oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
A New Type of Magnetic Actuator Capable of Wall-Climbing Movement Using Inertia Force  [PDF]
H. Yaguchi,S. Sakuma,T. Kato
Journal of Engineering , 2014, DOI: 10.1155/2014/903178
Abstract: This paper proposes a new type of a magnetic actuator that operates on a resonance energy of a mass-spring model by using an electromagnetic force. The magnetic actuator is moved by the difference in an inertia force during one period of vibration. Experimental result demonstrates that a horizontal speed of the magnetic actuator was 7.4?mm/s with load mass of 50?g. We considered a method of a cable-free movement of the actuator by using two iron rails and four permanent magnets. The magnetic actuator is able to move stably a ceiling plane and a wall plane. This actuator is able to move on the plane of the magnetic materials only a function generator and a power amplifier. 1. Introduction Under the field and the environmental situation that a human being cannot inspect directly, a robot capable of actual work and inspection is desired at the field of each industry. In a large tank and bridge, periodical inspection is required. In the building, the inspection of the outer wall and the actual work of the wall surface are required. As an adsorption method for wall surface movement, a method using magnetic attractive force [1–3] and the method to produce negative pressure [4] by using the devices such as a sucker or the pump, the method using van der Waals forces [5], a technique using the adhesive elastomer [6], and the method of magnetic wheel [7] were suggested, and the establishment for principle of locomotion has been accomplished. However, at the mobile robot as mentioned above, the moving speed is low by problem of controllability and own weight. The development of a superior actuator of lightweight and operability is very important. We demonstrated a cable-free microactuator [8, 9] of vibration type by using an inertia force. In this previous paper, examination of cable-free and downsizing of the actuator were mainly considered. The moving properties of the actuator are not examined. In this paper, we again propose a new type of a magnetic actuator capable of movement on a magnetic substance such as an iron rail using an inertial force of a mass-spring model. A prototype actuator was fabricated, and it is able to move on the magnetic substance. Experimental result shows that a horizontal speed of the actuator was 7.4?mm/s with load mass of 50?g. In addition, we considered a method of a cable-free movement for the actuator by four permanent magnets and using two iron rails. It was confirmed that this actuator is able to move on the plane of the magnetic materials only a function generator and a power amplifier. 2. Structure of the Magnetic Actuator by
Experimental performance evaluation of magnetic actuator used in rotating machinery analysis
Castro, Hélio F. de;Furtado, Rogério M.;Cavalca, Katia L.;Pederiva, Robson;Butzek, Norman;Nordmann, Rainer;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2007, DOI: 10.1590/S1678-58782007000100013
Abstract: a magnetic actuator as excitation source in rotative systems is proposed, in order to accomplish modal analysis without contact between the actuator and the rotor. although the use of electromagnets for applying forces to rotating machinery have been carried out with high performance level (for example, magnetic bearings), the development of a conveniently easy and cheap device for laboratory application presents interesting contribution to experimental methods used in test rigs based on similarity design to rotating machinery. the initial concept of the magnetic actuator proposed here is simple, but enables either the external excitation without contact or the vibration control when associated with a controller system. however, the calibrations of performance characteristics to attend the dynamic demand of the system in not so trivial. following this focus, the paper brings practical experience and discussion about the development, calibration and performance analysis of a magnetic actuator used for rotating machinery tests. the influence of the electrical current in the actuator coils, the air-gap between actuator and rotative system, the type of surface of the actuator poles (flat or curved) as well as excitation frequency was experimentally verified and compared with theoretical concepts. force estimation was carried out and compared with the measured force. the estimation was based on the magnetic flux density, measured by hall sensors, or input current and initial air-gap.
