Showing papers on "Sliding mode control published in 2008"
TL;DR: A simple classification of the most important types of predictive control is introduced, and each one of them is explained including some application examples.
Abstract: Predictive control is a very wide class of controllers that have found rather recent application in the control of power converters. Research on this topic has been increased in the last years due to the possibilities of today's microprocessors used for the control. This paper presents the application of different predictive control methods to power electronics and drives. A simple classification of the most important types of predictive control is introduced, and each one of them is explained including some application examples. Predictive control presents several advantages that make it suitable for the control of power converters and drives. The different control schemes and applications presented in this paper illustrate the effectiveness and flexibility of predictive control.
1,389 citations
18 Nov 2008
TL;DR: In this article, a Powerpoint presentation on predictive control in power electronics and drives is presented, where the areas discussed include predictive control, power electronics, power drive, cascaded control structure, nonlinear control system, switching system, etc.
Abstract: The article consists of a Powerpoint presentation on predictive control in power electronics and drives. The areas discussed include: predictive control; power electronics; power drive; cascaded control structure; nonlinear control system; switching system; etc. etc.
1,073 citations
TL;DR: It has been shown that the use of SM control can lead to an improved robustness in providing consistent transient responses over a wide range of operating conditions and is compared with that of conventional linear control in terms of transient characteristics.
Abstract: This paper examines the practical design issues of sliding-mode (SM) controllers as applied to the control of dc-dc converters. A comprehensive review of the relevant literature is first provided. Major problems that prevent the use of SM control in dc-dc converters for industrial and commercial applications are investigated. Possible solutions are derived, and practical design procedures are outlined. The performance of SM control is compared with that of conventional linear control in terms of transient characteristics. It has been shown that the use of SM control can lead to an improved robustness in providing consistent transient responses over a wide range of operating conditions.
527 citations
TL;DR: The equivalent injection signal in problems relating to fault detection and condition monitoring is demonstrated and the literature in the area is presented and qualified in the context of continuing developments in the broad areas of the theory and application of sliding mode observers.
Abstract: Sliding mode observers have unique properties, in that the ability to generate a sliding motion on the error between the measured plant output and the output of the observer ensures that a sliding mode observer produces a set of state estimates that are precisely commensurate with the actual output of the plant. It is also the case that analysis of the average value of the applied observer injection signal, the so-called equivalent injection signal, contains useful information about the mismatch between the model used to define the observer and the actual plant. These unique properties, coupled with the fact that the discontinuous injection signals which were perceived as problematic for many control applications have no disadvantages for software-based observer frameworks, have generated a ground swell of interest in sliding mode observer methods in recent years. This article presents an overview of both linear and non-linear sliding mode observer paradigms. The use of the equivalent injection signal in problems relating to fault detection and condition monitoring is demonstrated. A number of application specific results are also described. The literature in the area is presented and qualified in the context of continuing developments in the broad areas of the theory and application of sliding mode observers.
486 citations
TL;DR: A sliding mode control approach to stabilize a class of underactuated systems which are in cascaded form and its insensitivity to the model errors, parametric uncertainties and other disturbances and its ability to globally stabilize the system are two advantages of the sliding mode controller.
461 citations
TL;DR: In this paper, an on-line sliding mode control allocation scheme for fault tolerant control is proposed, where the effectiveness level of the actuators is used to redistribute the control signals to the remaining actuators when a fault or failure occurs.
434 citations
01 Apr 2008
TL;DR: This correspondence proposes a systematic adaptive sliding- mode controller design for the robust control of nonlinear systems with uncertain parameters and proves system robustness, as well as stability, is proven by using the Lyapunov theory.
Abstract: This correspondence proposes a systematic adaptive sliding- mode controller design for the robust control of nonlinear systems with uncertain parameters. An adaptation tuning approach without high- frequency switching is developed to deal with unknown but bounded system uncertainties. Tracking performance is guaranteed. System robustness, as well as stability, is proven by using the Lyapunov theory. The upper bounds of uncertainties are not required to be known in advance. Therefore, the proposed method can be effectively implemented. Experimental results demonstrate the effectiveness of the proposed control method.
