Movement characteristics analysis of bi-directional friction linear micro-motor driven by a set of micro-actuator

2021 ◽  
pp. 2140013
Author(s):  
Zhenlu Wang ◽  
Jiue Zhang ◽  
Shuxia Ma ◽  
Guangqiao Liu
Keyword(s):  
Driving Frequency ◽  
Dynamics Model ◽  
Motion Direction ◽  
Movement Characteristics ◽  
Theoretical Predictions ◽  
Characteristics Analysis ◽  
Directional Motion ◽  
The Impact ◽  
Theoretical Results ◽  
Good Agreement

In this paper, a bi-directional friction linear micro-motor (BFLM) driven by a set of micro-actuators was introduced and analyzed. The BFLM was fabricated using PolyMUMPs process. The impact dynamics model for the BFLM was established, and its motion equation was also derived that takes into account the friction and contact. The relative motion between the driving head and the slider, as well as forward or backward movement of the slider were analyzed in detail. The forward and backward movement displacement of the slider was measured, and the experimental results were in good agreement with theoretical predictions. The theoretical results show that the motion direction of the slider can be changed by controllable driving frequency to the BFLM. It was feasible to use a set of actuators to drive the slider in bi-directional motion.

Thermal Behavior and Friction in Journal Bearings

1970 ◽  
Vol 92 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Al. Nica
Keyword(s):  
Experimental Data ◽  
Thermal Behavior ◽  
Heat Dissipation ◽  
Journal Bearings ◽  
Friction Torque ◽  
Operating Characteristics ◽  
Lubricant Flow ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

This paper deals with friction and the field of temperature in the lubricant film of journal bearings. Theoretical results regarding the thermal behavior are checked with experimental data and good agreement is found. Emphasis is put on the variation of temperature and lubricant flow with the operating characteristics of the bearing and it is seen that theoretical predictions for minima of friction torque are backed by temperature measurements. Further on, the friction torque and the mechanism of heat dissipation in bearings are dealt with, in order to verify the assumptions used in the calculation schemes. The means of efficiently cooling the bearing are also discussed, as well as the part played by the divergent zone in this process.

Thermal modelling and optimization of heat transfer in a high-temperature theatre luminaire

2003 ◽  
Vol 217 (9) ◽  
pp. 1039-1048 ◽  
Author(s):  
D E Anderson ◽  
T E Truslove ◽  
J Kubie
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Dynamics Model ◽  
Critical Temperatures ◽  
Computational Fluid Dynamics Model ◽  
Extended Surfaces ◽  
Theoretical Results ◽  
Modelling And Optimization ◽  
Good Agreement ◽  
Appreciable Reduction

A computational fluid dynamics model has been developed to predict the thermal performance of high-temperature theatre luminaires. The theoretical results are in good agreement with available experimental data. The model has been used to investigate the behaviour of the thermally sensitive areas of the luminaires. The model shows that an appreciable reduction of critical temperatures can be achieved by using extended surfaces at key locations. The model can also be used to evaluate and optimize future designs.

On the Dynamics of a Rotary Compressor: Part 2 — Experimental Validation and Sensitivity Analysis

1993 ◽  
Author(s):  
Sisir K. Padhy
Keyword(s):  
Experimental Validation ◽  
Sensitivity Study ◽  
Rotary Compressor ◽  
Dynamics Model ◽  
The Coefficient Of Friction ◽  
The Moment ◽  
Discharge Pressure ◽  
Roller Radius ◽  
Theoretical Results ◽  
Good Agreement

Abstract This paper describes the experimental validation of the rotary compressor dynamics model [1]. Roller velocity is measured using video technology and a very good agreement is found with the theoretical results. A sensitivity study using different variables that affect the compressor dynamics is also carried out. It is found that the coefficient of friction at the vane and roller plays an important role in roller velocity. The dynamics of roller is influenced by the clearances, the roller radius, the vane radius, eccentricity of the shaft, the frictional behavior between the roller ends and the bearing plates, the discharge pressure of the compressor as well as the moment of inertia of roller.

