Classical Sliding Mode Control Research Articles

Characterization and Designing Integral Sliding Mode Controller for 2-Link Robot System with Coulomb Friction

The indemnification of uncertainty and disturbance which is added to non-linear systems by an Integral Sliding Mode Controller (ISMC) design. the key target of this paper is designing a sturdy controller to observe the performance of a 2-link robot. The nonlinearity in mechanical systems is a shared issue that the researchers are facing in formulating control systems for it. The best solution to this problem is a design Sliding Mode Controller (SMC) for controlling a nonlinear system. In the current paper, 2-link robot is studied which suffering from disturbances and parameter uncertainty and coulomb friction as additional to friction inertia of the system for each link. firstly, Classical Sliding Mode Controller (CSMC) is designed and then Integral Sliding Mode Controller (ISMC). As known, CSMC includes two phases: reaching phase and sliding phase. SMC is suffering from the known phenomenon as "chattering" which is supposed as a critical case and unsuitable characteristic. chattering is described as a curvy movement span the switching surface. In the current study, the chattering is attenuated by employing a saturation function alternative of a sign function. Although SMC can be considered as a good way of controlling nonlinear systems. Where it continues to suffer from the long settling time as undesired features. ISMC is a good method can be employed for reducing the settling time and controlling a nonlinear system. ISMC is easy, robust execution and supposes as an active and strong technique. The most significant advantage in ISMC designing, the reaching phase is canceled that considered a major part of designing classical SMC. The 2 link Robot system was used for proving the performance of CSMC and ISMC algorithms. The outcomes received from the simulations utilizing the ISMC and CSMC which fulfilled asymptotic stability for the system. In comparative between CSMC and ISMC. ISMC is better than CSMC in the good performance of tracking the desired position with less time. Finally, MATLAB2019a software package has relied upon this work.

Robust Wheel Slip for Vehicle Anti-lock Braking System with Fuzzy Sliding Mode Controller (FSMC)

Anti-lock Braking System (ABS) is used in automobiles to prevent slipping and locking of wheels after the brakes are applied. Its control is a rather complicated problem due to its strongly nonlinear and uncertain characteristics. The aim of this paper is to investigate the wheel slip control of the ground vehicle, comprising two new strategies. The first strategy is the Sliding Mode Controller (SMC) and the second one is the Fuzzy Sliding Mode Controller (FSMC), which is a combination of fuzzy logic and sliding mode, to ensure the stability of the closed-loop system and remove the chattering phenomenon introduced by classical sliding mode control. The obtained simulation results reveal the efficiency of the proposed technique for various initial road conditions.

Control of a Single Stage Boost Inverter Based on Dynamic Sliding Mode Control with Power Decoupling

In this paper, the problem of control a single-stage boost inverter is studied. The goal is to achieve a system with robustness against variations in parameters, fast response, high-quality AC voltage, and smooth DC current. To this end, a new type of dynamic sliding mode control is proposed to apply to various scenarios such as parameter uncertainties and DC input voltages. In comparison with the conventional double-loop controllers, the proposed sliding mode controller utilizes only a single loop in its design, while having attractive features such as robustness against parametric uncertainties. In addition, a methodology is proposed for the decoupling of double-frequency power ripples based on proportional-resonant (PR) control to remove the low-frequency current ripples without using additional power components. Compared to conventional controllers, the proposed controller provides several features such as fast and chattering-free response, robustness against uncertainty in the parameters, smooth control, proper steady-state error, decoupled power and good total harmonic distortion (THD) over the output voltage and input currents, and simple implementation. In a fair comparison with classical sliding mode control, simulation results demonstrate more satisfactory performance and effectiveness of the proposed control method.

Novel algebraic meal disturbance estimation based adaptive robust control design for blood glucose regulation in type 1 diabetes patients.

