Dynamic Sliding Mode Control Research Articles

Online Hierarchical Controller for Hybrid Power System

This paper presents the basis for the development of an intelligent and autonomous energy management strategy for hybrid power system (HPS). Two hierarchical levels are proposed to control and manage the HPS. The low level is performed by a local control unit (DC-DC converters controller) of the different power sources. Dynamic equations describing the coupling of converters are derived, and a robust sliding mode dynamic controller is designed. The high level is performed by the online supervisor unit. This unit is designed by applying on-line Takagi-Sugeno fuzzy logic principles. As a result the robust control system gets rid of the limits of the HPS, which has the imprecision, uncertainty, strong coupling, and nonlinearity, to achieve its tractability, robustness, and low solution cost. Under the operation constraints related to each type of sources, the simulation results show that the optimal operation objective of HPS has been achieved.

Dynamic Sliding-Mode Control with Backstepping for Underactuated AUV in Diving Plane

A dynamic sliding-mode control (DSMC) with backstepping is proposed for diving control of autonomous underwater vehicle (AUV), where surge force and stern plane are only available for vehicle's 3DOF diving motion. First, an equivalent model of AUV is developed. Then, the DSMC with an asymptotical sliding surface is proposed for the trajectory tracking control of AUV. Moreover, the analysis of stability can be completed by Lyapunov stability theory. Finally, To demonstrate the effectiveness of the proposed method, the simulation results are illustrated in this paper. simulation results show that, the tracking precision and the robustness of the system are improved under the proposed control method.

Three-Degree-of-Freedom Dynamic Model-Based Intelligent Nonsingular Terminal Sliding Mode Control for a Gantry Position Stage

A three-degree-of-freedom (3-DOF) dynamic model-based intelligent nonsingular terminal sliding mode control (INTSMC) system is proposed in this study for the precision contours tracking of a gantry position stage. A Lagrangian equation-based 3-DOF dynamic model for the gantry position stage is derived first. Then, to minimize the synchronous error and tracking error in the precision contours tracking, the 3-DOF dynamic model-based INTSMC system is proposed. In this approach, a nonsingular terminal sliding mode control is designed for the gantry position stage to achieve finite time tracking control. Moreover, to increase the robustness and to improve the control performance, an interval type-2 recurrent fuzzy neural network, and asymmetric membership function, which combines the advantages of interval type-2 fuzzy logic system, recurrent neural network, and asymmetric membership function, is developed as an estimator to approximate a lumped uncertainty. Finally, some experimental results of the gantry position stage for optical inspection application are obtained to show the validity of the proposed control approach.

Fault Tolerant Control of Aircraft Actuating Surfaces using Generalized DI and Integral SM Control

The paper introduces a new fault tolerant control structure against control surface failure, made by a combined use of Generalized Dynamic Inversion (GDI) control and Integral Sliding Mode control (ISMC). The null-control vector in the GDI-based control law parameterizes all the possible control functions that drive the aircraft trajectories to the sliding surface. A simple choice of the null-control vector is made, and is shown to yield closed-loop system stability for the nominal actuator scenario. The small gain theorem is employed to provide an explicit lower limit on the actuator efficiency matrix in the event of faults/failures. The efficacy of the proposed method in tolerating control surface actuator failure is demonstrated on the ADMIRE benchmark model.

Sliding-Mode Guidance and Control for All-Aspect Interceptors with Terminal AngleConstraints

In this paper, sliding-mode-control-based guidance laws to intercept stationary, constant-velocity, and maneuvering targets at a desired impact angle are proposed. The desired impact angle, which is defined in terms of a desired line-of-sight angle, is achieved in finite time by selecting the missile's lateral acceleration to enforce terminal sliding mode on a switching surface designed using nonlinear engagement dynamics. The conditions for capturability are also presented. In addition, by considering a three-degree-of-freedom linear-interceptor dynamic model and by following the procedure used to design a dynamic sliding-mode controller, the interceptor autopilot is designed as a simple static controller to track the lateral acceleration generated by the guidance law. Numerical simulation results are presented to validate the proposed guidance laws and the autopilot design for different initial engagement geometries and impact angles.

