Dynamic Modeling and Performance Evaluation of a Vibrating Cantilever Beam Microgyroscope

2005 ◽  
Author(s):  
Mehdi Esmaeili ◽  
Mohammad Durali ◽  
Nader Jalili
Keyword(s):  
Performance Evaluation ◽  
Dynamic Modeling ◽  
Input Parameter ◽  
Galerkin Approximation ◽  
Linear Functions ◽  
System Sensitivity ◽  
Beam Displacement ◽  
Overall Performance ◽  
And Performance ◽  
Tip Mass

This paper discusses the effects of substrate motions on the performance of microgyroscopes modeled as suspended beams with a tip mass. The substrate movements can be motions along as well as rotations around the three axes. Using Extended Hamiltonian Principle and Galerkin approximation, the equations of the motion of the beam are analytically derived. In these equations, the effects of beam distributed mass, tip mass, angular accelerations, centripetal and coriolis accelerations are clearly apparent. The effect of electrostatic forces inducing the excitation vibrations are considered as linear functions of beam displacement. The response of the system to different inputs is studied and the system sensitivity to input parameter changes are examined. Finally, the sources of error in the measurement of rotation rate input are recognized. The study demonstrated the importance of errors caused by cross axes inputs on the gyroscope output measurements and overall performance.

Ring Microgyroscope Modeling and Performance Evaluation

2005 ◽  
Author(s):  
Mehdi Esmaeili ◽  
Mohammad Durali ◽  
Nader Jalili
Keyword(s):  
Performance Evaluation ◽  
Differential Equations ◽  
Input Parameter ◽  
Equations Of Motion ◽  
Galerkin Approximation ◽  
Ring Structure ◽  
Frequency Equation ◽  
System Sensitivity ◽  
Extended Hamilton’S Principle ◽  
And Performance

This paper discusses the effects of substrate motions on the performance of a microgyroscope modeled as a ring structure. Using Extended Hamilton’s Principle, the equations of motion are derived. The natural frequency equation and response of gyroscope are then extracted in closed-form for the case where substrate undergoes normal rotation. The Galerkin approximation is used for discretizing the partial differential equations of motion into ordinary differential equations. In these equations, the effects of angular accelerations, centripetal and coriolis accelerations are well apparent. The response of the system to different inputs is studied and the system sensitivity to input parameter changes is examined. Finally, the sources of error in the measurement of input rotational rate are recognized. The study demonstrates the importance of errors caused by cross axes inputs on the gyroscope output measurements.

Modeling and Vibration Analysis of Vibrating Beam Microgyroscopes Under Longitudinal Rotation of the Support

2005 ◽  
Author(s):  
Mehdi Esmaeili ◽  
Mohammad Durali ◽  
Nader Jalili
Keyword(s):  
Vibration Analysis ◽  
Input Parameter ◽  
Equations Of Motion ◽  
Linear Functions ◽  
Electrostatic Forces ◽  
System Sensitivity ◽  
Rotational Rate ◽  
Extended Hamilton’S Principle ◽  
Beam Displacement ◽  
Tip Mass

This paper discusses the effects of substrate motions on the performance of a microgyroscope modeled as a suspended beam with a tip mass. These motions can be either along or around the three axes. Using the Extended Hamilton’s Principle, the equations of motion are derived. In these equations, the effects of beam distributed mass, tip mass, angular accelerations, centripetal and coriolis accelerations are well apparent. The effect of electrostatic forces inducing the excitation vibrations are considered as linear functions of beam displacement. The response of the system to different inputs is studied and the system sensitivity to input parameter changes are examined. Finally, the sources of error in the measurement of input rotational rate are investigated and identified. The study demonstrates the importance of errors caused by cross axes inputs on the gyroscope output measurements.

scholarly journals Development and Performance Evaluation of a Spring-Loaded Hand Operated Maize Sheller with Variable Mechanisms

2018 ◽  
Vol 15 ◽  
pp. 44-52 ◽  
Author(s):  
R. Segun Bello ◽  
C. Fabian
Keyword(s):  
Performance Evaluation ◽  
Moisture Content ◽  
Production Cost ◽  
Output Capacity ◽  
Corn Cobs ◽  
Machine Performance ◽  
Overall Performance ◽  
The Mean ◽  
And Performance ◽  
Mean Kernel

