follower.cpp

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/*
 * Copyright (c) 2011, Willow Garage, Inc.
 * All rights reserved.
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 *     * Neither the name of the Willow Garage, Inc. 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"
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#include "ros/ros.h"
#include "pluginlib/class_list_macros.h"
#include "nodelet/nodelet.h"
#include <geometry_msgs/Twist.h>
#include <pcl_ros/point_cloud.h>
#include <pcl/point_types.h>
#include "dynamic_reconfigure/server.h"
#include "turtlebot_follower/ChangeState.h"
#include "turtlebot_follower/FollowerConfig.h"

#include <visualization_msgs/Marker.h>


namespace turtlebot_follower
{
typedef pcl::PointCloud<pcl::PointXYZ> PointCloud;

//* The turtlebot follower nodelet.
class TurtlebotFollower : public nodelet::Nodelet
{
public:
  TurtlebotFollower() : min_y_(0.1), max_y_(0.5),
                        min_x_(-0.2), max_x_(0.2),
                        max_z_(0.8), goal_z_(0.6),
                        z_scale_(1.0), x_scale_(5.0)
  {

  }

  ~TurtlebotFollower()
  {
    delete config_srv_;
  }

private:
  double min_y_; 
  double max_y_; 
  double min_x_; 
  double max_x_; 
  double max_z_; 
  double goal_z_; 
  double z_scale_; 
  double x_scale_; 
  bool   enabled_; 
  // Service for start/stop following
  ros::ServiceServer switch_srv_;

  // Dynamic reconfigure server
  dynamic_reconfigure::Server<turtlebot_follower::FollowerConfig>* config_srv_;

  virtual void onInit()
  {
    ros::NodeHandle& nh = getNodeHandle();
    ros::NodeHandle& private_nh = getPrivateNodeHandle();

    private_nh.getParam("min_y", min_y_);
    private_nh.getParam("max_y", max_y_);
    private_nh.getParam("min_x", min_x_);
    private_nh.getParam("max_x", max_x_);
    private_nh.getParam("max_z", max_z_);
    private_nh.getParam("goal_z", goal_z_);
    private_nh.getParam("z_scale", z_scale_);
    private_nh.getParam("x_scale", x_scale_);
    private_nh.getParam("enabled", enabled_);

    cmdpub_ = private_nh.advertise<geometry_msgs::Twist> ("cmd_vel", 1);
    markerpub_ = private_nh.advertise<visualization_msgs::Marker>("marker",1);
    bboxpub_ = private_nh.advertise<visualization_msgs::Marker>("bbox",1);
    sub_= nh.subscribe<PointCloud>("depth/points", 1, &TurtlebotFollower::cloudcb, this);

    switch_srv_ = private_nh.advertiseService("change_state", &TurtlebotFollower::changeModeSrvCb, this);

    config_srv_ = new dynamic_reconfigure::Server<turtlebot_follower::FollowerConfig>(private_nh);
    dynamic_reconfigure::Server<turtlebot_follower::FollowerConfig>::CallbackType f =
        boost::bind(&TurtlebotFollower::reconfigure, this, _1, _2);
    config_srv_->setCallback(f);
  }

  void reconfigure(turtlebot_follower::FollowerConfig &config, uint32_t level)
  {
    min_y_ = config.min_y;
    max_y_ = config.max_y;
    min_x_ = config.min_x;
    max_x_ = config.max_x;
    max_z_ = config.max_z;
    goal_z_ = config.goal_z;
    z_scale_ = config.z_scale;
    x_scale_ = config.x_scale;
  }

  void cloudcb(const PointCloud::ConstPtr&  cloud)
  {
    //X,Y,Z of the centroid
    float x = 0.0;
    float y = 0.0;
    float z = 1e6;
    //Number of points observed
    unsigned int n = 0;
    //Iterate through all the points in the region and find the average of the position
    BOOST_FOREACH (const pcl::PointXYZ& pt, cloud->points)
    {
      //First, ensure that the point's position is valid. This must be done in a seperate
      //if because we do not want to perform comparison on a nan value.
      if (!std::isnan(x) && !std::isnan(y) && !std::isnan(z))
      {
        //Test to ensure the point is within the aceptable box.
        if (-pt.y > min_y_ && -pt.y < max_y_ && pt.x < max_x_ && pt.x > min_x_ && pt.z < max_z_)
        {
          //Add the point to the totals
          x += pt.x;
          y += pt.y;
          z = std::min(z, pt.z);
          n++;
        }
      }
    }

