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基于单片机的电冰箱温控系统设计【自动化毕业论文开题报告外文翻译说明书】.zip,自动化毕业论文开题报告外文翻译说明书,系统的设计【说明书论文开题报告外文翻译】,基于单片机的,系统【说明书论文开题报告外文翻译】,系统开题报告,自动化系统设计,毕业设计论文,自动化毕业论文

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毕 业 设 计（论 文）任 务 书1本毕业设计（论文）课题应达到的目的： 通过毕业设计，使学生受到电气工程师所必备的综合训练，在不同程度上提高各种设计及应用能力，具体包括以下几方面：1. 调查研究、中外文献检索与阅读的能力。2. 综合运用专业理论、知识分析解决实际问题的能力。3. 定性与定量相结合的独立研究与论证的能力。4. 设计方案的制定、仪器设备的选用、安装、调试及实验数据的测试、采集与分析处理的能力。5. 设计、计算与绘图的能力，包括使用计算机的能力。6. 逻辑思维与形象思维相结合的文字及口头表达的能力。7. 撰写设计说明书或论文的能力。2本毕业设计（论文）课题任务的内容和要求（包括原始数据、技术要求、工作要求等）： 1.本设计应完成将单片机技术引入冰箱控制系统的设计之中，要求实现如下控制：1) 多点检测每一个箱门的温度传感器必需达到2个，只要有一个达到一定的温度就直接进行下一步的控制。2）用功能键进行各种温度的设定。3）具有延迟启动功能4）自动除霜5）冰箱门处于半开状态时间过长，和开一点点的状态时间过长时进行不一样的警报。6）当欠压和过压是禁止启动压缩机，且具有警报声。2按时完成开题报告书。3按时完成毕业设计外文参考资料。4能够圆满完成指导老师布置的课题任务，设计方案合理，能够体现一定的创新性。5按时参加答辩，在答辩前各项规定的资料要齐全。毕 业 设 计（论 文）任 务 书3对本毕业设计（论文）课题成果的要求包括图表、实物等硬件要求： 1.按期完成一篇符合金陵科技学院论文规范的毕业设计说明书（毕业论文），能详细说明设计步骤和思路；2.能有结构完整，合理可靠的技术方案；3.能有相应的电气部分硬件电路设计说明；4.有相应的图纸和技术参数说明。5.有相应的软件程序流程图，并给出调试成功后的结论。4主要参考文献： 1唐德里,王香.单片机学习机及编程器的设计与制作J.现代电子,2005(12):117-1202求是科技.8051系列单片机C程序设计完全手册M.北京:人民邮电出版社,20063张鑫等.单片机原理及应用M.北京:电子工业出版社,20064谭浩强.C程序设计(第三版)M.北京:清华大学出版社,20055周兴华.单片机智能化产品C语言设计实例详解M.北京:北京航空航天大学出版社,20076张齐等.单片机应用系统设计技术基本C语言编程M.北京:电子工业出版社,20047王东锋,董冠强.单片机C语言应用100例M.北京:电子工业出版社,20098余瑾,姚燕.基于DS18B20测温的单片机温度控制系统J.单片机开发与应用,2009,25（3-2）:105-106.9林益平.基于SST89E54RD单片机的MONITOR-51仿真器设计J.肇庆学院学报,2008,29(2):29-32.10徐玮.经济型51仿真器-电子制作J.电子制作,2004(8):30-32.11梁凯淋.单片机技术的发展及应用J.中小企业管理与科技:下旬刊,2009(4):247.12沙占友.单片机外围电路设计M.电子工业出版社, 2003.13凌玉华.单片机原理及应用系统设计M.长沙:中南大学出版社,2006.14张齐,朱宁西.单片机系统设计与开发:基于Pro-tens单片机仿真和C语言编程M.北京:机械工业出版社,2008.15廖琪梅,韩彬,杨文昭,等.基于单总线器件DS18B20的温度测量仪J.国外电子元器件, 2008(2):24-26.毕 业 设 计（论 文）任 务 书5本毕业设计（论文）课题工作进度计划：2015.11.1012.1312.1512.312016.01.0904.0504.0604.1004.1105.1005.1405.1505.1605.2905.3006.0706.0706.30调研、收集相关资料、对学生进行初步辅导，拟题、选题、填写任务书。与指导教师共同确定毕业设计课题学生查看任务书，为毕业设计的顺利完成，进行前期准备。12月31日前正式下发任务书。学生在指导教师的具体指导下进行毕业设计创作；拟定论文提纲或设计说明书（下称文档）提纲；撰写及提交开题报告、外文参考资料及译文、论文大纲； 在2016年4月5日前学生要提交基本完成的毕业设计创作成果以及文档的撰写提纲，作为中期检查的依据。指导教师指导、审阅，定稿由指导教师给出评语，对论文主要工作未通过的学生下发整改通知。提交中期课题完成情况报告给指导教师审阅；各专业组织中期检查（含毕业设计成果验收检查）。进行毕业设计文档撰写；2016年5月8日为学生毕业设计文档定稿截止日。2016年5月9日-13日，指导教师和评阅教师通过毕业设计（论文）管理系统对学生的毕业设计以及文档进行评阅，包括打分和评语。5月1日前，做好答辩安排，通知学生回校进行答辨查看答辩安排，毕业设计（论文）小组答辩对未通过答辨的学生进行二次答辨完成毕业设计的成绩录入根据答辩情况修改毕业设计（论文）的相关材料，并在毕业设计（论文）管理系统中上传最终稿，并且上交纸质稿。2016年6月7日为学生毕业设计文档最终稿提交截止日。各系提交本届毕业设计（论文）的工作书面总结及相关材料。所在专业审查意见：通过负责人： 2015 年 12 月21 日 毕 业 设 计（论文） 开 题 报 告 1结合毕业设计（论文）课题情况，根据所查阅的文献资料，每人撰写不少于1000字左右的文献综述： 温度是日常生活,工业,医学,环境保护,化工,石油等领域最常遇到的一个物理量.随着现代工业和农业的发展,人们需要对生产中的温度进行比较精确的控制.而人工进行温度控制的精度较低,这就需要利用单片机的温度控制系统.这个控制系统大大提高了控制精度,不但控制简捷,而且还能和计算机通信,大大提高了生产效率。一、单片机控制基本概念所谓单片机，是指把组成微型计算机的各个功能部件（中央处理器CPU、随机存储器RAM、只读存储器ROM、输入/输出接口电路、定时器/计数器以及串行通信接口等）集成在一块芯片中构成的一个完整的微型计算机。因此单片机早期的含义为单片微型计算机（Single Chip Microcomputer），中文直译为单片机，并一直沿用至今。 由于单片机面对的是测控对象，突出的是控制功能，所以它从功能和形态上来说都是应控制领域应用的要求而诞生的。随着单片机技术的发展，人们可以在芯片内集成许多面对测控对象的接口电路，如ADC、DAC、高速I/O口、PWM和WDT等。这些对外电路及外设接口已经突破了微型计算机（Microcomputer）传统的体系结构，所以，更能确切反映单片机本质的叫法应是微控制器MCU（Micro Controller Unit）。 单片机是以单芯片形态进行嵌入式应用的计算机，它有唯一的专门为嵌入式应用而设计的体系结构和指令系统，加上它的芯片级体积的优点和在现场环境下可高速可靠地运行的特点，因此单片机又称为嵌入式微控制器（Embedded Micro controller）。 基于单片机对工业生产中温度的控制与设计，包括硬件组成和软件的设计，该系统在硬件设计上主要是通过温度传感器对温度进行采集，把温度转换成变化的电压，然后由放大器将信号放大，通过 A/D 转换器，将模拟温度电压信号转化为对应的数字温度信号电压。其硬件设计中最为核心的器件是单片机89C51，它一方面控制 A/D 转换器实现模拟信号到数字信号的转换，另一方面，将采集到的数字温度电压值经计算机处理得到相应的温度值，送到 LED 显示器，以数字形式显示测量的温度。