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1 – 10 of 21Zongyu Chen, Jiuzhi Dong and Xingfei Li
Microsyn signal generators have been used in high-precision inertial sensors for their good structural stiffness and high sensitivity. However, as the stator and the rotor of the…
Abstract
Purpose
Microsyn signal generators have been used in high-precision inertial sensors for their good structural stiffness and high sensitivity. However, as the stator and the rotor of the microsyn are both constructed of silicon-steel laminations with high permeability, an extremely small non-concentricity between the stator and rotor of microsyn will cause two random reaction torques acting on the output axis. As a result, difficulty arises in compensating for these random reaction torques. This study aims to investigate the electromagnetic fields of a novel angular transducer characterized by high sensitivity.
Design/methodology/approach
Based on the operation principles of the new transducer, the output voltage is decided by the time rate of change of the net magnetic flux of each output pole. The transient analysis of the electromagnetic field of the transducer is carried out by ANSYS Maxwell-3D.
Findings
The distributions of the magnetic flux of the transducer’s interior and eddy current on the rotor are consistent with the results of theory analysis. Moreover, the leakage flux mainly distributes nearby the excitation poles. The novel small-angle transducer also possesses a remarkably low reaction torque and power loss.
Practical implications
Study on the electromagnetic fields of the new transducer not only provides a powerful basis to further improve the precision of the new transducer but also expands the scope of applications of the new transducer.
Originality/value
This new transducer is not only characterized by a high sensitivity, high linearity and fast response but also extremely low reaction torque and power losses. Thus, the new transducer is suitable for high-precision inertial sensors.
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With the introduction of three new linear transducer assemblies and a new counter unit the Ferranti Measurement and Inspection Group, Dalkeith, Scotland, now offer, within the…
Abstract
With the introduction of three new linear transducer assemblies and a new counter unit the Ferranti Measurement and Inspection Group, Dalkeith, Scotland, now offer, within the Acculin range, six different digital read‐out (DRO) systems for machine‐tools.
Abstract
Purpose
The purpose of this paper is to study the preparation and characterisation of poly(p‐phenylene vinylene), PPV/TiO2 photoluminescent (PL) nanofibres, and the causes of the blue‐shift in PL spectrum of the as‐prepared composite nanofibres.
Design/methodology/approach
A simple method coupling sol‐gel method and electrospinning technology was used to prepare PPV/TiO2 nanofibres from precursory PPV solution.
Findings
Small‐angle X‐ray diffractometer showed that the nano‐TiO2 was mainly amorphous in composite nanofibres. The PL spectrum of the composite nanofibres confirmed the conclusion that there was a slight blue‐shift in the PL spectrum owing to the existence of TiO2 nanoparticles.
Research limitations/implications
The nanofibres collected aligned in random orientation, if parallel nanofibres were obtained. Practical applications will be effected.
Practical implications
The electrospinning method provides an effective strategy for preparing polymer composite nanomaterials.
Originality/value
Composite nanofibres will have potential applications for green optical/electric devices such as LEDs, sensors, transducers and flat panel displays.
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Rosario Borrelli, Umberto Mercurio and Simona Alguadich
The purpose of this paper is to improve knowledge of the water impact phenomenon from both the experimental and numerical points of view.
Abstract
Purpose
The purpose of this paper is to improve knowledge of the water impact phenomenon from both the experimental and numerical points of view.
Design/methodology/approach
A drop test campaign on water was carried out on semi‐cylindrical steel structures. Therefore, an experimental database for validation purpose was generated. Subsequently, a finite element model was developed in LS‐DYNA in order to reproduce the tests. The behaviour of water was modeled by using the smoothed particle hydrodynamics (SPH) methods. Numerical simulations were compared to experimental data and the influence of some numerical parameters on the simulations was investigated.
Findings
The FE model was found to be able to reproduce the tests, at least in terms of acceleration peak and distribution of plastic deformation. Acceptable prediction was also found for the pressure peak in soft areas.
Research limitations/implications
In case of low velocity impact, the water model was found to be too rigid and the acceleration peaks were over‐predicted by the simulations. Further investigations are needed to adjust the water model in order to obtain better results also in the case of low velocity impact.
