• 대한기계학회논문집A
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• 제20권11호
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• pp.3398-3407
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• 1996

In this paper, we derive an algorithm and develope a computer program which analyze rapidly and precisely the inverse kinematics of robotic mechanism with spatial complex chain structure based on the relative coordinates. We represent the inverse kinematic problem as an optimization problem with the kinematic constraint equations. The inverse kinematic analysis algorithm, therefore, consists of two algorithms, the main, an optimization algorithm finding the motion of independent joints from that of an end-effector and the sub, a forward kinematic analysis algorithm computing the motion of dependent joints. We accomplish simulations for the investigation upon the accuracy and efficiency of the algorithm.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.58-63
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• 2007

We developed a new algorithm for jointly inverting dc resistivity and seismic travel time tomography data based on the multiple constraints: (1) structural similarity based on cross-gradient, (2) correlation between two different material properties, and (3) a priori information on the material property distribution. Through the numerical experiments of surface dc resistivity and seismic refraction surveys, the performance of the proposed algorithm was demonstrated and the effects of different regularizations were analyzed.

• ETRI Journal
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• 제37권5호
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• pp.898-905
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• 2015

In this paper, we consider a joint beamforming and jamming design to enhance physical layer security against potential multiple eavesdroppers in a multiple-input and single-output cellular broadcast channel. With perfect channel state information at the base station, we propose various design approaches to improve the secrecy of the target user. Among the proposed approaches, the combined beamforming of maximum ratio transmission and zero-forcing transmission with a combination of maximum ratio jamming and zero-forcing jamming (MRT + ZFT with MRJ + ZFJ) shows the best security performance because it utilizes the full transmit antenna dimensions for beamforming and jamming with an efficient power allocation. The simulation results show that the secrecy rate of this particular proposed approach is better than the rates of the considered conventional approaches with quality-of-service and outage probability constraints.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.870-874
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• 2004

This paper presents a three dimensional modeling and simulations of operation and running of a wheel loader using the ADAMS program. A wheel loader consists of a bucket, a boom, a crank, a front frame, a rear frame, a bucket cylinder, two boom cylinders, two steering cylinders, nine spherical joints, six universal joints, five translation joints, three inline joints, a revolute and a fixed joint. Judging from the actual degrees of freedom of the wheel loader, proper kinematic joints are selected to exclude redundant constraints in the modeling. Through the running simulation over a bump with the three dimensional modeling, the joint reaction forces are calculated.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.831-834
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• 2000

The sign-language tan be used a9 an auxiliary communication means between avatars of different languages. At that time an intelligent communication method can be also utilized to achieve real-time communication, where intelligently coded data (joint angles for arm gestures and action units for facial emotions) are transmitted instead of real pictures. In this paper we design a gesture-emotion keyframe editor to provide the means to get easily the parameter values. To calculate both joint angles of the arms and the hands and to goner-ate the in keyframes realistically, a transformation matrix of inverse kinematics and some kinds of constraints are applied. Also, to edit emotional expressions efficiently, a comic-style facial model having only eyebrows, eyes nose, and mouth is employed. Experimental results show a possibility that the editor could be used for intelligent sign-language image communications between different lan-guages.

• 한국소음진동공학회논문집
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• 제12권12호
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• pp.929-934
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• 2002

This paper considers the vibration Problem of vehicle driveline which consists of two propeller shafts and the center bearing. The excessive vibration occurs at the center bearing when the vehicle starts to run. Using the kinematic constraints at the universal joint between two propeller shafts, we developed an one d.o.f model which describes the radial motion of the center bearing. We found out that the vibration occurs at the specific vehicle speed corresponding to the natural frequency of the model. Comparing the simulation results with test results we also show that the vibration at low vehicle speed is caused primarily by the feint angle and secondarily by the mis-aligned yoke flange rather than by the unbalance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2709-2712
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• 2003

In this paper, dynamic constraints are considered for the analysis of manipulability of robotics systems comprised of two cooperating arms. Given bounds on the torques of joint actuators for each robot, the purpose of this study is to derive the bounds of task acceleration of object carried by the system. Under the assumption of complete constraint contact, a set of examplar polytope describing acceleration bounds of two cooperating robots are included.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.990-995
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• 1991

The integration of intelligent robots into manufacturing systems should positively impact the product quality and productivity. A new theory of object location and recognition using the supporting plane is presented. The unknown supporting points are determined by image coordinates, known camera parameters, and joint coordinates of the robot manipulators. This is developed by using the geometrical interpretation of perspective projection and the geometrical constraints of industrial environments. This can be applied to solve typical robot vision problems such as determination of position, orientation, and recognition of objects.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.154-159
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• 1989

This paper presents a motion planning algorithm for conveyor tracking. We formulate the problem as the linear quadratic tracking problem in optimal control theory and solve it through dynamic programming. In the proposed algorithm, the steady-state tracking error is eliminated completely, and the joint torque, velocity, acceleration, and jerks are considered as some constraints. Numerical examples are then presented to demonstrate the utility of the proposed motion planning algorithm.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.48-53
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• 2004

In this paper, the task-oriented optimal configuration in the sense of Velocity and Force manipulability measure of manipulator mounted on ROV is considered. Manipulability is a quantitative measure of manipulator's capability obtained under the limits of joint velocities or torques. The base arrangements and optimal joint configuration of manipulator, that maximize the manipulability measure under the constraints of given task, are investigated. With the two types of base arrangements of manipulator, workspace analysis is carried out to investigate merits and demerits of each arrangement on the view of manipulability measure. To find optimal joint configuration for a given task with each arrangement, the SQP(Sequential Quadratic Programming) optimization are performed. Weighted linear combination of velocity and force manipulability measure is object function for SQP optimization. The kinematic parameters of Dual Orion manipulator which will be mounted on KORDI ROV are used for simulation.