• International Journal of Precision Engineering and Manufacturing
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• v.2 no.4
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• pp.75-80
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• 2001

An error analysis is very important to estimate performance of a precision machine. This study proposes an error analysis for a new parallel device, a cubic parallel device. The cubic parallel manipulator has error sources including upper and lower universal joint errors due to the directional changes in the link and actuation errors. The maximum errors of the end effector are affected by the axial direction changes of each links and the clearances of the universal joints when the parallel manipulator is moving along a path. It is found that the changes of errors mostly occur at the positions where the directions of exerting link forces shift. The error analysis is based on an error model formed from the relation between the universal point errors and the end-effector accuracy. The analysis method can be also used in predicting the accuracy of other parallel devices.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.227-230
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• 2002

In this paper we concentrate on overall direction of the gaze based on a head pose for human computer interaction. To decide a gaze direction of user in a image, it is important to pick up facial feature exactly. For this, we binarize the input image and search two eyes and the mouth through the similarity of each block ( aspect ratio, size, and average gray value ) and geometric information of face at the binarized image. We create a imaginary plane on the line made by features of the real face and the pin hole of the camera to decide the head orientation. We call it the virtual facial plane. The position of a virtual facial plane is estimated through projected facial feature on the image plane. We find a gaze direction using the surface normal vector of the virtual facial plane. This study using popular PC camera will contribute practical usage of gaze tracking technology.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.374-382
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• 2007

Robot mobility and intelligence become more important for robots to be used in various fields other than automation. The main purpose of providing mobility to a robot is to extend the robot's manipulability. In this paper, we introduce a small humanoid robot that can autonomously play golf as an example of incorporating robot intelligence, mobility, and manipulability. The robot has 12 degrees of freedom for legs and has various basic walking patterns. It can move to a desired position and change orientation by combining the basic waking patterns. The robot has a color CCD camera and can extract coordinates of the objects in the environments. The small humanoid robot has 8 degrees of freedom for arms and can play golf autonomously with two kinds of dexterous swing motions. Kinematic analysis of the robot arms, vision data processing for the recognition of the environments, algorithm for playing robotic golf have been performed or proposed. The experimental results show that the robot can play golf autonomously.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.231-233
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• 2007

In this paper we present a new visual approach for the robust bin-picking in a two-step concept for a vision driven automatic handling robot. The technology described here is based on two types of sensors: 3D laser scanner and CCD video camera. The geometry and pose(position and orientation) information of bin contents was reconstructed from the camera and laser sensor. these information can be employed to guide the robotic arm. A new thinning algorithm and constrained hough transform method is also explained in this paper. Consequently, the developed bin-picking demonstrate the successful operation with 3D hole object.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.539-539
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• 2000

This paper shows how to implement force reflection for a needle insertion problem. The target is a needle spine biopsy simulator for tumor inspection by needle insertion. Simulated force is calculated from the relationship of volume graphic data and the orientation and Position of the needle, and it is generated using PHANTOM$^{TM}$. To generate realistic force reflection, the directional force of the needle has been generated by tissue model. The other rotational force is generated using a pivot to keep the needle in the initial inserted direction after puncturing the skin. Since the used haptic device has limitation for generating high stiffness and large damping, scale downed model and digital filter are used to stabilize the system.m.

• Korean Journal of Computational Design and Engineering
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• v.13 no.5
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• pp.391-402
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• 2008

Today's product development environment is characterized as abrupt changes in consumer needs and short lifecycle of the product, which requires manufacturing companies to be equipped with time-to-market and time-to-volume strategies as prime factors for the successful product launch on market. They especially need to bring a product to the market faster with smart methodologies that enable assembly manufacturers to efficiently simulate and manage part assembly information throughout product development process. The research in this paper provides n e-manufacturing methodology considering geometric constraints in order to decide assembly process sequences. The methodology organizies the part layout (position & orientation) in order to optimize human postures during the assembly processes. As the case studies, assembly parts for two commercial products have been generated as CAD models and analyzed for the desired solutions for part assembly sequences using the proposed methodology.

• International Journal of Control, Automation, and Systems
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• v.2 no.4
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• pp.536-541
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• 2004

It is important to estimate and calibrate sensor errors in maintaining the performance level of SDINS. In this study, an estimation technique of fixed sensor errors for SDINS calibration is discussed. First, the fixed errors of gyros and accelerometers, excluding gyro biases are estimated by the navigation information of SDINS in multi-position. The SDINS with RLG includes flexure errors. In this study, the gyros flexures are out of consideration, but the proposed procedure selects certain positions and rotations in order to minimize the influence of flexures. Secondly, the influences of random walks, flexures and orientation errors are verified via numerical simulations. Thirdly, applying the previous estimated errors to SDINS, the estimation of gyro biases is conducted via the additional control signals of close-loop self-alignment. Lastly, the experiments illustrate that the extracted calibration parameters are available for the improvement of SDINS.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.158-166
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• 1998

This paper presents a geometrical approach to the characteristic analysis of parallel mechanism with free joints intended for use as a planar task robot. Solution of the forward and inverse kinematic problems are described. Because the mechanism has only three degree-of-freedom output, constraint equations must be generated to describe the inter-relationship between actuated joints and free joints so as to describe the position and orientation of the moving platform. Once these constraints are incorporated into the kinematics model, a constrained Jacobian matrix is obtained. and it is used for the solution of the forward kinematic equations by Newton-Raphson technique. Another Jacobian matrix was derived to describe the interrelationship between actuated joints and moving platform. The stiffness, velocity transmission ratio, force transmission ratio and dexterity of the mechanism are then determined based on this another Jacobian matrix. The geometrical construction of the mechanism for the best performance was investigated using the characteristic analysis.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.446-453
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• 1999

An athlete motion during weightlifting is analyzed based on robotic manipulability, which shows dexterities by changing the position and orientation of the end-effector of robot manipulators arbitrary or along a specified direction. The athlete body is modeled as a highly redundant robot manipulator. The motion of weightlifting is analyzed based on the selected model with a power manipulability. Power manipulability and its geometric characteristics are derived by combining kinematic manipulability and dynamic manipulability. Also, manipulability-based optimal trajectory of weightlifter for given body structure of weightlifter derived through genetic algorithm.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2553-2559
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• 2012

The adsorption properties of benzene, toluene, p-xylene in MCM-41 with heterogeneous and cylindrical pore were studied using grand canonical ensemble Monte Carlo simulation. The simulated isotherms were compared with experimental ones, and the different adsorption behaviors in MCM-41 with pore diameters of 2.2 and 3.2 nm were investigated. The simulated adsorption amounts above the capillary-condensation pressure agreed with the experimental ones. The simulation results showed that most molecular planes were nearly parallel to the pore axis. This orientation was not affected by the molecular position in the pore. The molecular planes were nearly parallel to the pore surface for the adsorbate molecules close to the pore wall, and the molecules in the MCM-41 with the pore diameter of 3.2 nm were ordered along the pore axis.