• Journal of IKEEE
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• v.19 no.2
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• pp.225-231
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• 2015

The parameter K which decides how much to convert wind energy to electric energy in MPPT(maximum power point tracking) control of wind turbine system using torque controller is changed because blade shape and air density change. If the parameter K is not optimal value, power lose occur. The changed parameter K is important issue in wind turbine system. In this paper, to solve this problem, considering wind turbine system using back-to-back converter control and torque control, we propose the adaptive MPPT algorithm which performs fast control by using initial K, estimates mechanical power using Kalman filter method, uses the estimated mechanical power as input for MPPT algorithm again, and consequently performs optimal MPPT control.

• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.234-238
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• 2012

Propofol is an anesthetic commonly used to provide sedation or to induce and maintain an anesthetic stated. However, there are reports which indicate propofol may cause psychological dependence or be abused. In the present study, we used various behavioral tests including climbing test, jumping test, conditioned place preference, and self-administration test to assess the dependence potential and abuse liability of propofol compared to a positive control (methamphetamine) or a negative control (saline or intralipid). Among the tests, the conditioned place preference test was conducted with a biased method, and the selfadministration test was performed under a fixed ratio (FR) 1 schedule, 1 h per session. No difference was found in the climbing test and jumping test, but propofol (30 mg/kg, i.p.) increased the rewarding effect in the conditioned place preference test, and it showed a positive reinforcing effect compared to the vehicle. These results indicate that propofol tends to show psychological dependence rather than physical dependence, and it seems not to be related with dopaminergic system.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.6 no.2
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• pp.15-22
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• 2012

The mechanical system of wearable walking assist robot needs to be optimized for adapting with human body structure and the planned control algorithm should have a secure procedure when a incongruity situation which can cause musculoskeletal injury occurs because a wearable robot is attached to a body. The understanding of walking or musculoskeletal motions characteristics must be preceeded and analyzed for developing novel wearable walking assist robot. In this study we tried to find out the capacities of powers and torques of joint actuators to design optimized performances of system and to obtain the analysis data to figure out the characteristics of joint movements during some types of walk. The major types of walk and motion are stair climbing and descending, sit-to-stand motion, and slope walking. In this study all these motions were analyzed experimentally except slope walking.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.617-621
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• 2001

This paper presents a maximum power point tracking algorithm for Photovoltaic array using only instantaneous output current information. The conventional Hill climbing method of peak power tracking has a disadvantage of oscillations about the maximum power point. To overcome this problem, we have developed a algorithm, that will estimate the duty ratio corresponding to maximum power operation of solar cell. The estimation of the optimal duty ratio involves, finding the duty ratio at which integral value of output current is maximum. For the estimation, we have used the well know Lagrange's interpolation method. This method can track maximum power point quickly even for changing solar insolations and avoids oscillations after reaching the maximum power point.

• Journal of Power Electronics
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• v.2 no.3
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• pp.155-161
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• 2002

This paper presents a maximum power point tracking algorithm for Photovoltaic array using only instantaneous output current information. The conventional Hill climbing method of peak power tracking has a disadvantage of oscillations about the maximum power point. To overcome this problem, we have developed an algorithm that will estimate the duty ratio corresponding to maximum power operation of solar cell. The estimation of the optimal duty ratio involves, finding the duty ratio at which integral value of output current is maximum. For the estimation, we have used the well know Lagrange's interpolation method. This method can track maximum power point quickly even for changing solar isolation and avoids oscillations after reaching the maximum power point.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1019-1022
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• 2002

Pipe-cutting machines have been used in many fields. Recently, an automatic pipe-cutting machine that uses magnet has born developed. In this paper, a magnetic-type automatic pipe-cutting machine that attaches itself and performs unmanned cutting process is proposed. It is designed that there is a room at the bottom of its body to contain a magnet. And it uses magnetic force between the magnet and the pipe surface to prevent slip and to attach the machine to the pipe against gravity. Also the magnetic force is adjustable by changing the gap between the magnet and the pipe. This machine is, however, necessary to control cutting velocity for the elevation of work efficiency and the adjustable faculties. During pipe cutting process, the gravity acting on the pipe-cutting machine widely varies. That is, the cutting machine gets fast when moving from the top to the bottom of the pipe and slow when moving from the bottom to the top. Actually the system is kind of a non-linear system where the gravity is function of climbing angle of the cutting machine along the pipe. Especially jerking motion is critical. Therefore, authors design the non-linear controller that estimates the current position of the machine along the pipe and compensates the effect of gravity in this paper. It receives the feed back signal from the encoder.

