Analysis of a Pneumatically Coupled Cam-Actuated Mechanism

1981 ◽  
Vol 103 (3) ◽  
pp. 290-292
Author(s):  
S. LeQuoc ◽  
R. M. H. Cheng
Keyword(s):  
Amplitude Ratio ◽  
Nonlinear Function ◽  
Design Tool ◽  
Lumped Parameter Model ◽  
Design Parameters ◽  
Damping Factor ◽  
Resonance Amplitude ◽  
Orifice Area ◽  
Lumped Parameter ◽  
Wear And Tear

Cam-actuated mechanism with a pneumtic coupling is a design improvement upon the conventional system. Pneumatic dashpots are used which provide a cushioning effect, thus reducing the wear and tear of system components. This paper investigates the dynamic behavior of such a system based on a lumped parameter model with a damping factor which is a nonlinear function of the frequency. A digital computer is used as a design tool to determine the effect on the performance of changing design parameters. It is found that the system amplitude ratio peak depends largely upon the pneumatic damper orifice area and that a proper selection of the orifice area will yield a minimum resonance amplitude ratio.

scholarly journals Lumped Parameter Model and Electromagnetic Performance Analysis of a Single-Sided Variable Flux Permanent Magnet Linear Machine

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5494
Author(s):  
Basharat Ullah ◽  
Faisal Khan ◽  
Muhammad Qasim ◽  
Bakhtiar Khan ◽  
Ahmad H. Milyani ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Thrust Force ◽  
Lumped Parameter Model ◽  
Computational Time ◽  
Design Parameters ◽  
3D Analysis ◽  
Flux Linkage ◽  
Lumped Parameter ◽  
Variable Flux ◽  
Linear Machine

A new Single-sided Variable Flux Permanent Magnet Linear Machine with flux bridge in mover core is proposed in this paper. The flux bridge prevents the leakage flux from the mover and converts it into flux linkage, which greatly influences the performance of the machine. First, a lumped parameter model is used to find the suitable coil combination and no-load flux linkage of the proposed machine, which greatly reduces the computational time and drive storage. Secondly, the proposed machine replaces the expensive rare earth permanent magnets with ferrite magnets and provides improved flux controlling capability under variable excitation currents. Multivariable geometric optimization is utilized to optimize the leading design parameters like split ratio, stator pole width, width and height of permanent magnet, flux bridge width, the width of mover’s tooth, and stator slot depth at constant electric and magnetic loading. The optimized design increases the flux linkage by 44.11%, average thrust force by 35%, thrust force density by 35.02%, minimizes ripples in thrust force by 23%, and detent force by 87.5%. Furthermore, the results obtained by 2D analysis are verified by 3D analysis. Thermal analysis is done to set the operating limit of the proposed machine.

scholarly journals Analysis of design parameters of round-window stimulating type electromagnetic transducer by a nonlinear lumped parameter model of implanted human ear

2022 ◽  
Vol 19 (3) ◽  
pp. 2453-2470
Author(s):  
Zhaohai Liu ◽  
◽  
Houguang Liu ◽  
Jie Wang ◽  
Jianhua Yang ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Round Window ◽  
Lumped Parameter Model ◽  
Design Parameters ◽  
Electromechanical Coupling Coefficient ◽  
Main Design ◽  
Lumped Parameter ◽  
Human Ear ◽  
Hearing Compensation

<abstract> <p>Round-window stimulating transducer is a new solution to treat mixed hearing loss. To uncover the factors affecting the round-window stimulation's performance, we investigated the influence of four main design parameters of round-window stimulating type electromagnetic transducer. Firstly, we constructed a human ear nonlinear lumped parameter model and confirmed its validity by comparing the stapes responses predicted by the model with the experimental data. Following this, an electromagnetic transducer's mechanical model, which simulates the floating mass transducer, was built and coupled to the human ear model; thereby, we established a nonlinear lumped parameter model of implanted human ear under round-window stimulation and verified its reliability. Finally, based on this model, the influences of the four main design parameters, i.e., the excitation voltage, the electromechanical coupling coefficient, the support stiffness, and the preload force, were analyzed. The results show that the change of excitation voltage does not alter the system's natural frequency. Chaotic motion occurs when the electromechanical coupling coefficient is small. Meanwhile, the stapes displacement appears to increase firstly and then decrease with the increase of the electromechanical coupling coefficient. The increase of the support stiffness enlarges the resonance frequency of the stapes displacement and reduces the stapes displacement near the resonance frequency, deteriorating the transducer's hearing compensation at low frequency. The preload force can improve the transducer's hearing compensation performance in mid-high frequency region.</p> </abstract>

