基于流量自相似性的网络队列管理算法

网络流量的自相似性会导致数据突发状态持续,传统队列管理算法无法对网络流量突发状态进行预测,从而影响网络端到端时延、丢包率和吞吐性能。针对该问题,提出一种基于网络流量预测的主动队列管理算法P-ARED。基于网络流量的均值和方差给出网络流量等级的概念,讨论网络流量等级转移概率与Hurst参数之间的关系,提出基于贝叶斯估计思想的网络流量等级预测方法。在此基础上,在对自相似网络流量环境下的平均队列长度、缓存队列长度最小阈值等参数优化设置的基础上,基于Hurst参数和自相似流量等级预测结果,重新设计ARED算法中分组丢弃概率的计算方法,以提高缓存队列长度的稳定性。仿真结果表明,P-ARED算法与对比的主动队列管理算法相比,降低了网络端到端时延和丢包率,提高了端到端吞吐性能,其中平均吞吐量最高提升7.63%,平均时延最多降低17.52%。     

基于网络的运动控制系统预测控制研究

针对一类基于网络的运动控制系统中存在的时延和丢包问题进行研究。对于网络运动控制系统存在数据时延和丢包的情况,建立网络运动控制系统模型。在此模型下,对预测函数控制算法进行分析,设计了预测函数控制产生器和数据延时预测补偿器,并研究相应的补偿策略。仿真分析表明算法的合理性和有效性。     

具有一步随机时滞和多丢包的网络系统H∞滤波器设计

在网络系统中由于连接传感器和滤波器的网络带宽有限,系统测量数据在传输中会出现随机时延甚至丢失. 本文讨论了具有一步随机时延和丢包的网络系统的H∞滤波器设计问题.基于新近提出的同时描述随机时延和丢包的模型,利用线性矩阵不等式方法设计线性滤波器,使得滤波误差系统均方指数稳定,并具有给定的H∞性能. 滤波器参数通过求解一个线性矩阵不等式得到.仿真研究说明了所提出算法的有效性.     

基于Internet的遥操作系统带观测器的反馈控制

通常遥操作系统主、从机械手间存在通信时延,影响了系统的稳定性和操作性能.在基于Internet的遥操作系统中,时延是时变的,对系统的影响尤为剧烈.为了解决这个问题,在环境模型未知的条件下,首先提出在本地控制端用主手状态、预测的从手状态及接触力设计反馈控制器;接着用时间前向观测器预测从机械手的状态,并将时延变化率建模为系统不确定参数,最终得到稳定性和透明性条件.仿真结果表明了该方法的有效性.     

网络控制系统的预测补偿

针对网络控制系统中存在长时延和数据丢包的情况,通过在控制器节点前设置缓冲器,并设计预估控制产生器和时延补偿器,提出了一种预测补偿控制方案,有效地克服了长时延、数据丢包和时序错乱问题对实际网络控制系统稳定性所造成的影响．证明了采用上述控制方案时闭环网络控制系统的稳定性,最后提供的仿真实例验证了该控制方案的有效性．     

DoS攻击下的信息物理系统事件触发预测控制设计

针对信息物理系统(CPS)安全控制设计问题,提出拒绝服务(DoS)攻击下具有任意有界丢包的事件触发预测控制(ETPC)方法.首先,考虑DoS攻击能量的有限性及攻击行为的任意性,将DoS攻击描述为事件触发通信机制下的任意有界丢包;其次,在控制器端利用最近一次收到的状态信息进行控制器增益序列的预测设计以补偿DoS攻击造成的数据包丢失;随后,基于Lyapunov稳定性理论及切换系统分析方法考虑了DoS攻击下CPS的安全性并给出了控制序列设计方法.所提出的ETPC设计方法只需利用最近时刻收到的状态信息,无需满足传统CPS稳定性对最大允许丢包数的约束,为大时滞CPS的稳定性分析及控制提供了有效的解决方案.最后,通过仿真实例验证所提出的基于事件触发预测控制设计方法的有效性.     

基于虚拟拓扑的低轨卫星路由切换算法仿真

针对低轨卫星网络中星地链路、星间链路的不断切换会造成路由重构,而星地路由重构时间过长将严重影响数据传输时延稳定性的问题,提出一种卫星路由切换算法.算法结合了卫星网络拓扑可预测性和地面电台动态性的特点,在动态路由计算的过程中加入静态可预测信息以降低动态路由的计算开销,并基于OPNET搭建了一个低轨卫星系统仿真平台来验证该协议.仿真结果表明,上述协议能有效的解决低轨卫星系统路由重构的问题,降低了丢包率,减少了系统端到端时延.     

