• The Journal of Korea Robotics Society
• /
• v.7 no.1
• /
• pp.45-56
• /
• 2012

This paper proposes how to improve the performance of CSS-based indoor localization system. CSS based localization utilizes signal flight time between anchors and tag to estimate distance. From the distances, the 3-dimensional position is calculated through trilateration. However the error in distance caused from multi-path effect transfers to the position error especially in indoor environment. This paper handles a problem of reducing error in raw distance information. And, we propose the new localization method by pattern matching instead of the conventional localization method based on trilateration that is affected heavily on multi-path error. The pattern matching method estimates the position by using the fact that the measured data of near positions possesses a high similarity. In order to gain better performance of localization, we use EKF(Extended Kalman Filter) to fuse the result of CSS based localization and robot model.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.3
• /
• pp.177-183
• /
• 2004

The out-of-positioned small female drivers are most likely to be injured during airbag deployment due to their stature and proximity to the steering wheel and airbag module. In order to investigate the injury mechanisms, some experimental studies with Hybrid III 5% female dummy and with female cadavers could be found from the open literatures. However, the given information from those experimental studies is quite limited to the standard conditions and might not be enough to estimate the airbag inflation aggressiveness regarding on the occupant responses and injury. In this study, a finite element analysis has been performed in order to investigate the airbag-induced injuries. A finite element 5% female human model in anatomical details has been developed. The validation results of the model are also introduced in this paper.

• Journal of Biomedical Engineering Research
• /
• v.28 no.3
• /
• pp.363-368
• /
• 2007

Most surgery illumination systems have been developed as passive systems. However, sometimes it is inconvenient to relocate the position of the illumination system whenever the surgeon changes his pose. To cope with such a problem, this study develops an auto-illumination system that is autonomously tracking the surgeon's movement. A 5-DOF serial type manipulator system that can control (X, Y, Z, Yaw, Pitch) position and secure enough workspace is developed. Using 3 ultrasonic sensors, the surgeon's position and orientation could be located. The measured data aresent to the main control system so that the robot can be auto-tracking the target. Finally, performance of the developed auto-illuminating system was verified through a preliminary experiment in the operating room environment.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.560-562
• /
• 2006

In this paper, Correct problem in dead reckoning system and proposed about position error revision techniques of mobile robot to use RFID tag for position awareness. With the dead reckoning system, as the accumulation of error are unavoidable because of accumulation of informations as the time passage, so it is impossible to get correct information about posture, including torrent direction, movement distance, etc. As one of compensation method, the suggested method is that after selecting special area (corridor), compensate absolute location information by arranging two line of RFID tag along two side of corridor. Through this suggested method, it could be used when robot wants to move in limited areas.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.461-465
• /
• 1996

Position and rate control modes arc the two common modes for controlling remote manipulators with joysticks or hand controllers. Generally, position mode is easier for teleoperation than rate modes, when the manipulation work space is small or comparable to the human operator's control space. When the telemanipulator's work space is very large, human operator's control motion range must be large to allow telemanipulator's full range of motion resulting poor control resolution. One way to solve the poor resolution problem is to use indexing. However, rate mode can provide any higher degree of resolution without use of indexing. If two modes are mixed, master controller will be more convenient. The mixed mode algorithm, changes operating mode from position mode to rate mode or vise versa using fuzzy logic. The fuzzy logic algorithm, which has been designed to recognize the teleoperator's intended motion properly, provides an intelligence to a master controller.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.6
• /
• pp.323-332
• /
• 2003

This paper proposes a variable structure position controller for an induction motor(IM) which uses a reaching law and an integral compensating nonlinear switching function. With the integral compensating nonlinear switching function, both very low overshoot and high steady state control accuracy can be obtained by compensating the states chattering problem due to the unmodelled dynamics of inverter and feedback sensors. With the reaching law, reaching mode can be established quantitatively during transient state so that dynamic control performance is improved. For experiment a digital servo driver which consists of a DSP and an IPM inverter was developed. With the various experimental results, IM position control performance was verified.

• Journal of Yeungnam Medical Science
• /
• v.25 no.2
• /
• pp.150-153
• /
• 2008

A 67-year-old woman with severe congestive heart failure (New York Heart Association, NYHA class IV) was set to receive general anesthesia for cardiac surgery. For several months, she had been in a constant sitting position from which the slightest change evoked dyspnea. A patient in such a condition is rarely considered a candidate for general anesthesia, because such patients are never eligible for any type of surgery other than that used to fix the heart problem itself. We report this case to explain how anesthesia was induced with the patient sitting in a crouching position and discuss other methods of induction that can probably be used in similar situations.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.607-612
• /
• 1992

This paper presents a tip position control of a single-link flexible arm with a payload by using closed loop control. The shifting problem of the arm from the initial position to desired position is considered by the variation of the displacement gain $G_{p}$ and velocity gain $G_{v}$. The system is composed of a flexible arm with payload, DC servomotor, and a ballscrew mechanism. The flexible arm is mounted on a mobile stage driven by a servomotor and ballscrew. As a result, the increase of the displacement and velocity gain respectively comes to the reduction of tip vibration. Theoretical results are approximately in good agreement with those obtained experimentally.y.y.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1992.04a
• /
• pp.185-189
• /
• 1992

This paper prsents an end-point control of a one-link flexible arm with a payload by using closed loop control. Tip position of arm is shifted by the base motion according to DC servomotor, whivh is driven by a feedback signal composed of the tip displacement and the estimated tip velocity. The shifting problem of the arm from initial position to desired position is considered by the variation of the displacement gain Gd and velocity agin Gv. Theoretical results are obtained by applying the method of the Laplace transform to the governing equations and the method of numerical inversion. This system is composed of a flexible arm with payload, DC servomotor, and a ballscrew mechanism. The flexible arm is mounted on a mobile stage driven by a servomotor and ballscrew. In controlling the tip displacement of flexible arm, the fundamental bode vibration is supressed more rapidly with an increase of the velocity feedback gain Gv and the feedback displacemenmt gain Gd. Theretical responses are approximately in good agreement with those obtained experimentally.

• Journal of Construction Engineering and Project Management
• /
• v.5 no.4
• /
• pp.7-11
• /
• 2015

The luffing-tower crane (T/C) is a key facility used in the vertical and horizontal transportation of materials in a tall building construction. Locating the crane in an optimal position is an essential task in the initial stages of construction planning. This paper proposes a new optimization model to locate the luffing T/C in the optimal position to minimize the transportation time. A newly developed mathematical formula is suggested to calculate the transportation time of luffing T/C correctly. An optimization algorithm, the Harmony Search (HS) algorithm, was used and the results show that HS has high performance characteristics to solve the optimization problem in a short period of time. In a case study, the proposed model offered a better position for T/C than the previous heuristic approach.