Safdar,

Do you see any obstacles appear in-front of the robot in rviz when it starts
to move backwards? It should only back up when it has a legal plan to go
forward but cannot find a local trajectory that enables it to move. For the
robot to back up for a large distance, I'd expect that it would have to
continuously see an obstacle in front of it.

Looking at the following topics in rviz should help:

move_base/local_costmap/obstacles
move_base/local_costmap/inflated_obstacles
move_base/local_costmap/unknown_space

Hope this helps,

Eitan

On Fri, Sep 24, 2010 at 3:40 AM, safdar_zaman <safdaraslam@yahoo.com> wrote:

>
> Hi dear all,
> During Path planning of Poineer P3-DX I bring up everything,
> roscore,ROSARIA,sicklms,mapserver,amcl_diff.launch,move_base.launch and
> rviz. Everything seems fine until I give the goal by pressing 2D Nav Goal
> button in rviz. I give goal to move Robot one meter forward.It shows the
> correct path to our goal on rviz avoiding obstacles. but after a while when
> Robot starts moving on the goal it always moves backwards slowly and does
> not stop. Somewhere stops for a nanosecond and then continues moving
> backwards again,I switch it off for stopping. Can any one help to fix it ?
> I use the tutorial http://www.ros.org/wiki/navigation/Tutorials/RobotSetup
> :
> with following files:
>
> move_base.launch:
> <launch>
>  <node pkg="move_base" type="move_base" respawn="false" name="move_base"
> output="screen">
>    <rosparam
>
> file="/opt/ros/cturtle/stacks/ros_tutorials/poineer_zaman/costmap_common_params.yaml"
> command="load" ns="global_costmap" />
>    <rosparam
>
> file="/opt/ros/cturtle/stacks/ros_tutorials/poineer_zaman/costmap_common_params.yaml"
> command="load" ns="local_costmap" />
>    <rosparam
>
> file="/opt/ros/cturtle/stacks/ros_tutorials/poineer_zaman/local_costmap_params.yaml"
> command="load" />
>    <rosparam
>
> file="/opt/ros/cturtle/stacks/ros_tutorials/poineer_zaman/global_costmap_params.yaml"
> command="load" />
>    <rosparam
>
> file="/opt/ros/cturtle/stacks/ros_tutorials/poineer_zaman/base_local_planner_params.yaml"
> command="load" />
>  </node>
> </launch>
> ----------------------
> costmap_common_params.yaml:
> obstacle_range: 2.5
> raytrace_range: 3.0
> footprint: [[0.3, 0.3], [0.3, -0.3], [-0.3, -0.3], [-0.3, 0.3]]
> #robot_radius: ir_of_robot
> inflation_radius: 0.55
>
> transform_tolerance : 0.5
> observation_sources: laser_scan_sensor
> laser_scan_sensor: {sensor_frame: laser, data_type: LaserScan, topic: scan,
> marking: true, clearing: true}
> --------------
> local_costmap_params.yaml:
> local_costmap:
>  global_frame: odom
>  robot_base_frame: base_link
>  update_frequency: 5.0
>  publish_frequency: 2.0
>  static_map: false
>  rolling_window: true
>  width: 6.0
>  height: 6.0
>  resolution: 0.05
> -------------------------
> global_costmap_params.yaml:
> global_costmap:
>  global_frame: /map
>  robot_base_frame: base_link
>  update_frequency: 5.0
>  static_map: true
> ---------------------------
> base_local_planner_params.yaml:
> TrajectoryPlannerROS:
>  max_vel_x: 0.45
>  min_vel_x: 0.1
>  max_rotational_vel: 1.0
>  min_in_place_rotational_vel: 0.4
>
>  acc_lim_th: 3.2
>  acc_lim_x: 2.5
>  acc_lim_y: 2.5
>
>  holonomic_robot: false
> ------------------------------
> thanks in advance
> --
> View this message in context:
> http://ros-users.122217.n3.nabble.com/Poineer-s-Path-Navegation-tp1573121p1573121.html
> Sent from the ROS-Users mailing list archive at Nabble.com.
> _______________________________________________
> ros-users mailing list
> ros-users@code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>