Adaptive super-twisting sliding mode control for a three-phase single-stage grid-connected differential boost inverter based photovoltaic system

This paper presents an adaptive super-twisting sliding mode control (STC) along with double-loop control for voltage tracking performance of three-phase differential boost inverter and DC-link capacitor voltage regulation in grid-connected PV system. The effectiveness of the proposed control strategies are demonstrated under realistic scenarios such as variations in solar insolation, load power demand, grid voltage, and transition from grid-connected to standalone mode etc. Additional supplementary power quality control functions such as harmonic compensation, and reactive power management are also investigated with the proposed control strategy. The results are compared with conventional proportional-integral controller, and PWM sliding mode controller. The system performance is evaluated in simulation and in real-time.     

四旋翼飞行器的自适应鲁棒滑模控制器设计

针对四旋翼欠驱动系统的姿态控制问题,提出一种自适应鲁棒滑模控制方法。对四旋翼系统实现了双环控制,内环为姿态控制,外环为位置控制。根据牛顿-欧拉方程建立了四旋翼系统的动力学模型,针对系统中的外部扰动和参数摄动等不确定性因素,设计了基于Lyapunov稳定控制算法,内环使用自适应鲁棒滑模控制;外环使用鲁棒控制。仿真和实验表明所提控制策略对外界扰动和模型的不确定性具有较强的鲁棒性。     

RTDS implementation of an improved sliding mode based inverter controller for PV system

This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier. The implementation of a control strategy with high bandwidth in small time steps of Real Time Digital Simulator (RTDS) is not straight forward. This paper shows a good methodology for the practitioners to implement such control scheme in RTDS. As a part of the industrial process, the controller parameters are optimized using particle swarm optimization (PSO) technique to improve the low voltage ride through (LVRT) performance under network disturbance. The response surface methodology (RSM) is well adapted to build analytical models for recovery time (R_t), maximum percentage overshoot (MPOS), settling time (T_s), and steady state error (E_ss) of the voltage profile immediate after inverter under disturbance. A systematic approach of controller parameter optimization is detailed. The transient performance of the PSO based optimization method applied to the proposed sliding mode controlled PV inverter is compared with the results from genetic algorithm (GA) based optimization technique. The reported real time implementation challenges and controller optimization procedure are applicable to other control applications in the field of renewable and distributed generation systems.     

Buck型变换器滑模控制技术及其发展综述

介绍了滑模控制技术的基本概念.以Buck型变换器为例,对包括变频滑模控制技术和定频滑模控制技术在内的滑模控制技术作了综合论述.运用相平面法形象地描述了滑模运动,并采用映射法把三维轨迹化为两维情况,简化了分析过程.最后预测了滑模控制技术的发展趋势及今后研究的重点问题.     

Discrete sliding mode controller with reaching phase elimination for TITO systems

Sliding mode control (SMC) is emerged as a powerful robust controller for the process control application. However, it does not posses robustness properties during reaching phase and suffers from chattering, which is undesirable. In this paper, a chatter free discrete sliding mode controller (DSMC) with reaching phase elimination is proposed. The issue of existence of reaching phase due to physical constraints such as saturation of actuating devices is also addressed. The two-input–two-output (TITO) system is decoupled into two single-input–single-output (SISO) systems using ideal decoupler. The DSMCs are separately designed for two decoupled SISO systems. The stability is ensured via Lyapunov approach. Simulation study and experimentation on real life interacting two tank liquid level system are included to demonstrate effectiveness and applicability of the proposed controller.     

