Mode Control In Order Research Articles

A new adaptive Perturb & Observe controller via robust approach for PV grid-connected

Given the importance of renewable energies, several countries are integrating these energies into their energy strategies, such as their connections to the grid, in particular photovoltaic energy. In this paper, a PV grid-connected system in a two-stage configuration is studied. In this configuration, an improvement to a control MPPT is proposed. To achieve this, we propose a novel concept for MPPT control that consists of generating an adaptive step size for P&O control that is based on sliding mode control in order to minimise ripple phenomena and chattering phenomena. The proposed control approach was then tested using MATLAB/Simulink simulations under varying irradiation conditions. We compared this approach to the conventional P&O method as well as the adaptive step size of P&O and hybrid P&O-sliding mode control. The results of the test indicate that the proposed control strategy significantly minimises the two phenomena and improves overall efficiency.

MAXIMUM POWER EXTRACTION USING TWISTING SLIDING MODE CONTROLLER FOR WIND ENERGY SYSTEMS

This paper presents a systematic control scheme for a wind energy conversion system with variable speed and describes a permanent magnet synchronous generator PMSG with five phases. The machine employs back-to-back converters, while the grid-side converters are used. Stator current and mechanical rotation speed control are employed to accomplish maximum power point tracking operation on the machine side converter at wind speed below the rated speed. The pitch of the angle is used to limit the extracted wind energy when the wind surpasses the specified wind. The grid current control loop regulates both active and reactive power injection at the unity power factor for the grid side converter. The five-phase PMSG rotor speed is controlled by the twisting sliding mode controller in order to maintain the reference speed in various wind speeds. Performance comparisons between the twisting sliding mode controller, conventional proportional integral controller, and integral sliding mode controller show that the twisting sliding mode controller is superior to the other controllers in steady state error. According to this study, the overall efficiency is increased to 94% when using the TSMC controller rather than the ISMC and PI controllers, which are currently at 92.45% and 88.12% respectively. MATLAB/Simulink simulation results are used to verify the effectiveness of the suggested control technique.

Stabilizing of Inverted Pendulum System Using Robust Sliding Mode Control

The Inverted Pendulum is a highly nonlinear, unstable, and fast dynamic system. These characteristics make it a popular benchmark for building and testing novel controllers. Therefore, in this study, a sliding mode controller is proposed and tested on the inverted pendulum system. According to the results of the simulation experiments with a sine signal as a reference, the proposed controller can stabilize the system well and has so fast response. Moreover, we have tuned the parameters of the proposed sliding mode controller in order to eliminate the chattering effect, the overshoot, and the steadystate error.

A fuzzy sliding mode control of anti-lock system featured by magnetorheological brakes: performance evaluation via the hardware-in-the-loop simulation

The aim of this work is to propose a new type of anti-lock braking system (ABS) using a magneto-rheological (MR) brake and validate its effectiveness by implementing a fuzzy logic sliding mode (FLSM) controller via the hardware-in-the-loop-simulation (HILS). Firstly, a quarter vehicle model integrated with the tire model is established to analyze control performance of MR brake during the braking process under different road conditions. Secondly, a disc type MR brake is designed on the basis of a mathematical model and the field-dependent braking torque is measured. Subsequently, in order to investigate the control performance of the proposed ABS, the software model is combined with the hardware configuration which is built by Matlab/Simulink. It is shown via HILS that the proposed ABS associated with the FLSM controller can provide high response speed and excellent braking control effect. In this work, control responses from the FLSM controller are also compared with those achieved from the conventional sliding mode controller in order to emphasize the significance of the control strategy to enhance ABS performances.

Adaptive backstepping sliding mode control with tuning functions for nonlinear uncertain systems

ABSTRACTAn adaptive backstepping tuning functions sliding mode controller is proposed for a class of strict-feedback nonlinear uncertain systems. In this control design, adaptive backstepping is used to deal with unknown or uncertain parameters and the matching condition restricting the Lyapunov based design. The main drawback of the Lyapunov based adaptive backstepping which is the overparametrisation is eliminated by the tuning functions. The adaptive backstepping tuning functions design is combined with the sliding mode control in order to overcome quickly varying parametric and unstructured uncertainties, and to obtain chattering free control. The proposed controller not only provides robustness property against uncertainty but also copes with the overparametrisation problem. Experimental results of the proposed controller are compared with those of the standard sliding mode controller. The proposed controller exhibits satisfactory transient performance, good estimates of the uncertain parameters, and less chattering.

