Kab-Jin Jun

A Study on the Fatigue Life Prediction of OHT Vehicle Structures Using the Modal Stress Recovery Method

In this paper, a computer aided analysis method is proposed for a durability assessment in the early design stages using the Modal Stress Recovery (MSR) and the linear damage rule. From a dynamic analysis of the OHT vehicle system with some flexible bodies, modal displacement time histories of vehicle structure components are calculated. From finite element analysis of components, modal stresses are calculated. With the modal displacement time history and the modal stress of the component, the dynamic stress time history at the critical location is produced using the superposition principle. Using the linear damage rule and the cycle counting method, the fatigue life is predicted from the dynamic stress time history. The process of predicting the fatigue life using the proposed computer models in this paper may be applied to structures of various dynamic systems.Copyright

Study of Factor Causing Wear of a Barrel Cam in a Paper-Cup-Forming Machine by Using Multibody Dynamics Model

The barrel cam, which is a type of cylindrical cam, has been widely used as a part of index drive units for automatic manufacturing machines. The axis of rotation of the barrel cam is orthogonal to the axis of rotation of the follower. The index drive rotates or dwellsdepending on the cam profile, while the cam rotates with a constant velocity. Continuous sliding contact between the barrel cam and the follower surfaces causes wearing of the adhesive between them. This study shows that the contact force between two sliding bodies is responsible for the wear of the barrel cam in the paper-cup-forming machine. This contact force is calculated by using the multibody dynamics model of the paper-cup-forming machine. The analytical result is validated by comparing it to the actual wear spots on the real product.

Design and Optimization of Intelligent Service Robot Suspension System Using Dynamic Model

Key Words: Intelligent Service Robot(서비스용지능형로봇), Suspension System(현가시스템), DynamicModel(동역학모델), Design Optimization(설계최적화)초록: 최근에, 서비스용지능형로봇이공공기관에서방문객들에게건물을안내하고정보를제공하는데사용되어지고있다. 이로봇은지면위치인식방식의센서를가지며마름모형태의네바퀴로스스로를지탱한다. 로봇의작동은구동부분과내부구조가하나의결합된몸체로구성되어있기때문에고르지못한장소에서는제한을받는다. 이와같은상태가지속되면로봇의정밀한부분에서이상징후가발견될것이고, 각각의연결부위가약화될것이다. 따라서로봇의동역학모델이만들어졌고, 서스펜션과함께구동특성들을위한모의실험도이루어졌다. 이서스펜션시스템은로봇의각부분에미치는충격들을줄이는데최적화되었다.Abstract: Recently, an intelligent service robot is being developed for use in guiding and providing information tovisitors about the buildingat public institutions. The intelligent robot has a sensor at the bottomtorecognize its location.Four wheels, which are arranged in the form of a lozenge, support the robot. This robot cannot be operated on unevengroundbecauseitsdrivingparts areattachedtoits mainbodythat containstheimportant internal components. Continuousimpact with the ground can change the precise positions of the components and weaken the connection between eachstructural part. In this paper, the design of the suspension system for such a robot is described. The dynamic model ofthe robot is created, and the driving characteristics of the robot with the designed suspension system are simulated.Additionally, thesuspensionsystemisoptimizedtoreducetheimpactfortherobotcomponents.

Numerical Simulation of the Power Shift Drive (PSD)-Axle in the Forklift

In this study, a new concept of power delivery system is developed. Power Shift Drive (PSD)-Axle vehicle modeling and dynamic movement analysis are performed by simulation. The dynamic vehicle model is constructed from data obtained from the derived equation, considering the specific characteristic of each part. The model is composed of a torque converter, a gear box, a differential, hub reduction and an engine, which is the power source of the 1st forward and reverse PSD-Axle, as the principle parts. By unifying the mathematical equation of each component, a mathematical model of the 1st forward gear is derived. The system dynamic model is created using Matlab/Simulink based on the mathematical model. Simulation is carried out using simulink to estimate the dynamic behavior of the PSD-Axle. Also, the dynamo test result is used to verify the reliability of the system dynamic model. This study can be used to establish the basic design concept for the forward and reverse PSD-Axle multi gear system.Copyright