整个系统的软件编程就是通过汇编语言对单片机 MT89C51 实现其控制功能。整个系统结构紧凑，简单可靠，操作灵活，功能强大，性能价格比高，较好的满足了现代生产和科研的需要二、单片机的发展趋势单片机诞生于20世纪70年代末，经历了SCM、MCU、SoC三大阶段。单片机是嵌入式系统的独立发展之路，向MCU阶段发展的重要因素，就是寻求应用系统在芯片上的最大化解决；因此，专用单片机的发展自然形成了SoC化趋势。随着微电子技术、IC设计、EDA工具的发展，基于SoC的单片机应用系统设计有较大的发展。因此，对单片机的理解可以从单片微型计算机、单片微控制器延伸到单片应用系统。目前单片机渗透到我们生活的各个领域，几乎很难找到哪个领域没有单片机的踪迹。导弹的导航装置，飞机上各种仪表的控制，计算机的网络通讯与数据传输，工业自动化过程的实时控制和数据处理，广泛使用的各种智能IC卡，民用豪华轿车的安全保障系统，录象机、摄象机，以及程控玩具等等，这些都离不开单片机。 单片机的技术进步反映在内部结构、功率消耗、外部电压等级以及制造工艺上。在这几方面，较为典型地说明了数字单片机的水平。在目前，用户对单片机的需要越来越多，但是，要求也越来越高。在单片机应用中，可靠性是首要因素为了扩大单片机的应用范围和领域，提高单片机自身的可靠性是一种有效方法。近年来，单片机的生产厂家在单片机设计上采用了各种提高可靠性的新技术：EFT（Ellectrical Fast Transient）技术，低噪声布线技术及驱动技术，采用低频时钟。同时单片机在目前的发展形势下还表现出可靠性及应用越来越水平高和互联网连接，所集成的部件越来越多，功耗越来越低和模拟电路结合越来越多等发展趋势。三、基于单片机的冰箱温控采用温度传感器测得冷冻室温度，通过单线与单片机通信，单片机将此温度值进行保存后，通过控制版面的按键输入某一冷冻室温度设定值，这个设定的温度值由单片机送往右边四位数码。显示的同时，还不断与实测的冷冻室温度进行比较，来控制压缩机的运转状态和电冰箱制冷过程。压缩机运行后，冷冻室温度不断下降，控温程序将对冷冻室温度是否比设定的温度低继续进行比较来控制压缩机停机或保持压缩机开机状态不变。系统软件采用模块化程序设计思想，用C语言编制。控制程序主要有三部分:主程序、定时器T0中断服务程序和定时器T1中断服务程序。还有一些LED数码管显示程序、A/D转换程序、温度传感器程序设计的子程序。主程序是整个电冰箱的总控制程序，如控制各单元初始化、控制中断、定时、显示，键盘程序的启动与重复等。本文主要用的文献： 1 杨前利. 基于数字PID的闭环温度控制系统的设计J. 计算机与数字工程. 2013(12) 2 卢菡涵,刘志奇,徐昌贵,侯云辉,刘振俊. 半导体制冷技术及应用J. 机械工程与自动化. 2013(04) 3 刘谈平,王召巴,刘伟奇. 综合采用PWM和PID反馈技术的LD电源J. 北京理工大学学报. 2013(03) 4 王超,唐浩,黄林. 基于Pt100型铂热电阻的温度测量和控制系统J. 仪表技术. 2013(02) 5 谢军,刘清惓. 基于MEMS和数字信号处理器的露点传感器设计J. 制造业自动化. 2013(03) 6 李德贵,李思琦. 基于C8051F350及CC1000的高精度无线水温测量系统设计J. 电子产品世界. 2013(01) 7 李春霞,沈燕妮,宿忠娥. 家用电暖气温控器的设计J. 工业仪表与自动化装置. 2012(01) 8 HN,海林. “绿动”温控器J. 设计. 2012(05) 9 刘洋,陈志平,张巨勇,童静. 反射炉智能温控系统的研究与展望J. 工业控制计算机. 2012(10 10 蓝伟铭,李杨. 某饲养基地自动化温控系统改造J. 民营科技. 2011(09) 11 何超,吴晗平,胡大军,张焱. 太阳能光伏/光热综合利用的温控系统设计J. 光电技术应用. 2009(06) 12 曹伟,陈新蕾. 基于无线网络的楼宇温控系统的研究J. 哈尔滨理工大学学报. 2008(02) 13 李全利主编.可编程序控制器及其网络系统的综合应用技术M. 机械工业出版社, 2005 14 谢玲,汤广发. 半导体制冷技术的发展与应用J. 洁净与空调技术. 2008(01) 15 路平,薛树琦. Modbus协议下单片机与eView触摸屏的通信方法J. 单片机与嵌入式系统应用. 2007(04) 16 杨再生. 单片机温度监控系统简介J. 聚酯工业. 2006(03)毕 业 设 计（论文） 开 题 报 告 2本课题要研究或解决的问题和拟采用的研究手段（途径）： 本课题要研究或解决的问题是：1.如何对系统的硬件设备进行选择，如何对硬件电路进行研究规划；2.在一定的基础上，如何进行软件编程；3.在完成上述两个步骤后，还需考虑怎样设计出整体的电路原理图。研究手段（途径）：1.去图书馆查阅相关资料，经过汇总，作为参考资料；2.充分利用网络资源，进行相关信息的搜索；3.以小组讨论的形式展开对课题的研究；4.理论联系实际，利用学校创新实验室中的设备进行模拟仿真。毕 业 设 计（论文） 开 题 报 告 指导教师意见：1对“文献综述”的评语：该生通过大量搜集和查阅文献资料，对所设计系统的应用背景及相关的国内外研究情况进行了较好地综合分析和归纳整理，确立了论文研究方向、研究方法及研究内容。能利用文献内容形成自己的观点，内容充实。2对本课题的深度、广度及工作量的意见和对设计（论文）结果的预测：该生思路清晰，课题深度、广度适中，工作量大小适中，按照毕业设计进度安排能在规定时间内完成毕业论文。 3.是否同意开题： 同意 不同意 指导教师： 2016 年 03 月 28 日所在专业审查意见：同意 负责人： 2016 年 03 月 28 日Temperature Control Using a Microcontroller:An Interdisciplinary Undergraduate Engineering Design ProjectJames S. McDonaldDepartment of Engineering ScienceTrinity UniversitySan Antonio, TX 78212AbstractThis paper describes an interdisciplinary design project which was done under the authors supervision by a group of four senior students in the Department of Engineering Science at Trinity University. The objective of the project was to develop a temperature control system for an air-filled chamber. The system was to allow entry of a desired chamber temperature in a prescribed range and to exhibit overshoot and steady-state temperature error of less than 1 degree Kelvin in the actual chamber temperature step response. The details of the design developed by this group of students, based on a Motorola MC68HC05 family microcontroller, are described. The