object_controller_plugin.cc

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/*
    Copyright (c) 2010, Daniel Hewlett, Antons Rebguns
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:
        * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
        * Neither the name of the <organization> 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 Antons Rebguns <email> ''AS IS'' AND ANY
    EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL Antons Rebguns <email> BE LIABLE FOR ANY
    DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#include <segbot_gazebo_plugins/object_controller_plugin.h>

#include <math/gzmath.hh>
#include <sdf/sdf.hh>

#include <ros/ros.h>
#include <tf/transform_broadcaster.h>
#include <tf/transform_listener.h>
#include <geometry_msgs/Twist.h>
#include <nav_msgs/GetMap.h>
#include <nav_msgs/Odometry.h>
#include <boost/bind.hpp>
#include <boost/thread/mutex.hpp>

namespace gazebo {

  ObjectControllerPlugin::ObjectControllerPlugin() {}

  ObjectControllerPlugin::~ObjectControllerPlugin() {
    delete rosnode_;
    delete transform_broadcaster_;
  }

  // Load the controller
  void ObjectControllerPlugin::Load(physics::ModelPtr _parent, 
      sdf::ElementPtr _sdf) {

    this->parent = _parent;
    this->world = _parent->GetWorld();

    /* Parse parameters - all params are optional */

    this->modelNamespace = "";
    if (!_sdf->HasElement("robotNamespace")) {
      ROS_INFO("OCPlugin missing <robotNamespace>, defaults to \"%s\"", 
          this->modelNamespace.c_str());
    } else {
      this->modelNamespace = 
        _sdf->GetElement("robotNamespace")->GetValueString();
    }

    this->topicName = "cmd_vel";
    if (!_sdf->HasElement("topicName")) {
      ROS_WARN("OCPlugin (%s) missing <topicName>, defaults to \"%s\"", 
          this->modelNamespace.c_str(), this->topicName.c_str());
    } else {
      this->topicName = _sdf->GetElement("topicName")->GetValueString();
    }

    this->globalFrame = "/map";
    if (!_sdf->HasElement("globalFrame")) {
      ROS_WARN("OCPlugin (%s) missing globalFrame, defaults to \"%s\"",
          this->modelNamespace.c_str(), this->globalFrame.c_str());
    } else {
      this->globalFrame = _sdf->GetElement("globalFrame")->GetValueString();
    }

    this->updateRate = 100.0;
    if (!_sdf->HasElement("updateRate")) {
      ROS_WARN("OCPlugin (%s) missing <updateRate>, defaults to %f",
          this->modelNamespace.c_str(), this->updateRate);
    } else {
      this->updateRate = _sdf->GetElement("updateRate")->GetValueDouble();
    }

    this->mapTopic = "map";
    if (!_sdf->HasElement("mapTopic")) {
      ROS_WARN("OCPlugin (%s) missing <mapTopic>, defaults to \"%s\"",
          this->modelNamespace.c_str(), this->mapTopic.c_str());
    } else {
      this->mapTopic = _sdf->GetElement("mapTopic")->GetValueString();
    }

    this->modelRadius = 0.5;
    if (!_sdf->HasElement("modelRadius")) {
      ROS_WARN("OCPlugin (%s) missing <modelRadius>, defaults to %f",
          this->modelNamespace.c_str(), this->modelRadius);
    } else {
      this->modelRadius = _sdf->GetElement("modelRadius")->GetValueDouble();
    }

    this->modelPadding = 0.05;
    if (!_sdf->HasElement("modelPadding")) {
      ROS_WARN("OCPlugin (%s) missing <modelPadding>, defaults to %f",
          this->modelNamespace.c_str(), this->modelPadding);
    } else {
      this->modelPadding = _sdf->GetElement("modelPadding")->GetValueDouble();
    }
    this->circumscribed_model_distance_ = 
      this->modelPadding + this->modelRadius;

    timeout_period_ = 0.0;

    // Initialize update rate stuff
    if (this->updateRate > 0.0) {
      this->update_period_ = 1.0 / this->updateRate;
    } else {
      this->update_period_ = 0.0;
    }
    last_update_time_ = this->world->GetSimTime();

    // Initialize velocity stuff
    last_odom_pose_ = this->parent->GetWorldPose();

    x_ = 0;
    y_ = 0;
    rot_ = 0;
    alive_ = true;

