Event-Triggered Fixed-Time Integral Sliding Mode Control for Nonlinear Multi-Agent Systems with Disturbances

In this paper, the leader-following consensus problem of first-order nonlinear multi-agent systems (FONMASs) with external disturbances is studied. Firstly, a novel distributed fixed-time sliding mode manifold is designed and a new static event-triggered protocol over general directed graph is proposed which can well suppress the external disturbances and make the FONMASs achieve leader-following consensus in fixed-time. Based on fixed-time stability theory and inequality technique, the conditions to be satisfied by the control parameters are obtained and the Zeno behavior can be avoided. In addition, we improve the proposed protocol and propose a new event-triggering strategy for the FONMASs with multiple leaders. The systems can reach the sliding mode surface and achieve containment control in fixed-time if the control parameters are designed carefully. Finally, several numerical simulations are given to show the effectiveness of the proposed protocols.     

基于ESO的装甲车辆稳瞄系统积分滑模控制

针对装甲车辆稳瞄系统中存在摩擦力矩、参数漂移等非线性扰动因素造成系统性能下降的问题,设计一种基于扩张状态观测器（ESO）的积分滑模控制策略。在基于状态变量的滑模面中引入了误差积分补偿项,有利于降低系统的稳态误差,同时突破了常规滑模控制中被跟踪信号的各阶导数均需已知的限制;利用ESO对系统内外扰动进行观测补偿,减小了滑模控制所需要的切换增益,削弱滑模控制容易出现的抖振现象。仿真及实验结果表明,跟踪精度保持在0.5％以内,系统最大稳定误差小于0.1 mrad,该控制策略能够很好地抑制各种非线性扰动因素的影响,有效地改善系统的控制性能。     

RCLSJ约瑟夫森结混沌系统的鲁棒自适应滑模控制

讨论了具有不确定参数和外界扰动的非线性电阻-电容-电流分路结模型(RCLSJ)混沌系统的广义控制问题。基于Lyapunov稳定性理论和滑模变结构控制方法,设计了鲁棒自适应滑模控制器,使得RCLSJ混沌系统能以任意比例因子追踪期望的参考信号。该方法不需要预先知道不确定参数和外界扰动的上下界,在控制器中引入一类简单的自适应律,用以在线估计参数和界值。该控制方法对参数不匹配和外界扰动具有较强的鲁棒性。数值仿真表明了该方法的有效性。     

Synchronization of different chaotic systems via active radial basis functions sliding mode controller

This paper presents a new method to synchronize different chaotic systems with disturbances via an active radial basis function （RBF） sliding controller. This method incorporates the advantages of active control, neural network and sliding mode control. The main part of the controller is given based on the output of the RBF neural networks and the weights of these single layer networks are tuned on-line based on the sliding mode reaching law. Only several radial basis functions are required for this controller which takes the sliding mode variable as the only input. The proposed controller can make the synchronization error converge to zero quickly and can overcome external disturbances. Analysis of the stability for the controller is carried out based on the Lyapunov stability theorem. Finally, five examples are given to illustrate the robustness and effectiveness of the proposed synchronization control strategy.     

一种新颖的滑模非线性比例积分混沌控制方法

一种新颖的滑模非线性比例积分控制方法（SMNPIC）被提出用于高精度驱动一类时变不确定混沌系统到任意期望轨道。SMNPIC区别于以前的滑模控制技术之处在于滑动模的一个非线性比例积分函数被包含在控制率中，因此不仅稳态误差和高频抖振都被减小，同时鲁棒性和快速性也能被保证。此外，SMNPIC实际上能被作为一类非线性PID控制器，不仅仅跟踪误差及其直到n-1阶微分被考虑，而且跟踪误差的积分也被考虑，因此有比传统PID更多的有用信息能被使用，因此更好的动静态特性能被获得。通过不确定Duffing-Holmes系统的仿真实例证实了SMNPIC用于混沌控制能获得好的性能。     

