gmapping + iRobot Create + Hokuyo laser scanner

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Hello ROS fans,

I have a general question about using slam_gmapping with an iRobot Create and a Hokuyo laser scanner (model URG-04LX-UG01). I understand that the odometry on the Create is a little shaky and I can see this by doing an "out and back" test using odometry alone--the Create ends up quite a ways from the starting point. So now I am trying gmapping using the Brown irobot_create_2_1 driver to provide odometry and the laser scanner set to a 240 degree sweep. I can make some fairly good maps of my apartment but I have noticed a phenomenon that I think I sort of understand and was wondering if I can remedy.

Even after a room has been fairly well mapped out, as the Create continues to move about, the points of the laser scan in RViz will often get out of alignment with surrounding map features, like a wall. At that point, the model of the robot in RViz might "teleport" a couple of grid cells in some direction. Then the laser scan points will match up with the map again, and the robot model will make another correction. I'm guessing this represents a kind of battle between what the odometry is telling gmapping versus the laser scan. If so, are there good parameters to set to minimize this?

Below are my various parameter files.

Thanks! patrick

My gmapping node:

  <node name="gmapping" pkg="gmapping" type="slam_gmapping" args="scan:=scan" ou
tput="screen">
    <param name="linearUpdate" value="0.1" />
    <param name="angularUpdate" value="0.05" /> 
    <param name="xmin" value="-20" />   
    <param name="ymin" value="-20" />
    <param name="xmax" value="20" />    
    <param name="ymax" value="20" />
    <param name="maxUrange" value="6" />        
  </node>

base_local_planner_params.yaml:

controller_frequency: 3.0
TrajectoryPlannerROS:
  max_vel_x: 0.2
  min_vel_x: 0.1
  max_rotational_vel: 1.0
  min_in_place_rotational_vel: 0.2
  acc_lim_th: 5.0
  acc_lim_x: 1.0
  acc_lim_y: 1.0
  holonomic_robot: false
  yaw_goal_tolerance: 0.25
  xy_goal_tolerance: 0.2

  goal_distance_bias: 0.8
  path_distance_bias: 0.8
  sim_time: 1.5
  heading_lookahead: 0.325
  oscillation_reset_dist: 0.05

  vx_samples: 10
  vtheta_samples: 40
  dwa: false

costmap_common_params.yaml

obstacle_range: 5.0
raytrace_range: 3.5
robot_radius: 0.17
inflation_radius: 0.65
observation_sources: scan
scan: {sensor_frame: /kinect_depth_frame, data_type: LaserScan, topic: /scan, ma
rking: true, clearing: true}

local_costmap_params.yaml

local_costmap:
   global_frame: /odom
   robot_base_frame: /base_link
   update_frequency: 3.0
   publish_frequency: 0.0
   static_map: false
   rolling_window: true
   width: 4.0
   height: 4.0
   resolution: 0.1
   transform_tolerance: 0.5

global_costmap_params.yaml

global_costmap:
   global_frame: /map
   robot_base_frame: /base_link
   update_frequency: 3.0
   publish_frequency: 0.0
   static_map: true
   transform_tolerance: 0.5