Finite Transient Time Research Articles

Distributed Finite-Time Consensus Control of Multiagent Systems With Fully Intermittent Communication via Dynamic Event-Triggered Strategy

Taking into account the multi-agent systems (MASs) with the single-order integrator dynamics and the directed internal topology, this brief is devoted to investigating the finite-time consensus (FTC) control problem based on the event-triggered strategy (ETS). A novel dynamic and state-dependent ETS is designed by using an adaptive and dynamic variable for each agent. Based on the triggered states, a discontinuous FTC control strategy is proposed and the tools from the non-smooth analysis theory are adapted to analyze the stability. Moreover, under the developed protocol, consensus can be realized after a finite transient time while avoiding the continuous information transmissions among agents. Finally, the effectiveness corroboration of the theoretical results are provided by the numerical simulation.

Finite-Time State Observer for a Class of Linear Time-Varying Systems With Unknown Inputs

A finite-time observer for a class of linear time-varying systems with bounded unknown inputs is presented in this note. The design of the observer exploits structural properties of the system and, through a linear operator, allows applying the robust exact differentiator in a block form without requiring additional stabilizing terms. The proposed observer provides an exact estimate of the states after a finite transient time despite the possible instability of the system and the effects of bounded unknown inputs.

Robust Trajectory Tracking for an Uncertain UAV Based on Active Disturbance Rejection

This note addresses the design of a robust trajectory tracking controller based on active disturbance rejection for a quadrotor Unmanned Aircraft Vehicle (UAV). A standard state-feedback linearizing controller, designed using a nominal model, is applied for tracking reference signals. An active disturbance rejection technique based on high-order sliding modes compensates for the uncertainties and nonlinearities. Furthermore, this rejection technique provides robustness against uncertainties and external disturbances after a finite transient time. Outdoors experimental results in a prototype illustrate the workability of the proposed methodology.

Output Control of Nonlinear Systems Using Modified Backstepping Algorithm with Disturbances Compensation

The article deals with a tracking control system synthesis for a nonlinear plant functioning under bounded external disturbances which are not available for measurement. A proposed solution is a robust modification of the backstepping approach with the similar controller design structure. The main changes are based on plant model transformations that make it possible to use the only one filer in control system and, along with it, an auxiliary loop method usage to disturbances evaluation and compensation. High-gain observers are used for unknown signals measuring together with their derivatives. Tracking errors and observation errors convergence with the adjustable accuracy during the finite transient time is proved. Efficiency of the algorithm is demonstrated using computer modeling in comparison with an analogue.

Finite-Time Consensus With Disturbance Rejection by Discontinuous Local Interactions in Directed Graphs

In this technical note we propose a decentralized discontinuous interaction rule which allows to achieve consensus in a network of agents modeled by continuous-time first-order integrator dynamics affected by bounded disturbances. The topology of the network is described by a directed graph. The proposed discontinuous interaction rule is capable of rejecting the effects of the disturbances and achieving consensus after a finite transient time. An upper bound to the convergence time is explicitly derived in the technical note. Simulation results, referring to a network of coupled Kuramoto-like oscillators, are illustrated to corroborate the theoretical analysis.

Finite-time consensus for switching network topologies with disturbances

In this paper we investigate the properties of a decentralized consensus algorithm for a network of continuous-time integrators subject to unknown-but-bounded time-varying disturbances. The proposed consensus algorithm is based on a discontinuous local interaction rule. Under certain restrictions on the switching topology, it is proven that after a finite transient time the agents achieve an approximated consensus condition by attenuating the destabilizing effect of the disturbances. This main result is complemented by an additional result establishing the achievement of consensus under different requirements on the switching communication topology. In particular, we provide a convergence result that encompasses situations in which the time varying graph is always disconnected. Lyapunov analyses are carried out to support the suggested algorithms and results. Simulative tests considering, as case study, the synchronization problem for a network of clocks are illustrated and commented on to validate the developed analysis.

Finite-Time Consensus based Clock Synchronization by Discontinuous Control

In this paper we develop a decentralized discontinuous algorithm which guarantees the finite time synchronization of a network of clocks, which are modeled as continuous-time integrators and are subject to unknown-but-bounded time-varying disturbances. The proposed synchronization algorithm is asynchronous and consists in a randomly applied local interaction rule. After a finite transient time, the proposed algorithm provides the approximated synchronization of the network by attenuating the destabilizing effect of the disturbances. Lyapunov analysis is carried out to substantiate the suggested algorithm, and simulation results are illustrated throughout the paper.

