Showing papers on "Variable structure control published in 2001"
TL;DR: Adaptive robust control laws are developed for MIMO nonlinear systems transformable to two semi-strict feedback forms that allow coupling and appearance of parametric uncertainties in the input matrix of each layer.
327 citations
TL;DR: In this article, two globally stable control algorithms for robust stabilization of spacecraft in the presence of control input saturation, parametric uncertainty, and external disturbances are proposed and a detailed stability analysis for the resulting closed-loop system is provided.
Abstract: In this paper we propose two globally stable control algorithms for robust stabilization of spacecraft in the presence of control input saturation, parametric uncertainty, and external disturbances. The control algorithms are based on variable structure control design and have the following properties: 1 ) fast and accurate response in thepresenceofbounded external disturbancesand parametricuncertainty;2 )explicit accounting forcontrol input saturation; 3 ) computational simplicity and straightforward tuning. We include a detailed stability analysis for the resulting closed-loop system. The stability proof is based on a Lyapunov-like analysis and the properties of the quaternion representation of spacecraft dynamics. It is also shown that an adaptive version of the proposed controller results in substantially simpler stability analysis and improved overall response. We also include numerical simulations to illustrate the spacecraft performance obtained using the proposed controllers.
323 citations
TL;DR: It is proved that the proposed adaptive scheme can achieve asymptotically stable tracking of a reference input with a guarantee of the bounded system signals and the steady error is also alleviated.
307 citations
01 Nov 2001
TL;DR: This paper discusses two control approaches for the problems of swingup and balance, namely, feedback linearization and passivity based control and shows that the Reaction Wheel Pendulum is locally feedback linearizable by a local diffeomorphism in state space and nonlinear feedback.
Abstract: In this paper we introduce the Reaction Wheel Pendulum, a novel mechanical system consisting of a physical pendulum with a rotating bob. This system has several attractive features both from a pedagogical standpoint and from a research standpoint. From a pedagogical standpoint, the dynamics are the simplest among the various pendulum experiments available so that the system can be introduced to students earlier in their education. At the same time, the system is nonlinear and underactuated so that it can be used as a benchmark experiment to study recent advanced methodologies in nonlinear control, such as feedback linearization, passivity methods, backstepping and hybrid control. In this paper we discuss two control approaches for the problems of swingup and balance, namely, feedback linearization and passivity based control. We first show that the system is locally feedback linearizable by a local diffeomorphism in state space and nonlinear feedback. We compare the feedback linearization control with a linear pole-placement control for the problem of balancing the pendulum about the inverted position. For the swingup problem we discuss an energy approach based on collocated partial feedback linearization, and passivity of the resulting zero dynamics. A hybrid/switching control strategy is used to switch between the swingup and the balance control. Experimental results are presented.
264 citations
TL;DR: In this paper, the Reaction Wheel Pendulum, a pendulum with a rotating bob, is used to balance the pendulum about the inverted position, and a hybrid/switching control strategy is employed to switch between swingup and balance control.
257 citations
TL;DR: The singularly perturbed relay control systems (SPRCS) as mathematical models of chattering in the small neighborhood of the switching surface in sliding mode systems are examined and it is shown that the slow motions in such SPRCS are approximately described by equations derived from equations for the slow variables of SPRCS by averaging along fast periodic motions.
Abstract: The singularly perturbed relay control systems (SPRCS) as mathematical models of chattering in the small neighborhood of the switching surface in sliding mode systems are examined. Sufficient conditions for existence and stability of fast periodic solutions to the SPRCS are found. It is shown that the slow motions in such SPRCS are approximately described by equations derived from equations for the slow variables of SPRCS by averaging along fast periodic motions. It is shown that In the general case, when the equations of a plant contain relay control nonlinearly, the averaged equations do not coincide with the equivalent control equations or with the Filippov's definition (1988) for the sliding motions in the reduced system; however, in the linear case, they coincide.
224 citations
TL;DR: In this article, a variable structure control (VSC) based guidance law was proposed, where the acceleration command input is determined considering the target acceleration as an uncertainty, and the proposed guidance law uses only the information for the estimated target acceleration bound.
