Sliding modes in power electronics and motion control systems

An induction generator (IG) speed drive with the application of a sliding mode controller and a proposed fuzzy neural network (FNN) controller is introduced in this paper. Grid connected wind energy conversion system (WECS) present interesting control demands, due to the intrinsic nonlinear characteristic of wind mills and electric generators. The FNN torque compensation is feedforward to increase the robustness of the wind driven induction generator system. A multivariable controller is designed to drive the turbine speed to extract maximum power from the wind and adjust to the power regulation. Moreover, a sliding mode speed controller is designed based on an integral-proportional (IP) sliding surface. When sliding mode occurs on the sliding surface, the control system acts as a robust state feedback system.

Sliding mode control based dynamic voltage restorer for voltage sag compensation

Sliding mode control is known for its robustness against plant uncertainties and disturbance rejection. An extension of this technique is the addition of super twisting algorithm that suppresses the chattering effect commonly observed with sliding mode control application. This paper elaborates on the design and analysis of the super twisting algorithm with focus on optimizing the gain parameters. Two main components of the sliding mode super twisting controller were designed and validated; that is, the switching function and the control laws. The traditional sliding surface was used as the switching function while control laws with continuous control action were applied. Two gain parameters of the control laws were designed and analyzed in terms of tracking error reduction and chattering effect. A Kalman-Bucy continuous filter was applied for velocity signal estimation. Fast Fourier Transform was applied on the control inputs to investigate the chattering amplitude and root mean square of the tracking error was used as performance indicator for tracking error reduction. Analyses were performed on the effect of gains variation to control performance. Experimental results showed that gain L was sensitive to chattering amplitude while gain W provided wider range of tuning. The control performance was compared to the traditional pseudo-sliding mode controller in terms of tracking error reduction and chattering effect. Results showed that the super twisting algorithm produced superior results in tracking error reduction and was effective in suppressing chattering effect compared to the pseudo-sliding mode controller.

In this paper a sliding mode control (SMC) of DC machine is presented. The main arguments in favor of sliding mode control are order reduction, decoupling design procedure, fast response, disturbances rejection, and insensitivity to parameter variations. In SMC with unmodelled dynamics chattering phenomenon is eliminated by constructing the sliding manifold based on reduced order model of the system with observer state. In case of high order models of electric machines, non-linear ties in motion equations; uncertainties in model parameters and disturbances are the main obstacles for development and rigorous mathematical analysis of such systems. The simulation result depicts that the integral square error (ISE) performance index for reduced order model of the system with observer state is better than reduced order with measured state.

Electrical machine control is the essential technology in motion control field. Electrical machine is adding the network communication module in their traditional control unit, while motion control is stretching its way toward remote motion control domain. The Web-based network motion control is really a way to develop remote motion control in an open area; it gives more chances to operate and update the motion control equipments far from the workshop. The author aims at applying an extending network communication module to the traditional electrical machine control unit and some special problems aroused from making use of J2EE Platform technology in electrical machine control, such as the interface between software and control unit of electrical machine control, and the server of the remote electrical machine control. In this paper a subminiature permanent DC motor is connected to the server via RS232 serial port and is also used as an object for remote control, the author present the difficulties in building the B/S (Browser/Server) structure which can operate the electric machine through the Internet far from our lab, and gives some possible ways and some novel ideal to solve the problem

The chattering and offset phenomena, which may lead to acceleration disturbances and deteriorate control performance, are the main deficiencies caused by switching signal and mismatched uncertainties when the sliding mode control method is used for motion control systems with friction. The need is highlighted for simultaneous chattering suppression and mismatched uncertainties attenuation of sliding mode control. In this article, a switched sliding mode control method is proposed which uses three sliding surfaces to divide the error state space into three subspaces. Using different sliding mode controllers when error system state is located in different subspaces, the asymptotically stable of motion control system is guaranteed under friction and uncertainties (including matched and mismatched). In addition, through designing proper switching gain for each sliding mode controller, the control law of switched sliding mode control can be continuous. This means that the chattering phenomenon caused by switching gain will be suppressed effectively. For improving the tracking performance, a switched sliding mode control–based composite controller incorporating a LuGre model–based adaptive approximator is further presented. The predicted friction of LuGre model is used for friction compensation based on switched sliding mode control. Experimental results based on three different controllers verify the effectiveness of the proposed method on a test-bed.

A position tracking control method of permanent magnet synchronous motor (PMSM) is presented based on sliding mode control (SMC) and adaptive backstepping method. The adaptive backstepping controller is proposed for PMSM position loop and speed loop control. A adaptive backstepping observer is adopted to estimate the load torque. Regarding the current control of PMSM, the sliding mode controller with a novel sliding-mode exponential reaching law is presented. Finally, the stability of the entire system is verified by Lyapunov theory. The results of the experiment demonstrate that the proposed control algorithm achieves desirable position tracking property as well as good load disturbance attenuation.