pedagogical value of the problem is also discussed through a description of some of the key steps in the design process. It is shown that the solution requires broad knowledge drawn from several engineering disciplines including electrical, mechanical, and control systems engineering.1 IntroductionThe design project which is the subject of this paper originated from a real-world application. A prototype of a microscope slide dryer had been developed around an OmegaTM model CN-390 temperature controller, and the objective was to develop a custom temperature control system to replace the Omega system. The motivation was that a custom controller targeted specifically for the application should be able to achieve the same functionality at a much lower cost, as the Omega system is unnecessarily versatile and equipped to handle a wide variety of applications.The mechanical layout of the slide dryer prototype is shown in Figure 1. The main element of the dryer is a large, insulated, air-filled chamber in which microscope slides, each with a tissue sample encased in paraffin, can be set on caddies. In order that the paraffin maintain the proper consistency, the temperature in the slide chamber must be maintained at a desired (constant) temperature. A second chamber (the electronics enclosure) houses a resistive heater and the temperature controller, and a fan mounted on the end of the dryer blows air across the heater, carrying heat into the slide chamber. This design project was carried out during academic year 199697 by four students under the authors supervision as a Senior Design project in the Department of Engineering Science at Trinity University. The purpose of this paper isto describe the problem and the students solution in some detail, and to discuss some of the pedagogical opportunities offered by an interdisciplinary design project of this type. The students own report was presented at the 1997 National Conference on Undergraduate Research 1. Section 2 gives a more detailed statement of the problem, including performance specifications, and Section 3 describes the students design. Section 4 makes up the bulk of the paper, and discusses in some detail several aspects of the design process which offer unique pedagogical opportunities. Finally, Section 5 offers some conclusions.2 Problem StatementThe basic idea of the project is to replace the relevant parts of the functionality of an Omega CN-390 temperature controller using a custom-designed system. The application dictates that temperature settings are usually kept constant for long periods of time, but its nonetheless important that step changes be tracked in a “reasonable” manner. Thus the main requirements boil down toallowing a chamber temperature set-point to be entered,displaying both set-point and actual temperatures, andtracking step changes in set-point temperature with acceptable rise time, steady-state error, and overshoot.Although not explicitly a part of the specifications in Table 1, it was clear that the customer desired digital displays of set-point and actual temperatures, and that set-point temperature entry should be digital as well (as opposed to, say, through a potentiometer setting).3 System DesignThe requirements for digital temperature displays and setpoint entry alone are