Abstract: The missile guidance law utilizing variable structure control is proposed. The acceleration command input is determined considering the target acceleration as an uncertainty. The proposed guidance law uses only the information for the target acceleration bound; therefore, the precise measuring of target acceleration during the maneuver is not required, and the robustness to the target maneuver is achieved. It is also shown that the proposed guidance law can be classie ed into the augmented true proportional navigation or the augmented realistic true proportional navigation guidance law. Numerical simulations show that the proposed guidance law yields better performance compared to existing guidance laws. ROPORTIONAL navigation guidance (PNG) was e rst developed during the 1950s, and during the 1970s and 1980s various PNG laws such as pure proportional navigation (PPN), true proportional navigation (TPN), the optimal guidance law (OGL), generalized TPN (GTPN), and realistic TPN (RTPN) have been developed. 1;2 Lots of studies have been performed to obtain analytical solutions as well as to analyze the capture regions of the guidance laws. With the development of accurate avionic sensors, augmented proportional navigation (APN) and the predictive guidance law (PGL) utilizing the information about target acceleration were also proposed. By analyzing the various guidance laws, the characteristics of the guidance laws, capture regions, and pursuing performance were compared. 1;2
187 citations
TL;DR: In this article, the double integrator plant is considered, which is one of the most fundamental systems in control applications, representing single degree-of-freedom translational and rotational motion.
Abstract: We deal with a form of controller evaluation that may be called naive control In naive control, a control algorithm derived under nominal (or ideal) conditions is evaluated by analytical or numerical means under off-nominal (or nonideal) conditions that were not assumed in the formal synthesis procedure Under such nonideal conditions, the controller may or may not perform well This approach is distinct from robust control, which seeks to accommodate off-nominal perturbations in the synthesis procedure We consider the double integrator plant, which is one of the most fundamental systems in control applications, representing single degree-of-freedom translational and rotational motion Applications of the double integrator include low-friction, free rigid-body motion, such as single-axis spacecraft rotation and rotary crane motion The double integrator plant considered includes a saturation nonlinearity on the control input
156 citations
TL;DR: Because the tracking performance by a forward control cannot be guaranteed as the system is subject to uncertainties, a discrete-time variable-structure control is synthesized to improve the performance.
Abstract: The so-called piezomechanics contain three parts: piezoelectric translator, carriage mechanism, and control system. It is well known that piezomechanics have three drawbacks: (1) it should only be loaded axially; (2) it contains a hysteresis feature; and (3) its expansion is dependent on temperature. The first drawback is tackled by the design of the carriage mechanism. This paper focuses on dealing with the second and third drawbacks by using an intelligent variable-structure control. First, a neural network is employed to learn the dynamics of the piezomechanism. Second, a novel forward control based on the learned model is employed to achieve an acceptable tracking result. Because the tracking performance by a forward control cannot be guaranteed as the system is subject to uncertainties, a discrete-time variable-structure control is synthesized to improve the performance. No state estimator is required for the proposed control. The stability of the overall system is verified via the Lyapunov analysis. Experiments are also presented to confirm the effectiveness of the proposed control.
136 citations
TL;DR: A global adaptive output-feedback control scheme, which does not require a priori knowledge of high-frequency gain sign, is proposed for general nonlinear systems in output-feedingback form.
Abstract: A global adaptive output-feedback control scheme, which does not require a priori knowledge of high-frequency gain sign, is proposed for general nonlinear systems in output-feedback form. Unlike in Ding (1998), the removal of a priori knowledge of the high-frequency gain sign is not at the price of making growth restrictions on system nonlinearities, and furthermore, only the minimal number of parameters needs to be updated.
124 citations
25 Jun 2001
TL;DR: A new sliding mode controller for semi-active suspension systems with Magnetorheological (MR) dampers which have undesirable nonlinear properties is presented, which is highly possible to maintain the sliding mode and achieve high robustness against model uncertainties and disturbances.
Abstract: This paper presents a new sliding mode controller for semi-active suspension systems with Magnetorheological (MR) dampers which have undesirable nonlinear properties. In the proposed controller, a desired semi-active suspension system is chosen as the reference model to be followed, and the control low is determined so that an asymptotically stable sliding mode will occur in the error dynamics between the plant and the reference model states. The advantages of the proposed controller are: (1) measurement of the-damper force is not required, (2) the reference model specifies the desired performance considering the passivity constraint of the damper, (3) it is highly possible to maintain the sliding mode and achieve high robustness against model uncertainties and disturbances. Numerical simulations illustrate the effectiveness of the controller.
04 Dec 2001
TL;DR: In this paper, the authors consider the problem of controlling the vertical motion of a nonlinear model of a helicopter to a reference signal, while stabilizing the lateral and horizontal position and maintaining a constant attitude.
