A comprehensive test system for precision transmission performance of CORT reducer

Transcription

1 Applied Mechanics and Materials Online: ISSN: , Vols , pp doi: / Trans Tech Publications, Switzerland A comprehensive test system for precision transmission performance of CORT reducer Yong Li a, Guang Ma b, Yunde Shen c, Taihong Chen d, Zhenzhe Li e, Dongji Xuan f, and Ming Ren g College of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou, China a lyre@wzu.edu.cn, b ma_guang@163.com, c shenyunde63@yahoo.com.cn, d cth315@gmail.com, e zhenzheli1978@gmail.com, f xuandongji@163.com, g wzrm@wzu.edu.cn Keywords: CORT reducer; transmission performance; test system; LabVIEW Abstract: To meet the needs of test for compound oscillatory roller transmission (CORT) reducer, A comprehensive test system for precision transmission performance was designed, the test-bed structure and control principal of which were introduced. First, a transmission performance test method was proposed and focused on the transmission performance of velocity ratio, accuracy, and efficiency. Then, user interface based on LabVIEW program was designed, and the transmission performance of torque, angle, velocity, velocity ratio, return difference, efficiency could be displayed. Finally, measurement example on an E80 type CORT reducer has been made, and shows that the proposed test system is suitable for test for these reducers of high-precision drive, high stiffness, high load characteristics. Introduction Roller Transmission is a new advanced transmission technology developed in the last 20 years. The roll transmission gear has extremely carrying capacity, can achieve high-precision and high stiffness output.[1,2] According to these unique advantages, in the late 1990s high-precision, high-stiffness compound rolling live transmission gear was developed. Such precision reducer is particularly applicable to robots, CNC equipment, aerospace equipment, defense equipment and weapons requirements of high-precision control of the transmission system.[3,4] CORT reducer is based on the drive of oscillatory transmission, a series gear branch input multi-synchronous input shaft roller power transmission to ensure that it covers a high-precision drive, high stiffness, high load characteristics. Test technogly for the reducer got a lots of attentions by researchers. [5-7] To value the performance characteristics of the CORT reducer, a comprehensive test system for precision transmission performance of the CORT reducer is designed. The structure, scheme, methods and application of the test system are discussed in following chapters. System description The test system is essentially comprised of two parts, which are the test-bed and the control module. The essential components of the test-bed are serve motor, torque and angle sensors, the CORT reducer, magnetic loader, couplings, etc. Control module is supported by National Instrument LabVIEW-controlled PXI hardware, and automatic drive, loading control, data display, data logging, and signal analysis can be realized by software part. The structure and principal of two parts are: Structure of the test-bed. The test-bed shown in Figure. 1, includes servo motor, input and output sensors, the CORT reducer, magnetic powder loader, bed plate, etc. The servo motor is connect to first coupling, input torque and angle sensor, second coupling, the CORT reducer, third coupling, output torque and angle sensor, fourth coupling, and magnetic loader in sequence. The connected assemblies are adjusted by four corresponding brackets to guarantee horizontal coaxial alignment. The torque and angle sensor is fabricated as an entirety, comprised of the strain gauge torque sensor All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-03/03/16,23:25:12)

2 Applied Mechanics and Materials Vols and the absolute photoelectric encoder angle sensor. As the CORT reducer has large velocity ratio, compared to the input torque and angle sensor, the output torque and angle sensor has larger torque range and higher angle resolution ratio servo motor 2. first coupling 3.input torque and angle sensor 4.second coupling 5.the CORT reducer 6.third coupling 7.output torque and angle torque 8.fourth coupling 9.magentic loader 10.motor bracket 11.input senor bracket 12.reducer bracket 13.output sensor bracket 14.bed plate Figure. 1 Structure of the reducer test-bed LabVIEW platform Data acquisition card Inverter Load amplifier Servo Input torque and The CORT Output torque Magnetic motor angle sensor reducer and angle sensor loader Bed plate Figure.2 Control module flow chart of the reducer test system principal of control module. Control module is to achieve speed and position control of the servo motor, sensor data acquisition and transmission and magnetic loader loading, thus the control mode and the collect data could be displayed on the computer screen through the user interface of LabVIEW platform. The specific flow chart is shown in Figure. 2. The principal of control module works is described as following. First, LabVIEW platform sends signal to the inverter and the loader amplifier by the data acquisition card. After receiving the command of the inverter, the servo motor could be realized in either speed or position control mode, and rotate along with the reducer. The torque loading is realized by the magnetic loader, and the value is nearly proportional to the input signal of

