Hello, I am running a navigation stack and sending goal through coding like below: using namespace eskorta_move; typedef actionlib::SimpleActionClient Client; // Called once when the goal completes void doneCb(const actionlib::SimpleClientGoalState& state, const move_baseResultConstPtr& result) { ROS_INFO("Finished in state [%s]", state.toString().c_str()); ROS_INFO("[X]:%f [Y]:%f [W]: %f",result->base_position.pose.position.x, result->base_position.pose.position.y, result->base_position.pose.orientation.w); ros::shutdown(); } // Called once when the goal becomes active void activeCb() { ROS_INFO("Goal just went active"); } // Called every time feedback is received for the goal void feedbackCb(const move_baseFeedbackConstPtr& feedback) { ROS_INFO("[X]:%f [Y]:%f [W]: %f",feedback->base_position.pose.position.x, feedback->base_position.pose.position.y, feedback->base_position.pose.orientation.w); } int main(int argc, char** argv) { ros::init(argc, argv, "move_eskorta"); Client client("eskorta_base", true); //client.waitForServer(); while(!client.waitForServer(ros::Duration(5.0))){ ROS_INFO("Waiting for the move_base action server to come up"); } eskorta_move::move_baseGoal goal; // [ INFO] [1287828403.230367166]: Setting goal: Frame:/map, Position(-0.423, 1.915, 0.000), Orientation(0.000, 0.000, 0.000, 1.000) = Angle: 0.000 goal.target_pose.header.frame_id = "map"; goal.target_pose.header.stamp = ros::Time::now(); // 1 mtr forward, -2.0 mtr left and 1.0 orientation goal.target_pose.pose.position.x = -0.423; goal.target_pose.pose.position.y = 1.915; goal.target_pose.pose.orientation.w = 1.000; goal.vicinity_range = 0.0; ROS_INFO("Sending goal"); client.sendGoal(goal, &doneCb, &activeCb, &feedbackCb); client.waitForResult(); /* if(client.getState() == actionlib::SimpleClientGoalState::SUCCEEDED){ ROS_INFO("Hooray, the base moved meter forward, %s"); } else{ // client.getResult(); ROS_INFO("The base failed to move forward 1 meter for some reason, %s" );}*/ ros::spin(); return 0; } After running stack, in between i send executable of this code. So as, robot will receive a goal. After that, i get non-stop messages like below, [ INFO] [1287986999.289579675]: Waiting for the move_base action server to come up Map is already received by the Navigation stack. When i try to change the code, Client client("eskorta_base", true); to Client client("move_base", true); then i get an error: [ERROR] [1287987393.000424927]: Client [/move_eskorta] wants topic /move_base/result to have datatype/md5sum [eskorta_move/move_baseActionResult/0ab416b06f38c51e47c9638aa34125b5], but our version has [move_base_msgs/MoveBaseActionResult/1eb06eeff08fa7ea874431638cb52332]. Dropping connection. where, move_base another node running through Navigation stack. Am i missing something? Thanks in advance. - Prasad -- View this message in context: http://ros-users.122217.n3.nabble.com/Actionlib-Server-communication-tp1765659p1765659.html Sent from the ROS-Users mailing list archive at Nabble.com.