Sung-Pil Jung

Analysis and Control of the Flexible Multibody System Using MATLAB

In this paper, analysis and control of the flexible multibody system using MATLAB is presented. The equations of motion of a flexible body are derived in terms of the modal coordinate. The rigid-flexible multibody dynamic solver is developed. Finite element information required to analyze motion of flexible bodies is imported from ANSYS. The modified finite element data, such as modal mass matrix, modal stiffness matrix and constraint mode shapes, is calculated in the solver. Since the solver is developed using MATLAB, it is very easy to connect with SIMULINK which is widely used to control motion of the multibody system. Several simulations are implemented to verify the developed solver. A control example is carried out and the usefulness of the developed solver is demonstrated.

Vibration Test of Truck with Air Suspension & Development of Korean Type Air Suspension

A leaf spring suspension has been widely used since it can carry big load and its simplicity. But one major drawback is the poor ride performance because of the friction in the system and the high stiffness coefficient. To overcome these, an air spring suspension can be used. The air spring suspension system can improve the ride of the heavy vehicle significantly and also it can adjust the height to the loading and unloading. The road tests for the truck with the leaf spring suspension and air spring suspension are performed to compare the ride quality of the two systems. To develop the air spring suspension system tailored to the target truck, chassis development procedure using CAE has been applied.

Development of the Analysis Model for Overhead Contact Line and Pantograph by EN Standard

The evaluation of the contact loss of the catenary system is the highlight issue for the high-speed railway vehicle. In this paper, using the multibody dynamic analysis techniques including a flexible body, the simulation method of the catenary system is proposed. The pantograph and overhead contact line are developed by using rigid body and ANCF (Absolute Nodal Coordinate Formulation) beam elements, respectively. And relative motions are constrained by sliding joint. Using this analysis model, contact force and loss of contact are calculated according to vehicle speed. The results of the simulation are evaluated by EN 50318 that is the international standard with regard to validation of the dynamic interaction between pantograph and overhead contact line.© 2011 ASME

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