enough to dictate that a microcontrollerbased design is likely the most appropriate. Figure 2 shows a block diagram of the students design. The microcontroller, a MotorolaMC68HC705B16 (6805 for short), is the heart of the system. It accepts inputs from a simple four-key keypad which allow specification of the set-point temperature, and it displays both set-point and measured chamber temperatures using two-digit seven-segment LED displays controlled by a display driver. All these inputs and outputs are accommodated by parallel ports on the 6805. Chamber temperature is sensed using a pre-calibrated thermistor and input via one of the 6805s analog-to-digital inputs. Finally, a pulse-width modulation (PWM) output on the 6805 is used to drive a relay which switches line power to the resistive heater off and on.Figure 3 shows a more detailed schematic of the electronics and their interfacing to the 6805. The keypad, a Storm 3K041103, has four keys which are interfaced to pins PA0 PA3 of Port A, configured as inputs. One key functions as a mode switch. Two modes are supported: set mode and run mode. In set mode two of the other keys are used to specify the set-point temperature: one increments it and one decrements. The fourth key is unused at present. The LED displays are driven by a Harris Semiconductor ICM7212 display driver interfaced to pins PB0PB6 of Port B, configured as outputs. The temperature-sensing thermistor drives, through a voltage divider, pin AN0 (one of eight analog inputs). Finally, pin PLMA (one of two PWM outputs) drives the heater relay.Software on the 6805 implements the temperature control algorithm, maintains the temperature displays, and alters the set-point in response to keypad inputs. Because it is not complete at this writing, software will not be discussed in detail in this paper. The control algorithm in particular has not been determined, but it is likely to be a simple proportional controller and certainly not more complex than a PID. Some control design issues will be discussed in Section 4, however.4 The Design ProcessAlthough essentially the project is just to build a thermostat, it presents many nice pedagogical opportunities. The knowledge and experience base of a senior engineering undergraduate are just enough to bring him or her to the brink of a solution to various aspects of the problem. Yet, in each case, realworld considerations complicate the situation significantly.Fortunately these complications are not insurmountable, and the result is a very beneficial design experience. The remainder of this section looks at a few aspects of the problem which present the type of learning opportunity just described. Section 4.1 discusses some of the features of a simplified mathematical model of the thermal properties of the system and how it can be easily validated experimentally. Section 4.2 describes how realistic control algorithm designs can be arrived at using introductory concepts in control design. Section 4.3 points out some important deficiencies of such a simplified modeling/control design process and how they can be overcome through simulation. Finally, Section 4.4 gives an overview of some of the microcontroller-related design issues which arise and learning opportunities offered.4.1 MathematicalModelLumped-element