• Journal of Auto-vehicle Safety Association
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• v.5 no.2
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• pp.32-38
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• 2013

This paper presents collision avoidance using model predictive control algorithm. A model predictive control algorithm determines lateral tire force and yaw moment and steering angle input and differential braking input is determined from lateral tire force and yaw moment. A constraint for model predictive control is designed for obstacle avoidance. A objective function is designed to minimize lateral tire force and yaw moment input and to follow changed lane after collision avoidance. The performance of proposed algorithm has been investigated via computer simulation conducted to vehicle dynamic software CARSIM and Matlab/Simulink.

• ETRI Journal
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• v.27 no.6
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• pp.677-684
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• 2005

A phased array antenna was fabricated using four-element ferroelectric phase shifters with a coplanar waveguide (CPW) transmission line structure based on a $Ba_{0.6}Sr_{0.4}TiO_3(BST)/MgO$ structure. Epitaxial BST films were deposited on MgO (001) substrates by pulsed laser deposition. To attain the large differential phase shift and small losses for a ferroelectric CPW phase shifter, an impedance-matching-part adding technique between the effective transmission line and connecting cable was used. The return loss and insertion loss for this techniqueadapted BST CPW device were improved with respect to those for a normal BST CPW device. For an X-band phased array antenna system consisting of ferroelectric BST CPW phase shifters, power divider, dc block, patch antenna, and programmed dc power, the steering beam could be tilted by $15^{\circ}$ in either direction.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.619-620
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• 2006

This paper presents a design of a 6-bit 2.704Gsamples/s D/A converter (DAC) for DS-CDMA UWB transceivers. The proposed DAC was designed with a current steering segmented 4+2 architecture for high frequency sampling rate. For low glitches, optimized deglitch circuit is adopted for the selection of current sources. The measured integral nonlinearity (INL) is -0.081 LSB and the measured differential nonlinearity (DNL) is -0.065 LSB. The DAC implemented in a 0.13um CMOS technology shows s spurious free dynamic range (SFDR) of 50dB from dc to Nyquist frequency. The prototype DAC consumes 28mW for a Nyquist sinusoidal output signal at a 2.704Gsamples/s. The chip has an active area of $0.76mm^2$.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.9
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• pp.850-855
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• 2006

This is concerned with the development and design of automatic maneuvering system using Differential Global Positioning System(DGPS). To achievement of autonomous maneuvering controller for giant ship, first, we investigated automatic maneuvering controller using DGPS in motor car. The sensors are configured with DGPS and digital compass. We calculated velocity and steering angle of motor car based on sensor signal. To design the controller, we derived the bicycle model and developed critically damped controller. The critically damped controller can be tracing previously appointed position in the fastest time. We are used a laptop computer to realize and the control algorithm is programmed by visual basic software. The obtained experimental results from developed system show unmanned motor car is good tracing planed positions. Hence, the system is looking forward to use the autonomous maneuvering control fur giant ship.

• Journal of the Korean Institute of Navigation
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• v.4 no.1
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• pp.51-61
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• 1980

In order to evaluate rolling characteristics of high speed container carrier the author developed yaw-sway-rudder coupled rool equation, which is likely to be 5th order differential equation. The free rolling time history with particular reference to automatic steering, was computed upon the base of the yaw-sway-rudder coupled roll equation. The computed result explained effects of $C_1$ and $C_2$ on rolling behaviors and furthermore the effect of $C_2$ proved to be very effective where $C_1$ and $C_2$ are yaw gin constant and yaw-rate gain constant of auto-pilot respectively. Computation was carried out using Matsumoto's data of hydrodynamic force derivatives of 5 meter long container model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.574-578
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• 2008

In order to achieve thrust vector control and discharge stabilization in Hall thrusters, the azimuthal nonuniformity of propellant flow rate in an acceleration channel was created. A plenum chamber was divided into two rooms by two walls and propellant flow rate supplied to each section was independently controlled. In a magnetic layer type Hall thruster, steering angle of up to ${\pm}2.3$ degree was achieved. In an anode layer type Hall thruster, discharge current oscillation amplitude was decreased with the normalized differential mass flow rate.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.157-164
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• 1995

Straight belvel gear is used mainly for steering system, final reduction and differential gear in the automobile. The more high load, high velocity driving bevel gear, the more unsafe and unpleasant. In thid study, we get a kinematic equation by modelling straight bevel gear pair with simple elastic system, the dynamic characteristic analysis about this system, we got the dynamic load factor of tooth surface. Comparing the value of dynamic load factor by calculation with the measured value of Terauchi's experimental results is similar. We think it useful to analysis the vibration and the noise of straight bevel gear in operation with the analytic method of dynamic load of straight bevel gear using in this study.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.4
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• pp.180-189
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• 2009

Currently, most automobile companies are interested in research on intelligent autonomous vehicle. They are mainly focused on driver's intelligent assistant and driver replacement. In order to develop an autonomous vehicle, lateral and longitudinal control is necessary. This paper presents a lateral and longitudinal control system for autonomous vehicle that has only mono-vision camera. For lane detection, we present a new lane detection algorithm using clothoid parabolic road model. The proposed algorithm in compared with three other methods such as virtual line method, gradient method and hough transform method, in terms of lane detection ratio. For adaptive control, we apply a vanishing point estimation to fuzzy control. In order to improve handling and stability of the vehicle, the modeling errors between steering angle and predicted vanishing point are controlled to be minimized. So, we established a fuzzy rule of membership functions of inputs (vanishing point and differential vanishing point) and output (steering angle). For simulation, we developed 1/8 size robot (equipped with mono-vision system) of the actual vehicle and tested it in the athletics track of 400 meter. Through the test, we prove that our proposed method outperforms 98 % in terms of detection rate in normal condition. Compared with virtual line method, gradient method and hough transform method, our method also has good performance in the case of clear, fog and rain weather.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.3
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• pp.51-57
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• 2010

A dual-mode direct conversion receiver is developed in $0.13\;{\mu}m$ RF CMOS process for IEEE 802.11n based wireless LAN and IEEE 802.16e based mobile WiMAX application. The RF receiver covers the frequency band between 2.3 and 2.7 GHz. Three-step gain control is realized in LNA by using current steering technique. Current bleeding technique is applied to the down-conversion mixer in order to lower the flicker noise. A frequency divide-by-2 circuit is included in the receiver for LO I/Q differential signal generation. The receiver consumes 56 mA at 1.4 V supply voltage including all LO buffers. Measured results show a power gain of 32 dB, a noise figure of 4.8 dB, a output $P_{1dB}$ of +6 dBm over the entire band.

• Journal of Biosystems Engineering
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• v.26 no.1
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• pp.29-38
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• 2001

A navigation system was developed for autonomous guidance of a combine. It consisted of a DGPS, a machine vision system, a gyro sensor and an ultrasonic sensor. For an autonomous operation of the combine, target points were determined at first. Secondly, heading angle and offset were calculated by comparing current positions obtained from the DGPS with the target points. Thirdly, the fuzzy controller decided steering angle by the fuzzy inference that took 3 inputs of heading angle, offset and distance to the bank around the rice field. Finally, the hydraulic system was actuated for the combine steering. In the case of the misbehavior of the DGPS, the machine vision system found the desired travel path. In this way, the combine traveled straight paths to the traget point and then turned to the next target point. The gyro sensor was used to check the turning angle. The autonomous combine traveled within 31.11cm deviation(RMS) on the straight paths and harvested up to 96% of the whole rice field. The field experiments proved a possibility of autonomous harvesting. Improvement of the DGPS accuracy should be studied further by compensation variations of combines attitude due to unevenness of the rice field.