Sliding Mode Control System Research Articles

Active damping of sound transmission through an electrorheological fluid-actuated sandwich cylindrical shell

An exact model is proposed for sound transmission through a sandwich cylindrical shell of infinite extent that includes a tunable electrorheological fluid core, and is obliquely insonified by a plane progressive acoustic wave. The basic formulation utilizes Hamilton’s variational principle, the classical and first order shear deformation shell theories, the Kelvin–Voigt viscoelastic damping model (for the electrorheological fluid-core layer), and the wave equations for internal/external acoustic domains coupled by the proper fluid/structure compatibility relations. The Fourier–Bessel series expansions are used to arrange the governing (coupled) system equations in state-space form. The classical Sliding Mode Control law is then applied to semi-actively reduce sound transmission through the composite cylinder by smart variation of stiffness and damping characteristics of the electrorheological fluid-core actuator layer according to the control command. Numerical results present both the uncontrolled and controlled sound transmission loss spectra of the sandwich cylindrical shell at three angles of incidence for three distinct sets of material input parameters that represent the electric-field dependency of the complex shear modulus of the electrorheological fluid-core layer. The superior soundproof performance of electrorheological fluid-based sliding mode control system in avoiding the highly detrimental sound transmission loss dips occurring throughout the critical resonance and coincidence regions is demonstrated. Likewise, remarkable enhancements in the sound insulation characteristics of the electrorheological fluid-actuated structure utilizing the first or second electrorheological fluid material model are achieved within the stiffness-controlled region, especially at lower frequencies in near-grazing incidence situation. A number of limiting cases are introduced and validity of the formulation is confirmed by comparison with the available data.

Space Flyaround and In-orbit Inspection Coupled Control Based on Dual Numbers

In this paper, both the proportional derivative feedback control and variable-structure sliding mode control approaches based on dual numbers are presented to design space flyaround and in-orbit inspection missions. Dual-number-based spacecraft kinematics and dynamics models are formulated. The integrated translational and rotational motions can be described in one compact expression, and the mutual coupling effect can be considered. A space flyaround and in-orbit inspection mission model based on dual numbers is derived. Both proportional derivative feedback control and variable-structure sliding mode control laws are designed using dual numbers. Simulation results indicate that both the proposed control system can provide high-precision control for relative position and attitude. Of the two systems, the variable-structure sliding mode control system performs the best.

Adaptive fractional order sliding mode control for Boost converter in the Battery/Supercapacitor HESS.

In this paper, an adaptive fractional order sliding mode control (AFSMC) scheme is designed for the current tracking control of the Boost-type converter in a Battery/Supercapacitor hybrid energy storage system (HESS). In order to stabilize the current, the adaptation rules based on state-observer and Lyapunov function are being designed. A fractional order sliding surface function is defined based on the tracking current error and adaptive rules. Furthermore, through fractional order analysis, the stability of the fractional order control system is proven, and the value of the fractional order (λ) is being investigated. In addition, the effectiveness of the proposed AFSMC strategy is being verified by numerical simulations. The advantages of good transient response and robustness to uncertainty are being indicated by this design, when compared with a conventional integer order sliding mode control system.

Robust Genetic Algorithm and Fuzzy Inference Mechanism Embedded in a Sliding-Mode Controller for an Uncertain Underwater Robot

The integration of inaccurate remotely operated vehicle (ROV) model data obtained by computational fluid dynamics for control is presented. Since the ROV is highly nonlinear and uncertain, a sliding-mode control (SMC) system using a direction-based genetic algorithm (GA) and fuzzy inference mechanism is proposed. The GA influences the right evolutionary step and direction of the SMC parameters subjected to uncertainties in the evolutionary process. The effectiveness of reducing the sensitivity of the proposed control scheme to model parameters and external disturbance is verified by simulations and sea trial. The results demonstrate that the proposed controller performed better with less chattering in position responses than SMC without GA-fuzzy optimization, fuzzy logic controller, and proportional-integral derivative.

