Adaptive Sliding Mode Control Technique Research Articles

Event-Trigger-Based Adaptive Barrier Function Higher-Order Global Sliding Mode Control Technique for Quadrotor UAVs

Event-Trigger-Based Adaptive Barrier Function Higher-Order Global Sliding Mode Control Technique for Quadrotor UAVs

Stick–Slip Suppression in Drill String Systems Using a Novel Adaptive Sliding Mode Control Approach

A novel control technique is presented in this paper, which is based on a first-order adaptive sliding mode that ensures convergence in a finite time without any prior information on the upper limits of the parametric uncertainties and/or external disturbances. Based on an exponent reaching law, this controller uses two dynamically adaptive control gains. Once the sliding mode is reached, the dynamic gains decrease in order to loosen the system’s constraints, which guarantees minimal control effort. The proof of convergence was demonstrated according to Lyapunov’s criterion. The proposed algorithm was applied to a drill string system to evaluate its performance because such systems present variable operating conditions caused by, for example, the type of rock. The effectiveness of the proposed controller was evaluated by conducting a comparative study that involved comparing it against a commonly used sliding mode controller, as well as other recent adaptive sliding mode control techniques. The different mathematical performance measures included energy consumption. The proposed algorithm had the best performance measures with the lowest energy consumption and it was able to significantly improve the functioning of the drill string system. The results indicated that the proposed controller had 20% less chattering than the classic SM controller. Finally, the proposed controller was the most robust to uncertainties in system parameters and external disturbances, thus demonstrating the auto-adjustable features of the controller.

Adaptive sliding mode control for semi‐Markov jump uncertain discrete‐time singular systems

AbstractThis note is devoted to the analysis of adaptive sliding mode control of H/passivity of semi‐Markov jump discrete‐time uncertain singular systems. We consider the constraints of parameter uncertainties, unknown nonlinear functions, and external disturbances throughout the model. Firstly, a novel mode‐independent sliding mode surface is constructed, then the sliding mode dynamic equation under the equivalent controller is obtained. Secondly, by introducing virtual points, several sufficiency criteria are derived for the sliding mode dynamic ensuring H/passive performance and stochastic admissibility with linear matrix inequalities form. Thirdly, the state trajectory can be driven into a switching band containing the origin by adaptive sliding mode control techniques. Finally, the effectiveness of our findings is demonstrated by comparing existing strategies with three simulation examples.

Observer-based robust impact angle control three-dimensional guidance laws with autopilot lag

Considering an air-based missile intercepting maneuvering target with desired impact angles, robust guidance laws with autopilot lag in three-dimensional coupling space are presented in this paper. First, combining the fixed-time stability theory and adaptive sliding mode control technique, a novel dual-layer adaptive fixed-time sliding mode disturbance observer is proposed to estimate the unknown target maneuver. The proposed disturbance observer releases the requirement of information on either the target maneuver or its derivative. To achieve interception with the desired impact angles, a novel guidance law based on the nonsingular terminal sliding mode (NTSM) with an exponent coefficient is provided. The proposed control framework prevents singular problems and ensures the fixed-time stability of the guidance system. In addition, autopilot dynamics are taken into consideration, and the dynamics surface control (DSC) method is used to address the nonlinear static feedback system. Meanwhile, the improved fixed-time differentiator is used to acquire the derivative of virtual control laws. This prevents the inherent “differential explosion” of the backstepping technique. The uniform boundedness of the closed-loop system is demonstrated via the Lyapunov method. Finally, numerous numerical simulations are carried out, and the simulation results verify the effectiveness of the proposed guidance laws.

Unmanned mobile robot in unknown obstacle environments for multi switching control tracking using adaptive nonlinear sliding mode control method

This paper focuses on a wheeled mobile robot that utilizes the Adaptive Nonlinear Sliding mode control technique for trajectory tracking and obstacle avoidance control. A parallel wheeled differential drive Mobile robot’s trajectory tracking control problem is investigated. For diverse initial conditions, the robot must follow a given course to reach it’s destination. To monitor and identify the obstacles in the path, an obstacle micro-controller is fixed to decide quick crash avoidance and follow the obstacle limit at a predetermined distance. It depends on the robot’s vector connections. An Adaptive Nonlinear Sliding Mode (ANSM) control concept is used for continuous trajectory tracking or object monitoring in the path to avoid it. A Lapunov function control gives stability to each controller. The proposed simulation results demonstrate that the mobile robot can be applied to guarantee its protected development in an obscure obstacle environment. In detail, the proposed control gives another, more straightforward methodology with application esteems for tracking critical thinking in an obscure obstacle environment. Finally, based on these above characteristics, the proposed control strategy’s efficiency, simplicity, and accuracy prove. The steady-state error and mean squared error of the proposed ANSM are 6% and 0.07db, respectively.

