Obstacle Avoidance Experiments Research Articles

Autonomous Mobile Robot Locomotion by Multifunctional Use of Wide Angle Fovea Sensor

The wide-angle fovea (WAF) sensor comprises a specially made wide-angle fovea lens and a commercially available CCD/CMOS camera with photosensitive elements of uniform size. The sensor realizes a 120-degree-wide field of view (FOV) and high magnification in the central FOV without increasing the number of pixels per image. This paper focuses on the multifunctional use of an input image with space-variant spatial resolution that enables an autonomous mobile robot to avoid obstacles during locomotion. In order to use the WAF-input image efficiently, image processing for central vision, i.e., detection of 3D obstacles, and image processing for peripheral vision, i.e., self-localization of the mobile robot, are performed simultaneously and cooperatively. The comparison of the simulation results of spatial resolutions of the WAF lens and a pinhole camera (PHC) lens shows that the WAF lens can be used for depth measurement in the central FOV and self-localization in the peripheral FOV by the parallel stereo method and the two-parallel-line algorithm, respectively. The results obtained by the WAF lens are more accurate than those obtained by the PHC lens. Autonomous locomotion of the mobile robot has been demonstrated by performing two obstacle avoidance experiments.

Echolocation signal structure in the Megachiropteran bat Rousettus aegyptiacus Geoffroy 1810

Rousettus aegyptiacus Geoffroy 1810 is a member of the only genus of Megachiropteran bats to use vocal echolocation, but the structure of its brief, click-like signal is poorly described. Although thought to have a simple echolocation system compared to that of Microchiroptera, R. aegyptiacus is capable of good obstacle avoidance using its impulse sonar. The energy content of the signal was at least an order of magnitude smaller than in Microchiropteran bats and dolphins (approximately 4 x 10(-8) J m(-2)). Measurement of the duration, amplitude and peak frequency demonstrate that the signals of this animal are broadly similar in structure and duration to those of dolphins. Gabor functions were used to model signals and to estimate signal parameters, and the quality of the Gabor function fit to the early part of the signal demonstrates that the echolocation signals of R. aegyptiacus match the minimum spectral spread for their duration and amplitude and are thus well matched to its best hearing sensitivity. However, the low energy content of the signals and short duration should make returning echoes difficult to detect. The performance of R. aegyptiacus in obstacle avoidance experiments using echolocation therefore remains something of a conundrum.

探査ローバの障害物回避実験による考察(惑星探索ローバ)

探査ローバの障害物回避実験による考察(惑星探索ローバ)

Kinematics and the implementation of an elephant's trunk manipulator and other continuum style robots.

Traditionally, robot manipulators have been a simple arrangement of a small number of serially connected links and actuated joints. Though these manipulators prove to be very effective for many tasks, they are not without their limitations, due mainly to their lack of maneuverability or total degrees of freedom. Continuum style (i.e., continuous "back-bone") robots, on the other hand, exhibit a wide range of maneuverability, and can have a large number of degrees of freedom. The motion of continuum style robots is generated through the bending of the robot over a given section; unlike traditional robots where the motion occurs in discrete locations, i.e., joints. The motion of continuum manipulators is often compared to that of biological manipulators such as trunks and tentacles. These continuum style robots can achieve motions that could only be obtainable by a conventionally designed robot with many more degrees of freedom. In this paper we present a detailed formulation and explanation of a novel kinematic model for continuum style robots. The design, construction, and implementation of our continuum style robot called the elephant trunk manipulator is presented. Experimental results are then provided to verify the legitimacy of our model when applied to our physical manipulator. We also provide a set of obstacle avoidance experiments that help to exhibit the practical implementation of both our manipulator and our kinematic model.

Multi-Functional Application of Wide-Angle Foveated Vision Sensor in Mobile Robot Navigation

This paper presents a concrete multi-functional application of Wide-Angle Foveated Vision Sensor (WAFVS) in which a special optical lens, designed by mimicking the human eye, plays a major role. The author has conducted experiments of obstacle avoidance in mobile robot navigation. 3D information of obstacles and locational information of mobile robot, which are characterized by the lens property, are acquired from central vision with high accuracy and peripheral vision with fewer pixels, respectively. Cooperation between them is executed by flexible parallel processing to improve navigation quality.