{"action":"created","issue":{"url":"https://api.github.com/repos/koide3/hdl_graph_slam/issues/25","repository_url":"https://api.github.com/repos/koide3/hdl_graph_slam","labels_url":"https://api.github.com/repos/koide3/hdl_graph_slam/issues/25/labels{/name}","comments_url":"https://api.github.com/repos/koide3/hdl_graph_slam/issues/25/comments","events_url":"https://api.github.com/repos/koide3/hdl_graph_slam/issues/25/events","html_url":"https://github.com/koide3/hdl_graph_slam/issues/25","id":351173161,"node_id":"MDU6SXNzdWUzNTExNzMxNjE=","number":25,"title":"Map odom transforms and mapping an unflat surface","user":{"login":"ashammaa","id":42379077,"node_id":"MDQ6VXNlcjQyMzc5MDc3","avatar_url":"https://avatars3.githubusercontent.com/u/42379077?v=4","gravatar_id":"","url":"https://api.github.com/users/ashammaa","html_url":"https://github.com/ashammaa","followers_url":"https://api.github.com/users/ashammaa/followers","following_url":"https://api.github.com/users/ashammaa/following{/other_user}","gists_url":"https://api.github.com/users/ashammaa/gists{/gist_id}","starred_url":"https://api.github.com/users/ashammaa/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ashammaa/subscriptions","organizations_url":"https://api.github.com/users/ashammaa/orgs","repos_url":"https://api.github.com/users/ashammaa/repos","events_url":"https://api.github.com/users/ashammaa/events{/privacy}","received_events_url":"https://api.github.com/users/ashammaa/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":3,"created_at":"2018-08-16T11:55:36Z","updated_at":"2018-09-04T16:16:07Z","closed_at":null,"author_association":"NONE","body":"Hi @koide3 ,\r\n\r\nI have installed you Hdl_graph_slam and Hdl_localizations packages and have been implementing them on a Clearpath Husky robot and have a couple of questions:\r\n\r\nHdl_graph_slam:\r\n\r\n1- I recorded a rosbag file of the area I want to map (I am using a VLP-16 lidar and an RTK GPS for scan-matching error correction) and launched the hdl_graph_slam launch file. However, during the mapping process, the odom frame jumps around, while only the map frame stays fixed, the 0,0, 0 of the map frame is the starting point of the mapping process. Also, while the map being built represents the area I am mapping correctly, as the map is being built, the map kind of sinks in the negative z-direction of the map frame axis. I have attached a screen shot, which hopefully better explains what I am talking about. Do you have any idea why these things are happening? Should not the map frame and the odom frame stay fixed to where the mapping process started?\r\n\r\n![map odom transform](https://user-images.githubusercontent.com/42379077/44207610-a1e9f280-a166-11e8-8c32-feff5091b790.png)\r\n\r\n2- I sent you an email to: koide@aisl.cs.tut.ac.jp from my email: as243@aub.edu.lb and would really appreciate it if you can send me a copy of your paper, as I would be strictly using it for educational purposes and to better understand the algorithm you implemented in these packages.\r\n\r\n3- I have been mainly using the hdl_graph_slam outdoors on unflat surfaces and wanted to ask you about the limitations of the algorithm if I am implementing it with a gps while turning off the floor_detection_nodelet. How accurate is the algorithm? and what are some of the parameters I can tune to get better results?\r\n\r\nHdl_localization:\r\n\r\nAfter obtaining a map of the area, I am implementing the hdl_localization package to localize my Husky robot within this map. However, I wanted to ask about how should I go around fixing my transform tree, which as of right now is consisted of a base_link which is the parent frame for the remaining components of the robot, including the velodyne frame that I am using and another transform tree consisting of the map parent frame and the velodyne child frame. Attached is a screenshot of my transform trees:\r\n\r\n[frames.pdf](https://github.com/koide3/hdl_graph_slam/files/2293647/frames.pdf)\r\n\r\nBelow is the error I am getting:\r\n\r\n`ERROR TF re-parenting contention:\r\n * reparenting of [velodyne] to [map] by [/velodyne_nodelet_manager]\r\n * reparenting of [velodyne] to [sensor_arch_mount_link] by [/robot_state_publisher]\r\n\r\nERROR TF multiple authority contention:\r\n * node [/velodyne_nodelet_manager] publishing transform [velodyne] with parent [map] already published by node [/robot_state_publisher]\r\n * node [/robot_state_publisher] publishing transform [velodyne] with parent [sensor_arch_mount_link] already published by node [/velodyne_nodelet_manager]`\r\n\r\nHow can I fix the transform tree so that the map frame publishes to the base_link frame, which has as one of its child frames the velodyne frame for the VLP-16? I tried to insert \"<param name=\"child_frame_id\" value=\"base_link\" />\"  under the globalmap_server_nodelet and the localization_nodelet (not at the same time), however, that did not work. \r\n\r\nApologies for the lengthy message and hope my questions are well defined!\r\n\r\nThanks - Abed\r\n"},"comment":{"url":"https://api.github.com/repos/koide3/hdl_graph_slam/issues/comments/418428920","html_url":"https://github.com/koide3/hdl_graph_slam/issues/25#issuecomment-418428920","issue_url":"https://api.github.com/repos/koide3/hdl_graph_slam/issues/25","id":418428920,"node_id":"MDEyOklzc3VlQ29tbWVudDQxODQyODkyMA==","user":{"login":"ashammaa","id":42379077,"node_id":"MDQ6VXNlcjQyMzc5MDc3","avatar_url":"https://avatars3.githubusercontent.com/u/42379077?v=4","gravatar_id":"","url":"https://api.github.com/users/ashammaa","html_url":"https://github.com/ashammaa","followers_url":"https://api.github.com/users/ashammaa/followers","following_url":"https://api.github.com/users/ashammaa/following{/other_user}","gists_url":"https://api.github.com/users/ashammaa/gists{/gist_id}","starred_url":"https://api.github.com/users/ashammaa/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ashammaa/subscriptions","organizations_url":"https://api.github.com/users/ashammaa/orgs","repos_url":"https://api.github.com/users/ashammaa/repos","events_url":"https://api.github.com/users/ashammaa/events{/privacy}","received_events_url":"https://api.github.com/users/ashammaa/received_events","type":"User","site_admin":false},"created_at":"2018-09-04T16:16:07Z","updated_at":"2018-09-04T16:16:07Z","author_association":"NONE","body":"Hello @koide3,\r\n\r\nWhen I am using the hdl_localization package, for the motion models used in the prediction step of the Unscented Kalman Filter, both models (process noise or IMU) does not lead to the converging of the UKF. I believe that is because my Clearpath Husky robot has a different motion model and integrating the acceleration using the IMU is proven to be too noisy. For such a case, the only way to improve the localization would be to modify the code to fuse the information of the wheel odometry? Or is there another way to improve localization as the package is currently constructed?   \r\n\r\nThanks again for your time!!! \r\n\r\nRegards, \r\n\r\nAbed"}}
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