An experimental study of adaptive bounded depth control for underwater vehicles subject to thruster’s dead-zone and saturation

Accurate depth tracking control is of great importance for an underwater vehicle that performs an underwater task such as seabed mapping and underwater docking. This paper addresses the problem of adaptive depth tracking control for an underwater vehicle, particularly in the presence of hydrodynamics uncertainty, thruster’s dead-zone and saturation. Before deriving an adaptive depth control law, an unified and continuous hydrodynamics model in heave is built, where the thruster’s characteristics composed of output time-delay, input dead-zone and saturation are taken into consideration. Subsequently, fuzzy universal approximation theorem is resorted to online approximate the unknown and complex hydrodynamics in heave, and then adaptive sliding mode control technique is utilized to compensate for the approximation residual. In order to reject inherent input saturation, gradient projection method is introduced into the above adaptive control law, resulting in an adaptive bounded depth control law. Furthermore, through obtaining two dead-zone breakpoints in advance and online translation compensation, the final control output can always change within the permitted range. Finally, three comparative experiments are performed to verify the outperformance of the designed adaptive bounded depth tracking controller.

Adaptive Continuous Barrier Function Terminal Sliding Mode Control Technique for Disturbed Robotic Manipulator

This paper offers an improved finite time sliding mode controller scheme for a class of robotic manipulators with external disturbances. Since conventional sliding mode controllers have a discontinuous signum function, an important problem called chattering phenomenon can occur in them. The proposed scheme presents a new Lyapunov candidate functional containing an absolute function based on a fractional power of the switching surface such that the designed control law is continuous and smooth. The recommended control technique is designed using the Lyapunov stability theory and satisfies the presence of the sliding mode around designed switching surface in the finite time. The presented method eliminates the chattering problem produced by the switching controller and satisfies high precision action. Besides, the adaptive tuning controllers are designed to approximate the unknown bound of external disturbance. An extension of the proposed control technique based on the barrier function adaptive terminal sliding mode control is also suggested for better performance and robust tracking control of the nonlinear systems with external disturbances. Some simulation and experimental outcomes exhibit the efficacy of the planned technique.

Coupled Dynamic Modeling and Control of Aerial Continuum Manipulation Systems

Aerial continuum manipulation systems (ACMSs) were newly introduced by integrating a continuum robot (CR) into an aerial vehicle to address a few issues of conventional aerial manipulation systems such as safety, dexterity, flexibility and compatibility with objects. Despite the earlier work on decoupled dynamic modeling of ACMSs, their coupled dynamic modeling still remains intact. Nonlinearity and complexity of CR modeling make it difficult to design a coupled ACMS model suitable for practical applications. This paper presents a coupled dynamic modeling for ACMSs based on the Euler–Lagrange formulation to deal with CR and the aerial vehicle as a unified system. For this purpose, a general vertical take-off and landing vehicle equipped with a tendon-driven continuum arm is considered to increase the dexterity and compliance of interactions with the environment. The presented model is independent of the motor’s configuration and tilt angles and can be applied to model any under/fully actuated ACMS. The modeling approach is complemented with a Lyapunov-wise stable adaptive sliding mode control technique to demonstrate the validity of the proposed method for such a complex system. Simulation results in free flight motion scenarios are reported to verify the effectiveness of the proposed modeling and control techniques.

On The Anti-Synchronization Of Fractional-Order Chaotic And Hyperchaotic Systems Via Modified Adaptive Sliding-Mode Control

This paper investigates the anti–synchronization problem between two different fractional-order chaotic and hyperchaotic systems using the modified adaptive sliding mode control technique in the presence of uncertain system parameters. To construct the proposed scheme, a simple sliding surface is first designed. Then, the modified adaptive sliding-mode controller is derived to guarantee the occurrence of sliding motion. Based on the Lyapunov stability theory, the adaptive controllers with corresponding parameter update laws are designed such that the different chaotic and hyperchaotic systems can be anti–synchronized asymptotically. Finally, numerical simulations are presented to demonstrate the efficiency of the proposed anti–synchronization scheme.

