• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.99-109
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• 2015

This study proposes a new approach to analyze the impedance and the elasticity of a serial chain of spring-damper system, areal-time collision-free trajectory generation algorithm is proposed. The reference points on a trajectory connected by the spring-damper system have a mechanism for self-position adjustment to solve a collision problem by the impedance, and the local adjustment of each reference point is propagated through the elasticity to a real robot at the end of the spring-damper system. As a result, the overall trajectory consisting of the reference points becomes free of collision with environmental obstacles and efficient having the shortest distance as possible. In this process,, the reference points connected by the spring-damper system take role of virtual robot as global guidance for a real robot, and a cooperative is carried out by the system of robots. A control technology is proposed to implement for mobile robot.

• Earthquakes and Structures
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• v.13 no.6
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• pp.551-559
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• 2017

A large number of isolation systems are designed without considering the non-uniform friction distribution in space. In order to analyze the effects of non-uniform friction distribution on the structural response of isolation system, this paper presented a simplified rolling-damper-spring isolation system and analyzed the structural responses under earthquakes. The numerical results indicate that the calculation errors related to the peak values of structural acceleration, relative displacement and residual displacement are sequentially growing because of the ignorance of non-uniform friction distribution. However, the influence rule may be weakened by the spring and damper actions, and the unreasonable spring constant may lead to the sympathetic vibration of isolation system. In the case when the friction variability is large and the damper action is little, the non-uniform friction distribution should be taken into consideration during the calculation process of the peak values of structural acceleration and relative displacement. The non-uniform friction distribution should be taken into full consideration regardless of friction variability degree in calculating the residual displacement of isolation system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.305-310
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• 2007

This paper presents a damper system design in torque converter to minimize the vibration in powertrain of automatic transmission vehicle. The lock-up clutch in torque converter makes engine and transmission connected directly. When the lock-up clutch is engaged the torque fluctuation of engine is attenuated by the damper system. This function decides the vehicle power-train dynamic characteristics. At first, the dynamic hysteresis effect with any self and surface to surface contact problems of the damper springs in the damper system for torque converter is analyzed by using FEM. It is shown that these simulation results have a good design reference to energy dissipation operating by damper system in torque converter. And, to calculate dynamic characteristics, the vehicle model is structured by using $AMESim^{(R)}$?? that is a common use program. The vehicle model shows the frequency response of vehicle by changing the stiffness of damper spring, and these results lead the most suitable stiffness of spring. Also, new damper system is analyzed resonance frequency variation and is compared with prior damper.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1264-1268
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• 2004

This paper presents a wafer motion modeling of the transfer unit and the control unit in the clean tube system, which was developed as a means for transferring the air-floated wafers inside the closed tube filled with the super clean airs. The motion in the transfer unit is modeled as a mass-spring-damper system where the recovering force by air jets issued from the perforated plate is modeled as a linear spring. The motion in the control unit is also modeled as another mass-spring-damper system, but in two dimensional systems. Experiments with a clean tube system built for 12-inch wafers show the validity of the presented force and motion models.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2038-2046
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• 1997

In this paper the instability of the system which has a disk and a mass-spring-damper system interacting through a medium having stiffness and damping is analyzed. To solve the equations of motion of this systme, it is assumed that the solution consists of the eigenfunctions which are the products of the Bessel functions and sine or cosine functions. The former represents the radial characteristics of the disk and the latter represents the circumferential characteristics. Using this assumed solution and the orthogonality of the eigenfunctions, the equations of motion can be transformed into a set of equations of motion with variables dependent only on the time. After this set is changed to the state equation, the eigenvalue problem can be made. Once the eigenvalues are calculated according to the angular velocity of the disk, the dynamic characteristics ofthis system is obtained. Because the thickness of the disk and the element characteristics of the mass-spring-damper system have important effects on the stability of the system, it will be understood how these factors affect the system and then a method to ameliorate the stability of the system with a disk will be presented.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.1
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• pp.61-68
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• 2010

This paper proposes networked swarm robotic systems with group based control scheme using spring damper impendence feature. The proposed algorithm is applied to keep system arrangement in unexpected situations based on the spring-damper impedance and fuzzy logic. Using the proposed scheme, each robot overcome collision problems efficiently. The structure of UBSR (UMPC Based Swarm Robot) system consists of user level, cognitive level, and executive level. This structure is designed to easily meet the different configuration requirements for other levels. Simulation results show an availability of the proposed method.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.599-603
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• 2007

An efficient optimum design process has been developed and applied to systematically design a lock-up clutch system for a torque converter used in an automatic transmission. A simulated annealing algorithm was applied to determine the parameters of the compressive helical damper springs in the clutch. The determination of the number, location, a number of turns, and deflection of damper springs plays an important role in reducing vibration and noise in the lock-up system. Next, FE-based shape optimization was coded to find the shape of the clutch disk that would satisfy the strength, noise and vibration requirements. Using the optimum code, parametric studies were performed to see how spring diameters and frequencies of clutch systems changed as the damper spring traveling angles and the torques were varied. Based on the optimum results, five different designs for clutches with different springs were fabricated and vibration analyses and tests were conducted to validate the accuracy of the proposed method. Results from the two methods show a good correlation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.153-158
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• 2000

The purpose of present paper is to prove an improvement on stability of plane Journal bearing due to the leaf spring damper(LSD) experimentally A flexible rotor system is designed and manufackuea in order to generate oil whip instability of journal bearing at relative lower rotating speed. Vibration amplitude and instability onset speeds are investigated for a conventional plane journal bearing and plane journal bearing with LSD. To investigate the damping effects of LSD on stability of bearing, experiments are also conducted on the leaf spring dampers with and without working oil. It is found that the leaf spring damper can considerably increase the instability onset speed of a plane journal bearing.

• Tribology and Lubricants
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• v.17 no.3
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• pp.185-190
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• 2001

The purpose of present paper is to prove an improvement on stability of plane journal bearing due to the leaf spring damper (LSD) experimentally. A flexible rotor system is designed and manufactured, in order to generate oil whip instability of journal bearing at relative lower rotating speed. Vibration amplitude and instability onset speeds are investigated for a conventional plane journal bearing and plane journal bearing with LSD. To investigate the damping effects of LSD on stability of bearing, experiments are also conducted on the leaf spring dampers with and without working oil. It is found that the leaf spring damper can considerably increase the instability onset speed of a plane Journal bearing.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.87-92
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• 2000

In order to improve the instability of Plane journal bearing, it is introduced the leaf spring damper(LSD). The effects of dynamic characteristics of LSD on the stability of a plane journal bearing were investigated theoretically. The improvements on the stability of a plane journal bearing with LSD. are compared with the results of a floating ring journal bearing and of journal bearing without LSD. It found that a plane journal bearing with LSD will be an effective way in the improvement on the stability of rotor system.