МОДЕЛИРОВАНИЕ СИСТЕМЫ УПРАВЛЕНИЯ В СКОЛЬЗЯЩЕМ РЕЖИМЕ АКТИВНЫМ ПРЕОБРАЗОВАТЕЛЕМ ТОКА

МОДЕЛИРОВАНИЕ СИСТЕМЫ УПРАВЛЕНИЯ В СКОЛЬЗЯЩЕМ РЕЖИМЕ АКТИВНЫМ ПРЕОБРАЗОВАТЕЛЕМ ТОКА

Vibration suppression in full car active suspension system using fractional order sliding mode controller

Vehicle active suspension systems (VASS) are designed to improve ride comfort and road handling capacity in the automotive industry. This paper investigates the problem of vibration suppression in full car model (FCM) with active suspension system (ASS) whose aim is to reduce the effect of the vibrations generated by road irregularities on the human body. The mathematical model is developed for seven degrees of freedom (DOF) FCM. The main objective is to control vibration of FCM for various road disturbances such as bump and random road disturbance using a fractional order sliding mode controller (FOSMC) and sliding mode controller (SMC). The effectiveness of the controllers are validated using MATLAB/Simulink software in terms of root mean square (RMS) values of body acceleration (BA), pitch acceleration (PA) and roll acceleration (RA). Further the power spectrum density (PSD) of BA is considered to show the human sensitivity range. The simulation results are indicated that FOSMC shows superior performance at adapting bump and random road disturbances compared to SMC and passive suspension system (PSS).

Twistor-based synchronous sliding mode control of spacecraft attitude and position

A synchronous control of relative attitude and position is required in separated ultra-quiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistor-based synchronous sliding mode control is investigated in this paper to solve the control problem of relative attitude and position among separated spacecraft modules. The twistor-based control design and the stability proof are implemented using the Modified Rodrigues Parameter (MRP). To evaluate the effectiveness of the proposed control method, this paper presents a case study of separated spacecraft flying control considering the mass uncertainty and external disturbances. In addition, a simulation study of the Proportional-Derivative (PD) control is also presented for comparison. The results indicate that the twistor-based sliding mode controller can ensure global asymptotic stability. The states converge fast with ultra-precision and ultra-stability in both the attitude and position. Moreover, the proposed twistor-based sliding mode control system is robust to the mass uncertainty and external disturbances.

지면효과를 갖는 쿼드로터에 대한 피드백 선형화기반 슬라이딩 모드 제어

The present invention relates to a sliding mode control system based on feedback linearization for a quad-rotor with a ground effect. The sliding mode control system may have posture maintenance and position control performance of a stable quad-rotor against disturbance such as a ground effect by a sliding mode control wherein a closed loop integral type is designed as a sliding plane.

Quantum sliding mode control via error sliding surface

In this paper, a new quantum sliding mode control, for improving the performance of the two-level quantum sliding mode control systems with bounded uncertainties, is introduced. The presented quantum sliding surface is based on the error which occurs between the predetermined sliding mode and the system state. The control objective is to derive the system state to reach the sliding mode domain and then maintain its motion on it. For this purpose, we use the sliding mode control method and periodic projective measurements. A theorem for facilitating the presented method is proved. The simulated example shows that both the reaching time to the sliding mode and the control amplitude are significantly decreased, which demonstrate the effectiveness and validity of the presented method.

Quasi-Continuous Second-Order Sliding Mode Control of Buck Converter

Aiming at the chattering problem of conventional sliding mode control systems for dc–dc converters, a quasi-continuous second-order sliding mode (QSOSM) control scheme for buck converters has been presented in the paper. It will be shown that the QSOSM controller is practically a continuous function of the states everywhere except the origin. And thus the chattering problem existing in conventional sliding mode can be practically solved due to the fact that the states cannot be stabilized to the origin from engineering point of view. Theoretical analysis also shows that the closed loop system of the buck converter is globally finite-time stable. Finally, the theoretical considerations have been verified by simulation and experimentation. Specifically, the comparisons between QSOSM controller and PID controller show that the former one provides a better robustness.

Sliding Mode Control for a Class of Positive Systems With Lipschitz Nonlinearities

This paper studies the sliding mode control (SMC) law design problem of a class of positive systems with Lipschitz nonlinearities. We aim to devise a proper SMC law to drive the sliding mode dynamics onto the designated sliding mode surface. By choosing proper Lyapunov functions, the positiveness and the asymptotic stability of the closed-loop SMC system are guaranteed by the presented sufficient conditions. The SMC law design problem can be solved by a linear matrix inequalities technique. In the end, the feasibility and the validity of the raised method are provided by the simulation results.

