Home About us Contact
|
Home About us Contact | ||
|
|
||
Tracking Problem (tracking + problem)
Selected AbstractsIndirect adaptive control of a class of marine vehiclesINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2010Yannick Morel Abstract A nonlinear adaptive framework for bounded-error tracking control of a class of non-minimum phase marine vehicles is presented. The control algorithm relies on a special set of tracking errors to achieve satisfactory tracking performance while guaranteeing stable internal dynamics. First, the design of a model-based nonlinear control law, guaranteeing asymptotic stability of the error dynamics, is presented. This control algorithm solves the tracking problem for the considered class of marine vehicles, assuming full knowledge of the system model. Then, the analysis of the zero-dynamics is carried out, which illustrates the efficacy of the chosen set of tracking errors in stabilizing the internal dynamics. Finally, an indirect adaptive technique, relying on a partial state predictor, is used to address parametric uncertainties in the model. The resulting adaptive control algorithm guarantees Lyapunov stability of the errors and parameter estimates, as well as asymptotic convergence of the errors to zero. Numerical simulations illustrate the performance of the adaptive algorithm. Copyright © 2009 John Wiley & Sons, Ltd. [source] Global output regulation for output feedback systems with an uncertain exosystem and its applicationINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 15 2010Dabo Xu Abstract This paper presents the solvability conditions for the global robust output regulation problem for a class of output feedback systems with an uncertain exosystem by using output feedback control. An adaptive control technique is used to handle the unknown parameter vector in the exosystem. It is shown that this unknown parameter vector can be exactly estimated asymptotically if a controller containing a minimal internal model is employed. The effectiveness of our approach has been illustrated by an asymptotic tracking problem of a generalized fourth-order Lorenz system. Copyright © 2009 John Wiley & Sons, Ltd. [source] Tracking control for sampled-data systems with uncertain time-varying sampling intervals and delaysINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 4 2010N. van de Wouw Abstract In this paper, a solution to the approximate tracking problem of sampled-data systems with uncertain, time-varying sampling intervals and delays is presented. Such time-varying sampling intervals and delays can typically occur in the field of networked control systems. The uncertain, time-varying sampling and network delays cause inexact feedforward, which induces a perturbation on the tracking error dynamics, for which a model is presented in this paper. Sufficient conditions for the input-to-state stability (ISS) of the tracking error dynamics with respect to this perturbation are given. Hereto, two analysis approaches are developed: a discrete-time approach and an approach in terms of delay impulsive differential equations. These ISS results provide bounds on the steady-state tracking error as a function of the plant properties, the control design and the network properties. Moreover, it is shown that feedforward preview can significantly improve the tracking performance and an online extremum seeking (nonlinear programming) algorithm is proposed to online estimate the optimal preview time. The results are illustrated on a mechanical motion control example showing the effectiveness of the proposed strategy and providing insight into the differences and commonalities between the two analysis approaches. Copyright © 2009 John Wiley & Sons, Ltd. [source] Time-varying linear controllers for exponential tracking of non-holonomic systems in chained formINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 7 2007Yu-Ping Tian Abstract In this paper, the authors address the tracking problem for non-holonomic systems in chained form with target signals that may exponentially decay to zero. By introducing a time-varying co-ordinate transformation and using the cascade-design approach, smooth time-varying controllers are constructed, which render the tracking-error dynamics globally ,,-exponentially stable. The result shows that the popular condition of persistent excitation or not converging to zero for the reference signals is not necessary even for the globally ,,-exponential tracking of the chained-form system. The effectiveness of the proposed controller is validated by simulation of two benchmark mechanical systems under non-holonomic constraints. Copyright © 2006 John Wiley & Sons, Ltd. [source] On-line estimation and path planning for multiple vehicles in an uncertain environmentINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 8 2004Jarurat Ousingsawat Abstract A unified approach to cooperative target tracking and path planning for multiple vehicles is presented. All vehicles, friendly and adversarial, are assumed to be aircraft. Unlike the typical target tracking problem that uses the linear state and nonlinear output dynamics, a set of aircraft nonlinear dynamics is used in this work. Target state information is estimated in order to integrate into a path planning framework. The objective is to fly from a start point to a goal in a highly dynamic, uncertain environment with multiple friendly and adversarial vehicles, without collision. The estimation architecture proposed is consistent with most path planning methods. Here, the path planning approach is based on evolutionary computation technique which is then combined with a nonlinear extended set membership filter in order to demonstrate a unified approach. A cooperative estimation approach among friendly vehicles is