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A nonlinear system model for a class of hydraulic device was constructed.On the basis of the conversion of its model,an exponent approaching law with variable parameter was adopted to realize the sliding mode control. A position tracking with high precision was realized,and it had a better disturbance-resistant ability . A boundary layer technique was used to reduce the chattering in sliding mode...
This paper proposes a new method of robust control system design based on Quality Engineering. The appropriate order of the controller in transfer function form and its numerical values of the parameters can be determined by using the proposed method. The method is applied to a benchmark problem of dual-mass/ nonlinear-spring system. The result shows that the controller has comparable robust performance...
Two memoryless adaptive observers are proposed for systems with unknown time-delays and nonlinearities, in which time-delays are not used in the observer. Using high order neural networks (HONN), the precise system model, the Lipschitz, linear-in-parameter or norm-bounded assumptions of nonlinear functions are not needed. A robust term based on the matching condition is introduced in the first observer,...
Fed-batch fermentation processes are common methods of producing biological recombinant from different microorganisms. Model-based control of bioprocesses is a difficult task due to the challenges associated with bioprocess modeling. The paper deals with the multilayer perceptron neural network modeling of fed-batch cultivation of E. coli BL21 (DE3) [pET3a-ifn??] under maximum attainable specific...
In this paper, a design approach is proposed for feedforward-feedback control systems. As the basis of the proposed design approach, steady state control command is defined as the control command which maintains the desired situation of the system. Steady state control law is derived form system's mathematical model and employed as feedforward controller. Using such a feedforward controller, for a...
The motion of typical aerodynamic systems can be simplified as the rigid multibody dynamics, such as applications on the vehicle dynamics and flight dynamics. The multibody dynamics represents the interaction among the individuals with large translational and rotational displacements. In the presence of parametric and nonparametric uncertainties, the stability issue is extremely critical to nonlinear...
The tracking control problem of muscular vessel systems with dynamic uncertainties and unknown parameters is studied. The unknown system parameters are adaptively identified, and the exogenous disturbance is attenuated by Nussbaum-type functions based on the backstepping methods. The derived adaptive robust controller guarantees that the closed-loop system is globally and uniformly bounded, and the...
Electrostatically actuated torsional micromirror fabricated using microelectromechanical systems (MEMS) technology is a fundamental building block for many optical network applications, such as optical wavelength-selective switch, configurable optical add-drop multiplexers and optical cross-connects. The major technical obstacle to achieve its full potentials in both functionalities and performance...
This paper presents an adaptive fuzzy controller for the robust backstepping control of a class of uncertain nonlinear systems in pure-feedback form. The proposed approach incorporates the Nussbaum gain function (NGF) and the dynamic surface control (DSC) into the existing adaptive fuzzy control scheme. The major features of the proposed method are that: 1) the two problems, control directions and...
This paper reports the basic properties and robust control of a vehicle-trailer combination crosswind disturbance conditions. In practice it is known that unstable roll movements may occur, especially with unfavorable combinations of vehicle and trailer conditions, operating slightly above the permissible maximum speed. This may lead to accidents mostly due to improper driver behavior. First we present...
This paper proposes a general method for dealing with state estimation under nonlinear state soft inequality constraints. This method is based on the projection approach, and then has the advantage to be compatible with any kind of state estimator. In order to be taken into account, the nonlinear constraints are linearized about the constrained state using an iterated approach. The proposed algorithm...
This paper deals with the design of reduced order observers for a class of nonlinear descriptor systems. The order of these observer is qlesn , where n is the dimension of the semi state. A new method is presented, the conditions for the existence of these observers are given and sufficient conditions for their stability are derived using linear matrix inequalities (LMIs) formulation. A numerical...
An estimation of the state and the unknown inputs of the reduced nonlinear model of an activated sludge process using the Extended Kalman Filter (EKF) is proposed. First, we present the reduced nonlinear model. This model contained five state variables and four unknown inputs. For satisfying the rank condition for the construction of an EKF, one unknown input has been approximated and the daily mean...
The paper deals with robust predictive control based on a LMI approach. With respect to the well established case of linear models, with a global polytopic uncertainty, in the present approach the conservativeness reduction is assured by allowing different local descriptions of the uncertainty. The prediction model can thus be interpreted as a multi-model description of the plant to be controlled...
We consider the adaptive control problem for a class of SISO unknown nonlinear systems in the presence of additive input disturbances, with guaranteed prescribed performance. By prescribed performance we mean that the tracking error should converge to an arbitrarily predefined small residual set, with convergence rate no less than a prespecified value, exhibiting a maximum overshoot less than a sufficiently...
In the paper a hierarchical optimization method for complex systems, including control systems , characterized with replacement of the nonlinear global criterion function F(x,y) with a simpler and faster for calculation one - Psi (x,y) (unidirectional with F(x,y) ) for a subset of variable parameters in the second hierarchical level is suggested. A definition of unidirectional functions is proposed...
This paper recapitulates the adaptive (time- varying) control strategy funnel-control (FC) and introduces its direct derivative error reference control (ERC) with specially designed Funnel boundaries and auxiliary reference. Both controller designs are comparatively applied to a nonlinear two-mass flexible servo system for speed control. ERC (as derivative of FC) is based on the high-gain controllability...
This paper presents a new approach for on-line identification of an exact affine model for single-input, single- output (SISO) processes with nonlinear and time-varying behaviors. For this purpose, a modified growing and pruning algorithm for radial basis function (MGAP-RBF) neural network is used for affine modeling of the SISO nonlinear and time-varying processes. The extended Kalman filter (EKF)...
A new approach for the design of robust static output feedback controller for a class of discrete-time Lipschitz nonlinear systems with time-varying uncertainties is proposed based on linear matrix inequalities. The controller has also a guaranteed disturbance attenuation level (Hinfin performance). Thanks to the linearity of the proposed LMIs in both the admissible Lipschitz constant of the system...
The design problem of mixed L2, H2 gain scheduling nonlinear state feedback controller for Linear Parameter Varying (LPV) systems subjected to actuator saturations and L2 bounded disturbances is considered. First, a new formulation of H2 controllers has been presented based on the homogeneous polynomial parameter dependent (HPPD) representation. Then a systematic procedure to generate a sequence of...
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