Traction Control Method of Hybrid Electric Vehicle based on Multi-Objective Dynamic Coordination Control

The control method of the conventional traction control system on split-μsurfaces improves vehicle acceleration performance, but influences its stability performance. To solve this problem, a hierarchical traction control system for ISG hybrid electric vehicles based on multi-objective dynamic coordination control (MHEVTCS) is proposed. In the upper level controller, a target driving torque calculating strategy based on dynamical sliding mode control is developed. In the lower level controller, such strategies as multi-objective dynamic coordination control strategy, brake torque control strategy based on an inverse model, target engine torque design strategy and torque dynamic coordinate control strategy are proposed. Detailed simulation and hardware-in-loop experiment results show that slipping wheels are controlled quickly, accurately and smoothly by MEHVTCS. MHEVTCS solves the problem of merely pursuing acceleration performance and neglecting stability performance of conventional traction control system.

Design of an Adaptive Terminal Dynamic Sliding Mode Controller for Anti-Ship Missiles

Adaptive dynamic sliding mode control strategy for the overload control of anti-ship missiles using Lyapunov stability theory is proposed. By using a function augmented sliding hyperplane, it is guaranteed that the output tracking error converges to zero in finite time. In addition, an adaptive method is adopted to attenuate the uncertainties. The simulation shows validity of the proposed method.

Adaptive estimator-based dynamic sliding mode control for the water level of nuclear steam generators

Steam Generator (SG) is a crucial component of nuclear power plant. The proper water level control of a nuclear steam generator is of great importance in order to secure the sufficient cooling source of the nuclear reactor and to prevent damage of turbine blades. The water level control problem of steam generators has been a main cause of unexpected shutdowns of nuclear power plants which must be considered for plant safety and availability. The control problem is challenging, especially at low power levels due to shrink and swell phenomena and flow measurement errors. Moreover, the dynamics of steam generator vary as the power level changes. Therefore, it is necessary to improve the water level control system of SG. In this paper, an adaptive estimator-based dynamic sliding mode control method is developed for the level control problem. The proposed method exhibits the desired dynamic properties during the entire output tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability. Simulation results confirm the improvement in transient response obtained by using the proposed controller.

Dynamic Sliding Mode Control of Air-to-Fuel Ratio in Internal Combustion Engines Using the Hybrid Extended Kalman Filter

The large modeling uncertainties and the nonlinearities associated with air manifold and fuel injection in spark ignition (SI) engines has given rise to difficulties in the task of designing an adequate controller for air-to-fuel ratio (AFR) control. Although sliding mode control approaches has been suggested, the inescapable time-delay between control action and measurement update results in chattering. This paper proposes the implementation of a nonlinear observer based control scheme incorporating the hybrid extended Kalman filter (HEKF) and the dynamic sliding mode control (DSMC). The results established upon the proposed methodology are given which demonstrate superior performance in terms of reducing the chattering magnitude.

On Chattering-Free Dynamic Sliding Mode Controller Design

For a class of linear MIMO uncertain systems, a dynamic sliding mode control algorithm that avoids the chattering problem is proposed in this paper. Without using any differentiator, we develop a modified asymptotically stable second-order sliding mode control law in which the proposed controller can guarantee the finite time convergence to the sliding mode and can show that the system states asymptotically approach to zero. Finally, a numerical example is explained for demonstrating the applicability of the proposed scheme.