Abstract: We consider the problem of controlling the vertical motion of a nonlinear model of a helicopter to a reference signal, while stabilizing the lateral and horizontal position and maintaining a constant attitude. The reference to be tracked is given by a sum of a constant and a fixed number of sinusoidal signals, and it is assumed not to be available to the controller. This represents a possible situation in which the helicopter is required to synchronize its vertical motion with that of an oscillating platform, as the one given by a sea carrier subject to wave-induced oscillations. We design a nonlinear controller which combines results on nonlinear adaptive output regulations and robust stabilization of systems in feedforward form by means of saturated controls. Simulation results show the effectiveness of the method and its ability to cope with large uncertainties on the plant, the actuator model and the exogenous reference signal.
TL;DR: A scheme is proposed for control of multi-body, multi-input and multi-output nonlinear systems with joint backlash, flexibility and damping, represented by a gun turret-barrel model which consists of two subsystems: two motors driving two loads coupled by nonlinear dynamics.
TL;DR: This paper presents a synthesis of a nonlinear switching control of a rotational electropneumatic servo drive using a sliding mode approach and shows that the integral discontinuous control provides best results especially for a steady-state error cancellation.
Abstract: This paper presents a synthesis of a nonlinear switching control of a rotational electropneumatic servo drive using a sliding mode approach. A nonlinear sliding mode control law is applied to the system under consideration. First, the model of the electropneumatic servo drive is developed. This model is nonlinear with respect to both the state variables and the control input. It is transformed to be linear with respect to a new control variable and a coordinate transformation is then related to make possible the implementation of the nonlinear discontinuous controller. Two sliding mode controllers are synthesized with and without an integral term in the switching surface. The sliding regimes are particularly pointed out and their stability analyzed to show that the integral discontinuous control provides best results especially for a steady-state error cancellation. Practical considerations are proposed for choosing the control parameters. Finally, the experimental results are presented and discussed.
TL;DR: A delay-independent adaptive variable structure controller to drive the states of system to zero is developed by applying the Lyapunov stability theorem and the globally asymptotic stability is guaranteed for the proposed control scheme under certain conditions.
Abstract: The problem of stabilizing a class of perturbed linear dynamic systems with time-varying state delay is investigated in this paper. By applying the Lyapunov stability theorem, we develop a delay-independent adaptive variable structure controller to drive the states of system to zero. Based on the variable structure control (VSC) technique, the proposed controller can drive the system into a pre-specified sliding hyperplane to obtain the desired dynamic performance. Once the dynamics of system reach the sliding plane, the proposed controlled system is insensitive to perturbations. The use of adaptive technique is to overcome the unknown upper bound of perturbations so that the reaching condition (or sliding condition) can be satisfied. Furthermore, the globally asymptotic stability is guaranteed for the proposed control scheme under certain conditions. Finally, an example is given to illustrate the feasibility of the proposed control methodology.
21 May 2001
TL;DR: This paper modify the previous controller to have a sliding surface for the slave include an impedance model, and since the nonlinear gain of the sliding controller is independent of the time delay, it is not necessary to measure or estimate the timedelay to implement the controller.
Abstract: In the previous works, we have proposed new control schemes based on the sliding mode control and impedance control in order to cope with varying time delays. However, the previous controller needs local compliance to reduce contact forces between the slave and environment. In this paper, we modify the previous one to have a sliding surface for the slave include an impedance model. Since the nonlinear gain of the sliding controller is independent of the time delay as in the previous proposed controllers, it is not necessary to measure or estimate the time delay to implement the controller. The validity of the proposed control scheme is demonstrated by experiments with a 1-DOF master/slave system connected through the Internet.
05 Sep 2001
TL;DR: In this article, the authors considered the regulation control problem for a two-degree-of-freedom (2-DOF) underactuated overhead crane system and designed several controllers that asymptotically regulate the gantry position and payload position.
Abstract: We consider the regulation control problem for a two-degree-of-freedom (2-DOF), underactuated overhead crane system. Inspired by recently designed passivity-based controllers for underactuated systems, we design several controllers that asymptotically regulate the gantry position and payload position. Specifically, utilizing LaSalle's invariance set theorem, we first illustrate how a simple proportional-derivative (PD) controller can be utilized to asymptotically regulate the overhead crane system. Motivated by the desire to achieve improved transient performance, we then design a two nonlinear controllers that increase the coupling between the gantry position and payload position.
01 Jan 2001
TL;DR: In this paper, the authors proposed a passivity approach for identification of continuous time nonlinear systems, which can be used to model and control nonlinear control systems in open-loop and closed-loop operation.