Control Systems for Ultra-High Rise Elevators1

1998 ◽  
Vol 123 (4) ◽  
pp. 687-690
Author(s):  
S. R. Venkatesh ◽  
Y. M. Cho
Keyword(s):  
Exponential Stability ◽  
Control Systems ◽  
Global Exponential Stability ◽  
Control Design ◽  
Vertical Motion ◽  
Lumped Parameter Model ◽  
Performance Tests ◽  
High Rise ◽  
Lumped Parameter ◽  
Wear And Tear

We present a scalable and tunable control design for controlling elevator vertical motion for ultra high-rise buildings. Scalability is desirable to enable customization to any hoistway while tunability enables periodic adjustments to normal wear and tear. We accomplish these objectives by first validating a scalable lumped parameter model that is based on a few prominent features in the vertical dynamics. A tunable controller based only on these features is developed and through simulations we show that the controller meets a set of standardized elevator performance tests while maintaining global exponential stability.

scholarly journals CFD Simulation of a Post-Compensated Load Sensing Directional Control Valve

2021 ◽  
Vol 312 ◽  
pp. 05002
Author(s):  
Paola Fresia ◽  
Massimo Rundo
Keyword(s):  
Pressure Drop ◽  
Cfd Simulation ◽  
Control Valve ◽  
Design Tool ◽  
Lumped Parameter Model ◽  
Cfd Model ◽  
Load Sensing ◽  
Directional Control ◽  
Lumped Parameter ◽  
Directional Control Valve

The paper presents the CFD model of a load sensing directional control valve. The model was validated experimentally in terms of pressure drop and flow force at different positions of the spool. The spool position was imposed manually by means of a micrometric screw and a load cell was used for measuring the flow force. The CFD model was developed with the CAD-embedded tool FloEFD®. The model has been proved to be very reliable in estimating the pressure drop, moreover quite good results were obtained also in the evaluation of the flow force. The CFD simulations were used to tune the coefficients of a lumped parameter model of the valve, so that such a model can be efficiently used for the simulation of an entire hydraulic circuit. Moreover, the CFD model has been used as design tool for attenuating the detrimental effect of the flow force. In particular, the width of the land upstream of the metering edge has an influence on the resultant force on the spool. If was found that it is possible to significantly reduce the flow force at maximum opening with a relatively small increment of the pressure drop across the valve.

A Novel Design of a Self-Sensing Compensating Restrictor/Pad Module for Hydrostatic Bearings

2014 ◽  
Author(s):  
Cho-Yun Yang ◽  
Cho-Yu Yang ◽  
Jia-Wei Lu ◽  
Wei-Chih Lee ◽  
Yu-Min Hung ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Pressure Ratio ◽  
Lumped Parameter Model ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Hydrostatic Bearings ◽  
Lumped Parameter ◽  
Load Carrying ◽  
Membrane Type ◽  
The Relationship

This paper proposes the design of a self-sensing compensating restrictor/pad module for hydrostatic bearings. The module consists of a bearing pad and the associated restrictor featuring the characteristics of self-sensing compensation and easy installation. The paper first introduces the configuration of the proposed module. Then, the lumped parameter model was used to derive the equation for the relationship between the pocket pressure and the bearing gap. Furthermore, equations governing the stiffness and load-carrying capacity of the bearing were also obtained. Influences of the design parameters, such as the land length and pressure ratio, on bearing performance and the feasibility of the new design were studied both analytically and experimentally. Results of the theoretical analysis were compared with that of the experiment. Superior performances on the aspects of stiffness and load-carrying capacity, as well as time delay due to the distance between restrictor and bearing pad to the traditional restrictors such as capillary and orifice were achieved. In addition, the proposed restrictor possesses the advantages of simplicity for both manufacturing and assembly in comparison with the membrane-type restrictors.

scholarly journals A Distributed Lumped Parameter Model of Blood Flow

2020 ◽  
Vol 48 (12) ◽  
pp. 2870-2886
Author(s):  
Mehran Mirramezani ◽  
Shawn C. Shadden
Keyword(s):  
Blood Flow ◽  
Lumped Parameter Model ◽  
Lumped Parameter
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