Showing papers on "Sliding mode control published in 2010"
TL;DR: A barrier Lyapunov function (BLF) is introduced to address two open and challenging problems in the neuro-control area: for any initial compact set, how to determine a priori the compact superset on which NN approximation is valid; and how to ensure that the arguments of the unknown functions remain within the specified compact supersets.
Abstract: In this brief, adaptive neural control is presented for a class of output feedback nonlinear systems in the presence of unknown functions. The unknown functions are handled via on-line neural network (NN) control using only output measurements. A barrier Lyapunov function (BLF) is introduced to address two open and challenging problems in the neuro-control area: 1) for any initial compact set, how to determine a priori the compact superset, on which NN approximation is valid; and 2) how to ensure that the arguments of the unknown functions remain within the specified compact superset. By ensuring boundedness of the BLF, we actively constrain the argument of the unknown functions to remain within a compact superset such that the NN approximation conditions hold. The semiglobal boundedness of all closed-loop signals is ensured, and the tracking error converges to a neighborhood of zero. Simulation results demonstrate the effectiveness of the proposed approach.
818 citations
TL;DR: The goal is to obtain a robust sliding mode adaptive-gain control law with respect to uncertainties and perturbations without the knowledge of uncertainties/perturbations bound (only the boundness feature is known).
Abstract: This article proposes new methodologies for the design of adaptive sliding mode control. The goal is to obtain a robust sliding mode adaptive-gain control law with respect to uncertainties and perturbations without the knowledge of uncertainties/perturbations bound (only the boundness feature is known). The proposed approaches consist in having a dynamical adaptive control gain that establishes a sliding mode in finite time. Gain dynamics also ensures that there is no overestimation of the gain with respect to the real a priori unknown value of uncertainties. The efficacy of both proposed algorithms is confirmed on a tutorial example and while controlling an electropneumatic actuator.
676 citations
TL;DR: A new necessary and sufficient condition is proposed in terms of strict linear matrix inequality (LMI), which guarantees the stochastic admissibility of the unforced Markovian jump singular system.
Abstract: This paper is concerned with the state estimation and sliding-mode control problems for continuous-time Markovian jump singular systems with unmeasured states. Firstly, a new necessary and sufficient condition is proposed in terms of strict linear matrix inequality (LMI), which guarantees the stochastic admissibility of the unforced Markovian jump singular system. Then, the sliding-mode control problem is considered by designing an integral sliding surface function. An observer is designed to estimate the system states, and a sliding-mode control scheme is synthesized for the reaching motion based on the state estimates. It is shown that the sliding mode in the estimation space can be attained in a finite time. Some conditions for the stochastic admissibility of the overall closed-loop system are derived. Finally, a numerical example is provided to illustrate the effectiveness of the proposed theory.
596 citations
TL;DR: A nonlinear sliding-mode speed-control scheme for interior permanent-magnet synchronous motor drives incorporating the maximum-torque-per-ampere trajectory is proposed, capable of exhibiting high dynamic and steady-state performances over a wide speed range.
Abstract: This paper proposes a nonlinear sliding-mode speed-control scheme for interior permanent-magnet synchronous motor (IPMSM) drives incorporating the maximum-torque-per-ampere trajectory. The drive uses an adaptive sliding-mode observer (SMO) for rotor-speed estimation. The global asymptotic stabilities of both the controller and observer are guaranteed by Lyapunov stability analysis. The very low speed and standstill performance of the drive is further enhanced by combining high-frequency signal injection with the SMO. Hence, the sensorless drive is capable of exhibiting high dynamic and steady-state performances over a wide speed range. Experimental results confirm the effectiveness of the proposed method.
354 citations
TL;DR: Experimental results demonstrate that the performance of proposed controller is superior to that of conventional SMCPE in both set-point regulation and motion tracking control and validates the feasibility of the proposed controller in the field of micro/nano scale manipulation as well.
Abstract: This paper proposes an improved sliding mode control with perturbation estimation (SMCPE) featuring a PID-type sliding surface and adaptive gains for the motion tracking control of a micromanipulator system with piezoelectric actuation One advantage of the proposed controller lies in that its implementation only requires the online estimation of perturbation and control gains without acquiring the knowledge of bounds on system uncertainties The dynamic model of the system with Bouc-Wen hysteresis is established and identified through particle swarm optimization (PSO) approach, and the controller is designed based on Lyapunov stability analysis A high-gain observer is adopted to estimate the full state from the only measurable position information Experimental results demonstrate that the performance of proposed controller is superior to that of conventional SMCPE in both set-point regulation and motion tracking control Moreover, a submicron accuracy tracking and contouring is achieved by the micromanipulator with dominant hysteresis compensated for a low magnitude level, which validates the feasibility of the proposed controller in the field of micro/nano scale manipulation as well
337 citations
TL;DR: By introducing some specified matrices, a new sufficient condition is proposed in terms of strict linear matrix inequality (LMI), which guarantees the stochastic stability of the sliding mode dynamics.
