• 소음진동
• /
• 제2권1호
• /
• pp.49-59
• /
• 1992

The motion analysis of a translation device driven by a piezoelectric actuator is performed to identify the mechanics of impact drive mechanism and to find the maximum speed waveform. The translation device is modeled as a semidefinite two-degree-of-freedom system. The motion analysis includes effects of friction force between moving mass and contact surface, dynamics of voltage amplifier and piezoelectric elements, and hysteresis of piezoelectric actuator. Base on the model, simulation studies are carried out and then compared with experimental results. It is found that the error between moving distances obtained by analysis and experiment is less than 15% and that the actual motion of moving mass is well predicted by the analytical work, finally, precision positioning experiments are carried out by using a proximity sensor as a feedback sensor. Position control of moving mass is initiated by the maximum speed waveform and finely tuned by the scaled down waveform so that accurate positioning is accomplished within the resolution of the sensor.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.793-799
• /
• 2004

In track a third weakness point is joint part, turnout part, curve part. One of them joint part of rail have been known to the most weak point by loosen of joint bar and fish bolt due to impulse and vibration by wheel contact at times. In addition happen to deformation and failure at end of rail, failure and miniature of ballast gravel. Finally impact between wheel and rail become origin cause of a welded rail, noise and vibration. riding condition deterioration, besides track failure. In the present domestic, Thermite and Gas pressure weldings have been used to continuous welded rail(CWR), however stiffness and confidence in quality is lower than Flash butt welding method. FRW have the excellent capacity, however have a shortcoming large scale of machine and power equipment. Therefore we will introduce Mobile Flash Butt Welder can weld in track.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.283-289
• /
• 2004

Rail defects(Corrugation, shelling, etc) are occurred by the Rail with wheel contact stress. Rail grinding is maintaining of optimal rail profile to use special rail grinding machine to remove rail defect. The benefits of rail grinding enforcement, improve track safety, improve track steering and rail life, improve ride comfort and reduce noise, etc. Actually when rail grinding plan apply to field track, we should consider a lot of function before determination, such as grinding method, grinding pass number, removing metal volume, etc. because each track has various characteristics. Therefore it is important that the determination of rail grinding strategy for optimum and economic before enforcement.

• 드라이브 ㆍ 컨트롤
• /
• 제14권3호
• /
• pp.25-31
• /
• 2017

This study presents a methodology for simulating a unified approach that controls interaction force between tool and objective by using a synthesis method of robot interacting control law for stabilizing the transient process of motion. Root locus is used to analyze stabilization of motion deviation characteristics. Based on responses of motion deviation, contact force is derived to satisfy exponential stability and we generate control input with respect to motion trajectories and interaction force. Moreover, simulation is applied to experimental application of a Cartesian robot driven by two stepper motors, and the noise of feedback signals is considered as presence of system inaccuracies, and the unified approach of interaction force control is examined precisely.

• 한국전기전자재료학회논문지
• /
• 제30권4호
• /
• pp.253-257
• /
• 2017

Nowadays, it is increasingly important to detect whether cables are live for the operator's safety if there is a sudden power failure. It is especially hard to detect the electrical field of an underground line because of shielding. This paper on detection of live-line states in cables studied the detection characteristics of the change in the magnetic field and axis as the frequency, voltage, and distance at the same load are changed using 3 axes. A search coil type was used as a magnetic field sensor with non-contact. We found that magnetic fields decrease proportionally to the square of the distance and the decrease of rated voltage with load effected to magnetic field. The magnetic field was detected by 3-axis sensors given correct proximity, but appeared as noise components beyond a distance of 2 cm.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.469-470
• /
• 2007

In this paper, we propose a simple and relative electrode contact monitoring method. By exploiting the power line interference, which is regarded as one of the worst noise sources for bio-potential measurement, the relative difference in electrode impedance can be measured without a current or voltage source. Substantial benefits, including no extra circuit components, no degradation of the body potential driving circuit, and no electrical safety problem, can be achieved using this method. Furthermore, this method can be applied to multi-channel isolated bio-potential measurement systems and home health care devices under a steady measuring environment.

• 한국기계가공학회지
• /
• 제13권6호
• /
• pp.99-103
• /
• 2014

A hypoid gear is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The size of a hypoid gear is compact and the ratio of contact is high; therefore, the noise is lower than in other types. Due to these characteristics, the hypoid gear is commonly used in manufacturing processes such as those of escalators and subway screen doors. The purpose of this paper is to develop a reducer using the hypoid gear. In order to check the stability of the proposed reducer, 3D modeling is carried out by CATIA, and a structural analysis is performed using FEM (a finite element method).

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2004년도 추계학술대회
• /
• pp.165-170
• /
• 2004

It used the flow system of the stone polishing machine head and it developed a multi axis whetstone polishing system. With the result, the defect by line contact polishing does not occur in both ends of the stone, and it came to trim smoothly. As the index of the surface roughness decreased to 3.6 times, the polishing effect improved greatly. It decreased greatly the dust and a noise with the wet polishing, and the factors of the duty evasion at production site were solved with the work environment improvement against the polishing process of the stone industry and work intensive reduction.

• 동력기계공학회지
• /
• 제17권4호
• /
• pp.139-146
• /
• 2013

Because the magnetic bearing supports levitating body without contact, wear, noise and vibration, it is very useful to high revolution machinery. In this paper we selected ATmega 128, a less expensive and widely used micro controller, for control the magnetic bearing system. And we selected the sampling time and the control gain of PID controller through trial-and-error. The control program of the one board controller utilized lookup table to reduce calculation time, and bit shifting for the integer calculation in instead of floating point calculation. As the results, the controller carried out relatively high speed PID control on sampling time 0.25 ms. At last the rotation test for the magnetic bearing system was carried out by 3 phase induction motor and air turbine.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 1998년도 추계학술대회 논문집
• /
• pp.530-536
• /
• 1998

In the design of the light rail transit which is more reliable and economical, it is essential to develope a efficient third rail system. Especially, the analysis for the conductivity of conduct rail and the wear of collecting shoe is the first step of its development. In this paper, experiments for conductivity in conductor rail, wear in collecting shoe were performed respectively as different materials of conductor rail and current collector. Noise level and interruption, wear and contact resistance of collecting shoe were proposed as design parameters for the development of this system. Experimental equipment and methods of design parameter stated above were proposed, which is expected that analyzed results will be used as a basic data for the development of the system.