darwin_odom_twist_alg_node.cpp

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#include "darwin_odom_twist_alg_node.h"

DarwinOdomTwistAlgNode::DarwinOdomTwistAlgNode(void) :
  algorithm_base::IriBaseAlgorithm<DarwinOdomTwistAlgorithm>()
{
  //init class attributes if necessary
  this->loop_rate_ = 100;//in [Hz]
  this->yaw_angle=0.0;
  this->is_first_msg_=true;

  this->public_node_handle_.param<std::string>("tf_prefix",    this->tf_prefix_,     "");
  this->public_node_handle_.param<std::string>("odom_id",      this->odom_id_,      "odom" );
  this->public_node_handle_.param<std::string>("base_link_id", this->base_link_id_, "base_link" );
  this->public_node_handle_.param<bool>       ("publish_tf",   this->publish_tf_,   true  );

  // push down frame ids if necessary
  if( !this->tf_prefix_.empty() )
  {
    this->odom_id_      = this->tf_prefix_ + "/" + this->odom_id_;
    this->base_link_id_ = this->tf_prefix_ + "/" + this->base_link_id_;
  }

  // [init publishers]
  this->odom_publisher_ = this->public_node_handle_.advertise<nav_msgs::Odometry>("odom", 100);

  // [init subscribers]
  this->input_twist_subscriber_ = this->public_node_handle_.subscribe("input_twist", 100, &DarwinOdomTwistAlgNode::input_twist_callback, this);
  // [init services]

  // [init clients]

  // [init action servers]

  // [init action clients]
}

DarwinOdomTwistAlgNode::~DarwinOdomTwistAlgNode(void)
{
  // [free dynamic memory]
}

void DarwinOdomTwistAlgNode::mainNodeThread(void)
{
  ros::Time current_time=ros::Time::now();
  geometry_msgs::TransformStamped odom_trans_msg;
  double dt = (current_time - this->last_time_).toSec();
  static int delay=10;

  this->input_twist_mutex_.enter();
  this->yaw_angle+=this->twist_.twist.angular.z*dt;
  //since all odometry is 6DOF we'll need a quaternion created from yaw
  geometry_msgs::Quaternion odom_quat = tf::createQuaternionMsgFromYaw(this->yaw_angle);

  //update transform message
  this->transform_.translation.x += this->twist_.twist.linear.x*dt*cos(this->yaw_angle);
  this->transform_.translation.y += this->twist_.twist.linear.x*dt*sin(this->yaw_angle);
  this->transform_.translation.z += 0.0;
  this->transform_.rotation       = odom_quat;

  //update pose
  this->pose_.pose.position.x += this->twist_.twist.linear.x*dt*cos(this->yaw_angle);
  this->pose_.pose.position.y += this->twist_.twist.linear.x*dt*sin(this->yaw_angle);
  this->pose_.pose.position.z += 0.0;
  this->pose_.pose.orientation = odom_quat;
  this->input_twist_mutex_.exit();

  //update last time
  this->last_time_ = current_time;

  //send the transform
  if(this->publish_tf_)
  {
    //first, we'll publish the transform over tf
    odom_trans_msg.header.stamp    = current_time;
    odom_trans_msg.header.frame_id = this->odom_id_;
    odom_trans_msg.child_frame_id  = this->base_link_id_;
    odom_trans_msg.transform       = this->transform_;
 
    if(delay==0)
      this->odom_broadcaster_.sendTransform(odom_trans_msg);
  }
 
  //next, we'll publish the odometry message over ROS
  this->Odometry_msg_.header.stamp     = current_time;
  this->Odometry_msg_.header.frame_id  = this->odom_id_;
  this->Odometry_msg_.child_frame_id   = this->base_link_id_;
  this->Odometry_msg_.pose             = this->pose_;
  this->Odometry_msg_.twist            = this->twist_;

  //publish the message
  if(delay==0)
    this->odom_publisher_.publish(this->Odometry_msg_);
  delay--;
  if(delay<0) 
    delay=10;
}

/*  [subscriber callbacks] */
void DarwinOdomTwistAlgNode::input_twist_callback(const geometry_msgs::Twist::ConstPtr& msg) 
{ 
  if(this->is_first_msg_)
  {
    this->is_first_msg_ = false;
    this->last_time_=ros::Time::now();
  }
  // copy the input twist
  this->input_twist_mutex_.enter();
  this->twist_.twist.linear.x  = msg->linear.x;
  this->twist_.twist.linear.y  = msg->linear.y;
  this->twist_.twist.linear.z  = msg->linear.z;
  this->twist_.twist.angular.x = msg->angular.x;
  this->twist_.twist.angular.y = msg->angular.y;
  this->twist_.twist.angular.z = msg->angular.z;
  this->input_twist_mutex_.exit();
}

/*  [service callbacks] */

/*  [action callbacks] */

/*  [action requests] */

void DarwinOdomTwistAlgNode::node_config_update(Config &config, uint32_t level)
{
  this->alg_.lock();

  this->alg_.unlock();
}

void DarwinOdomTwistAlgNode::addNodeDiagnostics(void)
{
}

/* main function */
int main(int argc,char *argv[])
{
  return algorithm_base::main<DarwinOdomTwistAlgNode>(argc, argv, "darwin_odom_twist_alg_node");
}