• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.397-402
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• 2005

In this paper, to improve the efficiency of welding and user convenience in the shipbuilding industry, a PC-based off-line programming (OLP) technique and the development of a robot transfer unit are presented. The developed OLP system is capable of not only robot motion simulations but also automatic generations of a series of robot programs. The strength of the developed OLP system lies in its flexibility in handling the changes of the welding robot's target objects. Moreover, for a precise transfer of the robot to a desired location, an auxiliary mobile platform named a robot-origin-transfer-unit (ROTU) was developed. To enhance the cornering capability of the platform in a narrow area, the developed ROTU is equipped with 2 steering wheels and 1 driving wheel. Both the OLP and the ROTU were field-tested and their performances were proven successful.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.32-42
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• 2005

In this paper, to improve the efficiency of welding and user convenience in the shipbuilding industry, a PC-based off-line programming (OLP) technique and the development of a robot transfer unit are presented. The developed OLP system is capable of not only robot motion simulations but also automatic generations of a series of robot programs. The strength of the developed OLP system lies in its flexibility in handling the changes of the welding robot's target objects. Moreover, for a precise transfer of the robot to a desired location, an auxiliary mobile platform named a robot-origin-transfer-unit (ROTU) was developed. To enhance the cornering capability of the platform in a narrow area, the developed ROTU is equipped with 2 steering wheels and 1 driving wheel. Both the OLP and the ROTU were field­tested and their performances were proven successful.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.791-796
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• 2012

Small gas turbine engines are used in aircraft as an auxiliary power unit (APU) to supply compressed air to start the main engine and for emergency electricity. When an aircraft is operating in an environment in which sand and dust is present in the ambient air, the engines as well as the APU ingest the sand and dust. This causes erosion of the engine and a degradation in its performance. The present study investigated the effect of sand and dust ingestion on small gas turbine engines. The concentration of sand and dust was $4.4{\times}10^{-5}kg$ per unit kg of air, which follows the specification in MIL-E-8593. The test was conducted for 10 h, and the engine performance before and after the test was compared. In addition, a tear-down inspection was conducted to examine the erosion patterns of sub-components such as the impeller and turbine wheel.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.440-445
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• 2011

This paper presents a new regenerative brake system of electric vehicles that employs a continuous variable transmission(CVT) and a flywheel. The developed device has advantages over existing regenerative brakes from a standpoint of reliability and versatility in actual driving conditions. The system consists of a CVT, two wheels, a flywheel, a coupling and auxiliary powertrain components. The CVT is designed as a combination of two cones and a roller, which causes the velocity difference between the wheel and the flywheel. The power flow of the flywheel system is controlled by the CVT roller and the coupling through step motors. A prototype has been developed and then its performance has been investigated for various operating conditions. Results show that the storage efficiency of the flywheel is much affected by the vehicle's velocity and it is reduced below 20% for high speed, as compared to the 25% efficiency for an ideal condition. The CVT is a primary factor for lowering the flywheel efficiencies due to large friction and slipping between the cone and the roller.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.233-244
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• 2020

A double-parked car is the one that is parked in a crowded parking lot with its transmission gear in neutral position and its auxiliary brake released. A double-parked car can be moved by pushing it but doing so is very difficult and dangerous. In a previous study, we proposed an omni-directional mobile robot for moving a double parked car. In that study we adopted Mecanum wheels. Even though the proposed robot showed successful results, it has some drawbacks such as dependency on a load condition, complexity in control, inefficiency in power use, etc. To overcome those drawbacks, we propose a differential drive robot with ordinary two tire wheels. The proposed robot consists of two parts, one is a wheel part and the other is a body part. By selectively connecting or disconnecting those two parts with the aid of an electric brake, the proposed robot is able to have omni-directional mobility.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.7
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• pp.935-941
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• 2012

This paper describes a study of conventional electrical rig and simulated application of Flywheel Energy Storage system on the power system of the offshore plants with dynamic positioning system with the following aims: improve fuel consumption on engines, prevent blackout and mitigate voltage sags due to pulsed load and fault. Fuel consumption has been analyzed for the generators of the typical drilling rigs compared with the power plant with Flywheel Storage Unit which has an important aid in avoiding power interruption during DP (Dynamic Positioning) operation. The FES (Fly wheel Energy storage System) releases energy very quickly and efficiently to ensure continuity of the power supply to essential consumers such as auxiliary machinery and thrusters upon main power failure. It will run until the standby diesel generator can start and supply the electric power to the facilities to keep the vessel in correct position under DP operation. The proposed backup method to utilize the quick and large energy storage Flywheel system can be optimized in any power system design on offshore plant.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.175-180
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• 2015