399 citations
TL;DR: In this paper, a sliding mode control strategy is proposed to ensure stability in both operation regions and to impose the ideal feedback control solution despite model uncertainties in variable-speed wind energy conversion systems (VS-WECS).
Abstract: This paper addresses the problem of controlling power generation in variable-speed wind energy conversion systems (VS-WECS). These systems have two operation regions depending on the wind turbine tip-speed ratio. They are distinguished by minimum phase behavior in one of these regions and a nonminimum phase in the other one. A sliding mode control strategy is then proposed to ensure stability in both operation regions and to impose the ideal feedback control solution despite model uncertainties. The proposed sliding mode control strategy presents attractive features such as robustness to parametric uncertainties of the turbine and the generator as well as to electric grid disturbances. The proposed sliding mode control approach has been simulated on a 1.5-MW three-blade wind turbine to evaluate its consistency and performance. The next step was the validation using the National Renewable Energy Laboratory (NREL) wind turbine simulator called the fatigue, aerodynamics, structures, and turbulence code (FAST). Both simulation and validation results show that the proposed control strategy is effective in terms of power regulation. Moreover, the sliding mode approach is arranged so as to produce no chattering in the generated torque that could lead to increased mechanical stress because of strong torque variations.
390 citations
TL;DR: A sliding mode control law is presented and experimentally implemented for trajectory tracking of underactuated autonomous surface vessels and guarantees position tracking while the rotational motion remains bounded.
Abstract: A sliding-mode control law is presented and experimentally implemented for trajectory tracking of underactuated autonomous surface vessels. The control law is developed by introducing a first-order sliding surface in terms of surge tracking errors and a second-order surface in terms of lateral motion tracking errors. The resulting sliding-mode control law guarantees position tracking while the rotational motion remains bounded. The experimental vessel is a small boat with two propellers in an indoor pool. The position and orientation of the boat are measured using a camera that detects two infrared diodes attached near the front and back ends of the boat. A computer with a capture card processes the camera image to determine the position, calculates the control forces and their corresponding input voltages, and sends the control signals to wireless receivers on the vessel using a wireless transmitter. Several experiments are performed where the vessel accurately follows straight-line and circular trajectories.
359 citations
TL;DR: In this article, an adaptive sliding control method is presented for an electro-hydraulic system with nonlinear unknown parameters, which enter the system equations in a nonlinear way. But in practical hydraulic systems, the original control volumes are unknown or change; as a result some unknown parameters appear nonlinearly.
334 citations
TL;DR: In this article, a higher-order sliding-mode observer is proposed to estimate exactly the observable states and asymptotically the unobservable ones in multi-input-multi-output nonlinear systems with unknown inputs and stable internal dynamics.
Abstract: In this paper, a higher-order sliding-mode observer is proposed to estimate exactly the observable states and asymptotically the unobservable ones in multi-input–multi-output nonlinear systems with unknown inputs and stable internal dynamics. In addition the unknown inputs can be identified asymptotically. Numerical examples illustrate the efficacy of the proposed observer. Copyright © 2007 John Wiley & Sons, Ltd.
TL;DR: A coordinated control scheme based on a leader-follower approach is developed to achieve formation maneuvers and first and second order sliding-mode controllers are proposed for asymptotically stabilizing the vehicles to a time-varying desired formation.
Abstract: This paper considers the control of a group of autonomous mobile robots. A coordinated control scheme based on a leader-follower approach is developed to achieve formation maneuvers. First and second order sliding-mode controllers are proposed for asymptotically stabilizing the vehicles to a time-varying desired formation. The latter controller, based on the relative motion states, eliminates the need for measurement or estimation of the leader velocity. It enables formation stabilization using a vision system carried by the followers and ensures the collision avoidance from the initial time instance. Experimental investigation has been conducted using a test bench made of three nonholonomic mobile robots in order to demonstrate the effectiveness of the proposed strategy.
