摘要
控制、计算机和网络通信是目前世界上三大热门的研究与应用领域,而三者的结合更是具有挑战性的研究课题。网络控制系统(Networked Control System,简称NCS)是这三种技术结合的成果,NCS给控制系统带来了崭新的一面,并且被迅速的应用到工业生产中。
网络控制系统的研究主要分为控制和网络两部分,控制衡量的是系统的网络控制质量,例如动态和稳态特性;网络衡量的是系统的网络服务质量,诸如调度,网络利用率,网络诱导延时等。通常研究NCS的方法是依据经典的控制理论,协同考虑网络对控制性能的影响。本文也是遵循这一原则进行研究分析网络控制系统的。文中主要利用MATLAB中相关的工具箱,研究网络控制系统的性能,控制器的设计以及采样周期的优化问题,实现NCS中控制与网络的协同设计,以实现NCS系统优化,并仿真验证了可行性。
本文首先介绍了网络控制系统中的常见的研究问题,例如,控制器的设计、调度,控制与网络的协同设计,采样周期优化,时延,数据包错乱,丢失等,它们是影响网络控制系统性能的因素,了解和解决这些问题是保证网络控制系统性能的关键。
然后,针对上面提到的网络控制系统中常见的研究问题,重点对控制器的设计进行了研究。根据经典的控制理论,闭环极点和控制系统的控制质量存在关系,作者给出了基于根轨迹的极点配置设计控制器的方法,并且通过MATLAB相关工具箱进行仿真验证,仿真结果表明控制器完全满足控制对象的要求。
最后,针对网络控制系统中的调度问题,以及控制与网络的协同设计、采样周期优化问题,给出了解决方案,完成网络控制系统的采样周期的优化,实现NCS整体性能的最优。
文章的创新之处在于,分别从控制和调度的角度分析了采样周期的约束,重点研究了采样周期的优化,提出一种新的优化采样周期的方法,利用MATLAB\OPTIMTOOL优化工具箱,优化采样周期,实现了控制和网络的协同设计。并利用MATLAB\TRUETIME网络仿真工具箱,设计仿真模型,仿真结果验证了经过优化采样周期,网络控制系统结构得到优化,网络的带宽实现利用率的最大化,性能在一定的约束下实现最优化。仿真结果表明,网络资源得到了合理的分配,并且控制性能满足要求。
Controlling, computer and network communication are the most popular research and application field in the world, while the combination of all three is a challenging research topic. Networked Control System (Networked Control System, NCS) is the achievement of the three kinds of technology. Not only has NCS brought controlling to a new field, but also it is quickly applied in industrial production.
The network control system is mainly divided into two parts, controlling and network. The control measures of dynamic and static characteristics of system, and network measures of service quality of system, such as designing controllers, scheduling, the collaborative of designing control and network, optimization of the sample rate, induce delay, packet loss, etc. Generally speaking, the method of study NCS is to collaborate control and network by classic control theory. This paper is also according to the principle. It is mainly using relaxed MATLAB toolbox to study the controller design problem and optimization sample rate, finally, the simulation result show that NCS is feasible.
This paper firstly introduces the network control system of common research problems, for example, the controller design, scheduling, collaboration with control and network, optimization of the sample period, packet loss, etc. They influence performance of network control system. So, understanding and solving these problems is the key to guarantee the performance of network control system.
Then, in view of the network control system's problems mentioned above, the author focuses on the controller design problem. According to classical control theory, there is a relationship between root locus and control quality of the control system. Based on the ralationship, the author gives a method to design a controller, and the simulation result shows that the controller is completely satisfied with the requirement of NCS.
Finally, referring to scheduling, collaboration of control and network, optimizing sample rate of the network control system, there gives resolution which realizes optimizing sample and achieves optimal performance in NCS.
The innovation of the paper is optimzation sample rate both considering control and network restraints, in conclusion lastly the simulation result verifies that the sample rate is optimal and the performance of NCS also meets the requriement.
引文
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