    // Initialize the ROS node and subscribe to cmd_vel
    int argc = 0;
    char** argv = NULL;
    ros::init(argc, argv, "object_controller_plugin", 
        ros::init_options::NoSigintHandler | ros::init_options::AnonymousName);
    rosnode_ = new ros::NodeHandle(this->modelNamespace);

    ROS_DEBUG("OCPlugin (%s) has started!", 
        this->modelNamespace.c_str());

    tf_prefix_ = tf::getPrefixParam(*rosnode_);
    transform_broadcaster_ = new tf::TransformBroadcaster();

    // ROS: Subscribe to the velocity command topic (usually "cmd_vel")
    ros::SubscribeOptions so =
      ros::SubscribeOptions::create<geometry_msgs::Twist>(topicName, 1,
          boost::bind(&ObjectControllerPlugin::cmdVelCallback, this, _1),
          ros::VoidPtr(), &queue_);

    sub_ = rosnode_->subscribe(so);

    ROS_DEBUG("OCPlugin (%s) is subscribing to the map: %s", 
        this->modelNamespace.c_str(), 
        (rosnode_->resolveName(mapTopic)).c_str());
    ros::SubscribeOptions so2 =
      ros::SubscribeOptions::create<nav_msgs::OccupancyGrid>(mapTopic, 1,
          boost::bind(&ObjectControllerPlugin::getSimpleMap, this, _1),
          ros::VoidPtr(), &queue_);
    sub2_ = rosnode_->subscribe(so2);
    map_available_ = false;

    pub_ = rosnode_->advertise<nav_msgs::Odometry>("odom", 1);
    pub2_ = 
      rosnode_->advertise<nav_msgs::OccupancyGrid>("expanded_map", 1, true);

    ros::AdvertiseServiceOptions so3 = 
      ros::AdvertiseServiceOptions::create<segbot_gazebo_plugins::UpdatePluginState>(
          "update_state", 
          boost::bind(&ObjectControllerPlugin::updateState, this, _1, _2), 
          ros::VoidPtr(), &queue_
          );

    update_state_service_server_ = rosnode_->advertiseService(so3);
    pause_ = false;

    // start custom queue for diff drive
    this->callback_queue_thread_ = 
      boost::thread(boost::bind(&ObjectControllerPlugin::QueueThread, this));

    // listen to the update event (broadcast every simulation iteration)
    this->updateConnection = 
      event::Events::ConnectWorldUpdateStart(
          boost::bind(&ObjectControllerPlugin::UpdateChild, this));

  }

  // Update the controller
  void ObjectControllerPlugin::UpdateChild() {
    common::Time current_time = this->world->GetSimTime();
    double seconds_since_last_update = 
      (current_time - last_update_time_).Double();
    if (seconds_since_last_update > update_period_) {
      if (timeout_period_ != 0.0) {
        if ((current_time - time_of_last_message_).Double() > timeout_period_) {
          boost::mutex::scoped_lock scoped_lock(lock);
          x_ = y_ = rot_ = 0;
        }
      }
      boost::mutex::scoped_lock scoped_lock(state_lock_);
      if (!pause_) {
        writePositionData(seconds_since_last_update);
      }
      publishOdometry(seconds_since_last_update);
      last_update_time_+= common::Time(update_period_);
    }
  }

  // Finalize the controller
  void ObjectControllerPlugin::FiniChild() {
    alive_ = false;
    queue_.clear();
    queue_.disable();
    rosnode_->shutdown();
    callback_queue_thread_.join();
  }

  bool ObjectControllerPlugin::updateState(
      segbot_gazebo_plugins::UpdatePluginState::Request &req,
      segbot_gazebo_plugins::UpdatePluginState::Response &resp) {

    boost::mutex::scoped_lock scoped_lock(state_lock_);
    pause_ = req.pause;

    return true;
  }

  void ObjectControllerPlugin::cmdVelCallback(
      const geometry_msgs::Twist::ConstPtr& cmd_msg) {
    boost::mutex::scoped_lock scoped_lock(lock);
    time_of_last_message_ = this->world->GetSimTime();
    x_ = cmd_msg->linear.x;
    y_ = cmd_msg->linear.y;
    rot_ = cmd_msg->angular.z;
  }

  void ObjectControllerPlugin::QueueThread() {
    static const double timeout = 0.01;
    while (alive_ && rosnode_->ok()) {
      queue_.callAvailable(ros::WallDuration(timeout));
    }
  }

  void ObjectControllerPlugin::getSimpleMap(
      const nav_msgs::OccupancyGrid::ConstPtr& map) {

