• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.339-347
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• 2007

A hexapod walking robot had been developed for gathering information in the field. The developed robot was $260{\times}260{\times}130$ ($W{\times}L{\times}H$, mm) in size and 14.7 N in weight. The legs had nineteen degrees of freedom. A leg has three rotational joints actuated by small servomotors. Two servomotors placed at ankle and knee played the roles of vertical joint for up and down motions of the leg and the other one placed at coxa played the role of horizontal joint for forward and backward motions. In addition, a servomotor placed at thorax between the front legs and the middle legs played the role of vertical joint for pumping the two front legs to climb stair or inclination. Walking motion of the robot was executed by tripod gait. The robot was controlled by manual remote-controller communicated by an infrared ray. Two controllers were equipped to control the walking of the robot. The sub-controller using PIC microcomputer (Microchips, PIC16F84A) received the 16 bit command signal from the manual remote controller, decoded it to 8bit and transmitted it to the main microcomputer (RENESAS, SH2/7045), which controlled the 19 servomotors using the PWM command signals. Walking speeds were controlled by adjusting the period of command cycle and the stride. Forward walking speed were within 100 cm/min to 300 cm/min. However, experimental walking speed had the error of 4-40 cm/min to compare with the theoretical one, because of slippage of the leg and the circular arc motion of servomotor of coxa.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1383-1388
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• 2015

Proportional integral derivative (PID) control is one of the conventional control strategies. Industrial PID control has many options, tools, and parameters for dealing with the wide spectrum of difficulties and opportunities in manufacturing plants. It has a simple control structure that is easy to understand and relatively easy to tune. Injection mold is warming up to the idea of cycling the tool surface temperature during the molding cycle rather than keeping it constant. This “heating and cooling” process has rapidly gained popularity abroad. However, it has discovered that raising the mold wall temperature above the resin’s glass-transition or crystalline melting temperature during the filling stage is followed by rapid cooling and improved product performance in applications from automotive to packaging to optics. In previous studies, optimization methods were mainly selected on the basis of the subjective experience. Appropriate techniques are necessary to optimize the cooling channels for the injection mold. In this study, a digital signal processor (DSP)-based PID control system is applied to injection molding machines. The main aim of this study is to optimize the control of the proposed structure, including a digital PID control method with a DSP chip in the injection molding machine.

• International Journal of Automotive Technology
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• v.7 no.7
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• pp.785-793
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• 2006

The topic of this study is the control strategy of a mild hybrid electric vehicle (HEV) equipped with a continuously variable transmission (CVT). A brief powertrain and vehicle configuration is introduced followed by the control strategy of the HEV with emphasis on two key parts. One of them is an ideal operating surface (IOS) that operates the CVT powertrain optimally from the viewpoint of the tank-to-wheel efficiency. The other is a charge sustaining energy management to maintain the battery state of charge (SOC) within an appropriate level. The fuel economy simulation results of the HEV over standard driving cycles were compared with those of the baseline vehicle. Depending on the driving cycle, 1.3-20% fuel saving potential is predicted by the mild hybridisation using an integrated starter alternator (ISA). The detailed energy flow analysis shows that the majority of the improvement comes from the idle stop function and the benefits for electrical accessories. Additionally, the differences between the initial and the final SOC are in the range $-1.0{\sim}+3.8%$ in the examined cycle.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.1
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• pp.61-67
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• 1999

An active control for the swing of crane systems is very important for increasing the productivity. This article introduces the control for the position and the swing of a crane using the fuzzy learning method. Because the crane is a multi-variable system, learning is done to control both position and swing of the crane. Also the fuzzy control rules are separately acquired with the loading and unloading situation of the crane for more accurate control. And We designed controller by fuzzy learning method, and then compare fuzzy learning method with LQR. The result of simulations shows that the crane is controlled better than LQR for a very large swing angle of 1 radian within nearly one cycle.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.3
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• pp.31-37
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• 1995

