Smoothly Combining Steady State Predictions With PI Control

2012 ◽  
Author(s):  
David A. Hodgson ◽  
Peter M. Young ◽  
Charles W. Anderson ◽  
William S. Duff ◽  
Douglas C. Hittle ◽  
...  
Keyword(s):  
Steady State ◽  
Pi Control ◽  
Steady State Predictions

Analysis of an Accelerating Rotor-Bearing System With Flexible Damped Supports

1998 ◽  
Author(s):  
Euro L. Casanova ◽  
Luis U. Medina
Keyword(s):  
Steady State ◽  
Numerical Integration ◽  
Equations Of Motion ◽  
Peak Amplitude ◽  
Graphical Form ◽  
Jeffcott Rotor ◽  
Rotor Bearing ◽  
Flexible Supports ◽  
Steady State Predictions ◽  
Bearing System

This paper deals with the dynamics of an accelerating unbalanced Jeffcott rotor-bearing system mounted on damped, flexible supports. The general equations of motion for such a system are presented and discussed. The rotor response was predicted, via numerical integration, for various cases in runup and rundown conditions and presented in graphical form. The effects of acceleration on the rotor peak amplitude and the speed at which the peak occurs is discussed and compared to steady state predictions.

A Study of Formation of Circulation Patterns in Laminar Unsteady Lid-Driven Cavity Flows Using PIV Measurement Techniques

2012 ◽  
Author(s):  
K. M. Akyuzlu ◽  
J. Farkas
Keyword(s):  
Steady State ◽  
Measurement Techniques ◽  
Reynolds Numbers ◽  
Working Fluid ◽  
Computational Fluid Mechanics ◽  
Square Cavity ◽  
Driven Cavity ◽  
Circulation Patterns ◽  
Piv Measurement ◽  
Steady State Predictions

An experimental study was conducted to observe/visualize, the formation of circulation patterns inside a square cavity due to the movement of a lid at constant velocity. Lid driven cavity flow is one of the benchmark studies used in the verification/improvement of CFD codes for internal flow applications/predictions. Previous work on this topic is primarily focused on improving the steady state predictions of the CFD codes using different numerical schemes and algorithms. Furthermore, almost all of the studies reported in computational fluid mechanics literature relates to steady state predictions of lid or shear driven flows. Experimental work that is reported in these studies is limited in scope and number. This paper reports on the measurements we made using Particle Image Velocimeter (PIV) technique to determine the flow field as it develops from stagnation to steady state inside a square cavity driven by a lid. For this purpose, we employed a 2-D PIV system, which uses a double-cavity, Nd:Yag laser to illuminate the test cavity. Experiments were conducted using water as the working fluid inside a square cavity that is one inch (25.4 mm) high and one inch wide. The depth of the cavity is five inches (127 mm) to ensure two-dimensional circulations patterns. Hollow glass sphere particles with 10 microns in diameter were used as seeding of the working fluid, water. Experiments were repeated for different lid velocities corresponding to lid Reynolds numbers (laminar to beginning of transition of turbulence.) Velocity fields were captured during the development of the circulations patters each being unique for the time of the measurement and value of the lid velocity. The center of the circulation pattern and its path inside the cavity is constructed from the captured images as steady state is attained. Also, the strength of the circulation (as manifested by the increase in the diameter of the circulation) is determined at different times for different Reynolds numbers.

scholarly journals Optimasi Fuzzy Supervisory Control pada Performa Matrix Converter Drive 3x3 di Empat Kuadran Operasi

2021 ◽  
Vol 9 (1) ◽  
pp. 31
Author(s):  
ERA PURWANTO ◽  
MENTARI PUTRI JATI ◽  
BAMBANG SUMANTRI ◽  
INDRA FERDIANSYAH ◽  
GAMAR BASUKI
Keyword(s):  
Steady State ◽  
Supervisory Control ◽  
System Performance ◽  
Harmonic Distortion ◽  
Matrix Converter ◽  
Motor Drive ◽  
Pi Control ◽  
Space Vector Modulation ◽  
Drive Motor ◽  
Vector Modulation

ABSTRAKTeknologi pengemudian motor dengan efisiensi tinggi serta untuk mencapai empat kuadran operasi menjadi perhatian pada bidang pengemudian elektrik. Matrix converter menjadi alternatif utama konverter drive motor karena keunggulan – keunggulannya. Walaupun matrix converter sebagai drive motor mempunyai kompleksitas tinggi, namun dengan dikombinasikan teknik Indirect Space Vector Modulation (ISVM) dapat menghasilkan kepresisian lebar pulsa modulasi (PWM). Untuk pengendali sistem, diterapkan Fuzzy Supervisory Control (FSC), yang merupakan kendali gabungan, agar kecepatan referensi bisa tercapai. FSC dibandingkan dengan kendali konvensional (PI control) untuk membuktikan keoptimalan performa sistem yang diusulkan. Parameter performa sistem dan Total Harmonic Distortion (THD) dianalisis lebih lanjut. Hasil simulasi menunjukkan bahwa sistem yang diusulkan dapat mencapai Error Steady state (ESS) 0% dan THD lebih kecil.Kata kunci: Matrix converter, ISVM, FSC, motor induksi. ABSTRACTMotor-driving technology with high efficiency and to achieve four quadrants of operation is a concern in the area of electric steering. Matrix converter is the main alternative for motor drive converters because of its advantages. Although the matrix converter as a motor drive has a high complexity, combined with the Indirect Space Vector Modulation (ISVM) technique can produce precision pulse width modulation (PWM). For the system controller, Fuzzy Supervisory Control (FSC) is applied, which is a combined control, so that the reference speed can be achieved. FSC is compared with conventional control (PI control) to prove the optimization of the proposed system performance. System performance parameters and Total Harmonic Distortion (THD) are further analyzed. Simulation results show that the proposed system can reach 0% Error Steady State (ESS) and smaller THD.Keywords: Matrix converter, ISVM, FSC, induction motor.

