Practical Rotary Encoder Accuracy Limits for Transmission Error Measurement

1991 ◽  
Vol 205 (6) ◽  
pp. 431-436 ◽  
Author(s):  
J D Smith
Keyword(s):  
Angular Position ◽  
Transmission Error ◽  
Electrical Noise ◽  
Error Measurement ◽  
Rotary Encoder ◽  
Revolution Frequency

Errors of angular position on encoders used for transmission error measurement were investigated to determine the practical limits of accuracy. Computer correction can be used to eliminate consistent errors on the encoders but errors remain, attributable to electrical noise, bearing errors and friction effects. Practical limits on the calibration and usage of the encoders for individual harmonics of once per revolution frequency and for a given angular position were established.

OS1-3 Engagement of micro gears and development of micro rotary encoder for transmission error measurement

2011 ◽  
Vol 2011 (0) ◽  
pp. 5-6
Author(s):  
Syuhei KUROKAWA ◽  
Yoji UMEZAKI ◽  
Yoji MATSUKAWA ◽  
Osamu OHNISHI ◽  
Michio UNEDA ◽  
...  
Keyword(s):  
Transmission Error ◽  
Error Measurement ◽  
Rotary Encoder

A New Numerical Algorithm for Transmission Error Measurement at Gears Meshing

2012 ◽  
Vol 472-475 ◽  
pp. 1563-1567
Author(s):  
Ai Jun Xu ◽  
Xiao Zhong Deng ◽  
Jing Zhang ◽  
Kai Xu ◽  
Ju Bo Li
Keyword(s):  
Numerical Algorithm ◽  
Angular Resolution ◽  
Angular Displacement ◽  
Transmission Error ◽  
Comparison Method ◽  
Dynamic Measurement ◽  
Driving Mechanism ◽  
Error Measurement ◽  
Measurement Algorithm ◽  
Constrained Conditions

Many different methods have been developed for the measurement of transmission error (T.E.) at gears meshing. Each strategy improved the measurement performance is based on comparing the phases of sequence signals by counting the number of encoder pulses. The phase comparison method of T.E. is a dynamic measurement algorithm with lower angular resolution and many constrained conditions. This paper presents a new numerical algorithm aimed to provide the high accuracy information of instantaneous T.E. in the form of angular displacement. The analysis approach uses phase shift and demodulation technology in frequency domain to process the signals generated by encoders fixed on the both shaft of the gear driving mechanism. Finally, the algorithm is tested by simulation of gear meshing signal in Matlab software.

Measurement of Joint Element Transmission Error in a Humanoid Walking Robot

2012 ◽  
Vol 566 ◽  
pp. 348-352 ◽  
Author(s):  
Kiyoto Itakura ◽  
Hitonobu Koike ◽  
Katsuyuki Kida ◽  
Kenji Kanemasu
Keyword(s):  
Humanoid Robots ◽  
Power Input ◽  
Transmission Error ◽  
Error Measurement ◽  
Harmonic Drive ◽  
Walking Robot ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Joint Element ◽  
Ether Ketone

In the present work, a prototype of a joint element to be used in lightweight and compact joints for tall humanoid robots is investigated. The newly developed element consists of a harmonic drive gearing device, a multi axis mechanism and a resin bush. Bushes produced from two kinds of bush materials: poly-ether-ether-ketone (PEEK) and polyacetal (POM) were tested. Furthermore, two testing machines to evaluate the joints were constructed: for the power input-output transmission error measurement and for the investigation of the influence of walking-load on bush wear.

scholarly journals From Transmission Error Measurements to Angular Sampling in Rotating Machines with Discrete Geometry

2005 ◽  
Vol 12 (2) ◽  
pp. 149-161 ◽  
Author(s):  
Didier Remond ◽  
Jarir Mahfoudh
Keyword(s):  
Discrete Geometry ◽  
Signal To Noise Ratio ◽  
Transmission Error ◽  
Operating Conditions ◽  
Spectral Amplitude ◽  
Error Measurement ◽  
Rotating Machines ◽  
Analysis Window ◽  
Sampling Procedures ◽  
Monitoring And Measurement

