电大机电一体化系统设计试题与答案.doc

专业好文档题号一二三四五六七八九十总分评分评卷教师一、填空题（每空1分，共20分）1滚珠丝杆中滚珠的循环方式有 、 两种。2机电一体化系统，设计指标和评价标准应包括 、 、 、 3在伺服系统中，在满足系统工作要求的情况下，首先应保证系统的 ，并尽量高伺服系统的响应速度。4.1.2.3.4.5.6.7.8.9.10.11.12.13. 实现步进电动机通电环形分配的三种常用方法是 、 、 。5抑制电磁干扰的常用方法有屏蔽、 、 、 、合理布局和软件抗干扰技术。6机电一体化系统一般由_、_、接口、_、_、_等部分组成。7机电一体化系统（产品）设计类型大致可分为_、适应性设计、_。二、简答题（每题5分，共30分）1、机电一体化系统中的计算机接口电路通常使用光电耦合器，光电耦合器的作用有哪些？2、什么是三相六拍通电方式？3、简述PWM脉宽调速原理。4、简述香农采样定理。5、什么叫传感器？它是由哪几部分组成的？6、步进电动机常用驱动电路中功率放大电路有哪几种类型?三、计算题（共20分）（将本题答案写在答题纸上）（一）、（10分）三相变磁阻式步进电动机，转子齿数Z=100,双拍制通电，要求电动机转速为120r/min，输入脉冲频率为多少?步距角为多少?（二）、(10分) 光栅传感器，刻线数为100线/mm，设细分时测得莫尔条纹数为400，试计算光栅位移是多少毫米？若经四倍细分后，记数脉冲仍为400，则光栅此时的位移是多少？测量分辨率是多少？四、综合分析题（共30分）（一）、分析、说明如图所示计算机控制系统中信号变换与传输的过程、原理。（二）、伺服控制系统一般包括哪几个部分？每部分能实现何种功能？一、填空题（每空1分，共20分）1、内循环、外循环 2、性能指标 系统功能 使用条件 经济效益 3、稳定性4、 1）采用计算机软件分配器 2）小规模集成电路搭接的硬件分配器 3）专用模块分配器 5、隔离 滤波 接地6、机械本体 动力与驱动 执行机构 传感器检测部分 控制及处理部分 7、开发性设计 变参数设计二、简答（每题5分，共30分）1. （1）能保护系统元件不受高共模电压的损害，防止高压对低压信号系统的损坏。（2）泄漏电流低，对于测量放大器的输入端无须提供偏流返回通路。（3）共模抑制比高，能对直流和低频信号(电压或电流)进行准确、安全的测量。2. 如果步进电动机通电循环的各拍中交替出现单、双相通电状态，这种通电方式称为单双相轮流通电方式。如A AB B BCC CA3. 在一个周期T内闭合的时间为，则一个外加的固定直流电压U被按一定的频率开闭的开关S加到电动机的电枢上，电枢上的电压波形将是一列方波信号，其高度为U、宽度为，如右图所示。电枢两端的平均电压为：式中 =/T=Ud/U，(0<<1) 为导通率（或称占空比）。当T不变时，只要改变导通时间，就可以改变电枢两端的平均电压Ud。当从0T改变时，Ud由零连续增大到U。4.采样频率大于2倍的信号频率，才能正确复现原信号。5传感器是一种以一定的精确度把被测量转换为与之有确定对应关系的，便于应用的某种物理量 的测量装置。敏感元件、转换元件、基本电路。6.单电压、双电压、斩波恒流、恒流源三、计算题（共20分）（一）（10分）K=1; M=3, Z=100; =360/1*3*100=1.2º f=600Hz （二）（10分）100：1=400：x=4 mm四细分：400：1=400：x=1mm分辨率：1÷400=2.5(m)四、综合分析题（30分） （一）（15分）采样过程是用采样开关（或采样单元）将模拟信号按一定时间间隔抽样成离散模拟信号的过程。因采样后得到的离散模拟信号本质上还是模拟信号，未数量化，不能直接送入计算机，故还需经数量化，变成数字信号才能被计算机接受和处理。量化过程（简称量化）就是用一组数码（如二进制码）来逼近离散模拟信号的幅值，将其转换成数字信号，由于计算机的数值信号是有限的，因此用数码来逼近模拟信号是近似的处理方法。信号进入计算机后经其处理经D/A转换后输出。D/A转换器是将数字量转换成模拟量的装置。模拟量输出主要由D/A转换器和输出保持器组成。它们的任务是把微机输出的数字量转换成模拟量。多路模拟量输出通道的结构形式，主要取决于输出保持器的结构形式。保持器一般有数字保持方案和模拟保持方案两种。这就决定了模拟量输出通道的两种基本结构形式。（二）（15分）略"If we don't do that it will go on and go on. We have to stop it; we need the courage to do it."His comments came hours after Fifa vice-president Jeffrey Webb - also in London for the FA's celebrations - said he wanted to meet Ivory Coast international Toure to discuss his complaint.CSKA general director Roman Babaev says the matter has been "exaggerated" by the Ivorian and the British media.Blatter, 77, said: "It has been decided by the Fifa congress that it is a nonsense for racism to be dealt with with fines. You can always find money from somebody to pay them."It is a nonsense to have matches played without spectators because it is against the spirit of football and against the visiting team. It is all nonsense."We can do something better to fight racism and discrimination."This is one of the villains we have today in our game. But it is only with harsh sanctions that racism and discrimination can be washed out of football."The (lack of) air up there Watch mCayman Islands-based Webb, the head of Fifa's anti-racism taskforce, is in London for the Football Association's 150th anniversary celebrations and will attend City's Premier League match at Chelsea on Sunday."I am going to be at the match tomorrow and I have asked to meet Yaya Toure," he told BBC Sport."For me it's about how he felt and I would like to speak to him first to find out what his experience was."Uefa has opened disciplinary proceedings against CSKA for the "racist behaviour of their fans" during City's 2-1 win.Michel Platini, president of European football's governing body, has also ordered an immediate investigation into the referee's actions.CSKA said they were "surprised and disappointed" by Toure's complaint. In a statement the Russian side added: "We found no racist insults from fans of CSKA."Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunda.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, he'll be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes it's not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it won't. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).cause there共 5 页 第 5 页