【作者】 刘文豪；

【导师】 王桂棠；

【作者基本信息】 广东工业大学 ， 材料加工工程， 2006， 硕士

【摘要】 热处理是机器零件及工具制造过程中的重要工序之一,对发掘金属材料强度潜力、改善零件的使用性能、提高产品质量、延长寿命等具有极其重要的意义。而工件的渗碳处理是使碳原子渗入钢制工件表层的化学热处理工艺。渗碳后,工件表面含碳量一般高于0.8%,淬火并低温回火后,在提高表面硬度和耐磨性的同时,心部能保持相当高的韧性,可承受冲击载荷,疲劳强度较高。渗碳工艺是一个复杂的系统,加热、保温、渗层深度,碳浓度分布和碳势气氛等的过程控制直接影响其热处理质量和生产效率。为了提高渗碳的质量,必须提高温度和气氛采集和控制的精度。 本文以渗碳过程中温度和气氛等参数的采集和智能控制技术为研究对象,综合应用了嵌入式技术、计算机控制技术、网络技术、模糊PID控制理论等知识。主要从应用嵌入式技术进行温度、气氛参数的采集、渗碳层浓度分布的实时仿真、模糊PID控制算法、参数动态管理和显示等几个关键问题展开研究。 本文应用了相关的理论研究成果,从实际应用的角度出发,对在嵌入式系统实现渗碳过程中工艺参数采集与智能控制的技术难点进行深入分析,主要研究内容及成果包括: 1、温度、碳势的采集控制:分别采用热电偶和氧探头采集温度、气氛信号,经嵌入式计算机内嵌的A/D电路将电压信号转换成数字信号,通过模糊自适应的模糊规则对PID控制参数进行在线调节,实现对温度和气氛的高精度控制。在多炉区系统的温度控制中,以一个区作为主控区,其他区跟踪主控区的测量变化而调节控制。 2、碳浓度分布的实时仿真控制:建立浓度分布的数学模型,采用“追赶法”求解浓度分布,通过最优控制算法对渗碳浓度分布进行控制。 3、开发嵌入式网络热处理控制器:以嵌入式微处理器S3C44B0X为核心构建硬件平台,并移植了嵌入式实时操作系统μC/OS-Ⅱ。控制器具有A/D、D/A、LCD、RS485、以太网、触摸屏、PWM等功能接口。除了实现参数的采集和控制以外,还可以通过触摸屏设置多达20段工艺的工艺曲线,实时采集和仿真的数据更多还原

【Abstract】 Heat treatment is one of the important processes of machine parts and tool making. It is of the utmost importance in exploring the intensity potential of the metal materials, improving the service performance of parts, improving the product quality, and extending the service life of materials. Carburization is the heat treatment process which carbon atoms permeate into the steel work form its surface. After Carburization, the carbon content of the work surface is generally higher than 0.8%. After Quenching and low tempering, it improves the surface hardness and the resistance to wear while the core still maintains a very high resilience to withstand impact loads, and processes higher fatigue strength. Carburization system is so complex that the process control of heating 、 cooling、 heat preservation、 carbon-depth trend and climate of carbon potential has direct impacts on its heat processing quality and production efficiency.This paper synthesizes the embedded technique、 calculator control technique、 network technique, fuzzy PID control theories etc. Temperature and atmosphere parameter collection and intelligent control technique in carburize are its research object. The key researches in this paper are how to apply embedded technique to collect and control the temperature and atmosphere in carburize 、 real-time carbon density distribution emulation、 fuzzy PID algorithm、 parameter management and dynamic display etc.Based on practice, this paper analyses the key techniques of process parameter collection and intelligent control technique in embedded system deeply. The content includes:1. Collection and control of temperature and carbon potential: use thermo-couple and oxygen detector to collect temperature and atmosphere signals which convert voltage signal into digital signal through the embedded A/D circuit and adjust PID parameters through fuzzy self-adapting rules on line.2. Real-time emulation and control of carbon density distribution:establish mathematic module of carbon density distribution, use "Chase Method" to get the density distribution and segment control carburize through optimum control algorithm.3. Develop real-time embedded network controller: The hardware platform is based on embedded S3C44B0X processor. It transplants embedded real-time operation system of /^’Uk-ll , The controller is constituted by function interfaces of A/D,D/A,LCD,RS485, Ethernet touch screen> PWM . We can set process curve as much as 20 sections. The real-time collect date displays on LCD and save in memorizer.4. Establish real-time control network system: establish real-time control system by RS485 field bus provide on the embedded network heat process controller to realize distribute control of the workshop. Centre server processes the function of on line monitoring, it collects and displays field data. We can also save data in the database for the reappear of previous data and to print the report.更多还原