• Title/Summary/Keyword: Kinematic control

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A Solution to the Inverse Kinematic by Using Neural Network (신경 회로망을 사용한 역운동학 해)

  • 안덕환;양태규;이상효
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.15 no.4
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    • pp.295-300
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    • 1990
  • Inverse kinematic problem is a crucial point for robot manipulator control. In this paper, to implement the Jacobian control technique we used the Hopfield, Tank's neural network. The states of neurons represent joint velocities, and the connection weights are determined from the current value of the Jacobian matirx. The network energy function is constructed so that its minimum corresponds to the minimum least square error. At each sampling time, connection weights and neuron states are updated according to current joint positon. Inverse kinematic solution to the planar redundant manipulator is solved by computer simulation.

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Motion Planning Algorithms for Kinematically Redundant Manipulator Not Fixed to the Ground (지면에 고정되어 있지 않은 여유자유도 매니플래이터의 운동계획 알고리즘)

  • 유동수;소병록;김희국
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.10
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    • pp.869-877
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    • 2004
  • This paper deals with motion planning algorithm for kinematically redundant manipulators that are not fixed to the ground. Differently from usual redundant manipulators fixed to the ground, the stability issue should be taken into account to prevent the robot from falling down. The typical ZMP equation, which is employed in human walking, will be employed to evaluate the stability. This work proposes a feed forward ZMP planning algorithm. The algorithm embeds the 'ZMP equations' indirectly into the kinematics of the kinematic model of a manipulator via a ZMP stability index The kinematic self motion of the redundant manipulator drives the system in such a way to keep or plan the ZHP at the desired position of the footprint. A sequential redundancy resolution algorithm exploiting the remaining kinematic redundancy is also proposed to enhance the performances of joint limit index and manipulability. In addition, the case exerted by external forces is taken into account. Through simulation for a 5 DOF redundant robot model, feasibility of the proposed algorithms is verified. Lastly, usual applications of the proposed kinematic model are discussed.

Leg Length Discrepancy to Influence on Kinematic Changes of the Pelvis and the Hip during Gait

  • Yong, MinSik;Park, SoHyun
    • The Journal of Korean Physical Therapy
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    • v.31 no.6
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    • pp.368-371
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    • 2019
  • Purpose: The purpose of this study was to investigate the effects of leg length discrepancy on kinematic changes of the pelvis and hip during gait. Methods: A total of ten healthy women with no history of neurological, musculoskeletal surgery or injuries, or pain in the lower limbs were recruited. They were assigned to two groups; the experimental group (LLD) consisting of five subjects leg length discrepancy of 10mm to 18mm and the control group (CON) consisting of five subjects leg length discrepancy of<10 mm. All participants were instructed to perform three walking trials for further analysis by using the Cortex 3.0 software program. Independent T-test and Mann-Whitney test were used to examine the effects of mild LLD on kinematic changes of the pelvis and hip during gait. Results: Angles of hip flexion, hip abduction, pelvic obliquity, and pelvic tilt in the experimental group were not significantly different compared to those of the control group. Conclusion: Mild leg length discrepancy induces kinematic changes in the lower limbs, including decreased hip flexion, increased hip abduction, and increased pelvic obliquity in the shorter limb, and increased hip adduction and increased pelvic obliquity in the longer limb. However, those changes were not significant.

Quality Test and Control of Kinematic DGPS Survey Results

  • Lim, Sam-Sung
    • Journal of Korean Society for Geospatial Information Science
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    • v.10 no.5 s.23
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    • pp.75-80
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    • 2002
  • Depending upon geographical features and surrounding errors in the survey field, inaccurate positioning is inevitable in a kinematic DGPs survey. Therefore, a data inaccuracy detection algorithm and an interpolation algorithm are essential to meet the requirement of a digital map. In this study, GPS characteristics are taken into account to develop the data inaccuracy detection algorithm. Then, the data interpolation algothim is obtained, based on the feature type of the survey. A digital map for 20km of a rural highway is produced by the kinematic DGPS survey and the features of interests are lines associated with the road. Since the vertical variation of GPS data is relatively higher, the trimmed mean of vertical variation is used as criteria of the inaccuracy detection. Four cases of 0.5%, 1%, 2.5% and 5% trimmings have been experimented. Criteria of four cases are 69cm, 65cm, 61cm and 42cm, respectively. For the feature of a curved line, cublic spine interpolation is used to correct the inaccurate data. When the feature is more or less a straight line, the interpolation has been done by a linear polynomial. Difference between the actual distance and the interpolated distance are few centimeters in RMS.

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Investigation of Kinematic Relation Between Actuator and Control Surface Deflection Using Aileron Linkage Analysis (에일러론 링키지 해석을 통한 작동기 변위와 조종면 변위의 상관관계 규명)

  • Lee, Sugchon;Lee, Sang-Jong
    • Journal of Aerospace System Engineering
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    • v.6 no.3
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    • pp.24-28
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    • 2012
  • An actuator should be added to a existing control linkage to make manned aircraft to unmanned. But it is quiet difficult to synchronize actuator with control surface because non-linear error necessarily occurs when four-bar linkage acts in three dimensional motion. In addition, in point of controller design view, while a real-time model needs the control surface deflection as its input, controller needs the actuator command as its output. Hence, the relation between both should be investigated. In this paper, the mathematical relation between actuator and control surface deflection investigated by kinematic analysis of a plant aircraft. The performance margin of the selected actuator also was verified.

