• 기계와재료
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• v.25 no.3
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• pp.130-136
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• 2013

철도차량용 제동장치 성능시험기는 제륜자의 마찰계수, 마모량, 열반점 등의 물리적 성질을 실차와 유사한 환경조건에서 시험을 수행함으로써 제륜자의 연구개발 및 성능평가의 목적으로 활용한다. 제륜자는 차량의 운동에너지를 열에너지로 변환한다. 성능시험기는 철도차량의 주행 운동에너지에 해당하는 관성질량으로부터 회전 운동에너지에 해당하는 관성모멘트를 조성하여야 한다. 공용 시험기에서 각종 철도차량에 대한 관성모멘트를 기계적 관성모멘트인 플라이휠로 모의하기에는 용량도 크고 구조가 복합하여 현실적으로 한계가 있다. 본 연구에서는 기계적 관성모멘트의 한계를 극복하고자 전기적 관성모멘트를 부가적으로 활용하는 기법을 제시하고 이를 적용한 시험기를 소개하고자 한다. 이러한 연구는 시험기의 외형적인 크기를 줄이고 또한 각종 철도차량에서 요구하는 정량적인 관성질량의 모의가 가능하리라고 사료된다.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.119.2-119.2
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• 2009

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.395-402
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• 2016

This paper presents a design methodology for improving the energy efficiency by considering the inertial properties of serial manipulators. This method employed is to put the inertia matrix, which has a critical effect on the equation of motion, into the constraints of the optimization problem. Through the optimization process, we propose a design algorithm that can double-check whether the optimized parameters satisfy the required performance or not by using an auxiliary index associated with the inertia and energy. Using this design algorithm, we were able to improve the energy efficiency by minimizing the torque. We applied this method to a 3 degrees of freedom serial manipulator and simulated it.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.266-273
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• 2003

A wind turbine simulator is developed for the emulation of variable input torque from the wind energy without actual rotor blades using motor-generator set. The torque command of dc motor is calculated from the characteristic equation of rotor blade during the change of wind speed. Especially the proposed control algorithm takes into account the fact that the moment of inertia of blade is much larger than that of driving motor. If you select the desired value of inertia, the stored/restored energy of the inertia during acceleration/deceleration can be compensated effectively resulting the only net torque is delivered to the generator. The simulator set-up has been designed and implemented using a do motor and drive. Feasibility of the proposed algorithm is verified by computer simulations and experiments.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.171-171
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• 2022

난류 수체에서 관성입자의 침강속도는 정지 수체에서보다 빠르고, 그 침강속도의 증가비율은 입자의 관성력과 난류의 길이 스케일에 큰 영향을 받는다고 알려져 있다(Wang and Maxey, 1993; Yang and Shy, 2003; Wang et al., 2018). 본 연구에서는 개수로 흐름에서 난류의 영향을 받는 관성입자의 침강속도를 측정하고, 정지 상태의 침강속도에 대한 침강속도의 증가비율과 난류 인자의연관성에 대해 조사하였다. 실험에 사용된 관성입자는 비중 1.35, 직경 300 ㎛에서 2000 ㎛까지의 구형 플라스틱(PE; polyethylene) 입자이며, 해당 입자들의 침강속도는 PTV(particle tracking velocimetry) 방식을 통해 측정하였다. 그리고 PIV(particle image velocimetry) 기법을 통해, 개수로 흐름의 난류 에너지 소산율(energy dissipation rate, ϵ)과 그에 따른 Kolomogorov 길이 스케일을 측정하였다. 실험 결과, 모든 직경 조건에서 플라스틱 입자는 난류 흐름에서의 침강속도가 정지 수체에서의 침강속도보다 빠름을 보였으며, 그 비율은 입자 직경이 난류의 길이 스케일과 유사하거나 작아질 때 큰 폭으로 증가하는 것을 확인하였다. 또한 유체 내에서의 관성입자의 거동에 대한 이론식과 비교하여 관성입자의 침강에 미치는 여러 힘들의 상대적 관계를 파악하였다. 본 연구의 결과는 자연 수체에서 미세플라스틱의 거동을 이해하는데 도움이 될 것으로 기대된다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.855-861
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• 1989

An inertia redistribution technique for liberalizing and reducing the complexity of manipulator dynamics with a parallel drive mechanism is presented in this paper. The dynamic design method is based on eliminating nonlinear terms, such as Coriolis, centrifugal and gravity torque in the kinetic and the potential energy of a manipulator. A set of design criteria regarding the inertia properties of links is derived. The resulting manipulator dynamics can be greatly simplified for each robot. This paper particularly presents that it is possible to completely linearize the manipulator dynamics with a parallel drive mechanism.

• Nuclear industry
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• v.14 no.8 s.138
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• pp.26-31
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• 1994

• Nuclear industry
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• v.14 no.10 s.140
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• pp.54-61
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• 1994

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.521-526
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• 2016

This paper suggests a new design that makes use of rotary inertia that can allow autonomous movement of an autonomous colonoscope robot in the colon of a patient as a locomotive mechanism. As commercial colonoscopy causes a lengthy time of pain and discomfort to the patients when colonoscopy patients are reluctant to receive surgery, there is a tendency to avoid the test in the early diagnosis of colorectal cancer. To solve this problem, research has been conducted on the next generation of robotic colonoscopes that can reduce the discomfort and pain by moving autonomously within the colon of the patients. In the driving mechanism utilizing the rotational inertia, a flywheel is driven by a motor to store energy and produce rotational inertia. By the energy stored and released by the flywheel, the stick phenomenon that occurs when the robot is running in the intestine can be overcome effectively. To do this, a controller that can control the velocity of the flywheel and is robust to high frequency noise was designed and implemented. The driving mechanism using the rotational inertia presented here showed that the structure is also effective and the experiment can be run easily compared to another mechanism.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.23-30
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• 2009

Crash cushions are protective devices that prevent errant vehicles from impacting on fixed objects. This function is accomplished by gradually decelerating a vehicle to a safe stop in a relatively short distance. Commonly used crash cushions generally employ one of two concepts to accomplish this function. The first concept involves the absorption of the kinetic energy of a moving vehicle by crushable or plastically deformable materials and the other one involves the transfer of the momentum of a moving vehicle to an expendable mass of material located in the vehicle's path. Crash cushions using the first concept are generally referred to as compression crash cushions and crash cushions using the other concept are generally referred to as inertial crash cushion. The objective of this research is the development of a compression-type crash cushion by employing the two concepts simultaneously. To minimize the number of full-scale crash tests for the development of the crash cushion, preliminary design guide considering inertial and frictional energy absorption was constructed and computer simulation was performed. LS-DYNA program, which is most widely used to analyze roadside safety features, was used for the computer simulation. The developed crash cushion satisfied the safety evaluation criteria for various impact conditions of CC2 performance level in the Korean design guide.