• Journal of the Ergonomics Society of Korea
• /
• v.27 no.1
• /
• pp.9-19
• /
• 2008

Work-related musculoskeletal hazards in a paper-making industry were examined to explore ergonomic interventions in a participatory approach for mitigating the hazards. Manual tasks occurred in this paper-making industry were quite different with ordinary assembly industry where individual workers perform certain specified tasks repetitively. Workers used to perform varieties of team-based irregular manual tasks to interact with the facilities. Among 96 manual jobs investigated, 44 potential hazardous jobs were screened during basic investigation phase and finally 16 hazardous jobs were identified by the detailed analysis phase. The major hazardous factors were awkward postures and excessive weights. Possible ways of intervention were developed, reviewed and proposed by an ergonomics team comprised of staffs and engineers from various departments and ergonomics specialist from outside the company. The proposed intervention ideas were evaluated and modified by the workers and union representatives in terms of usability and comfort. Implemented interventions including mechanization, automation, and improvement of tools and equipments provided fairly promising results.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.1
• /
• pp.131-138
• /
• 2001

The performance analysis of an electronic equipment test is very complicate due to the variety o vehicles. In this study, automatic design system for the electronic equipment test has been carried out using the standard load patterns. For the test, standard signal patterns for each item are modeled. The test items can be decided by the user by means of these patterns. Also, engineering software modules are developed and proved to be very efficient for analyzing the test results statistically. Experiments are performed for the test system in the vehicle assembly line. By analyzing the test results, it is found that bad samples can be detected without failure. Also, the engineering software modules provide an analytical tool for the automation of the test process.

• Journal of Korean Institute of Industrial Engineers
• /
• v.36 no.4
• /
• pp.243-247
• /
• 2010

Every products, which made by mass production, is not identical in their size but have variations in some intervals specified by tolerance dimensions. Tolerances play major role in standardization of part and its quality, and also make a huge impact on manufacturing cost. The optimal condition for tolerances is giving the values as loose as possible for low production cost while satisfying quality specification, which usually demand tight control of tolerances. Tolerance analysis is necessary to get an optimal solution for this conflict situation. This paper have studied tolerance analysis for universal joint assembly of vehicle steering system and tried to find useful results of the study for product design and quality control.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1995.04a
• /
• pp.306-315
• /
• 1995

This paper presents a bin picking method using a slit beam laser in which a robot recognizes all of the unoccluded objects from the top of jumbled objects, and picks them up one by one. Once those unoccluded objects are removed, newly developed unoccluded objects underneath are recognized and the same process is continued until the bin gets empty. To recognize unoccluded objects, a new algorithm to link edges on slices which are generated by the orthogonally mounted laser on the xy table is proposed. The edges on slices are partitioned and classified using convex and concave function with a distance parameter. The edge types on the neighborhood slices are compared, then the hamming distances among identical kinds of edges are extracted as the features of fuzzy membership function. The sugeno fuzzy integration about features is used to determine linked edges. Finally, the pick-up sequence based on MaxMin theory is determined to cause minimal disturbance to the pile. This proposed method may provide a solution to the automation of part handling in manufacturing environments such as in punch press operation or part assembly.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2414-2417
• /
• 2005

Compact Camera Module(CCM) is widely used in PDA, Celluar phone and PC web camera. With the greatly increasing use for mobile applications, there has been a considerable demands for high speed production of CCM. The major burden of production of CCM is assembly of lens module onto CCD or CMOS packaged circuit board. After module is assembled, the CCM is inspected. In this paper, we developed the image capture board for CCM and the imaging processing algorithm to inspect the defects in captured image of assembled CCMs. The performances of the developed inspection system and its algorithm are tested on samples of 10000 CCMs. Experimental results reveal that the proposed system can focus the lens of CCM within 5s and we can recognize various types of defect of CCM modules with good accuracy and high speed.

• International Journal of Control, Automation, and Systems
• /
• v.2 no.3
• /
• pp.390-397
• /
• 2004

This paper presents the design and testing of a multi-channel vibrotactile display. It is composed of a cylindrical handle with four embedded vibrating elements driven by piezoelectric beams. Vibrations are transmitted to the hands through arrays of pins. The device was tested in sensory substitution for conveying force information during a teleoperated peg insertion. Results show that the device is effective in reducing peak forces during the insertion task.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.12
• /
• pp.19-29
• /
• 1995

The basic technology for a production system represented by design, machining, assembly, and inspection, is machining technology such as CNC machine tools. etc. Direct Numerical Control, that effeciently manages NC programs is developing into Distributed Numerical Control that increases the utilization of the machining cell. It has the ability of monitoring and control, in real time, for CNC and periperial equipment. In this study, we develop a Distributed Numerical Control system that has real time and multitasking operation capability for the machining cell with various CNC's. With the consideration of economy, generalization and extension, the system is interfaced with CNC machine tools and periperial device using RS-485 network and RS-232C communication methods.

• Journal of Mechanical Science and Technology
• /
• v.14 no.7
• /
• pp.782-788
• /
• 2000

In this paper, we present a new approach to visual feedback control using image-based visual servoing with stereo vision. In order to control the position and orientation of a robot with respect to an object, a new technique is proposed using binocular stereo vision. The stereo vision enables us to calculate an exact image Jacobian not only around a desired location but also at other locations. The suggested technique can guide a robot manipulator to the desired location without providing a priori knowledge such as the relative distance to the desired location or the model of an object even when the initial positioning error is large. This paper describes a model of stereo vision and how to generate feedback commands. The performance of the proposed visual servoing system is illustrated by experimental results and compared with conventional control methods for an assembly robot.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.733-737
• /
• 1996

This paper presents a method to measure tile position and orientation of a prismatic polyhedral object (of unknown width, length, height, and number of vertices) using machine vision. The width, length, and origin of workplace where an object is lying are defined as Preliminary operation. The edges of an object are detected from captured image using least sum of square error. The information of an object is determined from the geometric relationships between edges. As an user interface, a versatile image processing program is developed in several modules, and renders a very useful 3D measurement at a limited constraints when adopted in automation of production process. The flexibility of camera position from the algorithm developrf can be used for automated pick and place operations and feeding workpiece u: ;ing assembly robot.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.7
• /
• pp.167-174
• /
• 1998

This paper presents an unoccluded cylindrical object pose measurement using a slit beam laser in which a robot recognizes all of the unoccluded objects from the top of jumbled objects, and picks them up one by one. The elliptical equation parameters of a projected curve edge on a slice are calculated using LSM. The coefficients of standard elliptical equation are compared with these parameters to estimate the object pose. The hamming distances between the estimated coordinates and the calculated ones are extracted as measures to evaluate a local constraint and a smoothing surface curvature. The edges between slices are linked using error function based on the edge types and the hamming distances. The linked edges on slices are compared with the model object's length to recognize the unoccluded object. This proposed method may provide a solution to the automation of part handling in manufacturing environments such as punch press operation or part assembly.