• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.427-427
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• 2000

In this study, singularity of two types of mobile robots for various input joints are investigated: One is the mobile robot with three caster wheels and the other is the mobile robot with two conventional wheels and one caster wheel. Kinematic models are derived via the transfer method of generalized coordinates. Then, determinants of the Jacobian of the mobile robots are used to identify the singularity configurations.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.9-18
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• 2017

Objective: The purpose of this study was to identify kinematic variables that govern successful performance and judges' scores and to establish correlative relationships among those of Yurchenko layout with a full twist in female vaults. Method: Four video cameras with sampling rate of 60 Hz collected 32 motion data of Yurchenko vaults from twenty-two female participants (age: $18.6{\pm}3.6years$, height: $153.0{\pm}6.5cm$, mass: $44.7{\pm}7.3kg$) during national competition. Posting processing and calculations of kinematic variables were performed in Kwon 3D XP and $Matlab^{(R)}$ programs. Correlation and regression analyses were applied to find the relationships between the obtained scores and kinematic variables. Deterministic model (Hay & Reid, 1988) was used to investigate the strength of correlative relationships among kinematic variables. Results: The obtained scores from the judges' decision were mainly affected by post-flight peak height, horse contact time, knee angle at landing, and horse takeoff angle. Strong blocking during horse contact was required to get successful performance and obtain high scores. Modified deterministic model showed that round-off entrance and takeoff angles and resultant velocity of the center of mass (CM) during the roundoff phase were the starting variables affecting performance in the following kinematics. Knee angle at landing, a highly influential variable on the obtained point, was only determined by judges' decision without significant correlative relationship with previous kinematic variables. Conclusion: The obtained scores highly depended on kinematic variables of post-flight and horse contact phases that were affected by those from the previous phases including round-off postures and resultant velocity of the body center of mass.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.1
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• pp.63-72
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• 2003

A new 6-DOF parallel haptic device is proposed. Many existing haptic devices require large power due to having floating actuator and also have small workspaces. The proposed new mechanism can generate 6-DOF reflecting force. This device is relatively light by employing non-floating actuators and has large workspace. Kinematic analysis and kinematic optimal design is performed for this mechanism. Dexterous workspace, global isotropic index, and global maximum force transmission ratio are considered as kinematic design indices. To deal with such multi-criteria optimization problem. composite design index is employed. For the given operational specifications, actuator sizing for this mechanism is also carried out.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.48-58
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• 1989

An assembly modeling system, with which a designer can interactively create an assembly of components ready for the dynamic analysis, has been developed. In this system, an assembly model is created from the mating conditions between the components in the assembly, and then most information required for the dynamic or kinematic analysis packages are derived. For this development, the following problems have been solved; the creation of assembly data structure, the derivation of the joint information, the inference of each component's position, and the creation of the joint coordinate systems. Through this work, the designer can easily model an assembly by assigning mating conditions, and check the dynamic or kinematic performance with the automatic creation of inputs for the assembly analysis packages.

• Korean Journal of Applied Biomechanics
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• v.28 no.3
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• pp.159-164
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• 2018

Objective: The aims of this study were to determine the impact peak force and kinematic variables in running speed and investigate the relationship between them. Method: Thirty-nine male heel strike runners ($mean\;age=21.7{\pm}1.6y$, $mean\;mass=72.5{\pm}8.7kg$, $mean\;height=176.6{\pm}6.1cm$) were recruited in this investigation. The impact peak forces during treadmill running were assessed, and the kinematic variables were computed using three-dimensional data collected using eight infrared cameras (Oqus 300, Qualisys, Sweden). One-way analysis of variance ANOVAwas used to investigate the influence of the running speed on the parameters, and Pearson's partial correlation was used to investigate the relationship between the impact peak force and kinematic variables. Results: The running speed affected the impact peak force, stride length, stride frequency, and kinematic variables during the stride phase and the foot angle at heel contact; however, it did not affect the ankle and knee joint angles in the sagittal plane at heel contact. No significant correlation was noted between the impact peak force and kinematic variables in constantrunning speed. Conclusion: Increasing ankle and knee joint angles at heel contact may not be related to the mechanism behind reducing the impact peak force during treadmill running at constant speed.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1779-1784
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• 2010

