Showing papers by "Francesco Amato published in 1996"
TL;DR: This paper provides necessary and sufficient conditions for quadratic stabilizability both for the state and the output feedback case in linear time-varying systems subject to norm bounded, one block, structured uncertainties.
Abstract: In this paper we consider linear time-varying systems subject to norm bounded, one block, structured uncertainties. First, given an unforced system, we find necessary and sufficient conditions for quadratic stability; then, considered a controlled system, we provide necessary and sufficient conditions for quadratic stabilizability both for the state and the output feedback case.
29 citations
15 Sep 1996
TL;DR: In this paper, the problem of controlling the current in an electric arc heater by means of the delay angle of a 70 MW electric power system thyristor bridge is considered, and a control scheme consisting of two actions is proposed to guarantee the current regulation inside the arc heater.
Abstract: In this work we deal with the problem of controlling the current in an electric arc heater by means of the delay angle of a 70 MW electric power system thyristor bridge. To guarantee the current regulation inside the arc heater we propose a control scheme consisting of two actions: a feedforward control action obtained off-line by means of a numerical nonlinear inversion of the model and implemented on-line with a look-up table to guarantee the perfect regulation in absence of external disturbances, and an output feedback control action to counteract possible disturbances acting during the operating of the arc heater. Since the electric linearized model depends on a number of uncertain parameters, the feedback control action is designed so as to guarantee robust stabilization of the closed loop; moreover constraints regarding the speed of convergence are imposed. Simulation results are provided for the whole nonlinear scheme.
7 citations
01 Jan 1996
TL;DR: This chapter has considered linear systems subject to parametric uncertainties and the quadratic stabilization problem referred to a fictitous system depending multiaffinely on parameters, via convex optimization procedures.
Abstract: In this chapter we have considered linear systems subject to parametric uncertainties. The quadratic stabilization problem can be solved in an elegant way, via convex optimization procedures, if the dependence of the system matrices on parameters is the ratio of multiaffine polynomials. In the other cases we can use an algorithm which, under mild assumptions, transforms a given nonlinear matrix function into a multiaffine one. Via this algorithm and at the price of some conservatism, we can solve the quadratic stabilization problem referred to a fictitous system depending multiaffinely on parameters. An algorithm to reduce such conservatism has also been presented.
7 citations
TL;DR: In this article, the problem of designing a flight control system for the tracking of parabolic trajectories to guarantee microgravity conditions within the aircraft cabin is considered, and the proposed control action consists of two parts: a feedforward control guaranteeing good tracking of the desired parabola in the absence of environmental disturbances.
Abstract: The problem of designing a flight control system for the tracking of parabolic trajectories to guarantee microgravity conditions within the aircraft cabin is considered. The proposed control action consists of two parts. The first one is a feedforward control guaranteeing good tracking of the desired parabola in the absence of environmental disturbances. The second part is a gain-scheduled output feedback to counteract possible misalignments between the desired output trajectory and the actual one. An estimation of the maximum output displacement in the presence of uncertainties and disturbances (wind gusts) is carried out. Simulation results are provided for a remotely piloted vehicle.
4 citations
TL;DR: In this paper, the problem of designing a controller which guarantees the quadratic stabilization of the closed-loop system while keeping the norm of the operator mapping the exogenus input to the controlled output under a prespecified level is considered.
3 citations
TL;DR: In this paper, a linear time-varying uncertain system depending in structured, norm-bounded, one-block fashion on an uncertain, real, time varying parameter whose magnitude is between the complex stability radius and the real stability radius, is considered.
11 Dec 1996
TL;DR: This paper provides sufficient conditions guaranteeing that the input-output operator associated to the system has H/sup /spl infin// norm less than a prespecified positive number /spl gamma/.
Abstract: In this paper we deal with linear time-varying systems defined over a finite interval of time and subject to multiblock, norm bounded uncertainties. We provide sufficient conditions guaranteeing that the input-output operator associated to the system has H/sup /spl infin// norm less than a prespecified positive number /spl gamma/. Our formulation takes into account a constraint on both the initial and the terminal state of the system.