barrybear's profile - activity

Hello there! I am currently trying to fuse the odometry messages from the ROSARIA and visual odometry messages from viso2_ros libraries using the robot_pose_ekf. However, I seem to always encounter an error of where the covariance matrix is zero.

I am still a beginner, and I have read a little about covariance. I would like to know how to implement the covariance or include some appropriate values into the matrix in order for the robot_pose_ekf to work succesfully..

Hello all!

I am using a Pioneer P3AT to apply map building and autonomous navigation using a hokuyo laser with GMapping and Navigation stack. However for the autonomous navigation part, I was success to allow a random selection of unknown cell and move the robot to that cell. After actually applying this to the robot, I realized that the robot seems to be moving in a circle and always stay at the same area.

I thought that if i could obtain the coordinates of the new area being built while mapping, I could direct the robot to move to that area instead..but I don't know if its possible as subscribing the /map topic could publish random points?

Hello all,

I've followed the tutorial here http://www.ros.org/wiki/navigation/Tutorials/RobotSetup and also checked the website for similar questions but I am still quite confused and unable to produce the result I need.

I'm hooking up GMapping to the Costmap by setting static_map: true for global_costmap_params.yaml and static_map: falase for local_cost_map_params. However I wish to allow the robot, Pionneer3-AT to auto navigate itself in that environment. I thought of pointing the 2D Nav Goal to the unknown space from local_costmap but I've received errors and there's no reaction from the robot whatsoever.

Error from Costmap launch

[ERROR] [1371710574.377069274]: Client [/rostopic_25335_1371710566077] wants topic /move_base/local_costmap/unknown_space to have datatype/md5sum [geometry_msgs/PoseStamped/d3812c3cbc69362b77dc0b19b345f8f5], but our version has [nav_msgs/GridCells/b9e4f5df6d28e272ebde00a3994830f5]. Dropping connection.

Error from RVIZ

[ERROR] [1371710524.998325539]: md5sum mismatch making local subscription to topic /move_base/local_costmap/unknown_space. [ERROR] [1371710524.998429812]: Subscriber expects type nav_msgs/GridCells, md5sum b9e4f5df6d28e272ebde00a3994830f5 [ERROR] [1371710524.998484870]: Publisher provides type geometry_msgs/PoseStamped, md5sum d3812c3cbc69362b77dc0b19b345f8f5

rostopic echo /move_base/local_costmap/unknown_space would also most of the time not return anything.

I also applied unknown_cost_value: 255 and track_unknown_space: true to the costmap_common_params

It'll be great to get some help to achieve autonavigation in an unknown environment.

** EDIT 1 The errors were eliminated by setting static_map: false for global_costmap. However, there doesn't seem to be any path planning occuring. No errors were found in rxgraph and roswtf too.

** EDIT 2 The global_costmap_params.yaml has settings of static_map: false and rolling_window:true.

I've created a simple publisher and subscriber to subscribe to nav_msgs/GridCells on topic move_base/local_costmap/unknown_space and publish geometry_msgs/PoseStamped on topic /move_base_simple/goal. Since there are a bunch of coordinates of unknown space, a random coordinate is chosen.

The basic ROS tutorial for writing a subscriber/publisher should be referred to as an example.

Yeap I did, it isn't too bad. Another sensor source would be a laser range scanner, Hokuyo URG-04LX-UG01.

Hello all!

I've been conducting some exploration and mapping indoors using GMapping. However, I realize that as the robot moves and builds the map, certain areas of the map changes as the robot moves and worsen. I have a hunch that it could be the odometry data, but I need some verification of it. Also, would love to know what are the ways to improve the mapping and reduce any errors caused.

The robot was most of the time moving and turning at 0.1 m/s. The maximum speed I set was 0.2 m/s. Number of particles for the map is about 100.

The image above shows the two corridors not being parallel and at the bottom of the map being distorted.

Comparing this image:

and this image:

just a lil difference in the robot's position caused so much error at the robot's initial position (in the first picture).

Overall map built:

Hello all!

I seem to be having a slight issue, whereby the Pioneer 3-AT doesn't seem to produce a complete RobotModel. I am currently using the p2os_urdf package to initiate this RobotModel. Even initiating the launch file for a pioneer3dx seem to produce the same issue..

Any help would be very much appreciated!

I've actually tried the package with another laptop and the robot model's perfect! Must have been the drivers of my graphic card..may have had some problem earlier. Thanks!

Hello!

I am using a Pioneer 3-AT and ROS Groovy, and successfully using the P2OS_DRIVER to connect to the robot. Also being able to control using the keyboard with the TELE_OP launch files.

However, when i execute rosrun p2os_dashboard p2os_dashboard, this error appears and I've checked the p2os source files and I can't seem to figure out. Would appreciate the help!

from p2os_driver.msg import BatteryState, MotorState

ImportError: No module named msg

Hey all, I seem to be having this problem whenever using rosdep

ERROR: Rosdep experienced an internal error: [Errno 13] Permission denied: '/home/barrybear/.ros/rosdep/sources.cache/index' Please go to the rosdep page [1] and file a bug report with the stack trace below. [1] : http://www.ros.org/wiki/rosdep

Traceback (most recent call last):
File "/usr/lib/pymodules/python2.7/rosdep2/main.py", line 116, in rosdep_main exit_code = _rosdep_main(args) File "/usr/lib/pymodules/python2.7/rosdep2/main.py", line 257, in _rosdep_main return _package_args_handler(command, parser, options, args) File "/usr/lib/pymodules/python2.7/rosdep2/main.py", line 331, in _package_args_handler lookup = _get_default_RosdepLookup(options) File "/usr/lib/pymodules/python2.7/rosdep2/main.py", line 107, in _get_default_RosdepLookup verbose=options.verbose) File "/usr/lib/pymodules/python2.7/rosdep2/sources_list.py", line 501, in create_default sources = load_cached_sources_list(sources_cache_dir=sources_cache_dir, verbose=verbose) File "/usr/lib/pymodules/python2.7/rosdep2/sources_list.py", line 419, in load_cached_sources_list with open(cache_index, 'r') as f: IOError: [Errno 13] Permission denied: '/home/barrybear/.ros/rosdep/sources.cache/index'

Whenever I try to apply sudo rosdep, I'll obtain this error:

ERROR: Rosdep cannot find all required resources to answer your query Missing resource scan_tools

Can anyone please help me with a fix? Thanks :)

Oh okay, I was just thinking if there is a way to extract out the coordinates of the new area of the map being created

Yeah I'm wondering if there is way to do so autonomously.. Cant seem to figure out despite subscribing to the /map and /map_metadata topic