TL;DR: In this article, a feedback linearization-based controller with a high-order sliding mode observer running parallel is applied to a quadrotor unmanned aerial vehicle, where the observer works as an observer and estimator of the effect of the external disturbances such as wind and noise.
Abstract: In this paper, a feedback linearization-based controller with a high-order sliding mode observer running parallel is applied to a quadrotor unmanned aerial vehicle. The high-order sliding mode observer works as an observer and estimator of the effect of the external disturbances such as wind and noise. The whole observer–estimator–control law constitutes an original approach to the vehicle regulation with minimal number of sensors. Performance issues of the controller–observer are illustrated in a simulation study that takes into account parameter uncertainties and external disturbances. Copyright © 2007 John Wiley & Sons, Ltd.
TL;DR: The on-line sliding mode control allocation scheme shows that faults and even certain total actuator failures can be handled directly without reconfiguring the controller.
TL;DR: In this article, a method of smooth sliding mode control design is presented to provide for an asymptotic second-order sliding mode on the selected sliding surface in the presence of unknown disturbances and discrete-time control update.
Abstract: Presented is a method of smooth sliding mode control design to provide for an asymptotic second-order sliding mode on the selected sliding surface. The control law is a nonlinear dynamic feedback that in absence of unknown disturbances provides for an asymptotic second-order sliding mode. Application of the second-order disturbance observer in a combination with the proposed continuous control law practically gives the second-order sliding accuracy in presence of unknown disturbances and discrete-time control update. The piecewise constant control feedback is “smooth” in the sense that its derivative numerically taken at sampling rate does not contain high frequency components. A numerical example is presented.
TL;DR: In this article, a nonlinear battery dynamic modeling technique is established and design methodology with the sliding mode observer is presented, and the performance of the system has been verified by the sequence of urban dynamometer driving schedule test.
Abstract: A new method for battery state of charge estimation using a sliding mode observer has been developed. A nonlinear battery dynamic modeling technique is established and design methodology with the sliding mode observer is presented. Contrary to the conventional methods using complicated battery modeling, a simple resistor-capacitor battery model was used in this work. The modeling errors caused by the simple model are compensated by the sliding mode observer. The structure of the sliding mode observer is simple, but it shows robust control property against modeling errors and uncertainties. The convergence of the proposed observer has been proved by the equivalent control method. The performance of the system has been verified by the sequence of urban dynamometer driving schedule test. The test results of the proposed observer system shows robust tracking performance under real driving environments.
TL;DR: In this paper, the same approach of integral sliding mode control is ineffective in alleviating the converter's steady-state regulation error and the error increases as the converter switching frequency decreases, and an additional double-integral term of the controlled variables is proposed for constructing the sliding surface of indirect sliding mode controllers.
Abstract: The steady-state regulation error in power converters that use the conventional hysteresis-modulation-based sliding mode controller can be suppressed through the incorporation of an additional integral term of the state variables into the controller. However, it is found that with the indirect type of sliding mode controller (derived based on the equivalent control approach), the same approach of integral sliding mode control is ineffective in alleviating the converter's steady-state error. Moreover, the error increases as the converter's switching frequency decreases. This paper presents an in-depth study of the phenomenon and offers a solution to the problem. Specifically, it is proposed that an additional double-integral term of the controlled variables to be adopted for constructing the sliding surface of indirect sliding mode controllers. Simulation and experimental results are provided for verification.
TL;DR: A new switching control algorithm based on state trajectory approximation is proposed to regulate the output voltage of a representative second-order DC-DC converter - the boost converter to trap the system into a stable limit cycle while ensuring the required voltage regulation.
