﻿

# Simple Vector Field Histogram VI

LabVIEW 2013 Robotics Module Help

Edition Date: June 2013

Part Number: 372983D-01

»View Product Info

Owning Palette: Obstacle Avoidance VIs

Requires: Robotics Module

Identifies obstacles and gaps, or open areas, in the robot environment, which you can use to implement reactionary motion in a robot vehicle.

Use the Advanced VFH VI rather than this VI for goal-directed obstacle avoidance.

 Note  You can use any unit of measurement to specify distance and angle values. However, always use consistent units when you specify these values.

Example

panic range defines the range at which this VI identifies an obstacle as an area of the environment to avoid.
 panic threshold distance specifies the maximum distance at which obstacle within panic range is TRUE. panic threshold angle specifies the maximum angle at which obstacle within panic range is TRUE.
distances specifies the distances between the robot sensor and objects in the robot environment.
direction angles specifies the angles at which objects are located with respect to the center of the sensor. Positive values represent locations to the right of the center of the sensor, and negative values represent positions to the left of the center of the sensor. Elements in direction angles correspond to elements in distances.
distance threshold specifies the distance at which this VI does not consider objects to be obstacles. This VI ignores any objects at distances greater than distance threshold.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
obstacle within panic range is TRUE if an object within panic threshold angle is nearer to the sensor than the panic threshold distance.
largest gap describes the largest open area in the robot environment.
 angle to gap contains the direction of the open area with respect to the robot sensor. size of gap contains the angular size, or visual diameter, of the open area, measured as an angle.
nearest obstacle describes the object nearest to the sensor.
 angle to obstacle contains the direction of the obstacle with respect to the sensor. distance to obstacle contains the distance between the sensor and the obstacle.
histogram returns the histogram data that represents the distances to objects in range of the sensor, arranged by angle and direction.
error out contains error information. This output provides standard error out functionality.

## Example

Refer to the LIDAR Guided Robot.lvproj in the labview\examples\robotics\LIDAR Guided Robot directory for an example of using the Simple Vector Field Histogram VI.