    ROS_DEBUG("OCPlugin (%s) has received a map.", 
        this->modelNamespace.c_str());

    map_.header = map->header;

    map_.info.map_load_time = map->info.map_load_time;
    map_.info.resolution = map->info.resolution;
    map_.info.width = map->info.width;
    map_.info.height = map->info.height;

    // Get the map origin in global space
    // useful for multi_level_map
    tf::TransformListener listener;
    geometry_msgs::PoseStamped pose_in, pose_out;
    pose_in.header = map->header;
    pose_in.pose = map->info.origin;

    map_.info.origin = pose_in.pose;
    // If the map is not in the gazebo global frame, acquire the transformation
    if (map->header.frame_id != this->globalFrame && 
        "/" + map->header.frame_id != this->globalFrame &&
        map->header.frame_id != "/" + this->globalFrame) {
      bool transform_available = 
        listener.waitForTransform(map->header.frame_id, 
            this->globalFrame, ros::Time(0), ros::Duration(5.0));
      if (transform_available) {
        ROS_INFO("OCPlugin (%s) Transformation to gazebo global frame acquired",
            this->modelNamespace.c_str());
        listener.transformPose(this->globalFrame, ros::Time(0), pose_in, 
            pose_in.header.frame_id, pose_out);
        map_.info.origin = pose_out.pose;
      } else {
        ROS_ERROR("OCPlugin (%s) Transformation to gazebo global frame failed", 
            this->modelNamespace.c_str());
        ROS_ERROR("OCPlugin (%s)   Failed transform is %s (global) to %s",
            this->modelNamespace.c_str(), this->globalFrame.c_str(),
            map->header.frame_id.c_str());
      }
    }

    // Expand the map out based on the circumscribed model distance
    int expand_pixels = 
      ceil(circumscribed_model_distance_ / map->info.resolution);
    map_.data.resize(map->info.height * map->info.width);
    for (int i = 0; i < (int)map->info.height; ++i) {
      for (int j = 0; j < (int)map->info.width; ++j) {
        int low_i = (i - expand_pixels < 0) ? 0 : i - expand_pixels;
        int high_i = (i + expand_pixels >= (int)map->info.height) ? 
          map->info.height - 1 : i + expand_pixels;
        int max = 0;
        for (int k = low_i; k <= high_i; ++k) {
          int diff_j = 
            floor(sqrtf(expand_pixels * expand_pixels - (i - k) * (i - k)));
          int low_j = (j - diff_j < 0) ? 0 : j - diff_j;
          int high_j = (j + diff_j >= (int)map->info.width) ? 
            map->info.width - 1 : j + diff_j;
          for (int l = low_j; l <= high_j; ++l) {
            if (map->data[k * map->info.width + l] > max) {
              max = map->data[k * map->info.width + l];
            }
          }
        }
        map_.data[i * map->info.width + j] = max;
      }
    }

    pub2_.publish(map_);
    map_available_ = true;

    ROS_DEBUG("OCPlugin (%s) has processed the map.", 
        this->modelNamespace.c_str());
  }

  void ObjectControllerPlugin::publishOdometry(double step_time) {
    ros::Time current_time = ros::Time::now();
    std::string odom_frame = tf::resolve(tf_prefix_, "odom");
    std::string base_footprint_frame = 
      tf::resolve(tf_prefix_, "base_footprint");

    // getting data for base_footprint to odom transform
    math::Pose pose = this->parent->GetWorldPose();

    tf::Quaternion qt(pose.rot.x, pose.rot.y, pose.rot.z, pose.rot.w);
    tf::Vector3 vt(pose.pos.x, pose.pos.y, pose.pos.z);

    tf::Transform base_footprint_to_odom(qt, vt);
    transform_broadcaster_->sendTransform(
        tf::StampedTransform(base_footprint_to_odom, current_time, odom_frame,
            base_footprint_frame));