thermal systems are described in almost any introductory linear control systems text, and just this sort of model is applicable to the slide dryer problem. Figure 4 shows a second-order lumped-element thermal model of the slide dryer. The state variables are the temperatures Ta of the air in the box and Tb of the box itself. The inputs to the system are the power output q(t) of the heater and the ambient temperature T. ma and mb are the masses of the air and the box, respectively, and Ca and Cb their specific heats. 1 and 2 are heat transfer coefficients from the air to the box and from the box to the external world, respectively.Its not hard to show that the (linearized) state equationscorresponding to Figure 4 areTaking Laplace transforms of (1) and (2) and solving for Ta(s), which is the output of interest, gives the following open-loop model of the thermal system:where K is a constant and D(s) is a second-order polynomial.K, tz, and the coefficients of D(s) are functions of the variousparameters appearing in (1) and (2).Of course the various parameters in (1) and (2) are completely unknown, but its not hard to show that, regardless of their values, D(s) has two real zeros. Therefore the main transfer function of interest (which is the one from Q(s), since well assume constant ambient temperature) can be writtenMoreover, its not too hard to show that 1=tp1 1=tz 1=tp2, i.e., that the zero lies between the two poles. Both of these are excellent exercises for the student, and the result is the openloop pole-zero diagram of Figure 5.Obtaining a complete thermal model, then, is reduced to identifying the constant K and the three unknown time constants in (3). Four unknown parameters is quite a few, but simple experiments show that 1=tp1 _ 1=tz;1=tp2 so that tz;tp2 _ 0 are good approximations. Thus the open-loop system is essentially first-order and can therefore be written (where the subscript p1 has been dropped).Simple open-loop step response experiments show that,for a wide range of initial temperatures and heat inputs, K _0:14 _=W and t _ 295 s.14.2 Control System DesignUsing the first-order model of (4) for the open-loop transfer function Gaq(s) and assuming for the moment that linear control of the heater power output q(t) is possible, the block diagram of Figure 6 represents the closed-loop system. Td(s) is the desired, or set-point, temperature,C(s) is the compensator transfer function, and Q(s) is the heater output in watts.Given this simple situation, introductory linear control design tools such as the root locus method can be used to arrive at a C(s) which meets the step response requirements on rise time, steady-state error, and overshoot specified in Table 1. The upshot, of course, is that a proportional controller with sufficient gain can meet all specifications. Overshoot is impossible, and increasing gains decreases both steady-state error and rise time.Unfortunately, sufficient gain to meet the specifications may require larger heat outputs than the heater is capable of producing. This was indeed the case for this system, and the result is that the rise time specification cannot be met. It is quite revealing to the student how useful such an oversimplified model, carefully arrived at, can be in determining overall performance limitations.4.3 