【作者】 王威；

【导师】 高宪文；

【作者基本信息】 东北大学 ， 控制工程， 2011， 硕士

【摘要】 焦炭是冶金工业炼铁的主要原料,炼焦生产过程中同时伴随产生大量的副产品荒煤气。集气过程回收利用副产煤气,不仅节约能源,而且降低环境污染,是钢铁生产的重要环节。集气管压力稳定与否,影响到煤气质量、设备寿命以及生产环境。研究多焦炉集气过程控制对钢铁工业生产有着重要的意义。多焦炉集气过程是一个高度复杂的工业过程,具有多变量强耦合、不对称、非线性、时变等控制难点,用常规控制方法难以达到有效控制。本文在综合考虑焦炉集气管压力系统的物理、工艺特点的基础上,主要研究了集气管压力的机理建模方法及非线性多模型预测控制算法在其控制上的应用。首先,针对集气管系统扰动变化剧烈、非线性等特点,在分析焦炉集气管压力系统物理特性及工艺特点后,建立集气管压力的机理模型,通过现场调研将工况分为三个典型工况,再将系统在三个不同工况的稳定工作点把得到的非线性模型线性化,构成多个模型,用此逼近集气管压力的非线性过程。其次,在已经展开的不同工况稳定工作点模型的基础上,针对多个模型采用基于状态空间模型的广义预测控制方法对进行广义预测控制器的设计,并应用重构步限矩阵的方法作为切换策略,实现了多模型之间的切换。最后,利用MATLAB软件,建立了焦炉集气管压力系统及其控制系统的仿真模型,对所研究的多模型预测控制进行仿真,并与单模型预测控制进行对比分析,分析结果表明多模型预测控制较单模型预测控制平稳且波动较小；在加入阶跃扰动后的对比曲线表明了多模型预测控制较单模型预测控制有抗扰性,系统在短时间内可调整回目标压力值；在系统受到未知随机干扰的情况下,多模型预测控制方法使集气管压力输出值在目标压力值附近波动且较单模型预测控制方法偏差较小。综上仿真结果表明,本文采用的方法可使处不同工况的集气管压力较单模型预测方法得到良好的控制,并具有一定抗扰性,验证了此方法的有效性。更多还原

【Abstract】 Coke is the main raw material in the etallurgical industry. In the coking process, large amount of by-product gas will be generated from coke ovens, and the process of recycling by-product gas is called gas collecting process. It is an important link in the iron and steel production, which not only saves energy but also reduces environmental pollution.The stability of gas-collectors’ pressure directly affects the gas quality, the life-time of ovens and the producing environment. Therefore, it is a vital significance for the iron and steel enterprise to study on the control of gas collecting process of multi-asymmetrical coke ovens.The gas collecting process of multi-asymmetrical coke ovens is a highly complex industrial process. Its characteristics of multivariable, strong coupling, asymmetry and nonlinearity, time-varying and hard in modeling are the major difficulties in the control of gas collecting process, so it is hard to achieve effective control using traditional control methods. Comprehensive consideration on the physical features and technological characteristics of coke oven gas-collector pressure system, this paper has mainly studied the mechanism modeling method and multi-model predictive control method used in the gas-collector pressure control.Firstly, with comprehensive consideration on the physical features and technological, this paper builds the mechanism model. Through the field research this paper divides the working conditions into three typical working conditions and linearizes the nonlinear model with different stable operating points, with these linear models approaching to the gas-collector nonliear process.Secondly, on the basis of models expanded in different stable working points, this paper designs predictive controllers with three models and uses a method of rebuilding the matrix of GPC algorithm as the switching strategy so as to make sure of the system switching smoothly.Finally, with the help of MATLAB this paper makes the simulation of the multi-model predictive control method and compares it with the single-model predictive control. Simuliation results demonstrate that the method used in this paper can adapt different working conditions well without the fluctuation at the switching time; with the step disturbance the simuliation shows the advantage of adapting of the method used in this paper and what’s more it also has some certain immunity, system can easily adapt to the taget pressure value; with the random perturbance, method used in this paper also shows pressure smaller deviation. All of the above results have verified the control strategy of this paper.更多还原