一类具有数据包丢失的长时延网络控制系统的分析与设计

针对一类网络控制系统,其网络诱导时延大于采样周期且存在数据丢包,研究了其稳定性和控制器的设计.在控制器端设计了一个状态预测器,其预测状态根据传感器的数据进行更新,然后用来确定控制作用.分析了预测误差的收敛性,证明了分离原理是成立的,并依据分离原理分别设计了状态预测器和控制器,给出了参数化设计方法.仿真例子验证了方法的有效性.     

具有多传输通道系统的网络化预测控制

本文研究了一类具有多传输通道网络化系统的控制问题,基于网络化预测控制方法,提出了一种改进型的分布式预测补偿方式,从而更有效地利用反馈数据来提高控制系统的性能.对闭环网络化预测控制系统进行分析,得到其稳定性条件,特别地,在模型精确已知和多传输通道的时延为定常的情况下,该条件将会退化为本地控制的闭环系统稳定性条件.上述结论的好处是网络化预测控制系统中状态观测器和控制器的设计可以参考本地控制.通过球杆系统算例验证本文所提方法的正确性和有效性.     

时延加权融合技术的无线传感器网络控制

本文研究了无线传感器网络控制系统的建模、稳定性与控制器设计问题.首先建立一个新的无线传感器网络控制系统模型,然后提出一种用于多个传感器数据融合的时延相关加权均值方法,并通过系统建模及分析,把无线传感器网络控制系统稳定性问题转换成为具有多个传输时延和丢包现象的多传感器单控制器网络控制系统稳定性问题.并利用线性跳变系统理论...     

基于距离传感器的双边遥操作

为了改善双边遥操作的力反馈性能,本文根据从端操作臂上的传感器检测的目标距离信息,设计了新 的PD 双边控制器．证明了系统的稳定性条件,并通过单自由度双边遥操作实验系统,对提出的控制方法进行了实 验验证．实验结果表明,当从端操作臂靠近目标时,主端操作臂产生了逐渐增大的反馈力．这种控制策略为操作者 安全实现遥操作任务提供了有效手段．     

Integrated adaptive robust control for multilateral teleoperation systems under arbitrary time delays

With the increasing industrial requirements such as bigger size object, stable operation, and complex task, multilateral teleoperation systems extended from traditional bilateral teleoperation are widely developed. In this paper, the integrated control design is developed for multilateral teleoperation systems, where n master manipulators are operated by human to remotely control n slave manipulators cooperatively handling a target object. For the first time, the control objectives of multilateral teleoperation including stability, synchronization, transparency, and internal force distribution are clarified systematically. A novel communication architecture is proposed to cope with communication delays, where the estimated environmental parameters are transmitted from the slave side to the master, to replace the traditional environmental force measurement in the communication channel. A kind of nonlinear adaptive robust control technique is used to deal with nonlinearities, unknown parameters, and modeling uncertainties existing in the master, slave, and environmental dynamics, so that the excellent tracking performance is achieved in both master and slave sides. The coordinated motion/force control is designed in the slave side by the optimal internal force distribution among n slave manipulators, and the impedance control is designed in the master side to realize the target transparency behavior. In summary, the proposed control algorithm can achieve the guaranteed robust stability, the excellent synchronization and transparency performance, and the optimal internal force distribution simultaneously for multilateral teleoperation systems under arbitrary time delays and various modeling uncertainties. The simulation is carried out on a 2‐master/2‐slave teleoperation system, and the results show the effectiveness of the proposed control design. Copyright © 2015 John Wiley & Sons, Ltd.     

化学反应器温度跟踪预测函数控制的研究及应用

对以预测函数控制算法为核心并结合PID控制的先进控制算法进行了研究,针对化学反应器的温度跟踪控制问题,给出了透明控制算法及预测函数控制器的具体形式,仿真结果表明,该算法具有较好的跟踪特性,抗干扰能力及鲁棒性,同时,该算法在SUPCON-JX300集散控制系统上实现,工业现场运行取得了很好的结果。     

Human control model in teleoperation rendezvous

This paper proposes a human control model in teleoperation rendezvous on the basis of human information processing （perception, judgment, inference, decision and response）. A predictive display model is introduced to provide the human operator with predictive information of relative motion. By use of this information, the longitudinal and lateral control models for the operator are presented based on phase plane control method and fuzzy control method, and human handling qualities are analyzed. The integration of these two models represents the human control model. Such a model can be used to simulate the control process of the human operator, which teleoperates the rendezvous with the aid of predictive display. Experiments with human in the loop are carried out based on the semi-Physical simulation system to verify this human control model. The results show that this human control model can emulate human operators＇ performance effectively, and provides an excellent way for the analysis, evaluation and design of the teleoperation rendezvous system.     

