• Title, Summary, Keyword: Trajectory

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Trajectory Recovery Using Goal-directed Tracking (목표-지향 추적 기법을 이용한 궤적 복원 방법)

  • Oh, Seon Ho;Jung, Soon Ki
    • Journal of Korea Multimedia Society
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    • v.18 no.5
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    • pp.575-582
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    • 2015
  • Obtaining the complete trajectory of the object is a very important task in computer vision applications, such as video surveillance. Previous studies to recover the trajectory between two disconnected trajectory segments, however, do not takes into account the object's motion characteristics and uncertainty of trajectory segments. In this paper, we present a novel approach to recover the trajectory between two disjoint but associated trajectory segments, called goal-directed tracking. To incorporate the object's motion characteristics and uncertainty, the goal-directed state equation is first introduced. Then the goal-directed tracking framework is constructed by integrating the equation to the object tracking and trajectory linking process pipeline. Evaluation on challenging dataset demonstrates that proposed method can accurately recover the missing trajectory between two disconnected trajectory segments as well as appropriately constrain a motion of the object to the its goal(or the target state) with uncertainty.

Smooth Walking Robot Using Genetic Algorithm (유전알고리즘을 이용한 유연한 보행로봇)

  • 한경수;김상범;김진걸
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.450-453
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    • 2002
  • This paper is concerned with smooth walking robot using genetic algorithm. The new walking algorithm is proposed and we simulated and experimented the algorithm. We suggested the leg trajectory algorithm and balancing trajectory algorithm by applying genetic algorithm. First the leg trajectory algorithm generated the smooth trajectory. Also the balancing trajectory generated the optimal trajectory. We compared results with the previous walking algorithm. It showed that the new proposed algorithm generated the better walking trajectory.

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The Driving Trajectory Measurement and Analysis Techniques using Conventional GPS Sensor for the Military Operation Environments (군운용 환경에 적합한 GPS 센서기반 주행궤적 측정 및 분석 기술)

  • Jung, Ilgyu;Ryu, Chiyoung;Kim, Sangyoung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.6
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    • pp.774-780
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    • 2017
  • The techniques for driving trajectory calculation and driving trajectory distribution calculation are proposed to analyze the durability of ground vehicles effectively. To achieve this aim, the driving trajectory of a vehicle and the driving trajectory distribution of that are needed, in addition to road profile. The road profiles can be measured by a profilometer but a driving trajectory of a vehicle cannot be acquired effectively due to a large position error from a conventional GPS sensor. Therefore two techniques are proposed to reduce the position error of a vehicle and achieve the distribution of driving trajectory of that. The driving trajectory calculation technique produces relative positions by using the velocity, time and heading of a vehicle. The driving trajectory distribution calculation technique produces distributions of the driving trajectory by using axis transformation, estimating reference line, dividing sectors and plotting a histogram of the sectors. As a results of this study, we can achieve the considerably accurate driving trajectory and driving trajectory distribution of a vehicle.

Analysis of the elliptical shooting trajectory for tuna purse seine (참치선망어선의 타원형 투망궤적 분석)

  • LEE, Da-Yun;LEE, Chun-Woo;CHOI, Kyusuk;JANG, Yongsuk
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.56 no.1
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    • pp.1-10
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    • 2020
  • In the previous study, a shooting trajectory assuming that the purse seine shooting trajectory is a circle was proposed based on the speed and direction of the movement of the fish school. However, in practice, a trajectory that is closer to an elliptical shape than a circular one is often formed. In this study, the existing circular trajectory and the elliptical trajectory methods were compared under the same conditions to confirm the effectiveness of elliptical shooting trajectory. In addition, changes in the eccentricity of ellipses were derived to assess which type of ellipse was appropriate as a shooting trajectory. When a high-speed fish school moves in a straight line, an elliptical shooting trajectory with the eccentricity of 0.7 to 0.9 will be reasonable, and for middle-low speed fish school, an elliptical shooting trajectory with the eccentricity of 0.4 to 0.6 will be more useful than a circle shooting trajectory.

FLIGHT TRAJECTORY CONTOLLER FOR NONLINEAR MANEUVER(GENERATION OF A DESIRED TRAJECTORY BY SPLINE THEORY)

  • Baba, Yoriaki;Takano, Hiroyuki;Sano, Masaki
    • 제어로봇시스템학회:학술대회논문집
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    • pp.376-379
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    • 1995
  • To force an aircraft to track the specified path, the generation of the smooth desired trajectory is essential. In this paper, the cubic spline function is used to generate the trajectory which passes through the specified intercept points. The simulation results show that the desired trajectory generated by the spline interpolation is very smooth and the aircraft tracks it with small position errors.

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Trajectory Planning for Industrial Robot Manipulators Considering Assigned Velocity and Allowance Under Joint Acceleration Limit

  • Munasinghe, S.Rohan;Nakamura, Masatoshi;Goto, Satoru;Kyura, Nobuhiro
    • International Journal of Control, Automation, and Systems
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    • v.1 no.1
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    • pp.68-75
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    • 2003
  • This paper presents an effective trajectory planning algorithm for industrial robot manipulators. Given the end-effector trajectory in Cartesian space, together with the relevant constraints and task specifications, the proposed method is capable of planning the optimum end-effector trajectory. The proposed trajectory planning algorithm considers the joint acceleration limit, end-effector velocity limits, and trajectory allowance. A feedforward compensator is also incorporated in the proposed algorithm to counteract the delay in joint dynamics. The algorithm is carefully designed so that it can be directly adopted with the existing industrial manipulators. The proposed algorithm can be easily programmed for various tasks given the specifications and constraints. A three-dimensional test trajectory was planned with the proposed algorithm and tested with the Performer MK3s industrial manipulator. The results verified effective manipulator performance within the constraints.

