void traj_cb(const occgrid_planner::TrajectoryConstPtr & msg) {
     frame_id_ = msg->header.frame_id;
     delay_ = 0.0;
     traj_.clear();
     for (unsigned int i=0;i<msg->Ts.size();i++) {
         traj_.insert(Trajectory::value_type(msg->Ts[i].header.stamp.toSec(), msg->Ts[i]));
     }
     ROS_INFO("Trajectory received");
 }