Active Combustion Instability Control With Spinning Valve Actuator

2003 ◽  
Vol 125 (4) ◽  
pp. 925-932 ◽  
Author(s):  
P. Barooah ◽  
T. J. Anderson ◽  
J. M. Cohen
Keyword(s):  
Real World ◽  
Closed Loop ◽  
Open Loop ◽  
Control Input ◽  
Engine Fuel ◽  
Low Frequencies ◽  
Flow Modulation ◽  
Flow Control Devices ◽  
Instability Control ◽  
Set Up

Active combustion control has been accomplished in many laboratory and real-world combustion systems by fuel modulation as the control input. The modulation is commonly achieved using reciprocating flow control devices. These demonstrations have been successful because the instabilities have been at relatively low frequencies (∼200 Hz) or the scale of demonstration has been small enough to require very small levels of modulation. A number of real-world instabilities in gas turbine engines involve higher frequencies (200–500 Hz) and attenuation requires the modulation of large fractions of the engine fuel flow rate (hundreds of pounds per hour). A spinning drum valve was built to modulate fuel for these applications. Tests showed that this device provided more than 30% flow modulation up to 800 Hz for liquid fuel flows of greater than 400 lbm/hr. This paper describes the performance of the valve in flow bench tests, open-loop forcing, and closed-loop instability control tests. The closed-loop tests were done on a single-nozzle combustor rig which exhibited a limit-cycling instability at a frequency of ∼280 Hz with an amplitude of ∼7 psi. It also encounters an instability at 575 Hz under a different set up of the rig, though active control on that instability has not been investigated so far. The test results show that the spinning valve could be effectively used for active instability control, though the control algorithms need to be developed which will deal with or account for actuator phase drift/error.

Active Combustion Instability Control With Spinning Valve Actuator

2002 ◽  
Author(s):  
Prabir Barooah ◽  
Torger J. Anderson ◽  
Jeffrey M. Cohen
Keyword(s):  
Real World ◽  
Closed Loop ◽  
Open Loop ◽  
Control Input ◽  
Engine Fuel ◽  
Low Frequencies ◽  
Flow Modulation ◽  
Flow Control Devices ◽  
Instability Control ◽  
Set Up

Active combustion control has been accomplished in many laboratory and real-world combustion systems by fuel modulation as the control input. The modulation is commonly achieved using reciprocating flow control devices. These demonstrations have been successful because the instabilities have been at relatively low frequencies (∼200 Hz) or the scale of demonstration has been small enough to require very small levels of modulation. A number of real-world instabilities in gas turbine engines involve higher frequencies (200–500 Hz) and attenuation requires the modulation of large fractions of the engine fuel flow rate (hundreds of pounds per hour). A spinning drum valve was built to modulate fuel for these applications. Tests showed that this device provided more than 30% flow modulation up to 800 Hz for liquid fuel flows of greater than 400 lbm/hr. This paper describes the performance of the valve in flow bench tests, open-loop forcing and closed-loop instability control tests. The closed loop tests were done on a single-nozzle combustor rig which exhibited a limit-cycling instability at a frequency of ∼280 Hz with an amplitude of ∼7 psi. It also encounters an instability at 575 Hz under a different set up of the rig, though active control on that instability has not been investigated so far. The test results show that the spinning valve could be effectively used for active instability control, though the control algorithms need to be developed which will deal with or account for actuator phase drift/error.

An L1 adaptive closed-loop guidance law for an orbital injection problem

2009 ◽  
Vol 223 (6) ◽  
pp. 753-761 ◽  
Author(s):  
J Roshanian ◽  
M Zareh ◽  
H H Afshari ◽  
M Rezaei
Keyword(s):  
Closed Loop ◽  
Adaptive Strategy ◽  
Analytical Form ◽  
Open Loop ◽  
Control Input ◽  
Guidance Law ◽  
Non Linear ◽  
Non Linear System ◽  
Orbital Injection

The current paper presents the determination of a closed-loop guidance law for an orbital injection problem using two different approaches and, considering the existing time-optimal open-loop trajectory as the nominal solution, compares the advantages of the two proposed strategies. In the first method, named neighbouring optimal control (NOC), the perturbation feedback method is utilized to determine the closed-loop trajectory in an analytical form for the non-linear system. This law, which produces feedback gains, is in general a function of small perturbations appearing in the states and constraints separately. The second method uses an L1 adaptive strategy in determination of the non-linear closed-loop guidance law. The main advantages of this method include characteristics such as improvement of asymptotic tracking, guaranteed time-delay margin, and smooth control input. The accuracy of the two methods is compared by introducing a high-frequency sinusoidal noise. The simulation results indicate that the L1 adaptive strategy has a better performance than the NOC method to track the nominal trajectory when the noise amplitude is increased. On the other hand, the main advantage of the NOC method is its ability to solve a non-linear, two-point, boundary-value problem in the minimum time.