Air Impact Drive for Positioning by Pulse and Continuous Air Pressure

1999 ◽  
Vol 11 (4) ◽  
pp. 263-268 ◽  
Author(s):  
Mohammad Hossein Kouklan ◽  
◽  
Yousef Hojjat ◽  
Toshiro Higuchi ◽  
Keyword(s):  
Pulse Pressure ◽  
Air Pressure ◽  
Impulsive Force ◽  
Precise Positioning ◽  
Good Linearity ◽  
Free Body ◽  
The Impact ◽  
Theoretical Results ◽  
Good Agreement

In recent years, the application of impacts to precise positioning has been increased. Previously, the impulsive force or impact was generated by electromagnetic impulsive force or by the sudden deformation of a piezoelement. In this paper, a new actuator named as Air Impact Drive (AID) is introduced, in which the impact is generated by impulsive air pulse pressure. Free body diagrams and equations of this new actuator were drawn and determined. Experimental and theoretical results are in good agreement. The new actuator could displace a 0.2kg object at 0.1 of millimeter per pulse by pulse air pressure. By implementing suitable setup of parameters, the AID could move the object by continuous, constant air pressure with good linearity. This property is unique among other impact drives for positioning. By 0.3Mpa of source air pressure, the new actuator could move the mentioned object at the speed of approximately 13.4mm/s.

Beam-foil spectroscopy of oxygen in the wavelength region from 270 to 490 Å

1978 ◽  
Vol 56 (5) ◽  
pp. 508-516 ◽  
Author(s):  
Eric H. Pinnington ◽  
Keith E. Donnelly ◽  
J. Anthony Kernahan ◽  
David J. G. Irwin
Keyword(s):  
Satisfactory Agreement ◽  
Wavelength Region ◽  
Theoretical Predictions ◽  
The Mean ◽  
Theoretical Results ◽  
Beam Foil ◽  
Foil Technique ◽  
Good Agreement

We have used the beam-foil technique to study the spectrum of oxygen between 270 and 490 Å. We have measured the mean lives of the 3d2F, 3d4P, 3d4D, 3d′ 2D, 3d′ 2F, 4d4P, and 4d4D terms of O II, the 3s1P0, 3s3P0, 3S5P, 3s′ 3D, 3d3P, 3d3D, 3d3F, and 3d5P terms of O III, and the 3S2S, 3P2P0, and 3s4P0 terms of O IV. All cascade components are adequately explained. Good agreement is found with previous measurements in most cases, but significant discrepancies are found with some earlier results obtained using branches above 2000 Å. Generally satisfactory agreement is also found with theoretical predictions, although disagreement is found for several members of the 2p3–2p23d array in O II f-Values are computed for 18 individual lines, and compared with other experimental and theoretical results. Finally, we discuss briefly the f-value trends along the 2p23P–2p3s3P0 (O III), 2p21D–2p3s1P0 (O III), 2s2p24P–2s2p(3P0)3s4P0 (O IV), and 2p2P0–3s2S (O IV) isoelectronic sequences.

Temporal instability modes of supersonic round jets

2010 ◽  
Vol 662 ◽  
pp. 173-196 ◽  
Author(s):  
LUIS PARRAS ◽  
STÉPHANE LE DIZÈS
Keyword(s):  
A Priori ◽  
Temporal Stability ◽  
Jet Noise ◽  
Base Flow ◽  
Round Jets ◽  
Instability Modes ◽  
Theoretical Predictions ◽  
Mode Characteristics ◽  
The Impact ◽  
Good Agreement

In this study, a comprehensive inviscid temporal stability analysis of a compressible round jet is performed for Mach numbers ranging from 1 to 10. We show that in addition to the Kelvin–Helmholtz instability modes, there exist for each azimuthal wavenumber three other types of modes (counterflow subsonic waves, subsonic waves and supersonic waves) whose characteristics are analysed in detail using a WKBJ theory in the limit of large axial wavenumber. The theory is constructed for any velocity and temperature profile. It provides the phase velocity and the spatial structure of the modes and describes qualitatively the effects of base-flow modifications on the mode characteristics. The theoretical predictions are compared with numerical results obtained for an hyperbolic tangent model and a good agreement is demonstrated. The results are also discussed in the context of jet noise. We show how the theory can be used to determine a priori the impact of jet modifications on the noise induced by instability.

scholarly journals Generalized Softened Variable Angle Truss Model for RC Hollow Beams under Torsion

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2209
Author(s):  
Luís Bernardo
Keyword(s):  
Solution Procedure ◽  
Pure Torsion ◽  
Specific Behavior ◽  
Torsional Response ◽  
Truss Model ◽  
Variable Angle ◽  
Theoretical Predictions ◽  
Hollow Beams ◽  
Theoretical Results ◽  
Good Agreement

In recent studies, a new softened truss model called Generalized Softened Variable Angle Truss Model (GSVATM) has been proposed to compute the full torsional response of reinforced concrete (RC) rectangular solid beams under pure torsion. In this article, the GSVATM is extended to cover RC hollow beams under torsion. The modification of the calculation procedure, in order to account for the specific behavior of RC hollow beams for low loading levels, as well as the final solution procedure, is presented. The theoretical predictions from the extended GSVATM are compared with experimental results of RC hollow beams under torsion found in the literature. Good agreement is observed between the experimental and theoretical results, for both high and low loading levels.