A spring-press, variable mechanism hand operated maize sheller was developed, constructed and tested with corn cobs at 12.6% moisture content, wet basis (w.b) and its shelling performances compared. The machine is lever operated with a spring load-return mechanism and a cob constrictor with changeable shelling mechanisms (spike tooth, rasp bar and star tooth), and a tilted tray for grain collection. The overall dimension of the machine is 520mm x 520mm x 400mm. The machine overall performance is 20.62kg/hr shelling capacity, 85.13% shelling efficiency and 2.13% kernel damage. Comparing the performance of the three shelling mechanisms; rasp bar, spike tooth and star tooth, shelling capacity (16.2, 26.0, 19.67) kg/hr.; shelling efficiency (82.22%, 87.19%, 85.97%); and % kernel damage (0.00, 0.74, 0.51) respectively, the star mechanism has a higher capacity of 26.0kg/hr. The mean kernel damage is higher for star tooth, whereas it is zero for rasp bar. In comparison with conventional hand-palm shelling method (100% shelling efficiency, 13.83kg/hr shelling capacity and 0% kernel damage), the hand operated sheller has a better output capacity, reasonable shelling efficiency but slightly higher kernel damage. By implication, machine performance efficiency does not give a true reflection of how effective a system work until the machine capacity is determined. The sheller ease household shelling maize for consumption with initial low production cost of N13, 100.00 (~$30).

An integrated framework for supplier selection and performance evaluation for apparel retail industry

2021 ◽  
pp. 004051752199235
Author(s):  
Canan Sarıçam ◽  
Said Melih Yilmaz
Keyword(s):  
Performance Evaluation ◽  
Supplier Selection ◽  
Numerical Data ◽  
Critical Issue ◽  
Global Market ◽  
Integrated Framework ◽  
Overall Performance ◽  
And Performance ◽  
Qualitative Performance ◽  
Apparel Retailers

Supplier evaluation, including supplier selection and performance evaluation, has become a critical issue for apparel retailers within the apparel supply chain dealing with severe competition in the global market. An effective evaluation of suppliers requires considering both the quantitative and qualitative performance aspects and integrating the efficiency measurement. In an attempt to address this issue, this study proposes an integrated framework that can handle supplier selection and overall performance evaluation in a comprehensive but feasible manner. The proposed integrated framework customized for apparel retailers combines the current techniques having specific capabilities: data envelopment analysis (DEA), analytical hierarchy process (AHP), and the technique for order preference by similarity to ideal solution (TOPSIS). DEA has been used to make the overall performance evaluation, whereas AHP and TOPSIS have been used in combination to provide the quantitative data required by DEA. The proposed integrated framework was implemented and verified using numerical data gathered from a global apparel retailer. The findings revealed that suppliers can be more successful when they put a balanced effort into improving their performance in regards to the important criteria instead of concentrating on only the most important criterion. Moreover, the overall performance evaluation can be much more convenient and rewarding for apparel retailers in terms of finding out the true potential of suppliers when quantitative and qualitative data and efficiency measurements are taken into account at the same time.

scholarly journals Experiments and Performance Evaluation of a Transonic Axial Flow Turbine With Variable Nozzle

1986 ◽  
Author(s):  
Toshiyuki Takagi
Keyword(s):  
Performance Evaluation ◽  
Surface Pressure ◽  
Axial Flow ◽  
Prediction Method ◽  
Pressure Distributions ◽  
Wide Range ◽  
Overall Performance ◽  
Transonic Turbine ◽  
Loss Systems ◽  
And Performance

To examine extensively the overall performance of a single-stage transonic turbine under high-loading conditions, aerodynamic experiments were conducted over a wide range of stage pressure ratios up to 4.16. The measured performance is estimated by means of a mean-line prediction method with two loss systems and is discussed with radial variations and surface pressure distributions. The results show that airflow characteristics, loss systems and choking Mach numbers play an important role in evaluating the performance when choking occurs at either row.

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