I 摘摘 要要 目前，电液比例控制技术不断发展，电液比例控制技术己在液压控制中占有重要地位。同时，随着比例元器件的发展和计算机技术的广泛应用，比例阀性能不断的提高，比例阀在很多方面性能与伺服阀相当，目前在工业控制领域得到了广泛应用。电液比例控制系统是基于比例控制技术上的液压控制系统，其应用已经相当普遍，在新系统设计和旧设备的改造中正成为用户的重要选择方案，对提高企业的技术装备水平和设备的自动化程度发挥了极为重要的作用。 本文以摩擦焊机作为研究对象，类比电液伺服系统的设计方法，并利用仿真手段设计和分析摩擦焊机的电液比例双闭环控制系统。 本文研究了电液比例溢流阀及电液比例控制系统的动态数学模型，分析了系统的物理意义，建立了简化的数学模型。并且分析了摩擦焊机的比例施力系统响应及滑台速度响应过程。根据摩擦焊机的实际工作要求及相关产品样本，做出有关参数估计，逐步分析了系统及电液比例阀各个环节的动态性能。最后使用 Matlab/Simulink 仿真软件进行仿真分析，对比分析了摩擦焊机单闭环液压控系统及双闭环液压控制系统。本文是一种基于实际工作基础上的电液比例控制系统理论应用的研究， 还需在实际生产中进行修改和完善。 关键词：关键词：摩擦焊； 双闭环； 电液比例控制； 仿真分析 II Abstract Nowadays, with the development of electro hydraulic proportional control technology, it has been playing an important role in the field of hydraulic control. Meanwhile with the improvement of proportional valves property, it is possible that proportional valve gives way to servo valve in widely application in the future. Electro hydraulic proportional control system is a hydraulic control system base on technology of proportional control. In this paper, I take the friction welding machine as researching object, imitate a design method of servo system and apply to the method of emulation mode to analyze double closed- loop control system of friction welding machine base on anticipating mechanical design of the machine. In this paper, the dynamic mathematical model of electro hydraulic proportional relief valve and the control functions of hydraulic system has been studied, the physical meaning of the system has been analyzed, the simplified mathematical model has established.And the ratio of electro hydraulic proportional force control system response and speed response to the process of sliding has been analyzed. According with the actual job requirements and related product sample of friction welding machine, the relative parameter on the ground of demand of the line and style book of proportional valve has been estimated.The dynamical property of a several links have been analyzed step by step. Finally, the Matlab/Simulink simulation software has been used for the simulation analysis, the single closed-loop and dual-closed-loop hydraulic control system of the friction welding has been analyzed comparatively. However, the design result of the method is a exploring of theory which certifying and rectifying by the accomplishment of the actual production. Keywords： Friction welding； Double feedback control； Electrohydraulic proportional control system； Simulated analysis III 目 录 摘 要. I Abstract . II 1 绪 论. 1 1.1 课题背景. 1 1.2 国内外相关研究现状和发展趋势. 2 1.2.1 摩擦焊机的发展概况. 2 1.2.2 电液比例控制技术的发展概况. 3 1.3 研究的内容、目的和意义. 5 1.3.1 研究的内容. 5 1.3.2 研究的目的及意义. 5 2 课题研究的主要技术基础. 7 2.1 电液比例控制技术. 7 2.1.1 电液控制系统的组成. 7 2.1.2 电液比例控制技术. 8 2.1.3 电液比例控制系统的工作原理及组成. 9 2.1.4 电液比例控制系统的分类. 11 2.1.5 电液比例控制系统的特点. 12 2 课题研究的技术基础. 14 2.2 电液比例控制的基础知识. 14 2.2.1 经典控制理论在系统分析中的应用. 14 2.2.2 微分方程及数学模型的线性化. 15 2.2.3 传递函数. 15 2.2.4 方块图及其等效变换. 16 2.2.5 控制系统时域性能指标. 16 2.2.6 控制系统的频率特性. 17 2.3 MATLAB 在液压控制系统仿真中的应用 .