This study designs a robust closed-loop control algorithm for elevated blood glucose level stabilisation in type 1 diabetic patients. The control algorithm is based on a novel control action resulting from integrating algebraic meal disturbance estimator with back-stepping integral sliding mode control (BISMC) technique. The estimator shows finite time convergence leading to accurate and fast estimation of meal disturbance. Moreover, compensation of the estimated disturbance in controller provides significant reduction in chattering phenomenon, which is inherent drawback of sliding mode control (SMC). The controller is applied to one of the most reliable models of type 1 diabetic patients, named Bergman's minimal model. The effectiveness and superiority of the designed controller is shown by comparing it to classical SMC and super-twisting sliding mode control. The designed controller is subject to three different cases for detailed analysis of the controller's robustness against meal disturbance. The three cases considered are hyperglycaemia, hyperglycaemia combined with meal disturbance and three meal disturbance. The simulation results confirm superior performance of algebraic disturbance estimator based BISMC controller for all the cases mentioned above.

Experiential Integral Backstepping Sliding Mode Controller to achieve the Maximum Power Point of a PV system

Maximum Power Point Tracking (MPPT) strategy is necessary to extract the maximum power production of a Photovoltaic (PV) system. Since the PV has nonlinear dynamics, it is more suitable to use a nonlinear MPPT controller to improve the tracking efficiency. The modelling and control of most systems in real-time are not fully precise and introduce some variations such as : the steady state error and ripples in the system outputs. In this paper, a classical sliding mode controller has been designed and applied experimentally to the PV system to achieve the Maximum Power Point (MPP). The results show that the system responses present chattering phenomena with no negligible state error. In order to reduce these drawbacks (chattering and steady-state error), an Integral Backstepping combined with a discontinuous Sliding Mode Controller (IBSMC) is proposed and applied experimentally to the PV system. The obtained experimental results for the two controllers are compared under the same weather conditions, in terms of chattering phenomena and state error. As a result, the proposed hybrid controller (IBSMC) has achieved high dynamic system performances. Moreover, the stability of this system has been proved using Lyapunov stability criteria.

Epilepsy control using a fixed time integral super twisting sliding mode control for Pinsky–Rinzel pyramidal model through ion channels with optogenetic method

Background and ObjectiveEpilepsy is a dynamic disease of neuronal networks and epileptic activity in the brain should be suppressed quickly in the shortest possible time with minimum control signal. Thus, a closed-loop feedback control by using the fixed-time integral super-twisting sliding-mode controller via an optogenetic method is employed for suppressing seizures in the Pinsky–Rinzel (PR) model as a dynamic model of the hippocampus CA3 region where epileptic seizures occur. The control signal is applied to the PR model through the ChR2 channel model in the form of light photons using the optogenetic method. The present study aimed to determine the controller robustness against parameter changes and disturbances in order to reduce the control time, approach the zero tracking error of the normal desired state in a fixed time, and finally, converge the epileptic state to the normal desired state. MethodIn order to apply the control signal to the Pinsky–Rinzel model in the optogenetic method, the dynamic model of the ion current generated by channelrhodopsin 2 (ChR2) as a light-sensitive protein model in the optogenetic method was first applied to the PR model. Then, a fixed-time integral super-twisting sliding-mode controller was designed for the system, which is the combination of PR and ChR2 models. ResultsAfter applying the proposed controller, the simulation results indicated that the control signal was −0.7 mV, the tracking error of the normal desired state could reach zero within 1.5 milliseconds, and the problems of singularity and chattering were solved. ConclusionsA reduction occurred in the control signal reduced regarding the objectives of the study and comparing the proposed controller with the classical sliding-mode controller. Thus, this method can produce a safe control input for brain. In addition, both types of sliding mode controllers are robust against the parameters variations and external disturbances. Thus, they are superior to non-robust and simple controllers. Finally, based on the results, the validity of the fixed-time integral super-twisting sliding mode controller is confirmed for epilepsy control.

Performance of the adaptive sliding mode control scheme for output voltage control of the DC/DC buck converter system

In this work, the DC output voltage of a step-down DC/DC buck converter system has been controlled using different schemes of sliding mode controllers (SMCs) such as classical sliding mode controller (CSMC), modified sliding mode controller (MSMC) and the adaptive sliding mode controller (ASMC). As the DC/DC buck converter is a nonlinear and time-variant system, the application of linear control techniques for controlling this type of converters is not always suitable. Therefore, the SMCs are used here due to their characteristic features of maintaining the overall system stability with acceptable performance in the absence or presence of the parameters uncertainty and external disturbance. The simulation results obtained using MATLAB/Simulink software show the advantages of using ASMC in terms of reducing the settling time, the chattering value in the control action and the steady state error but the hitting time is increased when compared with the CSMC. Besides, the simulation results show the advantages of using ASMC in terms of reducing the settling time and the chattering value, but the steady state error and the hitting time are increased when compared with the MSMC. Since the buck converter is a fast response system, the performance of the ASMC is better than that of the CSMC and MSMC in terms of reducing the settling time and the chattering value in the control action.