Adaptive backstepping sliding mode control for feedforward uncertain systems

Output tracking backstepping sliding mode control for feedforward uncertain systems is considered in this article. Feedforward systems are not usually transformable to the parametric semi-strict feedback form, and they may include unmatched uncertainties consisting of disturbances and unmodelled dynamics terms. The backstepping method presented in this article, even without uncertainties differs from that of Ríos-Bolívar and Zinober [Ríos-Bolívar, M. and Zinober, A.S.I. (1999), ‘Dynamical Adaptive Sliding Mode Control of Observable Minimum Phase Uncertain Nonlinear Systems’, in Variable Structure Systems: Variable Structure Systems, Sliding Mode and Nonlinear Control, eds., K.D. Young and Ü. Özgüner. Ozguner, London, Springer-Verlag, pp. 211–236; Ríos-Bolívar, M., and Zinober, A.S.I. (1997a), ‘Dynamical Adaptive Backstepping Control Design via Symbolic Computation’, in Proceedings of the 3rd European Control Conference, Brussels]. In this article, the backstepping is not a dynamical method as in Ríos-Bolívar and Zinober (1997a, 1999), since at each step, the control and map input remain intact, and the differentiations of the control are not used. Therefore, the method can be introduced as static backstepping. Two different controllers are designed based upon the backstepping approach with and without sliding mode. The dynamic and static backstepping methods are applied to a gravity-flow/pipeline system to compare two methods.

Dynamical Integral Sliding Mode Control for Permanent Magnet Ring Torque Motor

In view of the characteristics of numerical control turntable servo system directly driven by permanent magnet ring torque motor, which is susceptible to load disturbance and parameter variation, a dynamic-integral sliding mode position controller is designed. Dynamic sliding mode control means making differential operation to switching function of conventional sliding mode control, thus, a new switching function can be obtained. The discontinuous terms are transferred to first or higher derivative of control quantity. Therefore, the dynamic sliding mode control law is continuous timely, and then the chattering can be effectively reduced. Meanwhile, in order to ensure the steady-state accuracy of system, the integral term is introduced in the switching function to realize dynamic integral sliding mode control. The simulation results indicate that dynamic-integral sliding mode control of permanent magnet ring torque motor has favorable dynamic response and strong robustness, and it is effective to weaken the chattering.

Missile acceleration controller design using proportional–integral and non-linear dynamic control design method

In this article, a method to make the normal acceleration of medium angle of attack missile to track some desired trajectories is presented. The dynamics which describe a missile acceleration are known to be non-minimum phase, which makes it difficult to use a straightforward feedback linearization technique. This article aims at showing that this problem may be overcome by employing cascaded regulations in the non-linear area. First, inner loop controller by dynamical sliding mode control (SMC) method based on asymptotic output tracking is designed for angle of attack control which has a minimum phase characteristics. Also then, the problem that is addressed here is the completion of the global loop by designing an additional outer loop proportional–integral (PI) controller and angle of attack estimator. The performance and stability of proposed method are illustrated via computer simulations.

Position Control of Servomotors Using Neural Dynamic Sliding Mode

In this paper, position control of servomotors is addressed. A radial basis function neural network is employed to identify the unknown nonlinear function of the plant model, and then a robust adaptive law is developed to train the parameters of the neural network, which does not require any preliminary off-line weight learning. Moreover, base on the identified model, we propose a new dynamic sliding mode control (DSMC) for a general class of nonaffine nonlinear systems by defining a new adaptive proportional-integral sliding surface and employing a linear state feedback. The main property of proposed controller is that it does not need an upper bound for the uncertainty and identified model; moreover, the switching gain increases and decreases according to the system circumstance by employing an adaptive procedure. Then, chattering is removed completely by using the DSMC with a small switching gain.

A Novel Sliding Mode Motion Control for Parallel Mechanism of Virtual Axis Machine Tool

This paper addresses the motion control of the parallel mechanism of virtual axis machine tool, which has a complex system model, the nonlinear and strong coupling characteristics and has strong external disturbances in high-speed machining. To further enhance its motion control performances, a novel adaptive dynamic sliding mode control method is proposed. The designed control system stability is proved theoretically. By building a new switching function, the second-order dynamic sliding mode control algorithm is designed to reduce the chattering of the conventional sliding mode control effectively and overcome the adverse effects of the fast changing dynamics of the actuators. By introducing the adaptive control, unknown external disturbances can be estimated online, which can improve the ability of resisting strong disturbances and the control precision of virtual axis machine tool. The simulation results for the virtual axis machine tool show that the designed control system has the good performances in tracking and resisting strong disturbances and can achieve the high precision motion control of the parallel mechanism of virtual axis machine tool.