Buck 变换器导通模式转换滑模 PI 混合控制策略

为了满足Buck变换器由待机或轻载向较大负载状态快速转换的需求,基于对传统平均电流控制Buck变换器的动态性能分析,提出了一种改进的适用于断续导通模式/连续导通模式过程的滑模PI混合控制策略。该策略电压外环依据系统状态和导通模式分别采用PI控制器和滑模控制器,其中稳态工况应用PI控制器,负载增大动态工况根据导通模式转换为滑模控制器,并通过统一校正的平均电感电流实现导通模式的准确判断。该混合控制策略可以有效结合PI控制与滑模控制各自的稳态与动态性能优势。仿真和实验结果表明,相比于传统平均电流控制,本策略动态响应时间缩短约65%,电压跌落减小35%以上。     

Smooth integral sliding mode controller for the position control of Stewart platform

This paper proposes the application of a new algorithm for the position control of a Stewart platform. The conventional integral sliding mode controller is a combination of nominal control and discontinuous feedback control hence the overall control is discontinuous in nature. The discontinuity in the feedback control is undesirable for practical applications due to chattering which causes the wear and tear of the mechanical actuators. In this paper the existing integral sliding mode control law for systems with matched disturbances is modified by replacing the discontinuous part by a continuous modified twisting control. This proposed controller is continuous in nature due to the combinations of two continuous controls. The desired position of the platform has been achieved using the proposed controller even in the presence of matched disturbances. The effectiveness of the proposed controller has been proved with the simulation results.     

Continuous high order sliding mode controller design for a flexible air-breathing hypersonic vehicle

This paper investigates the problem of tracking control with uncertainties for a flexible air-breathing hypersonic vehicle (FAHV). In order to overcome the analytical intractability of this model, an Input–Output linearization model is constructed for the purpose of feedback control design. Then, the continuous finite time convergence high order sliding mode controller is designed for the Input–Output linearization model without uncertainties. In addition, a nonlinear disturbance observer is applied to estimate the uncertainties in order to compensate the controller and disturbance suppression, where disturbance observer and controller synthesis design is obtained. Finally, the synthesis of controller and disturbance observer is used to achieve the tracking for the velocity and altitude of the FAHV and simulations are presented to illustrate the effectiveness of the control strategies.     

车联网环境下电子节气门全局快速滑模控制

车联网是目前汽车电子领域的研究热点,而车车通信是实现车联网的重要技术手段.为了提高车车通信过程中汽车电子节气门的控制性能,提出了基于Luenberger观测器的电子节气门全局快速滑模控制.具体来讲,首先,基于电子节气门的非线性模型,设计了Luenberger滑模观测器,以实现对节气门开度变化的在线估计;其次,以节气门开度误差为输入,通过李雅普诺夫稳定性理论设计了全局快速滑模控制器与外部扰动自适应律,以确保系统的稳定性和鲁棒性.最后,对提出的控制方法进行仿真验证,并与现有方法进行对比分析,仿真结果证明了所提出控制方法的有效性.     

Evolutionary optimization of sliding mode controller for level control system

This paper accords the level control of single-input-single-output (SISO) level control system based on the fusion of sliding mode control (SMC) and evolutionary techniques or bio-inspired techniques. The non-dominated sorting genetic algorithm II (NSGA-II) and multi-objective particle swarm optimization (MOPSO) are considered as two evolutionary techniques. Here, a comparative analysis of performances of an optimal proportional–integral (PI) controller, proportional–integral–derivative (PID) controller, conventional SMC, NSGA-II based tuned SMC and SMC parameter tuning using MOPSO algorithm has been carried out through MATLAB/SIMULINK. The objective functions, integral absolute error (IAE), integral squared error (ISE) and an integration of weighted objective function aggregated approach of the error performance indices, IAE and ISE are considered. Realistic conditions are used in a plant for testing the robustness of controller. The stability of the controller is successfully obtained which satisfies the Lyapunov stability criteria. Reduction in long settling time with tiny magnitude variations about an equilibrium point is achieved using bio-inspired techniques. The simulation as well as experimental results reveal that SMC parameter tuning based on NSGA-II algorithm gives a better performance as compared to the other design strategies.     

