Experiment With Vibrational Control of a Laser Illuminated Thermochemical System

1990 ◽  
Vol 112 (1) ◽  
pp. 42-47 ◽  
Author(s):  
J. Fakhfakh ◽  
J. Bentsman
Keyword(s):  
Open Loop ◽  
Control Technique ◽  
Loop Control ◽  
Vibrational Control ◽  
Incident Laser Power ◽  
Stable Operating ◽  
Vibrational Stabilization ◽  
Potential Applicability ◽  
On Line ◽  
Operating Regimes

Vibrational control is an open-loop control technique which utilizes zero mean parametric excitations to modify the behavior of dynamical systems in a desired manner. A potential applicability of vibrational control to laser illuminated thermochemical systems has been recently demonstrated analytically by Bentsman and Hvostov (1988). This paper presents experiments with vibrational stabilization of a laser illuminated thermochemical reaction that support the previous findings. A rectangular wave oscillating incident laser power is shown experimentally to induce asymptotically stable operating regimes with averages located at initially unstable steady states as predicted by vibrational control theory. Hence, vibrational control is demonstrated to be a feasible stabilizing strategy for laser induced reactions that needs no on-line measurements and complex actuators.

Vibrational Control of a Laser Illuminated Thermochemical System

1988 ◽  
Vol 110 (2) ◽  
pp. 109-113 ◽  
Author(s):  
J. Bentsman ◽  
H. Hvostov
Keyword(s):  
Open Loop ◽  
Asymptotically Stable ◽  
Open Loop Control ◽  
Loop Control ◽  
Driven Systems ◽  
Vibrational Control ◽  
Stable Operating ◽  
Control Principle ◽  
Operating Regimes ◽  
Thermochemical Reaction

Vibrational control is a nonclassical open-loop control principle which proposes a utilization of zero mean parametric excitation of a dynamical system for achieving control objectives. In the present paper, excitations introduced into the incident power of a laser beam in a laser illuminated thermochemical reaction are shown to be capable of inducing asymptotically stable operating regimes with averages located at initially unstable steady states. This opens a possibility of alleviating measurement and actuator related difficulties associated with conventional methods in a stabilization of laser-driven systems.

A Spectral Feedback Compensation Technique for the Generation of Random Wave Fields

1994 ◽  
Vol 208 (2) ◽  
pp. 105-112 ◽  
Author(s):  
V Rouillard ◽  
G T Lleonart
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
Control Technique ◽  
Random Wave ◽  
Closed Loop Control ◽  
Random Waves ◽  
Wave Fields ◽  
Loop Control ◽  
Spectral Models ◽  
Spectral Feedback

Computer software was developed to control an electromechanical wave generator to accurately simulate random wave fields derived from mathematical spectral models. The software algorithm makes use of a spectral feedback control technique to improve accuracy and reliability in the continuous generation of random waves in the laboratory. Experiments were conducted to investigate the advantages of this closed-loop control technique over more commonly used open-loop random wave generation methods. The results show a decided advantage in using closed-loop control for the generation of random waves, especially for double-peak wave spectra and model testing purposes.

scholarly journals Open Loop Execution of Tree-Search Algorithms

2018 ◽  
Author(s):  
Erwan Lecarpentier ◽  
Guillaume Infantes ◽  
Charles Lesire ◽  
Emmanuel Rachelson
Keyword(s):  
Search Algorithms ◽  
Open Loop ◽  
Tree Search ◽  
Open Loop Control ◽  
Time Step ◽  
Line Planning ◽  
Loop Control ◽  
Stochastic Planning ◽  
On Line ◽  
Planning Algorithms

In the context of tree-search stochastic planning algorithms where a generative model is available, we consider on-line planning algorithms building trees in order to recommend an action. We investigate the question of avoiding re-planning in subsequent decision steps by directly using sub-trees as action recommender. Firstly, we propose a method for open loop control via a new algorithm taking the decision of re-planning or not at each time step based on an analysis of the statistics of the sub-tree. Secondly, we show that the probability of selecting a suboptimal action at any depth of the tree can be upper bounded and converges towards zero. Moreover, this upper bound decays in a logarithmic way between subsequent depths. This leads to a distinction between node-wise optimality and state-wise optimality. Finally, we empirically demonstrate that our method achieves a compromise between loss of performance and computational gain.

A New Induction Motor Adaptive Robust Vector Control based on Backstepping

2017 ◽  
Vol 7 (4) ◽  
pp. 1983 ◽  
Author(s):  
Mhamed Madark ◽  
A. Ba-Razzouk ◽  
E. Abdelmounim ◽  
M.El Malah
Keyword(s):  
Vector Control ◽  
Time Constant ◽  
Induction Machine ◽  
Open Loop ◽  
Control Technique ◽  
Load Torque ◽  
Novel Approach ◽  
Rotor Flux ◽  
On Line ◽  
Simulation Results

<p>In this paper, a novel approach to nonlinear control of induction machine, recursive on-line estimation of rotor time constant and load torque are developed. The proposed strategy combines Integrated Backstepping and Indirect Field Oriented Controls. The proposed approach is used to design controllers for the rotor flux and speed, estimate the values of rotor time constant and load torque and track their changes on-line. An open loop estimator is used to estimate the rotor flux. Simulation results are presented which demonstrate the effectiveness of the control technique and on-line estimation.</p>

scholarly journals A dual-loop tracking control approach to precise nanopositioning

2018 ◽  
Vol 25 (3) ◽  
pp. 666-674 ◽  
Author(s):  
Mohammed Altaher ◽  
Douglas Russell ◽  
Sumeet S. Aphale
Keyword(s):  
Closed Loop ◽  
Reference Signal ◽  
Open Loop ◽  
Performance Criteria ◽  
Control Technique ◽  
Loop Control ◽  
Control Approach ◽  
First Order ◽  
Integral Controller ◽  
Double Integrator

Nanopositioners are mechanical devices that can accurately move with a resolution in the nanometer scale. Due to their mechanical construction and the piezoelectric actuators popularly employed in nanopositioners, these devices have severe performance limitations due to resonance, hysteresis and creep. A number of techniques to control nanopositioners, both in open-loop and closed-loop, have been reported in the literature. Closed-loop techniques clearly outperform open-loop techniques due to several desirable characteristics, such as robustness, high-bandwidth, absence of the need for tuning and high stability, along with others. The most popular closed-loop control technique reported is one where a damping controller is first employed in an inner loop to damp the mechanical resonance of the nanopositioner, thereby increasing achievable bandwidth. Consequently, a tracking controller, typically an Integral controller or a proportional–integral controller, is implemented in the outer loop to enforce tracking of the reference signal, thereby reducing the positioning errors due to hysteresis and creep dynamics of the employed actuator. The most popular trajectory a nanopositioner is forced to track is a raster scan, which is generated by making one axis of the nanopositioner follow a triangular trajectory and the other follow a slow ramp or staircase. It is quite clear that a triangle wave (a finite velocity, zero acceleration signal) cannot be perfectly tracked by a first-order integrator and a double integrator is necessary to deliver error-free tracking. However, due to the phase profile of the damped closed-loop system, implementing a double integrator is difficult. This paper proposes a method by which to implement two integrators focused on the tracking performance. Criteria for gain selection, stability analysis, error analysis, simulations, and experimental results are provided. These demonstrate a reduction in positioning error by 50%, when compared to the traditional damping plus first-order integral tracking approach.

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