Synchronization of different order fractional-order chaotic systems using modify adaptive sliding mode control

This paper proposes a modified adaptive sliding-mode control technique and investigates the reduced-order and increased-order synchronization between two different fractional-order chaotic systems using the master and slave system synchronization arrangement. The parameters of the master and slave systems are different and uncertain. These systems exhibit different chaotic behavior and topological properties. The dynamic behavior of the proposed synchronization schemes is more complex and unpredictable. These attributes of the proposed synchronization schemes enhance the security of the information signal in digital communication systems. The proposed switching law ensures the convergence of the error vectors to the switching surface and the feedback control signals guarantee the fast convergence of the error vectors to the origin. Lyapunov stability theory proves the asymptotic stability of the closed-loop. The paper also designs suitable parameters update laws the estimate the unknown parameters. Computer-based simulation results verify the theoretical findings.

Design of Sliding Mode Controlled Bi-directional DC-DC Current Source Resonant Converter for an Inductive Contactless Battery Charging Application

The practical use of current source DC-DC resonant converters has an outstanding performance in terms of its robust and fast performance. In this paper, the non-linear behavior during the battery charging application is solved using an adaptive Sliding Mode Control (SMC) technique. The SMC has a robust feature in fast transient responses over large load disturbances. The proposed converter uses Contactless Energy Transfer (CET) system that provides a suitable reactive power compensation for the design. The winding parameters of the inductance are mathematically modeled with low coupling factor to remove the voltage and current harmonics. The designed converter is subjected to input side perturbation for a non-linear disturbance and the output obtained using the Sliding Mode Controller is analysed. The non-linearity at the output voltage is reduced when using the SMC. The controller design show the setting time of the DC voltage under such disturbance is reduced to 97%. The proposed system is mathematically modeled and simulated using MATLAB/Simulink. The prototype model is designed and the results are analyzed.

Synchronization of Non-Integer Complex Chaotic Systems with Uncertainty and Disturbances via Adaptive Sliding Mode Technique

In this paper we concern the adaptive sliding mode control technique for synchronization of fractional order chaotic systems with uncertainties and disturbances. This technique is used to design control law through suitable sliding surface and estimate the external disturbances. Computational results using MATLAB verified the effectiveness of the proposed scheme.

Compound synchronization using disturbance observer based adaptive sliding mode control technique

This manuscript addresses a methodology for investigating compound synchronization in a class of commensurate FO chaotic Genesio-Tesi system using DOB adaptive sliding mode control technique among fractional order chaotic systems with unknown bounded disturbances. The unknown disturbances are estimated using the nonlinear fractional order disturbance observer. Sliding mode technique has been employed by considering a simple sliding surface among four identical fractional order chaotic systems to achieve the desired synchronization which is further based on Lyapunov stability theory. The obtained results have been compared with prior published literature to realize the robustness of the proposed strategy. Finally, some numerical results using MATLAB are illustrated for visualizing the effectiveness and the correctness of the developed approach on the considered system in the presence of external disturbances.

Compound synchronization using disturbance observer based adaptive sliding mode control technique

This manuscript addresses a methodology for investigating compound synchronization in a class of commensurate FO chaotic Genesio-Tesi system using DOB adaptive sliding mode control technique among fractional order chaotic systems with unknown bounded disturbances. The unknown disturbances are estimated using the nonlinear fractional order disturbance observer. Sliding mode technique has been employed by considering a simple sliding surface among four identical fractional order chaotic systems to achieve the desired synchronization which is further based on Lyapunov stability theory. The obtained results have been compared with prior published literature to realize the robustness of the proposed strategy. Finally, some numerical results using MATLAB are illustrated for visualizing the effectiveness and the correctness of the developed approach on the considered system in the presence of external disturbances.

