Fuzzy integral sliding mode controller design for boost converters

We consider the problem of designing an integral sliding mode controller for a nonlinear boost DC–DC converter based on the Takagi–Sugeno (T–S) fuzzy approach. We give an accurate T-S fuzzy model of a boost converter. We derive an existence condition of a sliding surface in terms of linear matrix inequalities (LMIs). We give a parameterization of the sliding surface using the solution matrices of the LMI existence condition. We also give a switching feedback control strategy to guarantee the reachability condition. We show that the proposed method can robustly regulate the output voltage under bounded model uncertainties. Finally, we give some simulation and experimental results to show the practicality and feasibility of the proposed method.     

Composite chattering-free discrete-time sliding mode controller design for active front steering system of electric vehicles

Nonlinear Dynamics - In order to reduce the adverse effects of internal uncertainty and external disturbance in the active front steering (AFS) system of electric vehicles, two chattering-free...     

Approximate continuous fixed-time terminal sliding mode control with prescribed performance for uncertain robotic manipulators

This paper studies an approximate continuous fixed-time terminal sliding mode control (CFTSMC) with prescribed performance for uncertain robotic manipulators. A transformation concerning tracking error using a fixed-time prescribed performance function is proposed to guarantee the transient and steady-state performance of trajectory tracking control for uncertain robotic manipulators within fixed time. Utilizing the transformed error, a smooth fixed-time sliding mode surface is designed. Then, based on the proposed sliding mode surface, an approximate CFTSMC scheme is presented to achieve inherent chattering-free control for uncertain robotic manipulators. According to the Lyapunov stability theory, it is proved that the position tracking error can be bounded in the prescribed performance boundaries and globally converges to a defined small region within fixed time and then approaches exponentially to the origin. Several numerical simulation results demonstrate the effectiveness and superiority of the proposed control strategy for uncertain robotic manipulators.

     

Finite time integral sliding mode control of hypersonic vehicles

This study investigates the tracking control problem for the longitudinal model of an airbreathing hypersonic vehicle (AHV) with external disturbances. By introducing finite time integral sliding mode manifolds, a novel finite time control method is designed for the longitudinal model of an AHV. This control method makes the velocity and altitude track the reference signals in finite time. Meanwhile, considering the large chattering phenomenon caused by high switching gains, an improved sliding mode control method based on nonlinear disturbance observer is proposed to reduce chattering. Through disturbance estimation for feedforward compensation, the improved sliding mode controller may take a smaller value for the switching gain without sacrificing disturbance rejection performance. Simulation results are provided to confirm the effectiveness of the proposed approach.     

Discrete-time integral terminal sliding mode-based speed tracking control for a robotic fish

Nonlinear Dynamics - This paper proposed a discrete-time integral terminal sliding mode (DITSM)-based forward speed tracking control for a robotic fish (RF). Due to the difficulty of quantification...     

Fractional order fixed-time nonsingular terminal sliding mode synchronization and control of fractional order chaotic systems

This paper presents fractional order fixed-time nonsingular terminal sliding mode control for stabilization and synchronization of fractional order chaotic systems with uncertainties and disturbances. First, a novel fractional order terminal sliding mode surface is proposed to guarantee the fixed-time convergence of system states along the sliding surface. Second, a nonsingular terminal sliding mode controller is designed to force the system states to reach the sliding surface within fixed-time and remain on it forever. Furthermore, the fractional Lyapunov stability theory is used to prove the fixed-time stability and the robustness of the proposed control scheme and estimate the upper bound of convergence time. Next, the proposed control scheme is applied to the synchronization of two nonidentical fractional order Liu chaotic systems and chaos suppression of fractional order power system. Simulation results verify the effectiveness of the proposed control scheme. Finally, some application issues about the proposed scheme are discussed.

     

A novel terminal sliding mode controller for a class of non-autonomous fractional-order systems

This paper introduces a finite-time control technique for control of a class of non-autonomous fractional-order nonlinear systems in the presence of system uncertainties and external noises. It is known that finite-time control methods demonstrate better robustness and disturbance rejection properties. Moreover, finite time control methods have optimal settling time. In order to design a robust finite-time controller, a new nonsingular terminal sliding manifold is proposed. The proposed sliding mode dynamics has the property of fast convergence to zero. Afterwards, a novel fractional sliding mode control law is introduced to guarantee the occurrence of the sliding motion in finite time. The convergence times of both reaching and sliding phases are estimated. The main characteristics of the proposed fractional sliding mode technique are (1) finite-time convergence to the origin; (2) the use of only one control input; (3) robustness against system uncertainties and external noises; and (4) the ability of control of non-autonomous fractional-order systems. At the end of this paper, some computer simulations are included to highlight the applicability and efficacy of the proposed fractional control method.     