Simulation ModelGross performance and its limitations can be determined using the simplified model of Figure 6, but there are a number of other aspects of the closed-loop system whose effects on performance are not so simply modeled. Chief among these arequantization error in analog-to-digital conversion of the measured temperature and the use of PWM to control the heater.Both of these are nonlinear and time-varying effects, and the only practical way to study them is through simulation (or experiment, of course).Figure 7 shows a SimulinkTM block diagram of the closed-loop system which incorporates these effects. A/D converter quantization and saturation are modeled using standard Simulink quantizer and saturation blocks. Modeling PWM is more complicated and requires a custom S-function to represent it.This simulation model has proven particularly useful in gauging the effects of varying the basic PWM parameters and hence selecting them appropriately. (I.e., the longer the period, the larger the temperature error PWM introduces. On the other hand, a long period is desirable to avoid excessive relay “chatter,” among other things.) PWM is often difficult for students to grasp, and the simulation model allows an exploration of its operation and effects which is quite revealing.4.4 The MicrocontrollerSimple closed-loop control, keypad reading, and display control are some of the classic applications of microcontrollers, and this project incorporates all three. It is therefore an excellent all-around exercise in microcontroller applications. In addition, because the project is to produce an actual packaged prototype, it wont do to use a simple evaluation board with the I/O pins jumpered to the target system. Instead, its necessary to develop a complete embedded application. This entails the choice of an appropriate part from the broad range offered in a typical microcontroller family and learning to use a fairly sophisticated development environment. Finally, a custom printed-circuit board for the microcontroller and peripherals must be designed and fabricated.Microcontroller Selection. In view of existing local expertise, the Motorola line of microcontrollers was chosen for this project. Still, this does not narrow the choice down much. A fairly disciplined study of system requirements is necessary to specify which microcontroller, out of scores of variants, is required for the job. This is difficult for students, as they generally lack the experience and intuition needed as well as the perseverance to wade through manufacturers selection guides.Part of the problem is in choosing methods for interfacing the various peripherals (e.g., what kind of display driver should be used?). A study of relevant Motorola application notes 2, 3, 4 proved very helpful in understandingwhat basic approaches are available, and what microcontroller/peripheral combinations should be considered.The MC68HC705B16 was finally chosen on the basis of its availableA/D inputs and PWMoutputs as well as 24 digital I/O lines. In retrospect this is probably overkill, as only one A/D channel, one PWM channel, and 11 I/O pins are actually required (see Figure 3). The decision was made to err on the safe side because a complete development system specific to the chosen part was necessary, and