Higher order sliding mode STATCOM control for power system stability improvement

The objective of this research is to design a higher order Sliding Mode Controller (SMC) for a Static Synchronous Compensator (STATCOM) and investigation of its implication on power system stability improvement. The theory of Super-Twisting–Sliding-Mode-Control (STSMC) is applied to determine the nonlinear control law of a STATCOM. The STSMC based control combines 2-sliding control and Robust Exact Differentiator (RED) which can efficiently mitigate the effect of external disturbance to the system The purpose of the application of the STSMC based control method is that it not only solves the chattering problem of classical SMC but also the derived control law is independent of system parameters. The efficacy of the design of the proposed STATCOM controller has been investigated in comparison to both the nonlinear (via exact linearization) and conventional (via approximate linearization) Linear Quadratic Regulator (LQR) based STATCOM controller. An IEEE type 14 bus multi-machine system has been taken into consideration to study the simulation results with regard to the transient stability improvement in multiple operating scenarios. It has been revealed from the simulation results that the proposed control scheme based on STSMC is more effective with respect to both the exact linearization based as well as approximately linearization based approach for the design of STATCOM controller. Furthermore, it has been abstracted that the STSMC based nonlinear STATCOM controller is competent to mitigate the dynamic instability of an electric power system even under contingency and different loading conditions.

Robust Controller Design for Flexible Joint Based on Back-Stepping Approach

The objective of this paper is to design a robust controller for a system modeled as a two-mass system, with a flexible coupling. Here, the flexible Joint between two-mass systems is characterized by a spring. In fact, a two-mass system represents most of an industrial drive, like rolling mill drives, automated arms, conveyor belts, and so on, that has a flexible joint, for which oscillation suppression and robust control against model uncertainties and external disturbances are very important. The proposed controller is based on sliding mode control with a back-stepping approach. Two subsystems (upper and lower) strategies are proposed for two- mass systems. On this basis, the classical sliding mode controller for each subsystem based on Lyapunov stability theory and sliding mode control theory is addressed to eliminate the influences of the parametric uncertainties, nonlinearities, and external disturbance load with the aid of sliding mode perturbation observer. Finally, comprehensive simulations are conducted to demonstrate the excellent performance of the proposed method.

Design of PWM-SMC Controller Using Linearized Model for Grid-Connected Inverter With LCL Filter

Nowadays, various sliding-mode control (SMC) methods have been successfully applied to the digitally controlled grid-connected inverter (GCI) with an LCL filter. However, how to design the pulsewidth modulation based SMC (PWM-SMC) controller needs to be further explored, especially upon the large variation of the parameters drift and the delay issue. In this article, the essence of two classic SMC methods used in the power converter area is first analyzed in detail. Thus, a novel design of the PWM-SMC controller using a linearized model for the three-phase GCI with an LCL filter is proposed. Based on this, a three-loop step-by-step design of the PWM-SMC controller is developed, by using the closed-loop pole locations. A robust analysis against the parameters drift is also studied. In addition, a discrete state observer is adopted to reduce the number of sensors. Furthermore, a discussion between the proposed control strategy with the existing SMC methods and the full-state feedback controller is carried out. Finally, a 3-kW lab device designed on the dSPACE is constructed to verify the feasibility of the proposed strategy and the correctness of the theoretical analysis.

Active vibration reduction system with mass damper tuned using the sliding mode control algorithm

The paper aims at evaluating the sliding mode control parameters used to tune a dynamic damper in the vibration reduction system. The effectiveness of the presented vibration reduction system and the power of the controlled voltage source supplying an electrodynamic linear motor have been analysed. The classical sliding mode control algorithm has been modified based on the analyses of results of calculation. The operation of the modified algorithm has been checked during a simulation. The proposed vibration reduction system was implemented on a laboratory stand. The measurement results have confirmed the effectiveness of the considered system.