Abstract: Control of a reduced size model of US navy crane using only motor position sensors.- Algorithms for identification of continuous time nonlinear systems: a passivity approach. Part I: Identification in open-loop operation Part II: Identification in llosed-loop operation.- Flatness-based boundary control of a nonlinear parabolic equation modelling a tubular reactor.- Dynamic feedback transformations of controllable linear time-varying systems.- Asymptotic controllability implies continuous-discrete time feedback stabilizability.- Stabilisation of nonlinear systems by discontinuous dynamic state feedback.- On the stabilization of a class of uncertain systems by bounded control.- Adaptive nonlinear excitation control of synchronous generators with unknown mechanical power.- Nonlinear observers of time derivatives from noisy measurements of periodic signals.- Hamiltonian representation of distributed parameter systems with boundary energy flow.- Differentiable lyapunov function and center manifold theory.- Controlling self-similar traffic and shaping techniques.- Diffusive representation for pseudo-differentially damped nonlinear systems.- Euler's discretization and dynamic equivalence of nonlinear control systems.- Singular systems in dimension 3: Cuspidal case and tangent elliptic flat case.- Flatness of nonlinear control systems and exterior differential systems.- Motion planning for heavy chain systems.- Control of an industrial polymerization reactor using flatness.- Controllability of nonlinear multidimensional control systems.- Stabilization of a series DC motor by dynamic output feedback.- Stabilization of nonlinear systems via forwarding mod{L g V}.- A robust globally asymptotically stabilizing feedback: The example of the artstein's circles.- Robust stabilization for the nonlinear benchmark problem (TORA) using neural nets and evolution strategies.- On convexity in stabilization of nonlinear systems.- Extended goursat normal form: a geometric characterization.- Trajectory tracking for ?-flat nonlinear delay systems with a motor example.- Neuro-genetic robust regulation design for nonlinear parameter dependent systems.- Stability criteria for time-periodic systems via high-order averaging techniques.- Control of nonlinear descriptor systems, a computer algebra based approach.- Vibrational control of singularly perturbed systems.- Recent advances in output regulation of nonlinear systems.- Sliding mode control of the prismatic-prismatic-revolute mobile robot with a flexible joint.- The ISS philosophy as a unifying framework for stability-like behavior.- Control design of a crane for offshore lifting operations.- New theories of set-valued differentials and new versions of the maximum principle of optimal control theory.- Transforming a single-input nonlinear system to a strict feedforward form via feedback.- Extended active-passive decomposition of chaotic systems with application to the modelling and control of synchronous motors.- On canonical decomposition of nonlinear dynamic systems.- New developments in dynamical adaptive backstepping control.
TL;DR: A suitable iterative learning procedure, that leads to the asymptotic reduction of the boundary layer to O(T^3) is proposed and results are reported.
01 Jun 2001
TL;DR: This paper deals with modern control systems technology that is frequently applied to power conversion systems and points out how a wide variety of control techniques can be applied to enhance the controller performance and bandwidth in power electronics.
Abstract: This paper deals with modern control systems technology that is frequently applied to power conversion systems. The discussion goes far beyond the basic level of switch control in switching regulators. System-level control issues are important in expanding the market base of power electronics. Improvement in system performance involves not only the use of advanced control techniques, but also the integration of several converters or converter systems into a larger system. A fully controlled rectifier and an induction motor drive system are presented as typical applications to illustrate the use of many techniques for controlling power converters. The paper then points out how a wide variety of control techniques can be applied to enhance the controller performance and bandwidth in power electronics. These techniques include observers and adaptive control, nonlinear control, sliding and dead-beat control, and intelligent control. Finally, the paper points out how power electronic system performance can be enhanced through the use of condition monitoring and diagnostics.
TL;DR: In this article, the class of systems for which a suitable variable structure control algorithm ensures finite-time global convergence to the sliding manifold is identified, based on the stabilization of uncertain second-order nonlinear systems with incomplete state availability.
Abstract: The second order sliding mode control of uncertain dynamical systems can be expressed in terms of the stabilization of uncertain second-order non-linear systems with incomplete state availability. The existence of the solution strictly depends on the assumptions made on the uncertainties, and global results are not always attainable. In this paper the class of systems for which a suitable variable structure control algorithm ensures finite time global convergence to the sliding manifold is identified. Simulation results highlight the effectiveness of the proposed method.
TL;DR: An observer-based inverse dynamics control strategy that results in small tip-position tracking errors while maintaining robust closed-loop performance for a class of multi-link structurally flexible manipulators.