the project budget did not permit a second such system to be purchased should the firstprove inadequate.Microcontroller Application Development. Breadboarding of the peripheral hardware, development of microcontroller software, and final debugging and testing of a custom printed-circuit board for the microcontroller and peripherals all require a development environment of some kind. The choice of a development environment, like that of the microcontroller itself, can be bewildering and requires some faculty expertise. Motorola makes three grades of development environment ranging from simple evaluation boards (at around $100) to full-blown real-time in-circuit emulators (at more like $7500). The middle option was chosen for this project: the MMEVS, which consists of _ a platform board (which supports all 6805-family parts), _ an emulator module (specific to B-series parts), and _ a cable and target head adapter (package-specific). Overall, the system costs about $900 and provides, with some limitations, in-circuit emulation capability. It also comes with the simple but sufficient software development environment RAPID 5.Students find learning to use this type of system challenging, but the experience they gain in real-world microcontroller application development greatly exceeds the typical first-course experience using simple evaluation boards.Printed-Circuit Board. The layout of a simple (though definitely not trivial) printed-circuit board is another practical learning opportunity presented by this project. The final board layout, with package outlines, is shown (at 50% of actual size) in Figure 8. The relative simplicity of the circuit makes manual placement and routing practicalin fact, it likely gives better results than automatic in an application like thisand the student is therefore exposed to fundamental issues of printed-circuit layout and basic design rules. The layout software used was the very nice package pcb,2 and the board was fabricated in-house with the aid of our staff electronics technician.5 ConclusionThe aim of this paper has been to describe an interdisciplinary, undergraduate engineering design project: a microcontroller- based temperature control system with digital set-point entry and set-point/actual temperature display. A particular design of such a system has been described, and a number of design issues which arisefrom a variety of engineering disciplineshave been discussed. Resolution of these issues generally requires knowledge beyond that acquired in introductory courses, but realistically accessible to advance undergraduate students, especially with the advice and supervision of faculty.Desirable features of the problem, from a pedagogical viewpoint, include the use of a microcontroller with simple peripherals, the opportunity to usefully apply introductorylevel modeling of physical systems and design of closed-loop controls, and the need for relatively simple experimentation (for model validation) and simulation (for detailed performance prediction). Also desirable are some of the technologyrelated aspects of the problem including practical use of resistive heaters and temperature sensors (requiring knowledge of PWM and calibration techniques, respectively), microcontroller selection and use of development systems, and