摘要
在工业生产中,液位控制占据着重要的地位,对产品的质量以及生产的安全有着重大的影响。液位控制作为一种均匀控制有2个矛盾的控制目标:既要求流出率的变化尽量平稳,又需要保证液位的稳定。并且,在设计液位控制器时,还要同时考虑它的设定值跟随特性以及干扰抑制特性。随着控制理论的不断发展,二自由度控制的概念被提出,并得到了迅速发展。应用二自由度控制的方法来控制液位不仅可以满足均匀控制的2个目标并且可以实现对设定值跟随特性和干扰抑制特性的解耦。本文首先对一种二自由度液位控制器进行了研究,分析了其工作原理以及参数整定的方法,讨论了模型误差以及死区时间对于控制效果的影响。而后,针对控制器参数解耦不完全的缺陷,通过将内模控制与二自由度液位控制器结合,提出了改进的二自由度控制方案,改进了控制器结构。根据新的控制器结构推导出了相应的参数整定方法,实现了控制器参数的完全解耦。同时,与原控制器相比,在保证均匀控制目标最优的情况下,改进控制器的参数整定更加简单,并且参数的调节更加灵活。最后,应用MATLAB对比了2种控制器的仿真结果,验证了改进控制器的控制效果。
Level control has occupied an important position in industrial process that it has significant effect on the quality of products and the safety of the production. As an average control, level control involves two conflicting objectives： changes in outlet flow rates should be as smooth as possible and at the same time level should remain stable. In addition, set point response and load response should also be considered when a level controller is designed. With the development of control theory, a two-degree freedom control is proposed and has been receiving considerable progress. Applying two-degree freedom control to control liquid level not only meets the objectives of average control, but also realizes the decoupling of set point response and load response. In this article, firstly a two-degree freedom level controller is studied by analyzing its working principle and parameter tuning method. Its performance when model error and dead time exist is also discussed respectively. Then combined with an internal model control, an improved control scheme and controller structure is presented aiming at remedying the defect that the parameters are not entirely decoupled. The corresponding parameter tuning approach is deduced which implements the complete decoupling of the parameters. Meanwhile, the parameter tuning of the improved controller is much easier and more flexible, comparing to that of the original controller, under the circumstance that the objectives of average control have received optimization. Finally, the simulation results of these two controllers using MATLAB are contrasted to demonstrate the performance of the improved controller.
出处
《计算机与应用化学》
CAS
2016年第1期54-58,共5页
Computers and Applied Chemistry
关键词
液位控制
二自由度
内模控制
level control
two-degree freedom
internal model control
