• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.2
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• pp.136-144
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• 2014

The existing conventional motion controller does not perform well in the presence of nonlinear properties, uncertain factors, and servo lag phenomena of industrial actuators. Hence, a feasible and effective fuzzy self-tuning proportional integral derivative (PID) and feed-forward control scheme is introduced to overcome these problems. In this design, a fuzzy tuner is used to tune the PID parameters resulting in the rejection of the disturbance, which achieves better performance. Then, both velocity and acceleration feed-forward units are added to considerably reduce the tracking error due to servo lag. To verify the capability and effectiveness of the proposed control scheme, the hardware configuration includes digital signal processing (DSP) which plays the main role, dual-port RAM (DPRAM) to guarantee rapid and reliable communication with the host, field-programmable gate array (FPGA) to handle the task of the address decoder and receive the feed-back encoder signal, and several peripheral logic circuits. The results from the experiments show that the proposed motion controller has a smooth profile, with high tracking precision and real-time performance, which are applicable in various manufacturing fields.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.27-33
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• 2004

Electro-theological fluid is recently used for the micro polishing of 3-dimensional micro-aspherical lens. It's also used for polishing small area defects on the wide flat wafer. Since ER fluid shows a behavior of viscosity changing under certain electric fields. micro polishing efficiency may be enhanced for certain cases. In this paper, a perfluorinated carbonyl fluoride oil based ER fluids was used to improve surface polishing rate and submicron-scale accuracy. As the polishing electrodes, micro size cylindrical tools had been used for maximizing the electric field. An experimental device, which was applied for micro polishing a number of wafers of 4inches in size and other workpiece. was made on a precision polishing system. It consisted of a steel electrode. a wafer fixture. l0㎃ current and DC 5㎸ power supply unit, and a controller unit. From the Experiments. the ER fluid is applicable for micro polishing of small parts.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.611-613
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• 2000

Rotor eccentricity exists extensively in BLDC motors because of manufacturing imprecision or bearing defects. In this paper, magnetic fields of a BLDC motor with static rotor eccentricity are analyzed by the time- stepping finite element method. Torque ripple, cogging torque, winding current, counter-em! and unbalanced magnetic force characteristics are obtained. These results are compared with those of a non-eccentric BLDC motor.

• International journal of advanced smart convergence
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• v.4 no.2
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• pp.124-130
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• 2015

Infinite competition on ICT industries is starting again. The basis of competence over global dominance will be human resource, a global ecosystem for products and national agenda for science and technology, etc.. This paper presents the six solution for the Global Competitiveness and Coexistence of Korean ICT Industries. Korea should nurture the brand of "World Best Korean ICT Forever" to secure technical competency of ICT related fields in global market. All ICT technologies should be aligned to global standard and market demand from beginning and the ecosystem around product needs to be established. System framework for utilizing the resource of core SW experts must be established. Through global partnership with China as manufacturing base for Korea-developed products, technical competency can be maintained including product planning. Security measure for technical assets is mandatory. Finally, core technology that will drive the future of ICT industries in Korea should be regarded as core subjects.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.230-237
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• 2022

A technology that allows users to feel the elasticity of fabric through force feedback in the fashion and textile fields is very helpful to related manufacturing and sales areas. Currently bundle of fabrics, so called Swatch, is the only available way for the designer, manufacturer and the end-user to feel the fabrics. Images and video clips provide only visual characteristics, hence touch and stiffness are also very important characteristics to check beforehand. A study is conducted on a haptic device, which estimates the amount of change in the length of the virtual fabric and generates resistive force so that the user could feel the fabric stiffness. Since cables that can only transmit the tensile force are used, a force realization method is proposed, and it is verified numerically and experimentally.

• 연구논문집
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• s.25
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• pp.91-98
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• 1995

Recently, improving the energy efficiency of a pneumatic system and reducing the consumption of compressed air were a concern of scholars at domestic and abroad. The using fields of a pneumatic system are widely used in factory automation of manufacturing line, chemical factories with explosiveness danger and petroleum industries etc. In particular, pneumatic cylinder is applied to feeding work of workpiece. jig tools and press mechanism, reciprocation and rotary motion with rack and pinion. In this study, the experimental apparatus consisted to pneumatic cylinder, dual supply pressure regulator and solenoid valve. The dual supply pressure regulator connected to outlet port of solenoid valve. The supply pressure($4.5kg_f/cm^2$) of compressed air goes into the rodless chamber 1 to drive the piston rod forward which is named working stage. The supply pressure ($2kg_f/cm^2$) of compressed air goes into the rod chamber 2 to drive the piston rod backward which is named no-working stage. Accordingly, the research results of this study can be obtained to Energy-Saving Effects of the compressed air about 35%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1C
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• pp.17-23
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• 2012

RFID(Radio Frequency IDentification) is now being applied in the lots of fields as an alternative of barcode system. However, it is restricted within product manufacturing, sales, and delivery parts. In this paper, research results regarding an actual progress of an RFID-based system and its effect are described. In addition, this paper confirms that the RFID-based process of manufacture gives much better return of investment than the barcode-based one. Therefore, the results of this paper are highly expected to contribute to make many people, who might hesitate to replace the barcode and apply RFID system to the process of manufacture, a positive decision.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.494-497
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• 2002

The purpose of this study is to establish a prototype system for effective construction safety management. The research method involves comparison and adaptation into construction of quality and environment management systems in foreign and domestic manufacturing fields. The results of this study we as follows: The suggested model for construction safety management can be used effectively for the parties such as employer, employees, stakeholders, and the public especially through the application of performance measuring and reporting system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.639-640
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• 2006

Many companies in mechanical engineering fields have accumulated information of design and manufacturing. The Enterprise Resource Planning (ERP) and Product Data Management (PDM) systems help information gathering and data managing. However, these systems are not flexible to support suitable functionality for specific product because these systems deal with entire enterprise resources. To cope with this issue, a web-based design support system was constructed for the design process of automotive steel pulley. This system provided 1) search service for part design with key word and clustering map, and 2) estimation service of maximum stress. These services reduced design time by reducing iterative jobs with Computer Aided Design (CAD) and Computer Aided Engineering (CAE) for stress analysis, and by enhancing search for existing data of steel pulley.

• Journal of the Korea Society for Simulation
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• v.14 no.3
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• pp.91-100
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• 2005

Grid computing is widely applicable to various fields of industry including process control and manufacturing, military command and control, transportation management, and so on. In a viewpoint of application area, grid computing can be classified to three aspects that are computational grid, data grid and access grid. This paper focuses on computational grid which handles complex and large-scale computing problems. Computational grid is characterized by system dynamics which handles a variety of processors and jobs on continuous time. To solve problems of system complexity and reliability due to complex system dynamics, computational grid needs scheduling policies that allocate various jobs to proper processors and decide processing orders of allocated jobs. This paper proposes a service prediction-based job scheduling model and present its scheduling algorithm that is applicable for computational grid. The service prediction-based job scheduling model can minimize overall system execution time since the model predicts the next processing time of each processing component and distributes a job to a processing component with minimum processing time. This paper implements the job scheduling model on the DEVS modeling and simulation environment and evaluates its efficiency and reliability. Empirical results, which are compared to conventional scheduling policies, show the usefulness of service prediction-based job scheduling.