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2021-09-30 09:55:24 -0500 | commented question | is there a standalone steering package for car-like robot? Nah, that one is for creating a steering command when the desired speed and rotation are calculated. What I need is an a |
2021-09-21 15:13:37 -0500 | asked a question | is there a standalone steering package for car-like robot? is there a standalone steering package for car-like robot? tl;dr is there a ready ROS\third-party package that takes in |
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2019-04-08 01:17:41 -0500 | marked best answer | costmap_2d: how to publish local costmap to topic I'm running costmap_2d with PointCloud2 feed from a 3D lidar as the only source. Lidar points are preliminary filtered, the ground is mostly segmented out. It is used as a singular source for the singular plugin of type ObstacleLayer. As I'm using the output occupancy grid for use with home-made custom code, I would like to have a small portion of costmap near the robot position be published after every update as OccupancyGrid. I guess this is what local_costmap settings can be used for, right? Well, false. The setup works the same way with and without additional YAML file for the local costmap. Even worse, I cannot get the full costmap to be published every step. The /costmap/costmap topic is being published once at the start, all the rest time only costmap/costmap_update are published. This is happening despite always_send_full_costmap: true in the config. What and where should I write to get instant local occupancy grid published? Below are my two YAML files and the portion in the launchfile where I run the costmapping node. I'm working in Xubuntu 16.04, ROS Kinetic. in the launchfile: costmap_common_voxel_params.yaml: local_costmap_quan_params.yaml: |
2019-03-01 12:35:28 -0500 | marked best answer | costmap_2d marking threshold I'm running costmap_2d with PointCloud2 feed from a 3D lidar as the only source. Lidar points are preliminary filtered, the ground is mostly segmented out. It works fine with both ObstacleLayer and VoxelLayer, marking and clearing. The problem is: I want to set the marking threshold, so that a single lidar point does not immediately mark the cell as occupied. Ideally, I want the lidar observations to have some short but finite lifetime, and the cells to be marked only if they accumulate, say, 5 points at a single moment of time. And here the troubles begin. 1) as I understood, the mark_threshold parameter only works for voxel layer. Is that right? If yes, why? it makes the same perfect sense for 2d occupancy grid. 2) for the voxel layer I managed to employ the mark_threshold, but setting it to anything greater than 0.5 makes the costmap not marking anything, save for a few cells. There is no clear and concise explanation of how this thresholding works for filling in the occupancy grid, and the documentation even contradicts itself on some occasions. Workable configs provided by people in questions puzzle me (like, mark_threshold:9 ?). Could anyone please explain how do I achieve desired behaviour? The YAML config and launch file are below. Xubuntu 16.04, ROS Kinetic. in the launchfile: costmap_common_voxel_params.yaml: |
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2018-07-11 07:48:21 -0500 | marked best answer | robot_localization: enhance local positioning with IMU I'm testing sensor fusion with robot_localization package. I've got a small wheeled robot with an xSense IMU and a quasi-UWB local positioning system. The local positioning consists of two mounted ultrasonic beacons, each is separately localized against several static beacons spread around the room. The system is rather precise: manufacturer reports 2 cm standard deviation, and it's believable. But the update rate is low (around 1 Hz), and the beacons report only position, no orientation. As the robot moves on the flat floor, I use relative position of two beacons to calculate robot position and 2D yaw (dumb middle point for position, dumb relative vector for orientation). The result is accurate, except for the position jumps between updates, and remarkable yaw jitter. I try to use IMU data and robot_localization to provide smooth pose estimation between updates. As for now, my setup is as follows:
Everything is up and running, but the result is far from desired. Filtered odometry follows the constructed pose closely: after each position jump (=update) the filtered pose drifts slowly towards new position for half a second, then jumps to new position altogether. Questions: 1) Could anyone hint me about what parameters I should try to tweak to achieve smooth continuous movement of filtered pose? 2) Is there a ROS functionality to calculate robot pose from position of two mounted beacons? Say, I write static tf transforms from base_link to the two beacons' hardpoints, and ROS calculates the robot position/orientation for me, possibly with some cool Kalman magic? Then, of course, feeds it into the EKF node. Below are the YAML parameter files for my EKF nodes. Note that I use 2d mode for both, but turning it off doesn't change the situation much. IMU-only node: (more) |
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2018-07-10 10:35:42 -0500 | asked a question | ethzasl elevation_mapping behaviour ethzasl elevation_mapping behaviour I am using ethzasl elevation_mapping to build a height map from lidar pointclouds. W |
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2018-02-09 07:27:15 -0500 | answered a question | costmap_2d marking threshold I guess we figured out the mechanics, and, to my opinion, it's not very intuitive. After voxel marking occurs, the mark |
2018-02-07 17:48:28 -0500 | asked a question | costmap_2d: how to publish local costmap to topic costmap_2d: how to publish local costmap to topic I'm running costmap_2d with PointCloud2 feed from a 3D lidar as the on |
2018-02-07 12:17:09 -0500 | asked a question | costmap_2d marking threshold costmap_2d marking threshold I'm running costmap_2d with PointCloud2 feed from a 3D lidar as the only source. Lidar poin |
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2017-09-26 10:15:19 -0500 | edited question | robot_localization: enhance local positioning with IMU robot_localization: enhance local positioning with IMU I'm testing sensor fusion with robot_localization package. I've |
2017-09-26 10:12:18 -0500 | asked a question | robot_localization: enhance local positioning with IMU robot_localization: enhance local positioning with IMU I'm testing sensor fusion with robot_localization package. I've |