Originality/value
The experimental database could be very useful to the crashworthiness community to validate their numerical models. Moreover, the present paper provides guidelines to modelling the water impact correctly.
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Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States…
Abstract
Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued.
Zhiqiang Huang, Lei He, ZhaoXin Gao, Yingqi Jia, Yewei Kang, Dou Xie and Chunli Fu
This paper aims to introduce a new acoustic positioning method to solve the problem of space positioning for online inspection robots within the storage tank.
Abstract
Purpose
This paper aims to introduce a new acoustic positioning method to solve the problem of space positioning for online inspection robots within the storage tank.
Design/methodology/approach
The proposed positioning system comprises two acoustic signal emitters and two receivers. Emitters are brought by the robot into the storage tank. Receivers are mounted on the external edge of the storage tank floor. The spatial coordinate values and motion directions of the robot in the storage tank are calculated by using the proposed acoustic positioning algorithm.
Findings
The experiment results and positioning error analysis indicate that the method can obtain the data of robotic space coordinates and motion orientation, while the positioning error of the method can be less than 20 cm. The accuracy reaches the positioning technology level of other tank online inspection robots.
Originality/value
This method not only expands the positioning of the inspection robots from 2D plane to 3D space but also significantly reduces the number of positioning sensors carried by a robot and improves the safety of a robot in the tank.
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Optical fibre multiplexed sensors are used to make measurements at multiple, discrete locations, usually by sending optical signals between each measurement location and a…
Abstract
Optical fibre multiplexed sensors are used to make measurements at multiple, discrete locations, usually by sending optical signals between each measurement location and a conveniently positioned optical interrogation instrument. It is rapidly becoming practical to construct multiplexed optical fibre sensor arrays based on in‐fibre Bragg gratings. A Bragg grating can be produced in an optical fibre by writing a periodic variation in the refractive index of the fibre’s core along the axis, using ultra‐violet light. Multiplexing applications will appear ranging from the small scale, with only a few sensors, up to very large scales with hundreds of sensors.
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THE thirty‐eighth annual Exhibition of the Physical Society was held at the Imperial College, South Kensington, on April 8–13, and the account which follows describes a few of the…
Abstract
THE thirty‐eighth annual Exhibition of the Physical Society was held at the Imperial College, South Kensington, on April 8–13, and the account which follows describes a few of the items shown, which have been selected because of their more direct interest for the aeronautical engineering profession.
Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States…
Abstract
Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued
Ling Chen, Sen Wang, Klaus McDonald‐Maier and Huosheng Hu
The main purpose of this paper is to investigate two key elements of localization and mapping of Autonomous Underwater Vehicle (AUV), i.e. to overview various sensors and…
Abstract
Purpose
The main purpose of this paper is to investigate two key elements of localization and mapping of Autonomous Underwater Vehicle (AUV), i.e. to overview various sensors and algorithms used for underwater localization and mapping, and to make suggestions for future research.
Design/methodology/approach
The authors first review various sensors and algorithms used for AUVs in the terms of basic working principle, characters, their advantages and disadvantages. The statistical analysis is carried out by studying 35 AUV platforms according to the application circumstances of sensors and algorithms.
Findings
As real‐world applications have different requirements and specifications, it is necessary to select the most appropriate one by balancing various factors such as accuracy, cost, size, etc. Although highly accurate localization and mapping in an underwater environment is very difficult, more and more accurate and robust navigation solutions will be achieved with the development of both sensors and algorithms.
Research limitations/implications
This paper provides an overview of the state of art underwater localisation and mapping algorithms and systems. No experiments are conducted for verification.
Practical implications
The paper will give readers a clear guideline to find suitable underwater localisation and mapping algorithms and systems for their practical applications in hand.
Social implications
There is a wide range of audiences who will benefit from reading this comprehensive survey of autonomous localisation and mapping of UAVs.
Originality/value
The paper will provide useful information and suggestions to research students, engineers and scientists who work in the field of autonomous underwater vehicles.
Details