printedcircuit design.AcknowledgementsThe author would like to acknowledge the hard work, dedication, and ability shown by the students involved in this project: Mark Langsdorf, Matt Rall, PamRinehart, and David Schuchmann. It is their project, and credit for its success belongs to them.References1 M. Langsdorf, M. Rall, D. Schuchmann, and P. Rinehart,“Temperature control of a microscope slide dryer,” in1997 National Conference on Undergraduate Research,(Austin, TX), April 1997. Poster presentation.2 Motorola, Inc., Phoenix, AZ, Temperature Measurementand Display Using the MC68HC05B4 and the MC14489,1990. Motorola SemiconductorApplicationNote AN431.3 Motorola, Inc., Phoenix, AZ, HC05 MCU LED DriveTechniques Using the MC68HC705J1A, 1995. MotorolaSemiconductor Application Note AN1238.4 Motorola, Inc., Phoenix, AZ, HC05MCU Keypad DecodingTechniques Using the MC68HC705J1A, 1995. MotorolaSemiconductor Application Note AN1239.5 Motorola, Inc., Phoenix, AZ, RAPID Integrated DevelopmentEnvironment Users Manual, 1993. (RAPID wasdeveloped by P & E Microcomputer Systems, Inc.).单片机温度控制：一个跨学科的本科生工程设计项目JamesS.McDonald工程科学系三一大学德克萨斯州圣安东尼奥市78212摘要本文所描述的是作者领导由四个三一大学高年级学生组成的团队进行的一个跨学科工程项目的设计。该项目的目标是设计一个气室内温度控制系统。该系统的要求是：当实际气室的温度阶跃响应时，规定范围内的温度进入气室后，稳定时的温度误差和超调量必须少于一个绝对温度。本组学生开发设计是基于摩托罗拉MC68HC05系列单片机。该问题的教学价值也通过某些步骤的关键描述在本文说明。研究结果表明，解决该方案需要具有广泛的工程学科知识，包括相关电子、机械和控制系统工程的知识。1引言该设计项目来自一个实际应用问题，一个关于显微镜载玻片干燥剂温控器欧米茄CN-390温度控制器，而这个设计的目标是研发一个自定义的通用温度控制系统取代欧米茄系统、一个以更低的成本实现相同功能的自定义控制器，就像欧米茄系统一样，并不需要能够全方位的处理各种问题。该载玻片干燥机的机械布局如图1所示。干燥机的主体是一个足够大的绝缘充气室，里面依次存放着薄纸包着的石蜡。为了使石蜡保持适当稳定性，载玻片气室的温度必须维持稳定。第二个气筒（电子围绕元件）设有一个电阻加热器、一个温度控制器以及一个安装在干燥机上的风扇，是为了把风吹过加热器，把热量带到载玻片气室。图1-1载玻片干燥机的机械布局 自1996-97学年来，本文作者带领四位三一大学工程科学系的高年级学生开展此项目的研究。本文的目的说明了提出一些问题并详细阐述学生的一些解决方案，而且讨论了这种类型的跨学科设计项目在教学方面应用的问题。这份学生报告曾经在1997年全国本科毕业生研讨会上提出过并讨论过。第2节给出该设计的更多详细情况，包括性能规格。第3节具体 学生的设计。第4节是论文的主体，讨论该设计在教学应用方面的实施问题。最后，第5节全文总结。2问题阐述该项目基本的思想是设计一个自定义温度控制系统来取代相关的欧米茄CN-390温度控制器。温度时通常保持在一个稳定的常数，但重要的是阶跃变化可以被“合理”的跟踪。因此主要要求如下：可以对空气室的温度进行设定，同时显示设定值和实际温度，以及在设定温度值情况下，可接受范围内的跟踪阶跃变化，稳态误差，超调量。设定温度接口设定温度显示室内温度显示范围精度准确度60-991C1C室内温度阶梯响应范围（稳定状态）精度（稳定状态）最大超调设定时间（到1）60-991C 1C120s表1精确的规格说明尽管表1部分说明并不明确，但是它清楚的反映了人们对数字显示器在设定值和实际温度的要求和温度应该通过数值输入来设定（而不是，通过电位器设置）。3.系统设计根据微控设计，数字温度显示和单点输入的要求可能是最合适的。图2为学生的设计框图。图3-1温度控制器硬件结构图摩托罗拉MC68HC705B16（简称6805），是系统的核心。它通过一个简单的4键小键盘对温度进行设定，同时使用两个显示驱动控制7段LED数码管来显示定值和气室温度的测量值。所有这些，输入和输出信号与6805的并行口相连。气室的温度值使用预校准热敏电阻测量，并通过6805的数模转换输入。最后，6085的脉冲宽度调制（PWM）输出用来驱动一个继电器，以控制线性电阻加热器的闭合和断开。图3更详细的显示了6805的接口和电子器件。使用暴风3K041103型号四键键盘，通过PA0-PA3端口进行数据输入。其中一个重要的功能是进行模式切换。两种模式：固定模式和运行模式。在固定模式下，其他两个键用于设定温度，一个增加，一个减少，第四个按键暂无作用。LED显示屏由哈里斯半导体ICM7212进行驱动，通过PB0-PB6端口与芯片相连，作为输出。热敏电阻由电压分频器驱动，通过AN0针脚（八个模拟输入端口中的一个）相连。最后，PLMA针脚（两个PWM输出端口中的一个）驱动加热继电器。图3-2 单片机原理图图3单片机原理图是关于用软件实现温度控制算法、保持温度显示以及改变键盘输入响应，这将不会在本文详细讨论，因为这并不是本文的重点，也没有编译完成。软件部分还没有确定控制算法，但很可能是一个简单的比例控制，比PID算法简单。一些控制设计的问题将在第四节讨论。4 设计过程虽然该项目的本质是建立一个恒温器，但它有许多很好的契机可以供教学借鉴。高级工程本科教育的知识只是能够让学生们具有解决问题的能力。然而，很多情况下，实际情况却和理论有些不同。不过，这些不是问题，参与这个项目的设计，将获得很多设计方面的宝贵经验。本节的其余部分着眼于其他的几个方面：4.1节讨论系统的一些特征，简化系统热性能的数学模型，以及一些简单理论的证明。4.2节介绍确定实际控制算法。4.3节指出控制设计程序的一些不足，并通过模拟环境，指出怎样克服问题。4.4节给出单片机的一些设计相关概述，以及出现问题和值得借鉴之处。4.1数学模型集总元件热系统符合线性控制，适用于载玻片干燥机的问题。图4显示了二阶集总元件热量模型的载玻片干燥机。状态变量是温度，Ta是箱内空气的温度，Tb是箱子本身的温度。该系统输入功率等于q(t)的热量和环境温度T的和。ma，mb分别对应空气和箱子的质量。Ca和Cb则分别是其对应热量。m1和m2分别是空气与箱子间以及箱子与外界间的传热系数。图4-1集总元件热模型由图4可以推出（线性）状态方程拉普拉斯变换(1)和(2)等式，并整理T