Abstract: A new switching control algorithm based on state trajectory approximation is proposed to regulate the output voltage of a representative second-order DC-DC converter - the boost converter. The essence of the proposed algorithm is to trap the system into a stable limit cycle while ensuring the required voltage regulation. Unlike some of the earlier algorithms, the concept is applicable to both continuous and discontinuous current modes of operation, making it viable over a wide operating range under various load and line disturbances. A hybrid-automaton representation of the converter is used to perform the analysis, and the control problem is simplified to a guard-selection problem. Guard conditions, governing the transition of the converter operation from one discrete state to the other in a hybrid-automaton representation, are derived. The hybrid-automaton-based control system is implemented by using the state flow chart feature of MATLAB, and extensive simulations are carried out to check the suitability of the algorithm. The hybrid control law is also validated in real time by using a laboratory prototype. The experimental and simulation results prove the effectiveness of the proposed control law under varying line and load conditions.
01 Dec 2008
TL;DR: A novel parameter adjustment scheme to improve the robustness of fuzzy sliding-mode control achieved by the use of an adaptive neuro-fuzzy inference system (ANFIS) architecture utilizes fractional-order integration in the parameter tuning stage.
Abstract: This paper presents a novel parameter adjustment scheme to improve the robustness of fuzzy sliding-mode control achieved by the use of an adaptive neuro-fuzzy inference system (ANFIS) architecture. The proposed scheme utilizes fractional-order integration in the parameter tuning stage. The controller parameters are tuned such that the system under control is driven toward the sliding regime in the traditional sense. After a comparison with the classical integer-order counterpart, it is seen that the control system with the proposed adaptation scheme displays better tracking performance, and a very high degree of robustness and insensitivity to disturbances are observed. The claims are justified through some simulations utilizing the dynamic model of a 2-DOF direct-drive robot arm. Overall, the contribution of this paper is to demonstrate that the response of the system under control is significantly better for the fractional-order integration exploited in the parameter adaptation stage than that for the classical integer-order integration.
TL;DR: In this paper, a feedback linearization theory is applied to a single-phase shunt active power filter, and a sliding mode controller is proposed to impose a desired dynamic behavior on the system.
Abstract: The aim of this work is the application of the feedback linearization theory to a single-phase shunt active power filter, since this technique has been successfully applied to other areas of power electronic. The active filter is linearized by means of a nonlinear transformation of the system model, deduced from the application of Tellegen's theorem to the system. After that, a sliding mode controller is proposed to impose a desired dynamic behavior on the system, giving robustness and insensitivity to parameter variations. Moreover, the proposed controller ensures proper tracking of the reference signals and simplifies the overall control design. The controller was implemented into a low cost DSP. Experimental and simulation results are provided.
01 Jan 2008
TL;DR: In this paper, a comprehensive analysis of chattering in Second Order Sliding Mode Control Systems is presented, along with closed-loop performance and frequency-domain design of compensating filters for sliding mode control systems.
Abstract: Part I Basic Theory.- Regularization of Second Order Sliding Mode Control Systems.- A comprehensive Analysis of Chattering in Second Order Sliding Mode Control Systems.- Analysis of Closed-Loop Performance and Frequency-Domain Design of Compensating Filters for Sliding Mode Control Systems.- Discontinuous Homogeneous Control.- Second-order Sliding Sector for Variable Structure Control.- On Euler's Discretization of Sliding Mode Control Systems with Relative Degree Restriction.- Part II Design Methods.- Circumventing the relative degree condition in sliding mode design.- HOSM driven output tracking in the nonminimum-phase causal nonlinear systems.- High Order Sliding Mode Neurocontrol for Uncertain Nonlinear SISO Systems: Theory and Applications.- A Generalized PI Sliding Mode and PWM Control of Switched Fractional Systems.- Stabilization of nonholonomic uncertain systems via adaptive second order sliding mode control.- Output Tracking with Discrete-Time Integral Sliding Mode Control.- Flatness, Backstepping and Sliding Mode Controllers for Nonlinear Systems.- Part III Observers and Fault Detection.- Observation and identification via high-order sliding modes.- High Order Sliding Mode Observers and Differentiators-Application to Fault Diagnosis Problem.- Vehicle Parameter and States Estimation via Sliding Mode Observers.- An alternative to the measurement of five-links biped robot absolute orientation: estimation based on high order sliding mode.- Part IV Applications.- Robust Orbital Stabilization of Pendubot: Algorithm Synthesis, Experimental Verification, and Application to Swing up and Balancing Control.- Higher Order SM Block-Control of Nonlinear Systems with Unmodeled Actuators. Application to electric power systems and electrohydraulic servo-drives.- Blood Glucose Regulation Via Double Loop Higher Order Sliding Mode Control and Multiple Sampling Rate.- Contact force regulation in wire-actuated pantographs.
