【作者】 韩安太；

【导师】 王树青；

【作者基本信息】 浙江大学 ， 控制科学与工程， 2007， 博士

【摘要】 利用无线通讯网络实现地域上分布的、可移动的现场传感器、控制器及执行器之间的信息相互交换，以达到被控对象的实时反馈控制，这样一类被称为“无线网络控制系统”的新型控制系统近年来得到了广泛的关注。与传统的点对点控制系统或有线网络控制系统相比，基于控制技术、网络技术、射频通讯技术和计算机技术实现的无线网络控制系统具有可实现资源共享、高的诊断能力、高度移动性、减少系统布线、增加系统的柔性和鲁棒性、安装维护方便等诸多优点，可在众多领域应用，成为控制领域的研究热点之一。然而，无线网络中的随机延时、丢包、低通讯带宽、通讯约束等问题也使无线网络控制系统的分析和设计变得异常复杂。本文针对一类在无线传感器网络基础上实现的无线网络控制系统，结合现代控制理论和射频通讯理论，通过实验和仿真对这类无线网络控制系统进行了研究，着眼于提高闭环控制系统的稳定性、减少网络延时对闭环控制系统性能的影响，从控制和网络两个角度提出了新的延时补偿算法。本文的主要工作如下：1．设计了一种基于IEEE 802.15.4／Zigbee通讯协议的、可用于无线网络控制系统和无线传感器网络研究的实验平台。该实验平台有助于理解无线网络控制系统，为本文的后续研究提供理论验证手段，同时，也给网络控制算法、实时调度算法、路由协议算法等理论研究者提供一种实际的算法验证平台。2．分析了利用IEEE 802.15.4／Zigbee通讯协议所实现无线网络控制系统中延时的组成，在此基础上，以实验手段探讨了不同网络因素对网络控制系统延时的影响。研究结果表明，为了减少网络延时，需要综合分析考虑采样周期、传输路由、信道条件、信号质量等因素。3．提出了一种基于Takagi-Sugeno模糊模型的简化模糊控制算法，并将其应用在基于无线传感器网络实现的直流无刷电机控制系统实验平台上，分析了网络的存在对控制系统的影响。在此基础上，对所提出的简化模糊控制算法进行了改进，改进后的控制算法可有效补偿随机网络延时对控制系统的影响。4．针对一类具有随机网络延时的无线网络控制系统，通过将网络延时作为模糊规则的前件变量，提出了一种新的基于Takagi-Sugeno模糊模型的网络控制系统建模方法；在此基础上，通过分析实时输入与模糊模型之间的映射关系，对模糊模型进行了简化；利用Lyapunov稳定性分析理论和线性矩阵不等式等工具推导了闭环网络控制系统的可镇定条件，进而设计了相应的模糊状态反馈控制器。5．考虑一类基于无线网络实现闭环的控制系统，分析了无线传感器网络中采用的多跳射频通讯方式对系统延时的影响；针对这种具有可变延时的闭环网络控制系统，提出了一种基于客户机-服务器模型的LQR输出反馈控制策略，并利用文献结论和线性矩阵不等式等工具，将闭环系统转换为一个切换控制系统，推导了系统的稳定性条件，在此基础上，给出了控制器的参数优化办法。6．针对基于无线传感网络实现的无线网络控制系统，从网络通讯的角度分析了网络延时的组成，在此基础上，提出了一种实现最小网络延时的路由算法，对路由算法的设计和实现进行了详细叙述。最后，对全文进行了概括性总结，提出了理论和应用上有待进一步深入研究的问题。更多还原

【Abstract】 A great deal of attention has recently been focused on a class of wireless networked control systems (WiNCS) where the control loops are closed through wireless communication networks. This family of systems is an integration of plants, sensors, controllers, actuators and wireless communication networks of certain local field. It aims to ensure data transmission and coordination manipulation among spatially distributed and mobile components. Compared with conventional point-to-point control systems and wired networked control systems, the advantages of WiNCS based on the control, network, radio frequency communication and computer technology are the elimination of wiring, lower install cost, greater mobility as well as greater agility and robustness in diagnosis and maintenance. Because of these distinctive benefits, these WiNCS are uesd in various fields, such as automotive, mobile robotics, advanced aircraft, mechanical and process control, and so on. The WiNCS becomes a hotspot in the control field.However, the introduction of wireless communication networks in the control loops makes the analysis and design of WiNCS complex. The requirements of stable feedback control with wireless network are not yet satisfied duo to random network-induced delays, higher bit-error, jitter, packet losses as well as limited communication bandwidth.In this dissertation, the WiNCS in the frame of modern control theory and radio frequency communication theory are studied through experimental methods for a class of WiNCS built around wireless sensor networks (WSN). With an aim to improve the stability of closed-loop WiNCS and decrease the impact of the network-induced delay on closed-loop WiNCS, the novel algorithms compensated the network-induced delay are presented from the viewpoint of control and wireless networks.The main research works are as follows:1. Based on the IEEE 802.15.4/Zigbee protocols stack, a novel prototype testbed is designed and used to study the WiNCS and WSN. The testbed can help to develop a thorough understanding of WiNCS and to verify the validity of the research results in this dissertation, also serves as a very useful tool for theoretical researchers on networked control, real-time scheduling and routing algorithm.2. For the WiNCS based on the IEEE 802.15.4/Zigbee communication protocols stack, the different time delay components of the total round-trip time delay in this WiNCS are identified. The experimental studies on a WiNCS prototype testbed are used to analyze the impact of the various factors on the total round-trip time delay. The results indicate the need for compromise between the selected sampling period, routing, condition of the channel, quality of the radio frequency signal and the network’s throughput.3. The novel simplified fuzzy control algorithm is proposed based the Takagi-Sugeno fuzzy model and applied in networked brushless direct current motor control system built on the WSN. The experimental results are used to analyze the impact of the wireless networks on closed-loop control system. Based on the analysis results, the simplified fuzzy control algorithm are improved in order to compensate the random network-induce delay.4. For a class of WiNCS with random network-induce delay, the new fuzzy model are presented based the Takagi-Sugeno fuzzy model, in which the random network-induce delay acted as the premise variable. Based on the fuzzy model, it simplifies the fuzzy model through searching the dominant fuzzy sub-system related to the real-time input variables, then the stabilizing problem is studied for a class of WiNCS based the above model simplified algorithm, the conditions of stabilizing closed-system are derived and the stabilizing fuzzy state feedback controller is designed through Lyapunov stability analysis theory and linear matrix inequality respectively.5. For a class of WiNCS based on the multi-hopping radio frequency communication technology, the number of hops necessary for data packets to reach their destinations is variable and affects the network-induced delay. To deal with these variable time delay, an LQR output feedback control scheme is introduced based on the client-server architecture. Because of the controller parameters adjusted according to the number of the hops, the closed-loop WiNCS can be converted into the switched control system, then the conditions of stabilizing closed-system are derived and the parameter optimal procedure of the controller is introduced through Lyapunov stability analysis theory, linear matrix inequality and the result of literatures respectively.6. From the viewpoint of the wireless networks, the sources of network-induced delay are identified for a class of WiNCS built on the WSN. Because the routing severely affect the total round-trip time delay in this WiNCS, a novel routing algorithm that can minimize the total round-trip time delay is proposed, the detailed implementation of the algorithm is introduced.Finally, we summarized the dissertation and suggested some open problems in theory and application.更多还原