shown to improve speed and routing of the path. Copyright © 2004 John Wiley & Sons, Ltd. [source] Neural Networks Based Control of Mobile Robots: Development and Experimental ValidationJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 10 2003M. L. Corradini The paper proposes a neural networks approach to the solution of the tracking problem for mobile robots. Neural networks based controllers are investigated in order to exploit the nonlinear approximation capabilities of the nets for modeling the kinematic behavior of the vehicle and for reducing unmodeled tracking errors contributions. The training of the nets and the control performances analysis have been done in a real experimental setup. The proposed solutions are implemented on a PC-based control architecture for the real-time control of the LabMate mobile base and are compared with classical kinematic control schemes. Experimental results are satisfactory in terms of tracking errors and computational efforts. © 2003 Wiley Periodicals, Inc. [source] Experimental testing of a discrete-time sliding mode controller for trajectory tracking of a wheeled mobile robot in the presence of skidding effectsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 4 2002M. Letizia Corradini This article addresses the trajectory tracking problem for a wheeled mobile base, considering the presence of disturbances that violate the nonholonomic constraint, and using an approximated discrete-time model for the vehicle. The proposed solution is based on discrete-time sliding mode control, in order to ensure that the controller is both robust and implementable. The asymptotic boundedness of the discrete-time tracking errors is theoretically proved, and experimental results are reported, showing the effectiveness of the proposed control law. © 2002 Wiley Periodicals, Inc. [source] A further result of the nonlinear mixed H2/H, tracking control problem for robotic systemsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 1 2002C. Q. Huang The design objective of a mixed H2/H, control is to find the H2 optimal tracking control law under a prescribed disturbance attenuation level. With the help of the technique of completing the squares, a further result of the mixed H2/H, optimal tracking control problem is presented, by combining it with standard LQ optimal control technique. In this paper, only a nonlinear time-varying Riccati equation is required to solve the problem in the design procedure,instead of two coupled nonlinear time-varying Riccati equations, or two coupled linear algebraic Riccati-Iike equations,with some assumptions made regarding the weighting matrices in the existing results. A closed-form controller for the mixed H2/H, robotic tracking problem is simply constructed with a matrix inequality check. Moreover, it shows that the existing results are the special cases of these results. Finally, detailed comparison is performed by numerical simulation of a two-link robotic manipulator. © 2002 John Wiley & Sons, Inc. [source] Constrained PID tracking control for output PDFs of non-gaussian stochastic system based on LMIs,ASIAN JOURNAL OF CONTROL, Issue 5 2009Yang Yi Abstract This paper presents a new PID tracking control strategy for general non-Gaussian stochastic systems based on a square root B-spline model for the output probability density functions (PDFs). Using the B-spline expansion with modeling errors and the nonlinear weight model with exogenous disturbances, the PDF tracking is transformed to a constrained dynamical tracking control problem for weight vectors. Instead of the non-convex design algorithms, the generalized PID controller structure and the improved convex linear matrix inequality (LMI) algorithms are proposed to fulfil the PDF tracking problem. Meanwhile, in order to enhance robustness, the robust peak-to-peak measure is applied to optimize the tracking performance. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Finite-time tracking control of a nonholonomic mobile robot,ASIAN JOURNAL OF CONTROL, Issue 3 2009Zhao Wang Abstract In this paper, the finite-time tracking problem is investigated for a nonholonomic wheeled mobile robot in a fifth-order dynamic model. We consider the whole tracking error system as a cascaded system. Two continuous global finite-time stabilizing controllers are designed for a second-order subsystem and a third-order subsystem respectively. Then finite-time stability results for cascaded systems are employed to prove that the closed-loop system satisfies the finite-time stability. Thus the closed-loop system can track the reference trajectory in finite-time when the desired velocities satisfy some conditions. In particular, we discuss the control gains selection for the third-order finite-time controller and give sufficient conditions by using Lyapunov and backstepping techniques. Simulation results demonstrate the effectiveness of our method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Robust tracking control design for uncertain robotic systems with persistent bounded disturbancesASIAN JOURNAL OF CONTROL, Issue 4 2008Chung-Shi Tseng Abstract In this study, a robust nonlinear L, - gain tracking control design for uncertain robotic systems is proposed under persistent bounded disturbances. The design objective is that the peak of the tracking error in time domain must be as small as possible under persistent bounded disturbances. Since the nonlinear L, - gain optimal tracking control cannot be solved directly, the nonlinear L, - gain optimal tracking problem is transformed into a nonlinear L, - gain tracking problem by given a prescribed disturbance attenuation level for the L, - gain tracking performance. To guarantee that the L, - gain tracking performance can be achieved for the uncertain robotic systems, a sliding-mode scheme is introduced to eliminate the effect of the parameter uncertainties. By virtue of the skew-symmetric property of the robotic systems, sufficient conditions are developed for solving the robust L, - gain tracking control problems in terms of an algebraic equation instead of a differential equation. The proposed method is simple and the algebraic equation can be solved analytically. Therefore, the proposed robust L, - gain tracking control scheme is suitable for practical control design of uncertain robotic systems. