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In the paper, an improved nonsingular fast terminal sliding mode (INFTSM) guidance law with impact angle constraints is proposed. The guidance law, which employs a double power reaching law and an attractor with negative exponential factor, has a fast speed no matter far from the sliding surface or approach. For the maneuvering targets, extended state observer is designed through which the unknown...
In this paper, the simultaneous trajectory tracking of the speed and the flux state variables of induction machines is realized. Nonlinear feedback control laws are designed to make both the rotor speed and the flux variables reach the desired nominal values in finite time. In this study, the speed, the stator currents, and the flux are assumed to be available for measurement. Numerical simulations...
This paper deals with the design of a Proportional Multiple Integral (PMI) observer for Takagi-Sugeno systems with immeasurable premise variables subjected to unknown inputs. The introduction of an output error injection in the premise variable of the PMI observer allows to significantly reduce the conservatism of LMI-based stability conditions. A simulation example of a chaotic system is given to...
In this paper robust nonlinear observer and controller are designed for sensorless control of interior permanent magnet synchronous motor (IPMSM). The proposed method is based on the high order sliding mode technique. The super twisting algorithm is combined with an interconnected observer which allows using it in multi-input multi output case. The proposed controller computed using the MTPA strategy...
In this work a system for the estimation of the forces (both longitudinal and lateral) exerted between the tires and the road is presented. Starting from two of the most commonly used descriptions of the vehicle dynamics, the single-corner and the single-track models, a system composed of Sub-Optimal Second Order Sliding Mode observers in a cascade structure plus an adaptive element is developed and...
The purpose of the paper is to propose a new control scheme in active front steering (AFS) for vehicle stability using disturbance observer method. In the paper, the ideal yaw rate can be calculated on the linear two-degrees-of-freedom vehicle model. In addition, the actual sideslip angle can also be estimated by using a state observer. Based on this, two kinds of baseline AFS controllers are proposed...
This paper develops a sliding mode control (SMC) approach for a class of uncertain nonlinear systems with unmatched uncertainties/disturbances. The newly proposed method is based on a novel fixed-time convergent sliding mode disturbance observer which can estimate the unmatched disturbance in a fixed time (time whose upper estimate is independent of the initial conditions). By designing a novel sliding...
In this paper, an integral sliding mode based tracking control (ISMTC) scheme is proposed for a marine surface vehicle (MSV) in order to achieve accurate tracking performance. Salient features of the ISMTC scheme are as follows: (1) The integral sliding mode (ISM) technique is employed to realize accurate tracking performance, whereby a finite-time unknown observer is designed and integrated into...
For a class of nonlinear continuous systems, this paper proposes a sliding mode control with unidirectional auxiliary surfaces (UAS-SMC) based on a double power reaching law and a disturbance observer (DO). Firstly, according to the nonlinear continuous systems, the switching surfaces and the controller based on the proposed law and DO are designed to weaken the chattering phenomenon caused by disturbance...
This paper presents a novel approach for designing a composite controller that finite time simultaneously stabilizes two single input nonlinear Port-Controlled Hamiltonian (PCH) systems under disturbances. Firstly, using a single output feedback, two PCH systems are combined to generate an augmented PCH system based on the Hamiltonian structure properties. Then, a finite time disturbance observer...
We are concerned with the control issue for the joint angular of a one-DOF link manipulator in this paper by the active disturbance rejection control (ADRC) method. A novel extended state observer (ESO) is proposed to improve the convergence of the observer by adding and modifying a nonlinear region in the fal function. Taking the moment of the joint as a control input, the ADRC strategy is proposed...
In this paper, we will investigate the problem of continuous finite-time disturbance observer (CFTDO) design and its application in the finite-time control (FTC) for systems subject to non-vanishing disturbances. First of all, based on the homogeneous domination approach and state saturation technique, a CFTDO design approach is proposed such that the disturbance can be precisely estimated in finite...
The objective of this paper is to extend the relaxed conditions on the existence of the backstepping controllers and observers obtained in a recent literature to the case of parabolic Partial Differential Equations (PDEs) with the same diffusion. Moreover, an observer-based output feedback controller is designed for the considered systems with the new conditions. Then, the corresponding exponential...
In this study, we consider anti-windup design as one of the approaches for the boundary control problem of a flexible manipulator subject to input saturation and input disturbances. The dynamics of the system are represented by partial differential equation (PDE). One of the key contributions of this study is that using singular perturbation approach the PDE model is divided into two simpler subsystems...
We design four different parameter estimators for a class of 2 × 2 linear hyperbolic partial differential equations (PDEs) with uncertain transport speeds. The four methods are a) swapping design, b) estimation using infinite-dimensional ordinary differential equations (ODEs) c) estimation using finite-dimensional ODEs and d) identifier-based design. Boundedness of the estimates for all cases is proved,...
This note deals with the design of an invariant like nonlinear state observer for a two step (acidogenesis-methanogenesis) mass balance nonlinear model. In order to ensure the stability of the estimation error, a new LMI condition is proposed. The feasibility of this LMI is enhanced due to the use of a suitable reformulation of the Youngs inequality. Actually, additional decision variables are included...
This paper addresses the problem of position estimation for salient permanent magnet synchronous motors (PMSMs). It is assumed that stator currents and voltages and rotor speed are measurable signals. Two extensions of the position observer are presented — the first one is based on a standard gradient estimator and the second observer uses recently proposed the dynamic regression extension and mixing...
This note deals with the design of an H∞ nonlinear state observer for the anaerobic digestion model. Positively, the designed observer is an unified one that can be used for different class of systems, mainly linear systems, Linear Parameter Varying (LPV) systems with known and bounded parameters, and nonlinear Lipschitz systems. Applying the Lyapunov theory and the H∞ criterion, Linear Matrix Inequality...
This paper presents a continuous fixed-time observer-based controller driving all states of an n-dimensional chain of integrators to the origin for a finite pre-established (fixed) time using a scalar input, when only the highest relative degree state can be measured. The uniform upper bound for the controller convergence time is calculated. Performance of the developed controller is demonstrated...
In this paper, vibration control is addressed for a Timoshenko beam system with input backlash and external disturbances. By integrating iterative learning control into adaptive control, two dual-loop adaptive iterative learning control schemes are proposed in the presence of the input backlash. Two observers are designed to estimate two bounded terms, which are divided from the backlash inputs. Based...
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