283 citations
TL;DR: This paper is devoted to design adaptive sliding-mode controllers for the Takagi-Sugeno (T--S) fuzzy system with mismatched uncertainties and exogenous disturbances with linear-matrix inequalities.
Abstract: This paper is devoted to design adaptive sliding-mode controllers for the Takagi-Sugeno (T--S) fuzzy system with mismatched uncertainties and exogenous disturbances. The uncertainties in state matrices are mismatched and norm-bounded, while the exogenous disturbances are assumed to be bounded with an unknown bound, which is estimated by a simple and effective adaptive approach. Both state- and static-output-feedback sliding-mode-control problems are considered. In terms of linear-matrix inequalities (LMIs), both sliding surfaces and sliding-mode controllers can be easily obtained via a convex optimization technique. Finally, two simulation examples and a real experiment are utilized to illustrate the applicability and effectiveness of the design procedures proposed in this paper.
281 citations
TL;DR: In this paper, a direct active and reactive power control (DPC) for grid-connected doubly fed induction generator (DFIG)-based wind turbine systems is proposed, which employs a nonlinear sliding-mode control scheme to directly calculate the required rotor control voltage so as to eliminate the instantaneous errors of reactive powers without involving any synchronous coordinate transformations.
Abstract: This paper presents a new direct active and reactive power control (DPC) of grid-connected doubly fed induction generator (DFIG)-based wind turbine systems. The proposed DPC strategy employs a nonlinear sliding-mode control scheme to directly calculate the required rotor control voltage so as to eliminate the instantaneous errors of active and reactive powers without involving any synchronous coordinate transformations. Thus, no extra current control loops are required, thereby simplifying the system design and enhancing the transient performance. Constant converter switching frequency is achieved by using space vector modulation, which eases the designs of the power converter and the ac harmonic filter. Simulation results on a 2-MW grid-connected DFIG system are provided and compared with those of classic voltage-oriented vector control (VC) and conventional lookup table (LUT) DPC. The proposed DPC provides enhanced transient performance similar to the LUT DPC and keeps the steady-state harmonic spectra at the same level as the VC strategy.
281 citations
TL;DR: Two sliding-mode-control (SMC) methods are proposed for the MWIP systems, both of which are capable of handling both parameter uncertainties and external disturbances, and the effectiveness of the proposed methods is finally confirmed by the numerical simulations.
Abstract: There has been increasing interest in a type of underactuated mechanical systems, mobile-wheeled inverted-pendulum (MWIP) models, which are widely used in the field of autonomous robotics and intelligent vehicles. Robust-velocity-tracking problem of the MWIP systems is investigated in this study. In the velocity-control problem, model uncertainties accompany uncertain equilibriums, which make the controller design become more difficult. Two sliding-mode-control (SMC) methods are proposed for the systems, both of which are capable of handling both parameter uncertainties and external disturbances. The asymptotical stabilities of the corresponding closed-loop systems are achieved through the selection of sliding-surface parameters, which are based on some rules. There is still a steady tracking error when the first SMC controller is used. By assuming a novel sliding surface, the second SMC controller is designed to solve this problem. The effectiveness of the proposed methods is finally confirmed by the numerical simulations.
219 citations
TL;DR: A new speed-estimation adaptation law is derived using Lyapunov theory to ensure estimation stability, as well as fast error dynamics in both modes of operations.
Abstract: In this paper, two novel adaptation schemes are proposed to replace the classical PI controller used in model reference adaptive speed-estimation schemes that are based on rotor flux. The first proposed adaptation scheme is based on sliding-mode theory. A new speed-estimation adaptation law is derived using Lyapunov theory to ensure estimation stability, as well as fast error dynamics. The other adaptation mechanism is based on fuzzy-logic strategy. A detailed experimental comparison between the new and conventional schemes is carried out in both open- and closed-loop sensorless modes of operation when a vector control drive is working at very low speed. Superior performance has been obtained using the new sliding-mode and fuzzy-logic adaptation mechanisms in both modes of operations.
209 citations
TL;DR: The application of fuzzy logic and sliding mode controls are presented in order to obtain a high-accuracy positioning of a 6PIM rotor in both healthy and faulted modes.