Since PSD(Platform Screen Door) is set up at many subway stations, its design related to a safety becomes gradually important. Especially the intereference check with a running railway vehicle is the most important of performance indices. This study proposes a dynamic analysis models for the railway vehicle and rail. Some design parameters are considered in the models to find a correlation to the performance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.102-109
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• 1986

Based on the Hartenberg-Denavit symbolic equation, which is one of equations for the kinematic analysis of three dimensional (3-D) linkage, a generalized kinematic motion equation is derived utilizing Euler angles and employing the coordinates transformation. The derived equation can feasibly be used for the motion analysis of any type of 3-D linkages as well as 2-D ones. In order to simulate the general motion of 3-D linkgages on digital computer, the generalized equation is programmed through the process of numerical analysis after converting the equation to the type of Newton-Raphson formula and denoting it in matrix form. The feasibility of theoretically derived equation is experimentally proved by comparing the results from the computer with those from experimental setup of three differrent but generally empolyed 3-D linkages.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.621-625
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• 2005

This paper presents a new hybrid serial-parallel robot(HSPR), which has six degrees of freedom driven by ball screw linear actuators and motored joints. This hybrid robot design presents a compromise between high rigidity of fully parallel manipulators and extended workspace of serial manipulators. The hybrid robot has a large, singularity-free workspace and high stiffness. Therefore, the presented kinematic structure of the hybrid robot is particularly suitable for multi-tasking machining processes such as milling, drilling, deburring and grinding. In addition to the machining processes, the hybrid robot can be used for welding, fixturing, material handling and so on. The study on design of the hybrid robot is performed. A kinematic analysis and mechanism description of the hybrid robot with six-controlled degree of freedom is presented. In the virtual design works by DADS, workspace and force analysis are discussed. A numerical model is treated to demonstrate our analysis and to determine the range of permissible extension of the struts. Also, we determine some important design parameters for the hybrid robot.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.176-187
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• 2005

This paper presents an evaluation of joint configurations of a robotic finger based on kinematic analysis. The evaluation is based on an assumption that the current control methods for the fingers require that the contact state specified by the motion planner be maintained during manipulation. Various finger-joint configurations have been evaluated for different contact motions. In the kinematic analysis, the surface of the manipulated object was represented by B-spline surface and the surface of the finger was represented by cylinders and a half ellipsoid. Three types of contact motion, namely, 1) pure rolling, 2) twist-roiling, and 3) slide-twist-rolling are assumed in this analysis. The finger-joint configuration best suited for manipulative motion is determined by the dimension of manipulation workspace. The evaluation has shown that the human-like fingers are suitable for maintaining twist-rolling and slide-twist-rolling but not for pure rolling. A finger with roll joint at its fingertip link, which is different from human fingers, proved to be better for pure rolling motion because it can accommodate sideway motions of the object. Several kinds of useful finger-joint configurations suited for manipulating objects by fingertip surface are proposed.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.1
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• pp.8-14
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• 2020

The implosion phenomena of pressure vessels operating in deep water under extremely high external pressure have been well known. The drastic energy release to ambient field in the form of pressure pulse is accompanied with catastrophic collapse of shell structure. Such a proximity shock wave could be a serious threat to the structural integrity of adjacent submerged body and several suspected accidents have been reported. In this study, basic research for the occurrence and development of shock wave due to implosion was carried out. The mechanism of pressure pulse generation and energy dissipation were investigated, and a simplified kinematic model to approximate the collapse modes of circular tubes which can be generated by external pressure and implosion was examined. Using the simplified kinematic model, the process of energy dissipation was formulated, and the magnitude of released pressure shock wave was estimated quantitatively. To investigate the validity of developed kinematic model and shock wave estimation process, the results from a nonlinear FE analysis code and collapse test carried out using pressure chamber were compared with the results from the developed kinematic model.