Performance of Cableless Magnetic In-Piping Actuator Capable of High-Speed Movement by Means of Inertial Force  [PDF]
Hiroyuki Yaguchi,Tomohiro Izumikawa
Advances in Mechanical Engineering , 2011, DOI: 10.1155/2011/485138
Abstract: The present paper proposes a novel cableless magnetic actuator with a new propulsion module that exhibits a very high thrusting force. This actuator contains an electrical inverter that directly transforms DC from button batteries into AC. The electrical DC-AC inverter incorporates a mass-spring system, a reed switch, and a curved permanent magnet that switches under an electromagnetic force. The actuator is moved by the inertial force of the mass-spring system due to mechanical resonance energy. The experimental results show that the actuator is able to move upward at a speed of 19.7?mm/s when using 10 button batteries when pulling a 20?g load mass. This cableless magnetic actuator has several possible applications, including narrow pipe inspection and maintenance. 1. Introduction There is increasing demand for in-piping robots able to quickly find damage and remedy undesirable conditions inside pipes used in plants for chemical and biological materials, nuclear power, and other such installations. Safety issues have encouraged the growing use of such robots in recent years for a variety of duties, including not only inspections, but also maintenance and cleaning. A number of studies have investigated the mechanisms of an actuator having an attached electric cable to provide locomotion in the pipe using devices such as piezoelectric elements [1, 2], shape memory alloys [3, 4], and electromagnetic motors [5–9]. However, little research has been conducted on cableless robots [10–12]. In general, the design of cable type robots is quite simple compared to the design of cableless robots. There are several potential problems in the design, however, with regard to extending the range and avoiding tangling of the cable, and thus it is clearly desirable to adopt a cableless system. Although long-range movement is necessary for the inspection of thin pipes in plants, no cableless mover capable of movement over one hundred meter in a thin pipe of several millimeters has been developed. The present authors previously proposed [12] a novel cableless magnetic actuator that provides propulsion by means of the inertial force of a mass-spring system excited by an electromagnetic force. Since a large-amplitude vibration can be easily provided by a small excitation force, this type of the actuator has high propulsion. This paper proposes a new type of the cableless magnetic actuator which exhibits a very high thrusting force and is capable of extension to propulsion of the robot within a thin pipe. In order to improve the moving characteristics of the actuator, an
Modeling and performance evaluation of an electromechanical valve actuator for a camless IC engine  [PDF]
Eid Mohamed
International Journal of Energy and Environment , 2012,
Abstract: Valve train control is one of the best strategies for optimizing efficiency and emissions of Internal Combustion (IC) engines. Applications of solenoid valve actuators in (IC) engines can facilitate operations such as variable valve timing and variable valve lifting for improved the engine performance, fuel economy and reduce emission, the electromechanical valve actuator (EMVA) uses solenoid to actuate valve movement independently for the application of (IC) engine. In this work presents the effects of design and operating parameters on the system dynamic performances of the actuator and the proposed an (EMVA) structure by incorporating the hybrid magneto-motive force (MMF) implementation in which the magnetic flux is combined by the coil excitation and permanent magnets. A two-degree-of-freedom lumped parameter model is used to simulate the response of valve actuator system in the opening and closing. The model and control of an electromagnetic valve (EMV) are described. This is done using electromagnetic force to open and close the valve and a controller regulates the motion specifications required. The developments controller is based on a state-space description of the actuator that is derived based on physical principles and parameter identification. Linear-quadratic regulator design (LQR) optimal control is designed with the evaluation reasonable the performance and energy of (EMV) valve are obtained with the design.
THE APPLICATION OF MAGNETIC FORCE MICROSCOPY IN THE FIELD OF MAGNETIC MATERIALS
磁力显微镜在磁性材料领域的应用

TIAN Fang,WANG Naixin,BAI Chunli,
田芳
,王乃新,白春礼

材料研究学报 , 1996,
Abstract: Magnetic force microscopy (MFM) is an important powerful technitque in the field of researchin magnetic materials. An introduction to the principle, application and perspectives for this technique ispresented. The foreseeable advantages of MFM in the study of organic ferromagnets and biomolecules are also discussed.
In-piping Magnetic Actuator Capable of Inspection in a Thin Complex Pipe  [cached]
Hiroyuki Yaguchi,Kazushige Kamata
Mechanical Engineering Research , 2012, DOI: 10.5539/mer.v2n2p1
Abstract: This paper proposes a magnetic actuator of a new type that exhibits a very high thrusting force and is capable of a reversible motion in a complex pipe. The magnetic actuator of the reversible type due to opening and closing of a compound material by using elongation and contraction of four shape-memory-alloy (SMA) coils was fabricated. The magnetic actuator using the difference in the frictional force between the forward and backward motion of the compound material propels in only one direction. Experimental result shows that the prototype actuator was able to climb at 38.7 mm/s in the straight pipe when pulling the load mass of 50 g. In addition, the measurement of an average speed carried out for two patterns of movement in a complex pipe with many curved parts and step parts. The prototype actuator was able to move in the complex pipe over the average speed of 35 mm/s. This actuator has many possible applications, including small pipe inspection.
MAGNETIC ANISOTRIPY IN SPUTTERED NdFeB FILMS
Gu Benxi Zhai Hongru Nanjing University,Nanjing,ChinaHHomburg SMethfessel Ruhr-University Bochum,Germany,
Gu Benxi Zhai Hongru Nanjing University
,Nanjing,ChinaH.Homburg S.Methfessel Ruhr-University Bochum,Germany

金属学报(英文版) , 1992,
Abstract: The amorphous and crystalline NdFeB films were prepared by RF sputtering at differentsubstrate temperatures.The crystalline specimens,prepared at 600℃ have strong perpendicu-lar anisotropy and high coercivity.And the cystallized alloy from amorphous state also hasstrong perpendicular anisotripy.