冠状动脉系统高阶滑模自适应混沌同步设计

针对冠状动脉系统混沌同步问题, 系统模型受到有界但未知的不确定干扰条件下, 利用几何齐次性理论和积分滑模面设计高阶滑模自适应控制器, 使响应系统在有限时间内跟踪驱动系统, 该方法无需提前预知扰动边界. 采用Lyapunov理论对闭环系统进行分析并证明该控制器保证该系统能够在有限时间内镇定, 从仿真实验结果可以看出所设计的控制器在不确定干扰的情况下系统具有良好鲁棒性和未知参数的自适应性, 为能够有效治疗心肌梗死等冠状动脉疾病提供了一定的理论依据.     

基于滑模变结构控制及预测跟踪的光电吊舱控制方法北大核心CSCD

光电吊舱在稳像和目标跟踪过程中存在摩擦力矩、不平衡力矩等干扰力矩,从而影响速度环响应精度;另一方面,吊舱视频跟踪器图像传输和处理造成的延迟也会造成跟踪滞后,因此必须进行延时补偿。提出基于预测跟踪的滑模变结构控制方法,采用微分预测跟踪器实现对视频跟踪器的延迟补偿,采用预测跟踪器估计出的目标运动角速率构成自适应补偿参数,以调整滑模变结构控制量,改进的滑模控制算法在补偿干扰力矩的同时抑制了抖振现象。仿真及实验结果表明:改进的控制方法能够有效补偿干扰力矩和跟踪器延迟造成的误差,相对于传统PID控制,其跟踪误差减小为原来的1/3,并且该算法已经在相关系统上得到应用。     

压电驱动快速反射镜的自适应反演滑模控制

由压电驱动器驱动的快速反射镜(FSM)广泛应用于各种精密稳定跟踪系统,FSM的控制精度决定了系统的跟踪精度。但压电驱动器具有严重的迟滞非线性干扰,针对这一缺点,应用自适应径向基RBF神经网络对迟滞干扰进行非线性逼近,并在此基础上结合滑模控制和反演法,设计了自适应反演滑模(ABSM)控制器。仿真实验表明,相对于滑模控制器,ABSM控制器的最大跟踪误差和均方根误差为分别降低了57.26%和52.53%,提高了FSM的控制精度。     

Distributed Consensus Tracking Control of Chaotic Multi-Agent Supply Chain Network: A New Fault-Tolerant,Finite-Time,and Chatter-Free Approach

Over the last years, distributed consensus tracking control has received a lot of attention due to its benefits, such as low operational costs, high resilience, flexible scalability, and so on. However, control methods that do not consider faults in actuators and control agents are impractical in most systems. There is no research in the literature investigating the consensus tracking of supply chain networks subject to disturbances and faults in control input. Motivated by this, the current research studies the fault-tolerant, finite-time, and smooth consensus tracking problems for chaotic multi-agent supply chain networks subject to disturbances, uncertainties, and faults in actuators. The chaotic attractors of a supply chain network are shown, and its corresponding multi-agent system is presented. A new control technique is then proposed, which is suitable for distributed consensus tracking of nonlinear uncertain systems. In the proposed scheme, the effects of faults in control actuators and robustness against unknown time-varying disturbances are taken into account. The proposed technique also uses a finite-time super-twisting algorithm that avoids chattering in the system’s response and control input. Lastly, the multi-agent system is considered in the presence of disturbances and actuator faults, and the proposed scheme’s excellent performance is displayed through numerical simulations.     