Worldwide, studies on intelligent vehicles for the convenience of drivers have been actively conducted as the number of cars has increased. However, vehicle convenience enabled by buttons lowers the concentration on driving and hence poses as a huge threat to the safety of the driver. The use of one of the convenient features, impaired driving auxiliary equipment, is limited because of its complex usage, and this device also hinders the front view of the driver. This paper proposes a vehicle-control device for controlling the convenient features as well as changes in speed and direction using gestures and motions of the driver. This device consists of an ultrasonic sensor for recognizing movement, an arduino for accepting signal control functions and servo and DC motors apply to various vehicle parts. Firstly, the vehicle-control device was designed using a 3D CAD program known as Solid-works based on the size of the steering wheel. Then, through simulations, a suitable length for minimizing the absorbent between ultrasonic sensors was confirmed using a program known as COMSOL Multiphysics. Finally, simulation results were verified through experiments, and the optimal size of the device was identified through the number of errors.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.154-164
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• 2011

This study was conducted to develop the semi-crawler type mini-forwarder that can be operated comfortable small-scale logging operation in the steep terrain and also used at a variety of operations such as the civil work in erosion control and forest-road. Considering the minimum turning radius and the width of forest operation road, the total length, width and loading capacity of the semi-crawler type mini-forwarder is 5,750 mm, 1,900 mm and $2.5m^{3}$, respectively. The maximum engine power is 96ps at 3600 rpm. Selected hydraulic pumps are consists of two main pumps and two sub-main pumps. Main hydraulic pumps are utilized to running motor of the front wheel and rear crawler. Sub-main pumps are utilized to the actuation parts such as steering, crane, out-rigger and dump cylinder. The transmission was adapted as the HST (Hydro-Static Transmission) system. The driving parts are designed and manufactured as the front wheel type and the rear crawler type. The steering type was manufactured as the ackerman type. Driving control parts type was designed and manufactured as driver's seat type of normal cars. It is also attached on auxiliary equipments such as winch, log grapple and out-rigger. The traveling speed of the semi-crawler type mini-forwarder in forest road was 5.3 km/hr to 7.7 km/hr.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.10a
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• pp.111-114
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• 1991

The KMRR 4-wheel crane which has a span of 30.6m long shall be designed to maintain its structural integrity during and after seismic shocks. Horizontal and vertical FRS for OBE and SSE conditions at the crane support are after seismic shock. Horizontal and vertical FRS for analysis are 4% for OBE and 7% for SSE. The crane consists of girder, saddle main and auxiliary trolley, and necessaries. They are modeled as beam elements and lumped masses for the following 4 cases ; trolley at center of the crane with and without the rated load, trolley at end with and without the rated load. The static analysis as well as the linear dynamic analysis including frequency and response spectrum analysis are performed for the seismic qualification of the crane using the Finite Element Method. For the simplicity of the analysis, the decoupling criteria are considered for the crane rope and the crane supporting beams. The main sections of the crane are stiffened until the calculated stresses satisfy the allowable limits. The seismic resultant loads are used to design the seismic restraints of the saddle and the trolley to protect the clue from the seismic uplifting loads the study results have show that the seismic design of the KMRR crane is governed by the OBE condition. not by the SSE condition. This paper briefly describes the analysis procedure used in the seismic design of the KMRR crane, and summarizes the analysis results.

• Journal of Industrial Convergence
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• v.17 no.4
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• pp.125-129
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• 2019

With the growing number of people using bicycle, the number of bicycle accidents also has been increasing. It is said that bicycle accident can be reduced up to 11%~44% when riding a bicycle if LED light is used. The headlight of the bicycle makes exposure effect to the opposite side of bike rider while taillight makes exposure effect to the rear bike rider for improving safety. Bicycle safety device capable of displaying a change of direction by LED is implemented in this study in response to control button signal. This signal makes LED light which is installed in pedal and wheel of bicycle as a module type emitting or flickering during the fixed hour. Bicycle auxiliary device in pedal which is able to improve safety using LED when bikers are riding a bike at night is developed in this study. Bicycle safety device applying wireless communication technology will be expected alternative technology in the future to solve a social problem such as energy, environment, and safety.