1,723,679 research outputs found
Bounded positive adaptive control for counterflow heat exchangers
Get PDF"In this work, we propose an outlet temperature control scheme for counterflow heat exchangers, that takes into account and actually exploits the analytical-stability features inherent to the open-loop dynamics. As a result, outlet temperature regulation is achieved through a simple adaptive controller which does not need to feedback the whole state vector and does not depend on the exact value of the system parameters. Furthermore, positivity and boundedness (nonsaturation) of the input flow rate are additionally guaranteed through the proposed approach, without entailing complex control algorithms or stability proofs. The analytical developments are corroborated through experimental results.
Robust global stabilizing bounded control of a PVTOL aircraft with lateral coupling
Get PDF"This note provides a detailed stability analysis of a global stabilizing control algorithm for a PVTOL aircraft with lateral coupling (è ≠ 0) and bounded inputs. Such control approach was originally proposed considering è ≠ 0. The analysis furnished here proves the robustness of the original scheme with respect to the existence of lateral coupling. The presented methodology is based on the use of embedded saturation functions and a result of global asymptotic stabilization for cascade systems.
Speed-gradient adaptive high-gain observers for synchronization of chaotic systems
Get PDF"We address the problem of output feedback synchronization of certain chaotic systems, under parameter uncertainty. That is, given a master system, the objective is to design a slave system that copies the dynamics of the master and reconstructs both the state and the values of the constant parameters of the master system. Hence, the synchronization problem that we address enters in the framework of Pecora and Carroll and relies on adaptive observer theory. In particular, the conditions that we impose take the form of persistency of excitation.
Stabilization of 2-D Linear Parameter-Varying Systems using Parameter-Dependent Lyapunov Function: An LMI Approach
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Evaluation of the symmetrically-switched converter structures on the frequency regulation of standalone micro hydro power plants
Get PDFMicro hydro power plants (¿HPP) are typically used to supply electric energy to microgrids outside the national power grids taking care of the frequency control of the isolated system. A conventional way to maintain the load balance in the system is to use thyristor switched AC-AC converters controlled dump loads. A disadvantage of the AC-AC converters is their reactive power consumption decreasing the power factor at the generator output. To avoid this problem the authors have earlier proposed two converter topologies utilizing symmetrical switching scheme resulting to zero reactive power consumption. The objective of this paper is to evaluate the frequency regulation loop performance of the dump load controlled single generator system by using the symmetrically switched converter structures. Evaluation is carried out by analyzing the performances of different converter structures in a simulator representing the operation of a Cuban ¿HPP “Los Gallegos”. The results showed that the frequency regulation loop performance using each proposed converter structure satisfied the Cuban standard of frequency regulation, but with the symmetrically switched structures reactive power consumption was reduced resulting to reduced losses and improved effective current delivery capacity of the generator.Postprint (published version
Evaluation of the symmetrically-switched converter structures on the frequency regulation of standalone micro hydro power plants
Get PDFMicro hydro power plants (¿HPP) are typically used to supply electric energy to microgrids outside the national power grids taking care of the frequency control of the isolated system. A conventional way to maintain the load balance in the system is to use thyristor switched AC-AC converters controlled dump loads. A disadvantage of the AC-AC converters is their reactive power consumption decreasing the power factor at the generator output. To avoid this problem the authors have earlier proposed two converter topologies utilizing symmetrical switching scheme resulting to zero reactive power consumption. The objective of this paper is to evaluate the frequency regulation loop performance of the dump load controlled single generator system by using the symmetrically switched converter structures. Evaluation is carried out by analyzing the performances of different converter structures in a simulator representing the operation of a Cuban ¿HPP “Los Gallegos”. The results showed that the frequency regulation loop performance using each proposed converter structure satisfied the Cuban standard of frequency regulation, but with the symmetrically switched structures reactive power consumption was reduced resulting to reduced losses and improved effective current delivery capacity of the generator.Postprint (published version
Dynamics of generic linear agents over signed networks without structural constraints
No full textSigned networks have been widely used to describe cooperative and competitive interactions in multiagent systems (MASs) so far. Most of the existing dynamics results of MASs on signed networks have a certain constraint on the network topology, that is, the network topology is required to have sufficient connectivity for realizing consensus or bipartite consensus. The highlight of this article is to extend the existing dynamics of MASs to a more general signed network, in which there are no any structural constraints on the topology. This general setting of the network topology unifies most existing models, such as consensus, bipartite consensus, and bipartite containment, which are usually analyzed separately in the same framework using different methods. Relying on a method of constructing cooperative auxiliary digraphs, it is theoretically proved that the agents in closed strong connected components with balanced structure and unbalanced structure gradually reach separately bipartite consensus and consensus, and the agents outside the closed strong connected components gradually enter the convex hull formed by the agents in the closed strong connected components, that is, achieving bipartite containment. Finally, a computer simulation is presented to verify the theoretical discovery
Reinforcement learning based anti-jamming schedule in cyber-physical systems
Get PDFIn this paper, the security issue of cyber-physical systems is investigated, where the observation data is transmitted from a sensor to an estimator through wireless channels disturbed by an attacker. The failure of this data transmission occurs, when the sensor accesses the channel that happens to be attacked by the jammer. Since the system performance measured by the estimation error depends on whether the data transmission is a success, the problem of selecting the channel to alleviate the attack effect is studied. Moreover, the state of each channel is time-variant due to various factors, such as path loss and shadowing. Motivated by energy conservation, the problem of selecting the channel with the best state is also considered. With the help of cognitive radio technique, the sensor has the ability of selecting a sequence of channels dynamically. Based on this, the problem of selecting the channel is resolved by means of reinforcement learning to jointly avoid the attack and enjoy the channel with the best state. A corresponding algorithm is presented to obtain the sequence of channels for the sensor, and its effectiveness is proved analytically. Numerical simulations further verify the derived results
Intelligent tuning and adaptive control selected papers from the IFAC Symposium, Singapore, 15-17 January 1991
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