This paper presents the application of Ontpnt Subspace’ !&abilization and Linear Adaptive Control Methdology to controlling tailess aircmft. The absence of a vertical stabilator and of a rudder reqnires combining the operation of several control surfaces to control each channel conversely each actuator contriie to the controlling of several control channels. As a result, the control problem is a Multiple InpntMultiple Ontpnt control problem, with very significant couplings between pit& roll and yaw channels. Application of Linear Adaptive Control Methodollogy’” circumvents the use of complicated nonlinear control techniques, and the attendsnt analysis uncertainties. The use of real-time dkhnbanceobserver~‘~ allows treating the entire response of the sy9teq with the exceptiou of the control term as a disturbance, and’to use the estimauon of the disturbance to “cancel-out” this ~esponse~~ and thereby effectively de-coupling the control channels while avoiding to have to model inter-chatmels coupling terms. Subspace st&ilizatiod” control allow to using the effects of one or of several actuators to steer the system error-state to a certain s&qace S (hyperplane) Which represents the prescribed ideal tracking error behavior, while suitably bounding the !abequent motion on the s&space S. Simulation results for a worked example demonstrate that the pre controller tracks prescribed trajectories accurately. 1. Introdnction Flying wings and tailess aimaft are design attempts to enhance combat ai.rm& operational performances, by the removing of vertical stabilators and the blending of the wing and fuselage. The downside of such design is the considerable redaction ofahcra8transversalliflslopeanddutchrolldamping New aim& aw beiug equipped with multiple redundmt control su&ceq that properly deflected can produc& requimi pitch, roll, and yaw moments. This 1Copyright01999bytheAmericanInstituteof Aeronautics and Astronautics, Inc. All rights reserved C. D. Johnson” The University of Alabama in Huntsville, Huntsville, AL 35899 cmflguration exhibits a considerable coupling of the control channels. Any pitch, roll, and yaw maneuver requires deflecting multiple aerodynamic ontrols such as elevons, pitch flaps, all moving tips, and eventual thmt vectoring. Conversely the deflection of any control actuator, afhxts multiple control channels. A solution to this problem” was presentedbased in H, and ~synthesis, which is the application of References12‘14 to the case of tailess aircmfl. Bufi@ton’5 has studied the opt&z&ion of the utilization of multiple rcxlmbt control smfaces. Several researcherPg have investigated the application of Sliding Mode Control as a means to achieve the desired robustness. Reference’g investigated thedesignofatailessaircraftcontroldesignbasedon sliding mode control. It does not require a detailed knowledge of the plant, which makes this technique robust. It is based on the property that daring high &eqnency switching (chattering) of the control, motion of the system state in the sliding surface remains insensitive to certain parameter TGW.illtiq nonlinearities and dktmbances. Discontimtous, bangbang control is used to move the system to the switching surface, and high-freqnency bang-bang control is used to keep it an-the sliding.su&ice thereafter. The ideal high-tkquency control is supposed filtered b the low-pass actuators, i.e. hydraulic jacks. The imperfect filtering of the high tiqnncy switching may excite vehicle structural modes, which is serious enough to prechtde the use of disconthmous relay controllers. The so-called smoothing sliding mode controls approach used in RefercncePg consists in substituting the relay discontinuous control by a satmation discontimmus control law. The linear porti0r.k of the control law corresponds to the opxation of the system in the close boundary layer of the surface. i Senior Scientist, Senior Member, AIAA ii Professor, Department of Electrical and Computer Engineering

In this paper, the principle and characteristics of friction drive is analyzed. The mathematical model of the LAMOST telescope mount drive control system is established and the fuzzy sliding mode control theory is put forward to contrast with traditional PID control and ordinary sliding mode control, which is realized by Matlab/simulink simulation. The simulation results show that the fuzzy sliding mode control has good performance of speed tracking.Keywordsservo systemsliding modefuzzy sliding mode

A number of papers have been written exploring the application of Sliding Mode Control to spacecraft positional and attitude control using thrusters. However, these papers usually consider only the control aspect of the problem. In that respect, Sliding Mode Control yields excellent performance. However, an oft neglected factor in this analysis is fuel consumption. Particularly in space, fuel is a precious commodity that is like a lifeline for a spacecraft. In this paper we consider the fuel usage for sliding mode control used to achieve orbital rendezvous. It is found that the exceptional performance of the sliding mode controller comes at a cost of significant fuel usage. In its stead, we propose a more fuel efficient controller, that takes longer to achieve rendezvous, but minimizes the fuel used to do so. Nomenclature k0 Altitude of target orbit r Relative position of chase vehicle in R direction c Relative position of chase vehicle in C direction o Relative position of chase vehicle in O direction s Sliding variable ui Acceleration in direction i m(t) Mass at time t Ti Thrust in direction i vrel Relative velocity of the exhaust gases from the thruster di Disturbance (perturbation) in direction i H Hamiltonian of the system x State variables p Co-state variables

