• Journal of Drive and Control
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• v.13 no.1
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• pp.1-9
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• 2016

Nowadays automatic transmission equipped vehicles prevail in construction and agricultural equipment due to their convenience in driving and operation. Though domestic vehicle manufacturers install imported electronic controlled transmissions at present, overseas products will be replaced by domestic ones in the near future owing to development efforts over the past 10 years. For passenger cars, there are many kinds of shift control algorithms that enhance the shift quality such as feedback and learning control. However, since shift control technologies for heavy duty vehicles are not highly developed, it is possible to improve the shift quality with an organized control method. A feedback control algorithm for neutral-into-gear shift, which is enabled during the inertia phase for the master clutch slip speed to track the slip speed reference, is proposed based on the power transmission structure of TH100. The performance of the feedback shift control is verified by a vehicle test which is implemented with firmware embedded TCU. As the master clutch engages along the predetermined speed trajectory, it can be concluded that the shift quality can be managed by a shift time control parameter. By extending the proposed feedback algorithm for neutral-into-gear shift to gear change and shuttle shift, it is expected that the quality of the shift can be improved.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.19-26
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• 2021

In fine-particle injection processing, hard fine particles, such as silicon carbide or aluminum oxide, are injected - using high-pressure air, and a small amount of material is removed by applying an impact to the workpiece by spraying at high speeds. In this study, a two-axis stage device capable of sequence control was developed to spray various shapes, such as circles and squares, on the surface during the micro-particle jetting process to understand the surface-shape micro-particle-processing characteristics. In the experimental device, two stepper motors were used for the linear movement of the two degree-of-freedom mechanism. The signal output from the microcontroller is - converted into a signal with a current sufficient to drive the stepper motor. The stepper motor rotates precisely in synchronization with the pulse-signal input from the outside, eliminating the need for a separate rotation-angle sensor. The major factors of the processing conditions are fine particles (silicon carbide, aluminum oxide), injection pressure, nozzle diameter, feed rate, and number of injection cycles. They were identified using the ANOVA technique on the design of the experimental method. Based on this, the surface roughness of the spraying surface, surface depth of the spraying surface, and radius of the corner of the spraying surface were measured, and depending on the characteristics, the required spraying conditions were studied.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.218-223
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• 2019

To prevent the low heating effect of heating system caused by the high sheet resistance of CVD graphene, multi-layered graphene was laminated to implement a Transparent plane heating system with good optical properties of low-resistance. Low-resistance plane heating system implemented by $300{\times}400{\times}5mm$ heating plane laminated multi-layered CVD graphene film and PWM control system to drive efficient power. A plane resistance value of $85.5{\Omega}/sq$ was measured on average for 4-layer CVD graphene film used as a heating plane. Thus, the transfer by thermal film as the method of implementing low-resistance CVD graphene is reasonable. The experimental results of heat test show that an average heat-rise rate in low-resistance, transperent plane heating system using CVD graphene is $10^{\circ}C/min$ and has an optical transmittance rate of 86.44%. Therefore, the proposed heating system is applicable to large window glass and vehicle heating window-shild-glass.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.661-667
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• 2018

Electric vehicles are taken a long time to charge and are restricted driving where charging infrastructure was not sufficiently constructed. The vehicle developed to solve these problems is a plug-in hybrid vehicle. It is possible to drive a certain distance by using electric motor and when the battery runs out, it operate the engine. Plug-in hybrid vehicle have a complicated structure and a lot of parts comparing a general vehicle because the electric parts and the internal combustion engine are installed together. Therefore, as the aging (mileage) of the plug-in hybrid vehicle, the influence which change of fuel consumption is expected to be larger than a general vehicle, but an experimental data are lacking. In this paper, we cumulate a mileage of the plug-in hybrid vehicle about 15,000 km and measured the fuel economy when the cumulated distance reached within 160 km, 6,500 km, 15,000 km respectively, by using domestic public test method. For measuring fuel economy of the vehicle, CD mode (driving distance on a single charge) which use only motor and the CS mode which operate motor and combustion engine were measured respectively. As a result, the fuel economy slightly increased at cumulated mileage of 6,500 km compared to the 160 km and the fuel economy of 15,000 km was similar to 160 km.

• Fire Science and Engineering
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• v.33 no.1
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• pp.99-104
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• 2019

In a gas system fire extinguishing system, extinguishing agents are usually stored with approximately 280 bar at $21^{\circ}C$ and are released at approximately 8 MPa through the decompression valve and orifice to quickly suppress the fire. When extinguishing agents are discharged, they cause a loud noise (approximately 140 dB), which can damage electronics, such as hard disk drives (HDDs). Therefore, the noise is becoming a serious issue in the gas extinguishing system. The method of the noise reduction by adding an absorbent is most general and in this study, the thickness of the absorbent was as a selected design variable. The noise level at the observation point and the flow characteristics inside the nozzle were numerically calculated and analyzed using the commercial code ANSYS CFX ver. 18.1.

