电子水平仪英文文献Word格式.docx

1、班 号 指导教师 翻译提交日期 哈尔滨工业大学教务处制Study on a New High Accuracy Dual-axis Electronic LevelAbstractThe study and the development of a new dual-axis, high accuracy and low cost elec-tronic level have been introduced. In this paper, the idea of the overall design is described, and the de-termination for the ma

2、in mechanical and electronic parameters, including the overall testing, has beendiscussed in detail. Based upon the practical characteristic and the specifications of the instrument, it willbe widely used in the field of machine tool, automobile, airplane and shipping manufactures.Key Words: Electro

3、nic level; Plate spring; LVDT; Tilt measurement1 IntroductionThe new dual- axis electronic level is called tilt sensor too. It is a unique tilt measuring system capable of simultaneously recording the degree and direction of tilt with high accuracy up to 1 arc-sec. within a range of 400 arc-sec., up

4、 to 3 arc-sec. within a range of 800 arc-sec. It has a reading resolution up to 0.1 arc-sec.The working principle of the instrument is shown in Fig.1. It is composed of three parts. One part is the combination of the support frame and the base. Another part is stationary work-piece 5 fixed on the to

5、p of sup-port frame. The third part is the swing work-piece 2. The work-pieces 5 and 2 are connected by a pair of double plate springs 3.During measurement if the surface which the instrument is set on is tilt, the whole structure of the instrument will tilt too. But the swing work-piece 2 will move

6、 back along the reverse direction to the tilt by the gravity. Therefore, the coil and the core of the LVDT （linear variable differential transformer） will have relative displacement, and the relative displacement will be converted to analog voltage output. The pair of plate springs are guide way to

7、keep the swing work-piece 2 moving. Fig.1 The structure of the electronic level.Because of the simple structure of the instrument, it is working without wear and tear, also no cross influence upon the function or precision. It is suitable for wide field of application in quality assurance and engine

8、ering, two examples are given as follows. compensate the tilt of a measured equipment can be reached. The purpose of using another head of the instrument is the same as in above example.1.1 Checking the flatness of measuring tablesThe application process is shown in Fig.2（a）. One head of the instrum

9、ent is set on a standard triangular base. During measurement, the triangular base is moved against a ruler step by step. Every step is just equal to a side length of the triangle. Two dimensional tilt data are picked up in every step by a computer. The another head of the instrument is set on a corn

10、er of the measured table to monitor the deformation of the whole table. Usually the micro-deformation of the whole table is caused by the weight of the testing instrument with continuous moving.Fig.2 Application Examples.1.2 Monitoring the level or compensating the tilt of a measuring equipment auto

11、maticallyThis application process is shown in Fig.2（b）. One head of the instrument is set onthe slide stage of a measured instrument or a machine tool. Another head of the instrument is set on the base of the measured equipment. During the slide stage moving, two dimensional errors of the guide way,

12、 pitch and roll errors, are picked up automatically by a computer. Therefore, to monitor the level or to compensate the tilt of a measured equipment can be reached. The purpose of using another head of the instrument is the same as in above example.2 The principle of operationDuring measurement, the

13、 instrument is set up on a surface to be measured and is adjusted to the zero indication with three screws 8. If the surface is tilted a small angle 角度to the horizontal, then the swing part will bear a force F and a force couple M. With the multiple influence of F and M , a deflection Y of the doubl

14、e plate springs will be generated as shown in Fig.3. It can be expressed by the formula （1）:Fig.3 The working situation of the plate springs.Here: E is the elastic modulus of the spring ,I is the moment of inertia. Also （b is the width，h is the thickness of the springs） is known. Because the tilt an

15、gle H isonly within 800 arc-sec.,F=Psincan be written as F=P. Therefore, the formula（1） becomes toUpon the formula （2）, obviously the deflection of the springs is linear with the tilt angle .Suppose the absolute zero of the instrument is just indicating the globe level, then the center of the core w

16、ill coincide with the center of the coil of a LVDT. When a tilt of the surface take place, the two centers of the core and the coil will move relatively following the swing part. The larger of the tilt will lead to the longer of the distance of the two centers. The mechanical displacement will be co

17、nverted to a bipolar dc voltage by LVDT and its subsystem AD598 chip.3 Design of the main systemDuring design, the important factor is to control and decrease the hysteresis of thespring. In order to reach this requirement, two principles should be obeyed: First, the material of the spring should po

