Checked if the path is empty when checking if the goal has been reached.

src/ackermann_planner_ros.cpp

@@ -255,6 +255,12 @@ bool AckermannPlannerROS::isGoalReached(void)
     ROS_ERROR("AckermannPlannerROS: could not get local plan");
     return false;
   }
+  if(transformed_plan.empty()) 
+  {
+    ROS_WARN_NAMED("AckermannPlannerROS", "Received an empty transformed plan.");
+    return false;
+  }
+ 
   odom_helper_.get_odom(odom);
   if(planner_util_.last_path())
   {