Showing papers on "Sliding mode control published in 1998"
Book•
27 Aug 1998
TL;DR: This text provides the reader with a grounding in sliding mode control and is appropriate for the graduate with a basic knowledge of classical control theory and some knowledge of state-space methods.
Abstract: In the formation of any control problem there will be discrepancies between the actual plant and the mathematical model for controller design. Sliding mode control theory seeks to produce controllers to over some such mismatches. This text provides the reader with a grounding in sliding mode control and is appropriate for the graduate with a basic knowledge of classical control theory and some knowledge of state-space methods. From this basis, more advanced theoretical results are developed. Two industrial case studies, which present the results of sliding mode controller implementations, are used to illustrate the successful practical application theory.
3,355 citations
TL;DR: A new solution to the problem of chattering elimination in variable structure control (VSC) is presented, inspired by the classical bang-bang optimal control strategy, and extended to the case of nonlinear systems with uncertainties of more general types.
Abstract: Relying on the possibility of generating a second-order sliding motion by using, as control, the first derivative of the control signal instead of the actual control, a new solution to the problem of chattering elimination in variable structure control (VSC) is presented. Such a solution, inspired by the classical bang-bang optimal control strategy, is first depicted and expressed in terms of a control algorithm by introducing a suitable auxiliary problem involving a second-order uncertain system with unavailable velocity. Then, the applicability of the algorithm is extended, via suitable modifications, to the case of nonlinear systems with uncertainties of more general types. The proposed algorithm does not require the use of observers and differential inequalities and can be applied in practice by exploiting such commercial components as peak detectors or other approximated methods to evaluate the change of the sign of the derivative of the quantity accounting for the distance to the sliding manifold.
992 citations
TL;DR: A new definition describing the quasi-sliding mode as a motion of the system, such that its state always remains in a certain band around the sliding hyperplane, is introduced and two novel reaching laws satisfying conditions of the definition are proposed and applied to the design of appropriate linear control strategies.
Abstract: In this paper, discrete-time quasi-sliding-mode control systems are considered. A new definition describing the quasi-sliding mode as a motion of the system, such that its state always remains in a certain band around the sliding hyperplane, is introduced. Then, two novel reaching laws satisfying conditions of the definition are proposed and applied to the design of appropriate linear control strategies which drive the state of the controlled system to a band around the sliding hyperplane. Consequently, the undesirable chattering and high-frequency switching between different values of the control signal are avoided. The strategies, when compared with previously published results, guarantee better robustness, faster error convergence, and improved steady-state accuracy of the system. Furthermore, better performance of the system is achieved using essentially reduced control effort.
560 citations
TL;DR: In this article, a terminal sliding mode control design scheme for uncertain dynamic systems in the pure-feedback form is presented, which employs a recursive procedure which utilizes a set of switching manifolds to realize finite time convergence.
487 citations
TL;DR: The proposed scheme simplifies significantly the controller designs given in Venkataraman and Gulati (1989) and Man et al. (1994) by reducing tracking error in the steady state and reduced control efforts in the transient state.
467 citations
TL;DR: Two methods of adaptive SMC schemes that the fuzzy logic systems (approximators) are used to approximate the unknown system functions in designing the SMC of nonlinear system are proposed.
Abstract: In this paper, the fuzzy approximator and sliding mode control (SMC) scheme are considered. We propose two methods of adaptive SMC schemes that the fuzzy logic systems (approximators) are used to approximate the unknown system functions in designing the SMC of nonlinear system. In the first method, a fuzzy logic system is utilized to approximate the unknown function f of the nonlinear system x/sup n=/f(x, t)+b(x, t)u and the robust adaptive law is proposed to reduce the approximation errors between the true nonlinear functions and fuzzy approximators. In the second method, two fuzzy logic systems are utilized to approximate the f and b, respectively, and the control law, which is robust to approximation error is also designed. The stabilities of proposed control schemes are proved and these schemes are applied to an inverted pendulum system. The comparisons between the proposed control schemes are shown in simulations.
317 citations
TL;DR: The decoupled sliding-mode control (SMC) is used to control three highly nonlinear systems and confirms the validity of the proposed approach.
