Supported configuration requests:
|position_index||integer||0||Index of the underlying position device.|
|laser_index||integer||0||Index of the laser device.|
|cell_size||length||0.1||Local occupancy map grid size (m).|
|window_diameter||integer||61||Dimensions of occupancy map (map consists of window_diameter X window_diameter cells).|
|sector_angle||integer||5||Histogram angular resolution, in degrees.|
|robot_radius||length||0.25||The radius of the robot (m).|
|safety_dist||length||0.1||The minimum distance the robot is allowed to get to obstacles (m).|
|max_speed||integer||200||The maximum allowable speed of the robot, in millimeters/second, the robot.|
|max_turnrate||integer||40||The maximum allowable turnrate of the robot.|
|free_space_cutoff||float||2000000.0||Unitless value. The higher the value, the closer the robot will get to obstacles before avoiding.|
|weight_desired_dir||float||5.0||Bias for the robot to turn to move toward goal position.|
|weight_current_dir||float||3.0||Bias for the robot to continue moving in current direction of travel.|
|distance_epsilon||length||0.5||Planar distance from the target position that will be considered acceptable.|
|angle_epsilon||angle||10 degrees||Angular difference from target angle that will considered acceptable.|
The primary parameters to tweak to get reliable performance are safety_dist and free_space_cutoff. In general, safety_dist determines how close the robot will come to an obstacle while turning (around a corner for instance) and free_space_cutoff determines how close a robot will get to an obstacle in the direction of motion before turning to avoid. From experience, it is recommeded that max_turnrate should be at least 15% of max_speed.
To get initiated to VFH, I recommend setting robot_radius to the radius of your robot and starting with the default values for other parameters and experimentally adjusting safety_dist and free_space_cutoff to get a feeling for how the parameters affect performance. Once comfortable, increase max_speed and max_turnrate. Unless you are familiar with the VFH algorithm, I don't recommend deviating from the default values for cell_size, window_diameter, or sector_angle.
For more information on the VFH driver, ask Chris Jones: firstname.lastname@example.org.