【作者】 杨俊；

【导师】 宋锦春；

【作者基本信息】 东北大学 ， 机械电子工程， 2009， 硕士

【摘要】 本文根据冶炼工艺的要求,针对民用和国防工业具有重大意义的大型电渣炉设计了与之匹配的液压系统,并进行了主要元件的选择计算,同时对设计出的液压系统进行了执行元件强度稳定性与发热温升的校核。建立了具有普遍意义的非对称阀控制非对称缸的系统模型,并在此基础上得出了对称阀控制非对称缸的状态方程。对存在皮囊式蓄能器的系统也建立了相应的模型。本文应用内模(IMC)原理,得到了PID控制器参数与系统参数的关系,因而设计出的控制器能很好地与系统匹配。为了弥补PID控制器响应慢的不足,本文应用模糊控制原理,设计了模糊自整定PID控制器。模糊能够使用模糊规则,在线自动调整PID控制器的参数,缩短系统的响应时间。还提出了比例—模糊PID复合控制的方法。其基本原理是根据专家经验和系统调试时的现场状况,设定一个开关域值,作为切换不同控制器的触发信号。当系统偏差较大时用比例控制快速减小偏差。系统偏差变小后,应用模糊自整定PID提高控制精度。这样可以减少在线计算量,自动调整控制参数,使得动态性能得到极大改善。仿真结果显示,比例—模糊PID复合控制相对于常规PID其响应时间大大减少,完全可以成功地应用到工业产品中。实际系统运行时总存在一定的干扰。根据系统方框图的理论分析也表明,负值负载会对系统产生强烈的干扰。为了减小干扰信号对的影响,本文采用了针对干扰的前馈控制原理对干扰信号进行了一定程度的补偿。仿真结果表明,在工程误差允许的范围内,前馈控制能够补偿干扰信号产生的稳态误差,使系统正常工作。为了降低比例阀的制造成本,比例阀有一般在20%-30%的零位死区。这使得在闭环控制时系统在比例阀零位左右基本不能正常工作。为了使系统在零位左右依然有正确的输入输出关系,本文对比例阀的死区进行了一定程度的补偿。其基本原理是当给定信号进入了死区时,此时在控制器输出的基础上,增加补偿信号。补偿信号的大小基本由死区决定。仿真结果表明,采用补偿算法后,输出信号基本能够跟踪输入信号,即降低了比例阀的死区对系统的影响,使系统快速穿过了比例阀的死区。蓄能器是一种重要的液压系统辅件。它具有存贮能量、吸收冲击等多种功能。本文根据已经建立好的蓄能器工作模型,研究了蓄能器对系统的影响。从仿真结果可知：在参数恰当的条件下,蓄能器可以有效地吸收由于系统突然启停和液压阀换向引起的压力冲击,大幅度降低瞬时压力峰值,延长系统其他元件的使用寿命。这也是与理论分析和工程经验相吻合的。更多还原

【Abstract】 Electroslag Remelting (ESR) is an important special metallurgical methods. It is used in the production of national defense industry and civilian industry important parts. After the electroslag refining,high purity steel with compact organization need not the surface processing basically. Furthermore, ESR can easily produce titanic ingots, meeting the requirements of large forgings in industrial production. Increasing capacity of electroslag furnace makes a lot of control problems for the concerns of engineers and technicians.Transmission system is indispensable part of the equipment,which is responsible for the implementation of power transmission components from the prime mover. In the ESR process, as with the melting, the electrodes continue to shorten while the steel ingot increases gradually. In order to ensure the stability of melt-speed and current settings the electrode height needs to be adjusted in real-time. At the same time, the distance between the metal surface and the bottom electrode directly determining the value of the slag resistance, in order to ensure the power entering the slag pool, the electrode position with the mold needs to be adjusted to stabilize the melting current as well. It is a good choice to use the hydraulic system with low inertia and high ratio power as transmission control system to ensure the location parameters rapid adjustment and accurate positioning.Large-capacity electroslag furnace to drive a large load, this increases the inertia of the system, moreover in precise adjusting the parameters, the system will have a negative load interference. In addition, the proportional valves have large zero dead zone in order to reduce manufacturing costs. When the system stability has been ensured, meanwhile, how to balance speediness and accuracy is the issue of in-depth study in this paper.Simulation studies through a variety of control algorithms have shown that fuzzy control of the non-overload basically, short response time, is better than conventional PID. In this paper, fuzzy self-tuning PID and PID compound control are chosen by Switch Module. PID application can make the system with great deviations quickly close to a given position. Fuzzy self-tuning PID control is applied to improve accuracy when the systematic deviations become smaller. This can reduce the online calculation and automatically adjust control parameters which have greatly improved dynamic performance.更多还原