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base_control.cpp

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/*
 * simple_base_control.cpp
 *
 *  Created on: Sep 10, 2010
 *      Author: Sebastian Haug | Bosch RTC
 *
 *  Controls PR2 Base. Provides easy to use high level interface
 *  to move and rotate base. No further services have to be launched.
 *
 *  How to use:
 *     - Configured as Library. Add dependency to in simple_base_control_cpp
 *       in own ROS package and instantiate SimpleBaseControl object.
 */

#include "simple_robot_control/base_control.h"

namespace simple_robot_control{

Base::Base()
{
        init();
}

Base::~Base()
{ }

void Base::init()
{
        // init cmd_
        cmd_.linear.x = cmd_.linear.y = cmd_.angular.z = 0;

        // register publisher
        pub_base_vel_ = nh_.advertise<geometry_msgs::Twist>("/base_controller/command", 1);
}

// Drive forward a specified distance in m with given speed in m/s
bool Base::driveForward(double distance, double speed)
{
        geometry_msgs::Twist vel;
        vel.linear.x = std::abs(speed);

        return drive(distance, vel);
}

// Drive right a specified distance in m with given speed in m/s
bool Base::driveRight(double distance, double speed)
{
        geometry_msgs::Twist vel;
        vel.linear.y = -std::abs(speed);

        return drive(distance, vel);
}

// Drive back a specified distance in m with given speed in m/s
bool Base::driveBack(double distance, double speed)
{
        geometry_msgs::Twist vel;
        vel.linear.x = -std::abs(speed);

        return drive(distance, vel);
}

// Drive left a specified distance in m with given speed in m/s
bool Base::driveLeft(double distance, double speed)
{
        geometry_msgs::Twist vel;
        vel.linear.y = std::abs(speed);

        return drive(distance, vel);
}

// Drive a specified distance (based on base odometry information) with given velocity Twist (vector)
bool Base::drive(double distance, const geometry_msgs::Twist& velocity)
{
        tf::StampedTransform start_transform;
        tf::StampedTransform current_transform;

        // Wait and get transform
        tf_listener_odom_.waitForTransform("base_footprint", "odom_combined", ros::Time(0), ros::Duration(5.0));
        tf_listener_odom_.lookupTransform("base_footprint", "odom_combined", ros::Time(0), start_transform);

        // Set cmd_ to velocity and clear angular and linear.z;
        cmd_ = velocity;
        cmd_.angular.x = cmd_.angular.y = cmd_.angular.z = cmd_.linear.z = 0;



        // Loop until pos reached
        ros::Rate rate(PUBLISH_RATE_);
        bool done = false;

        while (!done && nh_.ok()) {
                // Send the drive command
                pub_base_vel_.publish(cmd_);
                rate.sleep();

                // Get the current transform
                try {
                        tf_listener_odom_.lookupTransform("base_footprint", "odom_combined", ros::Time(0), current_transform);
                } catch (tf::TransformException ex) {
                        ROS_ERROR("%s",ex.what());
                        break;
                }

                // See how far we've traveled
                tf::Transform relative_transform = start_transform.inverse() * current_transform;
                double dist_moved = relative_transform.getOrigin().length();


                if (dist_moved >= distance)
                        done = true;
        }
        return done;
}

// Rotate as specified in rad (based on base odometry information) with given speed in rad/s
bool Base::turn(bool clockwise, double radians, double speed)
{
        while (radians < 0)                     radians += 2 * M_PI;
        while (radians > 2 * M_PI)      radians -= 2 * M_PI;

        tf::StampedTransform start_transform;
        tf::StampedTransform current_transform;

        // Wait and get transform
        tf_listener_odom_.waitForTransform("base_footprint", "odom_combined", ros::Time(0), ros::Duration(5.0));
        tf_listener_odom_.lookupTransform("base_footprint", "odom_combined", ros::Time(0), start_transform);

        // Set cmd_
        cmd_.linear.x = cmd_.linear.y = cmd_.linear.z = 0.0;
        cmd_.angular.z = speed;
        if (clockwise)
                cmd_.angular.z = -speed ;



        // The axis we want to be rotating by
        tf::Vector3 desired_turn_axis(0, 0, 1);
        if (!clockwise)
                desired_turn_axis = -desired_turn_axis;

        // Loop until finished turn
        ros::Rate rate(PUBLISH_RATE_);
        bool done = false;

        while (!done && nh_.ok()) {
                // Send the drive command
                pub_base_vel_.publish(cmd_);
                rate.sleep();

                // Get the current transform
                try {
                        tf_listener_odom_.lookupTransform("base_footprint", "odom_combined", ros::Time(0), current_transform);
                } catch (tf::TransformException ex) {
                        ROS_ERROR("%s",ex.what());
                        break;
                }
                tf::Transform relative_transform = start_transform.inverse() * current_transform;
                tf::Vector3 actual_turn_axis = relative_transform.getRotation().getAxis();
                double angle_turned = relative_transform.getRotation().getAngle();
                if (fabs(angle_turned) < 1.0e-2)
                        continue;

                if (actual_turn_axis.dot(desired_turn_axis) < 0)
                        angle_turned = 2 * M_PI - angle_turned;

                if (angle_turned > radians)
                        done = true;
        }
        return done;
}

}

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simple_robot_control
Author(s): Christian Bersch, Sebastian Haug (Maintained by Benjamin Pitzer)
autogenerated on Mon Mar 4 11:12:09 2013