【作者】 王仁书；

【导师】 白焰；

【作者基本信息】 华北电力大学 ， 控制理论与控制工程， 2014， 博士

【摘要】 随着工业生产规模的扩大以及复杂度的增加,越来越多的控制系统采用分布式的结构,而且近些年来,无线技术在工业领域的应用范围也在不断扩大。在这两种发展趋势下,本文提出分布式自组织顺序控制系统(Distributed Self-organization Sequence Control System,DSSCS),并对其展开深入的探讨和研究。DSSCS利用无线节点的计算、存储和通信资源,以分布式的方式执行顺序控制逻辑,而且能够自动生成控制逻辑,提高了系统的自动化水平,对推动工业自动化的发展具有积极意义。本文中的DSSCS以无线网络为基础,无线传输中的延时和误码会导致系统产生完全错误的控制指令,造成严重后果。因此,需要设计相应的机制降低延时和误码造成的影响,而且还要保证系统的能控性和能稳定性。此外,传统组态方式效率较低而且容易出错,为了提高DSSCS的组态效率,设计一种面向生产过程的控制逻辑自组织生成方式。围绕上述DSSCS实现过程中的关键问题,本文取得如下的理论研究成果和创新点：1.提出了分布式自组织顺序控制系统(DSSCS)。DSSCS没有集中的控制器,控制逻辑完全分散到现场的无线控制节点上,以分布式的方式完成系统的控制任务。此外,系统还能以自组织方式生成控制逻辑,从而无需人工组态就能够自动生成控制逻辑。与传统的顺序控制系统相比,DSSCS具有明显的优点：分布式的系统结构消除了集中故障；使用无线网络传输现场信号节约了大量的线缆；控制逻辑的自组织生成方式提高了组态效率。2.分析无线传输中的延时和误码对DSSCS性能的影响,并设计降低影响的机制。利用确定与随机Petri网和时序Petri网,并引入复合标识对系统进行建模,用随机时间变迁表示无线传输延时,用冲突变迁之间的概率触发表示误码的发生,同时引入时序逻辑公式确定DSSCS中其余冲突变迁的触发条件,使系统能够按照指定的步序进行状态转移。通过建立的模型,分析系统可能出现的状态及其持续时间,判定系统的运行过程是否符合步序要求。针对传输中的误码提出状态限定的方法提高系统正确运行的概率,同时采用偏差补偿方法减小由无线传输延时造成的状态持续时间偏差,并通过仿真试验证明方法的有效性。3.利用布尔控制网络建立DSSCS的控制模型,并引入半张量积得到系统的状态关联矩阵,分析误码和延时对DSSCS能控性和能稳定性的影响。分析过程中,将误码导致传输状态的改变转化为控制节点选择不同的结构矩阵,从而得到不同的系统状态关联矩阵,并且将带延时的系统状态,根据延时的不同分解为不同的状态转移路径。基于系统可能出现的状态关联矩阵以及最长路径的长度,得到DSSCS在误码和延时影响下的能控性和能稳定性判据。在使用半张量积的同时,提出面向生产过程的控制逻辑自组织生成方式,通过面向生产过程的操作,使分散的控制节点自动确定表示控制逻辑的结构矩阵,形成一个有组织、协同控制的顺序控制系统,而且在更换无线节点的过程中,系统也能对分布式控制逻辑进行自动维护。4.在电站化学水处理车间内超滤系统的顺序控制中实现基于无线网络的DSSCS。根据实际生产的要求,构建系统的整体框架,设计无线网络信息共享、控制逻辑自组织生成、分散控制、分层诊断、实时监测功能,并兼顾无线网络的低功耗设计,实现安全、可靠、低功耗的DSSCS。同时,给出无线DI/O模块、基站的软硬件设计原理,并展示了DSSCS在现场的应用情况。更多还原