Comparison Between Theoretical Predictions of Wave Resistance and Experimental Data for the Wigley Hull

1983 ◽  
Vol 27 (04) ◽  
pp. 215-226
Author(s):  
C. Y. Chen ◽  
F. Noblesse
Keyword(s):  
Experimental Data ◽  
Froude Number ◽  
Resistance Coefficient ◽  
Wave Resistance ◽  
Number Range ◽  
Theoretical Predictions ◽  
Wigley Hull ◽  
Sinkage And Trim ◽  
Theoretical Results ◽  
Good Agreement

A number of theoretical predictions of the wave-resistance coefficient of the Wigley hull are compared with one another and with available experimental data, to which corrections for sinkage and trim are applied. The averages of eleven sets of experimental data (corrected for sinkage and trim) and of eleven sets of theoretical results for large values of the Froude number, specifically for F 0.266, 0.313, 0.350, 0.402, 0.452, and 0.482, are found to be in fairly good agreement, in spite of considerable scatter in both the experimental data and the numerical results. Furthermore, several sets of theoretical results are fairly close to the average experimental data and the average theoretical predictions for these large values of the Froude number. Discrepancies between theoretical predictions and experimental measurements for small values of the Froude number, specifically for F = 0.18, 0.20, 0.22, 0.24, and 0.266, generally are much larger than for the above-defined high-Froude-number range. However, a notable exception to this general finding is provided by the first-order slender-ship approximation evaluated in Chen and Noblesse [1],3 which is in fairly good agreement with the average experimental data over the entire range of values of Froude number considered in this study.

scholarly journals Experiment and Analysis on the Free Dynamics of a Shallow Arch After an Impact Load at the End

2005 ◽  
Vol 72 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Jen-San Chen ◽  
Chun-Yi Liao
Keyword(s):  
Transient Response ◽  
Impact Load ◽  
Minimum Energy ◽  
The Other ◽  
Initial Speed ◽  
Attached Mass ◽  
Shallow Arch ◽  
Theoretical Predictions ◽  
The Impact ◽  
Good Agreement

In this paper we consider a sinusoidal arch with one end pinned in space while the other end attached to a mass and supported by a spring. The supporting wall of the spring is moved a distance quasi-statically to initiate preload in the arch and the spring. The assembly is then set in motion by an impact at the attached mass. The condition under which the arch may snap to the other side dynamically depends on the initial speed of the attached mass due to impact. Sufficient condition on the initial speed against dynamic snap-through is formulated based on the concept of minimum energy barrier. The effects of damping on the transient response of the assembly are also discussed. An experimental setup is designed to measure the transient response of the arch following the impact and the critical initial speed of the attached mass. The experimental results are in good agreement with theoretical predictions.

Laminar Free Convection From a Downward-Projecting Fin

1968 ◽  
Vol 90 (1) ◽  
pp. 63-70 ◽  
Author(s):  
G. S. H. Lock ◽  
J. C. Gunn
Keyword(s):  
Boundary Layer ◽  
Free Convection ◽  
Prandtl Number ◽  
Experimental Program ◽  
Boundary Layer Problem ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement ◽  
Quiescent Fluid

A theoretical analysis of conduction through and free convection from a tapered, downward-projecting fin immersed in an isothermal quiescent fluid is presented. The problem is solved by assuming quasi-one-dimensional heat conduction in the fin and matching the solution to that of the convection system, which is treated as a boundary layer problem. For an infinite Prandtl number, solutions are derived which take the form of a power law temperature distribution along the fin. The effect of this power (n) on heat transfer, drag, and the corresponding boundary layer profiles is discussed. It is shown that n is independent of the fin profile and dependent on a single nondimensional group χ. The theoretical results for infinite Prandtl number are compared with corresponding results derived from previous work using a Prandtl number of unity. The effect of Prandtl number on the determination of n and consequently the fin effectiveness is found to be extremely small. The results of an experimental program are also presented. These consist of temperature profiles and the n — χ relation for different fin geometries and surrounding fluids. Comparison with the theoretical predictions reveals good agreement.

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