Methodologies of chattering attenuation in sliding mode controller

Uncertain or complicated systems are difficult to control. Modeling the system uncertainties is an especial topics in most of engineering field. On the other hand, since system has uncertainty, design stable and robust controller is crucial importance in control engineering. To solve this challenge nonlinear control technique is the best choice. Sliding mode control is one important type of robust control. Model imprecision may come from actual uncertainty about the plant or from a purposeful simplification of the system's dynamics. Modeling inaccuracies can cause strong adverse effects on the control design of nonlinear systems. For the class of systems to which it applies, sliding mode controller design provides a systematic approach to the problem of maintaining stability and consistent performance in the face of modeling imprecision. However, sliding mode controller is a robust and stable controller but it has an important challenge called, chattering phenomenon. This research focuses on the comparative between three methods to eliminate/reduce the chattering

Avoidance High-Frequency Chattering Second-Order Sliding Mode Controller Design: Buck Converter in Wind Power System

This paper mainly discussed a method of high-frequency second-order sliding mode control for Buck converter in wind power systems. Because the wind energy of nature is always unpredictable and intermittent, the robust control such as sliding mode control is adopted in past literatures. In order to remove the high frequency chattering problem when the traditional sliding mode achieves convergence, the second order sliding mode algorithm is reviewed firstly. Meanwhile, the Buck converter taken as a step-down converter is usually adopted in wind power system, because of its simple structure and good linearity. Under those conditions, the second order sliding mode controller is designed based on Buck converter, especially in high-power wind generation system. The experimental results illustrate that the theory of second order sliding mode can be used in high-power Buck converter. It provides one novel avoidance high frequency chattering method for the technology development of new energy generation system

Discrete Adaptive Second Order Sliding Mode Controller Design with Application to Automotive Control Systems with Model Uncertainties

Sliding mode control (SMC) is a robust and computationally efficient solution for tracking control problems of highly nonlinear systems with a great deal of uncertainty. High frequency oscillations due to chattering phenomena and sensitivity to data sampling imprecisions limit the digital implementation of conventional first order continuous-time SMC. Higher order discrete SMC is an effective solution to reduce the chattering during the controller software implementation, and also overcome imprecisions due to data sampling. In this paper, a new adaptive second order discrete sliding mode control (DSMC) formulation is presented to mitigate data sampling imprecisions and uncertainties within the modeled plant's dynamics. The adaptation mechanism is derived based on a Lyapunov stability argument which guarantees asymptotic stability of the closed-loop system. The proposed controller is designed and tested on a highly nonlinear combustion engine tracking control problem. The simulation test results show that the second order DSMC can improve the tracking performance up to 80% compared to a first order DSMC under sampling and model uncertainties.Comment: 6 pages, 6 figures, 2017 American Control Conferenc

Design of robust Higher Order Sliding Mode control for microgrids

This paper deals with the design of advanced control strategies of sliding mode type for microgrids. Each distributed generation unit (DGu), constituting the considered microgrid, can work in both grid-connected operation mode (GCOM) and islanded operation mode (IOM). The DGu is affected by load variations, nonlinearities and unavoidable modelling uncertainties. This makes sliding mode control particularly suitable as a solution methodology for the considered problem. In particular, a second order sliding mode (SOSM) control algorithm, belonging to the class of Suboptimal SOSM control, is proposed for both GCOM and IOM, while a third-order sliding mode (3-SM) algorithm is designed only for IOM, in order to achieve, also in this case, satisfactory chattering alleviation. The microgrid system controlled via the proposed sliding mode control laws exhibits appreciable stability properties, which are formally analyzed in the paper. Simulation results also confirm that the obtained closed-loop performances comply with the IEEE recommendations for power systems

DESAIN AKSI KENDALI PID PADA PERMUKAAN LUNCUR DECOUPLE SLIDING MODE CONTROLLER PADA SISTEM NON LINIER MULTIVARIABEL CONTINUOUS STIRRED TANK REACTOR (CSTR)

These study proposed of level controlling and concentrate on non- linear multivariable CSTR systems . The main problem was the presence of the coupled system and the Error Steady State ( ESS ) which caused of system instability . The problem of coupled system has been solved with decouple design . Meanwhile, the problems of steady-state error ( ESS ) was completed with the election of a sliding mode controller ( SM ) . The selection of sliding mode controllers based on their solidity toward interference . However , the sliding mode controller has the disadvantage which was chattering that caused the Error Steady State. To overcome these shortcomings, the PID control action was designed on a sliding surface of sliding mode control. From the research results obtained concluded that the sliding mode controller with PID sliding surface could reduce the ESS from -0.0002 to -0.0200 in level and 0.0106 to 0,0008 in concentration .Keywords : Chattering , CSTR , Steady State Error , PID , Sliding Mode

Discretized bounded sliding mode control for simulation of differential-algebraic systems

Sliding mode control has recently proved to be a highly effective method for state space modeling of differential-algebraic equation systems (DAEs). Sliding control realizations have great potential for simulation since they allow more computationally efficient robust modeling approximations to be constructed for DAE systems. However, efficient discretization of such methods poses a significant problem due to the well known chattering phenomena that often occurs due to limited computational bandwidth. While some errors are inevitable due to limited bandwidth, the chattering phenomenon can be reduced by minimizing the frequency at which the system crosses the sliding surface. In this work, we find relations between controller parameters, error bounds, and the crossing frequency. They are then used to synthesize efficient discretized sliding mode realizations that optimize crossing frequency and the associated controller sampling period. Together, these results form an efficient discretized bounded sliding mode control approach for simulation of differential-algebraic systems

Multivariable Sliding Mode Control Design for Aircraft Engines

Many control theories are used in controlling aircraft engines. However, the multivariablesliding mode control is not yet established in this application even though ithas a lot of potential in dealing with complex and nonlinear systems such as aircraftengines. Therefore, a guideline in developing multivariable sliding mode control law for an aircraft engine is presented in this thesis. The problem of chattering in thesliding mode control is suppressed by the use of the boundary layer method. The controllogic is tested by implementing NASA\u27s Commercial Modular Aero-PropulsionSystem Simulation 40k (C-MAPSS40k). Simulation results are analyzed and comparedto the results obtained from the baseline controller. The robust property of multivariable sliding mode control is also examined by altering the flight condition ofthe engin

Multivariable Sliding Mode Control Design for Aircraft Engines

Many control theories are used in controlling aircraft engines. However, the multivariablesliding mode control is not yet established in this application even though ithas a lot of potential in dealing with complex and nonlinear systems such as aircraftengines. Therefore, a guideline in developing multivariable sliding mode control law for an aircraft engine is presented in this thesis. The problem of chattering in thesliding mode control is suppressed by the use of the boundary layer method. The controllogic is tested by implementing NASA\u27s Commercial Modular Aero-PropulsionSystem Simulation 40k (C-MAPSS40k). Simulation results are analyzed and comparedto the results obtained from the baseline controller. The robust property of multivariable sliding mode control is also examined by altering the flight condition ofthe engin