Wheeled inverted pendulum (WIP) systems provide agile motion and energy-efficient locomotion through the wheels. However, they suffer from undesirable wheel motion for the acceleration and change of friction by the surface conditions. This paper presents a wheeled inverted pendulum with a fan (WIPF) that incorporates a fan thrust for the additional force for the control of traditional WIP systems. The WIPF is fully actuated by the wheel torque and the fan thrust, enabling the system to achieve enhanced balancing. The dynamics of the proposed system are analyzed and modeled for the control of the system with a linear quadratic regulator (LQR). The performance and characteristics of the WIPF are studied by simulations and experiments. WIPF showed enhanced balancing in step response for a desired position and improved impact robustness. Moreover, it achieved simultaneous control of the wheel position and body tilt angle, which is not attainable in traditional WIP systems.

In this study, the abnormal noise phenomenon generated intermittently in the shock absorber of the combat armored vehicle was approached from the side of the squeak joint to solve the phenomenon. In order to identify the cause of the noise, the factors causing friction in the shock absorber were checked from the viewpoint of problem product analysis, process, and design. As an improvement plan, by improving the non-lubricated section in the nitrogen chamber, the operating noise was reduced to a level lower than that of a general automobile engine along with the elimination of noise. Considering that this is a combat vehicle, it is judged that it has been improved so as not to affect the survivability and health of the crew during equipment operation. Through the improvement of this study, it is expected to prevent power loss and improve the emotional quality of our soldier.

The rear door of the wheeled armored vehicle is a part that provides a passage for the crew to get on and off when it is opened and plays a role in forming watertightness and airtightness when it is closed. A case where the rear door was deformed during the rear door opening/closing operation occurred. The rear door should be improved because when it has been deformed, it is impossible to form watertight and positive pressure so that damage for humans and repair cost may occur. Therefore, in this paper, the causes of deformation were analyzed, and improvement plans were derived in order to prevent the deformation of the rear door of wheeled armored vehicles. In addition, a verification test was conducted to evaluate the appropriateness of the improvement plans.

ROPS is a structure installed to protect drivers from tractor rollover accidents and is being tested for certification under the OECD code. Because this test requires a lot of cost and time to develop the ROPS and to produce test model, the OECD is discussing the introduction of virtual test using finite element analysis. In this study, the results were compared by conducting a strength test and finite element analysis applied with the OECD code to use it as a basic data for standardization of ROPS virtual test methods. It was confirmed that the results of the analysis of the bolts and plates of the coupling part and the folding part were more close to the physical test results than the rigid elements and constraints at the point of coupling the tractor and ROPS.

In this paper, the goal is to obtain a dynamic model of a particular system. The system is a combination of a wheeled vehicle(chassis) with a turret rotating in azimuth direction and a gun rotating in a elevation direction. At this time, the motion of the gun according to the shaking of the continuous shot is obtained using the coordinate transformation equation in the azimuth and elevation angle. Also, the dynamic model for the swaying of wheeled vehicle is obtained through the Lagrange’s equation. Through this, we analyze the tumbles of the gun, whiat is the major term, and what dynamics are needed for stabilization control.

The vibration of wheel is mainly affected by a fault on a wheel contacting with railway when average speed is over 60km/h. When the wheel vibration caused by wheel scratch increase more than a certain criterion, the wheel is shaved to reduce the vibration. This criterion of shaving is determined from the acceleration signal measured from the sensor mounted on the railway. In this study, vibration characteristics of the rolling wheels having a fault is analyzed with experimental approach to verify the acceleration criterion for shaving wheel.

