• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1285-1295
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• 2008

A research on a simulator for a side walking path of a 16 degree-of-freedom (d.o.f) biped walking robot(BWR) which is composed of 4 d.o.f upper-part body and 12 d.o.f lower-part of the body is presented. For generation of stable side walking motion, the kinematics, dynamics and the zero moment of point(ZMP) of the BWR were analyzed analytically and included in the simulator. To operate the motion simulator for stable side walking of the BWR, a graphic user interface program was developed which needs inputs for the side distance between legs, base joint angle, walking type, and walking velocity. The simulator was developed to generate joint angle data of legs for side walking, and the data are transmitted to the BWR for stable side walking. In the simulator, a new path function for smooth walking motion was proposed and applied to the simulator and actual motion of a BWR. Also for actual side walking, an algorithm for estimating backlashes of the actuating joint motors was proposed and included in the simulator. To validate the performance of the proposed motion simulator, the simulator was operated and its side walking data of the simulator were generated for a period of side walking.

• 대한기계학회논문집
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• 제17권8호
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• pp.2012-2022
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• 1993

For the machining of the sculptured surfaces on 5-axis CNC milling machine, the milling cutter direction vector was determined in the study (I) with 5-axis post-processing. Thus, it was possible to cut the sculptured surfaces on five-axis CNC milling machine with the end mill cutter. Then, for smooth machined surfaces in five-axis machining of free-from surfaces, this study develops an algorithm for prediction of cusp heights. Also, it generates tool path such that the cusp heights are constrained to a constant value or under a certain value. For prediction of the cusp height between two basis points, a common plane, containing the line crossing two basis points and the summation vector of two normal vectors at two basis points, is defined. The cusp height is the maximum value of scallops on the common plane after end mill cutter passes through the common plane. Sculptured surfaces were machined with CINCINNATI MILACRON 5-axis machining center, model 20V-80, using end mill cutter. Cusp heights were verified by 3-dimensional measuring machine with laser scanner, WEGU Messtechnik GmbH.

• 치과방사선
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• 제18권1호
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• pp.167-176
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• 1988

This study was designed to evaluate the morphology of the temporomandibular joint components and dentofacial characteristics of patients with clicking and painful temporomadibular joint. The materials consisted of 80 conventional pantomographs in normal an symptomatic individuals aged 18-23 and divided into 2 groups by symptom of temporomandibular joint. The results were as follows; 1. In morphologic analysis of condylar head, type Ⅰ (anterior, posterior smooth curve) was most dominant in both group(58.75%, 55.0%) and asymmetrical condylar shape was predominant in symptomatic group (18 cases, 45%). 2. In symptomatic group, the condylar width were slightly lesser and the ratio of condylar height to height of condyle-ramus were larger than those of normal group. 3. Vertical overlap of central incisor of symptomatic group was slightly larger than that of normal group. There was significant differences between each group in mandibular midline deviation. 4. The symptomatic group tended to steep mandibular plane angle and the degree of condylar path and condylar axis of normal group were larger than those of symptomatic group. 5. The condylar width was inversely correlated with inclination of condylar path and inclination of condylar path was correlated with condylar axis in both groups.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.786-791
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• 2003

This paper proposes an adaptive control algorithm for nonholonomic mobile robots with unknown parameters and the proposed control method is used in numerical simulations for applying to a practical twowheeled welding mobile robot(WMR). The proposed adaptive controller to track an arbitrary given welding path is designed by using back-stepping technique and is derived for a nonlinear model under the assumption such that the system parameters are partially known. Moreover, the proposed adaptive control system is stable in the sense of Lyapunov stability. Inertia moments of system are considered to be unknown parameters and their values can be estimated simply by using update laws proposed in an adaptive control scheme of this research. The simulation results are provided to show the effectiveness of the accurate tracking capability of the proposed controller for two-wheeled welding mobile robot with a smooth curved reference welding path.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권2호
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• pp.140-146
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• 2013

In this paper, we describe a vision sensor-based driving algorithm for indoor automatic guided vehicles (AGVs) that facilitates a path tracking task using two mono cameras for navigation. One camera is mounted on vehicle to observe the environment and to detect markers in front of the vehicle. The other camera is attached so the view is perpendicular to the floor, which compensates for the distance between the wheels and markers. The angle and distance from the center of the two wheels to the center of marker are also obtained using these two cameras. We propose five movement patterns for AGVs to guarantee smooth performance during path tracking: starting, moving straight, pre-turning, left/right turning, and stopping. This driving algorithm based on two vision sensors gives greater flexibility to AGVs, including easy layout change, autonomy, and even economy. The algorithm was validated in an experiment using a two-wheeled mobile robot.