18、ssess smaller hysteresis, so we have chosen a kind of spring made of Ni-Ti-Al series alloy that is better for this requirement. Second, during work, the maximum deflection Y should be smaller than the maximum elastic displacement of the spring about 45 times. The maximum elastic displacement of the

19、spring max is :Here is the elastic limit of the spring. Also, considering the whole size of the instrument, we set the length L of the spring to be 60mm, width b =25mm, and thickness h=0.15mm. According to the formulae （2） and （3）, we set the maximum deflection of he spring Y to be 0.2mm, within the

20、 maximum working range =800 arc-sec.Based on the requirements of the range and 0.1 arc-sec. resolution, we can get the requirements for choosing LVDT. Miniature type of LVDT, MHR series （010MHR）, is chosen. Its specifications are listed in Table 1.Table 1The circuit for conjunction with LVDT to conv

21、ert transducer mechanical position to abipolar voltage with a high degree of accuracy and repeatability is shown in Fig. 4. We choose an integrated circuit chip AD598. The AD598 contains a low distortion sine wave oscillator to drive the LVDT primary. The LVDT secondary output consists of two sine w

22、aves that drive the AD598 directly. The AD598 operates upon the two signals, dividing their difference by their sum, producing a scaled bipolar dc output. For a full-scale displacement of Y=0.2mm, the voltage output of the AD598 is computed by formula （4）:Where S=126mV/（V#mm） is LVDT sensitivity ,Vo

23、ut =4V is the full range output voltage ,d is measuring range, here VA+VB=2.7V. Based on the formula （4）, we get the value R2=280kThe output dc voltage is then connected to a 16 bits A/D converter 9015. The full scale output from AD598 is 4V analog. So the 800 arc-sec. is respected with about 25600

24、bits digit. In order to get stable reading, the converted bits are divided by 4. Therefore, 8 bit is equal to 1 arc-sec.Fig.4 AD598 for dual supply operation.Fig.5 Calibration and overall testing.4 Calibration and overall testThe calibration is shown in Fig.5. The dual-axis electronic level is set o

25、n a measuring fixture 4 which has been tested. When the fixture is working, there is about 0.10.2 arc-sec. of roll movement around the beam direction of the HP interferometer. The target of double retroreflectors is set on the fixture too. The HP interferomreter and part of the angle system are fixe

26、d on a stage with fixture 4 together. First, the instrument is calibrated against HP laser with the number of bits. After calibration, the equivalent values between bits and tilt angles are known. Therefore, the read-out of the instrument can be expressed by angle value. We use the same apparatus as

27、 shown in Fig.5 to do the overall testing. During testing the top plate of the fixture is upand down to make different angles through turning a screw. The testing data are listed intable 2.Table 2 gives out the testing data for positive direction and positive return direction of X axis of the electr

28、onic level. There are a set of data for minus direction and there are two sets of data for Y axis of the electronic level. All other testing results are the same as the data shown in Table 2. Based on the testing data, we can say that the maximum uncertainty of the instrument within 300 arc-sec. is

29、better than 1 arc-sec.5 ConclusionThe new dual-axis electronic level has a simple mechanical structure, but high accuracy and feasible for using and adjustment. This achievement is owe to the compact mechanical body, a few integrated circuit chip with only several electronic external passive compone

30、nts engaged in the work, also owe to the quality of the plate spring, the better linearity of the LVDT, the satisfactory stability of the AD598 circuitry. Due to the dual-axis function plus double sets can be connected together to do a measuring project, the new electronic level can ensure a measuri

31、ng process more reliable and more reasonable. So it is very useful and very easy for the wide applications in the field of industry.References1 Wang Baoguang , Mao Yunying. Study on the structure design of a high accuracy 3D probe. Journal of Tianjin University, 1993, （1）:76842 Chen Lincai. Design o

32、f precision instrument. 1sted. Beijing: Mechanical Industry Express, 1991,3 Signal conditioning components & subsystem. Handbook, ANALOG DEVICES: 13234 Linear & angular displacement transducers. Hand-book, Company Lucas Schaevitz一种高精度的新型双坐标电子水平仪的研究摘要 介绍一种新型的高精度、双坐标、低成本电子水平仪的研究与开发。论述了其总体设计思想,并对机械、电子等主要参数的确定方法及精度检定等进行了深入的讨论。通过对仪器的实用性和精度指标的分析,表明该仪器在机床、汽车、飞机和轮船等制造领域有着广泛的应用前景。关键词: 电子水平仪 片簧 线性差动式变压器（LVDT） 倾斜角度测量1 引言型的双轴电子水平倾角传感器。这是一个独特的倾斜测量系统能够同时记