电大机电一体化系统设计基础课程形考作1.doc

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1、专业好文档机电一体化系统设计基础课程形成性考核作业1 答案一、判断题（正确的打，错误的打）1机电一体化系统的主要功能就是对输入的物质按照要求进行处理，输出具有所需特性的物质。（ x ） P42. 系统论、信息论、控制论是机电一体化技术的理论基础，是机电一体化技术的方法论。（ ） P103信息处理技术是指在机电一体化产品工作过程中，与工作过程各种参数和状态以及自动控制有关的信息输入、识别、变换、运算、存储、输出和决策分析等技术。（ ）P114自动控制是在人直接参与的情况下，通过控制器使被控对象或过程自动地按照预定的规律运行。（x ）P115产品的组成零部件和装配精度高，系统的精度一定就高。（x

2、）6为减少机械传动部件的扭矩反馈对电机动态性能的影响，机械传动系统的基本固有频率应低于电气驱动部件的固有频率的23倍，同时，传动系统的固有频率应接近控制系统的工作频率，以免系统产生振荡而失去稳定性。（x ）P217传动机构的转动惯量取决于机构中各部件的质量和转速。（x ）P218在闭环系统中，因齿轮副的啮合间隙而造成的传动死区能使系统以610倍的间隙角产生低频振荡，采用消隙装置，以提高传动精度和系统稳定性。（x ）P449进行机械系统结构设计时，由于阻尼对系统的精度和快速响应性均产生不利的影响，因此机械系统的阻尼比取值越小越好。（x ）P2710滚珠丝杠垂直传动时，必须在系统中附加自锁或制动装

3、置。（ ）P3311采用偏心轴套调整法对齿轮传动的侧隙进行调整，结构简单，且可以自动补偿侧隙。（x ）P4712采用虚拟样机代替物理样机对产品进行创新设计测试和评估，延长了产品开发周期，增加了产品开发成本，但是可以改进产品设计质量，提高面向客户与市场需求能力。（x ）P65二、单选题1 以下产品属于机电一体化产品的是（ C ）。A游标卡尺 B电话C全自动洗衣机 D非指针式电子表2为提高机电一体化机械传动系统的固有频率，应设法（ A ）。 A增大系统刚度 B增大系统转动惯量C增大系统的驱动力矩 D减小系统的摩擦阻力3导程L0=8mm的丝杠驱动总质量为60kg的工作台与工件，则其折算到丝杠上的等效

4、转动惯量为（ B ）kgmm2。 A48.5 B97C4.85 D9.74传动系统的固有频率对传动精度有影响，（ A ）固有频率可减小系统地传动误差，（ A ）系统刚度可提高固有频率。A提高，提高 B提高，减小C减小，提高 D减小，减小5下列哪种方法是采用单螺母预紧原理来消除滚珠丝杠副的间隙？（ D ） A螺纹调隙式 B双螺母垫片调隙式C齿差调隙式 D偏置导程法6. 齿轮传动的总等效惯量随传动级数( B )。 A.增加而减小 B.增加而增加C.减小而减小 D.变化而不变7多级齿轮传动中，各级传动比“前小后大”的分配原则不适用于按（ D ）设计的传动链。 A最小等效转动惯量原则（小功率传动装置）

5、B最小等效转动惯量原则（大功率传动装置）C输出轴的转角误差最小原则D重量最轻原则8某机电一体化系统需要消除齿轮传动的齿侧间隙，采取下列哪种方法使得调整过程中能自动补偿齿侧间隙？（ D ） A偏心套调整法 B轴向垫片调整法C薄片错齿调整法 D轴向压簧错齿调整法三、简答题1完善的机电一体化系统主要包括哪几部分？答：机电一体化系统的基本结构要素有机械本体，动力系统（能源，驱动部分），执行机构，控制及信息处理单元，传感检测部分等5项，各环节和要素之间通过接口相联系。2简述机电一体化系统中的接口的作用。答：机电一体化系统是机械、电子和信息等性能各异的技术融为一体的综合系统，其各要素及各子系统之间的连接与