工业机器人遥操作系统的空间映射与控制策略

针对工业机器人遥操作系统中存在的主从机器人工作空间差异以及运动控制精度与安全问题,提出了一种工作空间映射算法与位置—速度混合控制策略。首先,将遥操作划分为自由运动和交互两个阶段,在自由运动阶段采用映射算法使主从机器人的工作空间高度覆盖,使主机器人可操控的从机器人运动范围最大化。进一步,在交互阶段设计了一种位置—速度混合控制策略对工业机器人的运动进行准确的控制,使主从机器人的实际位置轨迹准确的跟随,并进一步引入反馈引导力以实现安全的控制。最后在Touch-ABB IRB120主从机器人遥操作实验平台上对所提控制方法进行验证,实验结果表明该方法使得主从机器人运动范围在高度覆盖的同时可以保证遥操作控制的精度。     

Observer-based sliding mode control for bilateral teleoperation with time-varying delays

In this paper, a tracking control scheme is investigated for a bilateral teleoperation system with time-varying delays and dynamic uncertainties. The tracking control scheme is based on an extended state observer (ESO), a time-delay part observer and a continuous terminal sliding mode control (CTSMC) strategy. The dynamic uncertainties are dealt with by the ESO for the bilateral teleoperation system. The time-varying delays with unmeasurable derivatives are estimated by the two time-delay part observers. The CTSMC strategy is used to ensure finite-time convergence for the bilateral teleoperation system without knowing the second derivatives of tracking errors. Finally, experiment results are shown for the bilateral teleoperation system to demonstrate effectiveness of the developed tracking control scheme.     

基于操作者表现的机器人遥操作方法

针对遥操作机器人,提出了一种操作者表现（PoT）的在线识别方法以及基于PoT的遥操作移动机器人控制框架.首先,通过分析遥操作者的EEG（脑电信号）获得5个PoT指标,并使用BP（反向传播）神经网络对其进行建模,从而实现对遥操作者表现的在线识别.随后,设计了一种基于PoT动态调节遥操作共享控制系统中的控制权重的策略.选取3名不同遥操作者进行了在线PoT识别及基于PoT的共享控制遥操作实验,实验结果证明该方法能够有效地在线识别PoT,同时基于PoT的控制框架提升了遥操作的效率和安全性.     

Model Predictive Control for Transparent Teleoperation Under Communication Time Delay

Prior efforts in bilateral teleoperation under communication delay have mainly yielded control algorithms that sacrifice performance in order to guarantee robust stability. In contrast, this paper proposes a multimodel predictive controller that can enhance the teleoperation transparency in the presence of a known constant delay. Separate controllers are designed for free motion/soft contact and contact with rigid environments, with switching between these mode-based control laws occurring according to the identified contact mode. Performance objectives such as position tracking and tool impedance shaping for free motion/soft contact, as well as position and force tracking for contact with rigid environments, are incorporated into a multi-input/multi-output state-space representation of the system dynamics. New Artstein-type state and measurement transformations are proposed to generate delay-free dynamics suitable for output-feedback control, based on the original dynamics with delays in various input and output channels. The application of the continuous-time linear quadratic Gaussian control synthesis to the resulting mode-based delay-free dynamics yields control laws that guarantee closed-loop stability and enhanced performance in each phase of teleoperation. The robustness of the mode-based controllers with respect to parametric uncertainty is analyzed. Experimental results with a single-axis teleoperation setup demonstrate the effectiveness of the proposed approach     

预估控制下的实时网络遥操作移动机器人

构建了能使操作者通过Internet远程实时控制的移动机器人系统．为了补偿网络时延和抵消其对遥操作系统的影响,基于我们以前提出的改进型Smith预估器原理,采用了预估控制策略．为了保证系统稳定性和透明性,基于主从端的传感器信息交换,设计了一个动态模型管理器,其中模型和力反馈误差调节通过模糊控制实现．除了力反馈外,为了增强遥操作的实时性,引入了预估的虚拟显示．为了精确地预测网络时延,提出了一个新颖的时钟同步算法．为了降低时延抖动,结合我们提出的两个算法,实现了数据缓冲策略．最后,通过长距离的网络遥操作实验验证了系统和控制策略的实用性和有效性．     

Robust Output Feedback Controller Design for Time‐Delayed Teleoperation: Experimental Results

In this paper, a robust output feedback control strategy is proposed for a nonlinear teleoperation system which can deal with stability as well as transparency despite the variable time‐delay and uncertain dynamics. The proposed approach is composed of two steps. First, local Lyapunov based adaptive controllers are applied to both master and slave sides in order to suppress the nonlinearities in the system dynamics. Afterwards, a new observer‐based controller scheme is proposed to achieve stability and performance (transparency) of the teleoperation system. Using the Lyapunov techniques, stability and performance objectives are cast as some linear matrix inequality (LMI) feasibility conditions. To evaluate the performance of the proposed controller, a set of simulations and experiments are performed. Through simulation results, it is demonstrated that the proposed approach significantly outperforms the existing methodologies reported in the literature.