scholarly journals Soft Elbow Exoskeleton for Upper Limb Assistance Incorporating Dual Motor-Tendon Actuator

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1184 ◽  
Author(s):  
Rifky Ismail ◽  
Mochammad Ariyanto ◽  
Inri A. Perkasa ◽  
Rizal Adirianto ◽  
Farika T. Putri ◽  
...  
Keyword(s):  
Steady State ◽  
Upper Limb ◽  
Elbow Flexion ◽  
Pi Control ◽  
Test Results ◽  
Wrist Motion ◽  
Dc Motors ◽  
Flexion Extension ◽  
Actuator System

Loss of muscle functions, such as the elbow, can affect the quality of life of a person. This research is aimed at developing an affordable two DOF soft elbow exoskeleton incorporating a dual motor-tendon actuator. The soft elbow exoskeleton can be used to assist two DOF motions of the upper limb, especially elbow and wrist movements. The exoskeleton is developed using fabric for the convenience purpose of the user. The dual motor-tendon actuator subsystem employs two DC motors coupled with lead-to-screw converting motion from angular into linear motion. The output is connected to the upper arm hook on the soft exoskeleton elbow. With this mechanism, the proposed actuator system is able to assist two DOF movements for flexion/extension and pronation/supination motion. Proportional-Integral (PI) control is implemented for controlling the motion. The optimized value of Kp and Ki are 200 and 20, respectively. Based on the test results, there is a slight steady-state error between the first and the second DC motor. When the exoskeleton is worn by a user, it gives more steady-state errors because of the load from the arm weight. The test results demonstrate that the proposed soft exoskeleton elbow can be worn easily and comfortably by a user to assist two DOF for elbow and wrist motion. The resulted range of motion (ROM) for elbow flexion–extension can be varied from 90° to 157°, whereas the maximum of ROM that can be achieved for pronation and supination movements are 19° and 18°, respectively.

Virus Transmission Through Compromised Synthetic Barriers: Part I—Effect of Unsteady Driving Pressures

2001 ◽  
Vol 123 (5) ◽  
pp. 506-512 ◽  
Author(s):  
Matthew R. Myers ◽  
Bigyani Das
Keyword(s):  
Steady State ◽  
Virus Transmission ◽  
Time Varying ◽  
Virus Suspension ◽  
Synthetic Membranes ◽  
Virus Adsorption ◽  
Barrier Surface ◽  
Number Of Cycles ◽  
Static Conditions ◽  
Steady State Predictions

Although synthetic membranes such as gloves, condoms, and instrument sheaths are used in environments with highly time-varying stresses, their effectiveness as barriers to virus transmission is almost always tested under static conditions. In this paper it is shown how a previously developed mathematical model can be used to transform information from static barrier tests into predictions for more realistic use conditions. Using a rate constant measured for herpes adsorption to latex in saline, and an oscillatory trans-membrane pressure representative of coitus, the amount of virus transmitted through a hole (2 μm diameter) in a condom is computed. Just beyond the exit orifice of the pore, transport is dominated by the rapidly dissipating viscous jet of virus suspension, which results in an accumulation of viruses roughly 20 pore radii from the barrier surface during each cycle. Due to virus adsorption to the barrier surfaces, the simulations reveal a gradual decrease in virus flow with increasing number of cycles, and thus a slow divergence from predictions based upon steady-state conditions. Still, over the 500 cycles simulated, steady-state predictions approximate the net number of viruses transmitted to within 25 percent error.

Quasi-Steady Laminar Film Condensation of Steam on Copper Spheres

1975 ◽  
Vol 97 (3) ◽  
pp. 347-351 ◽  
Author(s):  
V. K. Dhir
Keyword(s):  
Steady State ◽  
Saturation Temperature ◽  
Film Condensation ◽  
Average Heat Transfer Coefficient ◽  
Stagnant Water ◽  
Laminar Film ◽  
Laminar Film Condensation ◽  
Steady State Solutions ◽  
Steady State Predictions ◽  
Steady Laminar

An experimental study of laminar film condensation of steam on copper spheres of 1.90, 2.54, and 3.17 cm dia has been made. Experiments have been performed by submerging cold spheres in nearly stagnant water vapor at a saturation temperature of about 99° C. Values of Nusselt number based on average heat transfer coefficient are obtained for saturation to wall temperature differences of 5–65° C and for cp ΔT/hfg in the range of 0.009–0.12. The data are compared with the steady-state predictions of Dhir and Lien-hard and of Yang. Analysis has been made to show that it is valid to use steady-state solutions in quasi-steady condensation as long as the dimensionless thermal diffusion time constant is small, and the film does not move very slowly.

STEADY-STATE PREDICTIONS BASED ON FIRST DOSE DATA

1992 ◽  
Vol 15 ◽  
pp. 239A-240A
Author(s):  
W. Z. POTTER ◽  
C. LINDSAY DeVANE ◽  
M. V. RUDORFER
Keyword(s):  
Steady State ◽  
Steady State Predictions
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