Full-order terminal sliding-mode control of MIMO systems with unmatched uncertainties

To control MIMO systems with unmatched uncertainties, two sliding-mode controllers are presented in this paper. Firstly, a terminal sliding-mode controller is presented to force the output of an MIMO system to a region near zero in finite-time. With the analysis on the effect of the unmatched uncertainties, a full-order terminal sliding-mode control is further proposed to force the output of the MIMO system to converge to zero rather than a region. The virtual control is utilized to establish the reference for the part of the system states, which can reject unmatched uncertainties completely. To generate continuous virtual control signals, the proposed full-order terminal sliding-mode controller makes the ideal sliding motion as the full-order dynamics rather than the reduced-order dynamics in traditional sliding-mode control systems. Finally, the simulations on the control of an L-1011 fixed wing aircraft at cruise flight conditions validate the effectiveness of the proposed method.

Design for Robust Aircraft Flight Control

A frequency-domain-based synthesis technique using pseudosliding-mode control has been previously introduced and exercised in the literature. The current research is aimed at presenting the design framework in a detailed, step-by-step fashion for use by those who may initially be unfamiliar with the robust flight control design methodology. The technique is exercised by designing a longitudinal flight control system for a model of a flexible aircraft. The resulting design is evaluated in a computer simulation that includes a model of the human pilot. Handling qualities predictions are included. To assess robustness, the simulations include abrupt variations in the characteristics of the aircraft control system and vehicle dynamics. A brief, human-in-the-loop tracking study is also undertaken to corroborate the results. Of particular relevance to the practicality of the design approach is the fact that no “adaptation” occurs (i.e., the sliding-mode control system elements remain invariant throughout).

Sliding-Mode Control of Four-Leg Inverter With Fixed Switching Frequency for Uninterruptible Power Supply Applications

In three-phase transformerless uninterruptible power supply applications, a four-leg inverter is an excellent solution to handle the full unbalanced loading condition. A sliding-mode control (SMC) system is well known for robustness, simple implementation, high stability, and suitable solution for variable structure systems like power converters. However, it suffers from the chattering problem, variable switching frequency, and high electromagnetic compatibility noises. In this paper, a high performance SMC system is proposed to control the output voltage of the four-leg inverter with fixed switching frequency. In the proposed SMC system, as a considerable achievement, not only chattering problem is reduced significantly, but also the robustness, regulation, and dynamic response of the SMC system are not affected. Also, the derivation and implementation of the proposed SMC is so simple with less current sensors and without high computational burden. Furthermore, fixed switching frequency offers remarkable simplicity of the converter and filter design. Several experimental results on a 3-kW test bench verify the superior performance of the proposed SMC system according to the IEC62040-3 standard.

Chattering Analysis of HOSM Controlled Systems: Frequency Domain Approach

In this article, a methodology of chattering analysis of Sliding Mode/Higher Order Sliding Mode (SM/HOSM) control systems in the frequency domain is presented. A numerical method for computing the Describing Functions (DFs) of HOSM control algorithms is given. The algorithm for predicted chattering parameters in dynamically perturbed system via the Describing Function-Harmonic Balance (DF-HB) technique is proposed. The stability conditions for limit cycles in dynamically perturbed HOSM control systems are presented. The concepts of Practical Stability Phase Margin ( PSPM ) and Practical Stability Gain Margin ( PSGM ) as the robustness metrics to unmodeled dynamics in HOSM control systems are introduced. The methodologies for computing PSPM and PSGM via DF-HB technique are provided. The accuracy of the proposed chattering analysis techniques is confirmed via computer simulations.

Data-Driven Robust Output Tracking Control for Gas Collector Pressure System of Coke Ovens

Disturbances, uncertainties, nonlinearity, couplings, and measurement disturbances exist extensively in the coke oven gas collector pressure system (GCPS) and may deteriorate tracking performance. In this paper, a practical method named data-driven robust output tracking control (DROTC) combining advantages of sliding-mode contr-ol (SMC) and data-driven control (DDC) is proposed for stable pressure control of gas collectors of coke ovens. Unlike the conventional DDC approach, the proposed controller is based on SMC framework, where a novel hybrid control structure and a new data-driven sliding surface are developed to facilitate the controller design. On one hand, the couplings, disturbances, and uncertainties are suppressed owing to the application of the SMC technique and the extended state observer. On the other hand, the stability of the DROTC system with bounded measurement disturbances could also be guaranteed by applying the DDC law. Moreover, the robustness could also be ensured once the sliding mode control system enters into the sliding mode. Finally, simulation and experimental results confirm the validity of the proposed control approach.