Purpose The paper presents the results of work on control systems of bearingless electric motors. Authors proposed the applications of bearingless electric machines for aircraft actuation system. Suggested solution characterizes novel concept of on-board equipment design such as More Electric Aircraft. Magnetic suspension technology allows elimination of friction force and the negative performance features of classic bearing system. However, to achieve all these purposes appropriately, dedicated control system must be also applied. Design/methodology/approach The development of a control system of bearingless electric machine is presented in detail. Mathematical model and construction of induction bearingless motor are widely discussed. Then, proportional–integral-derivative controller algorithm designing for BEM control system was presented using the well pole placement method. Simulation model of BEM control system with use of Matlab-Simulink software was shown. Finally, experimental studies on laboratory stand were introduced. The paper presents design methodology of conventional and advanced control system of bearingless motor. Findings The presented concept of the bearingless electric machines could be applied in the on-board actuation system. During research, full control system of bearingless electric motor was designed and tested. This system consisted of two subsystems. The first responded for rotary speed stabilization and second one was designed for position control of the rotor in the air gap. Practical implications The presented concept of the bearingless electric machines could be applied in the on-board actuation system. During research, full control system of bearingless electric motor was designed and tested. This system consisted of two subsystems. The first responded for rotary speed stabilization and second one was designed for position control of the rotor in the air gap. Originality/value The idea of active magnetic suspension system will be implemented for aviation on technology readiness level V. The paper presents unique laboratory stand with bearingless electric motor and experimental studies. The stable time responses of designed control system were presented and discussed. In addition, preliminary considerations of advanced control system with robust controller were introduced as well.

Sliding Mode Control is a nonlinear control methodology based on the use of a discontinuous control input which forces the controlled system to switch from one structure to another, evolving as a variable structure system. This structure variation makes the system state reach in a finite time a pre-specified subspace of the system state space where the desired dynamical properties are assigned to the controlled system. In the past years, an extensive literature has been devoted to the developments of Sliding Mode Control theory. This kind of methodology offers a number of benefits, the major of which is its robustness versus a significant class of uncertainties and disturbances during the sliding mode. Yet, it presents a crucial drawback, the so-called chattering, which may disrupt or damage the actuators and induce unacceptable vibrations throughout the controlled system. This limits the practical applicability of the methodology, especially in case of mechanical or electromechanical plants. This drawback has been faced by recent theoretical developments, oriented to increase the order of the sliding mode, thus producing efficient Second Order and Higher Order Sliding Mode Control algorithms. Robustness of the controlled system, in addition, has been extended to hold since the initial time instant of the control horizon, via the so-called Integral Sliding Mode Control approach. These “modern” results can be profitably used to efficiently solve automotive control problems, as testified by several recent publications and research projects. The aim of this lecture is to provide an outline of the mentioned theoretical advancements, and an overview of available examples of application of sliding mode control to the automotive field, focusing on recent activities developed by the research group chaired by Prof. Ferrara at the University of Pavia.

A practical design sliding mode controller for DC–DC converter based on control parameters optimization using assigned poles associate to genetic algorithm

This study presents an output feedback‐based sliding mode control approach for motion control systems with mismatched/matched disturbances. The key idea of this study is to reconstruct the unmeasured auxiliary states and disturbances synchronously online by constructing a higher‐order extended state observer (HOESO). It is shown that the resulting sliding mode controller based on HOESO can drive the system output to an ultimately bounded region, which can be regulated arbitrarily small by assigning a sufficiently large scaling gain. Different from the existing extended state observer methods, the newly proposed HOESO treats the known dynamics satisfying the Lipschitz condition and the unknown higher‐order disturbances separately. As such, it provides a feasible way for higher‐precision states/disturbance estimation. Thanks to the utilisation of HOESO, the upper bound of disturbances is not necessarily required as a priori and the switching gain is adaptively chosen based on the estimation error such that the chattering effects can be significantly reduced. Experiments for speed regulation of a brushless DC motor are conducted to verify the effectiveness of the proposed method.

The main objective of this paper is to control the speed of separately excited DC Motor using a Sliding mode controller based on VSS approach. This controller is based on variable structure systems which aim at reducing the peak overshoot, steady state error and settling time of a DC Motor. In the first stage, PI controller is used to control the speed of DC Motor. A model is developed and simulated using MATLAB/SIMULINK. Later on the same is done with sliding mode controller. The speed control of DC Motor using both PI and Sliding mode controllers is studied and the results are compared. The simulation results show that Sliding mode controller is superior than PI for speed control of DC motor. Since the SMC is robust in presence of disturbances, the desired speed is perfectly tracked.