Vector Field Histogram - VFH+

VFH+

The VFH algorithm was improved in 1998 and renamed the VFH+. Improvements include:

1. Threshold hysteresis: a hysteresis increases the smoothness of the planned trajectory.
2. Robot body size: robots of different sizes are taken into account, eliminating the need to manually adjust parameters via low-pass filters.
3. Obstacle look-ahead: sectors that are blocked by obstacles are masked in VFH+, so that the steer angle is not directed into an obstacle.
4. Cost function: a cost function was added to better characterize the performance of the algorithm, and also gives the possibility of switching between behaviors by changing the cost function or its parameters.