Dynamic Emulation Using an Indirect Control Input

2004 ◽  
Vol 127 (1) ◽  
pp. 114-124 ◽  
Author(s):  
Rong Zhang ◽  
Andrew G. Alleyne
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
Control Input ◽  
Available Bandwidth ◽  
High Frequency Response ◽  
Physical Plant ◽  
Generalized Framework ◽  
Dynamic Emulation ◽  
Primary Focus ◽  
Output Only

This paper presents a generalized framework to analyze and design controllers for a class of dynamic emulation systems. This class of systems features some structurally distinctive control frameworks which inherently limit the available bandwidth for dynamic emulation. The primary focus is on control structures that we define as indirect. This means the signal from the controller does not affect the physical plant directly; it interacts in combination with other exogenous signals to affect a behavior on the physical system interacting with the emulated load. It is shown that the achievable closed-loop performance is limited in a unique way: the high-frequency response of the controlled closed-loop system converges to the dynamics of the open-loop physical plant that is interacting with the emulated load. This paper illustrates the three controller configurations of the indirect emulation and gives guidelines on how to improve the performance within the identified structural limitations. The three configurations are: a feedback design measuring plant output only, a feedforward design measuring an exogenous signal, and a two degree-of-freedom design combining feedback and feedforward measurements. A detailed analysis in the frequency domain is used to support the experimental results illustrated on a Hardware-in-the-Loop (HIL) system. The demonstration case is a high-bandwidth transient dynamometer to emulate rapidly varying loads associated with an earthmoving vehicle powertrain.

scholarly journals Implicit Euler Implementation of Twisting Controller and Super-Twisting Observer without Numerical Chattering: Precise Quasi-Static MEMS Mirrors Control

2019 ◽  
Vol 256 ◽  
pp. 03004 ◽  
Author(s):  
Dong Luo ◽  
Xiaogang Xiong ◽  
Shanhai Jin ◽  
Wei Chen
Keyword(s):  
Sliding Mode Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Industrial Applications ◽  
Euler Method ◽  
Open Loop ◽  
Closed Loop Control ◽  
Control Input ◽  
Loop Control ◽  
Mode Control

The quasi-static operations of MEMS mirror are very sensitive to undesired oscillations due to its very low damping. It has been shown that closed-loop control can be superior to reduce those oscillations than open-loop control in the literature. For the closed-loop control, the conventional way of implementing sliding mode control (SMC) algorithm is forward Euler method, which results in numerical chattering in the control input and output. This paper proposes an implicit Euler implementation scheme of super twisting observer and twisting control for a commercial MEMS mirror actuated by an electrostatic staggered vertical comb (SVC) drive structure. The famous super-twisting algorithm is used as an observer and twisting SMC is used as a controller. Both are discretized by an implicit Euler integration method, and their implementation algorithms are provided. Simulations verify that, as compared to traditional sliding mode control implementation, the proposed scheme reduces the chattering both in trajectory tracking output and control input in presence of model uncertainties and external disturbances. The comparison demonstrates the potential applications of the proposed scheme in industrial applications in terms of feasibility and performance.

A New Close-Loop Control Method for an Inspection Robot Equipped with Electropermanent-Magnets

2016 ◽  
Vol 28 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Pakpoom Kriengkomol ◽  
◽  
Kazuto Kamiyama ◽  
Masaru Kojima ◽  
Mitsuhiro Horade ◽  
...  
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Steel Structures ◽  
Open Loop ◽  
Closed Loop Control ◽  
Loop Control ◽  
Inspection Robot ◽  
Industrial Age ◽  
Set Up ◽  
Close Loop Control

[abstFig src='/00280002/09.jpg' width=""300"" text='ASTERISK use our proposed method to walk' ]Since the industrial age began, increasing numbers of manufacturing plants have been set up to serve economic growth demand. More bridges were built simultaneously to connect cities and to make transportation more convenient. As these facilities have aged, regular maintenance has increased. The limb mechanism project we started almost 20 years ago was to deliver new types of inspection and maintenance to industrial fields. Our first prototype, a six-limb robot called Asterisk, included such capabilities as walking on ceilings, climbing and descending stairs and ladders, walking tightropes, and transversing rough terrain. Asterisk's latest version uses electromagnets to work in antigravity environments such as steel structures. Unfortunately, this presented a major danger, requiring that we replace electromagnets with electropermanent magnets (EPMs). Limitations on EPMs, however, required a new control strategy. We propose and compare three control methods -- open-loop control, closed-loop control using torque feedback, and closed-loop control using angle feedback -- in the sections that follow. Our objective is to determine the best control for inspection robots having electropermanent magnets but not using additional sensors.

