• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1997.06c
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• pp.238-246
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• 1997

This study was conducted to develop a robotic transplanter for bedding plants. The robotic transplanter consisted of machine vision system, a manipulator, a gripper and plug tray transfer system. The performance of the robotic transplanter was tested and compared by two different transplanting methods, which were to consider the leaf orientation of seedlings and not to. Results of this study were as follows. (1) A cartesian coordinate manipulator for a robotic transplanter with 3 degree of freedom was constructed. The accuracy of position control was $\pm$1 mm. (2) The robotic transplanter with the machine vision system, the manipulator, the gripper and the transfer system was developed and tested with a shovel-type finger. Without considering the orientation of leaves, the success rates of transplanting healthy cucumber seedlings in 72-cell and 128-cell plug-trays were 95.5% and 94.5% respectively. Considering the orientation of leaves, the success rates of transplanting healthy cucumber seedling in 72-cell and 128-cell plug-trays were 96.0% and 95.0% respectively.

• Korean Journal of Optics and Photonics
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• v.27 no.5
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• pp.165-173
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• 2016

In this paper, we propose a three-dimensional (3D) scanning system based on two line lasers. This system uses two line lasers with different wavelengths as light sources. 532-nm and 630-nm line lasers can compensate for missing scan data generated by geometrical occlusion. It also can classify two laser planes by using the red and green channels. For automatic registration of scanning data, we control a stepping motor and divide the motor's rotational degree of freedom into micro-steps. To this end, we design a control printed circuit board for the laser and stepping motor, and use an image processing board. To compute a 3D point cloud, we obtain 200 and 400 images with laser lines and segment lines on the images at different degrees of rotation. The segmented lines are thinned for one-to-one matching of an image pixel with a 3D point.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2252-2257
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• 2003

In this paper, we develop the so-called functional test model for magnetic bearing reaction wheels. The functional test model has three degree of freedom, which consists of one axial suspension from gravity and the other two axes gimbaling capability to small angle, and does not include the motor. For the control of the functional test model, we derive the optimal electromagnetic forces based on the least squares method, and use the proportional-integral-derivative controller. Then, we develop a hardware setup, which mainly consists of the digital signal processor and the 12-bit analog-to-digital and digital-to-analog converters, and show the experimental results.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.56-64
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• 2013

Crabbing motion is the pure sway motion of a ship without surge velocity. Thus, it can be applied to a berthing operation. Crabbing motion is induced by a peculiar operation method called the push-pull mode. The push-pull mode is induced by using a combination of the main propeller and side thruster. Two propellers generating the same amounts of thrust and rotating in opposite directions produce some yawing moment on a vessel but do not induce longitudinal motion. With the additional operation of side thrusters, the push-pull mode is used to induce a large amount of lateral force. In this paper, three-degree-of-freedom equations of motion such as for the surge, sway, and yaw are constructed for the crabbing motion. Based on these equations of motion, a feedback linearization control method is applied to auto-berthing control for a twin-screw ship with side thrusters. The controller can deal with the nonlinearity of a system, which is present in the berthing maneuver of a twin screw ship. A simulation of the auto-berthing of a ship is performed to validate the performance of the designed controller.

• Advances in Automotive Engineering
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• v.1 no.1
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• pp.123-141
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• 2018

Hardware-in-the-loop (HiL) simulation is a very powerful tool to design, test and verify automotive control systems. However, well-validated and high degree of freedom vehicle models have to be utilized in these simulations in order to obtain realistic results. In this paper, a vehicle dynamics model developed in the Carsim Real Time program environment and its validation has been performed using experimental results. The developed Carsim real time model has been employed in the Tofas R&D hardware-in-the-loop simulator. Experimental and hardware-in-the-loop simulation results have been compared for the standard FMVSS No. 126 test and the results have been found to be in good agreement with each other. Two electronic stability control (ESC) algorithms, named the Basic ESC and the Integrated ESC, taken from the earlier work of the authors have been tested and evaluated in the hardware-in-the-loop simulator. Different evaluation methods have been formulated and used to compare these ESC algorithms. As a result, the Integrated ESC system has been shown superior performance as compared to the Basic ESC algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.585-589
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• 2016

