• Journal of Korea Spatial Information System Society
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• v.9 no.3
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• pp.81-89
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• 2007

We analyzed the technology portfolio matrix for the car navigation technology using QFD method and accordingly suggested the navigation technology development direction. QFD is a useful tool to analyze the customer demands and the technologies. Depending on the survey results from the latent customers and the technology capabilities from the study of the national institutions, we suggested technology portfolio matrix. The visual HMI technology, safe driving support technology, and the navigator information management technology are the most prospective area for R&D investment according to the portfolio matrix.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.1025-1030
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• 2001

As the pre-stage of making 3D stabilizing systems, at this paper designed 2D stabilizing system. This is composed of two axes stabilizing platform to preserve targeted direction while vehicle is moving. The system maintains stabilization by recovering error using the rate gyro with DSP TMS320F240 as controller, vibratory rate gyro (Tokimec co. TFG -l60D) as gyro scope, SD1015B52-1·SD1004C04-l/DM1015B DM1004C as direct drive driver/motor, PI control as control algorithm. This paper got a comparably good stabilization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.633-637
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• 2001

In this paper, we proposed model creation algorithm for multiple moving objects tracking. The proposed algorithm is divided that the initial model creation step as moving objects are entered into background image and the model reformation step in the moving objects tracking step. In the initial model creation step, the initial model is created by AND operating division image, divided using difference image and clustering method, and edge image of the current image. In the model reformation step, a new model was reformed in the every frame to adapt appearance change of moving objects using Hausdorff Distance and 2D-Logarithmic searching algorithm. We simulated for driving cart in the road. In the result, model was created over 98% in case of irregular approach direction of cars and tracking objects number.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.919-922
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• 2013

Currently, society thinks human-health is very important. As a result, the number of individual bikes is increasing. And bicycle accident rate is increasing every year. We have developed the safety-equipment utilizing a smartphone. Because, in order to reduce the rate of bicycle accidents. The working principle is that the connection between the bicycle and safety equipment with built-in Bluetooth chip. Information of bike-driving Is measured using a smartphone with built-in gyro sensor. I made an algorithm for specifying a direction by using the values of the gyro sensor. With this algorithm, it is possible to reduce the accident rate of the bicycle.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.151-159
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• 1999

A self-propulsive polishing robot is proposed as a method which automates a floor polisher. The proposed robot with two rotary brushes does not require any mechanism such as wheels to obtain driving forces. When the robot polishes a floor with its two brushes rotating, friction forces occur between the two brushes and the floor. These friction forces are used to move the robot. Thus, the robot can move in any direction by controlling the two rotary brushes properly. In this paper, firstly a dynamics model of a brush is presented. It computes the friction force between the brush and the floor. Secondly, the dynamics of the proposed robot is presented by using the bush dynamics. Finally, the inverse dynamics is solved for the basic motions, such as the forward, backward, leftward, rightward motions and the pure rotaion. This paper will contribute to realize a self-propulsive polishing robot as proposed above, In addition, this paper will give basic ideas to automate the concrete floor finishing trowel, because its basic idea for motion is similar to that of the proposed robot.

• International Journal of Automotive Technology
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• v.3 no.2
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• pp.71-78
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• 2002

A new control method far vision-based autonomous vehicle is proposed to determine navigation direction by analyzing lane information from a camera and to navigate a vehicle. In this paper, characteristic featured data points are extracted from lane images using a lane recognition algorithm. Then the vehicle is controlled using new Levenberg-Marquardt neural network algorithm. To verify the usefulness of the algorithm, another algorithm, which utilizes the geometric relation of a camera and vehicle, is introduced. The second one involves transformation from an image coordinate to a vehicle coordinate, then steering is determined from Ackermann angle. The steering scheme using Ackermann angle is heavily depends on the correct geometric data of a vehicle and a camera. Meanwhile, the proposed neural network algorithm does not need geometric relations and it depends on the driving style of human driver. The proposed method is superior than other referenced neural network algorithms such as conjugate gradient method or gradient decent one in autonomous lateral control .