Comparative Analysis of Cartesian Trajectory and MultiVane Trajectory Using ACR Phantom in MRI : Using Image Intensity Uniformity Test and Low-contrast Object Detectability Test (ACR 팬텀을 이용한 Cartesian Trajectory와 MultiVane Trajectory의 비교분석 : 영상강도 균질성과 저대조도 검체 검출률 test를 사용하여)

  • Nam, Soon-Kwon;Choi, Joon-Ho
    • Journal of radiological science and technology
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    • v.42 no.1
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    • pp.39-46
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    • 2019
  • This study conducted a comparative analysis of differences between cartesian trajectory in a linear rectangular coordinate system and MultiVane trajectory in a nonlinear rectangular coordinate system axial T1 and axial T2 images using an American College of Radiology(ACR) phantom. The phantom was placed at the center of the head coil and the top-to-bottom and left-to-right levels were adjusted by using a level. The experiment was performed according to the Phantom Test Guidance provided by the ACR, and sagittal localizer images were obtained. As shown in Figure 2, slices # 1 and # 11 were scanned after placing them at the center of a $45^{\circ}$ wedge shape, and a total of 11 slices were obtained. According to the evaluation results, the image intensity uniformity(IIU) was 93.34% for the cartesian trajectory, and 93.19% for the MultiVane trajectory, both of which fall under the normal range in the axial T1 image. The IIU for the cartesian trajectory was 0.15% higher than that for the MultiVane trajectory. In axial T2, the IIU was 96.44% for the cartesian trajectory, and 95.97% for the MultiVane trajectory, which fall under the normal range. The IIU for the cartesian trajectory was by 0.47% higher than that for the MultiVane trajectory. As a result, the cartesian technique was superior to the MultiVane technique in terms of the high-contrast spatial resolution, image intensity uniformity, and low-contrast object detectability.

Design and Implementation of a Trajectory-based Index Structure for Moving Objects on a Spatial Network (공간 네트워크상의 이동객체를 위한 궤적기반 색인구조의 설계 및 구현)

  • Um, Jung-Ho;Chang, Jae-Woo
    • Journal of KIISE:Databases
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    • v.35 no.2
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    • pp.169-181
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    • 2008
  • Because moving objects usually move on spatial networks, efficient trajectory index structures are required to achieve good retrieval performance on their trajectories. However, there has been little research on trajectory index structures for spatial networks such as FNR-tree and MON-tree. But, because FNR-tree and MON-tree are stored by the unit of the moving object's segment, they can't support the whole moving objects' trajectory. In this paper, we propose an efficient trajectory index structure, named Trajectory of Moving objects on Network Tree(TMN Tree), for moving objects. For this, we divide moving object data into spatial and temporal attribute, and preserve moving objects' trajectory. Then, we design index structure which supports not only range query but trajectory query. In addition, we divide user queries into spatio-temporal area based trajectory query, similar-trajectory query, and k-nearest neighbor query. We propose query processing algorithms to support them. Finally, we show that our trajectory index structure outperforms existing tree structures like FNR-Tree and MON-Tree.

Analytic Solution for Stable Bipedal Walking Trajectory Generation Using Fourier Series (푸리에 급수를 이용한 이족보행로봇의 보행 궤적 해석해 생성)

  • Park, Ill-Woo;Back, Ju-Hoon
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.12
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    • pp.1216-1222
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    • 2009
  • This article describes a simple method for generating the walking trajectory for the biped humanoid robot. The method used a simple inverted model instead of complex multi-mass model and a reasonable explanation for the model simplification is included. The problem of gait trajectory generation is to find the solution from the desired ZMP trajectory to CoG trajectory. This article presents the analytic solution for the bipedal gait generation on the bases of ZMP trajectory. The presented ZMP trajectory has Fourier series form, which has finite or infinite summation of sine and cosine functions, and ZMP trajectory can be designed by calculating the coefficients. From the designed ZMP trajectory, this article focuses on how to find the CoG trajectory with analytical way from the simplified inverted pendulum model. Time segmentation based approach is adopted for generating the trajectories. The coefficients of the function should be designed to be continuous between the segments, and the solution is found by calculating the coefficients with this connectivity conditions. This article also has the proof and the condition of solution existence.

Reference Trajectory Analysis of Atmosphere Re-entry for Space Vehicle (우주비행체의 대기권 재진입 기준궤적 해석)

  • 이대우;조겸래
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.6
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    • pp.111-118
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    • 2000
  • The design of reference trajectory with respect to drag acceleration is necessary to decelerate from hypersonic speed safely after atmosphere re-entry of space vehicle. The re-entry guidance design involves trajectory optimization, generation of a reference drag acceleration profile with the satisfaction of 6 trajectory constraints during the re-entry flight. This reference drag acceleration profile can be considered as the reference trajectory. The cost function is composed of the accumulated total heating on vehicle due to the reduction of weight. And a regularization is needed to prevent optimal drag profile from varying too fast and achieve realized trajectory. This paper shows the relations between velocity, drag acceleration and altitude in drag acceleration profile, and how to determine the reference trajectory.

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