考虑模型不确定性和时延的静止无功补偿器自适应滑膜控制器设计

静止无功补偿器(static var compensator,SVC)不仅可以为电力系统提供无功支撑、稳定电压,其附加控制还可以有效提高系统暂态稳定性,但SVC模型参数的不确定性以及广域测量信号时延等外部干扰给附加控制器的设计带来很大的难度.提出了一种基于自适应滑模变结构理论的SVC鲁棒控制器设计方法,所设计控制器能有效提高系统暂态稳定性,并且其对于模型不确定性以及时延有较好的鲁棒性.首先根据区域惯量中心的运动方程建立了包含SVC的电力系统模型;然后将滑模变结构理论应用于电力系统模型中,求得SVC附加控制律,并通过自适应律优化控制器参数;最后通过四机两区域系统以及IEEE9节点系统对SVC控制器效果进行了仿真验证.结果表明,SVC自适应滑模控制器可以有效提升系统暂态稳定性,并且其性能优于传统的线性控制方法.     

Smooth control of HIV/AIDS infection using a robust adaptive scheme with decoupled sliding mode supervision

In this paper, a robust adaptive controller subject to decoupled sliding mode controller as a supervisory controller has been implemented on the HIV infection dynamic model. A five-state dynamic model of HIV is utilized which the measurement of the CD4+T cells and the viral load counts are necessary to estimate all its parameters. Decoupled sliding mode control is a variable structure controller having significant and appropriate features, such as best tracking and regulation performance and robustness and elevate the performance of the controller. Generally, due to the importance of applied treatment strategy to mitigate viral escape, sliding mode control is utilized in accordance with PI control to deliver necessary control inputs. To achieve the least possible chattering, effectual methods such as the transfer function is used. To update the gains of PI control, an adaptation law is then employed. The results demonstrate the suitable performance of the controller via providing proper tracking performance, and also, elimination of the chattering problem and decrease the time of treatment. The number of infected CD4+ T-cells and the number of free virus particles can be controlled in less than five days. The proposed controller is capable of controlling the dynamic behavior of the virus concentration for different patients with the same control scheme.     

滑模动态面控制在快速反射镜系统中的应用

针对快速反射镜系统在捕获、跟踪、瞄准过程中,由于外界环境以及音圈电机机械惯性和电磁惯性所引起的影响跟踪精度以及响应时间的不确定性干扰问题,提出了一种滑模动态面控制器(SMDSC)。此控制器引入跟踪微分器(TD)代替传统动态面控制中的一阶滤波器,改善了一阶惯性环节收敛速度和控制精度不理想的问题,另外控制器将滑模控制和动态面控制相结合,进一步提高了系统的抗干扰能力和跟踪精度。研究表明,设计的SMDSC与传统动态面控制、经典PID控制相比较,上升时间分别提高了62.5%、75%;调节时间分别提高了72%、88%;跟踪精度分别提升了75%、96%。     

基于滑模控制的室内移动机器人路径跟踪

为解决室内环境下移动机器人的路径跟踪问题,建立了移动机器人的数学模型,并构造一种新型滑模控制趋近律。采用该趋近律设计滑模控制律,并利用李雅普诺夫定理证明了系统稳定性。采用所设计的滑模控制器对室内移动机器人进行路径跟踪实验,仿真结果验证了该方法的有效性。     

基于补偿控制的无人地面车辆轨迹跟踪方法

针对无人地面车辆轨迹跟踪精度不高,鲁棒性差的问题,提出了一种基于补偿控制的算法。该算法分为运动学和动力学两部分：基于方向角调整策略的运动学控制律能确保无人地面车辆有效跟踪参考轨迹;基于PD与模型参考模糊滑模自适应控制相结合控制的动力学控制律能有效补偿建模不精确和外界扰动带来的影响。仿真结果表明：该算法能够有效跟踪参考轨迹,控制量分配合理且鲁棒性较好。     

Finite-time sliding mode synchronization of chaotic systems

A new finite-time sliding mode control approach is presented for synchronizing two different topological structure chaotic systems. With the help of the Lyapunov method, the convergence property of the proposed control strategy is discussed in a rigorous manner. Furthermore, it is mathematically proved that our control strategy has a faster convergence speed than the conventional finite-time sliding mode control scheme. In addition, the proposed control strategy can ensure the finite-time synchronization between the master and the slave chaotic systems under internal uncertainties and external disturbances. Simulation results are provided to show the speediness and robustness of the proposed scheme. It is worth noticing that the proposed control scheme is applicable for secure communications.     