Time-varying dynamic sliding mode control of a nonlinear aerospace launch vehicle

Tracking of guidance commands for nonlinear aerospace launch vehicles, ALV, during atmospheric flight is studied in dynamic sliding mode. Time-varying linearized dynamics of nonlinear ALV are achieved using small perturbations approach rendered into a regular form. A time-varying dynamic sliding mode controller is then designed by utilizing dynamic compensators for the linearized system at each moment to provide output tracking in presence of unmatched disturbances. Simulation results are conducted to demonstrate performance, robustness, and stability of the proposed autopilot.

Gain scheduled dynamic sliding mode control for nuclear steam generators

U-Tube Steam Generator (UTSG) is one of the most important facilities in a pressurized-water nuclear reactor. Poor control of the Steam Generator (SG) water level in the secondary circuit of a nuclear power plant can lead to frequent reactor shutdowns or damage of turbine blades. The control problem is challenging, especially at low power levels due to shrink and swell phenomena and flow measurement errors. In addition, the dynamics of steam generator vary as the power level changes. Therefore, designing a suitable controller for all power levels is a necessary step to enhance the plant availability factor. The purpose of this paper is to design, analyze and evaluate a water level controller for U-tube steam generators using dynamic sliding mode control. The employed method is easy to implement in practical applications and moreover, the dynamic sliding mode control exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Gain scheduling is used to obtain a global water level controller. Simulation results are presented to demonstrate the performance, robustness, and stability of the proposed controller. Computer simulations show that the proposed controller improves the transient response of steam generator water level and demonstrates its superiority to existing controllers.

An adaptive-dynamic sliding mode controller for non-minimum phase systems

This paper presents a new algorithm for designing dynamic sliding-mode controllers. The proposed controller is based on dynamic sliding manifolds to circumvent the difficulties associated with the conventional sliding mode controllers in the face of non-minimum phase systems. Unlike previous works, a proper and easy to implement algorithm is presented for designing the dynamic sliding manifold which facilitates the design of the controller. The output tracking problem in nonlinear non-minimum phase systems with matched and unmatched disturbances and matched nonlinearities is addressed. Then, the performance of the dynamic sliding mode controller is significantly improved by combining the given dynamic sliding manifold with online parameter adaptation. Simulations results are presented to demonstrate the effectiveness of the proposed sliding mode controller in terms of performance, robustness and stability.

Dynamic sliding mode control design using attracting ellipsoid method

A methodology for the design of sliding mode controllers for linear systems subjected to matched and unmatched perturbations is proposed. It is considered that the control signal is applied through a first-order low-pass filter. The technique is based on the existence of an attracting (invariant) ellipsoid such that the convergence to a quasi-minimal region of the origin using the suboptimal control signal is guaranteed. The design procedure is given in terms of the solution of a set of Matrix Inequalities. A benchmark example illustrating the design is given.

Dynamic integral sliding mode for MIMO uncertain nonlinear systems

In this paper the authors propose a novel sliding mode control methodology for Multi-Input and Multi-Output (MIMO) uncertain nonlinear systems. The proposed approach synthesizes dynamic sliding mode and integral sliding mode control strategies into dynamic integral sliding mode. The new control laws establish sliding mode without reaching phase with the use of an integral sliding manifold. Consequently, robustness against uncertainties increases from the very beginning of the process. Furthermore, the control laws considerably alleviate chattering along the switching manifold. In addition, the performance of the controller boost up in the presence of uncertainties. A comprehensive comparative analysis carried out with dynamic sliding mode control and integral sliding mode control demonstrates superiority of the newly designed control law. A chatter free regulation control of two uncertain nonlinear systems with improved performance in the presence of uncertainties ensures the robustness of the proposed dynamic integral sliding mode controller.