In this paper, we propose a programmable 16 bit DSP architecture using FIFO instruction memory. With this DSP architecture, System structure, BUS structure, instruction set ant and an assembler for system test are developed. The characteristic of this structure is that it simply fetches instructions not from RAM but from FIFO using shift operations. Accordingly, System can be designed regardless of RAM access time. One cycle is enough to execute an instruction, if instruction pipeline is operated. Another merit of this structure is that we can obtain the same effect as instruction pipelining without constructing a complex pipelined controller by decreasing the pipeline number.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.6
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• pp.20-28
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• 2003

This paper presents development of a high speed rotating arc sensor system using a microprocessor based controller with tracking function for a complicate curved fillet welding line, The welding tip connected to the torch body is eccentrically positioned from the centerline of the torch, The area during one rotating cycle is divided into 4 regions of front, rear, right and left in welding direction of the torch tip to determine the horizontal deviation between the welding seam and the torch position. The average value at each region is calculated using the regional current values and a low pass filter incorporated with the moving average method is implemented. The effectiveness of the developed system is proven through the experimental results for several kinds of complicate curved fillet welding lines.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.513-518
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• 2008

In the air-conditioning and refrigeration industry, the efforts to protect the environment have been made. One of them is to use carbon dioxide as an alternative refrigerant, however, several researches have shown that the transcritical heat pump system using $CO_2$ has relatively lower efficiency resulting in a degraded steady-state system performance. Capacity control with fuzzy controller was carried out for $CO_2$ heat pump system. Evaporator secondary fluid outlet temperature was suggested for the control variable of compressor speed modulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1152-1162
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• 2011

In this paper, a single-phase DC-AC inverter using two embedded Z-source converters is proposed. The proposed inverter is composed of two embedded Z-source converters with common DC source and output AC load. The output AC voltage of the inverter is obtained by the difference of output capacitor voltages of each converter. The output voltage of each converter take shape of the asymmetrical AC waveform centering zero voltage. Therefore, the proposed inverter can generate the same output voltage despite low VA rating L-C elements, compared to the conventional inverter using high DC voltage with AC ripple. To verify the validity of the proposed system, the PSIM simulation was achieved under the condition of rapid increase of DC source (110[V]${\rightarrow}$150[V]) and R-load (50[${\Omega}$]${\rightarrow}$300[${\Omega}$]). For controlling the voltage of the inverter system, the one-cycle controller was adopted. As results, the proposed inverter output the constant AC voltage (220[V]rms/60[Hz]) for all conditions. Also, the R-L load and nonlinear diode load were adopted for the proposed inverter loads, and we could know that the its output voltage characteristics were as good as the pure R-load. Finally, the RMS and THD of output AC voltage were examined for the different loads, input DC voltages and reference voltage signals.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.247-252
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• 2007

The container crane is one of the most important equipments at container terminal. If its working time in cycle could be reduced then container terminal efficiency and service level can be increased. So there are many i1forts to reduce working time of container cranes. It means how to design the controller with good performance which has small overshoot and swing motion of container crane. We, in this paper, present a state feedback controller based on LQ theory incorporating a RCGA which means real-coded genetic algorithm RCGA can search state feedback gains under given objective function. A set of simulation works are carried out in order to prove the control effectiveness of the proposed methods.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.51-55
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• 2007

Generally, PLC (Power Line Communication) based home automation devices such as wall switch, walt socket, gas controller, etc, must maintain wake-up status at all time to control other electronic devices and monitor their on/off status whether they are in service or not. In order to reduce the unnecessary energy consumption during the standby mode, the new power-saving PLC 2 ports wall switch has been developed, separating PLC communication part and controller part and introducing sleep mode. In addition, to expand life cycle of PLC product and to reduce the rate of product failure in active mode, the instant controlling method in controlling process is adopted instead of the maintenance controlling method. In comparison to the earlier model, the new 2 ports PLC wall switch has reduced power by 0.95[W] less in standby mode and 3.2[W] less in active mode than the previous one.