Parameterization of a Piezoelectric Nanomanipulation Device

2006 ◽  
Author(s):  
Ravi Patel ◽  
Benjamin Legum ◽  
Yury Gogotsi ◽  
Bradley Layton
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Actuation Time ◽  
Normalized Error ◽  
Pick And Place ◽  
Fine Mode ◽  
Task Oriented ◽  
Speed And Accuracy

Through measurement of hysteresis and drift in a piezoelectrically driven multi-axis multi-positioner nanomanipulator, we have quantified error over ranges of three primary operating parameters: gain, duty cycle, and actuation time. A total of sixty-nine curves were plotted, and error and drift measured in a single operating plane. All data shown were collected on the Zyvex L-100 nanomanipulator operating in an open-loop programmed method, in both coarse (12mm range, 2–5 μm precision) and fine mode (100 μm range, 10–50 nm precision). In general, the normalized error was reduced at larger actuation distances and in coarse mode. These results may be used to define optimum operating conditions for piezoelectrically actuated nanomanipulators and micromanipulators whereby the goal is to find a balance between speed and accuracy. The results also are intended to allow for optimal control in closed-loop operation and for task-oriented and pick-and-place operations.

Comparative Study of the Loads Acting on the Operating Cardanic Transmission in the Closed and Open Loop Configurations

2015 ◽  
Vol 744-746 ◽  
pp. 17-24
Author(s):  
Eugen Avrigean
Keyword(s):  
Finite Elements ◽  
Comparative Study ◽  
Closed Loop ◽  
Open Loop ◽  
Operating Conditions ◽  
Motor Vehicles ◽  
Normal Operating ◽  
Static Conditions

On the basis of a comparative study, this paper aims to determine the maximum loads that can occur in operating conditions on the cardanic transmission assembly of motor vehicles in the open or closed loop configurations. The research is conducted under static conditions using finite elements and shows the components with their maximum values obtained in normal operating conditions.

Analysis of open-loop and L2∕D controlled closed-loop behavior of the Cholette’s bioreactor under different operating conditions

2020 ◽  
Vol 101 ◽  
pp. 147-159
Author(s):  
J. Carrillo-Ahumada ◽  
G. Reynoso-Meza ◽  
I.I. Ruiz-López ◽  
M.A. García-Alvarado
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
Operating Conditions

scholarly journals A Dynamic Model for the Evaluation of Aircraft Engine Icing Detection and Control-Based Mitigation Strategies

2017 ◽  
Author(s):  
Donald L. Simon ◽  
Aidan W. Rinehart ◽  
Scott M. Jones
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
Operating Conditions ◽  
Mitigation Strategies ◽  
System Level ◽  
Test Facility ◽  
Closed Loop Control ◽  
Turbofan Engine ◽  
Loop Control ◽  
And Control

Aircraft flying in regions of high ice crystal concentrations are susceptible to the buildup of ice within the compression system of their gas turbine engines. This ice buildup can restrict engine airflow and cause an uncommanded loss of thrust, also known as engine rollback, which poses a potential safety hazard. The aviation community is conducting research to understand this phenomena, and to identify avoidance and mitigation strategies to address the concern. To support this research, a dynamic turbofan engine model has been created to enable the development and evaluation of engine icing detection and control-based mitigation strategies. This model captures the dynamic engine response due to high ice water ingestion and the buildup of ice blockage in the engine’s low pressure compressor. It includes a fuel control system allowing engine closed-loop control effects during engine icing events to be emulated. The model also includes bleed air valve and horsepower extraction actuators that, when modulated, change overall engine operating performance. This system-level model has been developed and compared against test data acquired from an aircraft turbofan engine undergoing engine icing studies in an altitude test facility and also against outputs from the manufacturer’s customer deck. This paper will describe the model and show results of its dynamic response under open-loop and closed-loop control operating scenarios in the presence of ice blockage buildup compared against engine test cell data. Planned follow-on use of the model for the development and evaluation of icing detection and control-based mitigation strategies will also be discussed. The intent is to combine the model and control mitigation logic with an engine icing risk calculation tool capable of predicting the risk of engine icing based on current operating conditions. Upon detection of an operating region of risk for engine icing events, the control mitigation logic will seek to change the engine’s operating point to a region of lower risk through the modulation of available control actuators while maintaining the desired engine thrust output. Follow-on work will assess the feasibility and effectiveness of such control-based mitigation strategies.

scholarly journals Integration of Process Modeling, Design, and Optimization with an Experimental Study of a Solar-Driven Humidification and Dehumidification Desalination System

