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Different variations of the covariance matrix adaptation evolution strategy (CMA-ES) are used in the design and optimization of electromagnetic (EM) problems. Two different schemes for the implementation of mixed-parameter CMA-ES and one scheme for the implementation of multiobjective CMA-ES are presented. Mixed-parameter CMA-ES is attractive in EM optimization when both continuous and discrete design...
The present research work aims at the development of a systematic method to arbitrarily assign the zero dynamics of a nonlinear system by constructing the requisite synthetic output maps. The minimum-phase synthetic output maps constructed can be made statically equivalent to the original output maps, and therefore, they could be directly used for nonminimum-phase compensation purposes. Specifically,...
The problem of estimating the state of a discrete-time linear system can be addressed by minimizing an estimation cost function depending on a batch of the recent measurement and input vectors. This problem has been solved by introducing a general receding-horizon objective function that includes also a weighted penalty term related to the prediction of the state. For such an estimator, convergence...
Deterministic finite state automata can be modelled within the framework of the boolean differential calculus. One way back to conventional arithmetics leads to multi-linear discrete models of the automata. There the escrow issue is that even if state feedback is applied, in general the models still remain nonlinear. The method presented here is to embed the nonlinear state space within a linear state...
This paper presents a novel output-based, discrete-time, sliding mode controller design methodology Output based controllers with and without disturbance estimation are presented. First several existing discrete-time reaching conditions are analyzed and compared. From these methods the linear reaching law is selected to form the basis for the output-based controller design.
The problem of determining spacecraft attitude and angular rates from vector measurements is analysed; a number of approaches to the problem are compared and their relative merits discussed with particular reference to the problem of attitude and rate determination from magnetic field vector measurements.
The open loop optimal control (dynamic optimization) of distributed parameter systems is considered here. These problems are usually solved by the Control Vector Parameterization (CVP) approach, which transforms the original dynamic optimization method into an outer nonlinear programming problem, which requires the solution of an inner initial value problem (IVP). The solution of this IVP (set of...
In 1996, a new spread spectrum communication system, called Frequency Diversity Spread Spectrum (FDSS), was proposed as a system to mitigate the problems of the common spread spectrum techniques. In this paper, two blind self-reference optimum beamforming methods tailored for the FDSS signalling scheme using the trivial repetition code are derived based on the inherent cross-correlation properties...
Control design methods for the control of the reaction wheel pendulum using a single actuator are presented in this paper. The control algorithms are based on the energy of the system and its passivity properties.
This article deals with modeling and identification of fractional systems in the time domain. Fractional state-space representation is defined, and a stability condition for fractional systems given. A new identification method for fractional systems is then proposed. The method is based on the generalization to fractional orders of classical methods based on State Variable Filters (SVF). A particular...
In this paper, a sensor fault diagnosis and accommodation method is developed in nonlinear case. This method makes possible the sensor faults compensation. Its principle is based on the on-line detection, localization and estimation of a faulty element when a fault occurs on a nonlinear system. Then, a new control law is computed in order to compensate the fault effect on the system. The performances...
The new approach of robust control systems synthesis, both linear, and nonlinear and non-stationary is offered. The control is carried out, providing the given phase constrains varied in acceptable limits, in view of constrains on its value and incompleteness of the information about functioning disturbances. The approach is based on introduction of auxiliary integral surfaces, on which the initial...
The problem of observer design for robust residual generation in nonlinear discrete-time systems is considered. The method is proposed to solve this problem involving nonlinear time-dependent transformation of state-space system model into strict feedback form. To make this transformation practicable, algebra of time-dependent functions is developed.
In this paper a control algorithm for the reduced port-Controlled Hamiltonian model (PCH) of the shallow water equations (PDEs) is developed. This control is developed using the Interconnection and Damping Assignment Passivity Based Control (IDA-PBC) method on the reduced PCH model without the natural dissipation. It allows to assign desired structure and energy function to the closed loop system...
This paper discusses the state feedback stabilization problem of a deterministic finite automaton (DFA), based on its state equation representation recently proposed by the authors. First, a linear state equation representation of the DFA is briefly explained. Next, after the notion of equilibrium points and stabilizability of the DFA are defined, a necessary and sufficient condition for the DFA to...
The paper presents a method for decentralized global formation stabilization of a group of several autonomous vehicles described by the standard kinematics equation with hard constraints on the vehicles' linear and angular velocities.
An output feedback robust controller based on sliding modes and indirect adaptive control called Indirect Variable Structure Model Reference Adaptive Control (IVS-MRAC) was recently proposed for relative degree one LTI plants, suggesting to be globally asymptotically stable with superior transient behavior and disturbance rejection properties. In this paper, some remarkable simplifications are carried...
The paper considers an example of mechanical system with high relative degree: a fully actuated robot with elastic joints and the related control problem. The considered system is characterized by a uniform relative degree five, assuming as available output only the joints' angles. Two different strategies can be exploited to address this control problem. A first possibility is to use a full order...
This paper forms a part of a series of recent studies we have undertaken, where the problem of nonlinear signal modelling is examined. We assume that an observed "output" signal is derived from a Volterra filter that is driven by a Gaussian input. Both the filter parameters and the input signal are unknown and therefore the problem can be classified as blind or unsupervised in nature. In...
In this paper a nonlinear robust control strategy designed for underactuated mechanical systems is proposed in order to solve the path tracking problem for a quadrotor unmanned aerial vehicle. An underactuated nonlinear ℋ∞ controller based on the six degrees of freedom dynamic model is designed to control the helicopter attitude and altitude in the inner-loop. The outer-loop control is performed using...
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