• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.945-946
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• 2012

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.66-72
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• 2000

As the demand for the design of modular manipulators or special purpose manipulators has increased, task based design to design an optimal manipulator for a given task become more and more important. However, the complexity with a large number of design parameters, and highly nonlinear and implicit functions are characteristics of a general manipulator design. To achieve the goal of task based design, it is necessary to develop a methodology to solve the complexity. This paper addresses how to determine the kinematic parameters of a two-degrees of freedom manipulator with parallelogram five-bar link mechanism from a given task, namely, how to map a given task into the kinematic parameters. With simplified example of designing a manipulator with five-bar link mechanism, the methodology for task based design is presented. And it introduces formulations of a given task and manipulator specifications, and presents a new dexterity measure for manipulator design. Also the optimization problem with constraints is solved by using a genetic algorithm that provides robust search in complex spaces.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.3
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• pp.64-71
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• 1999

In this paper, two degree of freedom parallelogram link mechanism is used as DD(Direct-drive) robot mechanism. In parallelogram link mechanism, two motors being established in each base frame, the mass of motor itself is not loaded to anther motor; the number of links are increased, the mass of arm being lighter; with the estabilishment of link parameter, nonlinearity such as the centrifugal force disappears; at the same time anti-interference between motors can be realized. And to realize highy-accurate drive of parallelogram link DD robot manipulator, to improve the learning speed through the design of leaning control system using neural network, to raise adapting power to the varied work objects; the learning control algorithm is composed of neural network and feedback controller in this paper.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.5 s.122
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• pp.415-426
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• 2007

In a link motion punch press, numerous links are interconnected and each link executes a constrained motion at high speed. As a consequence, dynamic unbalance force and moment are transmitted to the main frame of the press, which results in unwanted vibration. This degrades productivity and precise stamping work of the press. This paper presents an effective method for reducing dynamic unbalance in a link motion punch press based upon kinematic and dynamic analyses. Firstly, the kinematic analysis is carried out in order to understand the fundamental characteristics of the link motion mechanism. Then design variable approach is presented in order to automate the model setup for the mechanism whenever design changes are necessary. To obtain the inertia properties of the links such as mass, mass moment of inertia, and the center of mass, 3-dimensional CAD software was utilized. Dynamic simulations were carried out for various combinations of design changes on some links having significant influences on kinematic and dynamic behavior of the mechanism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.296-301
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• 1998

In this experiments of design, vibration evaluation, and test of vehicles, aircraft, and other mechanisms the development of vibration simulator that serves environment similar to real fields takes lots of advantages. Especially, in the real field test of vehicles it possesses the advantages of showing the dynamic characteristics of the vehicle. In this study, to investigate the validity and fitness of proposed 6DOF parallel link mechanism we simulated that mechanism.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.92.1-92
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• 2002

$\textbullet$ A compact and robust wall-climbing robot, called MRWALLSPECT-II, is developed. $\textbullet$ The robot is a self-contained system for scanning external surfaces of gas or oil tank. $\textbullet$ The robot has advantages of reduced actuators, parts and easy control. $\textbullet$ The mechanism of the robot employs a closed link mechanism. $\textbullet$ Self-Contained, Wall-Climbing, MRWALLSPECT

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.8
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• pp.45-55
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• 1997

To design a ATM Switch which ahs advantages in high sped packet switching, it is essential to set multiple paths between input ports and output ports and to design a new packet transfer technique on that paths for decreasing Packet Loss by conflicts in internal Switch Plane. We propose new packet transfer method, Alternate Path Transfer Mechanism by Dynamic Bypass Transfer Method which can solve conflict problem in Banyan network easily. Proposed ATM Switch consists of Banyan networks, Input/Ouput Port, Bypass Link, and Bypass Link Controller. Packets caused conflicts in SEs have another chances of packet transfer over alternate switching planes by using this mechanism.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3131-3149
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• 2016

In-band Full-duplex (IBFD) wireless communication allows improved throughput for wireless networks. The current Half-duplex (HD) medium access mechanism Request to Send/Clear to Send (RTS/CTS) has been directly applied to IBFD wireless networks. However, this is only able to support a symmetric dual link, and does not provide the full advantages of IBFD. To increase network throughput in a superior way to the HD mechanism, a novel three-way handshaking access mechanism RTS/SRTS (Second Request to Send)/CTS is proposed for point to multipoint (PMP) IBFD wireless networks, which can support both symmetric dual link and asymmetric dual link communication. In this approach, IBFD wireless communication only requires one channel access for two-way simultaneous packet transmissions. We first describe the RTS/SRTS/CTS mechanism and the symmetric/asymmetric dual link transmission procedure and then provide a theoretical analysis of network throughput and delay using a Markov model. Using simulations, we demonstrate that the RTS/SRTS/CTS access mechanism shows improved performance relative to that of the RTS/CTS HD access mechanism.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.11
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• pp.1033-1038
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• 2000

The unbalanced heavy-loaded elevation-drive system is composed of a hydraulic cylinder, a driving link-mechanism and an equilibrating-mechanism which compensate the static unbalanced moment of the elevation load. The Compensator for the unbalanced moment is composed of a hydrau-pneumatic accumulator and a hydraulic cylinder which act with the elevation cylinder together. Compensation of the variable static-unbalanced moment for the elevation-drive system is very difficult because these mechanisms imply highly nonlinear properties due to air conditioning characteristics and mechanical rotation of the link-mechanism. In this study, through the analysis of the already designed equilibrating-mechanism, the optimal design parameters of the equilibrating-mechanism is suggested.

• Journal of Communications and Networks
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• v.8 no.4
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• pp.391-400
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• 2006

With the on-going wireless access technologies, the Internet has become accessible anytime anywhere. In wireless networks, link errors significantly degrade the performance of the transmission control protocol (TCP). To cope with this issue, this paper improves the recently-proposed terrestrial REFWA (T-REFWA) scheme by adding a new error recovery mechanism to its original design. In the T-REFWA scheme, senders are acknowledged with appropriate sending rates at which an efficient and fair utilization of network resources can be achieved. As the feedback values are computed independently of link errors, senders can keep transmitting data at high rates even in case of link error occurrences. Using this feature, the proposed error recovery mechanism can achieve high throughput in environments with high bit error rates. The throughput is further improved by disabling the exponential back-off algorithm of TCP so that long idle times are avoided in case of link errors. We show through simulations that the proposed method improves TCP performance in high bit error rates. Compared with several TCP variants, the proposed error recovery scheme exhibits higher link utilization and guarantees system fairness for different bit error rates.