• Journal of the Korean Society for Precision Engineering
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• v.24 no.7 s.196
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• pp.90-97
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• 2007

This paper describes the development of 6-axis force/moment sensor considered adult weight far an intelligent foot of humanoid robot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself and control the foot using the forces and moments. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to the foot, which is composed of Fx sensor, Fy sensor, Fz sensor, Mx sensor, My sensor and Mz sensor in a body. Each sensor should get the deferent rated load, because the applied forces and moments to foot in walking are deferent. Therefore, one of the important things in the sensor is to design each sensor with the deferent rated load and the same rated output. In this paper, a 6-axis force/moment sensor (rated load of Fx and Fy are 500Nm and Fz sensor is 1000N, and those of Mx and My are 18Nm, Mz sensor is 8Nm) for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using by ANSYS software (FEM (Finite Element Method) program). Then, a 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• Journal of Internet Computing and Services
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• v.3 no.3
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• pp.87-93
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• 2002

A complex network and a parallel computer are made up of interconnected switching units. The role of a switching unit is to set up a connection between an input port and an output port, according to the routing information. We proposed our switching network with a remodeled architecture is a newly modified Banyan network with eight input and output ports. We have analysed the maximum throughput of the revised switch. Our analyses have shown that under the uniform random traffic load, the FIFO discipline is limited to 70%, The switching system consists of an input control unit, a switch unit and an output control unit. Therefore the result of the analyses shows that the results of the networking simulation with the new switch are feasible and if we adopt the new architecture of the revised model of the Banyan switch, the hardware complexity can be reduced. The FIFO discipline has increased by about 11% when we compare the switching system with the input buffer system. We have designed and verified the switching system in VHDL using Max＋plusII. We also designed our test environment including micro computers, the base station, and the proposed architecture. We proposed a new architecture of the Banyan switch for BISDN networks and parallel computers.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2348-2356
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• 2011

In recent years, many researches for DC power distributed system (PDS) are being preformed and the importance of the DC PDS is more and more emphasized. Furthermore, in the railway system, the DC PDS is used in subway station lighting, facilities, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple parallel loads such as pulsed power load, motor drive system, and constant power loads. Thus, good quality and high reliability for electric power are required and voltage bus conditioner (VBC) may be used the DC PDS. The VBC is a DC/DC converter for mitigation of the bus transients. In this paper, adaptive controller is designed. The simulation results by PSIM are presented for validating the proposed control algorithm.

• Journal of Welding and Joining
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• v.34 no.3
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• pp.1-5
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• 2016

At present, FSW(friction stir welding) process is being considered as an actual way for production of various industrial products. However FSW process involves high temperature and load on the tool during welding. These are make a difference between FSW machine and general machine tools. From this reason, development of FSW machine needs very careful consideration on stiffness of machine structure, spindle and moving axis including machine control system. In this study authors investigate on the trends of technology development of FSW machine in order to share the information for more extension of FSW technology with related researchers and engineers.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.8
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• pp.316-324
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• 1984

In the wound rotor induction motor, the external resistor is usually added to the rotor circuit in order to limit the starting current. In this scheme, whilst the starting current is limited, the available torque is remarkably reduced. In this paper, to improve the starting characteristics the stator current can be maintained constant by adjusting the external resistor. To change the external resistor, teh chopper and the resistor is connected in parallel, and the chopper duty cycle is adjusted by microprocessor. The duty cycle is calculated according to the actual speed of motor by microprocessor look-up table map. In this suggested scheme, the starting characteristics are remarkably improved without over-current. The starting time of this system is reduced by 20-48 Percent compared with fixed extemal resistance system in the same load.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1234-1235
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• 2011

A DC Power Distribution Systems(DC PDS) are widely used in telecommunication system, electric vehicle, aircraft, military system, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple loads such as pulsed power load, motor drive system, and constant power loads. To damp the transients of the DC bus voltage, the Voltage Bus Conditioner(VBC) with the PI compensator is used. In this paper, the validity of the proposed VBC system is verified by PSIM simulation package.

• Journal of Mechanical Science and Technology
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• v.16 no.10
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• pp.1296-1302
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• 2002

A mathematical model for cold rolling and temper rolling process of thin steel strip has been developed using the influence function method. By solving the equations describing roll gap phenomena in a unique procedure and considering more influence factors, the model offers significant improvements in accuracy, robustness and generality of the solution for the thin strip cold and temper rolling conditions. The relationship between the shape of the roll profile and the roll force is also discussed. Calculation results show that any change increasing the roll force may result in or enlarge the central flat region in the deformation zone. Applied to the temper rolling process, the model can well predict not only the rolling load but also the large forward slip. Therefore, the measured forward slip, together with the measured roll force, was used to calibrate the model. The model was installed in tile setup computer of a temper rolling mill to make parallel setup calculations. The calculation results show good agreement with the measured data and the validity and precision of the model are proven.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1495-1498
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• 1987

This paper described the design of register part, ROM and entire digital filter implementation by merging with ALU, control part last year. The register part consists of shift register, parallel load serial output register, multiplexer and selector, and we designed specially the 1024 memory cells ROM and decoder to decode the register data. Also, presented scaling algorithm to prevent the overflow.

• Journal of Drive and Control
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• v.9 no.4
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• pp.26-31
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• 2012

Friction reduction between sliding hydraulic machine components is required to improve efficiency and reliability of hydraulic machineries. It is recently reported that surface texturing on sliding bearing surfaces can reduce the friction force highly. In this paper, numerical analysis is carried out to investigate the effect of dimple numbers and inlet boundary pressures on the lubrication characteristics of a parallel sliding bearing using a commercial computational fluid dynamics (CFD) code, FLUENT. The results show that the pressure distribution, load capacity, dimensionless friction force and leakage with dimple number and their locations, and inlet pressures. The overall lubrication characteristics are highly affected by dimple numbers and boundary pressure. The numerical method adopted and results can be used in design of efficient hydraulic machine components.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.79-84
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• 2010

This paper discusses the control of generator field using dual IGBT PWM regeneration method to target brushless synchronous generator. If one of PWM bridges happens to fault, it transfers automatically and can be in charge of full load. Also it has an advantage of the operation which UPS connected in parallel with PWM bridge can supply power to excitation system in condition of main power loss. This PWM system supplies field current to generator in one quadrature operation, regenerates field coil energy to main power supplier in four quadrature operation. We designed, manufactured and applied the first trial product at J-power plant.