    // publish odom topic
    odom_.pose.pose.position.x = pose.pos.x;
    odom_.pose.pose.position.y = pose.pos.y;

    odom_.pose.pose.orientation.x = pose.rot.x;
    odom_.pose.pose.orientation.y = pose.rot.y;
    odom_.pose.pose.orientation.z = pose.rot.z;
    odom_.pose.pose.orientation.w = pose.rot.w;
    odom_.pose.covariance[0] = 0.00001;
    odom_.pose.covariance[7] = 0.00001;
    odom_.pose.covariance[14] = 1000000000000.0;
    odom_.pose.covariance[21] = 1000000000000.0;
    odom_.pose.covariance[28] = 1000000000000.0;
    odom_.pose.covariance[35] = 0.001;

    // get velocity in /odom frame
    math::Vector3 linear;
    // Getting values from the worlds model in gazebo instead of supplied
    // velocites as a simple means of error correction
    linear.x = (pose.pos.x - last_odom_pose_.pos.x) / step_time;
    linear.y = (pose.pos.y - last_odom_pose_.pos.y) / step_time;
    boost::mutex::scoped_lock scoped_lock(lock);
    if (rot_ > M_PI / step_time) { 
      // we cannot calculate the angular velocity correctly
      odom_.twist.twist.angular.z = rot_;
    } else {
      float last_yaw = last_odom_pose_.rot.GetYaw();
      float current_yaw = pose.rot.GetYaw();
      while (current_yaw < last_yaw - M_PI) current_yaw += 2*M_PI;
      while (current_yaw > last_yaw + M_PI) current_yaw -= 2*M_PI;
      float angular_diff = current_yaw - last_yaw;
      odom_.twist.twist.angular.z = angular_diff / step_time;
    }
    last_odom_pose_ = pose;

    // convert velocity to child_frame_id (aka base_footprint)
    float yaw = pose.rot.GetYaw();
    odom_.twist.twist.linear.x = cosf(yaw) * linear.x + sinf(yaw) * linear.y;
    odom_.twist.twist.linear.y = cosf(yaw) * linear.y - sinf(yaw) * linear.x;

    odom_.header.stamp = current_time;
    odom_.header.frame_id = odom_frame;
    odom_.child_frame_id = base_footprint_frame;

    pub_.publish(odom_);
  }

  // Update the data in the interface
  void ObjectControllerPlugin::writePositionData(double step_time) {
    // move the simple model manually
    if (map_available_) {

      boost::mutex::scoped_lock scoped_lock(lock);
      float dr = x_ * step_time;
      float dy = y_ * step_time;
      float da = rot_ * step_time;

      if (fabs(dr) < 1e-3 && fabs(dy) < 1e-3 && fabs(da) < 1e-3) {
        // Don't keep overwriting in case the user wants to try and move a
        // stationary object. This plugin moving the object around can create
        // some problems
        return;
      }

      math::Pose orig_pose = this->parent->GetWorldPose();
      math::Pose new_pose = orig_pose;
      new_pose.pos.x = orig_pose.pos.x + 
        dr * cos(orig_pose.rot.GetYaw()) - dy * sin(orig_pose.rot.GetYaw());
      new_pose.pos.y = orig_pose.pos.y + 
        dr * sin(orig_pose.rot.GetYaw()) + dy * cos(orig_pose.rot.GetYaw());
      new_pose.rot.SetFromEuler(math::Vector3(0,0,orig_pose.rot.GetYaw() + da));

      // Check if the new pose can be allowed
      int x_pxl = 
        (new_pose.pos.x - map_.info.origin.position.x) / map_.info.resolution;
      int y_pxl = 
        (new_pose.pos.y - map_.info.origin.position.y) / map_.info.resolution;

      if (x_pxl < 0 || x_pxl >= (int)map_.info.width ||
          y_pxl < 0 || y_pxl >= (int)map_.info.height ||
          (map_.data[y_pxl * map_.info.width + x_pxl] < 50)) {
        this->parent->SetWorldPose(new_pose);
        math::Vector3 zeros(0,0,0);
        this->parent->SetLinearVel(zeros);
        this->parent->SetLinearAccel(zeros);
        this->parent->SetAngularVel(zeros);
        this->parent->SetAngularAccel(zeros);
      } else {
        ROS_DEBUG_THROTTLE(2.0, "OCPlugin (%s) is preventing the object from "
            "running into a wall.", this->modelNamespace.c_str());
      } 
    } else {
      ROS_WARN_THROTTLE(2.0, "OCPlugin (%s) has not received a map. " 
          "Cannot move the object", this->modelNamespace.c_str());
    }

  }

  GZ_REGISTER_MODEL_PLUGIN(ObjectControllerPlugin)
}