控制算法在自动浇注系统中的研究与仿真

【作者】 芦晓媛；

【导师】 李江涛；

【作者基本信息】 昆明理工大学 ， 检测技术与自动化装置， 2005， 硕士

【摘要】 浇注是现代化铸造生产中十分重要的方法和工艺过程。我国是一个铸造生产大国,各铸造企业为了使自己能在激烈竞争的市场中赢得一席之地,对铸件质量的要求越来越苛刻。然而许多因素影响或制约了铸件质量、产量的提高,甚至很多铸造企业依然停留在人工浇注阶段,虽然人工浇注的铸件质量比较好,生产效率却很低。作者通过对铸造过程中浇注系统的分析和研究,发现影响铸件质量的主要因素是浇注过程中浇口杯的液位。它的高低不仅影响着铸件的质量和产量,而且如果控制不好,液位过高,会导致金属液从浇口杯中漏出,破坏整个浇注系统的正常工作;液位过低,又会造成铸件中缩松、缩孔、气泡等现象,甚至导致残次品的产生。 浇注系统是一个非常复杂的被控对象,它具有非线性、时变性、灰色性等特点,简单的PID控制方式虽然能实现浇注的自动化,但存在一定的缺点,控制参数很难调整,而且需要有经验的操作工人在线不断地对这些参数进行调整,才有可能达到浇注这个复杂多变被控系统的工艺要求。这种控制方法控制效果和有经验操作工人的控制效果相比,铸件的质量和产量存在较大的差别,而且随着操作工人的不断变更,这些宝贵的操作经验知识也有可能会随着丢失。因此有必要给浇注系统引进一些新的控制方法,以满足铸造中浇注系统自动控制的要求,从而推动我国铸造业的发展。 本文是围绕铸造浇注系统中液位的控制问题而展开的。浇口杯液位控制是浇注系统中重要的环节,是铸造生产的核心。如上所述,它的控制直接影响到铸件的质量和产量。采用传统的控制方法又很难达到控制要求。在对浇注系统进行分析和研究的基础上,作者通过现场不断地手动浇注以及与有丰富操作经验的工人进行交流,收集了大量的浇注知识。针对现有自动浇注系统的特点,将这些操作知识进行归纳总结,提出采用模糊控制的方法,并在简单模糊控制和PID控制的基础上提出一种新的控制算法,较好地解决了这一问题,达到了工艺要求。 在设计模糊控制器的过程中,通过不断仿真试验,作者发现隶属度函数,控制规则,调整因子等因素,对自动浇注系统中模糊控制器性能更多还原

【Abstract】 Casting is a very important technique in modern casting. China is a big country for casting, all this kind of companies want to be successful in the hotly compete market, so the request to the cast is higher and higher, but there are many factors influence and restrict the improvement of the products. There are many factories still stay in the period of using workers to pouring, the result is that the quality is good, but the efficiency is low. The writer analyzed and studied the pouring system, found the key factor which influence the casts’ quality is the fluid-station in the pouring cup. It is too higher, will make the molten metal overflow and destroy the whole common manufacturing process; or it is too lower, will make inferior products.The pouring system is a complex object to be controlled, which has the character of non-linear, occasional and ashen. Although simple control method can realize the auto-pouring, it has some shortcomings, that is, with the declining of molten iron level in pouring bag, it can’ t response automatically to the change of the parameters of the controlled object, and need seasoned workers to adjust these parameters online, which is possible to reach the technical request. Compare the result with the seasoned workers’ , the quality is very different, and if the workers are different and changing, the operational knowledge will be lost. So it’ s necessary to in-troduce some new control method in the pouring system, in order to reach the technical request and impulse the development of the casting manufacturing in our country.This thesis is developed on an existing problem for the control of molten iron level in the casting system. The level of the pouring cup is the core in the casting procession; like what we said, the control will influence the quality and output of the production directly. It is very difficult to realize the control request if we just use traditional control methods. Base on the analyze and study, the writer constantly operate in the factory and communicate with the seasoned workers, collect a lot of operational knowledge, provide a fuzzy control based on the present existing problems inthe casting system, and combine the two control method to a new way to resolve the problem better, which realize the technical request.During designing the fuzzy control, the writer found the subject function, control rule, and adjusting-gene play very important roles to the capability of the controller, constantly correct these factors, emendate the controller which has been designed; chose the best factors which suit to the pouring system. Summarize the advantage and disadvantage in the traditional control and the fuzzy control, the writer design a new one which is a kind of controller can self-adjust parameters. At last, emulation proved that this control method has reached the respected control effect.更多还原