TL;DR: A sliding-mode approach for fault-tolerant control of a civil aircraft, where both actuator and sensor faults are considered, and the novelty lies in the application of the sensor fault reconstruction scheme to correct the corrupted measured signals before they are used by the controller.
Abstract: This paper presents a sliding-mode approach for fault-tolerant control of a civil aircraft, where both actuator and sensor faults are considered. For actuator faults, a controller is designed around a state-feedback sliding-mode scheme where the gain of the nonlinear unit vector term is allowed to adaptively increase at the onset of a fault. Unexpected deviation of the switching variables from their nominal condition triggers the adaptation mechanism. The controller proposed here is relatively simple and yet is shown to work across the entire "up and away" flight envelope. For sensor faults, the application of a robust method for fault reconstruction using a sliding-mode observer is considered. The novelty lies in the application of the sensor fault reconstruction scheme to correct the corrupted measured signals before they are used by the controller, and therefore the controller does not need to be reconfigured.
TL;DR: The development of a depth control system for remotely operated underwater vehicles is described, based on the sliding mode control strategy and enhanced by an adaptive fuzzy algorithm for uncertainty/disturbance compensation and the stability and convergence properties of the closed-loop system are analytically proved.
TL;DR: A robust control algorithm for stabilization of a three-axis stabilized flexible spacecraft in the presence of parametric uncertainty, external disturbances and control input nonlinearity/dead-zone is proposed.
TL;DR: In this article, the output power control of a wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG) is presented. And the performance of the closed-loop system is assessed through representative computer simulations.
Abstract: This paper presents the output power control of a wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). It is assumed that the considered wind module integrates a stand-alone hybrid generation system, jointly with a battery bank, a variable ac load, and other generation subsystems. The operation strategy of the hybrid system determines two possible operation modes for the WECS, depending on the power requirements of the load and the wind availability. The paper deals with the design of a combined high-order sliding mode (HOSM) controller for the power control of the WECS on both operational modes. The main features of the obtained controller are its chattering-free behavior, its finite-time reaching phase, its simplicity, and its robustness with respect to external disturbances and unmodeled dynamics. The performance of the closed-loop system is assessed through representative computer simulations.
TL;DR: The proposed control law ensures the global stability of the controlled piezo-actuated stage, and the position error can be controlled to be as small as required by choosing the design parameters.
Abstract: The piezo-actuated stage is composed of a piezoelectric actuator (PEA) and a positioning mechanism (PM). Due to the existence of hysteretic nonlinearity in the PEA and the friction behavior in the PM, the accurate position control of the piezo-actuated stage is a challenging task. This paper discusses the adaptive sliding mode control for the piezo-actuated stage, where the hysteresis is described by the Prandtl-Ishlinskii model. This paper tries to fuse the hysteresis model with the adaptive control techniques, where the real value of the parameters of the stage need neither be identified nor be measured. The proposed control law ensures the global stability of the controlled piezo-actuated stage, and the position error can be controlled to be as small as required by choosing the design parameters. Experimental results show the effectiveness of the proposed method.
TL;DR: A robust fuzzy sliding-mode controller for active suspensions of a nonlinear half-car model and it has been shown that the designed controller does not cause any problem in suspension working limits.