Abstract: A decoupled fuzzy sliding-mode controller design is proposed. The decoupled method provides a simple way to achieve asymptotic stability for a class of fourth-order nonlinear systems with only five fuzzy control rules. The ideas behind the controller are as follows. First, decouple the whole system into two second-order systems such that each subsystem has a separate control target expressed in terms of a sliding surface. Then, information from the secondary target conditions the main target, which, in turn, generates a control action to make both subsystems move toward their sliding surface, respectively. A closely related fuzzy controller to the sliding-mode controller is also presented to show the theoretical aspect of the fuzzy approach in which the characteristics of fuzzy sets are determined analytically to ensure the stability and robustness of the fuzzy controller. Finally, the decoupled sliding-mode control (SMC) is used to control three highly nonlinear systems and confirms the validity of the proposed approach.
264 citations
TL;DR: It is shown that the discontinuity plane for sliding mode control may be found in an explicit form using Ackermann's formula.
Abstract: The sliding mode control methods are developed to design systems which have the desired dynamic behavior and are robust with respect to perturbations. It is shown that the discontinuity plane for sliding mode control may be found in an explicit form using Ackermann's formula. Two design procedures are derived. First, static controllers are designed to enforce sliding modes with the desired dynamic properties after a finite-time interval. Then, dynamic controllers are designed that exhibit the desired dynamic properties during the entire control process.
257 citations
TL;DR: In this paper, a sliding mode observer design based on the equivalent control approach is discussed for a linear time invariant system both in continuous and discrete time, where the observer is eventually expressed as a replica of the original system with an auxiliary input with a certain nested structure.
Abstract: In this paper, sliding mode observer design principles based on the equivalent control approach are discussed for a linear time invariant system both in continuous and discrete time. For the continuous case, the observer is designed using a recursive procedure; however, the observer is eventually expressed as a replica of the original system with an additional auxiliary input with a certain nested structure. A direct discrete time counterpart of the sliding mode realization of a reduced order asymptotic observer using the discrete time equivalent control is also developed. Simulation of a linearized truck-trailer during a manoeuvre illustrates the approach. Results show the effectiveness and the finite time convergence characteristics of the proposed discrete and continuous time sliding mode observers.
TL;DR: An improved adaptation law on the upper bound of uncertainties is proposed to guarantee the boundednenss of both states of the plant and the estimated control gains when the boundary layer technique is employed.
TL;DR: Using this scheme, not only strong robustness with respect to uncertain dynamics and nonlinearities can be obtained, but also the output tracking error between the plant output and the desired reference output can asymptotically converge to zero.
Abstract: A neural-network-based adaptive tracking control scheme is proposed for a class of nonlinear systems in this paper. It is shown that RBF neural networks are used to adaptively learn system uncertainty bounds in the Lyapunov sense, and the outputs of the neural networks are then used as the parameters of the controller to compensate for the effects of system uncertainties. Using this scheme, not only strong robustness with respect to uncertain dynamics and nonlinearities can be obtained, but also the output tracking error between the plant output and the desired reference output can asymptotically converge to zero. A simulation example is performed in support of the proposed neural control scheme.
01 Jan 1998
TL;DR: An adaptive fuzzy sliding-mode control system, which combines the merits of sliding- mode control, the fuzzy inference mechanism and the adaptive algorithm, is proposed and position control of a permanent magnet synchronous servo motor drive using the proposed control strategies is illustrated.
Abstract: An adaptive fuzzy sliding-mode control system, which combines the merits of sliding-mode control, the fuzzy inference mechanism and the adaptive algorithm, is proposed. First a sliding-mode controller with an integral-operation switching surface is designed. Then a fuzzy sliding-mode controller is investigated in which a simple fuzzy inference mechanism is used to estimate the upper bound of uncertainties. The fuzzy inference mechanism with centre adaptation of membership functions is investigated to estimate the optimal bound of uncertainties. Position control of a permanent magnet synchronous servo motor drive using the proposed control strategies is illustrated.
TL;DR: In this article, the authors proposed a bang-bang type sliding mode control technique to stabilize a class of chaotic systems whose nonlinearity vanishes on a sliding surface, which can be realized with practical relay devices, since it takes only two level control signals.
01 Feb 1998
TL;DR: In this paper, the control of an active suspension system using a quarter car model has been investigated due to the presence of non-linearities such as a hardening spring, a quadratic dam, and a four-cylinder engine.
