• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.199-201
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• 2002

Cancer therapy using high-energy $^{12}$ C ions is successfully under way at HIMAC, Japan. An alternative beam to $^{12}$ C is $^{11}$ C ions. The merit of $^{11}$ C over $^{12}$ C is its capability for monitoring spatial distribution of the irradiated $^{11}$ C by observing the $\beta$$^{+}$ decay with a good position resolution. One of the several problems to be solved before its use for therapy is the amount of nuclear interaction that deteriorates the dose concentration owing to the Bragg curve. Utilizing the dedicated secondary beam course for R&D studies at HIMAC, we measured the total energy loss of $^{11}$ C ions in a scintillator block that simulates the soft tissue in human bodies. In addition to the total absorption $^{11}$ C peak, non-negligible bump-shaped contribution is observed in the energy spectrum. The origin of the bump contribution can be nuclear interaction of the incident $^{11}$ C ions with hydrogen and carbon atoms. Further studies to reduce the ambiguity in dose distribution are mentioned.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.157-178
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• 2001

In this paper, the nonlinear control of high precision pointing stabilization system using feedback-linearization design methodology based on system parameter identification is discussed. Modern nonlinear servomechanism theory is adapted to cope with the hard nonlinearities inherent in the turret system. The mathematical models of electrical turret driving system to develop a high performance control algorithm are derived, and the parameter estimation algorithm identifying the unknown system parameters such as vicious and coulomb frictions, stiffness and inertia is developed. Through computer simulation and experiments, it is shown that pointing and tracking accuracy and stabilization against the wideband stochastic disturbance induced by vehicle running on the bump course are improved. Therefore, it is considered the proposed nonlinear control technique is effective in counteracting the nonlinearities and disturbances.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.9
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• pp.840-846
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• 2004

In this study, the performance of a heavy load pointing system has been investigated. The PI controller are being widely used in industrial application because of simple, cheap, and excellent performance. However, the requirement for control precision becomes higher and higher, as well as the plants becomes more and more complex. In order to achieve the satisfied control performance, we have to consider the affection of nonlinear factor contained in plant. In this paper, the neural-PI control law have been evaluated. The proposed controller is compared with the existing controllers through simulations, and the results show that the pointing accuracy of the proposed control system is improved against the disturbance induced by vehicle running on the bump course.

• Journal of the Korea Institute of Military Science and Technology
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• v.1 no.1
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• pp.65-81
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• 1998

Objective technology development has been carried out aiming performance improvement of the stabilized gun-pointing system for Type-4 tank. The full nonlinear simulation programs with gun bending modes and nonlinearities were developed to estimate, analyze and design the driving and stabilization system, and validated through the comparisons between simulations and test results of the existing Type-1 tank. The prototype is designed, fabricated, tested and evaluated on the test range as well as in the laboratory and followed by development and operational tests. The performance test results on stationary and on-the-move conditions are turned out to be superior to those of the advanced tanks developed in foreign countries.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.971-976
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• 1996

A flexible pointing system mounted on top of a vehicle suffers from performance degradation due to bending vibrations as the vehicle runs on a bump course. In order to improve the pointing performance, the pointing structure's vibrations should be suppressed. In this paper, a nonlinear controller is designed to control the tip position of the pointing system while actively suppressing the vibrations. To cope with high order dynamics and nonlinearities of the plant and hydraulic actuating system, a two-stage sliding mode controller is devised. The desired actuating pressure is obtained in the first stage and then the in put current In the hydraulic servo system is computed to generate the pressure. The simulation results show the effectiveness of this scheme and improvements in pointing accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.55-63
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• 2004

This paper presents neural network based controller using the feedback error loaming technique for a heavy load pointing system. Also the mathematical model was developed to analyze heavy load pointing system. The control scheme consists of a feedforward neural network controller and a fixed-gain feedback controller. This neural network controller is trained so as to make the output of the feedback controller zero. The proposed controller is compared with the conventional PI controller through simulations, and the results show that the pointing accuracy of the proposed control system are improved against the disturbance induced by vehicle running on the bump course.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.12
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• pp.2048-2055
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• 2001

This paper develops a computational model for estimating the ride quality of a cabover type large-sized truck in a double wheel bumpy ride test. The computational model is developed using ADAMS. To verify the developed model, an actual vehicle double wheel bumpy ride test is performed. In the test, the vehicle maintains a straight course with a constant velocity such that the front two wheels are passed the bump at the same time. The bump has the height of 60mm, and the width of 550mm. In the test, four velocities are used. They are 10kph, 20kph, 30kph and 40kph. Since the large-sized truck's center of gravity location is high, and its weight is heavy, it is a quite severe test condition to perform the test with more than 30kph velocity. In the test, vertical accelerations on the floor of the cab are measured. The measured accelerations are compared to the simulation results. From the comparison, it is shown that the developed model can predict not only the measured acceleration's tendency but also peak accelerations quite well. In this paper, the validated model is utilized to compare the ride quality between a vehicle with a multi-leaf spring and a vehicle with a tapered leaf spring in the front suspension system in a double bumpy ride test.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.227-233
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• 2015

In this study, an indoor test environment was developed for studying the vision stabilizer of an unmanned vehicle, using a virtual environment and a 6-axis motion simulator. The real driving environment was replaced by a virtual environment based on the Aberdeen Proving Ground bump test course for military tank testing. The vehicle motion was reproduced by a 6-axis motion simulator. Virtual reality driving courses were displayed in front of the vision stabilizer, which was located on the top of the motion simulator. The performance of the stabilizer was investigated by checking the image of the camera, and the pitch and roll angles of the stabilizer captured by the IMU sensor of the camera.