Processes ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 163 ◽  
Author(s):  
Mohammed Alghamdi ◽  
Faissal Abdel-Hady ◽  
A. Mazher ◽  
Abdulrahim Alzahrani
Keyword(s):  
Closed Loop ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Circulation Rate ◽  
Feed Water ◽  
Parabolic Trough ◽  
Circulating Water ◽  
Electrical Generation ◽  
The Impact ◽  
Promising Source

Solar energy is becoming a promising source of heat and power for electrical generation and desalination plants. In this work, an integrated study of modeling, optimization, and experimental work is undertaken for a parabolic trough concentrator combined with a humidification and dehumidification desalination unit. The objective is to study the design performance and economic feasibility of a solar-driven desalination system. The design involves the circulation of a closed loop of synthetic blend motor oil in the concentrators and the desalination unit heat input section. The air circulation in the humidification and dehumidification unit operates in a closed loop, where the circulating water runs during the daytime and requires only makeup feed water to maintain the humidifier water level. Energy losses are reduced by minimizing the waste of treated streams. The process is environmentally friendly, since no significant chemical treatment is required. Design, construction, and operation are performed, and the system is analyzed at different circulating oil and air flow rates to obtain the optimum operating conditions. A case study in Saudi Arabia is carried out. The study reveals unit capability of producing 24.31 kg/day at a circulating air rate of 0.0631 kg/s and oil circulation rate of 0.0983 kg/s. The tradeoff between productivity, gain output ratio, and production cost revealed a unit cost of 12.54 US$/m3. The impact of the circulating water temperature has been tracked and shown to positively influence the process productivity. At a high productivity rate, the humidifier efficiency was found to be 69.1%, and the thermal efficiency was determined to be 82.94%. The efficiency of the parabolic trough collectors improved with the closed loop oil circulation, and the highest performance was achieved from noon until 14:00 p.m.

Control of Impact Microactuators for Precise Positioning

2005 ◽  
Vol 1 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Xiaopeng Zhao ◽  
Harry Dankowicz
Keyword(s):  
System Design ◽  
Closed Loop ◽  
Complex Dynamics ◽  
Open Loop ◽  
Operating Conditions ◽  
System Behavior ◽  
Precise Positioning ◽  
Feedback Scheme ◽  
Loop Feedback ◽  
Closed Loop Feedback

Electrically driven impact microactuators generate nanoscale displacements without large driving distances and high voltages. These systems exhibit complex dynamics because of inherent nonlinearities due to impacts, friction, and electric forces. As a result, dramatic changes in system behavior, associated with so-called grazing bifurcations, may occur during the transition between impacting and nonimpacting dynamics, including the presence of robust chaos. For successful open-loop operating conditions, the system design is limited to certain parameter regions, where desired system responses reside. The objective of this paper is to overcome this limitation to allow for a more precise displacement manipulation using impact microactuators. This is achieved through a closed-loop feedback scheme that successfully controls the system dynamics in the near-grazing region.

Computationally Efficient Whole-Engine Model of a Cummins 2007 Turbocharged Diesel Engine

2009 ◽  
Vol 132 (2) ◽  
Author(s):  
Anup M. Kulkarni ◽  
Gregory M. Shaver ◽  
Sriram S. Popuri ◽  
Tim R. Frazier ◽  
Donald W. Stanton
Keyword(s):  
Diesel Engine ◽  
Flow Rate ◽  
Closed Loop ◽  
Engine Performance ◽  
Open Loop ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Computationally Efficient ◽  
Turbocharged Diesel Engine ◽  
Engine Model

This paper describes an accurate, flexible, and computationally efficient whole engine model incorporating a multizone, quasidimension combustion submodel for a 6.7-l six-cylinder turbocharged diesel engine with cooled exhaust gas recirculation (EGR), cooled air, and multiple fuel injections. The engine performance and NOx emissions predicative capability of the model is demonstrated at 22 engine operating conditions. The only model inputs are physical engine control module “control actions,” including injection rates, injection timings, EGR valve position, and variable geometry turbocharger rack position. The model is run using both “open” and “closed” loop control strategies for air/EGR path control, in both cases achieving very good correlation with experimental data. Model outputs include in-cylinder pressure and heat release, torque, combustion timing, brake specific fuel consumption, EGR flow rate, air flow rate, exhaust and intake pressure, and NOx emissions. The model predicts engine performance and emissions with average absolute errors within 5% and 18%, respectively, of true values with “open-loop” air/EGR control, and within 5% and 11% with “closed-loop” air/EGR control. In addition, accurate prediction of the coupling of the in-cylinder combustion and emission-production processes with the boosted, cooled air/EGR gas dynamics is a key characteristic of the model.