Abstract: In this paper, the control of an active suspension system using a quarter car model has been investigated. Due to the presence of non-linearities such as a hardening spring, a quadratic dam...
TL;DR: A neural-network-based control design for a discrete-time nonlinear system with a multilayer perceptron of which the activation functions are of the sigmoid type symmetric to the origin and the stability of the closed-loop is guaranteed.
Abstract: We address a neural network-based control design for a discrete-time nonlinear system. Our design approach is to approximate the nonlinear system with a multilayer perceptron of which the activation functions are of the sigmoid type symmetric to the origin. A linear difference inclusion representation is then established for this class of approximating neural networks and is used to design a state feedback control law for the nonlinear system based on the certainty equivalence principle. The control design equations are shown to be a set of linear matrix inequalities where a convex optimization algorithm can be applied to determine the control signal. Further, the stability of the closed-loop is guaranteed in the sense that there exists a unique global attraction region in the neighborhood of the origin to which every trajectory of the closed-loop system converges. Finally, a simple example is presented so as to illustrate our control design procedure.
TL;DR: A new approach to the synthesis of longitudinal autopilots for missiles flying at high angle of attack regimes is presented, based on sliding mode control, and uses a combination of aerodynamic surfaces and reaction jet thrusters to achieve controllability beyond stall.
Abstract: A new approach to the synthesis of longitudinal autopilots for missiles flying at high angle of attack regimes is presented. The methodology is based on sliding mode control, and uses a combination of aerodynamic surfaces and reaction jet thrusters, to achieve controllability beyond stall. The autopilot is tested on a small section of the flight envelope consisting of a fast 180/spl deg/ heading reversal in the vertical plane, which requires robustness with respect to uncertainties in the system's dynamics induced by large variations in dynamic pressure and aerodynamic coefficients. Nonlinear simulation results show excellent performance and capabilities of the control system structure.
21 Jun 1998
TL;DR: The design of the corresponding adaptive laws based on Lyapunov analysis allow us to prove global stability of the overall scheme in the presence of multiple actuator failures.
Abstract: The paper describes the design of an automatic control reconfiguration scheme for accommodation of actuator failures in a class of plants where the number of control inputs is larger than the number of controlled outputs. One of the main features of the proposed scheme is that the control reconfiguration is achieved automatically based only on the response of the overall system. The method is developed for the case when one or more actuators freeze in a certain position and do not respond to subsequent commands. We assumed that the information about the failure is not available to the controller. To solve this problem, a control law with adjustable parameters is introduced, and, using a convenient parametrization of the overall system, the resulting error model is expressed in a somewhat modified form as compared to those arising in standard adaptive control. The design of the corresponding adaptive laws based on Lyapunov analysis allow us to prove global stability of the overall scheme in the presence of multiple actuator failures.
TL;DR: A novel nonlinear control scheme-robust iterative learning control (RILC) is developed, which provides a general framework targeting at synthesizing learning control and robust control methods with the help of Lyapunov's direct method to handle more general classes of nonlinear uncertain systems.
16 Dec 1998
TL;DR: The aim of this paper is to treat some optimal control problems for a class of hybrid systems with hybrid features and optimization problems for this class of systems.
Abstract: The aim of this paper is to treat some optimal control problems for a class of hybrid systems. We start providing a definition of hybrid system inspired by the concept introduced by Artstein (1995), who defines hybrid control in relation to stabilization problems for a classical control system. The same definition proved to be successful to tackle other stabilization problems. In this paper, we consider a class of systems with hybrid features and optimization problems for this class of systems. The word hybrid is motivated by the fact that these systems are characterized by the presence of both a continuous time evolution and a discrete time evolution. A trajectory for these systems evolves following some dynamical constraint and at some fixed or variable times (called location switching times) it jumps following the rules of a discrete time evolution. The definition of hybrid system we give is quite general and covers many interesting applications.
TL;DR: In this paper, a sliding mode controller with an integral-operation switching surface is proposed, in which a simple adaptive algorithm is utilized to estimate the bound of uncertainties. And the position control for a permanent magnet (PM) synchronous servo motor drive using the proposed control strategies is illustrated.
