Showing papers on "Terminal sliding mode published in 2007"

Second-order terminal sliding mode control of uncertain multivariable systems

Abstract: A second-order terminal sliding mode controller for uncertain multivariable systems is proposed in this paper. The controller adopts the hierarchical control structure. The paper derives the state transform matrices which are used to transform a multivariable linear system to the block controllable form consisting of two subsystems, an input-output subsystem and a stable internal dynamic subsystem. The proposed controller utilizes a non-singular terminal sliding mode manifold for the input-output subsystem to realize fast convergence and better tracking precision. Meanwhile, a chattering-free second-order terminal sliding mode control law is presented. The stability of uncertain multivariable systems can be realized using the proposed controller. A derivative estimator is utilized in the paper to estimate the derivatives of the sliding mode functions for the controller. The simulation results are presented to validate the design method.

A novel dynamic terminal sliding mode control of uncertain nonlinear systems

Abstract: A new dynamic terminal sliding mode control (DTSMC) technique is proposed for a class of single-input and single-output (SISO) uncertain nonlinear systems. The dynamic terminal sliding mode controller is formulated based on Lyapunov theory such that the existence of the sliding phase of the closed-loop control system can be guaranteed, chattering phenomenon caused by the switching control action can be eliminated, and high precision performance is realized. Moreover, by designing terminal equation, the output tracking error converges to zero in finite time, the reaching phase of DSMC is eliminated and global robustness is obtained. The simulation results for an inverted pendulum are given to demonstrate the properties of the proposed method.

Hierarchical Longitudinal Controller for Rear-End Collision Avoidance

Abstract: Rear-end collision is a very serious problem in modern traffic situations, and there have been a great number of research reports on the longitudinal control method for road vehicles. In many cases, however, the control problem is formulated under platoon configuration and for some predictable noncollision situations. For predictable collision situations, regional and hierarchical approaches have been employed, but these approaches render difficulties due to ignorance for modeling error and logical error in a decision process. In this paper, the vehicle control for collision avoidance is studied with two control objectives, i.e., minimization of the safety distance error and regulation of the relative velocity between two vehicles. For this, a longitudinal controller using terminal sliding mode (TSM) with hierarchical structure is proposed for rear-end collision avoidance. The TSM is employed to achieve convergence in finite time, while the hierarchical approach is used for the system to accommodate the intelligence of the driver to handle various situations. The effectiveness of the proposed control scheme is verified by software simulations

Stabilization of the attitude of a rigid spacecraft with external disturbances using finite-time control techniques

Abstract: In this paper, we discuss the classical problem of attitude stabilization for a rigid spacecraft with external disturbances Almost all the control laws for attitude stabilization problem in the literature can only guarantee at best exponential convergence of the attitude with infinite settling time We employ finite-time control techniques including terminal sliding mode approach and continuous finite-time control approach to develop feedback control laws for stabilizing spacecraft attitude in terms of Rodrigues parameters The attitude of the rigid spacecraft will be stabilized to the origin in finite time in the absence of disturbances and a small region of the origin in the presence of disturbances Rigorous proof is given Numerical simulation results show the effectiveness of the method

Stabilization of an Underactuated Surface Vessel via Discontinuous Control

Abstract: The stabilization problem of an underactuated surface vessel is addressed in this paper. A discontinuous control approach with two stage control laws switched on at given time is proposed based on the stability analysis of the global transformed system. With the aid of terminal sliding mode (TSM) method, the two asymptotically stabilizing control laws for the transformed subsystems are designed independently. It is shown that the proposed discontinuous approach asymptotically stabilizes the underactuated surface vessel. Numerical simulation results are given to illustrate the effectiveness of the proposed approach.

Terminal sliding mode control for MIMO T-S fuzzy systems

Abstract: In this paper, we present a terminal sliding mode control for MIMO T-S fuzzy systems. It is shown that the concept of extreme matrices is used to determine the upper bound information of the interactions of the fuzzy subsystems first, and a terminal sliding mode controller and a set of sliding variables are then designed to enable finite time reachability of the system origin. Simulation results are presented in support of the proposed approach.

Chaotic synchronization problem of finite-time convergence based on fuzzy sliding mode

Abstract: The problem of finite-time synchronization for chaotic system is proposed. By applying the global sliding mode control technique and selecting the exponential fast terminal sliding mode reaching law, a global sliding mode controller is designed and applied to synchronization of a class of chaotic systems. Aimed at the chaotic system with parameter uncertainties and disturbance, fuzzy basis function network is introduced to on-line estimate the parameter bound. The design scheme eliminates the reaching phase of sliding mode control. The tracking error stays on the sliding mode surface and tends to zero in finite time. To verify the feasibility and effectivness of this control strategy, the synchronization for Duffing chaotic system is illustrated.