Synchronization on the adaptive sliding mode controller for fractional order complex chaotic systems with uncertainty and disturbances

The present paper purports to examine and analyse the concept of non identical complex chaotic systems of fractional order with external bounded disturbances and uncertainties. Hybrid projective synchronization has been achieved between fractional order complex Lu-system (drive system) and complex T-system (slave system). The adaptive sliding mode control technique has been used to design control law through suitable sliding surface and estimate the uncertainties and external disturbances in order to establish the stability of controlled system by using allied theorems. Also we have compared our results with prior published literature results to determine the supremacy of considered methodology. Computer simulations outcomes have established the efficacy and adeptness of the prospective scheme.

Dynamical analysis, sliding mode synchronization of a fractional-order memristor Hopfield neural network with parameter uncertainties and its non-fractional-order FPGA implementation

Recent developments in the applications of neural networks in various engineering and technology applications have motivated researchers to study the nonlinear behavior of such networks. In this work we investigate a fractional-order Hopfield neural network with memristor synaptic weight. The dynamical properties of the proposed system are examined and the memristor neural network shows hyperchaotic attractors in fractional orders with hidden oscillations. We also propose an adaptive sliding mode control technique to synchronize the proposed fractional-order systems with uncertainties. Numerical simulations are derived to show the effectiveness of the synchronization algorithm. Moreover, the designed chaotic memristor Hopfield neural network system is realized on FPGA using the 4th-order Runge–Kutta (RK4) numerical algorithm. The FPGA-based chaotic memristor HNN is coded in VHDL using the 32-bit IEEE-754-1985 floating point standard. The chaotic memristor neural network designed on FPGA is synthesized and tested using Xilinx ISE. The chip statistics of Xilinx XC6VLX240T-1-FF1156 kit obtained from Place & Route operation for the designed RK4-based system is presented. The operating frequency of newly modeled FPGA-based memristor neural network chaotic signal generator is 231.616 MHz.

New design methodology for adaptive switching gain based discrete-time sliding mode control

The adaptive sliding mode control technique relaxes the assumption of known bound of the disturbance in discrete-time systems. However, the existing technique of gain adaptation in discrete-time sliding mode control has issues of gain overestimation and underestimation. Therefore, this paper proposes a technique to adapt the switching gain such that the adaptive gain can tackle the uncertainty without any knowledge of the bound of uncertainty while overcoming the over- and under-estimation problems of switching gain.

Robust adaptive sliding mode control technique for combination synchronisation of non-identical time delay chaotic systems

This manuscript presents the methodology in which robust adaptive sliding mode control technique is used for implementing combination synchronisation of non-identical time-delay chaotic systems. To justify this methodology, modified Lorenz chaotic time delay system and Genesio time delay system are used. The stability condition for the error dynamics is analysed using Lyapunov stability theory and detailed mathematical theory. Numerical simulations are carried out to demonstrate the efficiency of the proposed approach that supports the analytical results.

A Novel Nonlinear Fault Tolerant Control for Manipulator under Actuator Fault

A fault tolerant control (FTC) scheme based on adaptive sliding mode control technique is proposed for manipulator with actuator fault. Firstly, the dynamic model of manipulator is introduced and its actuator faulty model is established. Secondly, a fault tolerant controller is designed, in which both the parameters of actuator fault and external disturbance are estimated and updated by online adaptive technology. Finally, taking a two-joint manipulator as example, simulation results show that the proposed fault tolerant control scheme is effective in tolerating actuator fault; meanwhile it has strong robustness for external disturbance.

Saturated adaptive sliding mode control for autonomous vessel landing of a quadrotor

An autonomous vessel landing control algorithm of a quadrotor with input saturation and parametric uncertainties is investigated. To facilitate the controller design, the problem of vessel landing is converted from general trajectory tracking problem of a quadrotor to a stabilisation problem of relative motion. A non-linear and coupled six-degrees-of-freedom relative position and attitude model with uncertain parameters and external disturbances is established. The proposed controllers are composed of a relative position controller (RPC) and a relative attitude-altitude controller (RAC). The quadrotor is first commanded by RPC to reach above the vessel, as it reaches, RAC is initiated to guide the quadrotor to descend steadily on the vessel. Both RPC and RAC employ the saturated adaptive sliding mode control technique. The parametric uncertainties and disturbances are estimated by adaptive algorithms, while the control input saturation effect is compensated by linear compensators. All signals in the closed-loop systems are proved uniformly ultimately bounded via Lyapunov theory. Numerical simulations validate the effectiveness of the proposed control approach.