Abstract: A novel sliding mode controller with an integral-operation switching surface is proposed. Furthermore, an adaptive sliding mode controller is investigated, in which a simple adaptive algorithm is utilized to estimate the bound of uncertainties. The position control for a permanent magnet (PM) synchronous servo motor drive using the proposed control strategies is illustrated. The theoretical analysis and the theorems for the proposed sliding mode controllers are described in detail. Simulation and experimental results show that the proposed controllers provide high-performance dynamic characteristics and are robust with regard to plant parameter variations and external load disturbance.
TL;DR: In this article, the automatic control system (ACS) of the space nuclear reactor power system TOPAZ II that generates electricity from nuclear heat using in-core thermionic converters is considered.
Abstract: The automatic control system (ACS) of the space nuclear reactor power system TOPAZ II that generates electricity from nuclear heat using in-core thermionic converters is considered. Sliding mode control technique is applied to the reactor system controller design in order to improve robustness and accuracy of tracking of a thermal power reference profile in a start-up regime and a payload current reference profile in an operation regime. Extensive simulations of the TOPAZ II reactor system with the designed sliding mode controller showed an improvement of the reactor system performance.
TL;DR: A stable neural-network (NN)-based adaptive control approach which is an integration of an NN approach and the adaptive implementation of the variable structure control with a sector, is developed for multiinput-multioutput (MIMO) sampled-data nonlinear systems with unknown dynamic nonlinearities.
Abstract: For a class of MIMO sampled-data nonlinear systems with unknown dynamic nonlinearities, a stable neural-network (NN)-based adaptive control approach which is an integration of an NN approach and the adaptive implementation of the variable structure control with a sector, is developed. The sampled-data nonlinear system is assumed to be controllable and its state vector is available for measurement. The variable structure control with a sector serves two purposes. One is to force the system state to be within the state region in which the NN's are used when the system goes out of neural control; and the other is to provide an additional control until the system tracking error metric is controlled inside the sector within the network approximation region. The proof of a complete stability and a tracking error convergence is given and the setting of the sector and the NN parameters is discussed. It is demonstrated that the asymptotic error of the system can be made dependent only on inherent network approximation errors and the frequency range of unmodeled dynamics. Simulation studies of a two-link manipulator show the effectiveness of the proposed control approach.
TL;DR: In this paper, a comparative study of sliding-mode control and fuzzy neural network (FNN) control on the motor-toggle servomechanism is presented, where the sliding mechanism is driven by a permanent-magnet synchronous servomotor.
Abstract: A comparative study of sliding-mode control and fuzzy neural network (FNN) control on the motor-toggle servomechanism is presented. The toggle mechanism is driven by a permanent-magnet synchronous servomotor. The rod and crank of the toggle mechanism are assumed to be rigid. First, Hamilton's principle and Lagrange multiplier method are applied to formulate the equation of motion. Then, based on the principles of the sliding-mode control, a robust controller is developed to control the position of a slider of the motor-toggle servomechanism. Furthermore, an FNN controller with adaptive learning rates is implemented to control the motor-toggle servomechanism for the comparison of control characteristics. Simulation and experimental results show that both the sliding-mode and FNN controllers provide high-performance dynamic characteristics and are robust with regard to parametric variations and external disturbances. Moreover, the FNN controller can result in small control effort without chattering.
TL;DR: A new robust adaptive control architecture is proposed for operation of an inverted-pendulum mechanical system that employs a fuzzy system to adaptively compensate for the plant nonlinearities and forces the inverted pendulum to track a prescribed reference model.
Abstract: In this paper, a new robust adaptive control architecture is proposed for operation of an inverted-pendulum mechanical system. The architecture employs a fuzzy system to adaptively compensate for the plant nonlinearities and forces the inverted pendulum to track a prescribed reference model. When matching with the model occurs, the pendulum will be stabilized at an upright position and the cart should return to its zero position. The control scheme has a sliding control input to compensate for the modeling errors of the fuzzy system. The gain of the sliding input is automatically adjusted to a necessary level to ensure the stability of the overall system. Global asymptotic stability of the algorithm is established via Lyapunov's stability theorem. Experiments on an inverted-pendulum system are given to show the effectiveness of the proposed control structure.
