• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.723-729
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• 2012

Spring-like leg models have been employed to explain various dynamic characteristics in human walking. However, this leg stiffness model has limitations to represent complex motion of actual human gait, especially the behaviors of each lower limb joint. The purpose of this research was to determine changes of total leg stiffness and lower limb joint stiffness with gait speed in knee osteoarthritis. Joint stiffness defined as the ratio of the joint torque change to the angular displacement change. Eight subjects with knee osteoarthritis participated to this study. The subject walked on a 12 m long and 1 m wide walkway with three sets of four different randomly ordered gait speeds, ranging from their self-selected speed to maximum speed. Kinetic and kinematic data were measured using three force plates and an optical marker system, respectively. Joint torques of lower limb joints calculated by a multi-segment inverse dynamics model. Total leg and each lower limb joint had constant stiffness during single support phase. The leg and hip joint stiffness increased with gait speed. The correlation between knee joint angles and torques had significant changed by the degree of severity of knee osteoarthritis.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1158-1161
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• 2004

This paper describes the construction of a half sphere screen driving tilting simulator that can perform six degree-of-freedom (DOF) motions simulator to a tilting train. The mathematical equations of Tilting Train dynamics are first derived from the 6-DOF bicycle model and incorporated with the bogie, carbody, and suspension subsystems. The equations of motion are then programmed by visual C++ code. To achieve the simulator functions, a motion platform that is constructed by six electric-driven actuators is designed, and its kinetics/inverse kinetics analysis is also conducted. Driver operation signals such as carbady angle, accelerator, and tilting positions are measured to trigger the Tilting dynamics calculation and further actuate the cylinders by the motion platform control program. In addition, a digital PID controller is added to achieve the stable and accurate displacements of the motion platform. The experiments prove that the designed simulator is adequate in performing some special rail road driving situations discussed in this paper.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.711-716
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• 2003

This paper presents the inverse dynamic analysis of the hydraulic excavator manipulator based on the experimental data. A three dimensional rigid multi-body model of the hydraulic excavator manipulator was built up. Inverse dynamic analysis for typical operation mode was carried out by the ADAMS program. In order to verify the analysis results with the measured, the hydraulic pressure and displacement of the cylinders were measured and the dynamic analysis was carried out using experimental data. From the results of the cylinder driving forces, good agreements are obtained between the analysis and the measurement.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1774-1779
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• 2014

It is known that muscle strength of human body can alter or deteriorate as aging. In this study, we present an inverse dynamics simulation to investigate the effect of muscle strength on performing the daily activities. A 3D musculoskeletal model developed in this study includes several segments of whole body, long and short muscles, ligaments and disc stiffness. Five daily activities such as standing, flexion, finger tip to floor, standing lift close and lifting flexed were simulated with varying the maximum muscle force capacities (MFC) of each muscle fascicles from 30 to $90N/cm^2$ with an increment of $30N/cm^2$. In the result, no solution can be obtained for finger tip to floor and lifting flexed with $30N/cm^2$. Even though the solution was available for standing lift close activity in case of $30N/cm^2$ capacity, many of muscle fascicles hit the upper bound of muscle strength which means that it is not physiologically possible to perform the acvities in reality. For lifing flexed, even the case of $60N/cm^2$ capaciy, represents the moderate healthy people, was not able to find the solutions, showing that 18 muscles among 258 muscle fascicles reached 100% of muscle capacity. The estimated results imply that people who have low muscle strength such as elders or rehabilitation patients were required higher muscle work to perform and maintain the same daily activities than healthy one.

• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.30-40
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• 1995

In this paper, it is proposed a robust control scheme for real time control of a robot manipulator with parameter uncertainties. The focus of this paper is a new approach of multivariable control schemes for an assembly robot manipulator to achieve the accurate trajectory tracking by joint angles. The proposed control scheme consists of a multivariable feedforward controller and feedback controller. In this control scheme, the feedback controller consists of proportional-derivative type and is designed by the pole placement method. The feedforward controller uses the inverse of the linealized model of robot manipulator dynamics. This feedback controller ensures that each joint enables to track any reference trajectory. The proposed robot controller scheme has a computational efficiency.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.444-451
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• 2005

The analysis of human arm motion during steering maneuver is carried out for investigation of man-machine interface of driver and steering system Each arm is modeled as interconnection of upper arm, lower arm, and hand by rotational joints that can properly represents permissible joint motion, and both arms are connected to a steering wheel through spring and damper at the contact points. The joint motion law during steering motion is determined through the measurement of each arm movement, and subsequent inverse kinematic analysis. Combining the joint motion law and inverse dynamic analysis, joint stiffness of arm is estimated. Arm dynamic analysis model for steering maneuver is setup, and is validated through the comparison with experimentally measured data, which shows relatively good agreement. To demonstrate the usefulness of the arm model, it is applied to study the effect of steering column angle on the steering motion.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.724-727
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• 1997

In this paper, we developed a Windows 95 version Off-Line Programming System which can simulate a Robot model in 3D Graphic space. 4 axes SCARA Robot (especially FARA SM5)was adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed program. The interface between users and the OLP system in the Windows 95's GUI environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.227-232
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• 1998

We developed a Off-Line Graphic Simulator which can simulate a robot model in 3D graphics space in Windows 95 version. 4 axes SCARA robot was adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed program. The interface between users and the off-line program system in the Windows 95's graphic user interface environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D graphics.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.565-570
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• 1999

In this paper, we developed a windows 95 version Off-Line Programming system which can simulate a Robot model in 3D Graphics space. 4axes SCARA Robot (especially FARA SM5) was adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed program. The interface between users and the OLP system in the Windows 95's GUI environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by silicon Graphics, Inc. were utilized for 3D Graphics.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.11
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• pp.9-21
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• 2009

This paper proposes the alternative observer and controller design scheme based on T-S fuzzy model. Nonlinear systems are represented by fuzzy models since fuzzy logic systems are universal approximators. In order to estimate the unmeasurable states of a given unknown nonlinear system, T-S fuzzy modeling method is applied to get the dynamics of an observation system. T-S fuzzy system uses the linear combination of the input state variables and the modeling applications of them to various kinds of nonlinear systems can be found. The proposed indirect adaptive fuzzy observer based on T-S fuzzy model can cope with not only unknown states but also unknown parameters. The proposed controller is based on a simple output feedback method. Therefore, it solves the singularity problem, without any additional algorithm, which occurs in the inverse dynamics based on the feedback linearization method. The adaptive fuzzy scheme estimates the parameters and the feedback gain comprising the fuzzy model representing the observation system. In the process of deriving adaptive law, the Lyapunov theory and Lipchitz condition are used. To show the performance of the proposed observer and controller, they are applied to an inverted pendulum on a cart.