Terminal sliding mode control of nonlinear chaotic systems using self-recurrent wavelet neural network

Abstract: In this paper, we design a self-recurrent wavelet neural network (SRWNN) based terminal sliding mode controller for nonlinear chaotic systems with uncertainties. The nonlinear chaotic systems are decomposed into a sum of a nominal nonlinear part and uncertainty term. The terminal sliding mode control (TSMC) method which has been used to control the system robustly can drive the tracking errors to zero in a finite time. In addition, the TSMC has the advantages such as improved performance, robustness, reliability and precision by contrast with the classical sliding mode control (CSMC). For the control of nonlinear chaotic system with various uncertainties, we employ the SRWNN which is used for the prediction of uncertainties. The weights of SRWNN are trained by adaptive laws based on Lyapunov stability theorem. Finally, we carry out simulations on two nonlinear chaotic systems such as Duffing system and Lorenz system to illustrate the effectiveness of the proposed control.

Adaptive Fuzzy Multi-surface Sliding Mode Control for A Class of Nonlinear Systems

Abstract: An adaptive fuzzy multi-surface sliding mode control is proposed for a class of nonlinear systems with mismatched uncertainties. It is shown that the Mamdani fuzzy logic-based function approximator is used to learn the system uncertainties first, and the iterative multi-surface sliding mode design is then carried out. Using the concept of terminal sliding mode to design the baseline controller, not only strong robustness with respect to approximation errors and nonlinearities can be obtained, but also the tracking error can be proven to converge to a small neighborhood of the origin in finite time. Simulation results are provided to show the effectiveness of the proposed approach.

Synchronization of chaotic systems with uncertainties using robust terminal sliding mode control

Abstract: A novel robust terminal sliding mode control based on fast fuzzy disturbance observer is designed for a class of chaotic systems with uncertainties. To deal with the shortcoming of slow learning of traditional fuzzy disturbance observer when the approximation errors are very small, a fast fuzzy disturbance observer is designed which improves the learning speed. It is rigorously proved that the synchronization error and approximation error converge to very small values in finite time. Finally, simulation results of the Duffing-Holmes chaotic system demonstrate the effectiveness of the presented closed-loop control scheme.

Study on the steady precision of sliding mode control for a class of nonlinear systems

Abstract: For the steady precision of linear sliding mode control and Terminal sliding mode control for a class of nonlinear systems,the numerical relationship between the steady errors of linear sliding mode control systems and Terminal sliding mode control systems with a saturation function instead of the sign function in the sliding control law and the width of the saturation function is analyzed.Mathematical formulas between the steady errors and the width of the saturation function are deduced,which provides the theoretical basis for the choice of the width of the saturation function used to weaken the chattering of sliding mode control system and guarantee the steady precision simultaneously.Steady precision is quantitatively compared between linear sliding mode control and Terminal sliding mode control,which shows that Terminal sliding mode control performs better than linear sliding mode control in steady precision.A numerical simulation example proves the validity of the theoretical analysis in the end.

Adaptive terminal sliding mode control and its applications for UASV re-entry

Abstract: Aiming at the shortcomings of traditional fuzzy disturbance observer, a novel fast fuzzy disturbance observer is designed. Then an adaptive terminal sliding mode control with fast fuzzy disturbance observer is proposed. It is proved that the tracking errors and approximation errors converge to very small regions in finite time. Finally, the simulation results show the effectiveness of presented schemes.

The Design of Terminal Sliding Controller of Two-Link Flexible Manipulators

Abstract: A terminal sliding mode controller is proposed for a two-link flexible manipulator to address its non-minimum phase characteristics using the output redefinition method. The manipulator system is decomposed into two parts by input-output linearization, namely an input-output subsystem and the zero dynamics respectively. Then a terminal sliding mode control strategy is designed to make the input-output subsystem converge to zeros in finite time. The relationship between the eigenvalues of the zero dynamics and the parameters of the redefined output is obtained. Moreover, the zero dynamics can be asymptotical stable at equilibrium point by choosing suitable controller' parameters. The whole original two-link flexible manipulator control system is guaranteed to be asymptotically stable and the control design procedure is simple and easy to implement. Simulation results are presented to validate the design.

Nonsmooth finite-time control of uncertain second-order nonlinear systems

Abstract: Nonsmooth finite-time stabilizing control laws have been developed for the double integrator system. The objective of this paper is to further explore the finite-time tracking control problem of a general form of uncertain second-order affine nonlinear system with the new forms of terminal sliding mode (TSM). Discontinuous and continuous finite-time controllers are also developed respectively without the singularity problem. Complete robustness can be acquired with the former, and enhanced robustness compared with the conventional boundary layer method can be expressed as explicit bounded function with the latter. Simulation results on the stabilizing and tracking problems are presented to demonstrate the effectiveness of the control algorithms.

