• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.6
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• pp.918-924
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• 1997

A method for measuring the accuracy of rotating objects was studied. Rotating axis errors are significant; such as the spindle error of a manufacturing machine which results in the surface roughness of machined work pieces. Three capacitance type displacement sensors were used to measure the rotating master ball position. The sensors were mounted to the three orthogonal points on the spindle axis. The measurement data were analyzed and shown for rotating spindle accuracy, not only for average roundness error but also for spindle volumetric positional error during the revolutions. This method is simple and economical for industrial field use with regular inspection of rotating machines using portable equipment. Measuring and analyzing time using this method takes only a couple of hours. This method can also measure microscopic amplitude and 3-dimensional direction of vibrating objects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.91-92
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• 2012

• Smart Structures and Systems
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• v.6 no.4
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• pp.389-403
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• 2010

By using image recognition technology, this paper presents a new fault diagnosis method for rotating machinery with artificial immune algorithm. This method focuses on the vibration state parameter image. The main contribution of this paper is as follows: firstly, 3-D spectrum is created with raw vibrating signals. Secondly, feature information in the state parameter image of rotating machinery is extracted by using Wavelet Packet transformation. Finally, artificial immune algorithm is adopted to diagnose rotating machinery fault. On the modeling of 600MW turbine experimental bench, rotor's normal rate, fault of unbalance, misalignment and bearing pedestal looseness are being examined. It's demonstrated from the diagnosis example of rotating machinery that the proposed method can improve the accuracy rate and diagnosis system robust quality effectively.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.110-117
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• 2004

In automatic welding process using a robot, seam tracking is one of the important parts. Sensor for seam tracking is divided broadly into two categories as non contact sensor and contact sensor. The arc sensor is one of the non contact sensors, and it can be applied in weaving arc and rotating arc welding process. In such the arc sensors, rotating arc sensor can be applied to high speed welding over tens of Hz. The decrease of self regulation by high rotating speed causes to improve accuracy and response of sensor. In this study, fuzzy controller was used to track the seam for the $CO_2$ arc welding which had unstable arc. It could be shown that the rotating arc sensor was better than the weaving arc sensor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.451-452
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• 2006

According to the demand of high productivity, the interest of manufacturing skills is growing in the industrial society. Especially the long spindle becomes important these days. The rotating accuracy of the spindle concerns the centrifugal force. In detail explaining, it is influenced by the speed of the spindle. In this study, we would show changes of the distance caused by a rotating speed of the spindle using a software, $ADAMS^{(R)}$. And because of the gravity of the spindle's mass, we would find the static droop of the long spindle.

• Korean Journal of Remote Sensing
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• v.32 no.5
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• pp.511-527
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• 2016

We propose a rotating stereo frame camera system to acquire indoor images with a low cost. For experiments, we selected a test site and acquired images using the proposed system and control points using a total station. Using these data, we generated various indoor 3D models using commercial photogrammetric software, PhotoScan. We then performed qualitative and quantitative analysis of the generated indoor 3D models to investigate the possibility of the indoor modeling using the proposed system. From the results, it is confirmed that the generated indoor models using the proposed system can be applicable to the services not inquiring high accuracy.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.862-874
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• 1989

A phase evil method and spectrum analysis were instrument error which is originated from measurement system and the form error of standard specimens. An instrument with a rotating table supported by an air bearing is calibrated using standard specimens. The phase of standard specimens was measured 12 times on the rotating table with rotating 30 in turn and its measurement magnification was set by 100000 times. As a result of data analysis of all the observations, read out at each of 144 orientations(per 2.5) from recorded datafiles, the error of the performance of the instrument and those of the standard specimens are evaluated and a systematic deviation of the instrument is determined. In the particular instrument used in the present experiment, the deviation of the instrument is determined with the accuracy of 15nm and those of standard specimens with the accuracy of 23, 13 n, respectively. The reproducibility of the instrument is investigated, too. If the instrument is calibrated by using the above standard specimens, then the accuracy of the measurement of roundness error can be improved to about 15nm.

• Steel and Composite Structures
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• v.19 no.5
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• pp.1279-1298
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• 2015

In this paper, free vibration characteristics of a rotating double tapered functionally graded beam is investigated. Material properties of the beam vary continuously through thickness direction according to the power-law distribution of the volume fraction of the constituents. The governing differential equations of motion are derived using the Hamilton's principle and solved utilizing an efficient and semi-analytical technique called the Differential Transform Method (DTM). Several important aspects such as taper ratios, rotational speed, hub radius, as well as the material volume fraction index which have impacts on natural frequencies of such beams are investigated and discussed in detail. Numerical results are tabulated in several tables and figures. In order to demonstrate the validity and accuracy of the current analysis, some of present results are compared with previous results in the literature and an excellent agreement is observed. It is showed that the natural frequencies of an FG rotating double tapered beam can be obtained with high accuracy by using DTM. It is also observed that nondimensional rotational speed, height taper ratio, power-law exponent significantly affect the natural frequencies of the FG double tapered beam while the effects of hub radius and breadth taper ratio are negligible.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.521-531
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• 2007

Measurement of the vibration transmitted through rotating shafts such as half shafts in vehicles is of interest in applications such as noise transfer analysis and the study of operating deflections. Vibration signals transmitted through a rotating shaft usually include six degree-of-freedom components, thus making the measurement of vibration a challenging task. In the present work, a new measurement method is presented, one that resolves the minimum of only two one-axis accelerometer signals into all components of vibration with reasonable accuracy. The method utilizes the Dopplerized signals obtained from accelerometers attached to a rotating shaft and a Void-Kalman order tracking filter to decompose signals into orders of different vibration components. The new method proposed in the present work is verified by simulated run-up test data and applied to an experimentally obtained data set.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.917-922
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• 2003

In this paper, a high speed rotating arc sensor for automatic fillet welding is introduced. In order to track the welding seam, The high speed rotating arc sensor is used. The welding tip of a high speed rotating arc sensor rotates about 3000 rpm using DC motor. The rotating torch is driven by gear between welding torch body and wire guide. The welding current is measured by using the current sensor and rot at ing position sensor. To realize the welding seam tracking algorithm with accuracy, a software filter algorithm using the moving average method is applied to the measured welding current in the microprocessor. The welding mobile robot with two wheels and two sliders is developed for fillet welding. The welding mobile robot can control its traveling direction and turn itself around the corner. The effectiveness is proven through the experimental results conducted with varied fillet tracking patterns.