• Journal of Drive and Control
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• v.18 no.1
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• pp.1-8
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• 2021

This paper presents research on methods for the reduction of forklifts' noise level for the increased comfort and safety of its operator. A cooling fan with a high air volume flow rate installed in the forklift acts as an important design parameter which efficiently cools the heat exchanger system, helping to transfer internal heat from the engine room to the outdoors with both transmitted and diffracted opening noises. The cooling fan contributes significantly to both the forklift's emitted sound power and the operator room's noise level, thereby necessitating research on the forklift's reduction of acoustic power level and transmission. A noise analysis for various fan models with a biomimetic design based on eagle-wing geometry was conducted. In addition to the acoustic power generation, the aerodynamic performance of the cooling blade is also strongly influenced by the design of airfoil distribution, thereby requiring optimization. The cooling fans were fabricated and installed in the forklift in order to check the efficacy of the forklift engine's cooling, and the final version of the fan was measured for its ability to lower acoustic power level and cool the engine room. This study explains the aerodynamic and acoustic features of the designed fans with the use of BEM analysis and forklift test results.

• Journal of IKEEE
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• v.25 no.2
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• pp.381-387
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• 2021

As Head-Mounted Displays(HMDs), which are mainly used to maximize realism in games and videos, have experienced increased demand and expanded scope of use in education and training, there is growing interest in methods to enhance the performance of conventional HMDs. In this study, a methodology to utilize Carbon NanoTubes(CNTs) to improve the performance of gate drivers that send control signals to each pixel circuit of the HMD is discussed. This paper proposes a new circuit design method that replaces the transistors constituting the buffer part of the conventional gate driver with transistors incorporating CNTs and compare the performance of the suggested gate drive with that of a gate driver comprising only conventional transistors via simulations. According to the simulation results, by including CNTs in the gate driver, the output voltage can be increased by approximately 0.3V compared to the conventional gate driver high voltage(1.1V) at a speed of 12.5 GHz and the gate width also can be reduced by up to 20 times.

• Journal of Platform Technology
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• v.8 no.1
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• pp.24-32
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• 2020

This paper designed and manufactured a chip mounter based on 3D printer technology that can be used for educational research or sample production to disseminate chip mounter, a core technology of SMT line. A stepper motor with open loop control is used for low cost drive design. The shortcomings of the motor's vibration and disassembly caused by the use of the step motor were compensated by the Micro-Step control method. In the chip mounter experiment, the gerber file was generated on the small chip mounter, printed at the actual size, and the solder cream was printed on the HASL-treated PCB in the same manner as the sample board fabrication. As a result of the experiment, unlike the 2012 micro components, parts such as SOIC and TQFP that require correction are twice as long as the component mounting time, but it can be confirmed that they are mounted relatively accurately. In addition, as a result of repeatedly measuring the error of the initial position 10 times, it was confirmed that a relatively small error of about 0.110mm occurs.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.1
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• pp.29-37
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• 2020

This paper implements a method of extracting an object about a dog through real-time image analysis and classifying dog behaviors from the extracted images. The Darknet YOLO was used to detect dog objects, and the Teachable Machine provided by Google was used to classify behavior patterns from the extracted images. The trained Teachable Machine is saved in Google Drive and can be used by ml5.js implemented on a node.js server. By implementing an interactive web server using a socket.io module on the node.js server, the classified results are transmitted to the user's smart phone or PC in real time so that it can be checked anytime, anywhere.

• Journal of Drive and Control
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• v.19 no.4
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• pp.19-28
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• 2022

This paper introduces an automatic steering system for straight traveling capable of being mounted on drivable agricultural machinery which user can handle it such as a tractor, a transplant, etc. The modular automatic steering device proposed in the paper is composed of RTK GNSS, IMU, HMI, hydraulic valve, and wheel sensor. The path generation method of the automatic steering system is obtained from two location information(latitude and longitude on each point) measured by GNSS in advance. From HMI, a straight path(AB line) can be created by connecting latitude and longitude on each point and the device makes the machine able to follow the path. During traveling along the reference path, it acquires the real time position data every sample time(0.1s), compares the reference with them and calculates the lateral deviation. The values of deviation are used to control the steering angle of the machine using hydraulic valve mounted on the axle of front wheel. In this paper, Pure Pursuit algorithm is applied used in autonomous vehicles frequently. For the analysis of traveling characteristics, field tests were executed about these conditions: velocity of 2, 3, 4km/h which is applied to general agricultural work and ground surface of solid(asphalt) and weak condition(soil) such as farmland. In the case of weak ground state, two experiments were executed about no-load(without work) and load(with work such as plowing). The maximum average deviations were presented 2.44cm, 7.32cm, and 11.34cm during traveling on three ground conditions : asphalt, soil without load and with load(plowing).