An adaptive fuzzy sliding mode controller for uncertain underactuated mechanical systems

Underactuated mechanical systems are frequently encountered in several industrial and real-world applications such as robotic manipulators with elastic components, aerospace vehicles, marine vessels, and overhead container cranes. The design of accurate controllers for this kind of mechanical system can become very challenging, especially if a high level of uncertainty is involved. In this paper, an adaptive fuzzy inference system is combined with a sliding mode controller in order to enhance the control performance of uncertain underactuated mechanical systems. The proposed scheme can deal with a large class of multiple-input–multiple-output underactuated systems subject to parameter uncertainties, unmodeled dynamics, and external disturbances. The convergence properties of the resulting intelligent controller are proved by means of a Lyapunov-like stability analysis. Experimental results obtained with an overhead container crane demonstrate not only the feasibility of the proposed scheme, but also its improved efficacy for both stabilization and trajectory tracking problems.

GA/PSO Robust Sliding Mode Control of Aerodynamics in Gas Turbine

Abstract In gas turbine process, the axial compressor is subjected to aerodynamic instabilities because of rotating stall and surge associated with bifurcation nonlinear behaviour. This paper presents a Genetic Algorithm and Particle Swarm Optimization (GA/PSO) of robust sliding mode controller in order to deal with this transaction between compressor characteristics, uncertainties and bifurcation behaviour. Firstly, robust theory based equivalent sliding mode control is developed via linear matrix inequality approach to achieve a robust sliding surface, then the GA/PSO optimization is introduced to find the optimal switching controller parameters with the aim of driving the variable speed axial compressor (VSAC) to the optimal operating point with minimum control effort. Since the impossibility of finding the model uncertainties and system characteristics, the adaptive design widely considered to be the most used strategy to deal with these problems. Simulation tests were conducted to confirm the effectiveness of the proposed controllers.

Discrete-time sliding mode for building structure bidirectional active vibration control

In terms of vibrations along bidirectional earthquake forces, several problems are faced when modelling and controlling the structure of a building, such as lateral-torsional vibration, uncertainties surrounding the rigidity and the difficulty of estimating damping forces. In this paper, we use a fuzzy logic model to identify and compensate the uncertainty which does not require an exact model of the building structure. To attenuate bidirectional vibration, a novel discrete-time sliding mode control is proposed. This sliding mode control has time-varying gain and is combined with fuzzy sliding mode control in order to reduce the chattering of the sliding mode control. We prove that the closed-loop system is uniformly stable using Lyapunov stability analysis. We compare our fuzzy sliding mode control with the traditional controllers: proportional–integral–derivative and sliding mode control. Experimental results show significant vibration attenuation with our fuzzy sliding mode control and horizontal-torsional actuators. The proposed control system is the most efficient at mitigating bidirectional and torsional vibrations.

Switching PD-based sliding mode control for hovering of a tilting-thruster underwater robot.

This paper presents a switching PD-based sliding mode control (PD-SMC) method for the 6-degree-of-freedom (DOF) hovering motion of the underwater robot with tilting thrusters. Four thrusters of robot can be tilted simultaneously in the horizontal and vertical directions, and the 6-DOF motion is achieved by switching between two thruster configurations. Therefore, the tilting speed of thruster becomes the most essential parameter to determine the stability of hovering motion. Even though the previous PD control ensures stable hovering motion within a certain ranges of tilting speed, a PD-SMC is suggested in this paper by combining PD control with sliding mode control in order to achieve acceptable hovering performance even at the much lower tilting speeds. Also, the sign function in the sliding mode control is replaced by a sigmoid function to reduce undesired chattering. Simulations show that while PD control is effective only for tilting duration of 600 ms, the PD-based sliding mode control can guarantee the stable hovering motion of underwater robot even for the tilting duration of up to 1500 ms. Extensive experimental results confirm the hovering performance of the proposed PD-SMC method is much superior to that of PD method for much larger tilting durations.