Accounting for Out-of-Bandwidth Modes in the Assumed Modes Approach: Implications on Colocated Output Feedback Control

1997 ◽  
Vol 119 (3) ◽  
pp. 390-395 ◽  
Author(s):  
R. L. Clark
Keyword(s):  
Output Feedback ◽  
Closed Loop ◽  
Output Feedback Control ◽  
Open Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Open Loop System ◽  
Low Frequencies ◽  
Poles And Zeros ◽  
Admissible Functions

Colocated, output feedback is commonly used in the control of reverberant systems. More often than not, the system to be controlled displays high modal density at a moderate frequency, and thus the compliance of the out-of-bandwidth modes significantly influences the performance of the closed-loop system at low frequencies. In the assumed modes approach, the inclusion principle is used to demonstrate that the poles of the dynamic system converge from above when additional admissible functions are used to expand the solution. However, one can also interpret the convergence of the poles in terms of the zeros of the open-loop system. Since colocated inputs and outputs are known to have interlaced poles and zeros, the effect of a modification to the structural impedance locally serves to couple the modes of the system through feedback. The poles of the modified system follow loci defined by the relative location of the open-loop poles and zeros. Thus, as the number of admissible functions used in the series expansion is increased, the interlaced zeros of the colocated plant tend toward the open-loop poles, causing the closed-loop poles to converge from above as predicted by the inclusion principle. The analysis and results presented in this work indicate that the cumulative compliance of the out-of-bandwidth modes and not the modes themselves is required to converge the zeros of the open-loop system and the poles of the closed-loop system.

Adaptive control designs for control-based continuation in a class of uncertain discrete-time dynamical systems

2020 ◽  
Vol 26 (21-22) ◽  
pp. 2092-2109
Author(s):  
Yang Li ◽  
Harry Dankowicz
Keyword(s):  
Adaptive Control ◽  
Discrete Time ◽  
Closed Loop ◽  
Control Strategies ◽  
Open Loop ◽  
Numerical Continuation ◽  
Pole Placement ◽  
Control Input ◽  
Loop Dynamics ◽  
Reference Input

This article proposes a methodology for integrating adaptive control with the control-based continuation paradigm for a class of uncertain, linear, discrete-time systems. The proposed adaptive control strategies aim to stabilize the closed-loop dynamics with convergence toward a known reference input, such that the dynamics approach the open-loop fixed point if the reference input is chosen to make the steady-state control input equal 0. This enables the tracking of a parameterized branch of open-loop fixed points using methods of numerical continuation without specific knowledge about the system. We implement two different adaptive control strategies: model-reference adaptive control and pole-placement adaptive control. Both implementations achieve the desired objectives for the closed-loop dynamics and support parameter continuation. These properties, as well as the boundedness of system states and control inputs, are guaranteed provided that certain stability conditions are satisfied. Besides, the tuning effort is significantly reduced in the adaptive control schemes compared with traditional proportional–derivative controllers and linear state-space feedback controllers.

Prediction of Dynamic Behavior of a Single Shaft Gas Turbine Using NARX Models

2021 ◽  
Author(s):  
Hamid Asgari ◽  
Emmanuel Ory
Keyword(s):  
Gas Turbine ◽  
Dynamic Behavior ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Closed Loop ◽  
Open Loop ◽  
Loop Model ◽  
Narx Models ◽  
Set Up ◽  
Matlab Programming

Abstract Gas turbines are internal combustion engines widely used in industry as main source of power for aircrafts, turbo-generators, turbo-pumps and turbo-compressors. Modelling these engines can help to improve their design and manufacturing processes, as well as to facilitate their operability and maintenance. These eventually lead to manufacturing of gas turbines with lower costs and higher efficiency at the same time. The models may also be employed to unfold nonlinear dynamics of these systems. The aim of this study is to predict the dynamic behavior of a single shaft gas turbine by using open-loop and closed-loop NARX models, which are subsets of artificial neural networks. To set up these models, datasets of significant variables of the gas turbine are used for training, test and validation processes. For this purpose, a comprehensive code is developed in MATLAB programming environment. In addition to the open-loop model, a closed-loop model is set up for multi-step prediction. The results of this study demonstrate the capability of the NARX models in reliable prediction of gas turbines’ dynamic behaviors over different operational ranges.

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.

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