• Journal of Biosystems Engineering
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• v.19 no.3
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• pp.163-174
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• 1994

This study was conducted to investigate the dynamic motion of knife drive system of combine harvester. A computer program was developed to simulate the dynamic motion of the knife drive linkage and its algorithm was evaluated through experiments. The results are summarized as follows : 1. The theorectical horizontal (the direction of knife's reciprocating motion) reaction forces at the supporting point of rocker arm and crank arm were changed in the similar sinusoidal trends with the measured reaction forces. 2. The maximum values of shaking moment and reaction force per one revolution of crank arm followed polynomial trends as the rotational speed of crank shaft increased. The unbalanced force acting on the driving system increased at high speed. Therefore, the rotational speed of crank shaft should be maintained in proper range at increased forward speed to decrease vibration of the knife drive system. 3. The added mass to the crank arm increased the dynamic unbalanced force at the supporting point of rocker arm. It counterbalanced the reaction force at the supporting point of crank arm.

• Ceramist
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• v.22 no.1
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• pp.56-69
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• 2019

Recent advances in low-power sensors and transmitters are driving the search for standalone power sources that utilize unused ambient energy. These energy harvesters can alleviate the issues related to the installation and maintenance of sensors. Particularly piezoelectric energy harvesters, with the ability to convert ambient mechanical energy into useful electricity, have received significant attention due to their high energy density, low cost and operational stability over wide temperature and pressure conditions. In order to maximize the generated electrical power, the natural frequency of the piezoelectric energy harvester should be matched with the dominant frequency of ambient vibrations. However, piezoelectric energy harvesters typically exhibit a narrow bandwidth, thus, it becomes difficult to operate near resonance under broadband ambient vibration conditions. Therefore, the resonating of energy harvesters is critical to generate maximum output power under ambient vibration conditions. For this, energy harvesters should have broadband natural frequency or actively tunable natural frequency with ambient vibrations. Here, we review the most plausible broadband energy harvesting techniques of the multi-resonance, nonlinearity, and self-resonance tuning. The operation mechanisms and recent representative studies of each technique are introduced and the advantages and disadvantages of each method are discussed. In addition, we look into the future research direction for the broadband energy harvester.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.123-125
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• 2001

Salient pole rotor type single phase SRM(switched reluctance motor) uses the magnetic fluxes of radial and axial direction at the same time. Therefore the output power per unit volumn is very high and shaft length can be shorter than any other types of SRM with same output. Also, It can be manufactured with low cost thanks to simple structure and driving circuit. We already designed and manufactured prototype using the dynamic output equation of general rotating machine but the effect by salient pole structure was not considered. The most optimal design parameters for salient pole rotor type single phase SRM will be selected by comparing and analyzing the results from 3D FEM analysis, experimental values of the torque versus speed characteristics. and the nux linkage of prototype. Results for the former 3D FEM analysis and torque vs. speed characteristics were already obtained. Finally, we will measure the nux linkage of salient pole rotor type single phase SRM.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.4
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• pp.361-372
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• 2010

Optical image stabilization is a technique to compensate the image blurring caused by some vibrations of camera at the exposure time. Pitching and yawing of camera are sensitive to the image quality so they are usually compensated by optical image stabilization. Corresponding pitching and yawing of a camera, a lens or the image sensor is translated in two-axis direction and then the optical path of camera is adjusted. In this paper, two-axis OIS actuator for mobile camera module is suggested and designed. The actuator is a voice-coil actuator that uses the electromagnetic force of voice-coil to make compensation motions. And ball bearing is used to reduce friction force. Magnetic attractive force between magnets and yokes acts as a preload and magnet springs. Prototype actuator is fabricated to measure the friction force and to verify the feasibility of the OIS actuator with ball bearing. At last, the actuator is improved in consideration of driving force and friction force. Design of experiments is used for designing the actuator.