Research on variable frequency-loading curve in precision cropping system with high-speed and centrifugal action

Aimed at achieving a high speed and precision circumferential positioning of pipe under low energy consumption, a paralleling hydraulic control of variable frequency motor and valve (PHC-VFMV) system is designed for the swing mechanism of segment erector. Firstly, with a view to the working principle of the swing mechanism, a hydraulic circuit of the PHC-VFMV is designed. Then, two sub-circuits of the hydraulic circuit are separately modeled and equipped with suitable controllers. Finally, one valve control (VC) system and the designed PHC-VFMV system are tested in AMEsim platform. Results show that, while guaranteeing a good performance of speed and accuracy, the PHC-VFMV could achieve a better performance in energy saving than VC.

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Investigation of a new-type precision cropping system with variable-frequency vibration

International Journal of Mechanical Sciences ◽

10.1016/j.ijmecsci.2006.08.010 ◽

2006 ◽

Vol 48 (12) ◽

pp. 1333-1340 ◽

Cited By ~ 12

Author(s):

C.J. Hua ◽

S.D. Zhao ◽

L.J. Zhang ◽

W. Liu

Keyword(s):

Cropping System ◽

Variable Frequency ◽

New Type

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Investigation on the bar clamping position of a new type of precision cropping system with variable frequency vibration

International Journal of Machine Tools and Manufacture ◽

10.1016/j.ijmachtools.2006.09.003 ◽

2007 ◽

Vol 47 (7-8) ◽

pp. 1125-1131 ◽

Cited By ~ 7

Author(s):

L.J. Zhang ◽

S.D. Zhao ◽

J. Lei ◽

W. Liu

Keyword(s):

Cropping System ◽

Variable Frequency ◽

New Type

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High-Precision Locating Technology of Automatic Port High-Speed & Heavy Load Rail Power-Driven Trolley

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.442.276 ◽

2012 ◽

Vol 442 ◽

pp. 276-280

Author(s):

Xi Xia Huang ◽

Xiang Pin Kong

Keyword(s):

Control System ◽

High Precision ◽

High Speed ◽

Speed Control ◽

Variable Frequency ◽

Heavy Load ◽

Precise Positioning ◽

Soft Start ◽

Speed Control System ◽

Braking Process

This paper proposes high-precision locating technology for high-speed & heavy load electric rail trolley in automatic port. Smooth starting/braking and precise positioning is necessary for power-driven rail trolley. This paper presents the soft start scheme and the “double stop” scheme in braking process. In the first stop process, the trolley speed is reduced using variable frequency speed control system. For the second stop process, mechanical braking is adopted for precision locating. Considering wheel-rail adhesion, the trolley braking acceleration is determined. Analysis shows soft start is able to achieve balance between acceleration and running stability of trolley, and “double stop” scheme can not only stop stably, but also achieve precise locating.

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Transient response analysis of the variable frequency cropping system

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406jmes577 ◽

2007 ◽

Vol 221 (7) ◽

pp. 769-778

Author(s):

Z W Wang ◽

S D Zhao ◽

Y T Yu ◽

L J Zhang

Keyword(s):

Dynamic Analysis ◽

Cropping System ◽

Green Manufacturing ◽

Element Model ◽

Vibration Characteristics ◽

Test Method ◽

Response Analysis ◽

Variable Frequency ◽

Lumped Mass ◽

Orthogonal Test Method

Variable frequency cropping is a new type of green manufacturing technology that utilizes the forced vibration of a cropping machine and the stress concentration effect of a V-shaped notch to produce crack initiation and propagation. In this paper, dynamic analysis of a variable frequency vibration cropping system is performed. First, the working principle and components of a variable frequency cropping system are explained. Further analysis shows that vibration characteristics are the main subject of variable frequency cropping. Second, the orthogonal test method is adopted to assess the influence of geometric parameters of the V-shaped notch on the vibration characteristics of metal bars. The results indicate that a V-shaped notch has little effect on the vibration mode frequency. Third, a finite-element model of the cropping system is constructed, which is composed of rigid bar elements, a beam element, a lumped mass element, and spring elements. Then the modal and dynamic analyses are conducted. The vibration characteristics and the ideal cropping frequency range are obtained on the basis of the results of the dynamic analysis. Finally, cropping experiments on bars made of Al-Cu4MgSi, C45e, C20e, and TC80 are carried out under conditions of three variable frequency curves.

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Microfabrication research at the National Submicron Facility

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074331 ◽

1983 ◽

Vol 41 ◽

pp. 86-89

Author(s):

E.D. Wolf

Keyword(s):

Integrated Circuits ◽

Particle Physics ◽

High Speed ◽

New Technology ◽

High Energy ◽

High Energy Particle ◽

New Science ◽

Wide Range ◽

Intermediate Domain ◽

Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

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Vacuum System to Minimize the Specimen Contamination of High-Performance EM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077967 ◽

1977 ◽

Vol 35 ◽

pp. 68-69

Author(s):

N. Yoshimura ◽

K. Shirota ◽

T. Etoh

Keyword(s):

Electron Microscope ◽

High Speed ◽

High Performance ◽

High Vacuum ◽

Vacuum System ◽

Pump System ◽

Pumping System ◽

Diffusion Pump ◽

Almost All ◽

Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

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