Reduction of Body Acceleration in the Quarter Car Model using Fractional Order Fuzzy Sliding Mode Controller

Vehicle vibration can be controlled by Active Suspension System (ASS). The performances of ASS are better than the conventional Passive Suspension System (PSS). The effectiveness of ASS is based on the type of controllers used. In this paper, a quarter car model with ASS is considered for analysis. To reduce the vibration and improve the ride quality, Fractional order Fuzzy Sliding Mode Controller (FrFSMC) is proposed and its performances are compared with Fuzzy Sliding Mode Controller (FSMC) and passive system. While testing the performance of the controllers three types of road disturbances are given to the quarter car model to stimulate the vibration. The results of the proposed controllers are also compared against the existing Gray Fuzzy Sliding Mode Controller (GFSMC). From the time responses and root mean square indices, FrFSMC performs better than the FSMC, GFSMC and PSS.

Second-order fuzzy sliding-mode control of photovoltaic power generation systems

In order to maximize the conversion efficiency of photovoltaic systems, it is usually essential to design a maximum power point tracking controller. In this paper, a new second-order fuzzy sliding-mode controller is designed for this purpose. Since the proposed scheme is based on the second-order sliding-mode control law, it can handle nonlinear dynamics of photovoltaic systems. Compared to previously introduced controllers, the proposed control law does not depend on model parameters and thus is robust to system uncertainties. The gain of the control signal is determined using a fuzzy gain tunning algorithm. Therefore, not only the robustness of the system will be improved, but also chattering amplitude will be suppressed. The proposed scheme does not require asymptotic observers, and thus its analysis and implementation are fairly simple. The performance of the proposed control system is verified through simulation and experiment. Compared to terminal sliding mode control system, the proposed system can increase the efficiency up to 1.5%.

Backstepping-Based Recurrent Type-2 Fuzzy Sliding Mode Control for MIMO Systems (MEMS Triaxial Gyroscope Case Study)

This paper presents a novel type-2 fuzzy sliding mode control with nonlinear consequent part in fuzzy rules for control of Micro-Electro-Mechanical Systems (MEMS) gyroscope. The MEMS gyroscope consists of the basic mechanical structure, an electronic transducer to excite the system as well as an electronic sensor to detect the change in the mechanical structures modal shape. A nonlinear consequent part recurrent type-2 fuzzy system is used to approximate the conventional sliding mode control (SMC) law. A supervisory compensator is introduced to eliminate the effect of the approximation error. The adaptive adjustment algorithms for type-2 fuzzy parameters are derived in the sense of projection algorithm and Lyapunov stability theorem. The proposed type-2 fuzzy system has simple structure with six layers. Recurrent feedbacks at the fifth layer uses delayed outputs for improve the performance of type-2 fuzzy system. Finally the proposed type-2 fuzzy sliding mode control system is used to tracking control design with regard to uncertainty in MEMS gyroscope system. Combination of backstepping method and sliding mode control helps to compensate the control signal and get a better performance. The backstepping method is used to improve the global ultimate asymptotic stability and applying the sliding mode control to obtain high response and invariability to uncertainties. Simulation results show the proposed type-2 fuzzy system has better performance than ANFIS-based sliding mode control.

Analysis of multiple oscillations in a sampling reduced-order sliding mode control in frequency domain

The phenomena of oscillations in sliding mode control system usually cause potential damage or danger in engineering applications. This paper focuses on the estimation and adjustment of oscillation parameters (frequency and amplitude) using an improved describing function method and the characterization of the influence of the reduced-order sliding surface coefficients on the performance of the nonlinear system. The model of series connection of the zero-order holder and switching function is established in frequency domain. The improved describing function method could intuitively estimate the number, stability and parameters of oscillations for the coupled nonlinear system by its amplitude-phase characteristics and pole placement. The stability, parameters and attraction zones of three oscillations in a fourth-order plant are analyzed and simulated. The analytical results show that the reduced-order sliding mode controller possesses complex and colorful nonlinear behaviors. Besides, a coefficient tuning method is presented to eliminate the undesired oscillation which may lead to poor precision or break the stability. The simulations demonstrate that appropriate tuning on sliding surface may greatly improve the efficiency and robustness of the sliding mode control system.