10 Aug 1998
TL;DR: In this paper, a sliding mode controller for the X-33 vehicle in launch and re-entry mode is presented. But the authors focus on the de-coupled tracking of both the required angular velocity profiles and the desired vehicle orientation angles and take full advantage of the cascade form of the equations of motion.
Abstract: This work develops a sliding mode controller for the X-33 vehicle in launch and re-entry mode. The resulting controller utilizes two-loop sliding mode controller and provides robust, de-coupled tracking of both the required angular velocity profiles and the desired vehicle orientation angles. The motion in sliding of both the angular velocity and the orientation angles is described by linear de-coupled homogeneous vector valued differential equations with desired eigenvalues placement. An optimal control allocation algorithm is employed to allocate torque commands into end- effector deflection commands, which are executed by the actuators. Simulation of the X-33 vehicle in launch and re-entry modes demonstrated accurate, robust, de- coupled tracking performance. provides robust de-coupled multivariable tracking of the desired X-33 vehicle re-entry profiles. A sliding mode control system was designed and analyzed for the WB001 reusable launch vehicle design"*'5. This work develops a sliding mode controller (SMC) for the X-33 launch and re-entry modes. The design consists of two basic steps. First, the required angular velocity profile is determined in the outer (guidance) loop such that the given vehicle mission angle profiles are followed if the angular velocity profile is tracked. This is achieved by designing an outer-loop SMC for the kinematics equation of angular motion and taking the angular velocity as the virtual control input. Second, a suitable inner-loop SMC is designed for the dynamic equation of motion such that the required angular velocity profile is tracked. The inner-loop SMC produces control signals in terms of roll, pitch and yaw torque commands. The inner loop transient response must be much faster than the outer loop response. A control allocation algorithm is employed to allocate torque commands into end- effector deflection commands, which are executed by the actuators. The resulting two-loop SMC provides robust, de-coupled tracking of both the angular velocity profiles and the desired vehicle mission angle profiles and takes full advantage of the cascade form of the equations of motion. The motion in sliding of both the angular velocity and the mission angles is described by linear de-coupled homogeneous vector valued differential equations with desired eigenvalues placement. Simulation results demonstrating the substantive effectiveness of this controller design for the X-33 launch and re-entry modes and utilizing realistic desired angular profiles provided in table lookup format are presented.
TL;DR: A new on-line learning algorithm, based on sliding mode control (SMC), is presented and the results show that ANN inherits some of the advantages of SMC: high speed of learning and robustness.
Abstract: On-line learning algorithms for artificial neural networks (ANNs) are expected to adapt network parameters in order to face new control situations. A new on-line learning algorithm, based on sliding mode control (SMC) is presented. The results show that ANN inherits some of the advantages of SMC: high speed of learning and robustness.
TL;DR: In this paper, a time-varying hyperplane for a rotor-magnetic bearing system with a gyroscopic effect was designed, which can be considered an LPV plant due to parameter dependence on rotational speed.
Abstract: Deals with sliding mode hyperplane design for a class of linear parameter-varying (LPV) plants, the state-space matrices of which are an affine function of time varying physical parameters. The proposed hyperplane, involving a linear matrix inequality (LMI) approach, has continuous dynamics due to scheduling parameters and provides stability and robustness against parametric uncertainties. We have designed a time-varying hyperplane for a rotor-magnetic bearing system with a gyroscopic effect, which can be considered an LPV plant due to parameter dependence on rotational speed. The obtained hyperplane is continuously scheduled with respect to rotational speed. We successfully carried out experiments using a commercially available turbomolecular pump system and results were reasonable and good.
21 Jun 1998
TL;DR: Sliding mode control is applied that can handle a nonlinear system to the six degrees of freedom control for such a vehicle as the Orbital Maneuvering Vehicle or "Remover".
Abstract: Future spacecraft such as the Orbital Maneuvering Vehicle or "Remover" which tries to capture and remove large space debris objects in orbit need to be able to perform large angle and complicated position maneuvers in space. The equation of motion of a rigid body that performs attitude and translational motion (six degrees of freedom motion) is a nonlinear equation. This paper applies sliding mode control that can handle a nonlinear system to the six degrees of freedom control for such a vehicle. Its feasibility is investigated through a numerical simulation of proximity flight around a tumbling target object.