• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.10
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• pp.958-966
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• 2007

This study presents full vehicle dynamics model for the dynamic characteristic analysis of chassis parts which are suspension and brake system. This vehicle dynamics model is appled to kinematics and quasi-static analysis for each chassis part. In order to develop the vehicle dynamics model, the parameters of each chassis element part which are bush, spring and damper are measured by experiment. Also the wheel forces and moments of 6 DOF are measured at each wheel center. These data are applied to input parameter for vehicle dynamics model. And the verification of the developed model is achieved to comparison with the experimental force data of spring, trailing arm and assist arm by using the load response by strain gauge. These experimental force data are acquired by road test at event surfaces of P/G which are belgian and chuck holes roads.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.155-166
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• 1997

In this study, a simulation tool is developed in order to investigate non steady-state cornering performance of 6WD/6WS special-purpose vehicles. 6WD vehicles are believed to have good performance on off-the-road maneuvering and to have fail-safe capabilities. But the cornering performances of 6WS vehicles are not well understood in the related literature. In this paper, 6WD/6WS vehicles are modeled as a 18 DOF system which includes non-linear vehicle dynamics, tire models, and kinematic effects. Then the vehicle model is constructed into a simulation tool using the MATLAB /SIMULINK so that input/output and vehicle parameters can be changed easily with the modulated approach. Cornering performance of the 6WS vehicle is analyzed for brake steering and pivoting, respectively. Simulation results show that cornering performance depends on the middle-wheel steering as well as front/rear wheel steering. In addition, a new 6WS control law is proposed in order to minimize the sideslip angle. Lane change simulation results demonstrate the advantage of 6WS vehicles with the proposed control law.

• International Journal of Automotive Technology
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• v.7 no.2
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• pp.209-216
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• 2006

A study has been conducted for an optimal processing and an apparatus for manufacturing a laser welded tube for one-body formed bumper beam. The tube dimensions used in calculation were the thickness of 1.4 mm, the diameter of 105.4 mm and the length of 2000 mm. The tube was formed of a cold rolled high strength steel plate(tensile strength of 600 MPa). The two-roll bending method was the optimal tube forming process in comparison with the UO-bending method, the bending method on the press brake, the multi-step continuous roll-forming method and the 3-roll bending method. Monitoring of the welding quality was conducted and the seam tracking along the butt-joint lengthwise to the tube axis was also examined. The longitudinal butt-joint was welded by using a $CO_2$ laser welding machine equipped with a seam tracker and a plasma sensor. The $CO_2$ laser tube welding machine could be used for precise seam tracking and real-time monitoring of the welding quality. As a result, the developed laser welded tube could be used for a one-body formed automobile bumper beam.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.4
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• pp.241-246
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• 1998

It is well known for 410L ferritic stainless steel powder to applicate a sensor ring in anti-lock brake system of automobile, several studies, because of its excellent magnetic properties. This study was carried out to investigate the magnetic properties such as the maximum magnetic induction, coercivity and maximum permeability of the materials with functions of sintering density, time and temperature, and concluded as follows: 1. Sintering under the circumstances of Ar gas and the temperature of $1250^{\circ}C$ for 60min, showed that nitrogen was increased, whereas carbon and oxygen decreased in quantities. 2. Both maximum magnetic induction value of 4700Gauss and permeability of 200 were obtained at the maximum sintering density of $6.89g/cm^2$. Here, the properties showed a linear increasement with increasing the sintering density. 3. Coercivity sharply decreased with incresing the sintering density and reached to 7.6Oe at the maximum sintering density of $6.89g/cm^2$.

