[ros-users] Navigation stack: robot starts rotating upon recieving goal

Mon May 17 17:45:42 UTC 2010

Hitesh,

Planning normally fails for one of two reasons:

1) There is an obstacle, or a perceived obstacle, that causes planning to
fail. Look at the move_base_node/global_costmap/obstacles and
move_base_node/global_costmap/inflated_obstacles topics in rviz to help
debug this. Do you see any obstacles show up at all? Do you see the path
blocked by the inflated obstacles? Also, visualize the goal that you're
sending to move_base... check out the move_base_node/current_goal topic. You
can find more information on using rviz with the navigation stack here:
http://www.ros.org/wiki/navigation/Tutorials/Using%20rviz%20with%20the%20Navigation%20Stack

2) There is unknown space that prevents planning from succeeding. Look at
the move_base_node/global_costmap/unknown_space topic in rviz. Do you see
unknown space blocking the robot's path?

Also, a couple of suggestions from looking at your configuration:

1) You should probably set "raytrace_range" to be greater than
"obstacle_range," otherwise you may have obstacles that do not clear out of
the costmap as you'd expect.

2) If you're going to use a global_costmap that works in the odom frame,
you'll probably want to set the "rolling_window" parameter to true.
Otherwise, the robot will reach the edge of the map and not be able to
continue.

Hope this helps,

Eitan

On Sat, May 15, 2010 at 5:35 AM, hitesh dhiman <hitesh.dhiman.1988 at gmail.com
> wrote:

> Hi all,
> I've been trying to troubleshoot the robot and running navigation stack on
> it. Earlier atleast the path was being planed and published, but we decided
> to migrate to a different laptop with a graphics card.
> Now, our files are  the same, the tf's are also same, I've attached the
> file. ROS installation on the new laptop was done through svn, and that's
> the only change.
> The odometry is transformed as follows:
> odom_broadcaster.sendTransform((odom.pose.pose.position.x,
> odom.pose.pose.position.y ,
> odom.pose.pose.position.z),tf.transformations.quaternion_from_euler(0,0,float(odo_returned[2]*0.001534)),rospy.Time.now(),"base_link","odom")
>
>
> odo_returned[2] here is an element of a python list, and contains the
> odometry data with yaw values, that have a conversion factor of .001534.
>
> The laser is being transformed as follows:
> broadcaster.sendTransform(tf::StampedTransform(tf::Transform(tf::Quaternion(0,
> 0, 0, 1), tf::Vector3(0.0, 0.0, 0.2)),ros::Time::now(),"/base_link",
> "/laser"));
>
> The values for move_base parameters are also shown below:
> base_local_planner_params.yaml:
> TrajectoryPlannerROS:
>   transform_tolerance: 0.3
>   sim_time: 1.7
>   sim_granularity: 0.05
> # dwa: true
>   vx_samples: 3
>   vtheta_samples: 20
>   max_vel_x: 1
>   min_vel_x: 0.2
>   max_rotational_vel: 1.0
>   min_in_place_rotational_vel: 0.4
>   xy_goal_tolerance: 0.2
>   yaw_goal_tolerance: 0.05
>   goal_distance_bias: 0.8
>   path_distance_bias: 0.6
>   occdist_scale: 0.5
> # occdist_scale: 0.05
>   heading_lookahead: 0.325
>   oscillation_reset_dist: 0.05
>   acc_limit_th: 3.2
>   acc_limit_x: 2.5
>   acc_limit_y: 2.5
>   holonomic_robot: false
>
> costmap_common_params.yaml:
> obstacle_range: 2.5
> raytrace_range: 1.0
> footprint: [[-0.2, -0.2], [0.2, -0.2], [0.2, 0.2], [-0.2, 0.2]]
> #robot_radius: 0.4
> inflation_radius: 0.2
>
> observation_sources: laser_scan_sensor
>
> laser_scan_sensor: {sensor_frame: laser, data_type: LaserScan, topic: /scan
> , marking: true, clearing: true}
>
> global_costmap_params.yaml:
> global_costmap:
>   global_frame: /odom
>   robot_base_frame: /base_link
>   update_frequency: 5.0
>   publish_frequency: 2.0
>   static_map: false
>
> 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
>
> I'm using simple_navigation_goals, and giving a goal of x=2 m and w = 1 in
> /odom frame.
>
> On passing the goal, the robot starts rotating about the centre, and gives
> the following in the status:
> Failed to find a valid plan. Even after executing recovery behaviors.
> No messages for any global or local plan are being published. We also tried
> to start with running the robot straight, and then giving it a goal to see
> if anything works. But the velocity commands were still being pulished as (x
> =0, theta = 57), which means it still wants to rotate.
> The action server reports that the The base failed to move forward 2 meter
> for some reason.
>
> The test is being done in a corridor, approx 8-10 feet wide with no
> obstacles, so there is no reason why the plan should fail.
>
> Any help or hints would be greatly appreciated. I've out all the possible
> problems i thought could exist, but no luck so far.
> --
> Regards,
> Hitesh Dhiman
> Electrical Engineering
> National University of Singapore
>
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