基于Terminal的船舶动力定位系统控制器设计

滑模变结构控制是一种特殊的非线性控制,它具有快速响应、实现简单、对扰动不灵敏、无需在线辨识等优点。船舶动力定位系统属于不确定、非线性的系统,本文对一船舶动力定位系统的数学模型进行了Terminal滑模控制器设计、通过Matlab中的Simulink进行仿真,仿真的结果验证了滑模变结构控制对船舶动力定位系统控制的有效性。     

Adaptive nonsingular terminal sliding mode controller for micro/nanopositioning systems driven by linear piezoelectric ceramic motors

In the field of nanotechnology, there is a growing demand to provide precision control and manipulation of devices with the ability to interact with complex and unstructured environments at micro/nano-scale. As a result, ultrahigh-precision positioning stages have been turned into a key requirement of nanotechnology. In this paper, linear piezoelectric ceramic motors (LPCMs) are adopted to drive micro/nanopositioning stages since they have the ability to achieve high precision in addition to being versatile to be implemented over a wide range of applications. In the establishment of a control scheme for such manipulation systems, the presence of friction, parameter uncertainties, and external disturbances prevent the systems from providing the desired positioning accuracy. The work in this paper focuses on the development of a control framework that addresses these issues as it uses the nonsingular terminal sliding mode technique for the precise position tracking problem of an LPCM-driven positioning stage with friction, uncertain parameters, and external disturbances. The developed control algorithm exhibits the following two attractive features. First, upper bounds of system uncertainties/perturbations are adaptively estimated in the proposed controller; thus, prior knowledge about uncertainty/disturbance bounds is not necessary. Second, the discontinuous signum function is transferred to the time derivative of the control input and the continuous control signal is obtained after integration; consequently, the chattering phenomenon, which presents a major handicap to the implementation of conventional sliding mode control in real applications, is alleviated without deteriorating the robustness of the system. The stability of the controlled system is analyzed, and the convergence of the position tracking error to zero is analytically proven. The proposed control strategy is experimentally validated and compared to the existing control approaches.     

弱电网下并网逆变器锁相环优化方法

针对弱电网条件下并网逆变器锁相环精度易受电网电压畸变、频率偏移、三相电压不平衡以及直流电压偏置等工况影响的问题,本文提出一种适用于弱电网下并网逆变器的解耦双同步坐标系锁相环(DDSRF-PLL)优化方法。首先在建立DDSRF-PLL模型的基础上,从理论角度证明电网电压畸变和直流电压偏置是影响传统DDSRF-PLL锁相精度的关键因素;而后利用傅里叶变换具备抗谐波和抗直流偏置干扰的优点,提出基于滑动傅里叶变换(SFT)的频率自适应鉴相器,继而构建适用于并网逆变器的优化解耦双同步坐标系锁相环。在电网电压发生畸变时本文所提锁相环在20 ms内可以完成对电压相位跟踪,在电网电压存在直流偏置的情况下本文所提锁相环能在10 ms内快速跟踪电压相位,且相位超调量在1°以内。实验结果表明,本文所提锁相环在弱电网环境下能快速准确的提取电网电压的频率和相位信息,有助于并网逆变器在电网电压畸变、电网电压直流偏置和电网电压不平衡等复杂工况下降低输出电流谐波含量。     

Design and implementation of continuous finite-time sliding mode control for 2-DOF inertially stabilized platform subject to multiple disturbances

Control performances of inertially stabilized platforms (ISPs) are always affected by various disturbed phenomena such as cross-couplings, mass unbalance, parameter variations, and external disturbances in real applications. To improve the dynamic response and the disturbance rejection ability of the ISP, a continuous finite-time sliding mode control (SMC) approach with cascaded control structure is proposed. By constructing a finite-time disturbance observer, the multiple disturbances are precisely estimated in real time without the complex modeling and calibration work. Under the field oriented control framework, for the stabilized loop subsystem, an improved super-twisting controller incorporating the disturbance estimates is developed whereas for the current loop subsystem, the super-twisting control method is directly employed. Finite-time convergence of the inertial angular rates is guaranteed with the continuous control action such that chattering is alleviated remarkably. Moreover, by utilizing the manner of disturbance compensation, the feedback control gains can be tuning down without sacrificing the disturbance rejection ability. Comparative experiments are performed to verify the effectiveness of the proposed control approach.     