【Abstract】 As the expansion of the scale and the growth of the complexity of industrial production, the distributed structure is adopted in more and more control system. Besides that, the scale of the application of wireless technology in industrial field has been enlarged constantly in recent years. Given these trends, a distributed self-organization sequence control system (DSSCS) is proposed and discussions and research are carried out in-depth. In DSSCS, the resource of computation, memory and communication is utilized to not only execute the sequence control logic in a distributed manner, but also generate the control logic automatically. It improves the level of automation of the system and bears positive significance for the development of industrial automation.For the realization of DSSCS is based on wireless network, the delay and bit error in wireless transmission may lead the system to generating totally wrong control command, resulting in serious consequences. So related mechanisms have to be designed to reduce the influence caused by delay and bit error and the controllability and stabilizability of the system should be also guaranteed. In addition, for the traditional manner of configuration is of inefficiency and fallibility, to improve the configuration efficiency of DSSCS, the generation of control logic in self-organization manner which is production-oriented is designed. Around the above critical problems in the realization of DSSCS, the theoretical research results and innovative points achieved in this paper are summarized as follows:1. A Distributed Self-organization Sequence Control System (DSSCS) is proposed. There is no centralized controller in DSSCS and the control logic is totally dispersed into the wireless control nodes in field, executing the control tasks in a distributed manner. Besides that, the system can generate the control logic in a self-organization manner, so that the control logic can be generated automatically without artificial configuration. Compared to the traditional sequence control system, DSSCS has distinct advantage, such as the centralized fault is eliminated by adopting distributed structure, lots of cable is saved by using wireless network for signal transmission and the configuration efficiency is improved through the manner of self-organized generation of control logic.2. Analyzing the performance of DSSCS affected by delay and bit error in wireless transmission and designing the mechanisms reducing the influence. The deterministic and stochastic Petri net and temporal Petri net are combined to model the work process of DSSCS with the complexed marking introduced. The delay in wireless transmission is presented by the transition with randomly distributed firing time and the occurrence of bit error is simulated by the probabilistic firing between the conflicted transitions. To make sure that the states of the system are transferred according to the given sequence steps, temporal logic equations are introduced to determine the firing condition of other conflicted transitions in DSSCS. Based on the derived model, the possible states and their durations can be analyzed, so that it can be confirmed whether the operation of the system meets the requirement of the given steps. Considering the bit error in transmission, the method of state restriction is proposed to improve the probability that the system operates correctly, meanwhile the deviation compensation is presented to minimize the deviation of the duration of the states. And the simulation results are also presented to show the improvement.3. Using Boolean control network to build the control model of DSSCS, with semi-tensor product introduced, the state incidence matrix of the system is obtained to analyze the controllability and stabilizability of DSSCS affected by bit error and delay. In the analysis, the problem of the altered states caused by bit error is transformed as that the control nodes choose different structure matrices and different state incidence matrices of the system will be derived. And the system states with delay are decomposed into different state transition paths according to the value of delay. Based on the possible structure matrices and the length of the longest path, the criteria of the controllability and stabilizability of DSSCS affected by bit error and delay can be derived. Besides that, by using semi-tensor product, the self-organized generation of control logic which is production-oriented is proposed. So, the distributed control nodes can automatically generate the structure matrices which denote the corresponding control logics through the operation based on production process, forming an organized sequence control system with cooperative control. Moreover, the control nodes can automatically maintain the distributed control logics in the situation that the nodes are replaced.4. DSSCS based on wireless network is applied for the sequence control of ultrafiltration system of chemical water treatment in power plant. According to the requirement of practical production, the overall framework is constructed and several functions are designed, such as information sharing, control logic generation in self-organized manner, distributed control, hierarchical diagnosis and real-time supervision with the low-power design for wireless network considered, to realize a DSSCS with safety, reliability and low-power dissipation. In addition, the design principles of the hardware and software of wireless DI/O modules and base station are presented. And the application of DSSCS in the field is exhibited.更多还原