Se-Han Lee

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In this research a computer simulation for implementing attitude controller of wheeled inverted pendulum is carried out. The wheeled inverted pendulum is a kind of an inverted pendulum that has two equivalent points. In order to keep the naturally unstable equivalent point, it should be controlling the wheels persistently. Dynamic equations of the wheeled(More)
Configuration-dependent nonlinear coefficient matrices in the dynamic equation of a robot manipulator impose computational burden in real-time implementation of tracking control based on the inverse dynamics controller (IDC). However, parallel manipulators such as a Stewart platform have relatively small workspace compared to serial manipulators. Based on(More)
The solvation free energy density (SFED) model was modified to extend its applicability and predictability. The parametrization process was performed with a large, diverse set of solvation free energies that included highly polar and ionic molecules. The mean absolute error for 1200 solvation free energies of the 379 neutral molecules in 9 organic solvents(More)
In this research, dynamic equations a WIP (Wheeled Inverted Pendulum) changing center of gravity when some load or equipment on the WIP are changing. The WIP becomes a popular platform for mobile robots which should be equipping various load and apparatus on it. The WIP generally has two equilibrium points which are stable and unstable. The WIP should be(More)
During the last decades, the automation for constructing a steel structure has been extensively studied. However, the bolting process is still remained as a manual work, and the human workers climbs the vertical steel beams on top of the high-rise steel structure in many construction fields. The manual bolting process is extremely dangerous and inefficient.(More)
This paper describes the formulation of the obstacle avoidance method to work in three-dimensional workspaces. We assume a spherical and omni-directional robot. The obstacle information is given in the form of points, which is the usual form in which sensor data is given. Obstacle avoidance methods are based on a real-time control process. Sensors collect(More)
We developed surface grid-based solvation free energy density (Surface-SFED) models for 36 commonly used polar solvents. The parametrization was performed with a large and diverse set of experimental solvation free energies mainly consisting of combinations of polar solvent and multipolar solute. Therefore, the contribution of hydrogen bonds was dominant in(More)
BACKGROUND Different postural positions can be characterized by the activation and relative contributions of different postural muscles, and may variously contribute to the recovery from or worsening of chronic lower back pain. OBJECTIVE The present study aimed to investigates trunk muscle activities in four types of seated postures: cross-legged, long,(More)