Outer synchronization of small-world networks by a second-order sliding mode controller

The current work presents an experimentally validated analytical model for low-velocity impact between a sphere and a plate. The model accounts for plastic deformation as well as flexural vibrations. The elastic phases are modeled with a nonlinear Hertzian contact model, and the plastic phase is linearized with a non-homogeneous expression. The results are compared against newly carried out experiments. The model well captures the effect of plate thickness-to-sphere diameter ratio, impact velocity, and material properties. The model’s generalized framework allows consideration for various expressions of contact parameters, critical velocity, and residual indentation. Moreover, the proposed methodology can be easily incorporated into particle-based or discrete element modeling approaches for granular flows to evaluate the real-time coefficient of restitution as opposed to assuming the constant value beforehand. Simplified relations are provided to assist in evaluating the coefficient of restitution.     

An adaptive fuzzy sliding mode controller for MEMS triaxial gyroscope with angular velocity estimation

In this paper, an adaptive fuzzy sliding mode control (AFSMC) for Micro-Electro-Mechanical Systems (MEMS) triaxial gyroscope is proposed. First, a novel adaptive identification approach with sliding mode controller which can identify angular velocity and other system parameters is developed. And in order to reduce the chattering, an AFSMC is designed to approximate the upper bound of the uncertainties and external disturbances. Based on Lyapunov methods, these adaptive laws can guarantee that the system is asymptotically stable. Numerical simulations are investigated to verify the effectiveness of the proposed AFSMC scheme.     

Output-based discrete-time sliding mode control for a piezoelectrically actuated system

This paper presents a new scheme of discrete-time sliding mode control (DSMC) dedicated to precision positioning control of a piezoelectrically actuated system. Traditionally, a hysteresis model is required to compensate for the piezoelectric nonlinearity and a state observer is needed to implement the DSMC, which renders a time-consuming procedure. The proposed output-based DSMC scheme allows the relief of these computational burdens. Specifically, the piezoelectric nonlinearity is considered as a lumped perturbation term which is predicted by a perturbation estimation technique. The elimination of state observer is realized by establishing a control scheme based on the system output only. In addition, the stability of the control system is proved in theory. The effectiveness of the reported scheme is validated on a prototype piezoelectric actuation system by carrying out several experimental investigations.     

Adaptive integral sliding mode control with payload sway reduction for 4-DOF tower crane systems

Nonlinear Dynamics - An adaptive integral sliding mode control (AISMC) method with payload sway reduction is presented for 4-DOF tower cranes in this paper. The designed controller consists of...     

Robust control of reaction wheel bicycle robot via adaptive integral terminal sliding mode

Nonlinear Dynamics - In this paper, the modelling of a reaction wheel bicycle robot (RWBR) is identified from a second-order mathematical model which is similar to an inverted pendulum, and an...     

基于MATAB/Simulink的双电机速度跟踪伺服系统仿真

在分析直流无刷电机的数学模型的基础上,通过研究双电机速度跟踪伺服系统的结构与运行原理,对系统建立有效的仿真模型,完成了系统的计算机仿真.在MATLAB/Simulink环境下,采用基于位置的电控式跟踪控制策略,构建了双电机速度跟踪伺服系统仿真模型,主电机采用速度、电流双闭环控制,从电机在双闭环基础上外加位置环完成速度跟踪,并选择数字PID控制算法对系统进行仿真实验.仿真试验结果与系统设计要求一致,验证了数学模型的有效性及控制系统的合理性,有利于加快实际系统设计和调试的进程.     

控制力矩陀螺框架伺服系统的超低速测速方法

在超低转速下,有限的转速测量分辨率是影响控制力矩陀螺框架伺服系统控制性能的一个重要因素.在分析转速分辨率对超低速控制性能影响的基础上,提出了一种基于多周期后向差分的转速计算方法,可提高测速分辨率并保证测速带宽.针对后向差分带来的相位延迟会限制测速分辨率进一步提高的问题,在选取合适的差分周期基础上,采用Kalman预估器对框架转速进行预估,进一步提高了框架转速的测速分辨率及测速带宽.通过仿真表明,所提出的测速方法将转速分辨率提高了两个数量级,解决了框架伺服系统在超低转速下由于有限的转速测量分辨率造成的爬行现象.