Abstract: In this paper, a robust fuzzy sliding-mode controller for active suspensions of a nonlinear half-car model is introduced. First, a nonchattering sliding-mode control is presented. Then, this control method is combined with a single-input-single-output fuzzy logic controller to improve its performance. The negative value of the ratio between the derivative of error and error is the input and the slope constant of the sliding surface of the nonchattering sliding-mode controller is the output of the fuzzy logic controller. Afterwards, a four-degree-of-freedom nonlinear half-car model, which allows wheel hops and includes a suspension system with nonlinear spring and piecewise linear damper with dry friction, is presented. The designed controllers are applied to this model in order to evaluate their performances. It has been shown that the designed controller does not cause any problem in suspension working limits. The robustness of the proposed controller is also investigated for different vehicle parameters. The results indicate the success of the proposed fuzzy sliding-mode controller.
TL;DR: In this article, a sliding mode control of a continuous-time switched system with time-varying delay in its state is considered, and a sufficient condition of the existence of a reduced-order sliding mode dynamics is derived, and an explicit parametrization of the desired sliding surface is also given.
Abstract: This paper is concerned with the sliding mode control of a continuous-time switched system with time-varying delay in its state. By using the average dwell time approach and the piecewise Lyapunov function technique, a sufficient condition is first proposed to guarantee the exponential stability of the unforced system with the decay estimate explicitly given. A sufficient condition of the existence of a reduced-order sliding mode dynamics is derived, and an explicit parametrization of the desired sliding surface is also given. The obtained conditions will be solved using the cone complementary linearization (CCL) method. An adaptive sliding mode controller for the reaching motion is then designed such that the trajectories of the resulting closed-loop system can be driven onto a prescribed sliding surface and maintained there for all subsequent times. All the conditions obtained in this paper are delay dependent. Finally, two numerical examples are given to illustrate the effectiveness of the proposed theory. Copyright © 2008 John Wiley & Sons, Ltd.
TL;DR: The problem of vehicle yaw control is addressed in this paper using an active differential and yaw rate feedback using a reference generator and second-order sliding mode methodology to guarantee robust stability in front of disturbances and model uncertainties.
Abstract: The problem of vehicle yaw control is addressed in this paper using an active differential and yaw rate feedback. A reference generator, designed to improve vehicle handling, provides the desired yaw rate value to be achieved by the closed loop controller. The latter is designed using the second-order sliding mode (SOSM) methodology to guarantee robust stability in front of disturbances and model uncertainties, which are typical of the automotive context. A feedforward control contribution is also employed to enhance the transient system response. The control derivative is constructed as a discontinuous signal, attaining an SOSM on a suitably selected sliding manifold. Thus, the actual control input results in being continuous, as it is needed in the considered context. Simulations performed using a realistic nonlinear model of the considered vehicle show the effectiveness of the proposed approach.
TL;DR: A cascaded sliding-mode (SM) control scheme for a new pneumatic linear axis which could be seen as alternative to an electric direct linear drive and shows an excellent control performance that outperforms alternative control approaches in a comparison.
Abstract: This paper presents a cascaded sliding-mode (SM) control scheme for a new pneumatic linear axis which could be seen as alternative to an electric direct linear drive. Its guided carriage is driven by a nonlinear mechanism consisting of a rocker with an antagonistic pair of pneumatic muscle actuators arranged at both sides. This innovative drive concept allows for both an increased workspace of approximately 1 m as well as higher carriage velocities of approximately 1.3 m/s as compared to a direct actuation. Modeling of the muscle-driven positioning system leads to a system of four nonlinear differential equations including polynomial approximations of the volume characteristic as well as the force characteristic of the pneumatic muscles. The differential flatness of the system is exploited in combination with SM techniques to stabilize the error dynamics in view of unmodeled dynamics. The internal pressure of each pneumatic muscle is controlled by a fast underlying control loop. Hence, the control design for the outer control loop can be simplified by considering these controlled muscle pressures as ideal control inputs. The control design of the outer control loop involves a decoupling of rocker angle as well as mean internal pressure of both pneumatic muscles as flat outputs. Additionally, model uncertainties in the equation of motion like nonlinear friction are directly counteracted by an observer-based disturbance compensation which reduces the chattering problem. Experimental results show an excellent control performance that outperforms alternative control approaches in a comparison.