본 연구에서는 콘크리트 포장에 덧씌우기를 하였을 때 다축차륜하중에 의한 응력분포특성을 분석하기 위하여 변환영역에서의 해석법을 개발하였다. 덧씌우기는 기존의 슬래브와 완전히 부착이 되었을 경우와 전혀 부착이 되지 않았을 때의 두 가지 극한 조건을 기준으로 분석을 하였다. 차륜하중은 복륜단축, 복륜복축, 복륜삼축 등 복륜다축하중을 고려하였으며 덧씌우기의 두께, 탄성계수, 포아송비 등이 응력분포에 미치는 영향을 분석하였다. 변환영역에서의 해석법을 이용하여 덧씌우기 포장을 분석하는 방법에 대하여 상세히 설명하였으며 해석결과의 정확성은 유한요소법을 이용한 해석결과와 비교하여 검증하였다. 해석을 수행한 결과 덧씌우기의 두께, 탄성계수, 포아송비의 증가는 기존 슬래브 하부의 최대인장응력을 감소시키며 감소 정도는 부착 덧씌우기가 비부착 덧씌우기에 비해 더 큰 것을 알 수 있었다. 또한 덧씌우기의 포아송비가 응력에 미치는 영향은 그리 크지 않은 것을 알 수 있었으며 부착과 비부착 덧씌우기 포장에서 덧씌우기의 두께 및 탄성계수의 증가에 따른 기존슬래브의 최대응력 감소특성도 분석하였다. 그리고 하중의 축수에 따른 부착과 비부착 덧씌우기 포장의 응력분포 및 최대응력특성도 분석하였다.

Korea Railroad Research Institute(KRRI) has developed the rubber-tired AGT system from 1999 to 2004. The rubber-tired AGT vehicle is now on test for its performance and function in the Gyeong-San test line. In this paper, we provide the reliability management plan to assure required the RAMS(reliability, availability, maintainability 8t safety) of the AGT vehicle system.

Korea Railroad Research Institute(KRRI) has developed the rubber-tired AGT system from 1999 to 2004. The rubber-tired AGT vehicle is now on test for its performance and function in the Gyeong-San test line. Tn this paper, we provide the reliability management plan to assure required the RAMS(reliability, availability, maintainability & safety) of the AGT vehicle system.

본 논문에서는, 고속철도용 슬래브 궤도의 동특성을 파악하여 소음.진동 대책을 마련하기 위한 기초자료를 제시하기 위해 차륜과 레일의 상호작용을 고려한 슬래브 궤도의 진동해석을 수행하였다. 해석시 열차의 스프링아래 질량은 Hertzian스프링을 통해 레일과 접촉하는 것으로 가정하였으며, 궤도는 2중 탄성지지보로 모델링 하였다. 연구결과 궤도지지계의 탄성, 질량 및 강성 등을 적절히 조절하므로서 궤도에 발생하는 진동 및 하부구조물로 전달되는 분포력을 감소시킬 수 있음을 알 수 있었다.

Odometry using wheel encoder is a common relative positioning technique for wheeled mobile robots. The major drawback of odometry is that the kinematic modeling errors are accumulated when the travel distance increases. Therefore, accurate calibration of odometry is required. In several related works, various schemes for odometry calibration are proposed. However, design guidelines of test tracks for odometry calibration were not considered. More accurate odometry calibration results can be achieved by using appropriate test track because the position and orientation errors after the test are affected by the test track. In this paper, we propose the design guidelines of test tracks for odometry calibration schemes using experimental heading errors. Numerical simulations and experiments clearly demonstrate that the proposed design guidelines result in more accurate calibration results.

An augmented state feedback controller for a Wheeled Inverted Pendulum (WIP) is proposed in this research. The augmented state feedback controller is able to keep the WIP returning to the origin. Generally, the WIP has both stable and unstable equilibrium points. To keep the WIP over the unstable equilibrium point, the WIP consistently is being controlled. A simple state feedback controller is letting the WIP out of the origin when the center of gravity of the WIP locates out of the schematic center line. In some case of applications, it may not be desirable that the WIP is drifting out of the initial location. The proposed augmented state feedback controller is able to keep the WIP at the initial location whether its center of gravity lies out of the center line or not. Numerical simulations are carried out to show the validation of the augmented sated feedback controller.