TL;DR: In this paper, passivity-based adaptive and non-adaptive chattering-free sliding mode controllers are proposed assuming that the upper bound of the norm of the derivative of the sliding surface is available, a weaker and easy to implement assumption in comparison to those of 2-smc and dsmc.
Abstract: Second-order sliding mode control (2-smc) and dynamic sliding mode control (dsmc) eliminate the disturbing characteristic of chattering in static sliding mode control under the assumption that the derivative of the sliding surface is available or complex inequalities at the acceleration level can be constructed. In this paper, passivity-based adaptive and non-adaptive chattering-free sliding mode controllers are proposed assuming that the upper bound of the norm of the derivative of the sliding surface is available, a weaker and easy to implement assumption in comparison to those of 2-smc and dsmc. The closed-loop system accounts explicitly for the invariance condition without reaching phase, and therefore for a desired transient response with global exponential convergence of tracking errors. Preliminary experiments are presented. Copyright © 2001 John Wiley & Sons, Ltd.
TL;DR: In this article, a structure response control approach which uses controlled interactions between two parallel structures (a primary structure and an auxiliary structure) to reduce the seismic response of the primary structure (P-structure) during earthquake excitation, is proposed.
TL;DR: The approach presented introduces a suitable commutation logic (based on an online simple predictor) that prevents an uncontrollable growth of the uncertainties and the global convergence of the state trajectory to the designed sliding manifold is ensured.
Abstract: Second-order sliding-mode control (2-SMC) algorithms are analyzed to assess their global convergence properties. While standard first-order sliding-mode control (1-SMC) algorithms derive their effectiveness from the global solution of the well known "reaching condition" ss/spl dot//spl les/-k/sup 2/|s| (s=0 being the actual sliding manifold), 2-SMC is based on more complex differential inequalities, for which a global solution could not exist. The approach presented introduces a suitable commutation logic (based on an online simple predictor) that prevents an uncontrollable growth of the uncertainties. Due to this new commutation logic, the global convergence of the state trajectory to the designed sliding manifold is ensured.
TL;DR: In this paper, the sliding mode control of a permanent magnet (PM) stepper motor is addressed from the perspective of differentially flat systems, which naturally allow for de-coupled linearization directly leading to static and dynamic discontinuous feedback control alternatives.
Abstract: In this paper, the sliding mode control of a permanent magnet (PM) stepper motor is addressed from the perspective of differentially flat systems. Flat systems naturally allow for de-coupled linearization directly leading to static and dynamic discontinuous feedback control alternatives. Implementation results of the proposed sliding mode control schemes on an experimental set-up are given to illustrate the developments.
TL;DR: A modified variable structure controllers is derived to guarantee the existence of the sliding mode by using output feedback only and the stability of the equivalent reduced-order system in the slidingmode is assured under certain conditions.
TL;DR: In this paper, a variable structure controller for a distributed-parameter flexible beam is proposed, which can stabilize the system exponentially and the converging speed can be set by the designer as desired.
Abstract: In this article, regulation of a distributed-parameter flexible beam is considered using variable structure control techniques. The proposed controller can stabilize the system exponentially and the converging speed can be set by the designer as desired. Different from existing variable structure controllers for flexible robots in the literature, the controller presented here is designed directly for the partial differential equations governing the motion of the distributed-parameter system. Thus, exponential stability holds for the original distributed-parameter system. Numerical simulations are also provided to verify the effectiveness of the approach presented. © 2001 John Wiley & Sons, Inc.
TL;DR: This paper focuses on the design of an output feedback sliding mode regulator able to achieve the asymptotic tracking of a reference trajectory for nonlinear systems.
01 Feb 2001
TL;DR: A generalized projection update law, which generalizes the projection algorithm modification and the switching-sigma adaptive law, is used to tune the adjustable parameters for preventing parameter drift and confining states of the system to the specified regions.
Abstract: In this paper, a robust adaptive fuzzy-neural control scheme for nonlinear dynamical systems is proposed to attenuate the effects caused by unmodeled dynamics, disturbance, and modeling errors. A generalized projection update law, which generalizes the projection algorithm modification and the switching-/spl sigma/ adaptive law, is used to tune the adjustable parameters for preventing parameter drift and confining states of the system to the specified regions. Moreover, a variable structure control method is incorporated into the control law so that the derived controller is robust with respect to unmodeled dynamics, disturbances, and modeling errors. To demonstrate the effectiveness of the proposed method, several examples are illustrated in this paper.