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A classic approach to obtain High Dynamic Range Images (HDRI) consists in combining multiple images of the same scene with varying exposures. However, if the scene is not static during the time of capture, moving objects will appear blurry and ghosted, i.e. in multiple locations. Detecting and removing ghosting artifacts is an important issue for automatic generation of HDRI of dynamic scenes. This...
The paper presents a small gain result for systems with jumps. As an application of this result, a state-feedback robust, stabilisation problem with respect, to parametric uncertainty of sampled-data systems is considered. A numerical example illustrates the theoretical developments.
This paper concerns the control of a camera, mounted on the end-effector of a robot manipulator, using a hybrid visual servoing scheme. Hybrid vision-based control consists in using information available directly at the image level jointly with the information reconstructed from two views of a rigid object (i.e. the displacement of the camera). The aim of this paper is to design a simple control law...
Volatility of the stock price is the key to the pricing problem of stock related derivatives in finance. Volatility appears in the diffusion term of the usual modeling of stock prices. One popular approach is to take volatility to be stochastic, and assumes that it satisfies a stochastic differential equation. Taking the stock price to be the observation, we may then pose the filtering problem of...
The robustness of discrete iterative learning controller a-gainst initial state state error for discrete-time plant is investigated in this paper. When the initial state remains fixed for each iteration but is different from the desired one, it is shown that the output will converge to a trajectory which is the same as the desired one except the initial point for a traditional D-type discrete iterative...
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.
A class of complex control systems, modelled as a finite family of stochastic differential equations with state-dependent noise is considered. Each individual equation of this family describes the plant state variable in individual regime of the system composed of a set of interconnected subsystems. The transitions between these regimes are discontinuous and are modelled by a homogeneous Markov chain...
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...
In this paper we study certain infinite-dimensional Sylvester equations. The equations are closely related to robust output regulation of infinite-dimensional systems. If the signal generator is finite-dimensional or has discrete spectrum and a complete set of orthonormal eigenvectors, there are some known sufficient conditions for the decomposing of these Sylvester equations. In this paper we generalize...
The fact that the feedback interconnection of strictly positive real (spr) systems leads to an asymptotically stable closed loop can be used for the synthesis of robust observer-based state-space controllers. Since most control plants originally are not spr structural modifications must be done to establish this property even under parameter variations. Going that way one gets a modified spr plant...
We face the problem of stabilizing Linear Parameter Varying systems by means of Gain Scheduling Control. This technique consists on designing a controller which is able to update its parameters on-line according to the variations of the plant parameters. We first consider the state feedback case and we show a design procedure based on the construction of a Lyapunov function for discrete-time LPV systems...
In this paper, H∞ approach is applied in order to design robust controllers for irrigation canals. From an automatic control point of view, an irrigation canal is a strongly coupled multi-variable system. More precisely, it is a cascade of sub-systems (pools) where the control input of each sub-system perturbs the previous sub-system. Control laws are usually obtained by designing monovariable controllers...
For both continuous and discrete-time cases, this paper presents a simple solution to the robust H∞ unbiased functional reduced order filtering problem via LMI methods in the presence of norm-bounded time-varying uncertainties. Necessary and sufficient conditions for the existence and the stability of the unbiased filter are given in the nominal case; the filter differs from that of 11] (only nominal...
In this paper, we propose a set-valued filtering algorithm for non-linear discrete-time systems. At each step, the algorithm computes an ellipsoid of minimal size that guarantees to contain the true state of the system, despite the noise affecting the system and taking into explicit consideration the linearization error. The filter is based on a two-step prediction-correction structure, each step...
In this paper we consider the problem of minimizing the H∞-norm of the sum of two systems which are interconnected with two different controller components. We sketch two specific applications of this decentralized control problem. As the main contribution, we reveal that this structured controller design problem admits a full LMI solution if only one of the systems in the interconnection obeys a...
This report presents a study on the problem of residual evaluation and threshold computation for detection of faults in continuous time nonlinear systems. A generalized framework for designing norm-based residual evaluation scheme is proposed. The problem of threshold computation is formulated as an optimization problem and its solution is developed using the well known LMI technique. Three commonly...
In this note we extend the design tool presented in [6] for robust stabilization of nonminimum-phase nonlinear systems to the case of output regulation problems. As in [6] we take advantage from a design tool known in the linear literature as “vibrational feedback” to handle the presence of unstable zero dynamics in output regulation problems in presence of uncertainties. This work frames in a research...
Previously, a nonlinear passivity control has been proposed for a discrete-time (neutrally) stable bilinear system. However, the decay rate of the closed-loop system is not exponential. In this paper, a new nonlinear control is suggested to achieve exponential decay rate. It is also shown that the new control is robust against small parametric uncertainties.
In this paper, robust fault detection using a parity equation passive robust approach based on generating an adaptive threshold considering that the system to be monitored can be described by an interval linear parameter varying (LPV) model with variable transport delay is proposed. This approach allows to consider parameters and associated uncertainty intervals dependence on the operating point....
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