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A multi‐motor coordinated tracking control strategy based on a disturbance sliding‐mode observer and an anti‐saturation non‐singular fast‐terminal sliding mode is proposed to address the issues of slow convergence and controller output saturation in multi‐motor coordinated control systems. Firstly, a mathematical model of a multi‐motor traction system considering uncertain parameter perturbations, external disturbances, and dead zones was established. Secondly, a disturbance sliding‐mode observer was designed based on the mathematical model to eliminate motor disturbances and estimate the torque. The observer's forward compensation was added to design a total‐consensus‐based fast non‐singular terminal sliding‐mode controller. Then, a fast anti‐saturation auxiliary system with fast finite‐time convergence was constructed. Finally, a comparative experiment was conducted with traditional anti‐saturation sliding‐mode control to demonstrate that the proposed method had faster convergence, stronger disturbance rejection, and better tracking performance in the presence of multi‐motor parameter perturbations, unknown disturbances, and input saturation.

The doubly fed induction generator (DFIG)-based wind energy conversion systems (WECSs) are prone to certain uncertainties, nonlinearities, and external disturbances. The maximum power transfer from WECS to the utility grid system requires a high-performance control system in the presence of such nonlinearities and disturbances. This paper presents a nonlinear robust chattering free super twisting fractional order terminal sliding mode control (ST-FOTSMC) strategy for both the grid side and rotor side converters of 2 MW DFIG-WECS. The Lyapunov stability theory was used to ensure the stability of the proposed closed-loop control system. The performance of the proposed control paradigm is validated using extensive numerical simulations carried out in MATLAB/Simulink environment. A detailed comparative analysis of the proposed strategy is presented with the benchmark sliding mode control (SMC) and fractional order terminal sliding mode control (FOTSMC) strategies. The proposed control scheme was found to exhibit superior performance to both the stated strategies under normal mode of operation as well as under lumped parametric uncertainties.

The dead-zone nonlinearity and uncertain dynamics inevitably weaken the tracking performance of the displacement system for a hydraulic roofbolter. To solve the above problem, a global sliding-mode controller based on a reduced-order proportional-derivative-type (PD-type) extended state observer (GSMC-PDESO) is proposed. Firstly, the displacement system model of a hydraulic roofbolter is built by using a compensation technique to suppress the effect of dead-zone nonlinearity on control performance. Following that, a novel extended state observer that has less dimensions and few gains than standard one, called reduced-order PD-type extended state observer, is designed, with the purpose of improving the estimation performance and suppressing noise amplification. Moreover, a global sliding-mode unit mainly composed of a novel global integral sliding-mode surface and a novel global sliding-mode control law is developed, which aims to improve global robustness, eliminate the chattering and adverse impact on estimation error of disturbances, as well as provide an effective and continuous control law. By comparing the proposed GSMC-PDESO with ten control methods, the comparative experimental results verify the effectiveness of the proposed GSMC-PDESO and strategies.

High‐order sliding mode control laws with gain adaptation algorithms are applied, in Region III, on a floating offshore wind turbine equipped by permanent magnet synchronous generator (PMSG). These adaptive control methods are especially efficient for systems with uncertainties and external perturbations and are well adapted to wind turbines systems. Such controllers can be implemented with very reduced knowledge of system model (only the relative degree is necessary) and strongly reduce the controller gains tuning effort. Simulations are made on Fatigue, Aerodynamics, Structures and Turbulence (FAST) software and compared with standard gain‐scheduled proportional–integral (PI) controllers.

Wheeled mobile robots (WMRs) have become increasingly vital role in modern industries. This research proposes a novel finite‐time prescribed performance sliding mode control (SMC) algorithm for the trajectory tracking of WMRs under effects of wheel slipping, wheel skidding, and external disturbances. The proposed approach consists of two key components. First, a novel sliding surface is proposed based on a prescribed performance function (PPF) and a non‐singular fast terminal sliding function (NFTSF), referred to as PP‐NFTSF. The proposed PP‐NFTSF ensures that tracking errors converge to zero in finite time, while the PPF and a transformed error function ensure stability throughout the robot's operation by maintaining error states within predefined bounds. This framework ensures boundaries around zero, thus guaranteeing that the position tracking error will be zero when the transformed error reaches zero. Second, a novel finite‐time non‐singular fast terminal SMC (NFTSMC) law with prescribed performance tracking errors, referred to as FPP‐NFTSMC, is proposed. This control law incorporates a second‐order algorithm to generate a continuous control signal, effectively minimizing the chattering phenomenon of SMC. Overall, the proposed control method maintains all the advantages of PPF, NFTSMC, and the second‐order algorithm, achieving high position tracking performance, decreasing the chattering phenomenon, obtaining finite‐time convergence, guaranteeing tracking error within the boundary of the PPF, and robustness. To illustrate the stability and finite‐time convergence of the WMR systems, a proof using the Lyapunov stability theory is performed. The effectiveness of the proposed control method is validated using two working scenarios: tracking straight and U‐shaped trajectories for a 4‐WMR. This paper combines a prescribed performance function with a non‐singular fast terminal sliding mode control technique to improve wheeled mobile robots' control performance under wheel slipping, wheel skidding, and external disturbances. A novel prescribed performance non‐singular fast terminal sliding function and a novel finite‐time prescribed performance non‐singular fast terminal sliding mode control are proposed, which help increase tracking performance and reduce the chattering effect. The effectiveness of the proposed control method is validated via simulation for a four‐wheeled mobile robot.

