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Renewable Energies (RE) are considered as an important alternative sources of energy for the generation of electricity such as hydrogen and photovoltaic energies. To ensure an efficient photovoltaic energy conversion several Maximum Power Point Tracking (MPPT) algorithms have been developed to incite the PV field to deliver maximum power. This paper presents a comprehensive comparative study of two...
Recently, sparse representation based classifiers (SRC) and collaborative representation based classifiers (CRC) have been shown to give very good performance under controlled scenarios. However, in practical applications, face recognition often encounters variations in illumination, expression, noise and occlusion, which cause severe performance degradation (due to the outliers in testing). In this...
In photovoltaic grid-connected inverter based on the deadbeat current control, the filter inductance variation and one-step-delay control affect the distortion of the grid current, stability and dynamic of the system. In this paper, a fast robust PWM method for photovoltaic grid-connected inverter is proposed, which reduces the distortion of the grid current caused by the filter inductance variation,...
This article demonstrates the possibilities of analyzing robust absolute stability of a temperature control system for an enclosed space (room, greenhouse etc.) by using an industrial drying cabinet as an example of such a closed space. The authors go tab transfer function with polynomials coefficients values of the numerator and denominator polynomials lying within intervals due to the possible range...
Conventional ring amplifier suffers from stability problem, the problem is exacerbated when process, voltage and temperature (PVT) variations are taken into considerations. Prior works are mainly focused on stability problem, the influence of PVT on transient response were barely discussed. In this paper the influence of process variations on stability and transient response is analyzed, a process-...
This paper studies the attitude control problem for the longitudinal motion of a hypersonic aircraft model containing 28 inertial and aerodynamic uncertain parameters given by NASA Langley Research Center. To handle the nonlinear dynamics and uncertain parameters, ADRC for the unobservable and unmatched disturbance is designed. Besides, the properties of the closed-loop system is discussed in two...
Small gain theorem is used to interpret stability and robustness of linear active disturbance rejection control(LADRC). For the case linear unmodeled dynamic and additive external disturbance, LADRC system is decomposed into two interconnected subsystems. The first subsystem includes all parametric uncertainty of the plant, while the second has a gain which can be adjusted by choosing the parameters...
A wheeled mobile robotic system (WMR) is a kind modular robotic, nonlinear and the system subjected to nonholonomic constraints. It is impossible to obtain an exact dynamics model due to unknown parameters, unpredictable and irregular features, external disturbance. This paper proposes an adaptive robust controller to guide WMR to follow the desired trajectory. The cascade control system is applied...
This paper studies the problem of robust H∞ control for uncertain stochastic system with time-varying delay. The time delay is assumed to be of interval type. By constructing a new stochastic Lyapunov-Krasovskii functional, Ito's formula and introducing free weighting matrix, sufficient conditions for delay-dependent robust H∞ control is obtained. The presented formulation is in the framework of linear...
On account of the finite propagation speed of signals, time-delay phenomena are abundant. Compared with time-delay systems, nonlinear systems with generalized piecewise constant arguments can be both of advance and retard, which are an extension to time-delay systems. In this paper, we address the robustness of global exponential stability for a general class of nonlinear systems with generalized...
This paper deals with the problem of robust output regulation for a set of Quad-Rotors forming a geometric pattern. The proposed control strategy is based on sliding- modes techniques, and it is able to robustly regulate the corresponding Quad-Rotors positions and angles in the presence of some class of disturbances acting on the Quad-Rotors. The proposed regulation is composed by cascaded continuous...
To improve the reliability of photovoltaic (PV) energy storage (PVES) system, the output voltage robust PI controller design criteria and method are proposed in this paper. First, the boost converter with an input capacitor is taken as an example, and its small signal model including the dynamic equivalent circuit of solar cell is built up. Based on this, the stable condition of the PVES system in...
A supplementary control method based on the internal model principle (IMP) is proposed to control damped oscillations. As a case study, low frequency oscillations threaten the stability and the performance of power systems. The challenge, however, is how to acquire the frequency and the damping of oscillations on-line since the parameters of oscillations are unknown in a power system. To design an...
We prove stability and robustness results for chemostat models with one substrate, an arbitrary number of species, a constant dilution rate, and constant inputs of the species. Unlike all previous works, we prove input-to-state stability under uncertainties in important cases where the controls are the input nutrient concentration and the species inputs. Our assumptions ensure global asymptotic stability...
This study is concerned with the problem of stability of two-dimensional (2-D) continuous systems in Roesser model, based on the Generalized Kalman-Yakubovich-Popov lemma combined with the frequency-partitioning approach. The objective is to propose a sufcient stability conditions of the systems, in order to reduce the conservativeness of the existing simple 2-D Lyapunov inequality, by introducing...
In this paper, a method based on stability boundary plot is considered for an unstable second order process with dead time. All the controllers that satisfy the gain margin and phase margin requirements are found by plotting the Kp-Ki curve. The technique is based on Kharitonov theorem for stability of interval plants. Limiting values of the controller parameters that stabilize the given system are...
In this paper, a method based on stability boundary plot is considered for an unstable second order process with dead time. All the controllers that satisfy the gain margin and phase margin requirements are found by plotting the Kp-Ki curve. The technique is based on Kharitonov theorem for stability of interval plants. Limiting values of the controller parameters that stabilize the given system are...
Robust control is becoming a necessity in almost all control fields. One method to achieve robust control in advanced control system is the two degree-of-freedom (2-DOF) control, in which two control loops will be assigned the performance and robustness goals separately. A Disturbance Observer (DOB), which is used in the designing of robust control systems, is a simpler and efficient tool. The applications...
This paper introduces a new algorithm for sliding mode control to stabilize a class of discrete-time nonlinear systems in the presence of uncertainties and external disturbances. The control algorithm is derived to guarantees the existing of quasi-sliding mode taking into accounts the upper bounds of uncertainties. As for the system stability, it can be found that the system is stabilized and finally...
This paper proposes an approach of Internal Model Control (IMC) for the linear sampled multivariable non-square systems with outputs more than inputs. The proposed IMC, which is based on a specific inversion principle, is the extension of to the case of square systems, in the controller design, a simple method is presented to add a complementary transfer function matrix of the process to obtain a...
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