    //If there are points, find the centroid and calculate the command goal.
    //If there are no points, simply publish a stop goal.
    if (n>4000)
    {
      x /= n;
      y /= n;
      if(z > max_z_){
        ROS_DEBUG("No valid points detected, stopping the robot");
        if (enabled_)
        {
          cmdpub_.publish(geometry_msgs::TwistPtr(new geometry_msgs::Twist()));
        }
        return;
      }

      ROS_DEBUG("Centroid at %f %f %f with %d points", x, y, z, n);
      publishMarker(x, y, z);

      if (enabled_)
      {
        geometry_msgs::TwistPtr cmd(new geometry_msgs::Twist());
        cmd->linear.x = (z - goal_z_) * z_scale_;
        cmd->angular.z = -x * x_scale_;
        cmdpub_.publish(cmd);
      }
    }
    else
    {
      ROS_DEBUG("No points detected, stopping the robot");
      publishMarker(x, y, z);

      if (enabled_)
      {
        cmdpub_.publish(geometry_msgs::TwistPtr(new geometry_msgs::Twist()));
      }
    }

    publishBbox();
  }

  bool changeModeSrvCb(ChangeState::Request& request, ChangeState::Response& response)
  {
    if ((enabled_ == true) && (request.state == request.STOPPED))
    {
      ROS_INFO("Change mode service request: following stopped");
      cmdpub_.publish(geometry_msgs::TwistPtr(new geometry_msgs::Twist()));
      enabled_ = false;
    }
    else if ((enabled_ == false) && (request.state == request.FOLLOW))
    {
      ROS_INFO("Change mode service request: following (re)started");
      enabled_ = true;
    }

    response.result = response.OK;
    return true;
  }

  void publishMarker(double x,double y,double z)
  {
    visualization_msgs::Marker marker;
    marker.header.frame_id = "/camera_rgb_optical_frame";
    marker.header.stamp = ros::Time();
    marker.ns = "my_namespace";
    marker.id = 0;
    marker.type = visualization_msgs::Marker::SPHERE;
    marker.action = visualization_msgs::Marker::ADD;
    marker.pose.position.x = x;
    marker.pose.position.y = y;
    marker.pose.position.z = z;
    marker.pose.orientation.x = 0.0;
    marker.pose.orientation.y = 0.0;
    marker.pose.orientation.z = 0.0;
    marker.pose.orientation.w = 1.0;
    marker.scale.x = 0.2;
    marker.scale.y = 0.2;
    marker.scale.z = 0.2;
    marker.color.a = 1.0;
    marker.color.r = 1.0;
    marker.color.g = 0.0;
    marker.color.b = 0.0;
    //only if using a MESH_RESOURCE marker type:
    markerpub_.publish( marker );
  }

  void publishBbox()
  {
    double x = (min_x_ + max_x_)/2;
    double y = (min_y_ + max_y_)/2;
    double z = (0 + max_z_)/2;

    double scale_x = (max_x_ - x)*2;
    double scale_y = (max_y_ - y)*2;
    double scale_z = (max_z_ - z)*2;

    visualization_msgs::Marker marker;
    marker.header.frame_id = "/camera_rgb_optical_frame";
    marker.header.stamp = ros::Time();
    marker.ns = "my_namespace";
    marker.id = 1;
    marker.type = visualization_msgs::Marker::CUBE;
    marker.action = visualization_msgs::Marker::ADD;
    marker.pose.position.x = x;
    marker.pose.position.y = -y;
    marker.pose.position.z = z;
    marker.pose.orientation.x = 0.0;
    marker.pose.orientation.y = 0.0;
    marker.pose.orientation.z = 0.0;
    marker.pose.orientation.w = 1.0;
    marker.scale.x = scale_x;
    marker.scale.y = scale_y;
    marker.scale.z = scale_z;
    marker.color.a = 0.5;
    marker.color.r = 0.0;
    marker.color.g = 1.0;
    marker.color.b = 0.0;
    //only if using a MESH_RESOURCE marker type:
    bboxpub_.publish( marker );
  }

  ros::Subscriber sub_;
  ros::Publisher cmdpub_;
  ros::Publisher markerpub_;
  ros::Publisher bboxpub_;
};

PLUGINLIB_DECLARE_CLASS(turtlebot_follower, TurtlebotFollower, turtlebot_follower::TurtlebotFollower, nodelet::Nodelet);

}