scholarly journals Substantiation of inertial, stiffness and excitation parameters of vibratory lapping machine with linear oscillations of laps

2018 ◽  
Vol 4 (2) ◽  
pp. 26-39 ◽  
Author(s):  
Ihor Kuzio ◽  
◽  
Viktor Zakharov ◽  
Vitaliy Korendiy ◽  
◽  
...  
Keyword(s):  
Lapping Machine ◽  
Excitation Parameters

Analysis of structures of flat planting machines

2021 ◽  
Vol 13 (1) ◽  
pp. 140-148
Author(s):  
Andrіі Slabkyі ◽  
◽  
Olexandr Manzhilevskyy ◽  
Olexandr Polishchuk ◽  
◽  
...  
Keyword(s):  
Cutting Tool ◽  
Relative Movement ◽  
Statistical Parameters ◽  
Abrasive Finishing ◽  
Wide Range ◽  
Uneven Wear ◽  
Lapping Machine ◽  
Numerical Program ◽  
Hydraulic Pulse

One of the methods of material processing is considered, which allows to obtain high geometric accuracy and low surface roughness of parts, namely their abrasive finishing. The high quality of machining of parts in this way is due to the use of coordinated relative movement of the workpiece and the cutting tool. According to the kinematic features, most lapping machines can be divided into two groups: machines with oscillating working motion and machines with rotating lapping motion. The machines of the first group are more common due to the simplicity of their design and versatility. However, the possibility of their use is limited by the size range of the workpieces and uneven wear of the cutting tool and, as a consequence, the uneven surface treatment of the part. The machines of the second group are considered the most versatile, as they allow processing a wide range of parts, varying in shape and size, but they are also not without such a disadvantage as uneven wear of the cutting tool with all the corresponding consequences. Improving the efficiency of abrasive finishing by complicating the trajectory of the relative movement of the tool and the part, ie the formation of a unique mutual working movement of the lapping and the movement of the workpiece, is one of the most common areas. The main disadvantage of equipment that provides processing of parts on this principle is, in most cases, limited regulation of the operating parameters of the cutting process, so this area remains promising and has broad prospects for development. The constructive scheme of the hydraulic-pulse flat-lapping machine offered in work thanks to a combination of advantages of the hydraulic-pulse drive with use of numerical program control will allow to provide unique mutual multi-movement of preparation and the lapping tool with a possibility of adjustment of its parameters in the course of processing. Purposeful choice of the shape and density of the trajectory of the working movement of the tool will form a micro relief of the treated surface with the necessary statistical parameters and low roughness.

Engineering of a lapping machine with a cycloidal toolpath

2019 ◽  
pp. 54-59
Author(s):  
Karim Ravilevich Muratov ◽  
Evgeny Anatolyevich Gashev ◽  
Daria Petrovna Ismailova
Keyword(s):  
Lapping Machine

Modeling and Analysis of an Optically-Actuated, Bistable MEMS Device

2010 ◽  
Author(s):  
Vijay Kumar ◽  
Jeffrey F. Rhoads
Keyword(s):  
Transient Behavior ◽  
Distributed Parameter ◽  
Mems Devices ◽  
Lumped Mass ◽  
Modeling And Analysis ◽  
Mems Switch ◽  
The Rich ◽  
Predictive Design ◽  
Commercial Applications ◽  
Excitation Parameters

Bistable microsystems have drawn considerable interest from the MEMS/NEMS research community not only due to their broad applicability in commercial applications, such as switching, but also because of the rich dynamic behavior they commonly exhibit. While a number of prior investigations have studied the dynamics of bistable microsystems, comparatively few works have sought to characterize their transient behavior. The present effort seeks to address this through the modeling and analysis of an optically-actuated, bistable MEMS switch. The work begins with the development of a distributed-parameter representation for the system, which is subsequently reduced to a lumped-mass analog and analyzed through the use of numerical simulation. The influence of various system and excitation parameters, including the applied axial load and optical actuation profile, on the system’s transient response is then investigated. Ultimately, the methodologies and results presented herein should provide for a refined predictive design capability for optically-actuated, bistable MEMS devices.

Study on Vibration Reduction of Finishing Lapping Machine for Bearing Race

2011 ◽  
Vol 199-200 ◽  
pp. 1496-1500
Author(s):  
Jia Man ◽  
Lian Hong Zhang ◽  
Yong Liang Chen
Keyword(s):  
Vibration Amplitude ◽  
Vibration Reduction ◽  
Experimental Studies ◽  
Machining Efficiency ◽  
Bearing Race ◽  
Excitation Force ◽  
Lapping Machine ◽  
Light Material ◽  
Vibration Performance

It is key to improve the machining efficiency of finishing lapping machine to restrain the vibration that raise with work speed. The vibration amplitude is influenced by the excitation force of unbalanced crank-rocker mechanism and the anti-vibration performance of guide. Following improving schemes as adding counterweight to crank-rocker mechanism, adopting the light material motion components and enhancing the anti-vibration performance of guide are proposed based on theoretical and experimental studies. The improving schemes are verified by the experiment.

scholarly journals Enhancing the Performance of DFIG Wind Turbines Considering Excitation Parameters of the Insulated Gate Bipolar Transistors and a New PLL Scheme

