• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.4
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• pp.64-69
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• 2009

This paper addresses the simulation methodology of signal integrity and power integrity for mobile display modules. The proposed technique can be applied to analyse a circuit module which consist of connector, FPCB and driver ICs. The recent demand of serial interconnection technology in the mobile display industry needs delicate impedance control of signal and power traces to prohibit system malfunctioning and to reduce electromagnetic field radiation. Based on the S-parameter and Z-parameter analysis, we analyse the correlation between frequency-domain and time-domain measurements. With multi-port macros, signal integrity can be included in power integrity analysis in time domain.

• Journal of Drive and Control
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• v.12 no.4
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• pp.54-59
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• 2015

Due to the tendency to use high speed pneumatic cylinders to improve productivity, cushioning devices are adopted to decelerate the piston motion of pneumatic cylinders to reduce noise, vibration, and impact. This paper presents a comparison of the cushion characteristics of a high speed pneumatic cylinder with a relief valve type cushioning device. The system parameters selected are the damping coefficient, Coulomb friction, heat transfer coefficient, and cracking pressure of the relief valve in the air cushioning device. The integral of the time multiplied square error (ITSE) is used to quantitative measure the cushioning performance to assess the effect of varying these. The cushioning performance achieved good results when the ITSE is a minimum value. In a comparison of the piston displacement and velocity with the variations in system parameters, the heat transfer coefficients are not as significantly affected as the other. Also, the cracking pressure of the relief valve is mainly affected by the pressure and temperature in the cushion chamber.

• Journal of Drive and Control
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• v.15 no.1
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• pp.16-27
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• 2018

Hydraulic torque load simulator is essential to test and qualify the performance of various angle control systems. Typically a flapper-type second stage servovalve is applied to the load simulator, but here the direct drive servovalve, which is a kind of one-stage valve and affected by the large flow force, is applied. Since the torque load is applied not to the stationary shaft but to the rotating shaft of the angle control system, the controlled torque of load simulator is not accurate due to the rotating speed of the angle control system. A feedforward compensator is designed and applied to minimize the disturbance-like effect. A mathematical model is derived and linearized to analyze the stability, accuracy and responsiveness of the torque load simulator. The parameter effects of a controller, servovalve, hydraulic motor, rotating spring shaft are analyzed and summarized. The goodness of the linear analysis is verified by the digital computer simulations using both the linear and nonlinear mathematical models.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.12
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• pp.1423-1436
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• 1992

In the paper, a CAT interface supporting multitask is realized. To interface a computer with measuring instruments, a GPIB card is designed and implemented. Controlling and displaying software using OOP and GUI are programmed with C++. A spectrum analyzer and a power meter are chosen as object instrument to be controlled. Total 9 modules are configured to manage the various resources and each module in integrated system. Also in case that several instruments are used, the system is realized to be capable of multitasking to exchange the data mutually. The multitasking is implemented under the time-sharing DOS environment. Thread-based method is used for processing, and Round Robin method for scheduling. Provided proper software modules for other object instruments are integrated, the system can control more measuring instruments simultaneously by the computer. Users can save the time and errors even without expert knowledge.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.12
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• pp.859-866
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• 2006

Grid portal services provide more flexible research environment by overcoming time and space limit of existing application-based grid services. However user's requirements such as user interfaces are not clear during development cycle and changed frequently. Therefore it is necessary to reduce the cost for creating and maintaining user interfaces of grid services. In this paper, we suggest an object-oriented user control model which allows easier development of user interfaces and increases code reusability by abstracting objects from presentation layer of web. In this model, structure of presentation pages can be described more clearly and implementation of actions is simple and easy.

• Journal of Drive and Control
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• v.11 no.1
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• pp.1-7
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• 2014

This paper presents a novel concept of wave energy converter for electric generation from the ocean wave energy. In this paper, a Multi-Point Absorbing Wave Energy Converter, shortened as MPAWEC by using Secondary Control Hydrostatic Transmission (SCHST) was proposed. The power take-off (PTO) system in the proposed MPAWEC includes multi heaving buoys to drive hydraulic pumps placed at different points. The application of SCHST in MPAWEC gives some advantages, such as longevity of hydraulic components; more energy is harvested; the variation of the pressure in the accumulator limited; therefore the accumulator volume is reduced and the output speed is more stable, etc. A PID controller was designed for speed control of the hydraulic motor. The simulation results indicated that the speed of the generator was ensured with the relative error as 0.67%; the efficiency of the proposed system was 71.4%.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.17-22
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• 2014

Recently, the quick heating performance is an important issue in the car because engine power becomes so high. So car makers have been adapted the additional heating devices as like PTC(Positive Temperature Coefficient) heater. And the quick cooling performance is also important issue because its result is used in the IQS(Initial Quality Study). In this paper, control of the HVAC(Heating, Ventilation and Air Conditioning) intake door has been studied for the quick heating and cooling performance. Heating performance is improved $4.0^{\circ}C$ at $-20^{\circ}C$ ambient temperature after 20 minutes. And cooling performance is improved $1.5^{\circ}C$ at $35^{\circ}C$ ambient temperature after 10 minutes. In addition, intake door control system brings on the cost reduction because the flab door can be eliminated. This intake door control system has been adapted to the new developing cars.

• Journal of Drive and Control
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• v.15 no.3
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• pp.43-48
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• 2018

The hydraulic control valve, used in the CPB (cold-pad-Batch) cold dyeing system, passes through a pressurized material that absorbs the dye. The hydraulic control of the hydraulic control panel shall be driven in a uniform and precisely controlled manner, as it interferes directly with the dyschromatism. In this study, an acceleration test model was employed to verify the durability of the hydraulic control of the hydraulic control panel, which was manufactured by the scenic model, and the pre-roll angle was analyzed before the performance of acceleration test. Based on the change in the amount of deformation of the padder roll the durability of the padder roll was analyzed along with verification of the durability of the skin and the rubber coating in contact with the fabric. Furthermore, the accelerated test method used for hydraulic controlled multi-cell padder rolls was verified.

• Journal of Drive and Control
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• v.9 no.4
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• pp.8-13
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• 2012

Recently, researches about the eco-friendly vehicles such as hybrid electric vehicle, fuel cell vehicle and electric vehicle have been actively carried out. The regenerative braking system is a key technology to improve the vehicle energy utilization efficiency because it transforms the kinetic energy to the electric energy through the electric motor. This new braking system requires cooperative control between electric controlled brake and regenerative brake. Therefore, it is necessary to establish fault-diagnosis and fail-safe evaluation criteria to secure reliability of the regenerative braking system. In this paper, the failure types and causes in regenerative braking system were analyzed. The transient behavior characteristics were examined based on fault-diagnosis and fail-safe upon failure of regenerative braking system.

• Journal of Drive and Control
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• v.10 no.2
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• pp.23-29
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• 2013

The excavator is used in a variety of construction environments. There are many kinds of risk like falling rocks or harmful dust. The excavator cabin protects the operator not only from these harmful environments but also provides a comfortable working environment. By the way, the excavator cabin consumes a lot of energy for cabin air conditioner. For this reason, the research is required to reduce energy consumption. This study suggests the air conditioning system for excavator using forced exhaust. First, the forced exhaust system simulated by AMESim tool and surveyed the applicability. Using AMESim simulation, it was investigated the effect of cabin inside temperature by intake flow rate and intake air temperature. The experiment executed using the 1.5 ton excavator and field tested according to the intake flow rate. Finally, verified the applicability on the air conditioning system for excavator using forced exhaust.