• Journal of the Society of Naval Architects of Korea
• /
• v.41 no.2
• /
• pp.90-97
• /
• 2004

Flow mechanism of contractive and dilative motion is numerically investigated to obtain a propulsive force in highly viscous fluid. An axisymmetric code is developed with unstructured grid system based on cell-centered scheme. It is validated by comparing with the results of Stokes approximation for the problem of uniform flow past a sphere in low Reynolds number(R$_{n}$=1). The validated code is applied to the simulation of contractive and dilative periodic motion of body whose results are quantitatively compared with the two dimensional case. In order to investigate the grid dependency, two different grids are applied to the present computations. The present study provides key information for the development of an axisymmetric Micro-hydro-robot.t.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.6
• /
• pp.1235-1241
• /
• 2012

In this paper, each driving motor for leg joints on a robot is controlled by estimating the direction of the legs measuring each joint angle and attitude angle of robot. We used quadruped working robot named TITAN-VIII in order to carry out this experimental study. 4 load cells are installed under the bottom of 4 legs to measure the pressed force on each leg while it's walking. The walking experiments of the robot were performed in 8 different conditions combined with duty factor, the length of a stride, the trajectory height of the foot and walking period of robot. The validity of attitude control for quadruped walking robot is evaluated by comparing the pressed force on a leg and the power consumption of joint driving motor. As a result, it was confirmed that the slip-condition of which the foot leave the ground late at the beginning of new period of the robot during walking process, which means the attitude control of the robot during walking process wasn't perfect only by measuring joint and attitude angle for estimating the direction of the foot.

• Journal of KIISE:Software and Applications
• /
• v.34 no.8
• /
• pp.731-742
• /
• 2007

Self-growing software is a software system that has the capability of evolving its functionalities and configurations by itself based on dynamically monitored situations. Self-growing software is especially necessary for intelligent service robots, which must have the capability to monitor their surrounding environments and provide appropriate behaviors for human users. However, it is hard to anticipate all situations that robots face with, and it is hard to make robots have all functionalities for various environments. In addition, robots have limited internal capacity. To support self-growing software for intelligent service robots, we are developing a cell-based distributed repository system that allows robots and developers transparently to share robot functionalities. To accomplish the creation of evolutionary repositories, we invented the concept of a cell, which is a logical group of distributed repositories based upon the functionalities of components. In addition, a cell can be used as a unit for the evolutionary growth of the components within the repositories. In this paper, we describe the requirements and architecture of the cell-based repository system for self-growing software. We also present a prototype implementation and experiment of the repository system. Through the cell-based repositories, we achieve improved performance of self-growing actions for robots and efficient sharing of components among robots and developers.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.11B
• /
• pp.1030-1037
• /
• 2008

This paper presents an algorithm for the path-finding problem in unknown environments with cooperative and commutative multi-robots. To verify the algorithm, we investigate the problem of escaping through the exit of a randomly generated maze by muti-robots. For the purpose, we adopt the so called frontier cells and cell utility functions, which were used in the exploration problem for the multi-robots. For the wireless communications among the mobile robots, we modify and utilize the so called the random basket routing, a kind of hop-by-hop opportunistic routing. A mobile robot, once it finds the exit, will choose its next action, either escape immediately or stay-and-relay the exit information for the others, where the robot takes one action based on a given probability. We investigate the optimal probability that minimizes the average escaping time (out of the maze to the exit) of a mobile robot.

• 제어로봇시스템학회:학술대회논문집
• /
• 1988.10a
• /
• pp.364-369
• /
• 1988

In this study, a model for the simulation of the material flow not only inside a robot cell with flexible handling sequence but also between robot cells is presented. A method for the connection of special simulation programs has been developed and a logic model between a real system and a simulation system is employed.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.6 s.177
• /
• pp.1379-1389
• /
• 2000

In this study, a design process of robotic cell is presented. This paper focuses only on the automation of workpiece handling with robot. The presented design process enables us to analyze effectiv ely the original production system and to redesign it as an optimum production system with robots. An original production system is analyzed with respect to its economical and technological requirements for automation. If automation of the given production system is feasible, the conceptual design for automation is firstly derived. Next, the detail design is derived for the optimum conceptual design. Finally, an optimum system solution is determined after the economical and technical evaluation of all the derived detail designs. The all specifications of each element of the redesigned production system and its layout are determined at the detail design phase. This paper shows a low cost supporting tool for layout design of robotic cell with SCARA type robots.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.386-386
• /
• 2000

Cell mapping is a powerful computational technique for analyzing the global behavior of nonlinear dynamic systems. It simplifies the task of analyzing a continuous phase space by partitioning it into a finite number of disjoint cells and approximating system trajectories as cell transitions. A cell map for the system is then constructed based on the allowable control actions. Next search algorithms are employed to identify the optimal or near-optimal sequence(s) of control actions required to drive the system from each cell to the target cell by an "unravelling algorithm." Errors resulting from the cell center-point approximation could be reduced and eliminated by fuzzifying the bonders of cells. The dynamic system control method based on the cell mapping has been demonstrated for a motor control problem.l problem.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.11a
• /
• pp.179-180
• /
• 2010

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.9
• /
• pp.909-913
• /
• 2013

Various types of large substrate handling robots are used in the thin file solar cell manufacturing line as well as LCD or PDP production line. Because the robot handles the heavy substrate at high speed, there are some issues such as vibration control and the optimal design of arms and forks. As the substrate becomes larger and heavier, robot systems are also larger and the vibration issue of the robot end-effector becomes more important. In the paper, we established the robot modeling and the control architecture including the flexible part such as forks. Then, we performed dynamic simulation in the various condition and analyzed the characteristics of the fork vibration. We can reduce the vibration using the trajectory planning and input shaping algorithm and it was proved by experiment.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.89-92
• /
• 1997

The objective of this paper is to provide an alternative framework for the integration of process planning and scheduling in cellular manufacturing. The concept of an integrated cellular manufacturing system is defined and the system architecture is presented. In an integrated cellular manufacturing system, there are three modules : the process planning module, the manufacturing-cell design module, and the cell-scheduling module. For each module, the tasks and their activities are explained.