Monopolelike probes for quantitative magnetic force microscopy: calibration and application  [PDF]
S. Vock,F. Wolny,T. Mühl,R. Kaltofen,L. Schultz,B. Büchner,C. Hassel,L. Lindner,V. Neu
Physics , 2011, DOI: 10.1063/1.3528340
Abstract: A local magnetization measurement was performed with a Magnetic Force Microscope (MFM) to determine magnetization in domains of an exchange coupled [Co/Pt]/Co/Ru multilayer with predominant perpendicular anisotropy. The quantitative MFM measurements were conducted with an iron filled carbon nanotube tip, which is shown to behave like a monopole. As a result we determined an additional in-plane magnetization component of the multilayer, which is explained by estimating the effective permeability of the sample within the \mu*-method.
Magnetic Behavior of Sintered NdFeB Magnets on a Long-Term Timescale  [PDF]
Minna Haavisto,Sampo Tuominen,Timo Santa-Nokki,Harri Kankaanp??,Martti Paju,Pekka Ruuskanen
Advances in Materials Science and Engineering , 2014, DOI: 10.1155/2014/760584
Abstract: Stable polarization of permanent magnets over the lifetime of the application is an important aspect in electrical machine design. Specification of the long-term stability of magnet material is difficult, since knowledge of the phenomenon is incomplete. To be able to optimize magnet material selection, the long-term magnetic behavior of the material must also be understood. This study shows that material with a very square JH curve is stable until a certain critical operating temperature is reached. Major losses are detected as the critical temperature is exceeded. Material with a rounder JH curve does not show a well-defined critical temperature, but increasing losses over a large temperature range. The critical temperature of a material is also dependent on the field conditions. Results differ whether the tests are performed in an open or closed magnetic circuit. In open-circuit tests, the opposing field is not homogeneously distributed throughout the volume of the magnet and thus the long-term behavior is different than that in closed-circuit conditions. Open-circuit tests seem to give bigger losses than closed-circuit tests in cases where the permeance coefficient of the open-circuit sample is considered to be the average permeance coefficient, calculated according to the dimensions of the magnet. 1. Introduction During the last decade, the utilization of sintered NdFeB magnets in large motor and generator applications has become more common. The remanence of NdFeB material is superior in comparison to other types of magnet materials. The challenge is coercivity, which decreases rapidly as the temperature rises. Coercivity at elevated temperatures can be increased by partial substitution of Nd with Dy. Increasing Dy content, however, decreases the remanence and is therefore an unfavorable way of improving stability at elevated temperatures. In addition, dysprosium is not as abundant as neodymium in ores and thus it is much more expensive than Nd. A lot of effort has recently been put into development work for lower Dy content magnets with higher coercivities [1–3]. One way to avoid excess Dy additions in magnets is the optimization of the application by means of appropriate material selection. This requires, however, precise knowledge of the magnetic behavior of the materials concerned. FE-modeling is an efficient way of designing the application. The optimization of the magnetic circuit is thus much easier today than a few decades ago. Irreversible polarization losses occurring in magnets during the operation of machines are difficult to estimate,
SMA Actuator Technology Application in Stewart Platform Construction  [PDF]
Abdul Malik Bin Surdi Roslan,Victor Amirtham,T. Nagarajan,Fakhruldin Mohd Hashim
Journal of Applied Sciences , 2011,
Abstract: This research is a study of using a Shape Memory Alloy (SMA) as an actuator in a robotic application for a 6 Degrees of Freedom (DOF) Stewart Platform. Conventional actuators such as hydraulics, pneumatics and mechanical will be replaced by a new breed of technological advancement of SMA wires. The focused area of study is on a mini sized Stewart Platform which eliminates bulky conventional actuators. Hence, SMA will have the distinctive advantages over the other types of actuators. The mini Stewart Platform consists of a fixed base and a platform connected with specially designed SMA actuators along with a counter force spring. The support post for the platform uses a counter force spring material viz. sponges. Further study includes the design of a Pulse Width Modulation (PWM) technique power supply circuit for the controlling the current to increase the temperature of the heat sensitive wires. For the SMA wires, the cooling system serves as an important role to ensure the wires return back to its original length without any damage after they had been stretched out. Kinematic studies have been carried out to achieve required displacements of the platform.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.