• Title, Summary, Keyword: Kinematic Constraints

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A study on the dynamic modeling of driving system of a heavy industrial vehicle (중장비 구동체계의 제어용 동적 모델에 관한 연구)

  • 홍성욱;강민식;이종원;김광준
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.2
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    • pp.222-233
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    • 1987
  • A dynamic modeling procedure for developing a control model of the driving system of a heavy industrial vehicle is presented. The dynamic model is derived by applying generalized Lagrangian equations to each component of the system and imposing kinematic relations between components as constraints. In order to obtain the control model, a few assumptions are made for the simplification of the nonlinear and complicated model, which is justified by the comparison of the simulation results of the original full nonlinear model and the simplified control model.

Modal Analysis of Suspension System with Kinematic Constraints and Elastic Elements (기구학적 구속조건과 탄성요소를 가진 현가계의 모드해석)

  • 이장무;강주석;윤중락;배상우;탁태오
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.1
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    • pp.110-123
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    • 2000
  • In this Study, the dynamic equation for vibration analysis of mechanical systems with kinematic constraints is derived. This equations are derived in terms of small displacements of Cartesian coordinates, and are applied to compute the dynamic response and the natural modes of the suspension system of a vehicle. The results are validated through the comparison with the results from conventional nonlinear dynamic analysis and modal test.

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Path Planning for Parking using Multi-dimensional Path Grid Map (다차원 경로격자지도를 이용한 주차 경로계획 알고리즘)

  • Choi, Jong-An;Song, Jae-Bok
    • The Journal of Korea Robotics Society
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    • v.12 no.2
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    • pp.152-160
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    • 2017
  • Recent studies on automatic parking have actively adopted the technology developed for mobile robots. Among them, the path planning scheme plans a route for a vehicle to reach a target parking position while satisfying the kinematic constraints of the vehicle. However, previous methods require a large amount of computation and/or cannot be easily applied to different environmental conditions. Therefore, there is a need for a path planning scheme that is fast, efficient, and versatile. In this study, we use a multi-dimensional path grid map to solve the above problem. This multi-dimensional path grid map contains a route which has taken a vehicle's kinematic constraints into account; it can be used with the $A^*$ algorithm to plan an efficient path. The proposed method was verified using Prescan which is a simulation program based on MATLAB. It is shown that the proposed scheme can successfully be applied to both parallel and vertical parking in an efficient manner.

Collision prediction and detection in a dynamic environment (동적 환경하에서의 충돌 예측 및 감지)

  • 한인환;양우석
    • 제어로봇시스템학회:학술대회논문집
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    • pp.309-314
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    • 1992
  • Many dynamic mechanical systems, such as parts-feeders, walking machines, and percussive power tools, are described by equations of motion which are discontinuous. The discontinuities result from kinematic constraint changes which are difficult to foresee, especially in presence of impact. A simulation algorithm for these types of systems must be able to algorithmically predict and detect the kinematic constraint changes without any prior knowledge of the system's motion. This paper presents a rule-based approach to the prediction and detection of kinematic constraint changes between bodies with arc and line boundaries. The developed algorithm's ability to accurately and automatically detect the unpredicted changes of kinematic constraints is demonstrated with a numerical example.

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Robust Adaptive Control of a Nonholonomic Mobile Robot

  • Kim, M. S.;Lee, J. J.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.5-8
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    • 1999
  • The main stream of researches on the mobile robot is planning motions of the mobile robot under nonholonomic constraints while only considering kinematic model of a mobile robot. These researches, however, assume that there is some kind of dynamic controller which can produce perfectly the same velocity that is necessary for the kinematic controller. Moreover, there are little results about the problem of integrating the nonholonomic kinematic controller and the dynamic controller for a mobile robot. Also the literature on the robustness of the controller in the presence of uncertainties or external disturbances in the dynamical model of a mobile robot is very few. Thus, in this paper, the robust adaptive controller which can achieve velocity tracking while considering not only kinematic model but also dynamic model of the mobile robot is proposed. The stability of the dynamic system will be shown through the Lyapunov method.

