Iwan Ulrich

VFH+: reliable obstacle avoidance for fast mobile robots

This paper presents further improvements on the earlier vector field histogram (VFH) method developed by Borenstein-Koren (1991) for real-time mobile robot obstacle avoidance. The enhanced method, called VFH+, offers several improvements that result in smoother robot trajectories and greater reliability. VFH+ reduces some of the parameter tuning of the original VFH method by explicitly compensating for the robot width. Also added in VFH+ is a better approximation of the mobile robot trajectory, which results in higher reliability.

Appearance-based place recognition for topological localization

This paper presents a new appearance-based place recognition system for topological localization. The method uses a panoramic vision system to sense the environment. Color images are classified in real-time based on nearest-neighbor learning, image histogram matching, and a simple voting scheme. The system has been evaluated with eight cross-sequence tests in four unmodified environments, three indoors and one outdoors. In all eight cases, the system successfully tracked the mobile robots position. The system correctly classified between 87% and 98% of the input color images. For the remaining images, the system was either momentarily confused or uncertain, but never classified an image incorrectly.

VFH/sup */: local obstacle avoidance with look-ahead verification

This paper presents an enhancement to the earlier developed vector field histogram (VFH) method for mobile robot obstacle avoidance. The enhanced method, called VFH/sup */ successfully deals with situations that are problematic for purely local obstacle avoidance algorithms. The VFH/sup */ method verifies that a particular candidate direction guides the robot around an obstacle. The verification is performed by using the A/sup */ search algorithm and appropriate cost and heuristic functions.

The GuideCane-applying mobile robot technologies to assist the visually impaired

The GuideCane is a device designed to help blind or visually impaired users navigate safely and quickly among obstacles and other hazards. During operation, the user pushes the lightweight GuideCane forward. When the GuideCanes ultrasonic sensors detect an obstacle, the embedded computer determines a suitable direction of motion that steers the GuideCane and the user around it. The steering action results in a very noticeable force felt in the handle, which easily guides the user without any conscious effort on his/her part.

Mobile Robotics Technology in the Service of the Blind and Visually Impaired

Abstract This paper describes two computerized travel aids for the blind and visually impaired that use technologies originally developed for mobile robots. The first device - the Nav Belt is like a belt and, via a set of stereo earphones, provides acoustic signals that guide the user around obstacles. The second device - the Guide Cane uses the same mobile robotics technology as the Nav Belt but it is a wheeled device pushed ahead of the user via an attached cane. When it detects an obstacle it steers around it. The user immediately feels this steering action and follows the Guide Canes new path.