3 2450 Measurement Technology and Engineering Researches in Industry loader amplifier by the. Second, when the reducer is running, the torque and angle of both input and output rods could be measured by two above sensors and transmitted to LabVIEW platform by the data acquisition card. The CORT reducer has different transmission performance under various loading condition. Finally, the transmission performance parameters can be calculated from the obtained data, and displayed in form of value or figure. Method and Metric The most important parameters of transmission performance include velocity ratio, return difference, and efficiency. Those parameters can be obtained by collecting the values of the torques and angles. The test can be realized in following methods and metric: Velocity ratio test. When enable servo motor to operation in stable status, the input and output angle could be obtained by the angle sensors of photoelectric absolute encoders. As the input and output angle are respectively set to Horizontal and vertical ordinate of a curve. The curve could be fit to be a straight line, the slope of which is regarded to be the velocity ratio. Return difference. When the input rod of the reducer keeps rotating in stable status, the output rod would rotate in same direction. If the rotating direction of the input rod changes to opposite suddenly, the output rod would decay a slight angle after following the change. So the decay angle is an important parameter of transmission accuracy, and normally called return difference. In order to measure the value, the servo motor should be controlled in both positive and negative directions. Then a hysteresis curve with horizontal ordinate of output angle, vertical ordinate of input angle could be obtained, and the value of hysteresis horizontal error is regarded to be return difference. If the reducer operates under different loading condition, a curve about the influence rule of the various loading on return difference could be obtained. Efficiency. When reducer operates under certain torque and speed, the input and output torque could be measured by two torque sensors. So the efficiency could be deduced, which is a function of transmission ratio, the input and output torque. If the reducer operates under different loading condition, a curve about the influence rule of load value on efficiency could be obtained. So the transmission performance could be measured simultaneously by the test system in above method and metric, especially for the CORT reducer with high-precision, high stiffness, high load characteristics. User interface based on LabVIEW program To reduce the operation requirement of test for user, LabVIEW program is used to realize automatic control and provide intuitive user interface. The information of user interface is introduced as following. The transmission performance of torque, angle, velocity, velocity ratio, return difference, and efficiency could be displayed in one user interface, as shown in figure 3. The procedure of test is: First, if click run, the sensors could measure the torque and angle of both input and output reducer rods, and the value would update real-timely. Second, if click return difference, the servo motor would run in a low speed for two cycles of positive direction, then another two cycles of negative direction. As a result, the figure of angles hysteresis curve could be plotted in the user interface, so that the return difference could be measured from the figure, which is the maximum distance of horizontal hysteresis. Third, if click efficiency, the values of required speed and load should be set first, then the servo motor would speed up to given value under certain load. After running stably for a few minutes, the velocity ratio and efficiency could be measured and displayed. To change another given condition, we just update the given values of speed and load. The efficiency would be updated as the condition changes, and the figure about relation of efficiency and torque could be plotted in the user interface.

4 Applied Mechanics and Materials Vols The LabVIEW program could support the test work, and is omitted in the paper. Figure.3 User interface of the reducer test system Figure.4 The comprehensive test system Measurement example Finally, a CORT reducer of E80 type is tested based on the comprehensive test system, as shown in Figure. 3 and Figure. 4. As a result of the experiment, the transmission performance of torque, angle, velocity, velocity ratio, return difference, and efficiency are measured. From the figure, it can be seen that the servo motor was running in load condition of 100N.m(10% rated value) and velocity of 1000 r/min, input and output torque of the reducer is respectively 2.43N.m and 100 N.m, speed ratio of 80.4, return difference of 18.8 minutes, efficiency of 51.2%. Conclusions A comprehensive test system for precision transmission performance of the CORT reducer was designed, and the test-bed structure and control principal of that were introduced. The transmission performance test method was proposed, and user interface based on labview platform was developed. Experimental work of test for a CORT reducer of type E80 has been done, and shows that the system s advantages are proved by its high measuring precision, small errors and flexibility, especially for these reducers of high-precision drive, high stiffness, high load characteristics. The user interface is intuitive and convenient to operate, and automatic control could be realized. Acknowledgements This work was financially supported by National High Technology Research and Development Program of China(863 Program: KZ ). References [1] J.B. Wu, and H.M. Cheng: 2010 International Conference on Computer Application and System Modeling, Vol. 12(2010), p. 296 [2] L.N Xu: Xi an university of science and technology, Master dissertation(2009) (In Chinese) [3]Y.Q. Yang, X.M. Liu, Q. Yu, and S.X. Chu: Journal of Beijing university of technology, Vol.32(2006), No.1, p. 21(In Chinese) [4] J.F. Wu: Journal of Guangzhou university(natural science edition), Vol. 1(2002), No, 5, p. 8(In Chinese) [5] A.A. Topalov, I. Katsounaros, J.C. Meier, S.O. Klemm, and K.J.J. Mayrhofer: Review of Scientific Instruments, Vol. 82(2011), p [6] X.H. Li, C.K. Gao, and Y.Y. Pi: Lifting the transport machinery, Vol. 5(2009), p. 48(In Chinese) [7] P.V. Nikitin, and K.V. Seshagiri Rao: IEEE Transactions on Industrial Electronoics, Vol. 56(2009), No. 7, p. 2374

5 Measurement Technology and Engineering Researches in Industry / A Comprehensive Test System for Precision Transmission Performance of CORT Reducer / DOI References [5] A.A. Topalov, I. Katsounaros, J.C. Meier, S.O. Klemm, and K.J.J. Mayrhofer: Review of Scientific Instruments, Vol. 82(2011), p /