• The KSFM Journal of Fluid Machinery
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• v.18 no.3
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• pp.60-65
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• 2015

This paper deals with performance characteristics and efficiencies of Pelton turbine can be applied as one of ERDs (Energy Recovery Devices) of PRO (Pressure Retarded Osmosis) system for desalination. The objective of this study is experimentally estimating the performance of micro-scale Pelton turbine for PRO pilot plant. Especially the performance characteristics with variations of jet nozzle diameter of Pelton turbine are discussed in detail. In order to do this, lab scale test rig of Pelton turbine was made for performance test, which includes water tank, Pelton wheel with buckets, jet nozzle and torque brake and so on. The parameter effects related on Pelton turbine's efficiency were investigated and discussed on the influence of the variations of load and speed ratio.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.1
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• pp.33-39
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• 2014

Automatic driving needs many functions such as the obstacle recognition, the lane recognition, and the lane change, etc. In this paper, we realized a system which automatically drove the three-kinds of vehicle driving course, to introduce and apply the concept of 'color recognition' that expands the scope of 'lane recognition' for vehicle driving. We made the reduced each course compared with RC(Radio Control) car size, and controlled the steering considering the position and the slope of the detection line and the speed. Because the RC car does not have the brake function, we consider the speed and the position of the detection line to stop the RC car.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.7
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• pp.632-638
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• 2010

This paper presents an optimum tire force distribution method for 6WD/6WS(6-Wheel-Drive and 6-Wheel-Steering) electric vehicles. Using an independent steering and driving system, the performance of 6WD/6WS vehicles can be improved, as, for example, with respect to their maneuverability under low speed and their stability at high speed. Therefore, there should be a control strategy for finding the optimum tire forces that satisfy the driver's command and minimize energy consumption. From the driver's commands (steering angle and accelerator/brake pedal stroke), the desired yaw moment, the desired lateral force, and the desired longitudinal force were obtained. These three values were distributed to each wheel as the torque and the steering angle, based on the optimum tire force distribution method. The optimum tire force distribution method finds the longitudinal/lateral tire forces of each wheel that minimize the cost function, which is the sum of the normalized tire forces. Next, the longitudinal/lateral tire forces of each wheel are converted into the reference torque inputs and the steering wheel angle inputs. The proposed method was tested through a simulation, and its effectiveness was verified.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.519-524
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• 2004

This study is concerned with the braking distance estimation using frictional energy rate. First, steady state rolling analysis is performed, and using this result, the braking distance is estimated. Dynamic rolling analysis during entire braking time period is impratical, so that this study divides the vehicle velocity by 10km/h to reduce the analysis time. The multiplication of the slip rate and the shear stress provides the frictional energy rate. Using frictional energy rate, total braking distance is estimated, In addition, ABS(Anti-lock Brake System) is considered, and two type of slip ratios are compared, One is 15% slip ratio for the ABS condition, and the other is 100% slip ratio which leads lo the almost same braking distance as the elementary kinematic theory. A slip ratio is controlled by angular velocity in ABAQUS/Explicit, A 15% slip ratio gives the real vehicle's braking distance when the frictional energy occurred al disk pad is included. Disk pad's frictional energy rate is calculated by the theoretical approach.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.61-65
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• 2014

Construction heat insulating material for construction is used in large amounts in industry. In the manufacturing process of this insulation material, a thermal insulation material is completed while a polymer in a liquid state passes through Hall breaker. At this time, the quality and form of a product are determined by a hole in the breaker according to the oil pressure of the fluid and the change of the flow velocity. The friction wear action with regard to partner movement between the two levels of quality of materials affects the performance and the lifetimes of machine parts. In this study of a friction test, SM45C, which is a material used to create brake holes, was used. PVC was used to create the specimen. Moreover, an experiment divided a lubricous state and an unlubricated condition. The resulting value over the load of a pin, the revolving speed of a disk, and the standby state of an experimental result disk could be acquired.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.72-80
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• 2013

This study is to develop and evaluate an AFS and an ARS controllers to enhance lateral stability of a vehicle. A sliding mode control (SMC) and a fuzzy logic control (FLC) methods are applied to calculate the desired additional steering angle of AFS equipped vehicle or desired rear steer angle of ARS equipped vehicle. To validate AFS and ARS systems, an eight degree of freedom, nonlinear vehicle model and an ABS controllers are also used. Several road conditions are used to test the performances. The results showed that the yaw rate of the AFS and the ARS vehicle followed the reference yaw rate very well within the adhesion limit. However, the AFS improves the lateral stability near the limit compared with the ARS. Because the SMC and the FLC show similar vehicle responses, performance discrimination is small. On split-${\mu}$ road, the AFS and the ARS vehicle had enhanced the lateral stability.