Recently, the robotic assist system for cardiovascular intervention gets continuously growing interest. The robotic cardiovascular intervention systems are largely two folds, systems for cardiac ablation procedure assist and systems for vascular intervention assist. For the systems, the clinician controls the catheter inserted through blood vessel to the heart via a master console or master manipulator. Most of the current master manipulators have structure of joystick-like pivoting 2 degree of freedom (DOF) handle in the core, which is used in parallel with other sliding switches and input devices. It however is desirable to have customized and optimized design manipulator that can provide clinician with intuitive control of the catheter motion fully utilizing the advantage of the use of robotic structure. A 6 DOF kinematic mechanism that can capture the motion control intention of the clinician in translational 3 DOF and rotational 3 DOF is proposed in this paper. Also, a master-slave motion relationship specially designed for the cardiac catheter manipulation motion is proposed and implemented in an experimental prototype. Design revision for implementation of more efficient motion and experiment in combination with an experimental slave robot system for catheter manipulation are underway.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.347-357
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• 2017

The applications of active control is being more popular nowadays. Several control algorithms have been developed to determine optimum control force. In this paper, a Chaotic Particle Swarm Optimization (CPSO) technique, based on Logistic map, is used to compute the optimum control force of active tendon system. A chaotic exploration is used to search the solution space for optimum control force. The response control of Multi-Degree of Freedom (MDOF) shear buildings, equipped with active tendons, is introduced as an optimization problem, based on Instantaneous Optimal Active Control algorithm. Three MDOFs are simulated in this paper. Two examples out of three, which have been previously controlled using Lattice type Probabilistic Neural Network (LPNN) and Block Pulse Functions (BPFs), are taken from prior works in order to compare the efficiency of the current method. In the present study, a maximum allowable value of control force is added to the original problem. Later, a twenty-story shear building, as the third and more realistic example, is considered and controlled. Besides, the required Central Processing Unit (CPU) time of CPSO control algorithm is investigated. Although the CPU time of LPNN and BPFs methods of prior works is not available, the results show that a full state measurement is necessary, especially when there are more than three control devices. The results show that CPSO algorithm has a good performance, especially in the presence of the cut-off limit of tendon force; therefore, can widely be used in the field of optimum active control of actual buildings.

• Journal of Navigation and Port Research
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• v.35 no.3
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• pp.227-233
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• 2011

This paper presents the tracking and stabilization problem of a night vision system for marine surveillance. Both a hardware system and software modules are developed to control azimuth and elevation axes independently with compensation for ship motion. A two degree of freedom(2DOF) PID controller is designed and its parameters are tuned using a real-coded genetic algorithm(RCGA). Simulation demonstrates the effectiveness of the proposed method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.359-365
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• 2011

A mobile surveillance robot is defined as a surveillance robot system that is mounted on a mobile platform and is used to protect public areas such as airports or harbors from invaders. The mobile surveillance robot that is mounted on a mobile platform consists of a gun module, a camera system module, an embedded control system, and AHRS (Attitude and Heading Reference System). It has two axis control systems for controlling its elevation and azimuth. In order to obtain stable images for targeting invaders, this system requires a stabilizer to compensate any disturbance due to vehicle motion. In this study, a virtual model of a mobile surveillance robot has been created and ADAMS/Matlab simulations have been performed to verify the suitability of the proposed stabilization algorithm. Further, the suitability of the stabilization algorithm has also been verified using a mock-up of the mobile surveillance robot and a 6-DOF (Degree Of Freedom) motion simulator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1111-1116
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• 2001

A transient T-F(time-frequency) signal processing technique is applied to a tilt drop and a linear shock test rigs for identification of shock characteristics of hard disk drive (HDD). The T-F technique essentially tracks the shock characteristics of pivot point response as well as head slap and lift-off phenomena. From the T-F analysis result, the shock characteristic in HDD is modeled by the two degree of freedom coupled-dynamic system, which consists of actuator arm and suspension. As shock designing tool, the maximax shock response spectrum is employed for prediction of shock performance. Finally, the shock control technique is tested with newly designed actuator arm and suspension. Experimental head slap test result shows that the shock performance is much higher with the new shockproof designed model than the current model