• Title/Summary/Keyword: Mechanical system

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Method of Bicycle Configuration Design Based on Part-Shape Information Model (부품 형상 정보 모델 기반의 자전거 편집설계 방법)

  • Lee, Jaesun;Kim, Byung Chul;Lee, Hanmin;Park, Seong Whan;Myung, Byung Soo;Mun, Duhwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.3
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    • pp.74-84
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    • 2015
  • The core activities of a bicycle manufacturer are design, engineering analysis, and manufacturing. Therefore, it is important to develop a configuration design system for bicycles in order to automate the design process and facilitate the use of design data in engineering analysis and manufacturing. In this paper, we present a method to develop a bicycle configuration design system based on the part-shape information model. The proposed method enables the construction of a CAD library using modeling functions with equations and parameters that are common to most 3D mechanical CAD systems. Furthermore, the part-shape information model ensures the independence between the configuration design system and the library, making it possible to extend the CAD library flexibly without changing the system architecture.

Grain size measurement based on marked watershed algorithm (유역분할 알고리즘을 이용한 결정립 크기 측정)

  • Kim, Beomsoo;Yoon, Sangdoo;Kwon, Jaesung;Choi, Sungwoong;Noh, Jungpil;Yang, Jeonghyeon
    • Journal of the Korean institute of surface engineering
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    • v.55 no.6
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    • pp.403-407
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    • 2022
  • Grain size of material is important factor in evaluating mechanical properties. Methods for grain size determination are described in ASTM grain size standards. However, conventional method require pretreatment of the surface to clarify grain boundaries. In this study, the grain size from the surface image obtained from scanning electron microscope was measured using the watershed algorithm, which is a region-based method among image segmentation techniques. The shapes of the crystals are similar to each other, but the size and growth height are different. In addition, crystal grains are adjacent to each other, so it is very similar to the shape image of the topography. Therefore, grain boundaries can be efficiently detected using the Watershed algorithm.

Implementation of an Autonomous Driving System for the Segye AI Robot Car Race Competition (세계 AI 로봇 카레이스 대회를 위한 자율 주행 시스템 구현)

  • Choi, Jung Hyun;Lim, Ye Eun;Park, Jong Hoon;Jeong, Hyeon Soo;Byun, Seung Jae;Sagong, Ui Hun;Park, Jeong Hyun;Kim, Chang Hyun;Lee, Jae Chan;Kim, Do Hyeong;Hwang, Myun Joong
    • The Journal of Korea Robotics Society
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    • v.17 no.2
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    • pp.198-208
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    • 2022
  • In this paper, an autonomous driving system is implemented for the Segye AI Robot Race Competition that multiple vehicles drive simultaneously. By utilizing the ERP42-racing platform, RTK-GPS, and LiDAR sensors provided in the competition, we propose an autonomous driving system that can drive safely and quickly in a road environment with multiple vehicles. This system consists of a recognition, judgement, and control parts. In the recognition stage, vehicle localization and obstacle detection through waypoint-based LiDAR ROI were performed. In the judgement stage, target velocity setting and obstacle avoidance judgement are determined in consideration of the straight/curved section and the distance between the vehicle and the neighboring vehicle. In the control stage, adaptive cruise longitudinal velocity control based on safe distance and lateral velocity control based on pure-pursuit are performed. To overcome the limited experimental environment, simulation and partial actual experiments were conducted together to develop and verify the proposed algorithms. After that, we participated in the Segye AI Robot Race Competition and performed autonomous driving racing with verified algorithms.

A System for Rapid Design and Manufacturing of Custom-Tailored Shoes

  • Park, Sang-Kun;Lee, Kun-Woo;Kim, Jong-Won;Park, Jong-Woo
    • Journal of Mechanical Science and Technology
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    • v.14 no.6
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    • pp.675-689
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    • 2000
  • Rapid design and production techniques are indispensable for the custom-made production systems. For manufacturing custom-made shoes, the shoelast should be designed rapidly from the individual foot model. In this paper, we develop an integrated system for rapid design and manufacturing of custom-tailored shoes. The foot shape measurement sub-system allows scanning a standard shoelast and an individual foot and then extracts the three-dimensional crosssectional data of the shoelast and the human foot shape from the captured image data. The shoelast design sub-system uses the scanned data to design new customized shoelast curves or surfaces with the heeling and mixing algorithms built in this system. The pattern design subsystem provides a method, which transforms a shoe-upper surface designed by a stylist into a flat-pattern that can be manufactured. We also export the surface model to an NC machine to manufacture the physical shoelast model.

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Nonlinear control of underactuated mechanical systems via feedback linearization and energy based Lyapunov function

  • Hong, Keum-Shik;Sohn, Sung-Chul;Yang, Kyung-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.77-80
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    • 1996
  • In this paper a nonlinear control strategy via feedback linearization and energy based Lyapunov function for underactuated mechanical systems is investigated. Underactuated mechanical system is a system of which the number of actuators is less than the number of degrees of freedom. Developed algorithm is applied to a crane system of grab operation. Positioning of the trolley as well as swing-up of the pendulum to the up-right position including maintaining the sway angle at some desired degree are demonstrated. Simulations are provided.

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A Multi-target Tracking Algorithm for Application to Adaptive Cruise Control

  • Moon Il-ki;Yi Kyongsu;Cavency Derek;Hedrick J. Karl
    • Journal of Mechanical Science and Technology
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    • v.19 no.9
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    • pp.1742-1752
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    • 2005
  • This paper presents a Multiple Target Tracking (MTT) Adaptive Cruise Control (ACC) system which consists of three parts; a multi-model-based multi-target state estimator, a primary vehicular target determination algorithm, and a single-target adaptive cruise control algorithm. Three motion models, which are validated using simulated and experimental data, are adopted to distinguish large lateral motions from longitudinally excited motions. The improvement in the state estimation performance when using three models is verified in target tracking simulations. However, the performance and safety benefits of a multi-model-based MTT-ACC system is investigated via simulations using real driving radar sensor data. The MTT-ACC system is tested under lane changing situations to examine how much the system performance is improved when multiple models are incorporated. Simulation results show system response that is more realistic and reflective of actual human driving behavior.