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A nonlinear suboptimal guidance scheme is developed for the reentry phase of the reusable launch vehicles. A recently developed methodology, named as model predictive static programming (MPSP), is implemented which combines the philosophies of nonlinear model predictive control theory and approximate dynamic programming. This technique provides a finite time nonlinear suboptimal guidance law which...
In this paper a nonlinear optimal controller has been designed for aerodynamic control during the reentry phase of the reusable launch vehicle (RLV). The controller has been designed based on a recently developed technique optimal dynamic inversion (ODI). For full state feedback the controller has required full information about the system states. In this work an extended Kalman filter (EKF) is developed...
Switched and piecewise affine models are interesting when modeling a nonlinear and non stationary complex system. Identification of these models is a challenging problem that involves estimation of both the parameters of the submodels, and the partitioning of state and input space. In this paper, we introduce a subspace technique for identification of the class of multi-variable hybrid complex system...
The paper deals with continuous-time adaptive control of a MIMO nonlinear process. A nonlinear model of the process is approximated by a continuous-time external linear model. Its parameters are estimated via an external delta model with the same structure as the CT model. The control system configuration with two feedback controllers is considered. For controllers design, the polynomial approach...
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...
This paper presents the excitation control design of a synchronous generator aimed at voltage regulation in power systems. The design is based on the use of the direct feedback linearization technique. With the help of this technique, a nonlinear output variable is set up which makes the nonlinear model linear versus a new input. Subsequently this new input, which represents the output of a feedback...
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...
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 main goal of this paper consists in the development of a new actuator fault-tolerant control dedicated to nonlinear systems. Based on the assumption that the nonlinear system is described by a finite number of interpolated linear time invariant models, the proposed method makes possible the faults compensation for the whole operating range through an extended interacting multiple model. Its principle...
This paper deals with the problem of state estimation of nonlinear uncertain systems described by uncertain multiple model form with unmeasurable decision variables. We propose two methods to attenuate the effect of modeling uncertainties and measurement noise on the state estimation. The first method is based, under some assumptions, on the second method of Lyapunov and L2 approach. The second method...
This paper addresses fault detection and isolation (FDI) problem using a sliding mode fuzzy observer on the basis of a uncertain Takagi-Sugeno (T-S) fuzzy model. First, a robust fuzzy observer with respect to the uncertainties is designed. The convergence of the fuzzy observer is performed by the search of suitable Lyapunov matrices. It is shown how to synthesis observers using a set of linear matrix...
This paper deals with intelligent controller design using artificial neural networks (ANN) in the role of feedback controllers. Neural controllers are built up and trained as inverse neural process models. Their performance and robustness are, gradually, improved and augmented by introducing, first, an adaptive simple integrator and, then, a controller with fuzzy integrator part. The proposed ANN...
The problem of robust trajectory tracking control, with a guaranteed Hinfin performance, for constrained manipulator systems subject to uncertainties and external disturbances is solved in this paper. A control strategy is developed based on the robot mathematical model and an adaptive fuzzy approach. The adaptive fuzzy control law is based on Takagi-Sugeno model, which is proposed to estimate the...
In this paper, a fuzzy adaptive control system is investigated for a class of uncertain multi-input multi-output (MIMO) nonlinear systems with both unknown backlash hysteresis and unknown sign of the control gain matrix. To deal with the unknown sign of the control gain matrix, the Nussbaum-type function is used. In the designing of the fuzzy adaptive control scheme, we will exploit a decomposition...
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...
In this paper, the design of a two-level controller is proposed for active suspension systems. The required control force is computed by applying a high-level controller, which is designed using a linear parameter varying (LPV) method. The suspension structure contains nonlinear components, i.e. the dynamics of the dampers, the springs and the actuator dynamics. The actuator generating the necessary...
This paper gives the necessary conditions for existence of the output and state coordinate transformations, allowing to transform the nonlinear single-input single-output control system into the observer form. The suggested conditions strengthen the existing ones. The new conditions require (additionally) the certain n 1-forms to be closed.
This paper presents a nonlinear predictive control strategy for maximizing the biomass growth in fed-batch cultures of E. Coli. This objective is achieved by regulating the acetate concentration at a low measurable value, while tracking (in a compromising way) an optimal glucose feed-rate trajectory determined off-line. Robustness with respect to model uncertainties is improved by taking system/model...
This paper addresses higher order sliding mode control for continuous linear systems. We propose a new method of reaching control design while the sliding surface and equivalent control can be designed conventionally. The high order derivatives of the sliding surface and the sliding surface itself are forced to zero in an n-th order sliding mode scheme. This is realized by an optimization based on...
In this paper, the nonlinear sliding-mode control combined with the backstepping approach for a three tank system is proposed. The recursive nature of this approach is similar to the standard backstepping, and the difference is that we use backstepping to design virtual controller including a zero-order sliding mode at each recursive step. Stability analysis results are discussed, which show that...
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