Suppression of the noise-induced effects in an electrostatic micro-plate using an adaptive back-stepping sliding mode control

In this work, an adaptive backstepping sliding mode control approach is applied through the piezoelectric layer in order to control and to stabilize an electrostatic micro-plate. The mathematical model of the system by taking into account the small fluctuations in the gap considered as bounded noise is carried out. The accuracy of the proposed modal equation is proven using the method of lines. By using both approaches, the effects of noise are presented. It is found that they lead to pull-in instability as well as to random chaos. A suitable backstepping approach to improve the tracking performance is integrated to the adaptive sliding mode control in order to eliminate chattering phenomena and reinforce the robustness of the system in presence of uncertainties and external random disturbances. It is proved that all the variables of the closed-loop system are bounded and the system can follow the given reference signals as close as possible. Numerical simulations are provided to show the effectiveness of proposed controller.

Robust Generation of Self-Oscillation in Pendulum Systems: A switched Integral Sliding Mode Control Approach

A two relay controller is robustified by a switched integral sliding mode controller in order to generate robust self-oscillations for pendulum systems. The proposed strategy assures theoretically exact robustification of the self-oscillations preserving the amplitude and frequency of the oscillations even in the presence of matched uncertainties/perturbations. The efficiency of the proposed robustifying approach is illustrated on an example of a Furuta pendulum.

Assumed model feedforward sliding mode control for a wheeled mobile robot with 3-DOF manipulator systems

In this paper, a three wheeled mobile platform with a 3-DOF manipulator was designed and its dynamic model has been constructed and a Sliding mode control (SMC) with the kinematic control is designed to follow the designed position trajectory for a mobile manipulator. Next, an assumed dynamic model of each system is used to design sliding mode controller in order to replace the modelbased control and adaptive estimation for unknown dynamic parameters. The stability of the proposed control scheme has been proved by Lyapunov theory. The effectiveness and accuracy of the proposed algorithm has been verified by simulations and practical experiments for the developed mobile manipulator system. And the simulation and experimental results have been compared to those of traditional PID algorithm to show the superiority of the proposed algorithm.

Maximum Power Point Tracking of Wind Energy Conversion System Using Multi-objective grey wolf optimization of Fuzzy-Sliding Mode Controller

Ongoing electricity demand and the increasing growth of population have become necessary to provide alternative and clean sources of energy. Wind energy is one of the most important sustainable energies but the irregular characters of the primary source, which is characterized by a random wind speed variation, makes the process of control is difficult in order to maximize the power. This paper presents a multi objective grey wolf optimization (MOGWO) of fuzzy sliding mode controller in order to maximize the power captured by wind turbine; meanwhile, the mechanical loads are alleviated for variable speed wind energy conversion system (VS-WECS); firstly, Fuzzy logic theory based sliding mode control is developed by collecting the sliding surface data to reduce the chattering effect caused by the SMC, then the Grey Wolf Optimization is introduced to solve multi-objectives functions of WECS which are extracting the maximum power and alleviation the mechanical loads in order to find the optimal parameters of Fuzzy-Sliding mode controller to drive the conversion system to the optimal operating point. The obtained results are compared with those given by Sliding mode controller and Fuzzy-Sliding mode controller in which our proposed method can ensure a better dynamic behavior of the WECS.

Fuzzy Sliding Mode Control for Photovoltaic System

In this study, a fuzzy sliding mode control (FSMC) based maximum power point tracking strategy has been applied for photovoltaic (PV) system. The key idea of the proposed technique is to combine the performances of the fuzzy logic and the sliding mode control in order to improve the generated power for a given set of climatic conditions. Different from traditional sliding mode control, the developed FSMC integrates two parts. The first part uses a fuzzy logic controller with two inputs and 25 rules as an equivalent controller while the second part is designed for an online adjusting of the switching controller’s gain using a fuzzy tuner with one input and one output. Simulation results showed the effectiveness of the proposed approach achieving maximum power point. The fuzzy sliding mode (FSM) controller takes less time to track the maximum power point, reduced the oscillation around the operating point and also removed the chattering phenomena that could lead to decrease the efficiency of the photovoltaic system.