Abstract: The faulted mode of a six-phase induction machine (6PIM) denotes that the motor is working with one or more missing phases. This situation leads to torque oscillations and poor tracking behavior. Therefore, the design of a suitable robust control is a challenging task. In this way, this paper presents the application of fuzzy logic and sliding mode controls in order to obtain a high-accuracy positioning of a 6PIM rotor in both healthy and faulted modes. The two control strategies are completely different from a theoretical point of view, but the final objectives are to remove the drawbacks of the specific fault on interest. The experimental results are obtained on a dedicated setup based on a 6PIM coupled with a variable mechanical load and for which up to three phases can be removed.
01 Dec 2010
TL;DR: The proposed Lyapunov-based approach consists in using dynamically adapted control gains that ensure the establishment, in a finite time, of a second order sliding mode.
Abstract: A novel super-twisting adaptive sliding mode controller is proposed. A drift uncertain term is assumed to be bounded with unknown boundary. The proposed Lyapunov-based approach consists in using dynamically adapted control gains that ensure the establishment, in a finite time, of a second order sliding mode. Finite convergence time is estimated. A numerical example confirms the efficacy of the proposed adaptive super-twisting control.
TL;DR: To reduce the chattering phenomenon in sliding mode control (SMC), a fuzzy logic controller is used to replace the discontinuity in the signum function at the reaching phase in the sliding mode controller.
TL;DR: It is shown that torsional oscillations can be successfully suppressed in the proposed control structure, using only one basic feedback from the motor speed given by the proposed speed estimator.
Abstract: In this paper, the concept of a model reference adaptive control of a sensorless induction motor (IM) drive with elastic joint is proposed. An adaptive speed controller uses fuzzy neural network equipped with an additional option for online tuning of its chosen parameters. A sliding-mode neuro-fuzzy controller is used as the speed controller, whose connective weights are trained online according to the error between the estimated motor speed and the speed given by the reference model. The speed of the vector-controlled IM is estimated using the MRASCC rotor speed and a flux estimator. Such a control structure is proposed to damp torsional vibrations in a two-mass system in an effective way. It is shown that torsional oscillations can be successfully suppressed in the proposed control structure, using only one basic feedback from the motor speed given by the proposed speed estimator. Simulation results are verified by experimental tests over a wide range of motor speed and drive parameter changes.
TL;DR: The designed control scheme is robust against the system’s uncertainty and guarantees the property of asymptotical stability in the presence of an external disturbance.
Abstract: This paper deals with designing a sliding mode controller (SMC) for a fractional-order chaotic financial system. Using the sliding mode control technique, a sliding surface is determined. The sliding mode control law is derived to make the states of the fractional-order financial system asymptotically stable. The designed control scheme is robust against the system’s uncertainty and guarantees the property of asymptotical stability in the presence of an external disturbance. An illustrative simulation result is given to demonstrate the effectiveness of the proposed sliding mode control design.
TL;DR: A robust adaptive fault-tolerant control approach to attitude tracking of flexible spacecraft is proposed for use in situations when there are reaction wheel/actuator failures, persistent bounded disturbances and unknown inertia parameter uncertainties.
Abstract: In this paper, a robust adaptive fault-tolerant control approach to attitude tracking of flexible spacecraft is proposed for use in situations when there are reaction wheel/actuator failures, persistent bounded disturbances and unknown inertia parameter uncertainties. The controller is designed based on an adaptive backstepping sliding mode control scheme, and a sufficient condition under which this control law can render the system semi-globally input-to-state stable is also provided such that the closed-loop system is robust with respect to any disturbance within a quantifiable restriction on the amplitude, as well as the set of initial conditions, if the control gains are designed appropriately. Moreover, in the design, the control law does not need a fault detection and isolation mechanism even if the failure time instants, patterns and values on actuator failures are also unknown for the designers, as motivated from a practical spacecraft control application. In addition to detailed derivations of the new controller design and a rigorous sketch of all the associated stability and attitude error convergence proofs, illustrative simulation results of an application to flexible spacecraft show that high precise attitude control and vibration suppression are successfully achieved using various scenarios of controlling effective failures.
TL;DR: In this paper, an approach for tracking control of robot manipulators is presented, which incorporates the approximately known inverse dynamic model output as a model-base portion of the controller; an estimated uncertainty term to compensate for the unmodeled dynamics, external disturbances, and time-varying parameters; and a decentralized PID controller as a feedback portion to enhance closed-loop stability and account for the estimation error of uncertainties.