Model of lock-in in a ring laser and a semiconductor laser gyro

It is assumed that the process of lock-in in a ring laser has a finite transient time. This assumption serves as a basis for developing a semiconductor laser gyro. A semiconductor optical amplifier is applied as an amplifying medium, and a ring resonator represents a long optical fiber. The injection of an external single-frequency light into a ring resonator with subsequent circulation of counterpropagating waves is used. The light characteristics of the semiconductor laser gyro are discussed, and the rotation sensitivity of the gyro is demonstrated.

Max algebraic powers of irreducible matrices in the periodic regime: An application of cyclic classes

In max algebra it is well known that the sequence of max algebraic powers A k , with A an irreducible square matrix, becomes periodic after a finite transient time T ( A ) , and the ultimate period γ is equal to the cyclicity of the critical graph of A . In this connection, we study computational complexity of the following problems: (1) for a given k , compute a periodic power A r with r ≡ k ( mod γ ) and r ⩾ T ( A ) , (2) for a given x , find the ultimate period of { A l ⊗ x } . We show that both problems can be solved by matrix squaring in O ( n 3 log n ) operations. The main idea is to apply an appropriate diagonal similarity scaling A ↦ X - 1 AX , called visualization scaling, and to study the role of cyclic classes of the critical graph.

Transient response during resistance switching in Ag∕Pr0.7Ca0.3MnO3∕Pt thin films

The transient response during resistance switching in Ag∕Pr0.7Ca0.3MnO3∕Pt thin films is investigated by measurements using pulsed voltage biases. Semiconducting Pr0.7Ca0.3MnO3 (PCMO) films sandwiched by Ag and Pt electrodes show nonvolatile resistance switching (two orders of magnitude) as a result of applying pulsed voltage biases, even at room temperature. The transient responses of the voltage across the PCMO for a set (positive) and a reset (negative) pulse application are consistent with the resistance-switching behavior and show quite fast switching (3–100 ns) for the set pulse application, compared with 60–135 ns for the reset pulse application. The large resistance-switching ratio is saturated after a finite transient time, indicating that the carrier filling of the trap sites into PCMO is completed within quite a short time.

Pseudo hysteresis current loop and negative differential resistance in cluster superlattice of tellurium in zeolite

We study electron transport properties of tellurium (Te) cluster superlattice in Linde type-A zeolite. Applying a constant voltage, current–voltage ( I– V) curve shows a hysteresis loop with a pseudo negative differential resistance (PNDA). The current loop and the current peak are history dependent. Under the same experimental conditions, we find that the current peak position moves to a higher voltage when the sample temperature is increased. Applying a variable voltage, I– V curve can be both monotonic and non-monotonic, depending on the frequency of the source. If a biased source is applied on the sample, the I– V curve will change with time, and eventually reach a stable state at which the current is a monotonical function of voltage. We clarify that both the current loop and peak are transient phenomena. The main transport mechanism is identified as non-resonant electron tunneling. The observed I– V characteristics can be attributed to the structure change of Te clusters inside the zeolite cages under an external electric field. The current peak can be understood as the effect of the finite transient time during which the Te cluster structure changes from one to another under an applied voltage. The temperature dependence of the peak position can be well described by many small collision assumption. With a simple mean-field-type approximation, the peak position is found to be proportional to the square root of the temperature.

Nonresonant electron tunneling in cluster superlattice of tellurium in zeolite

We study the current-voltage (I–V) characteristics of tellurium (Te) cluster superlattice in Linde type-A (LTA) zeolite. We observed both the hysteresis current loop and the current peak. The current loop and the current peak, however, are history dependent. Under the same experimental conditions, we find that the current peak position moves to the higher voltage when the sample temperature is increased. We clarify that both the current loop and peak are transient phenomena. The observed current peak is a phenomenon of the pseudonegative differential resistance. We explain the observed I–V characteristics as the results of the structure change of Te clusters inside zeolite cages under an external electric field. The current peak can be understood as the effect of the finite transient time during which Te clusters change from one structure into another under an applied voltage.

Time Domain Analyses for Various Types of Dielectric Relaxations by a Lumped Capacitor Method

Several formulas are proposed for analyzing by a lumped capacitor method time domain responses to an incident wave of finite transient time for different types of dielectric relaxations with dc electric conductivities. The experimental problems associated with the transient behavior of the responses and the measurements of the multiple relaxation type dielectric relaxations are discussed.