1,720,988 research outputs found
Piecewise quadratic Lyapunov functions over conical partitions for robust stability analysis
No full textIn this paper, the robust stability problem for uncertain linear continuous‐time systems is faced making use of piecewise quadratic Lyapunov functions (PQLF). PQLF are obtained by partitioning the state space into polyhedral cones and by associating a quadratic form with each cone. The proposed formulation allows us to recover, as particular cases of PQLFs, not only the class of quadratic functions but also the class of polyhedral functions. In this way, we manage to show the universality of the class of PQLF for the robust stability problem. The main contribution of the paper is the formulation of a low‐computational cost procedure for the stability analysis of uncertain linear systems. Several numerical examples are included in the paper, where the proposed approach is tested on some benchmark cases taken from the literature. Comparisons with existing methods show that the proposed method performs better under several aspects
Constrained Control of Linear Discrete-Time Systems under Quartic Performance Criterion
Full text linkIn several applications, a performance criterion that is quartic in the state can be a desired alternative to the classic quadratic control. This letter proposes a receding horizon controller for linear time-invariant systems subject to linear state and input constraints, which makes use of a running cost that is quadratic in the input and quartic in the state. Stability and recursive feasibility of the proposed receding horizon scheme are proven. Numerical simulations are presented, considering the problem of controlling a single-link inverted pendulum on a cart.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Constrained control with communication blackouts: Theory and experimental validation over Wi-Fi
Full text linkMany modern applications have raised the issue of coordinating multiple agents under limitations given by the environment. In the industrial scenario, for instance, an interesting case-of-study consists of two mobile manipulators that cooperate to transport a load to a desired target position while avoiding obstacles. Wireless communications and physical constraints are the two key features of this kind of problems and the technological challenge is given by the merge of them: on one hand, constraints need to be always satisfied to guarantee safety, on the other, wireless networks are affected by random packet loss that usually allows only a probabilistic description of the system. Even more, if fast networks as Wi-Fi are adopted to achieve a low sampling period, the stochasticity of the communication is drastically increased and long communication blackouts are possible. For this reason, in this paper we focus on the case where the maximum number of consecutive packet losses is not bounded and we study a control scheme based on Reference Governor that guarantees to satisfy the constraints even in presence of communication blackouts. We provide the theoretical properties of the considered solution and we evaluate it through hardware-in-the-loop experiments based on actual realizations of a Wi-Fi channel obtained in laboratory
Wireless Sensor Networks Clock Synchronization with Selective Convergence Rate
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A constrained control framework for unmanned aerial vehicles based on Explicit Reference Governor
No full textThis paper tackles the constrained control problem of unmanned aerial vehicles with planar multirotors. The proposed solution splits the constrained control problem into two separate tasks, i.e. stabilization and constraint enforcement. It is shown that the problems addressed by each individual layer is much simpler than the original combined problem. For the unconstrained control of UAVs we consider a control scheme based on a cascade structure. The Lyapunov function for the stabilized cascaded system is then derived. Using this Lyapunov function, we develop an Explicit Reference Governor for constraint enforcement. Numerical simulation shows the effectiveness of the proposed approach
New conditions for finite-time stability of impulsive dynamical systems via piecewise quadratic functions
Full text linkIn this paper, the use of time-varying piecewise quadratic functions is investigated to
characterize the finite-time stability of state-dependent impulsive dynamical linear systems.
Finite-time stability defines the behavior of a dynamic system over a bounded time interval.
More precisely, a system is said to be finite-time stable if, given a set of initial conditions,
its state vector does not exit a predefined domain for a certain finite interval of time. This
paper presents new sufficient conditions for finite-time stability based on time-varying
piecewise quadratic functions. These conditions can be reformulated as a set of Linear
Matrix Inequalities that can be efficiently solved through convex optimization solvers. Dif ferent numerical analysis are included in order to prove that the presented conditions are
able to improve the results presented so far in the literature
Smart testing and selective quarantine for the control of epidemics
Full text linkThis paper is based on the observation that, during Covid-19 epidemic, the choice of which individuals should be tested has an important impact on the effectiveness of selective confinement measures. This decision problem is closely related to the problem of optimal sensor selection, which is a very active research subject in control engineering. The goal of this paper is to propose a policy to smartly select the individuals to be tested. The main idea is to model the epidemics as a stochastic dynamic system and to select the individual to be tested accordingly to some optimality criteria, e.g. to minimize the probability of undetected asymptomatic cases. Every day, the probability of infection of the different individuals is updated making use of the stochastic model of the phenomenon and of the information collected in the previous days. Simulations for a closed community of 10’000 individuals show that the proposed technique, coupled with a selective confinement policy, can reduce the spread of the disease while limiting the number of individuals confined if compared to the simple contact tracing of positive and to an off-line test selection strategy based on the number of contacts
Reference governor for constrained control over lossy channels
Full text linkIn real applications, plants are usually stabilized by local controllers, while wireless channels are only used to transmit the desired set-points, typically to satisfy constraints arising from coordination needs. Motivated by this fact, in this letter we consider to connect a pre-stabilized plant and a reference governor, a device that modifies the reference signal to satisfy the system constraints, over a wireless lossy network. First, we show that the reference governor formulation can be readily extended to manage packet losses on the uplink or on the downlink. Then, we show that, if both the links are lossy, the problem is more challenging due to information asymmetry between the governor and the plant. In this case, we analyze two different strategies: 1) a quantity to be added to the applied reference is sent and 2) a new reference that substitutes the applied one is sent. The theoretical properties of both strategies are proved. Simulations are reported which show that, depending on the case of study, none of the two solutions is a priori better than the other.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Clock Synchronization for Wireless Sensor Networks with Communication Delay
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