基于类二次型Lyapunov函数的Super-twisting算法收敛性分析

基于非光滑的类二次型Lyapunov函数，对二阶滑模Supevtwisfing算法的有限时间收敛性进行了分析．当系统受常值干扰时，通过Lyapunov方程证明了该算法有限时间收敛，并给出了收敛时间的最优估计；当系统受时变干扰时，通过求解代数Riccati方程得出了一组保证该算法有限时间收敛的参数取值范围，并给出了收敛时间的估计值．仿真算例表明了理论分析的正确性．  

基于双观测器并行结构的四旋翼无人机故障检测与重构

以四旋翼飞行器执行单元增益型故障的检测与重构为研究内容，设计基于滑模观测器的故障检测算法。针对飞行器姿态控制系统的驱动单元冗余特性，提出一种并行双降维观测器与超螺旋算法相结合的故障重构算法。对所提出的算法进行了理论分析，并通过数值仿真验证了所提出算法的有效性。  

基于二阶滑模的汽油机瞬态空燃比控制

为克服瞬态工况下油膜动态特性对空燃比控制精度的影响,提出了一种二阶滑模空燃比控制策略。通过对发动机平均值模型的分析,确定其作为单输入单输出(SISO)系统的非线性形式,设计了基于Super-twisting算法的二阶滑模空燃比控制器并运用Matlab建模仿真。仿真结果表明,基于Super-twisting算法的二阶滑模控制器鲁棒性强;与PID控制器和一阶滑膜控制器相比较,控制精度和速度明显提高。  

Second-order Sliding Mode Approaches for the Control of a Class of Underactuated Systems

In this paper, first-order and second-order sliding mode controllers for underactuated manipulators are proposed. Sliding mode control(SMC) is considered as an effective tool in different studies for control systems. However, the associated chattering phenomenon degrades the system performance. To overcome this phenomenon and track a desired trajectory, a twisting, a supertwisting and a modified super-twisting algorithms are presented respectively. The stability analysis is performed using a Lyapunov function for the proposed controllers. Further, the four different controllers are compared with each other. As an illustration, an example of an inverted pendulum is considered. Simulation results are given to demonstrate the effectiveness of the proposed approaches.  

基于二阶滑模观测器的连续系统故障估计

针对传统的滑模观测器在实现故障估计时带来的抖振问题，设计基于super-twisting算法的二阶滑模观测器以稳定地估计出故障。针对以往利用几何或齐次性方法证明super-twisting算法稳定性过程繁琐的缺点，采用Lyapunov函数来证明稳定性。给出的故障估计结果克服了传统的滑模观测器在估计故障时带来的时延或引进新参数等缺点。最后，将所提出的方法应用于某型飞控系统，结果表明了所提出方法的有效性。  

不确定欠驱动系统的高阶自适应Super-Twisting滑模控制

为实现一类不确定欠驱动系统在未知干扰情况下的鲁棒控制,针对传统滑模控制中存在的抖振问题,提出一种基于二次型Lyapunov函数的二阶Super-Twisting自适应滑模控制策略.首先,控制器的不连续项采用二阶Super-Twisting算法,将不连续控制作用在滑模量的二阶导数.然后,针对滑模面受不确定干扰影响的情况,为调节参数设计一种自适应律方法,该方法不受传统二阶滑模控制中干扰项的一阶导数边界已知的条件限制,保证滑模面在有干扰情况下的收敛,削弱控制器输入的抖振现象.最后,以两轮自平衡车为实验对象验证该方法,并与传统滑模及普通二阶滑模方法做仿真对比.仿真结果表明文中所提的二阶自适应滑模控制方法在控制效果和降低抖振方面表现更优.  

二阶滑模控制在远程网络控制时滞系统中的应用

针对直流无刷电机的远程网络控制系统中的控制时滞和参数不确定的问题,采用线性非奇异变换将控制存在时滞的线性系统转化为无时滞系统;借助于二次型时间最优的方法,利用二阶超螺旋算法,设计出简单、易于实现的二阶滑模控制器。仿真结果表明,二阶滑模变结构控制器的有效性和正确性,算法对负载和参数的变化具有很强的鲁棒性。  

二阶滑模控制在直流无刷电机转速调节中的应用

针对受参数不确定和负载扰动影响的直流无刷电机的鲁棒速度控制问题,采用二阶滑模控制中的超螺旋算法设计速度控制器。控制器将不连续控制作用在滑模量的二阶微分上,不但保持了传统一阶滑模的性能,而且消弱了系统抖振。仿真结果表明,算法对负载和参数的变化具有很强的鲁棒性,有效地消弱了传统滑模的抖振现象。  

Robust attitude tracking control for a rigid spacecraft under input delays and actuator errors

Attitude control of a rigid spacecraft under input delays, disturbances, parameter uncertainties, actuator errors, and constraints is a challenging problem. In this paper, these problems are considered simultaneously, and a robust control approach to attitude tracking of a rigid spacecraft is exploited. The design methodology is based on three steps: (1) compensating input delays by using the backstepping technique, (2) design of a disturbance observer for the delayed system by using the super-twisting algorithm to estimate unknown internal and external disturbances, then adding a feedforward compensation law based on the estimated signal to the backstepping controller to attenuate the effects of disturbances, (3) employing a robust least-square scheme to map the specified control command on the redundant actuators in the presence of actuator error, including actuator magnitude deviation and misalignment, with regard to actuator amplitude and rate constraints. The effectiveness of the proposed algorithm is shown by various numerical simulations.  

Adaptive disturbance observer‐based finite‐time continuous fault‐tolerant control for reentry RLV

The control effectors of reusable launch vehicle (RLV) can produce significant perturbations and faults in reentry phase. Such a challenge imposes tight requirements to enhance the robustness of vehicle autopilot. Focusing on this problem, a novel finite‐time fault‐tolerant control strategy is proposed for reentry RLV in this paper. The key of this strategy is to design an adaptive‐gain multivariable finite‐time disturbance observer (FDO) to estimate the synthetical perturbation with unknown bounds, which is composed of model uncertainty, external disturbance, and actuator fault considered as the partial loss of actuator effectiveness in this work. Then, combined with the finite‐time high‐order observer and differentiator, a continuous homogeneous second‐order sliding mode controller based on the terminal sliding mode and super‐twisting algorithm is designed to achieve a fast and accurate RLV attitude tracking with chattering attenuation. The main features of the integrated control strategy are that the adaptation algorithm of FDO can achieve non‐overestimating values of the observer gains and the second‐order super‐twisting sliding mode approach can obtain a more elegant solution in finite time. Finally, simulation results of classical RLV (X‐33) are provided to verify the effectiveness and robustness of the proposed fault‐tolerant controller in tracking the guidance commands. Copyright © 2017 John Wiley & Sons, Ltd.