• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1497-1502
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• 2012

To manufacture a robot hand that essentially mimics the functions of a human hand, it is necessary to develop flexible actuators and sensors. In this study, we propose the design, manufacture, and performance verification of flexible actuators and sensors based on Electro Active Polymer (EAP). EAP is fabricated as a type of film, and it moves with changes in the voltage because of contraction and expansion in the polymer film. Furthermore, if a force is applied to an EAP film, its thickness and effective area change, and therefore, the capacitance also changes. By using this mechanism, we produce capacitive actuators and sensors. In this study, we propose an EAP-based capacitive sensor and evaluate its use as a robot hand sensor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.694-699
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• 2002

As the demand for slim laptops requires ion'-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method far anti-vibration mechanism with respect to the existing servo gain plot. This method verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.608-615
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• 2012

In this study, we analyzed the system impedance of Unmanned Aerial Vehicle avionics bay and Environmental Control System(ECS), and estimated the proper air flow rate to be supplied avionics equipments. As the result of estimation, we evaluated the performance of ECS after analysing the flow balance rate and the air flow rate about each outlet port, and simultaneously decided the flow balance rate after evaluating the thermal substantiality by the thermal analysis of avionics bay. In order to verify the property of analysis result, we conducted the flow balance test using the actual avionics equipments and finally deduced the flow rate to be met system requirements of avionics equipments. Also, as the analysis results, we verified the satisfaction of system requirements at midium altitude condition and proved the performance characteristics of an Environmental Control System(ECS).

• Journal of Korean Society of Water and Wastewater
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• v.28 no.6
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• pp.735-745
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• 2014

This paper presents PKES(PuKyung -Excel based Simulator) for WWTPs(wastewater treatment plants) by using MS Excel and VBA(Visual Basic for Application). PKES is a user-friendly simulator for the design and optimization of the whole plant including biological and physico-chemical processes for the wastewater and sludge treatment. PKES calculates the performance under steady or dynamic state and allows changing the mathematical model by the user. Mathematical model implemented in PKES is a improved integration model based on ASM2d and ADM1 for simulation of AS(activated sludge) and AD(anaerobic digestion). Gaseous components of $N_2$, $N_2O$, $CO_2$ and $CH_4$ are added for estimation of GHGs(greenhouse gases) emission. The simulation results for comparison between PKES and Aquasim(EAWAG) showed about the same effluent concentrations. As a result of verification using by measured data of BOD, TSS, TN and TP for 2 years of operation, calculated effluent concentrations were similar to measured effluent concentrations. The values of average RMSE(root mean square error) were 1.9, 0.8, 1.6 and 0.2 mg/L for BOD, TSS, TN and TP, respectively. Total GHGs emission of WWTP calculated by PKES was 138.5 ton-$CO_2$/day and GHGs emissions of $N_2O$, $CO_2$ and $CH_4$ were calculated at 21.7, 28.9 and 87.9 ton-$CO_2$/day, respectively. GHGs emission of activated sludge was 32.5 % and that of anaerobic digestion was 67.5 %.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.723-728
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• 2011

Since the performance of a vacuum circuit breaker (VCB) mainly depends on the spring operating mechanism, an analysis of the spring operating mechanism is required in order to improve the design of a VCB. In this study, the static stiffness of the spring was determined by using a material testing machine, and the test results were used to model the spring through computer simulation. The multi-body dynamic model of the spring was established by using the RecurDyn program. The dynamic model was verified by comparing the results of stem displacements and rotating angles of the brake shaft obtained from the simulation and from the experiments. After verification of the dynamic model of VCB, the cam profile of the VCB was optimized through multi-body dynamics simulation in order to improve the performance of the closing mechanism.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1579-1584
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• 2011

This paper discusses an energy system that can convert wave energy into electrical energy. This wave energy generation system is movable and has 12 arms and one generator. A multibody dynamic model for this system is established by using kinematic constraints. A gear mechanism, several kinematic constraints, and force elements are included in the model. Wave forces are obtained numerically from the time domain formulation based on the Morison equation. The MSC/ADAMS program is employed to carry out dynamic analysis of the wave energy generation system. The dynamic behavior responses of this system are analyzed for design verification. According to the results of the dynamic analysis, the yaw motion is relatively stable and kinetic energy sufficient to generate electrical energy is obtained when the wave height exceeds 1m.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.5
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• pp.497-504
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• 2012

The mobile harbor is a new innovative system that delivers containers from a containership to a harbor without good infrastructure. A crane is installed on the deck of the mobile harbor and transfers the containers. The structure of the crane is influenced by the inertia force that occurs from a moving support. Thus an accurate safety verification considering the moving support is required. Lightweight of the crane structure is also significant in the design for low production cost and efficient operation. Dynamic response optimization can be exploited to achieve these two requirements. Equivalent static loads method is employed for dynamic response optimization of the crane. The equivalent static loads method transforms dynamic loads to equivalent static loads, and static response structural optimization with the transformed equivalent static loads are solved. The process proceeds in a cyclic manner. A new method is proposed to consider the moving supports and the structure of the mobile harbor is optimized using the proposed method.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.159.2-159.2
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• 2011

Hyundai Heavy Industries has developed a tidal current energy converter utilizing the accumulated technology as the world largest constructor for ship and offshore structures. The model has two sets of turbines in both ends in order to utilize the bi-directional current flows in flood and ebb tide. The torque produced by turbine in tidal current is directly delivered to generator along the horizontal axis, in which the turbine, gear, generator, gear and turbine are connected successively. The manufactured model for field test has the turbine diameter of 5 meters to produce the maximum power of 500kW at maximum current speed of 5m/s. The technical verification of tidal power converter was performed by means of small scale model test in towing tank as well as field test at the Strait of Uldolmok located in Jindo of Jeollanamdo province. Field test was performed by mounting the tidal current converter on the SEP(Self Elevating Platform) which could lower the 4 vertical legs on the seabed and could elevate platform over the water surface using the hydraulic power for itself. The field test performed for a month shows that power output is similar or larger compared with the expected one in design stage. This paper presents the development of tidal current energy converter and real sea field test by Hyundai Heavy Industries. This project has finished successfully and provided the technical advance toward commercial services for tidal current power generation in the south-west region in Korea.

• Journal of Sensor Science and Technology
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• v.12 no.4
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• pp.170-175
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• 2003

The korean high speed train(350km/h), composed of 7cars that are 2 power cars, 2 motorized car and 3 trailer cars, has been developed and is under on-line test. To verify the design requirements about the functions and traction performances of this train, KRRI(Korea Railroad Research Institute) decided to evaluate traction performances of the train during on-line test. For this purpose, such as torque, velocity, voltage and current, must be measured. KRRI has developed the measurement system that can be measured vast and various signals effectively. In this paper, we introduce traction performances of korean high speed train. The traction measurement items are focused on the verification of motor block performances. Motor block are consist of 2 motor. For this test, we verified traction performances of korean high speed train.

• Journal of Internet Computing and Services
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• v.19 no.1
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• pp.19-26
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• 2018

Social issues for environmental pollution are continuously increasing globally. Especially, Users require services to measure environmental factors in indoor and outdoor and manage related data effectively and conveniently. According to this demand, sensors that can measure environmental factors in indoor and outdoor have been developed. However, since one sensor is composed of independent module, the interface of output data from each sensor is different. To solve the problem, we propose a customized protocol for low-power short-range wireless communication between smartphone using Bluetooth and All-in-One sensor device board and analyze the performance of the proposed customized protocol by developing program for performance verification of interface with user smartphone through Bluetooth. In addition, we implement a smartphone application using proposed protocol.