Design and analysis of a 2-DoF split-stator induction motor

A two degrees of freedom (2-DOF) actuator capable of producing linear translation, rotary motion, or helical motion would be a desirable asset to the fields of machine tools, robotics, and various apparatuses. In this paper, a novel 2-DOF split-stator induction motor was proposed and electromagnetic structure pa- rameters of the motor were designed and optimized. The feature of the direct-drive 2-DOF induction motor lies in its solid mover ar- rangement. In order to study the complex distribution of the eddy current field on the ferromagnetic cylinder mover and the motor’s operating characteristics, the mathematical model of the proposed motor was established, and characteristics of the motor were ana- lyzed by adopting the permeation depth method (PDM) and finite element method (FEM). The analytical and numerical results from motor simulation clearly show a correlation between the PDM and FEM models. This may be considered as a fair justification for the proposed machine and design tools.

Verification of the indoor gps system by comparison with points calibrated using a network of laser tracker measurements

This paper details a method of determining the uncertainty of dimensional measurement for a three dimensional coordinate measurement machine. An experimental procedure was developed to compare three dimensional coordinate measurements with calibrated reference points. The reference standard used to calibrate these reference points was a fringe counting interferometer with the multilateration technique employed to establish three dimensional coordinates. This is an extension of the established technique of comparing measured lengths with calibrated lengths. Specifically a distributed coordinate measurement device was tested which consisted of a network of Rotary-Laser Automatic Theodolites (R-LATs), this system is known commercially as indoor GPS (iGPS). The method was found to be practical and able to establish that the expanded uncertainty of the basic iGPS system was approximately 1 mm at a 95% confidence level. © Springer-Verlag Berlin Heidelberg 2010.

Dizziness in 10 year old children:an epidemiological study

OBJECTIVE: Current data about the prevalence and characteristics of dizziness in the paediatric population is very limited and the generalisability of extant studies to the UK population has not been explored. Our study aims to provide a robust estimate of the prevalence of dizziness in 10 year old children in the UK, to describe the characteristics of this dizziness and to explore whether this dizziness is socially patterned. METHODS: Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) was analysed (N=13,988). A total of 6965 of these children attended for a balance assessment session at age 10. Those who reported rotary vertigo were interviewed about their symptoms. Logistic regression was used to explore whether dizziness at age 10 is socially patterned. RESULTS: A total of 400 children reported rotary vertigo, giving a prevalence estimate of 5.7% [CI 5.2, 6.3%]. 13.1-20.6% of children reported experiencing their dizziness between 1 and 4 times a week (depending on the symptom). 51.5% of children had to stop what they were doing because of the dizziness making them feel unwell. A total of 60% of children reported headache as an accompanying symptom, tentatively suggesting a diagnosis of migraine, although there was no association between reports of headache and a maternal family history of migraine. 20.3% of children with dizziness also reported tinnitus and 17.3% reported that their hearing changed when they were dizzy. CONCLUSIONS: Dizziness in 10 year old children is not uncommon and in about half limits current activities. Rotary vertigo is commonly accompanied by dizziness of another description and also by headache. There is no evidence that dizziness at this age is socially patterned.