The benefits of angular sampling when measuring various signals in rotating machines are presented and discussed herein. The results are extracted from studies on transmission error measurements with optical encoders in the field of power transmissions and can be broadened to include phase difference measurements, such as torsional vibrations, and applied to control, monitoring and measurement in rotating machines with discrete geometry. The main conclusions are primarily that the use of angular sampling enables the exact location of harmonics and, consequently, the obtaining of spectral amplitude components with precision. This is always true even if the resolution of encoders is not directly related to the studied discrete geometry. It then becomes possible to compare these harmonics under different operating conditions, especially when speed varies, without changing any parameters in spectral analysis (window length, spectral resolution, etc.). Moreover, classical techniques of improving signal to noise ratio by averaging become fully efficient in the detection of defective elements. This study has been made possible thanks to the technique of transmission error measurement with optical encoders that allows the comparison of sampling procedures, based on the same raw data.The intensive use of such transducers and the development of an original transmission error measurement technique lead to advocate the use of angular sampling in experimental measurements in rotating machines with discrete geometry.

High Resolution SelfA Rotary Table by the Interpolation Signal Calibration

2014 ◽  
Vol 625 ◽  
pp. 53-59
Author(s):  
Tsukasa Watanabe ◽  
Watcharin Samit ◽  
Ketsaya Vatcharanukul ◽  
Anusorn Tonmueanwai ◽  
Agustinus Praba Drijarkara
Keyword(s):  
High Resolution ◽  
Position Control ◽  
Angular Position ◽  
High Accuracy ◽  
Rotary Table ◽  
Angle Error ◽  
Rotary Encoder ◽  
Angular Interval ◽  
Scale Error ◽  
Good Repeatability

Self-A (Self-calibratable Angle device) rotary encoder can detect some kinds of angle error, not only its encoder scale error, but also the encoder attachment error (e.g. eccentricity error). When rotary table with built-in Self-A encoder rotates only one revolution, inner Self-A rotary encoder can calibrate the own angle error with a high accuracy. However, in the case of the Self-A using the encoder of 36,000 graduation scales, since the angular interval of the calibrated main scales corresponds to 36", it is insufficient for high resolution angular indexing control with high accuracy. Generally, the angle error of electric interpolation signal is estimated to be 1 % of main scale resolution that corresponds to about 0.36" for 36,000 scales encoder. Accordingly, even if Self-A had the ability which can calibrate in the accuracy 0.1", when it was controlling the rotary table using an electric interpolation signal, its total accuracy worsened to about 0.36". For improvement in precise angular-position control, we developed Self-A rotary table which can calibrate the angle signal at high resolution including electric interpolation signals. In this paper, we introduce the performance of the new high resolution Self-A encoder table. It keeps high accuracy and good repeatability in the 360° whole range as well as in the short range of ±1,000".

A Modular System for Transmission Error Measurement

1988 ◽  
Vol 202 (6) ◽  
pp. 439-442 ◽  
Author(s):  
J D Smith
Keyword(s):  
Transmission Error ◽  
Modular System ◽  
Belt Drive ◽  
Error Measurement ◽  
Input And Output ◽  
Speed Range ◽  
Toothed Belt ◽  
Synchronous Drive

A modular system of electronics for measuring transmission error with standard rotary optical encoders is described. The system can work flexibly with an overall speed range of the order of a 1000 to 1 by changing the order of the modules and will respond correctly to speed variations in both input and output of a synchronous drive such as a gear, chain or toothed belt drive.

Accuracy of small encoders for gear transmission errors

2001 ◽  
Vol 215 (8) ◽  
pp. 995-998 ◽  
Author(s):  
J. D. Smith
Keyword(s):  
Production Control ◽  
Transmission Error ◽  
Gear Transmission ◽  
Development Work ◽  
Error Measurement ◽  
Gear Noise ◽  
Transmission Errors ◽  
Gear Drives

For noise investigations and development work or precision production control of gear drives there are major advantages to using small encoders for transmission error measurement in situ owing to reduced size, inertias and cost. As there was uncertainty concerning the accuracies that would be obtained in practice, a small encoder was calibrated and found to be surprisingly accurate at those frequencies of importance for gear noise.

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