2021 ◽  
Vol 8 ◽  
Author(s):  
Kenneth E. Okedu ◽  
Hind F. A. Barghash
Keyword(s):  
Power System ◽  
Wind Turbine ◽  
Control Strategy ◽  
Computer Aided Design ◽  
Transient State ◽  
Power Converter ◽  
Bipolar Transistors ◽  
Insulated Gate Bipolar Transistors ◽  
Wind Generator ◽  
Excitation Parameters

The major aim for achieving the successful synchronization of a wind turbine system to the grid is to mitigate electrical and mechanical stresses on the wind generator. During transient state, the gearbox, shaft, and rotor of the wind generator could be damaged due to mechanical stress. The rotor and stator windings of the wind generator, including its insulation, could be affected. This paper undertakes an extensive analysis of the effects of the excitation parameters of the power converter Insulated Gate Bipolar Transistors (IGBTs), on the transient state performance of the Doubly Fed Induction Generator (DFIG), considering different scenarios. The optimal excitation parameters of IGBTs were used for further analysis of the wind generator, considering a new Phase-Locked-Loop (PLL) scheme. The PLL computes the phase displacement of the grid required to achieve orientation and synchronization control. Consequently, it helps in preventing power system distortion due to stator-grid interphase. This paper proposes a new approach that integrates PLL control strategy and a Series Dynamic Braking Resistor (SDBR) to augment the fault ride through capability of a variable speed wind turbine that is DFIG-based. The SDBR helps the post fault recovery of the wind generator. Simulations were run in Power System Computer Aided Design and Electromagnetic Transient state Including DC (PSCAD/EMTDC) to examine severe fault conditions, and to test the robustness of the controllers employed. The results show that the proposed hybrid control strategy aids the fast recovery of the DFIG wind generator variables during fault conditions.

Modeling and Analysis of an Optically-Actuated, Bistable MEMS Device

2012 ◽  
Vol 7 (2) ◽  
Author(s):  
Vijay Kumar ◽  
Jeffrey F. Rhoads
Keyword(s):  
Transient Behavior ◽  
Distributed Parameter ◽  
Mems Devices ◽  
Lumped Mass ◽  
Modeling And Analysis ◽  
Mems Switch ◽  
The Rich ◽  
Predictive Design ◽  
Commercial Applications ◽  
Excitation Parameters

Bistable microsystems have drawn considerable interest from the MEMS/NEMS research community not only due to their broad applicability in commercial applications, such as switching, but also because of the rich dynamic behavior they commonly exhibit. While a number of prior investigations have studied the dynamics of bistable microsystems, comparatively few works have sought to characterize their transient behavior. The present effort seeks to address this through the modeling and analysis of an optically-actuated, bistable MEMS switch. This work begins with the development of a distributed-parameter representation for the system, which is subsequently reduced to a lumped-mass analog and analyzed through the use of numerical simulation. The influence of various system and excitation parameters, including the applied axial load and optical actuation profile, on the system’s transient response is then investigated. Ultimately, the methodologies and results presented herein should provide for a refined predictive design capability for optically-actuated, bistable MEMS devices.

scholarly journals The Energy Compensation of the HRG Based on the Double-Frequency Parametric Excitation of the Discrete Electrode

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3549
Author(s):  
Wanliang Zhao ◽  
Hao Yang ◽  
Fucheng Liu ◽  
Yan Su ◽  
Lijun Song
Keyword(s):  
Parametric Excitation ◽  
Dynamical Equation ◽  
Dynamic Performance ◽  
Free Precession ◽  
Double Frequency ◽  
Energy Compensation ◽  
Hemispherical Resonator ◽  
The Stability ◽  
Resonator Vibration ◽  
Excitation Parameters

In this study, for energy compensation in the whole-angle control of Hemispherical Resonator Gyro (HRG), the dynamical equation of the resonator, which is excited by parametric excitation of the discrete electrode, is established, the stability conditions are analyzed, and the method of the double-frequency parametric excitation by the discrete electrode is derived. To obtain the optimal parametric excitation of the resonator, the total energy stability of the resonator is simulated for the evolution of the resonator vibration with different excitation parameters and the free precession of the standing wave by the parametric excitation. In addition, the whole-angle control of the HRG is designed, and the energy compensation of parametric excitation is proven by the experiments. The results of the experiments show that the energy compensation of the HRG in the whole-angle control can be realized using discrete electrodes with double-frequency parametric excitation, which significantly improves the dynamic performance of the whole-angle control compared to the force-to-rebalance.

General Method for Analyzing Refractory-Metal Alloys Using the Vacuum-Cup Electrode

1966 ◽  
Vol 20 (6) ◽  
pp. 400-403 ◽  
Author(s):  
Elizabeth C. Leao ◽  
E. W. Hobart ◽  
D. E. Fornwalt
Keyword(s):  
Sulfuric Acid ◽  
Refractory Metal ◽  
Metal Alloys ◽  
Sample Weight ◽  
Coefficients Of Variation ◽  
Permit Application ◽  
Refractory Metal Alloys ◽  
Excitation Parameters ◽  
Oxalic Acids ◽  
General Method

The application of the vacuum-cup electrode to the spectrographs analysis of solutions of refractory-metal alloys is described. Both citric and oxalic acids in 5% sulfuric acid solution served as suitable completing agents. The absence of interelement effects is demonstrated. Alternate sets of excitation parameters and variation of sample weight and aliquot sizes permit application of the technique to a broad range of element concentrations. Typical coefficients of variation of results obtained by the method are between 3% and 4%.

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