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Robust Tracking Control For A Wheeled Mobile Manipulator With Dual Arms Using Hybrid Sliding-Mode Neural NetworkASIAN JOURNAL OF CONTROL, Issue 4 2007Ching-Chih Tsai ABSTRACT In this paper, a robust tracking controller is proposed for the trajectory tracking problem of a dual-arm wheeled mobile manipulator subject to some modeling uncertainties and external disturbances. Based on backstepping techniques, the design procedure is divided into two levels. In the kinematic level, the auxiliary velocity commands for each subsystem are first presented. A sliding-mode equivalent controller, composed of neural network control, robust scheme and proportional control, is constructed in the dynamic level to deal with the dynamic effect. To deal with inadequate modeling and parameter uncertainties, the neural network controller is used to mimic the sliding-mode equivalent control law; the robust controller is designed to compensate for the approximation error and to incorporate the system dynamics into the sliding manifold. The proportional controller is added to improve the system's transient performance, which may be degraded by the neural network's random initialization. All the parameter adjustment rules for the proposed controller are derived from the Lyapunov stability theory and e-modification such that uniform ultimate boundedness (UUB) can be assured. A comparative simulation study with different controllers is included to illustrate the effectiveness of the proposed method. [source] INPUT-STATE LINEARIZATION OF A ROTARY INVERTED PENDULUMASIAN JOURNAL OF CONTROL, Issue 1 2004Chih-Keng Chen ABSTRACT The aim of this paper is to design a nonlinear controller for the rotary inverted pendulum system using the input-state linearization method. The system is linearized, and the conditions necessary for the system to be linearizable are discussed. The range of the equilibriums of the system is also investigated. Further, after the system is linearized, the linear servo controllers are designed based on the pole-placement scheme to control the output tracking problem. The performance of the controller is studied with different system parameters. The computer simulations demonstrate that the controller can effectively track the reference inputs. [source] A finite element strategy for the solution of interface tracking problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2005C. Devals Abstract A finite element-based numerical strategy for interface tracking is developed for the simulation of two-phase flows. The method is based on the solution of an advection equation for the so-called ,pseudo-concentration' of one of the phases. To obtain an accurate description of the interface, a streamline upwind Petrov,Galerkin (SUPG) scheme is combined with an automatic mesh refinement procedure and a filtering technique, making it possible to generate an oscillation-free pseudo-concentration field. The performance of the proposed approach is successfully tested on four classical two-dimensional benchmark problems: the advection skew to the mesh, the transport of a square shape in a constant velocity flow field, the transport of a cut-out cylinder in a rotating flow field and the transport of a disc in a shear flow. Copyright © 2005 John Wiley & Sons, Ltd. [source] Nonlinear Laguerre,Volterra observer-controller and its application to process controlINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 4 2010Hai-Tao Zhang Abstract By expanding each kernel using the orthonormal Laguerre series, a Volterra functional series is used to represent the input/output relation of a nonlinear dynamic system. With the feedback of the modeling error, we design a novel nonlinear state observer, based on which an output feedback controller is derived for both the stabilization and tracking problems. The stability of the closed-loop system is analyzed theoretically. The algorithm is effectively applied on the continuous stirring tank reactor and chemical reactor temperature control system. Copyright © 2009 John Wiley & Sons, Ltd. [source] Dynamic Feedback Control of XYnR, Planar Robots with n Rotational Passive JointsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2003Stefano Iannitti We consider the problem of trajectory planning and control for an XYnR, Planar robot with the first two joints (rotational or prismatic) actuated and n rotational passive joints, moving both in the presence and the absence of gravity. Under the assumption that each passive link is attached at the center of percussion of the previous passive link, dynamics of the system can be expressed through the behavior of n special points of the plane. These points are called link-related acceleration points (LRAP) since their instantaneous acceleration is oriented as the axis of the related passive links. Moreover, LRAP dynamics present a backward recursive form which can be exploited to recursively design a dynamic feedback that completely linearizes the system equations. We use this approach to solve trajectory planning and tracking problems and report simulation results obtained for an RR2R, robot having the first two rotational joints actuated. © 2003 Wiley Periodicals, Inc. [source] | ||||||||||