球杆网络化控制系统的延时分析与控制方法研究  

Analysis of network-induced delay and control strategy based on Ball-Beam networked control system

作　　者：梁军[1] 桂卫华[1] 伍晓峰[1] 

机构地区：[1]中南大学信息科学与工程学院,湖南长沙410083

出　　处：《计算机与应用化学》2011年第7期883-886,共4页Computers and Applied Chemistry

基　　金：国家自然科学基金重点资助项目(60634020);国家自然科学基金资助项目(60804037)

摘　　要：对球杆系统进行了机理建模,并针对球杆网络化控制系统网络负载小、节点少、带宽冗余等特点,从网络通信原理的角度分析了网络延时的不确定性,结合测试结果提出了具有时变性、分段保持性延时特征的网络环境的假设。在这个前提下,将网络分布时延转换为前向通道上的单一时延。在此基础上提出了球杆网络化控制系统的根据延时分段补偿控制的策略及在线获取当前延时的方法,设计了PID-Smith动态延时补偿控制器对不同时延系统进行了控制,仿真结果表明该控制策略能够有效补偿网络延时,使系统能够在3s内稳定,克服由网络延时对系统控制品质造成的不良影响。The ball-beam system consists of a long beam which can be tilted by a servo or electric motor together with a ball rolling back and forth on top of the beam. It is a popular textbook example in control theory. The significance of the ball-beam system is that it is a simple system which is open-loop unstable. Even if the beam is restricted to be very near!y horizontal, without active feedback, it will swing to one side or the other, and the ball will roll offthe end of the beam. To stabilize the ball, a control system which measures the position of the ball and adjusts the beam accordingly must be used. In two dimensions, the ball-beam system becomes the ball and plate system, where a ball rolls on top of a plate whose inclination can be adjusted by tilting it frontwards, backwards, leftwards, or rightwards. When the data of the ball-beam system is transferred through the network, the system can be referred to as a networked control system. In this system, the scale of network nodes is small, the information flows smooth, and the network load is low. For control, the network-induced delay of the ball-beam system is the most concerned. After analysis, the time-varying but pieccwise constant delay is hypothesized. Then, the distributed delays are equivalently lumped together as a single delay. On the other hand, a method of delay-measuring is proposed. Based on that, a reasonable control strategy is designed. Compensating by Smith compensator, the ball-beam networked control system is simulated, and the result shows the effectiveness of the control strategy.

关 键 词：网络控制 球杆系统 时延补偿 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置] TP319[自动化与计算机技术—控制科学与工程]