Many types of omnidirectional wheels with passive rollers have gaps between rollers. Since these gaps cause a wheel to make discontinuous contact with the ground, they lead to vertical and/or horizontal vibrations during wheel operation. In addition, the radii of passive rollers are related to the height of a bump an omnidirectional wheel can surmount. In this research a new design of the alter...

* Corresponding author. Tel.: +1-612-625-2374; fax: +1-612-626-7750. E-mail addresses: [email protected] (A. Drescher), [email protected] (J.P.Hambleton). 1 On modeling a rolling wheel in the presence of plastic deformation as a threeor two-dimensional process J.P. Hambleton and A. Drescher Department of Civil Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, MN 55455, US...

Accurate disturbance models are necessary to predict the e!ects of vibrations on the performance of precision space-based telescopes, such as the Space Interferometry Mission (SIM). There are many possible disturbance sources on such spacecraft, but mechanical jitter from the reaction wheel assembly (RWA) is anticipated to be the largest. A method has been developed and implemented in the form ...

in this paper effects of fractured sleepers on rail track vibration under moving wheelset have been investigated. two parallel rails of the track have been modeled as euler-bernoulli beams on elastic points as rail pads. also sleepers have been modeled as visco-elastic euler-bernoulli beams. it is assumed that, some sleepers under the rail track have been fractured and modeled by two beams. the...

The behavioral consequences of uncontrollable stress, or learned helplessness (LH) behaviors, are thought to involve hyperactivity of serotonergic (5-HT) neurons in the dorsal raphe nucleus (DRN). Other brain regions implicated in LH and capable of affecting 5-HT systems, such as the bed nucleus of the stria terminalis (BNST), amygdala, and habenula, could contribute to DRN 5-HT hyperactivity d...

We evaluated the effect of voluntary exercise on spontaneous physical activity (SPA) and food consumption in mice from 4 replicate lines bred for 57 generations for high voluntary wheel running (HR) and from 4 non-selected control (C) lines. Beginning at ~24 days of age, mice were housed in standard cages or in cages with attached wheels. Wheel activity and SPA were monitored in 1-min intervals...

A bogie frame is the most important railway vehicle’s component that supports almost weight of system, and it subjected to various excitations loads can result in failure structure. The dynamic forces influenced by excitations, both internal external, speed up system's fatigue failure. This paper aims analyse impact wheel flats on life a high-speed frame. To accomplish this study, Chinese (CRH2...

Introduction It is generally believed that exercise produces its effects by activating central opioid receptors; there are little data that support this claim. The periaqueductal gray (PAG) and rostral ventromedial medulla (RVM) are key nuclei in opioid-induced analgesia, and opioids interact with serotonin to produce analgesia. Objectives The purpose was to examine central inhibitory mechani...

This paper presents analytical models to investigate the steering maneuvers of planetary exploration rovers on loose soil. The models are based on wheel-soil interaction mechanics, or terramechanics, with which the traction and disturbance forces of a wheel are evaluated for various slip conditions. These traction forces are decomposed into the longitudinal and lateral directions of the wheel. ...

We formulate the kinematic equations-of-motion of wheeled mobile robots incorporating conuentionaI, omnidirectional, and ball wheels. While our approach parallels the kinematic modeling of stationary manipulators, we extend the methodology to accommodate such special characteristics of wheeled mobile robots as multiple closed-link chains, higher-pair contact points between a wheel and a surface...