Design and Simulation of Sliding Mode Fuzzy Controller for Nonlinear System

Sliding Mode Controller (SMC) is a simple method and powerful technique to design a robust controller for nonlinear systems. It is an effective tool with acceptable performance. The major drawback is a classical Sliding Mode controller suffers from the chattering phenomenon which causes undesirable zigzag motion along the sliding surface. To overcome the snag of this classical approach, many methods were proposed and implemented. In this work, a Fuzzy controller was added to classical Sliding Mode controller in order to reduce the impact chattering problem. The new structure is called Sliding Mode Fuzzy controller (SMFC) which will also improve the properties and performance of the classical Sliding Mode controller. A single inverted pendulum has been utilized for testing the design of the proposed controller. Programming and Simulink by Matlab have been used for the simulation results.
 

Photovoltaic Water Pumping System Controlled by Cascade Sliding Mode

This study presents a new maximum power point tracking algorithm applied to a photovoltaic water pumping system in order to optimize the photovoltaic power generation. This system is driven by an induction motor controlled by a cascade sliding mode control in order to track a set of reference trajectories such as currents, rotor flux and speed. By using the MATLAB-SIMULINK software, modeling and simulation studies are investigated to highlight the utility of the proposed system.

Robust exponential stabilisation of a class of nonlinear systems using a novel technique of higher order sliding mode control

In this work, we propose a novel technique of higher order sliding mode control in order to solve the problem of chattering phenomenon which appears, generally, with standard sliding mode controller. The proposed approach provides an exponential stability on the sliding surface and guarantees the robustness of the closed loop system against uncertainties and external matched disturbances. The resulting controller has been applied to control an induction motor. Numerical simulations are developed to show the effectiveness of the proposed approach.

Backstepping Sliding Mode Control for Rocket Launcher Alternating Current Servo System

Aiming at wide variations in loads and moment of inertia, large disturbed moment of a rocket launcher position servo system, a backstepping sliding mode control method was present. The proposed method combines the backstepping control with the classical sliding mode control in order to limit the matched disturbances and the unmatched disturbances , which are caused by the gas flow impact and the moment of inertia disturbance respectively. The simulation results show that the proposed approach can guarantee accuracy and increase the response speed and possesses a strong robustness to the matched disturbances and the unmatched disturbances.

An optimal approach to synchronize non‐identical chaotic circuits: An experimental study

AbstractThe control signal magnitude and energy are among the limiting and therefore important factors to be addressed in the practical applications of a synchronization scheme. In this paper, we present an algorithm to find control parameters in an active sliding mode controller in order to reduce the control effort in synchronizing non‐identical chaotic systems. We also determine uncertainties bound on the systems dynamics for which the calculated control parameters still guarantee the occurrence of the sliding motion of the error states. The proposed controller was practically applied on an experimental setup, consisting of two chaotic circuits, which resembles Chen and Lu systems behavior. Experimental results confirm our theoretical reasoning as well as the effectiveness of the proposed control design technique. Copyright © 2010 John Wiley & Sons, Ltd.

INTELLIGENT BRAKING SYSTEM USING FUZZY LOGIC AND SLIDING MODE CONTROLLER

In this paper, an antilock–antiskid braking system controller, which has been designed for stability enhancement of vehicles during braking and turning, is presented. Using available signals, a novel structure is proposed for vehicle stability improvement for critical driving conditions such as braking on slippery or µ-split road surfaces. In conventional vehicles, undesired lane changes may occur due to equal dispatch of braking torques to all wheels simultaneously. Also, intensive pressure on brake pedal can bring about wheel lockup which results in vehicle instability and undesired lane changes. Antilock braking system (ABS) along with Antiskid braking system (ASBS) can serve as a driver-assistance system in vehicle path correction facing critical driving conditions during braking and turning round on different road surfaces. For these purposes, at first, a trained Neuro-Fuzzy estimator is used for vehicle path prediction according to vehicle’s speed, applied steering angle and their changes. Then, slip of each wheel will be controlled by an antilock fuzzy controller which has been designed for each wheel. Also, a sliding mode controller has been designed so as to control the yaw angle considering the yaw error, where the yaw error is resulted from the difference of the Neuro-Fuzzy estimator’s output and actual yaw angle. Then, the difference of the left and the right wheels’ braking torques are used by the sliding mode controller in order to reduce the yaw error. Considering a model of three-degreeof-freedom for chassis and one-degree-of-freedom Dugoff’s tire model for each wheel, a series of Matlab/Simulink simulation results will be presented to validate the effectiveness of the proposed controller. Finally, a comparison will be made between the proposed method and one of the recent control systems which shows the superiority of its performance.