Strange movement with hector_navigation

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Hello there!

Me and my team are trying to get a mobile robot running for autonomous exploration. Since the only sensor we have available is a Lidar sensor (RPLIDAR A2), we went with Hector SLAM(http://wiki.ros.org/hector_slam), because it requires no additional sensors.

Mapping works great, all obstacles are being mapped accordingly, the robot pose is also okay. However, when we try to do navigation, we get some strange results. We are using the Hector Navigationpackage (http://wiki.ros.org/hector_navigation) - more specifically, the hector_exploration_node and the simple_exploration_controller. The path gets computed fine, and velocity commands get published (which we then process through our own Motor Controller node).

However, the robot keeps moving back and forth all the time - it eventually reaches the goal, but it is constantly moving back and forth. Our costmap (edited the one that comes with the package) is as follows:

    global_costmap:

  map_type: costmap
  track_unknown_space: true
  unknown_cost_value: 255
  obstacle_range: 2.5
  raytrace_range: 3.0
  footprint: [[0.18, 0.15], 
              [-0.18, 0.15],
              [-0.18, -0.15],
              [0.18, -0.15]]
  inflation_radius: 0.32
  #transform_tolerance: 0.5 
  inscribed_radius: 0.15 
  circumscribed_radius: 0.24 

  global_frame: /map
  robot_base_frame: /base_link
  update_frequency: 0.5 
  publish_frequency: 0.1 
  static_map: true
  rolling_window: false

  #Investigate what this actually does
  cost_scaling_factor: 10.0

We modified the parameters of the costmap that came with hector_navigation to fit our mobile base (modified: footprint, inscribed_radius, and curcumscribed_radius). We looked at the code in hector_navigation and really have no idea what the cause for this behavior is.

The rest of the hardware used is:

• Lynxmotion Aluminum A4WD1 Rover Kit

• Sabertooth Dual 12A 6V-24V R/C Regenerative Motor Driver

  Did anyone else have this problem? How do we get the robot to simply move along the path, instead of going back and forth before eventually reaching the goal? Could it be that it is due to limited hardware?

  Additional information that could be useful:

• We are using ROS Kinetic on an NVidia Jetson TX2 board
• Turning works perfectly - as soon as a new path is computed, the robot turns into the desired direction. It is only linear movement that causes the back-and-forth motion.

We can provide any additional info if needed.