• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1229-1231
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• 2002

This paper presents the design of DC protection system of Light Rail Transit system. Especially, the composition and interface for DC Switchgear. Digital protection unit and sort of protection algorithm are focused. DC Switchgear (DCSWGR) for LRT testline consist of 5 different panels with peculiar characteristics are examined. Also Basic actuation principle for DC fault select relay (50F), Line Test Device (LTD), DC Overcurrent(OCR) relay are introduced.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.12
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• pp.1041-1047
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• 2002

It is known that parallel-type mechanisms have many singularities than serial-type mechanisms. In haptic application, these singularities deteriorate the system performance when the haptic system displays the reflecting force. Moreover, different from general manipulators, haptic systems can't avoid the singular point because they are operated by user's random motion command. Although many singularity-free algorithms for serial mechanisms have been proposed and studied. singularity-free algorithms for parallel haptic application have not been deeply discussed. In this paper, various singularity-free algorithms, which are appropriate to parallel haptic system, will be discussedand evaluated.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1131-1135
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• 2004

In the virtual environment, force feedback to the human operator makes virtual experiences more realistic. However, the force feedback using active actuators such as motors can make the system active and sometimes unstable. To ensure the safe operation and enhance the haptic feeling, stability should be guaranteed. Both motors and brakes are commonly used for haptic device. A brake can generate a torque only against its rotation, but it is intrinsically stable. Consequently, motors and brakes are complementing each other. In this research, a two degree-of-freedom (DOF) haptic device equipped with both motors and brakes has been developed to provide better haptic effects. Each DOF is actuated by a pair of motor and brake. Modeling of the environment and the control method are needed to utilize both actuators. For various haptic effects, contact with the virtual wall and representation of friction effect are extensively investigated in this paper. It is shown that the hybrid haptic system is more suited to some applications than the motor-based active haptic system.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1243-1246
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• 2003

It is known that structure of Human's brain information system is controlled by cerebral cortex mainly. Cerebral cortex is divided by sensory area, motor area and associated area largely. Sensory area takes part in information from environment and motor area is actuation by decision as associated area determined. It is possible to copy brain information system by input-output pattern. but there is difficulty in modeling of memorizing new information. Such action is performed by Limbic Lobe and Papez circuit which is controlled by intrinsic emotion. So we need of definition of emotion's role in decision. In this paper, we define roles of emotion in intrinsic decision using Dynamic Cognitive Maps(DCMs). The emotion is evaluated by outside information then intrinsic decision performed as how much emotion variated. The dynamic cognitive maps take part in emotion evaluating process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.446-450
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• 2002

Pneumatic system has been mainly used as main equipment for actuation and control of compressed air force in manufacturing industry, pneumatic circuit for the most part is used in Meter-Out circuit. Meter-Out circuit method is Flow Control Valve to fit in exhaust part of cylinder port. In the reverse, Meter-In circuit is Flow Control Valve to fit in input part of cylinder port. This study examines the dynamic characteristics comparison of Meter-In and Meter-Out Circuits in the pneumatic circuits. The results of the experimental research are obtained to the followings: i ) System Response is Meter-In Circuit more than Meter-Out one before cushion zone. ii) we conjectured that the collision of piston and head cover is ease to collide Meter-In Circuit more than Meter-Out one at the stroke end part.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.85-92
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• 2002

This paper presents the effects of design and operating parameters to meet the static and dynamic performances of the electro-mechanical valve(EMV) actuator which can provide more flexible controllability of valve events compared to conventional variable valve actuation devices. The model of the EMV system was also set up and applied to identify the dynamic behavior of the system. And the effects of external disturbances were also investigated such as cylinder pressure, armature neutral position and current supplying time effects and so on. Experiments were carried out to verify the model using the prototype actuator on test bench, it was found that there is a relatively good agreement between experimental data and modeling results. Also, the actuators meet the general engine speed range (over 6000rpm) and the variable valve event control for various VVT effects.

• Nuclear Engineering and Technology
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• v.29 no.2
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• pp.167-174
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• 1997

The method that the operating condition of Control Rod Drive Mechanism (CRDM) can be monitored without mounting sensors within CRDM housing was developed, and by using this developed method the closed-loop controller for the CRDM was designed which can optimize the performance and maximize the reliability of CRDM operation. Neural network is utilized as pattern recognition engine in detecting CRDM actuation. In this paper, most problems in previous open loop system are resolved. The control algorithms for closed-loop system ore developed and implemented within the hardware of timing controller based on microprocessor. All functions in the timing controller ore verified by means of real time CRDM simulator. The results show that the timing controller performs its intended functions properly.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.4
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• pp.767-779
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• 2017

Automated mission planning for unmanned aerial vehicles (UAVs) is difficult because of the propagation of several sources of error into the solution, as for any large scale autonomous system. To ensure reliable system performance, we quantify all sources of error and their propagation through a mission planner for operation of UAVs in an obstacle rich environment we developed in prior work. In this sequel to that work, we show that the mission planner developed before can be made robust to errors arising from the mapping, sensing, actuation, and environmental disturbances through creating systematic buffers around obstacles using the calculations of uncertainty propagation. This robustness makes the mission planner truly autonomous and scalable to many UAVs without human intervention. We illustrate with simulation results for trajectory generation of multiple UAVs in a surveillance problem in an urban environment while optimizing for either maximal flight time or minimal fuel consumption. Our solution methods are suitable for any well-mapped region, and the final collision free paths are obtained through offline sub-optimal solution of an mTSP (multiple traveling salesman problem).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.813-816
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• 2011

The actuation and leakage tests of solenoid valve for propellant tank pressurization system have been conducted. The response time of solenoid valve manufactured is satisfactory to perform requirement. However, leakage was found at the upper part seat of relief valve inside solenoid valve. Solenoid valve was disassembled in order to discover leakage causes. We found out that the upper seat of relief valve was damaged. Through this study, the development possibility of propellant tank pressurization solenoid valve was confirmed.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.832-837
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• 1991

After many years of proliferation, the nuclear industry is indebted for a formidable consequence, the safe management of spent fuel. Naturally, the high radioactivity involved with such process motivates the development of effective telerobotic systems. Nevertheless, the existing master-slave type of tele manipulators are limited in effectiveness by the human operator's limited sensory and manipulation capabilities. This paper presents the result of a research effort to resolve such problems by assigning the slave manipulator a certain degree of intelligence; sensing and actuation. In the presented system, a perception-action loop is achieved using ultrasonic range sensor and laser distance sensor interfaced with the PUMA 760 industrial robot system, and applied to automating impact wrenching task for unbolting the lid of nuclear spent fuel cask. The perception-action loop performs determination of the cask location, collision avoidance and centering of the impact wrench onto the bolt head. To aid the insertion task and to provide versatility a mounting module consisting of an RCC device and an automatic tool changer is designed and implemented. The performance of the developed system is tested on the model cask and the result is given.