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A family of linear time-varying systems with an input, an output and delays in the input is considered. It is shown that, under a stabilizability and a detectability assumption, systems of this family can be exponentially stabilized through a time-varying feedback depending on past values of the output and the input.
This paper discusses the problem of impact time control of an interceptor against a stationary target. A nonlinear guidance law is proposed with the interceptor heading angle variation as a function of the range to target. Closed-form expressions for the design parameters are derived for an exact analysis of the impact time. A feedback form of the guidance law is presented for addressing realistic...
Monotone systems comprise an important class of dynamical systems that are of interest both for their wide applicability and because of their interesting mathematical properties. It is known that under the property of quasimono-tonicity time-delayed systems become monotone, and some remarkable properties have been reported for such systems. These include, for example, the fact that for linear systems...
A decentralized controller is presented along with sufficient conditions for stability in leader-based synchronization of communication-delayed networked agents. The agents have heterogeneous dynamics modeled by uncertain, nonlinear Euler-Lagrange equations of motion affected by heterogeneous, unknown, exogenous disturbances. The developed controller requires only one-hop (delayed) communication from...
Recently, the data size of digital content has increased. To address the resultant storage issues, manufacturers have tried to increase storage capacity by narrowing the track pitch of digital storage media.[1] Considering all these factors, a high-precision tracking control system is required for optical discs. In this study, this paper develop and implement a feedforward control system using an...
An implementation strategy for closed-loop stability of nonlinear systems under real-time Lyapunov-based economic model predictive control (LEMPC) with potentially unknown and time-varying delay is considered. To address closed-loop stability (in the sense of boundedness of the closed-loop state in a compact state-space set), the strategy features a triggered evaluation of the LEMPC optimization problem...
This paper investigates the problem of load frequency control (LFC) for power systems with large delay periods (LDPs), which is often present in practical power systems and makes them unstable. LFC for power systems with LDPs has been modeled as switched delay systems, which include an unstable subsystem caused by LDPs. The switching strategy is used to deal with the stability problem of LFC for power...
In this paper we address a control problem for an autonomous tethered kite system for the purpose of airborne wind energy generation. In particular, we design a tracking controller for the velocity vector orientation of the kite. Motivated by empirical data we model the kite steering behaviour as a delayed dynamical system and explicitly utilise the derived model information for the controller design...
Some Inherent Vehicular Ad Hoc Networks (VANETs) characteristics, such as intermittent connectivity, highly dynamic topology, and hard delay constraints, make data communication a challenging task in these networks. Due to such peculiarities, in this work we study the impact of using vehicles predicted locations as a metric for data communication in VANETs. In our proposal, called LPRV (Localization...
A monocular vision-based approach to indoor autonomous navigation for an off-the-shelf, low-cost Micro Air Vehicle (MAV) quadcopter is presented. Our approach is fully automated and relies on the extraction and analysis of the visual contours of the surrounding physical environment to successfully steer the MAV in hallways and to turn at intersections. All image analysis and processing necessary for...
As special applications of delay tolerant networks (DTNs), efficient data collection and event detection in the deep sea pose some unique challenges, due to the need of timely data reporting and the delay of acoustic transmission in the ocean. Since underwater communications suffer from a significant signal attenuation, autonomous underwater vehicles (AUVs) deployed in the deep sea are used to surface...
This paper presents a novel quadrotor UAV attitude control algorithm to realize complex acrobatic UAV maneuvers. A nonlinear dynamic model based on the exponential coordinates parametrization of rotation is proposed. By analysing the model using Lie Group and Lie Algebra theory, cascaded linear PID controllers are designed. To further improve the controller performance, PID controllers are augmented...
This paper considers the position tracking control problem of uncertain flexible joint robot system with input time-delay. A new approach is proposed by using prediction scheme and dynamic surface control method. All the signals of the considered system are guaranteed semi-globally uniformly ultimately bounded. Moreover, the tracking error can be tuned as small as possible. A simulation example is...
This paper focusses on the strange nature and qualitative behavior associated with the systems characterized by State Dependent-Delay Differential Equations (SD-DDEs). We consider one of the most simple and innocently looking SD-DDEs x(t) = ±x(t-x(t)). This retarded SD-DDE brings a lot of intricacies. It looks linear but is actually a nonlinear SD-DDE in disguise. It exhibits the phenomenon of bifurcation...
Tracking an angular position trajectory of a mass attached to the free end of a motor shaft with large torsional flexibility is considered. The dynamical model of this plant is an example of a nonlinear system which does not admit a retarded state representation, but only a so-called neutral one. It is a connection of a nonlinear system without delays, the PM stepper motor, and a linear delay system,...
In this paper it is proposed a solution to the regulation problem of a second order system with delayed input. The delay which affects the input is assumed to be bounded but uncertain. The behaviour of the system, under the action of the proposed control strategy, results to be a persisting oscillating one due to the delay of the input.
This paper explores the application of state-space methods to congestion and delay control in communication networks. In the absence of buffer under- or overflow, the transmission delay for packets moving through a congested link turns out to be a non-linear output of a system with linear dynamics. As a consequence, the congestion/delay control problem can be addressed, in the presence of input saturation,...
Interactions between trajectories need to be analyzed in various domains to gain insight into movement patterns. Such interactions often take place with some delayed response. We propose an approach to analyze and visualize delayed responses on two trajectories recorded simultaneously and with the same sampling rate. Central to our approach is the computation of a matching between the trajectories...
In this paper, we consider the problem of guaranteeing real-time end-to-end transmission time for flows sent on a Network-on-Chip (NoC) with First-in First-out (FIFO) scheduling on each node. We show how to adapt the Trajectory approach, used in the context of Avionics Full DupleX switched Ethernet (AFDX) networks to characterize end-to-end transmission delays, to the context of NoC-based Systems-on-Chip...
Real-time systems are highly complex and distributed. One of the major challenges in the design process of these systems is timing analysis. We are interested in an analytical method called the Trajectory Approach (TA). It allows upper bounding the end-to-end response time of any flow exchanged across a studied system. In particular, we are investigating the scalability of this approach when applied...
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