TL;DR: It is demonstrated that the proposed 2-SMC system improves the performance of the closed-loop system with better tracking specifications in the case of external disturbances, better behavior of the output and faster convergence of the sliding surface while maintaining the stability.
Abstract: In this article, a second-order sliding mode control (2-SMC) is proposed for second-order uncertain plants using equivalent control approach to improve the performance of control systems. A Proportional + Integral + Derivative (PID) sliding surface is used for the sliding mode. The sliding mode control law is derived using direct Lyapunov stability approach and asymptotic stability is proved theoretically. The performance of the closed-loop system is analysed through an experimental application to an electromechanical plant to show the feasibility and effectiveness of the proposed second-order sliding mode control and factors involved in the design. The second-order plant parameters are experimentally determined using input-output measured data. The results of the experimental application are presented to make a quantitative comparison with the traditional (first-order) sliding mode control (SMC) and PID control. It is demonstrated that the proposed 2-SMC system improves the performance of the closed-loop system with better tracking specifications in the case of external disturbances, better behavior of the output and faster convergence of the sliding surface while maintaining the stability.
23 Dec 2010
TL;DR: In this article, the sliding mode approach is used to control a quadrotor unmanned aerial vehicle (UAV) in the presence of external disturbance and actuator fault, and the proposed control structure has the advantage of disturbance rejection in the fault-free condition.
Abstract: In this paper, the sliding mode approach is used to control of a quadrotor unmanned aerial vehicle (UAV) in the presence of external disturbance and actuator fault. Fault detection unit can detect the actuator fault using a state estimator. Then it reconfigures the structure of controller such that some control performance is achieved. The proposed control structure has the advantage of disturbance rejection in the fault-free condition. Moreover it can recover some of control performances when a fault occurs. Different simulations have been carried out to show the performance and effectiveness of the proposed method.
TL;DR: Higher order sliding-mode-control laws are studied to deal with some spacecraft-attitude-tracking problems to verify and compare the practical usefulness of the various controllers.
Abstract: This paper studies higher order sliding-mode-control laws to deal with some spacecraft-attitude-tracking problems. Quasi-continuous second- and third-order sliding controllers and differentiators are applied to quaternion-based spacecraft-attitude-tracking maneuvers. A class of linear sliding manifolds is selected as a function of angular velocities and quaternion errors. The second method of Lyapunov is used to show that tracking is achieved globally. An example of multiaxial attitude-tracking maneuvers is presented, and simulation results are included to verify and compare the practical usefulness of the various controllers.
TL;DR: In this article, a new reaching law is proposed and the corresponding reachability is investigated, and the sliding mode control problem is considered for discrete-time systems, where some existing definitions on the quasi-sliding mode and reaching condition are examined.
Abstract: In this study, the sliding mode control problem is considered for discrete-time systems. Firstly, some existing definitions on the quasi-sliding mode and reaching condition are examined. A new reaching law is proposed and the corresponding reachability is investigated. Comparisons between the proposed strategies and some existing works are also made. Finally, illustrative simulation results are provided.
TL;DR: In this paper, a sliding mode control for vessel dynamic positioning is proposed. But, the performance of the controller is evaluated numerically and experimentally in order to address its effectiveness, and the results are compared with those obtained from conventional PID controller.
TL;DR: By controlling the wheel slip at the optimal value, the proposed traction control enables antiskid braking and antispin acceleration, thus improving safety in difficult weather conditions, as well as stability during high-performance driving.
Abstract: During skid braking and spin acceleration, the driving force exerted by the tires is reduced considerably, and the vehicle cannot speed up or brake as desired. It may become very difficult to control the vehicle under these conditions. To solve this problem, a second-order sliding-mode traction controller is presented in this paper. The controller design is coupled with the design of a suitable sliding-mode observer to estimate the tire-road adhesion coefficient. The traction control is achieved by maintaining the wheel slip at a desired value. In particular, by controlling the wheel slip at the optimal value, the proposed traction control enables antiskid braking and antispin acceleration, thus improving safety in difficult weather conditions, as well as stability during high-performance driving. The choice of second-order sliding-mode control methodology is motivated by its robustness feature with respect to parameter uncertainties and disturbances, which are typical of the automotive context. Moreover, the proposed second-order sliding-mode controller, in contrast to conventional sliding-mode controllers, generates continuous control actions, thus being particularly suitable for application to automotive systems.
TL;DR: It has been shown that, not only the performance of the proposed method is satisfying with an acceptable level of control signal, but also a rather simple stability analysis is performed.