This paper presents novel chattering-free robust control strategies for addressing disturbances and uncertainties in a two-degree-of-freedom (2-DOF) unmanned aerial vehicle (UAV) dynamic model, with a focus on the highly nonlinear and strongly coupled nature of the system. The novelty lies in the development of sliding mode control (SMC), integral sliding mode control (ISMC), and terminal sliding mode control (TSMC) laws specifically tailored for the twin-rotor MIMO system (TRMS). These strategies are validated through both simulation and real-time experiments. A key contribution is the introduction of a uniform robust exact differentiator (URED) to recover rotor speed and missing derivatives, combined with a nonlinear state feedback observer to improve system observability. A feedback linearization approach, using lie derivatives and diffeomorphism principles, is employed to decouple the system into horizontal and vertical subsystems. Comparative analysis of the transient performance of the proposed controllers, with respect to metrics such as settling time, overshoot, rise time, and steady-state errors, is provided. The ISMC method, in particular, effectively mitigates the chattering issue prevalent in traditional SMC, improving both system performance and actuator longevity. Experimental results on the TRMS demonstrate the superior tracking performance and robustness of the proposed control laws in the presence of nonlinearities, uncertainties, and external disturbances. This research contributes a comprehensive control design framework with proven real-time implementation, offering significant advancements over existing methodologies.

In this study, a high robust control—second‐order sliding‐mode control (SOSMC) scheme is proposed to improve the DC‐link voltage dynamic performance of the grid‐side converter (GSC) for the doubly‐fed induction generator (DFIG) system under the wind turbine power disturbance and DC‐link capacitance parameter disturbance. In general, the wind speed is change with the environment and further has an effect on the power generation of the DFIG system. Besides, the capacitance of DC‐link capacitor may change with the working condition. To address this issue, a SOSMC scheme is proposed to replace the conventional proportional integral (PI) control for the DC‐link voltage controller of the GSC for the DFIG system in this study. By using the non‐linear SOSMC controller, the DFIG system is robust to the disturbance of the wind speed and the parameter of DC‐link capacitance. Compared with the conventional PI control scheme, the DFIG system with the proposed SOSMC scheme is much more robust, which has been verified in the MATLAB/Simulink platform.

Owing to the competitive advantages of fast response speed, large pushing force, high reliability, and high precision, the permanent magnet linear synchronous motor (PMLSM) has played an increasingly vital role in various high-speed and high-precision control systems. However, PMLSM exhibits nonlinear behavior in actual operation, and position tracking precision is negatively affected by friction, load changes, and other external disturbances. To meet the growing demand and solve the position tracking control problem for the PMLSM, the control system is critical. Sliding-mode control (SMC) has been used extensively in nonlinear control systems due to its superior performance characterized by simplicity, good dynamic response and insensitivity to parameter perturbation and external disturbances, and has been implemented in PMLSMs to track practical position. The objective of this article is to classify, scrutinize and review the major sliding-mode control approaches for position control of PMLSM. The three different conventional SMC methods, namely the boundary layer approach, the reaching law approach and the disturbance observer-based SMC, are discussed in detail. The four advanced forms of SMC, namely terminal SMC, super-twisting SMC, adaptive SMC and intelligent SMC, are also presented. A comparison of these approaches is given, in which the advantages and disadvantages of each approach are presented; additionally, they are presented in table form in order to facilitate reading. It is anticipated that this work will serve as a reference and provide important insight into position control of PMLSM systems.

Maintaining precise and robust control in robotic systems, particularly those with nonlinear dynamics and external disturbances, is a significant challenge in robotics. Sliding-mode control (SMC) is a widely used technique to tackle these issues; however, it is plagued by chattering and computational complexity, which limit its effectiveness in high-precision environments. This study aims to develop and assess a quantum-inspired sliding-mode control (QSMC) strategy to enhance the SMC’s robustness, precision, and computational efficiency, specifically in controlling a six-jointed articulated robotic arm. The methodology involves creating a comprehensive kinematic and dynamic model of the robot, followed by implementing both classic SMC and the proposed Q-SMC in a comparative way. The simulation results confirm that the Q-SMC method outperforms the classic SMC, particularly in reducing chattering, improving tracking accuracy, and decreasing energy consumption by approximately 3.79%. These findings suggest that the Q-SMC technique provides a promising alternative to classical control methods, with potential applications in tasks requiring high precision and efficient robotic manipulations.

This article compares first-order sliding mode control (FOSMC) with second-order sliding mode control (SOSMC) for squirrel-cage induction motor using two-level inverter. Investigating the renowned robustness of sliding mode control in handling uncertainties and disturbances, the study focuses on precision, tracking speed, robustness, and chattering reduction. Each control approach employs two evaluation functions, saturation (Sat) and hyperbolic tangent (Th). Simulations in MATLAB/SIMULINK assess motor stability under several conditions and disturbances, applying the Lyapunov criterion. The results highlight sliding mode control's superior robustness, especially with the hyperbolic tangent function in FOSMC while significantly reducing response time. Furthermore, SOSMC demonstrates improved tracking accuracy and minimized chattering with only two control loops than FOSMC with four loops. Simulation results validate the proposed technique, showcasing remarkable dynamic performance. This study offers valuable insights into selecting and implementing sliding mode control for squirrel-cage induction motors.