6、信息传输都要通过接口。从系统外部看，输入/输出是系统与人、环境或其他系统之间的接口；从系统内部看，机电一体化系统是通过许多接口将各组成要素的输入/输出联系成一体的系统。各要素及各子系统之间的接口性能好坏决定了整个机电一体化系统的综合性能。3机械运动中的摩擦和阻尼会降低效率，但是设计中要适当选择其参数，而不是越小越好。为什么？答：一般情况下，摩擦阻尼都发生在运动副的构件之间。系统的静摩擦阻尼大，会使系统的回程误差增大，定位精度降低。系统的黏性阻尼摩擦越大，系统的稳态误差就越大，精度降低。系统的黏性阻尼摩擦会对系统的快速响应性产生不利影响。所以摩擦阻尼不易过大，但是阻尼比除了与机械系统的黏性阻尼系

7、数B有关外，还与系统的刚度和质量有关。如果机械系统刚度低而质量大，则系统的固有频率较低，此时应增大系统的黏性摩擦阻尼，以减小振幅和衰减振动。因此，在进行机械结构设计时，应当通过对刚度、质量和摩擦系数等参数的合理匹配，得到机械系统阻尼比的适当取值，以保证系统的良好动态特性。4简述机械系统的刚度对系统动态特性的影响。答：（1）失动量 系统刚度越大，因静摩擦力作用所产生的传动部件的弹性变形越小，系统的失动量也越小。 （2）固有频率 机械系统刚度越大，固有频率越高，可远离控制系统或驱动系统的频带宽度，从而避免产生共振。 （3）稳定性 刚度对闭环系统的稳定性有很大影响，提高刚度可增加闭环系统的稳定性。四

8、、计算题1.某工作台采用直流电机丝杠螺母机构驱动如图所示，已知电机轴的转动惯量Jm=410-4kgm3，与电机输出轴相连的小齿轮的转动惯量J1=110-4kgm3，大齿轮的转动惯量J2=1.810-4kgm3，丝杠的转动惯量Js=3.810-4kgm3。工作台的质量m=50kg，丝杠导程t=5mm，齿轮减速比为i=5。试求：（1）工作台折算到丝杠的等效转动惯量JG；（2）传动件折算到电机轴的等效转动惯量Je；（3）电机轴上的总转动惯量J。工作台丝杠 滚珠螺母齿轮减速器联轴器DC伺服电机i=5图 直流电机丝杠螺母机构驱动工作台解答：1）工作台折算到丝杠上的等效转动惯量：2）传动件折算到电机轴的等

9、效转动惯量Je； 3）电机轴上的总转动惯量J。2.已知某四级齿轮传动系统，各齿轮的转角误差为1=2=8=0.01弧度，各级减速比相同，即i1 = i2 = i4 =3，求该系统的最大转角误差max。解答： 五、综合题1. 分析下图调整齿侧间隙的原理。1. 锁紧螺母 2. 圆螺母 3. 带凸缘螺母 4.无凸缘螺母解答：这是采用双螺母预紧螺纹调隙来调整齿侧间隙的。原理是1）采用一个外端有凸缘的螺母3，和一个外端无凸缘但制有螺纹的螺母4，螺母4伸出套筒外用两个螺母（1和2）固定锁紧，并用键来防止两螺母相对转动。2）旋转圆螺母2，如果圆螺母2带动丝杠向左微移，则通过外侧的套筒使螺母3向右移动，从而调整

10、、消除间隙，并产生了预紧力，之后再用锁紧螺母锁紧。2.分析下图中传动大负载时消除齿侧间隙的原理。1、6小齿轮 2、5大齿轮 3齿轮 4预载装置 7齿条解答：这是采用双齿轮调整齿侧间隙的。原理是1）小齿轮1、6分别与齿条7啮合。2）小齿轮1、6分别与大齿轮2、5同轴，大齿轮2、5同时与齿轮3啮合。3）通过预载装置4向齿轮3上预加负载，使大齿轮2、5同时向两个相反方向转动，从而带动小齿轮1、6转动，其齿面便分别紧贴在齿条7上齿槽的左、右侧，从而消除了齿侧间隙。If we dont do that it will go on and go on. We have to stop it; we nee

11、d the courage to do it.His comments came hours after Fifa vice-president Jeffrey Webb - also in London for the FAs 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

12、 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

13、 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 mCayma

14、n Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys 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 m

15、e its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered an immedi

16、ate investigation into the referees actions.CSKA said they were surprised and disappointed by Toures 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 Sund

17、a.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)

18、 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)

19、,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

20、too hard. Still, hell 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

21、 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 hop

22、es its 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 wont. 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- 7 -