Abstract: Synchronization of chaotic and uncertain Duffing-Holmes system has been done using the sliding mode control strategy. Regarding the synchronization task as a control problem, fractional order mathematics is used to express the system and sliding mode for synchronization. It has been shown that, not only the performance of the proposed method is satisfying with an acceptable level of control signal, but also a rather simple stability analysis is performed. The latter is usually a complicated task for uncertain nonlinear chaotic systems.
TL;DR: An observer-based fuzzy neural sliding mode control scheme for interconnected unknown chaotic systems is developed and can avoid the time-consuming trial-and-error tuning procedure for determining the network structure of fuzzy neural network.
TL;DR: A new position-control method is proposed that is as accurate as conventional PID control during normal operation, but is capable of slow, overdamped resuming motion without overshoots from large positional errors that result in actuator-force saturation.
Abstract: High-gain proportional-integral-derivative (PID) position control involves some risk of unsafe behaviors in cases of abnormal events, such as unexpected environment contacts and temporary power failures. This paper proposes a new position-control method that is as accurate as conventional PID control during normal operation, but is capable of slow, overdamped resuming motion without overshoots from large positional errors that result in actuator-force saturation. The proposed method, which we call proxy-based sliding mode control (PSMC), is an alternative approximation of a simplest type of sliding mode control (SMC), and also is an extension of the PID control. The validity of the proposed method is demonstrated through stability analysis and experimental results.
TL;DR: This technical note investigates the design of sliding mode control subject to packet losses, and using the stochastic Lyapunov method, the state trajectories are shown to enter into (in mean square) a neighborhood of the specified sliding surface.
Abstract: This technical note investigates the design of sliding mode control subject to packet losses. It is assumed that there exists a communication network in the feedback loop, and the dropout of data packet may occur. First, an estimation method is proposed to compensate the packet dropout. Subsequently, a discrete-time integral sliding surface involving dropout probability is introduced and a sliding mode controller is designed. By using the stochastic Lyapunov method, the state trajectories are shown to enter into (in mean square) a neighborhood of the specified sliding surface. Meanwhile, the stability of sliding mode dynamics is also ensured. Finally, numerical simulation example is provided.
TL;DR: A frequency-domain method is proposed for the determination of net hysteresis bandwidth for a given desired maximum switching frequency of the inverter, and a hierarchical switching algorithm has been suggested for the modular cells of the cascaded multilevel inverter.
Abstract: In this paper, a generalized multiband hysteresis modulation and its characterization have been proposed for the sliding-mode control of cascaded H-bridge multilevel-inverter (CHBMLI)-controlled systems A frequency-domain method is proposed for the determination of net hysteresis bandwidth for a given desired maximum switching frequency of the inverter The switching transition concept of Tsypkin's method and the describing function of nonlinear relay have been used for the derivation of results A hierarchical switching algorithm has been suggested for the modular cells of the cascaded multilevel inverter The hierarchy of each cell is swapped sequentially to provide the self-balancing capability in case the dc-link voltage is supported by the capacitors The simulation and experimental verification of the derived results are provided through a single-phase distribution static compensator (DSTATCOM) model The application in the three-phase system has been shown through simulation studies on a 33-kV distribution-system compensation using DSTATCOM Verification on both single- and three-phase systems is obtained using a five-level cascaded-multilevel-inverter topology
TL;DR: This work describes the development of a dynamic positioning system for remotely operated underwater vehicles that is primarily based on the sliding mode control strategy and enhanced by an adaptive fuzzy algorithm for uncertainty/disturbance compensation.
TL;DR: In this article, a semi-active control algorithm for a MR suspension system from a variety of semiactive control algorithms for use with MR dampers is presented. And the results show that the performance of MR suspension systems is highly dependent on the choice of algorithm employed, and the sliding mode control strategy exhibits an excellent integrated performance.
Abstract: This paper presents the comparison results of a study to identify an appropriate semi-active control algorithm for a MR suspension system from a variety of semi-active control algorithms for use with MR dampers. Five representative control algorithms are considered including the skyhook controller, the hybrid controller, the LQG controller, the sliding mode controller and the fuzzy logic controller. To compare the control performances of the five control algorithms, a quarter car model with a MR damper is adopted as the baseline model for our analysis. After deriving the governing motion equations of the proposed dynamic model, five controllers are developed. Then each control policy is applied to the baseline model equipped with a MR damper. The performances of each control algorithm under various road conditions are compared along with the equivalent passive model in both time and frequency domains through the numerical simulation. Subsequently, a road test is performed to validate the actual control performance. The results show that the performance of a MR suspension system is highly dependent on the choice of algorithm employed, and the sliding mode control strategy exhibits an excellent integrated performance.