• Journal of Electrical Engineering and Technology
• /
• v.11 no.4
• /
• pp.1012-1019
• /
• 2016

A robust control intended for a nonholonomic mobile robot is considered to guarantee good tracking a desired trajectory. The main drawbacks of the mobile robot model are the existence of nonholonomic constraints, uncertain system parameters and un-modeled dynamics. in order to overcome these drawbacks, we propose a robust control based on Lyapunov theory associated with sliding-mode control, this solution shows good robustness with respect to parameter variations, measurement errors, noise and guarantees position and velocity tracking. The global asymptotic stability of the overall system is proven theoretically. The simulation results largely confirm the effectiveness of the proposed control.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2006.06b
• /
• pp.67-74
• /
• 2006

In this paper, an adaptive neural network controller and its application to automatic berthing control of ship is presented. The neural network controller is trained online using adaptive interaction technique without any teaching data and off-line training phase. Firstly, the neural networks used to control rudder and propeller during automatic berthing process are presented. Finally, computer simulations of automatic ship berthing are carried out to verify the proposed controller with and without the influence of wind disturbance and measurement noise.

• Proceedings of the KIEE Conference
• /
• 2002.11a
• /
• pp.28-30
• /
• 2002

The PD in GIS leads to a charge transfer and a voltage drop across the discharge area. They cannot be measure directly but we can measure electromagnetic wave made by PD. In generally, compared with VHF band, electromagnetic waves of UHF band have a low noise therefore, we can detect the real defect with several pC in GIS using UHF method. In this paper, the U-slot microstrip patch antenna for measuring PD signal in GIS is presented. the proposed UHF sensor are designed to have large band characteristics and unaffected structure for GIS operation.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.51 no.1
• /
• pp.45-51
• /
• 2002

In this paper are presented dynamic modeling and path-tracking of differential drive wheeled-mobile robots(WMRs) having the limited drive-torques. Instantaneously coincident coordinate system, force/torque propagation and Newton's equilibrium law are used to induce the dynamic model. When drive-torques generated by inverse dynamics exceed the limitation, we make wheeled-mobile robots follow the reference path by modifying the planned reference trajectory with time-scaling method. The controller is introduced to compensate for error owing to modeling uncertainty and measurement noise. And simulation results prove that method proposed by this paper is efficient.

• 한국초전도학회:학술대회논문집
• /
• v.15
• /
• pp.11-11
• /
• 2005

• Journal of KSNVE
• /
• v.10 no.1
• /
• pp.57-63
• /
• 2000

On the basis of the concept of strain energy-weighted dissipation, an enhanced model for predicting damping in laminates is presented. In this model, the influence of transverse shear on $90^{\circ}$ laminates has been included with those of in-plane stresses on beam. Also, an experimental damping measurement is conducted with changing the length and the thickness of laminated beam specimen for confirmation of the model prediction. The theoretical predictions in $90^{\circ}$laminates were reasonably compared with experimental data. The transverse shear reveals to have an influence on the damping, behavior in $90^{\circ}$ laminates.

• Journal of Korea Society of Industrial Information Systems
• /
• v.7 no.4
• /
• pp.29-36
• /
• 2002

In this paper, a new edge detection method for area images is presented based on the scan-line image segmentation technology. The existing algorithms are lack of precision in its detections due to the noise factors such as depth perception and illumination problems when processing the 3D image into a 2D image. The general process of applying the scan-line method is to extract straight line components to determine the shape of the objects. However, we implement this method to an arc curve for precise detections. the paper proved precise detections that from off line to on line.

• Journal of Korea Multimedia Society
• /
• v.7 no.6
• /
• pp.767-780
• /
• 2004

Interaction requires dynamic relationship between objects. In ubiquitous computing environment, interaction between human and the environment is implied. Tactile interaction has so far been less addressed, while tactile sensation should be an important topic in the field of multimedia study. This paper describes development of a novel PVDF (Polyvinylidene Fluoride) dynamic tactile sensor and associated experiments. PVDF dynamic tactile sensors detect touch events applied to the sensor skin by low frequency components of the signal. Rubber skin-covered sensing material was mounted on the bones. Robust performance with low noise was figured out in our robotic experiment. Whereas most conventional sensors are interested in measurement, our dynamic tactile sensor is sensitive to change of state, which could be a key for economic understanding of happenings in the dynamic world. We note that dynamic sensing uses motion as a part of sensing modality We suggest that dynamic sensing be understood in technological terms in the perspective of interactive media and ubiquitous computing.

• Journal of Advanced Navigation Technology
• /
• v.7 no.1
• /
• pp.71-81
• /
• 2003

A new beamforming technique is presented for effectively nulling out multiple incoherent interferences incident on an equispaced linear array. The basic idea of the proposed beamformer is based on the matrix property mapping which is basically concerned with the task of recovering a signal from a noise and interference contaminated measurement made on that signal. Computer simulations are shown to illustrate the superior performance achieved with the proposed beamformer relative to that of the conventional LCMV beamformer.

• Journal of Surface Science and Engineering
• /
• v.31 no.5
• /
• pp.261-265
• /
• 1998

We investigated compositional separation of Co-23%Cr magnetic alloy thin films with varying film thicknesses. Saturation magnetization and magnetic microstructures were investigated using vibrating sample magnetometer (VSM) and scanning probe microscope (SPM), respectively. Saturation magnetization was as 700 emu/cc for films below 50 nm-thick, and changed to 430 emu/cc for the ones above 2000 nm-thick. This may be due to increment of molar volume of Cr-enriched phase as film thickness increases. The surface grain size in AFM (atomic force microscope) measurement becomes larger as film thickness increases. The MFM (magnetic force microscope) reveals that magnetic microstructure is changed from the fine spherical domains to the maze type domains as film thickness increases. We conclude that employing thickness of Co-22%Cr films below 50 nm is favorable for high density recording in order to enhance perpendicular saturation magnetization and SNR (signal to noise ratio).