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Analysis and Design of Constant-Force Mechanisms Using a Linear Spring (선형 스프링을 이용한 상력 메커니즘의 분석 및 설계)

  • Kim, Whee-Kuk;Kim, Hae-Soo;Kim, Min-Gun;Yi, Byung-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.2
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    • pp.215-222
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    • 2003
  • In this paper, kinematic analysis and design of constant force mechanisms which employ a linear spring are studied. Firstly, sufficient conditions for the mechanisms to be the constant force mechanisms are derived in terms of displacement variables through the kinematic analysis. Secondly, a few conceptual mechanisms satisfying these constraints are proposed.

Dynamic Analysis of Multi-Robot System Forcing Closed Kinematic Chain (복수로봇 시스템의 동력학적 연구-대상물과 닫힌 체인을 형성할때의 문제-)

  • 유범상
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.4
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    • pp.1023-1032
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    • 1995
  • The multiple cooperating robot system plays an important role in the research of modern manufacturing system as the emphasis of production automation is more on the side of flexibility than before. While the kinematic and dynamic analysis of a single robot is performed as an open-loop chain, the dynamic formulation of robot in a multiple cooperating robot system differs from that of a single robot when the multiple cooperating robots form a closed kinematic chain holding an object simultaneously. The object may be any type from a rigid body to a multi-joint linkage. The mobility of the system depends on the kinematic configuration of the closed kinematic chain formed by robots and object, which also decides the number of independent input parameters. Since the mobility is not the same as the number of robot joints, proper constraint condition is sought. The constraints may be such that : the number of active robot joints is kept the same as mobility, all robot joints are active and have interrelations between each joint forces/torques, two robots have master-slave relation, or so on. The dynamic formulation of system is obtained. The formulation is based on recursive dual-number screw-calculus Newton-Eulerian approach which has been used for single robot analysis. This new scheme is recursive and compact symbolically and may facilitate the consideration of the object in real time.

A Near Minimum-Time Trajectory Planning for Two Robots Using Dynamic Programming Technique (다이나믹 프로그래밍에 의한 두 대의 로보트를 위한 최소시간 경로계획)

  • 이지홍;오영석
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.29B no.11
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    • pp.36-45
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    • 1992
  • A numerical trajectory planning method for path-constrained trajectory planning is proposed which ensures collision-free and time-optimal motions for two robotic manipulators with limited actuator torques and velocities. For each robot, physical constraints of the robots such as limited torques or limited rotational velocities of the actuators are converted to the constraints on velocity and acceleration along the path, which is described by a scalar variable denoting the traveled distance from starting point. Collision region is determined on the coordination space according to the kinematic structures and the geometry of the paths of the robots. An Extended Coordination Space is then constructed` an element of the space determines the postures and the velocities of the robots, and all the constraints described before are transformed to some constraints on the behaviour of the coordination-velocity curves in the space. A dynamic programming technique is them provided with on the discretized Extended Coordination Space to derive a collision-free and time-optimal trajectory pair. Numerical example is included.

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Using multiple point constraints in finite element analysis of two dimensional contact problems

  • Liu, C.H.;Cheng, I.;Tsai, An-Chi;Wang, Lo-Jung;Hsu, J.Y.
    • Structural Engineering and Mechanics
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    • v.36 no.1
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    • pp.95-110
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    • 2010
  • Two-dimensional elastic contact problems, including normal, tangential, and rolling contacts, are treated with the finite element method in this study. Stress boundary conditions and kinematic conditions are transformed into multiple point constraints for nodal displacements in the finite element method. Upon imposing these constraints into the finite element system equations, the calculated nodal stresses and nodal displacements satisfy stress and displacement contact conditions exactly. Frictional and frictionless contacts between elastically identical as well as elastically dissimilar materials are treated in this study. The contact lengths, sizes of slip and stick regions, the normal and the shear stresses can be found.

A Study on Kinematic Characteristics of Planetary Gear Train (유성기어열의 기구학적 특성분석에 관한 연구)

  • 박세환;신중호;윤호업;김대원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.643-646
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    • 1997
  • Gear trains are used in many machinery for variable speed ratios. Typical shapes of gear trains are tivo categories : simple gear trains and planetary gear trains. This paper presents the kinematic ctraracteristics for planetary gear trains. The characteristics are the constraints of geometric relationships, number of gears, speed of each gear. and speed ratio of the train. The objective goal of this paper provides the CAI) software, which is the academic tool for understanding the kinematics of the planetary gear trains.

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