基于模糊滑模的有限时间混沌同步实现

提出了混沌同步有限时间实现问题.应用全程滑模控制技术，选择指数型终端滑模趋近律来设计滑模控制器，以实现一类混沌系统的状态同步.该设计方案针对混沌系统的参数不确定性和外界扰动，引入模糊基函数网络，在线估计不确定性和外部扰动的界值.同时该方案消除了滑模控制的到达阶段，状态始终保持在滑模面上，并能在有限时间内趋近于原点.最后以Duffing系统为例研究验证同步策略的可行性和有效性.     

A target group tracking algorithm based on a hybrid sensor network

Traditional tracking algorithms based on static sensors have several problems. First, the targets only occur in a part of the interested area; however, a large number of static sensors are distributed in the area to guarantee entire coverage, which leads to wastage of sensor resources. Second, many static sensors have to remain in active mode to track the targets, which causes an increase of energy consumption. To solve these problems, a target group tracking algorithm based on a hybrid sensor network is proposed in this paper, which includes static sensors and mobile sensors. First, an estimation algorithm is proposed to estimate the objective region by static sensors, which work in low-power sensing mode. Second, a movement algorithm based on sliding windows is proposed for mobile sensors to obtain the destinations. Simulation results show that this algorithm can reduce the number of mobile sensors participating in the tracking task and prolong the network lifetime.     

改进的保群算法及其在混沌系统中的应用

混沌系统的跟踪控制是近年来非线性控制领域研究的热点之一. 本文提出了一种基于快速下降控制方法的保群算法, 此方法使受控混沌系统能够快速稳定到相空间的一个不动点; 另外提出一种基于滑模控制方法的保群算法, 此方法使受控混沌系统能够快速跟踪一个确定的运动轨迹. 应用这两种新方法分别对两个经典的混沌系统(Lorenz系统和Duffing系统)进行了相应的数值实验, 实验结果表明这两种方法都具用较高的精度和稳定性.     

基于不确定性变时滞分数阶超混沌系统的滑模自适应鲁棒的同步控制

针对一类含有不确定参数的时变时滞系统的同步控制问题,提出了一种滑模自适应鲁棒控制方法.基于Lyapunov稳定性理论和滑模自适应控制方法,设计出滑模自适应鲁棒控制器和参数自适应率.所设计的单一控制器适用于一类分数阶超混沌系统的同步性控制问题,它不仅具有较强的抗噪声能力而且对于时变时滞系统也具有良好的控制能力,因此该控制器具有较好的实用价值.此外,通过在系统的输入量中引入一个补偿量,用以消除系统中所存在的不确定性和外界扰动的影响,从而实现不确定性分数阶超混沌系统的同步,并且将系统的同步误差控制在任意小范围内.最后,对带有外界噪声扰动、系统参数不确定的时变时滞Chen分数阶超混沌系统进行了数值仿真,经过短暂的时间,响应系统与驱动系统同步,进而验证了所提出的控制方法的有效性.     

Robust synchronization and anti-synchronization of identical Φ6 oscillators via adaptive sliding mode control

The main goal of this paper is to propose the single input robust adaptive sliding mode controllers to accomplish synchronization and anti-synchronization between two identical Φ⁶ Duffing or Van der Pol oscillators with unmodel dynamics and external disturbances. Unlike directly eliminating the nonlinear dynamics by active control and sliding mode control in the literature, the proposed sliding mode controllers include the equivalent control part, which is only proportional to the synchronized error states, and the switching control part, where the discontinuous control functions have adaptive feedback gains. Sufficient conditions are provided based on the Lyapunov stability theorem and numerical simulations are performed to verify the effectiveness of presented schemes.