut for no reading

    }

    ROS_INFO("Readings at 0, ready to go.");

    /// @todo Test, and replace 10 with a const int

    num_attempts = MAX_ATTEMPTS;

}

/**

 * Update the array of sonar values, and the last read timestamps,

 * to reflect the new reading received.

 */

void SonarControl::distance_callback(const ::messages::sonar_distance::ConstPtr& msg)

{

    // Error checking so that the array doesn't cause a segfault

    if (msg->pos < 0 || msg-> pos > 23)

    {

        ROS_ERROR("SonarControl received an invalid sonar position.");

        return;

    }

    readings[msg->pos] = msg->distance0;

    readings[msg->pos + 24] = msg->distance1;

    timestamps[msg->pos] = msg->stamp;

    timestamps[msg->pos + 24] = msg->stamp;

}

/**

 * @brief Sets the sonar to a position.

 *

 * @param position Value between 0-180 of degree position to set sonar

 */

void SonarControl::set_single(int position)

{

    set_range(position, position);

}

/**

 * @brief Sets the sonar to scan between two positions

 *

 * @param start_pos The leftmost (smallest) value that the sonar can take

 * @param end_pos The rightmost (largest) value that the sonar can take

 */

void SonarControl::set_range(int start_pos, int end_pos)

{

    // Check that the range is valid

    if (start_pos < 0 || end_pos < 0 || start_pos > 23 || end_pos > 23)

    {

        ROS_ERROR("Commanded SonarControl::set_range to a bad value.");

        return;

    }

    // Sort the start and end positions into increasing order

    if (start_pos > end_pos)

    {

        int temp = start_pos;

        start_pos = end_pos;

        end_pos = temp;

    }

    // Make sure sonar is on

    set_on();

    // Set scan range

    ::messages::sonar_set_scan srv;

    srv.request.stop_l = start_pos;

    srv.request.stop_r = end_pos;

    // Check if the service call failed or if the response was false

    if (!sonar_set_scan_client.call(srv) || srv.response.ack == false)

    {

        if (--num_attempts == 0)

        {

            ROS_ERROR("SonarControl::set_range() failed permanently.");

        }

        ROS_WARN("SonarControl::set_range() failed once.");

    }

}

/**

 * @brief Turn on sonar readings

 *

 * (Re)starts sonar panning and taking readings.

 */

void SonarControl::set_on()

{

    set_power(true);

}

/**

 * @brief Turn off sonar readings

 *

 * Stops sonar from panning and taking readings.

 */

void SonarControl::set_off()

{

    set_power(false);

}

/**

 * @brief Turn sonar readings either off or on.

 *

 * Attempts to turn the readings off or on, num_attempts times.

 *

 * @param is_on True if power should be set on, false if should be off.

 */

void SonarControl::set_power(bool is_on)

{

    ::messages::sonar_toggle srv;

    srv.request.set_on = is_on;

    // Check if the service call failed or if the response was false

    if (!sonar_toggle_client.call(srv) || srv.response.ack == false)

    {

        if (--num_attempts == 0)

        {

            ROS_ERROR("SonarControl::set_power() failed permanently.");

        }

        ROS_WARN("SonarControl::set_power() failed once.");

    }

    ROS_INFO("SonarControl::set_power() succeeded.");

    // Reset num_attempts

    num_attempts = MAX_ATTEMPTS;

}

int* SonarControl::get_sonar_readings()

{

  return readings;

}

/**

 * @brief Converts value returne by sonar to physical distances.

 *

 * @param sonar_value The returned value of the sonar

 * @return The physical distance measured by the sonar.

 **/

//float sonar_to_dist(float sonar_value)

//{

    //@todo impelement later based on sonar readings

//    return sonar_value;

//}

/**

 * @brief Converts values from physical distances to values read by sonar

 *

 * @param distance The physical distance as measured.

 * @return The value read by the sonar that corresponds to the given distance

 **/

//float dist_to_sonar(float distance)

//{

    //@todo implement later based on sonar readings

//    return distance;

//}

/** @} */