Open-Loop Active Control of Combustion Dynamics on a Gas Turbine Engine

2004 ◽  
Author(s):  
Geo. A. Richards ◽  
Jimmy D. Thornton ◽  
Edward H. Robey ◽  
Leonell Arellano
Keyword(s):  
Gas Turbine ◽  
Active Control ◽  
Closed Loop ◽  
Experimental Tests ◽  
Gas Turbine Engine ◽  
Open Loop ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Combustion Dynamics ◽  
Turbine Engine

Combustion dynamics is a prominent problem in the design and operation of low-emission gas turbine engines. Even modest changes in fuel composition, or operating conditions can lead to damaging vibrations in a combustor that was otherwise stable. For this reason, active control has been sought to stabilize combustors that must accommodate fuel variability, new operating conditions, etc. Active control of combustion dynamics has been demonstrated in a number of laboratories, single-nozzle test combustors, and even on a fielded engine. In most of these tests, active control was implemented with closed-loop feedback between the observed pressure signal and the phase and gain of imposed fuel perturbations. In contrast, a number of recent papers have shown that open-loop fuel perturbations can disrupt the feedback between acoustics and heat release that drives the oscillation. Compared to the closed-loop case, this approach has some advantages because it may not require high-fidelity fuel actuators, and could be easier to implement. This paper reports experimental tests of open-loop fuel perturbations to control combustion dynamics in a complete gas turbine engine. Results demonstrate the technique was very successful on the test engine, and had minimal effect on pollutant emissions.

Open-Loop Active Control of Combustion Dynamics on a Gas Turbine Engine

2006 ◽  
Vol 129 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Geo. A. Richards ◽  
Jimmy D. Thornton ◽  
Edward H. Robey ◽  
Leonell Arellano
Keyword(s):  
Gas Turbine ◽  
Active Control ◽  
Closed Loop ◽  
Experimental Tests ◽  
Gas Turbine Engine ◽  
Open Loop ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Combustion Dynamics ◽  
Turbine Engine

Combustion dynamics is a prominent problem in the design and operation of low-emission gas turbine engines. Even modest changes in fuel composition or operating conditions can lead to damaging vibrations in a combustor that was otherwise stable. For this reason, active control has been sought to stabilize combustors that must accommodate fuel variability, new operating conditions, etc. Active control of combustion dynamics has been demonstrated in a number of laboratories, single-nozzle test combustors, and even on a fielded engine. In most of these tests, active control was implemented with closed-loop feedback between the observed pressure signal and the phase and gain of imposed fuel perturbations. In contrast, a number of recent papers have shown that open-loop fuel perturbations can disrupt the feedback between acoustics and heat release that drives the oscillation. Compared to the closed-loop case, this approach has some advantages because it may not require high-fidelity fuel actuators, and could be easier to implement. This paper reports experimental tests of open-loop fuel perturbations to control combustion dynamics in a complete gas turbine engine. Results demonstrate the technique was very successful on the test engine and had minimal effect on pollutant emissions.

On closed-loop equilibrium strategies for mean-field stochastic linear quadratic problems

2020 ◽  
Vol 26 ◽  
pp. 41
Author(s):  
Tianxiao Wang
Keyword(s):  
Optimal Control ◽  
Closed Loop ◽  
Optimal Control Problems ◽  
Mean Field ◽  
Open Loop ◽  
Time Inconsistency ◽  
Control Problems ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Equilibrium Strategies

This article is concerned with linear quadratic optimal control problems of mean-field stochastic differential equations (MF-SDE) with deterministic coefficients. To treat the time inconsistency of the optimal control problems, linear closed-loop equilibrium strategies are introduced and characterized by variational approach. Our developed methodology drops the delicate convergence procedures in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. When the MF-SDE reduces to SDE, our Riccati system coincides with the analogue in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. However, these two systems are in general different from each other due to the conditional mean-field terms in the MF-SDE. Eventually, the comparisons with pre-committed optimal strategies, open-loop equilibrium strategies are given in details.

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Input Voltage ◽  
Open Loop ◽  
Current Sensor ◽  
Switching Frequency ◽  
Led Driver ◽  
Advantages And Disadvantages ◽  
Led Drivers ◽  
Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

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