Design of an adaptive super-twisting decoupled terminal sliding mode control scheme for a class of fourth-order systems

This paper proposes an adaptive super-twisting decoupled terminal sliding mode control technique for a class of fourth-order systems. The adaptive-tuning law eliminates the requirement of the knowledge about the upper bounds of external perturbations. Using the proposed control procedure, the state variables of cart-pole system are converged to decoupled terminal sliding surfaces and their equilibrium points in the finite time. Moreover, via the super-twisting algorithm, the chattering phenomenon is avoided without affecting the control performance. The numerical results demonstrate the high stabilization accuracy and lower performance indices values of the suggested method over the other ones. The simulation results on the cart-pole system as well as experimental validations demonstrate that the proposed control technique exhibits a reasonable performance in comparison with the other methods.     

树障清理空中机器人的姿态控制器设计

以一种用于对高压线路附近的树障进行清理的树障清理空中机器人为研究对象,分析其姿态控制问题。首先,建立了具有新型结构的树障清理空中机器人的姿态动力学模型和控制分配矩阵。然后,为了克服惯性矩阵的不确定性,采用滑模方法设计姿态控制器;同时,引入非线性函数来改进传统的边界层法以提高控制器性能;接着提出了一种切换控制分配矩阵的方法来解决空中机器人在切割作业过程中的动力学模型变化的问题。最后,在仿真平台上实现了上述控制器。实验结果表明,本滑模控制器具有良好的姿态控制性能,能有效克服机体惯量的不确定性;通过切换控制分配矩阵实现了空中机器人在切割作业过程中的姿态稳定。     

一类多缸液压机的分散滑模控制

通过对一类锻造液压机的分析,在考虑多缸耦合情况下为其建立了非线性系统数学模型.将该模型视为非线性关联大系统,且将其转化为可控正则型,提出采用分散滑模控制理论对其进行滑模变结构控制.针对模型转换后控制方程中状态量与控制量同时具有关联性的特点,提出通过模拟求解一个多元一次方程组的方法,得到了基于指数趋近律的分散滑模控制律,有效解决了多缸耦合情况下控制律难于求解的问题.仿真结果表明,所设计的控制器使系统实现了高精度的位置跟踪,获得了较强的抗扰性,控制效果良好,且所提方法思路清晰,为同类模型的控制方案提供了参考.     

Synchronization of chaotic systems with known and unknown parameters using a modified active sliding mode control

This paper defines a new surface in an active sliding mode to synchronize two chaotic systems with parametric uncertainty. To verify the capability of the proposed scheme, signals are also contaminated by measurement noise. The integral acting surface produces a dynamics for error, where the appropriate eigenvalues are easily assigned. Using this surface, calculation of parameters of the controller becomes simpler than the classical alternative. A sufficient condition, as a guideline of the designated procedure, is dedicated to provide a robust stability of the error dynamics. Finally, a simulation study is performed to verify the robustness and effectiveness of the proposed control strategy.     

A new fractional-order sliding mode controller via a nonlinear disturbance observer for a class of dynamical systems with mismatched disturbances

This paper investigates the stabilization and disturbance rejection for a class of fractional-order nonlinear dynamical systems with mismatched disturbances. To fulfill this purpose a new fractional-order sliding mode control (FOSMC) based on a nonlinear disturbance observer is proposed. In order to design the suitable fractional-order sliding mode controller, a proper switching surface is introduced. Afterward, by using the sliding mode theory and Lyapunov stability theory, a robust fractional-order control law via a nonlinear disturbance observer is proposed to assure the existence of the sliding motion in finite time. The proposed fractional-order sliding mode controller exposes better control performance, ensures fast and robust stability of the closed-loop system, eliminates the disturbances and diminishes the chattering problem. Finally, the effectiveness of the proposed fractional-order controller is depicted via numerical simulation results of practical example and is compared with some other controllers.