• Transactions of the Korean Society of Mechanical Engineers
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• 제17권10호
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• pp.2437-2445
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• 1993

In this work, a new method is presented for generating the manipulator path which significantly reduces residual vibration under the torque constraints. The desired path is optimally designed so that the required movement can be achieved with minimum residual vibration. From the previous research works, the dynamic model had been established including both the link and the joint flexibilities. The performance index is selected to minimize the maximum amplitude of residual vibration. The path to be designed is developed by a combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems. The concept of correlation coefficients is used to select the minimum number of design variables, i.e. Fourier coefficients, the only ones which have a considerable effect on the reduction of residual vibration. A two-link Manipulator is used to evaluate this method. Results show that residual vibration can be drastically reduced by selecting an appropriate manipulator path to both of unlimited and torque-limited cases.

• Journal of Power System Engineering
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• 제7권1호
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• pp.34-41
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• 2003

A method is presented for generating the path which significantly reduces residual vibration of a flexible robot manipulator and applying control theory to track the desired path. The desired path is optimally designed so that the system completes the required move with minimum residual vibration. A closed loop control theory is applied to track the planned path in the case of load variation. Specifically, it is desired that the optimally designed path has a better trajectory tracking capabilities during the residual vibration over the cycloidal path, in various cases of load. Perturbation adaptive control is used as closed loop control scheme. A planar two link manipulator is used to evaluate this method.

• Journal of Power System Engineering
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• 제5권2호
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• pp.79-86
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• 2001

A method is presented for generating the path which significantly reduces residual vibration of the redundant, flexible robot manipulator in the presence of obstacles. The desired path is optimally designed so that the system completes the required move with minimum residual vibration, avoiding obstacles. The dynamic model and optimal path are effectively formulated and computed by using special moving coordinate, called VLCS, to represent the link flexibility. The path to be designed is developed by a combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems. The concept of correlation coefficients is used to select the minimum number of design variables. A planar three-link manipualtor is used to evaluate this method. Results show that residual vibration can be drastically reduced by selecting an appropriate path, in the presence of obstacles.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.602-603
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• 2008

The design modification of problematic component in a given vibration path is disallowed in order to sacrifice other performances such as ride comport or handling of a vehicle. For this, the paper presents a new contribution analysis based on transmissibility ratio (TR) of acceleration in a definite vibration path to find a proper candidate for design modification. The new contribution analysis is based on the fact that the sensitivity of TR over a small design change is inversely proportional to the magnitude of TR. The new methodology can significantly relieve efforts of time-consumming modal analysis for detail modal information. The theory of proposed contribution analysis is simulated with five-degree-of-freedom open vibration path and confirms that the contribution result is well matched with the variance of TR over a dynamic change on a vibration path.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제20권11호
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• pp.1071-1077
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• 2010

The reduction of the vehicle interior noise has been the main interest of noise and vibration harshness(NVH) engineers. A passenger vehicle has various and complicated transmission paths of sound and vibration. In order to identify the mechanism of transfer path, estimation of excitation force and exact modeling of transfer path are required. This paper presents method for estimating the noise source contribution on the road noise of the vehicle in a multiple input system where the input sources may be coherent with each other. And vector synthesis technique is employed to identify the characteristics of road noise and its transmission to vehicle compartment through noise and vibration analysis. Vibration reduction efficiency of each transfer path is evaluated by comparing individual vector components obtained virtual simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 1990년도 추계학술대회논문집; 한양대학교, 서울; 24 Nov. 1990
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• pp.181-185
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• 1990

In the present study, the following factors are analyzed systematically using the theoretical and experimental methods, which have the significant influence on the quality of VTR tape path system in order to develope the high performance and quality in VTR mechanism: 1) Vibration characteristics of the deck including the tape path sytem, 2) Modeling the global tape path, 3) Torsional vibration of the VTR drum. 4) Capstan system, 5) Tension bar, 6) Stick-slip phenomenon of the running tape.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제15권3호
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• pp.280-289
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• 2005

A single degree of freedom system and transmissibility are key concepts in many problems of vibration isolation. In order to apply this approach, however, several assumptions must be satisfied, which are often not realistic. For examples, in practical systems, vibration transmissions at multi-point with multi-degree of freedom(translational and rotational DOF) take place and mobilities or impedances of receiver structures cannot be ignored any more especially over high frequency range. Therefore, a multi-dimensional treatment is required for accurate estimation of dynamic behavior of the system. In this paper, an approach using vibrational power flow is introduced to deal with analysis of multi-dimensional vibration isolation system in a more practical way and in aspects of vibration isolations and vibration path analysis. Procedures of this approach and some results of research for vibrational power path analysis with rotational terms included are presented. Difficulties in this method are also discussed.

• Bulletin of the Korean Chemical Society
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• 제13권1호
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• pp.11-17
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• 1992

Vibration-to-vibration energy transfer probabilities for $HF(v=n)+H_2(v=0){\to}HF(v=n-1)+H_2(v=1)$ and $DF(v=n)+D_2(v=0){\to}DF(v=n-1)+D_2(v=1)$ including both the vibration-to-vibration and translation (V-V, T) and vibration-to-vibration and rotation (V-V, R) energy transfer paths have been calculated semiclassically using a simplified collision model and Morse-type intermolecular interaction potential. The calculated results are in reasonably good agreement with those obtained by experimental studies. They also show that the transition processes for $HF(v=1-3)+H_2(v=0){\to}HF(v=0-2)+H_2(v=1)$ and $DF(v=1,\;4)+D_2(v=0){\to}DF(v=0,\;3)+D_2(v=1)$ are strongly dependent on the V-V, T path at low temperature but occur predominantly via the V-V, R path with rising temperature. The vibration-to-vibration energy transfer for $HF(v=4)+H_2(v=0){\to}HF(v=3)+H_2(v=1)$ and $DF(v=2-3)+D_2(v=0){\to}DF(v=1-2)+D_2(v=1)$ occur predominantly via V-V, R path and V-V, T path through whole temperatures, respectively.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제11권9호
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• pp.422-430
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• 2001

An electric drill is a handy tool used in a machine shop, which consists of motor, gear, bearing, shaft, and case, i.e., a gear driving system. Low level vibration and noise of the electric drill can bring the assurance of the quality and reliability of the machine. The vibration sources of the electric drill should be investigated for the reduction of the vibration and noise of the system. Through the experiments in laboratory and the various signal processing procedure for the measured vibration and sound signals, the characteristics of the vibration of the electric drill are investigated. And its propagation path is sought using partial coherence function.

• Journal of Biosystems Engineering
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• 제26권3호
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• pp.237-244
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• 2001

This work was intended to investigate the effect of vibration transmission paths on the ride vibration of tractor during the rotavating and transporting operations by applying the vibration path analysis method. Accelerations at the cab mounts were measured during the rotavating and transporting operations. Ride vibrations at the sear were than calculated using the measured accelerations at the cab mounts, and the frequency response functions and inertances between the seat and cab mounts, which were derived experimentally by the impact hammer test in static condition. The human sensitivity to vibration frequency was also taken into consideration for the calculation of ride vibrations at the 1/3 octave center frequencies in the frequency domain. Vibrations transmitted through rear cab mounts affected more significantly the ride vibration of tractor. The peak accelerations at the seat occurred at the frequencies of the engine and crank speed, and the frequency induced by tire lugs on the road transportation. It was found that the rear cab mounts should be improved in order to reduce the ride vibrations more effectively.