• 대한조선학회논문집
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• 제53권2호
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• pp.115-126
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• 2016

In the process of ship building, it is known that the maintenance of working period and saving cost are one of the important part during the logistics of blocks transportation. Precise operational planning inside the shipyard plays a big role for a smooth transportation of blocks. But many problems arise in the process of block transportation such as the inevitable road damage during the transportation of the blocks, unpredictable stockyard utilization of the road associated with a particular lot number, addition of unplanned blocks. Therefore, operational plan needs to be re-established frequently in real time for an efficient block management. In order to find the shortest path between lot numbers, there are several representative methods such as Floyd algorithm that has the characteristics of many-to-many mapping, Dijkstra algorithm that has the characteristic of one-to-many mapping, and the A* algorithm which has the one-to-one mapping, but many authors have published without the mutual comparisons of these algorithms. In this study, some appropriate comparison have been reviewed about the advantages and disadvantages of these algorithms in terms of precision and cost analysis of calculating the paths and planning system to operate the transporters. The flexible operating plan is proposed to handle a situation such as damaged path, changing process during block transportation. In addition, an operational algorithm of a vacant transporter is proposed to cover the shortest path in a minimum time considering the situation of transporter rotation for practical use.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.464-467
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• 2002

국내 건설프로젝트의 경우 건설생산주체간의 정보 흐름이 원할치 못하여 건설 생산성이 저하되는 원인이 되고 있다. 특히 설계단계에서 건축물의 요구성능, 비용조건, 및 주요자재, 시공과정 등에 대한 고려가 미비하여 시공단계에서 설계 오류로 인한 여러 가지 문제점이 발생하고 있다. 또한 설계검토 및 설계 변경시 관련 주체(발주자, 설계자, 시공자 및 건설관리자)간의 커뮤니케이션이 원활하지 못하여 실수가 발생되고 있는 실정이다. 본 연구에서는 건축 설계단계에서 건축물의 성능, 비용 및 시공성을 만족하는 건축 부위 최적화 방법 및 이와 연계하여 설계/시공간의 효율적인 정보 처리 방안을 제시하고자 하였다. 또한 본 연구에서의 건설정보는 건물 구성요소의 접합관계, 기둥의 위치, 부위별 시공성 정보 및 현장 제한조건 정보 등 설계 단계에서 고려해야할 설계${\cdot}$시공 정보로 제한하였다. 본 연구에서 제시하는 방법은 건축 시스템의 최적화를 통해 건축설계단계에서 건축물의 성능 및 건물 총생애비용(LCC)과 시공단계의 시공성을 만족하는 건축부위 대안 생성과 이러한 과정에서 발생되는 관련주체간의 커뮤니케이션을 체계화하는 것이다.

• 전자공학회논문지S
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• 제35S권10호
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• pp.64-76
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• 1998

본 논문에서 4-구륜 2-자유도 이동 로보트의 체계적인 동적 모델링과 경로설계 및 추적 알고리즘을 제안한다. 실시간에서 이동 로보트의 위치 측정을 위해 관성측정장치중의 3가지 요소를 이용한다. 이러한 장치들은 지구의 회전속도 및 중력가속도 등의 여러 요인으로 인해 초기 오차를 가진다. 그래서 초기오차 모델을 유도하고, 실제 데이터와 유도된 모델의 추정 데이터의 확률적 특성을 분석 ${\cdot}$ 비교하여 적합도를 판정하여 사용한다. 관성측정장치의 동작특성은 오차모델과 칼만 필터와 연계된 경우와 배제된 일반적인 경우와 비교한다. 모의실험 결과들은 제안된 경로설계 및 추적 알고리즘이 기존의 방식과 비교하여 보다 유용함을 입증한다.

• 한국건설관리학회논문집
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• 제4권2호
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• pp.91-98
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• 2003

국내 건축설계 프로젝트에서는 협력업체간의 커뮤니케이션이 원활치 못하여 건축 부위 설계 시 성능 및 비용을 만족하는 적절한 설계대안 생성이 어려울 뿐 아니라, 설계단계에서부터 시공단견1에 이르기까지 다양한 원인으로 발생되는 설계변경에 적절히 대응하지 못하고 있다. 따라서 분야별 설계도서의 불일치로 인한 시공 품질 저하 등의 문제가 발생되고 있다. 이에 따라 본 연구에서는 건축설계단계에서 합리적인 건축설계대안 생성을 위한 협력설계 의사결정 지원시스템 구축방법의 개념을 제시하였다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.315-318
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• 2003

국내 건축설계 프로젝트에서는 협력업체간의 커뮤니케이션이 원활치 못하여 건축 부위 설계시 성능 및 비용을 만족하는 적절한 설계대안 생성이 어려울 뿐 아니라, 설계단계에서부터 시공단계에 이르기까지 다양한 원인으로 발생되는 설계변경에 적절히 대응하지 못하고 있다. 따라서 분야별 설계도서의 불일치로 인한 시공 품질 저하 등의 문제가 발생되고 있다. 이에 따라 본 연구에서는 건축 중간설계단계에서 합리적인 건축설계대안 생성을 위한 협력 의사결정 지원 프로세스 구축방법을 제시하였다.