Formation Control of Mobile Robot for Moving Object Tracking (이동물체 추적을 위한 이동로봇의 대형제어)

  • Oh, Young-Suk;Lee, Chung-Ho;Park, Jong-Hun;Kim, Jin-Hwan;Huh, Uk-Youl
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.856-861
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    • 2011
  • The mobile robot controller is designed to track the target and to maintain the formation at the same time. Formation control is included in mobile robot controller by extending the trajectory tracking algorithm. The dynamic model of mobile robot is used with kinematic model considering the practical physical parameters of mobile robot. The dynamic model of mobile robot transforms velocity control input of kinematic model into torque control input which is the practical control input of mobile robot. Formation controller of mobile robot is designed to satisfy Lyapunov stability by backstepping method. The designed formation controller is applied to the mobile robot for various target movements and simulated to confirm the Lyapunov stability.

The Development of an Inverse Kinematic Solution for Periodic Motion of a Redundant Manipulator (여유자유도 로봇의 주기적 운동제어를 위한 역기구학 해의 개발)

  • 정용섭;최용제
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.142-149
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    • 1995
  • This paper presents a new kinematic control strategy for serial redundant manipulators which gives repeatability in the joint space when the end-effector undergoes some general cyclic motions. Theoretical development has been accomplished by deriving a new inverse kinematic equation that is based on springs being conceptually located in the joints of the manipulator. Although some inverse kinematic equations for serial redundant manipulators have been derived by many researchers, the new strategy is the first to include the free angles of torsional springs and the free lengths of the translational springs. This is important because it ensures repeatability in the joint space of a serial redundant manipulator whose end-effector undergoes a cyclic type motion. Numerical verification for repeatability is done in terms of Lie Bracket Condition. Choices for the free angle and torsional stiffness of a joint (or the free length and translational stiffness) are made based upon the mechanical limits of the joints.

Kinematic analysis of a 6-degree-of-freedom micro-positioning parallel manipulator (6자유도를 갖는 정밀 위치제어용 병렬 매니퓰레이터의 기구학 해석)

  • 박주연;심재홍;권동수
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.213-216
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    • 1996
  • This paper studies a class of in-parallel manipulators with special geometry where the forward displacement analysis problem can be solved easier than the fully parallel manipulators. Three horizontal links of this mechanism provide 3DOFs(Degrees of Freedom), which are one degree of orientational freedom and two degrees of translatory freedom. Three vertical links of this mechanism provide 3DOFs, which are two degrees of orientational freedom and one degree of translatory freedom. The main advantages of this manipulator, compared with the Stewart platform type, are the capability to produce pure rotation and to predict the motion of the moving platform easily. Since this manipulator has simple kinematic characteristics compared with the Stewart platform, controlling in real-time is possible due to less computational burden. The purpose of this investigation is to develope an analytical method and systematic method to analyze the basic kinematics of the manipulator. The basic kinematic equations of the manipulator are derived and simulation is carried out to show the performance of the mechanism.

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Analysis of Kinematic Mapping Between an Exoskeleton Master Robot and a Human Like Slave Robot With Two Arms

  • Song, Deok-Hee;Lee, Woon-Kyu;Jung, Seul
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2154-2159
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    • 2005
  • This paper presents the kinematic analysis of two robots, an exoskeleton type master robot and a human like slave robot with two arms. Two robots are designed and built to be equivalent as motion following robots. The operator wears the exoskeleton robot to generate motions, then the slave robot is required to follow after the motion of the master robot. However, different kinematic configuration yields position mismatches of the end-effectors. To synchronize motions of two robots, kinematic analysis of mapping is analyzed. The forward and inverse kinematics have been simulated and the corresponding experiments are also conducted to confirm the proposed mapping analysis.

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A Fast Forward Kinematic Analysis of Stewart Platform (스튜어트 플랫폼의 빠른 순기구학 해석)

  • Ha, Hyeon-Pyo;Han, Myeong-Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.3
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    • pp.339-352
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    • 2001
  • The inverse kinematics problem of Stewart platform is straightforward, but no closed form solution of the forward kinematic problem has been presented. Since we need the real-time forward kinematic solution in MIMO control and the motion monitoring of the platform, it is important to acquire the 6 DOF displacements of the platform from measured lengths of six cylinders in small sampling period. Newton-Raphson method a simple algorithm and good convergence, but it takes too long calculation time. So we reduce 6 nonlinear kinematic equations to 3 polynomials using Nairs method and 3 polynomials to 2 polynomials. Then Newton-Raphson method is used to solve 3 polynomials and 2 polynomials respectively. We investigate operation counts and performance of three methods which come from the equation reduction and Newton-Raphson method, and choose the best method.