Three degrees of freedom rotary double inverted pendulum stabilization by using robust generalized dynamic inversion control: Design and experiments

The aim of this article was to determine control strategy for balance control of rotary double inverted pendulum system, which is highly nonlinear and unstable under-actuated system. The complexities involved in rotary double inverted pendulum dynamics make this system a useful engineering test bed to test and verify newly designed controllers. In this article, a constraint-based control approach titled robust generalized dynamic inversion is designed and implemented for robust stabilization of rotary double inverted pendulum system. The robust generalized dynamic inversion control is designed in two stages; in the first stage, constraint differential equations of the controlled state variables are prescribed, which encompasses the control objectives. To enforce the constraint dynamics, the equivalent control is realized by means of Moore–Penrose generalized inversion. To enhance robustness, the switching (discontinuous) control is introduced in second stage, whose design principle is based on classical sliding mode control theory. Finally, the controllers obtained in two stages are augmented to form the resultant robust generalized dynamic inversion control law. The proposed controller ensures robustness along with improved time domain performance regardless of system nonlinearities, uncertainties, and unwanted disturbances. The stability analysis is presented for guaranteeing semi-global asymptotically stable closed loop performance via Lyapunov stability criteria. Numerical simulation and experimental investigations are carried out along with comparative analysis, to demonstrate the effectiveness of robust generalized dynamic inversion control algorithm over other conventional control methods.

Continuous sliding mode control for gun position servo system

With the development of military technology and changes in the war situation, modern warfare has higher requirements for the accuracy and speed of gun firing. The control performance of the gun position servo system directly affects the accuracy and speed of the gun firing. In order to improve performance of the gun, the sliding mode control is investigated for the gun position servo system. Sliding mode control has advantages of simple structure and good robustness against uncertain system parameters and disturbance. But discontinuous sign function in the classical sliding mode control method will lead to chattering of the system. To address the shortcoming of chattering in the traditional sliding mode control, a continuous sliding mode control algorithm is investigated in this paper. Finally, numerical simulations are performed to illustrate the efficiency of the theoretical results.

Highly maneuvering target interception via robust generalized dynamic inversion homing guidance and control

The Robust Generalized Dynamic Inversion (RGDI) homing guidance (HG) and control design methodology is proposed for intercepting highly maneuvering targets. The two-loops RGDI based system is designed by prescribing dynamic constraints that encapsulate the interception kinematic and dynamic objectives. The constraints are generalized-inverted using the dynamically scaled Moore-Penrose Generalized Inverse to solve for the HG and control variables. Sliding mode control (SMC) elements are augmented in the two loops, and are aimed to equip the closed loop RGDI system with a guaranteed semi-global practically stable tracking performance and robustness against tracking performance degradation due to modeling and parametric uncertainties, exogenous disturbances, and generalized inversion scaling. Numerical simulations of the RGDI system are conducted using nonlinear planar engagement kinematics and interceptor dynamics. The proposed system's performance is compared with a classical SMC based HG & Control system and with a conventional Augmented Proportional Navigation HG system that is made by replacing the outer guidance loop in the RGDI system for different interception scenarios. The simulations results reveal that the RGDI system supersedes its counterparts in accomplishing direct collision and hit-to-kill HG interception requirements, demonstrating its high-level performance abilities and robustness attributes against agile target maneuvers in the presence of uncertainties, disturbances, and measurement noises.

Robust Adaptive Sliding Mode Control Design for Quadrotor Unmanned Aerial Vehicle Trajectory Tracking

The quadrotor unmanned aerial vehicles (UAV) systems have been getting more focus recently from researchers and engineers due to their outstanding impact and wide range of applications either in civilian or military. In this article, the sliding mode controller has been designed to control the attitude of the quadrotor as the inner loop controller. The major aim in this research is to reduce the chattering associated with the conventional sliding mode control (SMC), by implementing the adaptive fuzzy gain scheduling SMC technique (AFGS-SMC). Meanwhile, the performance of the proposed control has been evaluated in the presence of the model parameters uncertainty. The PD controller has been implemented as an outer loop controller to control the quadrotor position and supply the inner loop proposed controller (AFGS-SMC) with the desired generated quadrotor's attitude. Finally, the performance of the proposed AFGS-SMC controller has been evaluated by simulation in Matlab/Simulink platform, and compared with the classical SMC, in terms of chattering attenuation and robust trajectory tracking in the presence of the parameter uncertainty in the mass of the quadrotor UAV.

