• International Journal of Control, Automation, and Systems
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• v.6 no.2
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• pp.223-233
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• 2008

A new output feedback controller design approach for flexible-joint (FJ) robots via the observer dynamic surface design technique is presented. The proposed approach only requires the feedback of position states. We first design an observer to estimate the link and actuator velocity information. Then, the link position tracking controller using the observer dynamic surface design procedure is developed. Therefore, the proposed controller can be simpler than the observer backstepping controller. From the Lyapunov stability analysis, it is shown that all signals in a closed-loop system are uniformly ultimately bounded. Finally, the simulation results of a three-link FJ robot are presented to validate the good position tracking performance of the proposed control system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.628-634
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• 1995

In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformer which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backash and friction. Therefore a dynamic modeling and stste sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensitivity snalysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensitivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design based on the results on the results of dynamic and state sensitivity.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.90-99
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• 1996

In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformed which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backlash and friction. Therefore a dynamic modeling and state sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensit- ivity analysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensit- ivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design and faster operating based on the results of dynamic and state sensitivity.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1646-1647
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• 2007

In the conventional sliding mode control(SMC), the states of controlled systems are linearly dependent because of the characteristic of the sliding surface. This means that conventional SMC can not add its robustness to other control methods. To overcome this problem, a special sliding surface with additional dynamic states has been proposed. However the additional dynamic states make it difficult to design a controller because the order ofa controller becomes higher. So, in this paper, a novel sliding surface design method, which does not require any additional dynamic state, is proposed. The relationships between the states with desirable responses can be expressed by using SVM and included in a sliding mode dynamics. The robust optimal controller with the optimal performanceand the robustness of SMC is considered.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.1871-1877
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• 1999

An optimal design method using a response surface method for dynamic characteristics of a washer is presented. The proposed method uses the design of experiment and a computer model is used for the experiment. The value of the cost function is estimated using a computer model for each case of the design variable variation. An orthogonal array is used to obtain best cases to be considered with minimum number of experimentation. Using these experimental values, optimal design is performed using a response surface method. The method used in this paper can be applied to any complicated mechanical systems that can be modelled and analyzed by a computer program. The method is applied to the design of dynamic characteristics of a washer.

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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• pp.54-60
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• 2006

For optimal design of a deep-sea ocean mining collector system, based on self-propelled mining vehicle, it is imperative to develop and validate the dynamic model of a tracked vehicle traveling on soft deep seabed. The purpose of this paper is to evaluate the fidelity of the dynamic simulation model by means of response surface methodology. Various statistical techniques related to response surface methodology, such as outlier analysis, detection of interaction effect, analysis of variance, inference of the significance of design variables, and global sensitivity analysis, are examined. To obtain a plausible response surface model, maximum entropy sampling is adopted. From statistical analysis and prediction for dynamic responses of the tracked vehicle, conclusions will be drawn about the accuracy of the dynamic model and the performance of the response surface model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1768-1771
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• 2003

Hard turning replaces grinding for finishing process with expectations of higher productivity and demanded surface quality. Especially for the surface roughness as surface quality demanded in finishing process of hard turning, know-how of machining characteristics of hardened materials by cutting force analysis should be accumulated in company with achievement of precision of elements and high stiffness design technology in hard turning. Considering chip formation mechanism of hardened materials, adequate cutting conditions are selected for machining experiments and cutting forces are measured according to cutting conditions. Increase of cutting forces especially thrust force and increase of dynamic instability could occur in hard turning. Analysis of dynamic characteristics of the cutting forces is executed to investigate relation between dynamic instability and surface roughness in hard turning. Investigation on effects of relative motion of machining system generated by vibration due to dynamic instability shows that ultimate surface roughness could be predicted considering relative motion of machining system with geometrical surface roughness.

• International Journal of Human Ecology
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• v.14 no.1
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• pp.41-55
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• 2013

The purpose of this study was to analyze human upper body surface changes at the shoulder and back area. The body surface data were analyzed in terms of muscle and bone displacement in dynamic postures. Body surface data were collected with a 3D body scanner. The body surface was scanned at the static and four baseball batting postures. The body surface dimensions over the deltoids, scapulae and trapezius were measured. The results show that the vertical measurements of the deltoids increased by 20%. The horizontal measurements of the axilla of the back increased. The surface of the trapezius was elongated by over 10%, and the lower back musculature was elongated by about 50%. The results of this study showed that changes in back body surface caused by upper arm movements. It was influenced by the deltoid articulated with the humeri and the scapulae and trapezius. These body surface changes caused by muscle activities and ranges of motion can be used to design functional clothing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1171-1178
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• 2011

This paper shows the robust design results of an actuator, a kind of dynamic system. Variations in the components comprising the actuator cause uncertainties in the system's dynamic performance. Therefore, a probabilistic design method is applied to ensure robust actuator performance to component variation. A Simulink model for the actuator was built using transfer functions for the components. The dynamic responses of the actuator were evaluated using the Simulink model. Performance indexes were approximated as quadratic functions of the design parameters through the application of the response surface methodology (RSM) with the Simulink model. Then, a probabilistic design method was applied to the approximated performance indexes to obtain optimal design parameters that would provide robust actuator performance. The optimal design was compared to the present design in terms of the performance indexes and dynamic response characteristics over time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2066-2072
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• 2010

In this paper, a variable structure dynamic output feedback controller with an transformed sliding surface is designed for the improved robust control of a uncertain system under unmatched system uncertainty, matched input matrix uncertainty, and disturbance satisfying some conditions. This paper is extended from the results of the static output feedback VSS in [9]. To effectively remove the reaching phase problems, an initial condition of the dynamic output is determined. The previous some limitations on the dynamic output feedback variable structure controller is overcome in this systematic design. A stabilizing control is designed to generate the sliding mode on the predetermined sliding surface S=0 and as a results the closed loop exponential stability is obtained and proved together with the existence condition of the sliding mode on S=0 for all unmatched system matrix uncertainties. To show the usefulness of the algorithm, a design example and computer simulations are presented.