• Journal of Biosystems Engineering
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• v.37 no.5
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• pp.287-295
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• 2012

Purpose: Some of the most representative approaches are to apply next generation technologies to save energy consumption, fully automated control system to appropriately maintain environmental conditions, and autonomous assistance system to reduce labor load and ensure operator's safety. Nevertheless, improvement of upcoming method for soil cultured greenhouse has not been sufficiently achieved. Geometrical complexity of ground in protected crop cultivation might be one of the most dominant factors in design of autonomous vehicle. While there is a practical solution fairly enough to promise an accurate travelling, such as autonomous sprayer guided by rail or induction coil, for various reasons including the limitation of producer's budget, the previously developed sprayer has not been widely distributed to market. Methods: In this study, we developed an autonomous sprayer considering travelling performance on geometrical complexity of ground in soil cultured greenhouse. To maintain a stable travelling and to acquire a real time feedback, common wire with 80 mm thick and body frame and sprayer boom. To evaluate performance of the prototype, tracking performance, climbing performance and spraying boom's uniform leveling performance were individually evaluated by corresponding experimental tests. Results: The autonomous guidance system was proved to be sufficiently suitable for accurate linear traveling with RMS as lower than approximately 10 cm from designated path. Also the prototype could climb $10^{\circ}$ of ground's slope angle with 40 kg of water weight. Uniform leveling of spraying boom was successfully performed within $0.5^{\circ}$ of sprayer boom's slope. Conclusions: Considering more complex pathways and coarse ground conditions, evaluations and improvements of the prototype should be performed for promising reliability to commercialization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6034-6039
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• 2012

In this paper, this may appear to exacerbate it met slopes of the mobile robot moves to overcome this by driving can occur if the mobile robot system has its own sleep problems driving progress in until you hit the target and solvedriving straight driving safer model for adaptive fuzzy control method of mobile robot based control algorithm is proposed. First, we propose a model based adaptive fuzzy controller, if possible, the dynamics model of the mobile robot, including model-based controller is designed to determine if you can check the condition of the mobile robot climbing and driving the mobile robot to overcome the slope and the to overcome driving control. Enough considering the ground friction forces and ensure the stability of the mobile robot system and the disturbance compensation, etc. In this case, the controller design will be possible. In addition, the nonlinear model, the dynamic characteristics of the mobile robot control method of adaptive fuzzy control techniques in the design that you want to fully reflect Non-holonomic system of mobile robots and solve sleep problems, and will be useful enough, it was verified through computer simulations.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.4
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• pp.374-379
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• 2014

Mobile robots with omni-directional wheels can generate instant omni-directional motion without requiring extra space to change the direction of the body. Therefore, they are capable of moving in an arbitrary direction under any orientation even in narrow aisles or tight areas. In this research, an omni-directional mobile robot based on Mecanum wheels was developed to achieve omni-directionality. A CompactRIO embedded real-time controller and C series motion and I/O modules were employed in the control system design. Ultrasonic sensors installed on the front and lateral sides were utilized to measure the distance between the mobile robot and the side wall of a workspace. Through intensive experiments, a performance evaluation of the mobile robot was conducted to confirm its feasibility for industrial purposes. Mobility, omni-directionality, climbing capacity, and tracking performance of a squared trajectory were selected as performance indices to assess the omni-directional mobile robot.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.319-325
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• 2004

The major factors that make ZEV affordable are the range and cost. The development of advanced batteries such as Ni-MH battery can solve the problem partly； on the hand the battery management system is an efficient way. Ni-MH battery and battery ECU is a key component influencing ZEV performance, such as range, acceleration and hill-climbing capability. Because most problems related to battery such as short circuit, over-discharge and overcharge occur easily during operation, it is necessary to develop a dedicated battery ECU for HEV. This paper proposes a new SOC algorithm for the HEV based on the terminal voltage and current integration. And battery ECU was designed and analyzed. Also, the validity is confirmed through experiment.