A Scheme of Integrated Guidance/Autopilot Design for UAV Based on TSM Control

Abstract: A scheme for integrated guidance/autopilot design for some UAV based on terminal sliding-mode (TSM) control is proposed. Firstly, the terminal sliding mode control is introduced, then a guidance/control law is designed based on TSM control and the backstepping idea when an integrated guidance/autopilot model on the yaw plane of some UAV is formulated. Secondly, for the unavailable information of the maneuvering target, an estimating method is given and an auxiliary control based on a sliding mode estimator is used to offset the estimation error. Finally, a simulation of some UAV against high maneuvering targets on the yaw plane was made to verify the effectiveness and rightness of the scheme, and the simulation results have shown that good offensive performance can be got.

Terminal Sliding Mode Control for Singular Systems with Unmatched Uncertainties

Abstract: A sliding mode control method is proposed for a class of multiply input and multiply output (MIMO) linear singular systems with unmatched uncertainties. Firstly, the singular system is transformed into the normal system by a derivative state feedback controller under the assumption that system is strong controllable. And then a terminal sliding mode manifold is designed and the control law is driven to reach the terminal sliding mode surface in finite time and converge to the neighborhood of equilibrium point in finite time once they are on the sliding mode manifold. The neighborhood of equilibrium is related with the range of unmatched uncertainties and parameters of terminal sliding mode. Finally, simulation example validates the design method.

Research of Terminal Sliding Mode Control Based on Fast Fuzzy Disturbance Observer for UASV Re-Entry

Abstract: A Terminal sliding mode control(TSMC) based on fast fuzzy disturbance observer(FFDO) is proposed for the UASV re-entry with violent changes of aero-dynamics parameters.To achieve high precision,an FFDO is designed which improves the approximation ability of the observer on-line.The finite time convergence characteristic of TSMC improves the tracking speed of the flight control system.Combining TSMC with FFDO,the flight quality is guaranteed.Finally,the simulations demonstrate the superiority of the FFDO and the effectiveness of the closed-loop control scheme.

A novel dynamic terminal sliding mode control of uncertain nonlinear systems

Abstract: 滑动模式控制(DTSMC ) 技术的一个新动态终端是建议的论坛班单个输入、单个产量(SISO ) 不明确的非线性的系统。动态终端 liding 模式控制器基于 Lyapunov 理论被提出以便靠近环的控制系统的 thes liding 阶段的存在能被保证，啁啾切换的控制行动引起的现象能被消除，并且高精确性能被认识到。而且由设计终端方程，追踪错误的输出在有限时间收敛到零， DSMC 的到达阶段被消除，全球坚韧性被获得。一只转换摆钟的模拟结果被给表明建议方法的性质。

Fast terminal sliding mode tracking controller design for nonholonomic mobile robot

Abstract: In order to realize the trajectory tracking control of mobile robots,a fast terminal sliding mode tracking controller based on the dynamic model is presented for nonholonomic mobile robot.Based on the combination of the backstepping method and the thought of the fast terminal sliding mode control,the controller can make the mobile robot track the desired trajectory in the global sense as well as in finite time.The method of the controller breaks down the nonholonomic mobile robot system into low dimensional subsystem and simplifies the controller design using virtual control inputs.Moreover,the controller design process is very easy.Simulation results are provided to illustrate the correctness and flexibility of the controller.

Synchronization of Chaotic Systems Using Terminal Sliding Mode Control

Abstract: A terminal sliding mode controller of a class of second-order chaotic systems is studied on the basis of drive-response synchronization.The finite time synchronization of chaotic systems is realized by designing a continuous terminal sliding mode controller with an improved sliding surface introduced to get rid of the singularity phenomenon resulting from improper choice of parameter.Simulation results showed that the modified terminal sliding controller will not only reduce the chattering effectively but also improve the track ability and steady accuracy of the system,thus enabling the finite-time synchronization of chaotic systems to come true.

Terminal Sliding Mode Control of Nonlinear Systems Using Self-Recurrent Wavelet Neural Network

Abstract: In this paper, we design a terminal sliding mode controller based on self-recurrent wavelet neural network (SRWNN) for the second-order nonlinear systems with model uncertainties. The terminal sliding mode control (TSMC) method can drive the tracking errors to zero within finite time in comparison with the classical sliding mode control (CSMC) method. In addition, the TSMC method has advantages such as the improved performance, robustness, reliability and precision. We employ the SRWNN to approximate model uncertainties. The weights of SRWNN are trained by adaptation laws induced from Lyapunov stability theorem. Finally, we carry out simulations for Duffing system and the wing rock phenomena to illustrate the effectiveness of the proposed control scheme.

Terminal Sliding Mode Control of the Delayed System by Adopting Derivate Estimator

Abstract: The paper proposes a terminal sliding mode control for the delayed input system with matched uncertainties. Through the state transformation, the delayed input system with uncertainties is transformed into the non-delayed controllable canonical form For the controllable canonical form, the paper designs a terminal sliding mode and terminal sliding control law with the Lyapunov method that makes both the reaching time of the any initial state and the converging time to the equilibrium points is in finite time. During the designation of the terminal sliding mode, a derivate estimator is adopted. The simulation results show the validation of the method.