• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.6 no.6
• /
• pp.560-565
• /
• 2005

This paper deals with the development of manually operated die used for the manufacture of octagonal boxes into two sets of automated die. In particular, theoctagonal boxes are used fur the switch boxes intended fur the cable conduit of buildings or f3r wiring connection. Manufacturing these boxes requires forming the materials using the primary press before they undergo 2nd through 6th processing by the press machine including the four sides of the octagonal outlet box and bending. Such complicated process hikes up labor cost, slows down production, and results in defect rate of $10\%$ or higher; hence the overall rise in manufacturing cost. Moreover, workers avoid this type of work due to the roar and vibration coming from the press and the risk of accident. To eliminate such phenomenon, a CAM die made by integrating five sets of die into one set of die and an automatic conveyor system were developed. As a result, unmanned work was realized with only two units of press and two sets of die; thus solving the problem of work being avoided and saving on manufacturing cost.

• Current Industrial and Technological Trends in Aerospace
• /
• v.7 no.2
• /
• pp.59-67
• /
• 2009

Computer Aided Engineering(CAE) technology as well as Design(CAD) and Manufacturing(CAM) have been widely adopted in the aerospace industry in order to develop the structure of airplanes, satellites and launch vehicles. Among them, CAE softwares based on finite element methods such as NASTRAN, ABAQUS and ANSYS have gained many engineers' interest in various industries such as automobiles, civils, aircraft and spacecraft. The softwares usually consist of several modules: Static, Dynamic, Vibration, Impact etc. that make analysis specific to meet the design goals of the structure systems. Recent enhancement in the computer hardwares and numerical algorithms enables us to perform complex analysis like multi-physics, optimum design. Also, they make it possible to deal with a large scale problem easily. This paper reviews structural analysis softwares in aerospace industry and gives a summary on its recent development.

• Journal of Biosystems Engineering
• /
• v.32 no.5
• /
• pp.301-308
• /
• 2007

Sesame has usually been harvested manually in korea. The conventional sesame harvest procedures consists of cutting, binding, drying and pod shattering. The procedures of drying and shattering are repeated $2{\sim}3$ times. By manual works of this conventional shattering, it was found that some extent of pods were has always remained unopened. Therefore, this study was conducted to find a way to save the labor of sesame shattering by use of a drying device; a prototype of shattering machine was developed and tested the performance. The developed prototype consists of several parts: a continuous horizontal inlet using a chain conveyer, a shattering by a shocking agitator, a rotating cone for shattering of remaining closed pods, and a winnow. The shattering ratio measured by this prototype was 90.3%, 6.4% and 3.3% at the first, second and third shattering step, respectively. We found that in contrast to the conventional method which required at least 3 times operations for complete shattering, this shattering prototype with the condition of sufficient dried sesame pod offered more than 90% of shattering ratio in the first operation.

• Journal of Biosystems Engineering
• /
• v.34 no.6
• /
• pp.425-433
• /
• 2009

The developed final shattering machine for labor-saving mechanization of shattering of sesame consisted of input part, shattering part, re-shattering part for unshattered pod and pneumatic sorter. The bundle of sesame was held as upside down and fed into the machine continuously. Then, the fed bundle of sesame was shattered by side shock and agitation. The performance of shattering for the sun dried bundle of sesame of conventional manual work and final shattering machine was compared. Since the shattering ratio measured by the final machine was 97.2% at the first operation, in case of fully dried sesame by drying stand, the harvest of sesame can be completed by only one time shattering operation. The work hour per area of 10 a for the mechanical work and the manual work were 0.3 hour and 13.9 hour, respectively. The total shattering ratio of the final machine with vertical feedings of bundle of sesames was 97.2%.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.5
• /
• pp.45-50
• /
• 2011

Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Conventional method, however, to check compression pressure uniformity is done by mechanical pressure gage and valve timing is checked manually. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and temperature. Also to check valve timing, related FEAD parts should be disassembled and timing mark should be checked. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. Results, it is found that detection of bulky as well as small leaky cylinder is possible by cranking motor current analysis and wrong valve timing can be detected by cylinder pressure analysis and cam and crank sensor signal.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.8C
• /
• pp.711-720
• /
• 2012

In this paper, we introduce the implementation of driver fatigue monitering system and its result. Input video device is selected commercially available web-cam camera. Haar transform is used to face detection and adopted illumination normalization is used for arbitrary illumination conditions. Facial image through illumination normalization is extracted using Haar face features easily. Eye candidate area through illumination normalization can be reduced by anthropometric measurement and eye detection is performed by PCA and Circle Mask mixture model. This methods achieve robust eye detection on arbitrary illumination changing conditions. Drowsiness state is determined by the level on illumination normalize eye images by a simple calculation. Our system alarms and operates seatbelt on vibration through controller area network(CAN) when the driver's doze level is detected. Our algorithm is implemented with low computation complexity and high recognition rate. We achieve 97% of correct detection rate through in-car environment experiments.

• Journal of Computational Design and Engineering
• /
• v.2 no.4
• /
• pp.218-232
• /
• 2015

Piecewise linear (G01-based) tool paths generated by CAM systems lack $G_1$ and $G_2$ continuity. The discontinuity causes vibration and unnecessary hesitation during machining. To ensure efficient high-speed machining, a method to improve the continuity of the tool paths is required, such as B-spline fitting that approximates G01 paths with B-spline curves. Conventional B-spline fitting approaches cannot be directly used for tool path B-spline fitting, because they have shortages such as numerical instability, lack of chord error constraint, and lack of assurance of a usable result. Progressive and Iterative Approximation for Least Squares (LSPIA) is an efficient method for data fitting that solves the numerical instability problem. However, it does not consider chord errors and needs more work to ensure ironclad results for commercial applications. In this paper, we use LSPIA method incorporating Energy term (ELSPIA) to avoid the numerical instability, and lower chord errors by using stretching energy term. We implement several algorithm improvements, including (1) an improved technique for initial control point determination over Dominant Point Method, (2) an algorithm that updates foot point parameters as needed, (3) analysis of the degrees of freedom of control points to insert new control points only when needed, (4) chord error refinement using a similar ELSPIA method with the above enhancements. The proposed approach can generate a shape-preserving B-spline curve. Experiments with data analysis and machining tests are presented for verification of quality and efficiency. Comparisons with other known solutions are included to evaluate the worthiness of the proposed solution.

• Journal of Biosystems Engineering
• /
• v.30 no.4 s.111
• /
• pp.210-219
• /
• 2005

This study was conducted to solve the problem of crawled spinach harvesting that had been mainly done by manpower on the outdoor fields during the winter season. Moreover, there are not enough workers available for farming at most of rural areas in Korea because farming is getting hard and the number of old-aged workers is increasing. In order to find appropriate methods of digging, picking and collecting of spinach, the tests were examined outdoors. A prototype was designed based on the results of the tests and then fabricated for digging, picking-up and then collecting in continuous operation for harvesting spinach planted in the outdoor fields. In the field test with the prototype, the vibration intensity transmitted to the driver by vibrating blade was low while the vibrating blade reduced digging power by $46\%$ compared to that of the fixed blade. The spinach loss was found to be as low as $0.7\%$ in the condition of digging depth of 40 mm, cam rotational velocity of 748 rpm, and blade amplitude of 16.5 m. The working performance of the prototype spinach harvester was found to be 3.8 hour/10a resulting in $96\%$ of labor saving and $85\%$ of operating cost compared to the conventional manual harvesting.