DC-DC buck converter with second order sliding mode control: analysis design and implementation

This article presents design, analysis and implementation of second order sliding mode controller (SOSMC) for DC-DC buck converter. Firstly, second order sliding mode controllers with prescribed convergence law is designed using the buck converter model. The necessary bounds on the parameter variations for designing the SOSM are obtained. The closed loop stability condition is also derived using Lyapunov function. The SOSM controller is implemented with digital signal controller STM32F407VG based on ARM cortex M4 controller. The converter performance is assessed in simulation as well experimentally with the SOSMC and compared with classical sliding mode control. The effects of varying controller parameters and load disturbances are also analysed to endow the robust performance of the converter and efficacy of the algorithm.

Position controller design and implementation of ball and beam system with SMC and PD control methods

Today, several methods are proposed and tested for controlling many nonlinear and unstable systems. This study employed the sliding mode control (SMC) and proportional-derivative (PD), which are used to control the position and modeling of ball and beam system that is a fundamental system used to test the control methods. Such systems are nonlinear and unstable due to their nature. Therefore, these systems are affected by external disturbances and this leads to a decrease in the control quality. The study tested the system by utilizing the classical PD and SMC methods, and the results were assessed by employing the Integral-Square-Error (ISE) performance criterion. The system results were provided as graphics and tables. Besides, the results were compared and analyzed.

Closed Loop Control of Photo Voltaic Emulator Using Fractional Calculus

Threatening environmental effects have forced the community to utilize green and clean alternative options for the generation of electric power. As a matter of fact, solar energy is a critical source of energy; so the demand for creative research is its peak. However, performing real time experiments on solar PV systems is limited by cost, manufacturing, weather constraints and requirement of large space. Thus an equivalent solar energy photo voltaic (PV) system is required for experimental verification and analysis based on precise simulations. In this research work a PV emulator system based on a buck converter is realized. The main objective of PV Emulator is to replicate the characteristic curves (I-V, P-V) of the real solar panel. In order to compensate the variations in both the load and the parameters of power stage, a robust control system is required. A fractional order sliding mode control scheme (FOSMC) has been designed and investigated in this research work. Results have proved the superior performance of the FOSMC as compared to other classical sliding mode control method. The FOSMC controller and PV emulator are implemented using rapid prototyping technique.

Rotor vibration control of hybrid pole bearingless switched reluctance motor with C-dump converter

Rotor vibration control during start up, acceleration and deceleration phases is one of the key problems besides stable levitation, in high-speed applications of bearingless switched reluctance motor (BSRM). In this paper, an effective intelligent sliding mode controller is proposed for suppressing the rotor vibration due to residual unbalance and external disturbance during levitation and motoring phases. The parameters of time-varying sliding surface for avoiding high control gains and chattering are adjusted integrating the sliding mode control (SMC) and features of fuzzy logic control. The experimental studies conducted on a prototype BSRM system confirm that the application of fuzzy SMC guarantees the robust performance with less chattering under model uncertainties and unknown external disturbances compared to classical sliding mode controller.

A Modified SDRE-based Sub-optimal Hypersurface Design in SMC

Sliding Mode Control (SMC) plays a prominent role in dealing with matched uncertainties. In classical SMC design, the sliding surface (SS) is crucial to the guarantee for the stability and desired performance, especially if the system is nonlinear. A possible way to fulfill these desired performances for nonlinear systems is to use State Dependent Riccati Equation (SDRE) method, enabling SS to be designed even optimally. However, SDRE may suffer an inherent stability problem as well as a computational burden. To overcome these issues, in a recent study, a new SDRE method has been proposed. Therefore, this study takes advantages of the advanced SDRE method in designing a sub-optimal SS and also provides some comparative results with the conventional one to establish the feasibility of the proposed SDRE-based SMC control architecture experimentally. Experiments are conducted by using a 3-DOF helicopter platform and the results reveal that the proposed SDRE-based SMC is able to produce smoother SS than the conventional counterpart.