• Korean Journal of Computational Design and Engineering
• /
• v.3 no.1
• /
• pp.40-47
• /
• 1998

Recently, the various driving simulator have been used widely to analyze the handling performance of vehicle and to verify the motion control algorithm of vehicle. In this study, a virtual driving simulator based on the 20-DOF vehicle model is realized to estimate the handling performance and stability of a 4WS (Four-wheel-steering) and/or 4n(Four-wheel-driving) vehicle. Especially the DC motor controlled 4WS actuator is modelled in order to reflect the effect of the responsiveness of actuator on the handling performance and stability. And the realized simulator can be applied to develope a real time simulation system for designing and testing the real vehicles.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.987-988
• /
• 2008

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.4
• /
• pp.313-320
• /
• 2011

Multi-axle driving vehicles that are used in special environments require high driving performance, steering performance, and stability. Among these vehicles, 6WS/6WD vehicles with middle wheels have structural safety by distributing the load and reducing the pitch angle during rapid acceleration and braking. 6WS/6WD vehicles are favored for military use in off road operations because of their high maneuverability and mobility on extreme terrains and obstacles. 6WD vehicles that using in-wheel motor can generate the independent wheel torque without other mechanical parts. Conventional vehicles, however, cannot generate an opposite driving force at each side wheel. Using an independent steering and driving system, six-wheel vehicles can show better performance than conventional vehicles. Using of independent steering and driving system, the 6 wheel vehicle can improve a performance better than conventional vehicle. This vehicle enhances the maneuverability under low speed and the stability at high speed. This paper describes an independent 6WS/6WD vehicle, consists of three parts; Vehicle Model, Control Algorithm for 6WS/6WD and Simulation. First, vehicle model is application of TruckSim software for 6WS and 6WD. Second, control algorithm describes the optimum tire force distribution method in view of energy saving. Last is simulation and verification.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.11
• /
• pp.1201-1206
• /
• 2014

This paper presents the development of an event-based operator model of a wheel loader for virtual V-pattern working. The objective of this study is to analyze the performance and dynamic behavior of the wheel loader for a typical V-pattern. The proposed typical V-pattern working is divided into four stages. The developed operator model is based on eight events, and the operator's inputs are occurred sequentially by event. A 3D dynamic simulation model of the wheel loader is developed and used to analyze the dynamic behavior during working, and the simulation results are compared with the experimental data of V-pattern working. The proposed 3D dynamic simulation model and operator model are constructed using MATLAB/Simulink. The proposed operator model for V-pattern working is expected to enable evaluation of the working performance and dynamic behavior of the wheel loader.

• International Journal of Precision Engineering and Manufacturing
• /
• v.8 no.1
• /
• pp.32-37
• /
• 2007

The outer diameter finishing grinding process required for ferrules, which are widely used as fiber optic connectors, is carried out by high-precision centerless grinding machines. In this study, the thermal characteristics of such a machine, for example, the temperature distribution, temperature rise, and thermal deformation, were estimated based on a virtual prototype and the heat generation rates of heat sources related to normal operating conditions. The prototype consisted of a concrete-filled bed. hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The reliability of the predicted results was demonstrated using temperature characteristics measured from a physical prototype. The predicted and measured results indicated that this particular high-precision centerless grinding machine had very stable thermal characteristics.

• Journal of the Ergonomics Society of Korea
• /
• v.29 no.2
• /
• pp.249-255
• /
• 2010

The visibility evaluation is significant for the development of construction equipment. The visibility evaluation follows the standards of ISO 5006, ISO 14401-1, and ISO 14401-2. The evaluation contains the operator's visibility and the visibility of rear-view mirrors. The operator's visibility includes the visibility test which requires the recognition of the rectangular line surrounding the machine by one meter and the circle with a 12 meter radius. This study describes the two evaluation processes for the development of the wheel loader. The first process is the light bulb shadow test by using a prototype wheel loader. The second process is based on computer simulation in virtual space. The advantages and disadvantages of computer simulation process are investigated.

• International Journal of Precision Engineering and Manufacturing
• /
• v.7 no.4
• /
• pp.34-39
• /
• 2006

High-precision centerless grinding machines are emerging as a means of finishing the outer diameter grinding process required for ferrules, which are widely used as fiber optic connectors. In this study, a structural characteristic analysis and evaluation were carried out using a virtual prototype of a centerless grinding machine to realize systematic design technology and performance improvements required to manufacture ferrules. The prototype consisted of a concrete-filled bed, hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffness values of the centerless grinding machine were estimated based on the relative displacements between the GW and RW caused by grinding forces. The simulated results illustrated that a concrete-filled bed considerably improved the structural stiffness and accuracy of a high-precision centerless grinding machine.

• Korean Journal of Computational Design and Engineering
• /
• v.5 no.4
• /
• pp.312-318
• /
• 2000

In this study, an exclusive CAD/CAM system is developed for enhancing the effectiveness and productivity of CNC universal cylindrical grinding machines on which the external/facing/internal grinding cycles and the wheel dressing cycles are integratively carried out. The CAD/CAM system can manage the various processes such as geometry design, NC code generation, NC code verification, DNC operation, and so on. Especially, the feature-based modeling concept is introduced to improve the geometry design efficiency. And the NC code verification is realized by virtual manufacturing technique based on the real-time analysis of NC codes and the boolean operation between workpiece and wheel.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.1
• /
• pp.45-55
• /
• 2013

With the recent advancement of control method and battery technology, the electric vehicle have been researched to replace the conventional vehicle with electric vehicle with the view point of the environmental concerns and energy conservation. An electric vehicle which is equipped with the independent front steering system and in-wheel motors has advantage in terms of control. For example, the different torque which generated by left and right wheels directly can make yaw moment and the independent steering using outer wheel control is able to reduce the sideslip angle. Using of independent steering and driving system, the 4 wheel electric vehicle can improve a performance better than conventional vehicle. In this paper, we consider the method for improving the cornering performance of independent front steering system and in-wheel motor used electric vehicle with the compensated outer wheel angle and direct yaw moment control. Simulation results show that the method can improve the cornering performance of 4 wheel electric vehicle. We also apply the steering motor failure to steer the vehicle turned by the torque difference without steering. This paper describes an independent front steering and driving, consist of three parts; Vehicle Model, Control Algorithm for independent steering and driving and simulation. First, vehicle model is application of TruckSim software for independent front steering and 4 wheel driving. Second, control algorithm describes the reduced sideslip and direct yaw moment method in view of cornering performance. Last is simulation and verification.

• Journal of Biomedical Engineering Research
• /
• v.38 no.4
• /
• pp.197-204
• /
• 2017

The aim of this study was to evaluate driving performance of normal subjects for controlling the steering wheel by using foot operated steering devices in the driving simulator. Many people with complete bilateral loss or loss of use of upper limbs but with normal lower limbs are frequently left without use and/ or control of their hands, arms, or the upper extremities of their bodies. As a result, persons disabled in this manner have problems in operation an automobile because they cannot grasp and manipulate a conventional steering wheel. Therefore, if foot operated steering devices are used for controlling the vehicle on in people with disabilities, the disabled people could improve their community mobility by driving a car safely. Ten normal subjects were involved in this research to evaluate steering performance by using three types of steering devices(conventional steering wheel, pedal type foot steering, circular type foot steering) in driving simulator. STISim Drive 3 program was used for testing the driving performance in two road scenarios: straight road and curved road at low and high speed of vehicle (40 km/h and 80 km/h). This study used two-way ANOVA to compare the influences of two factors(type of foot steering device and road scenario) in the three dependent variables of steering performance(standard deviation of lateral position, the lateral position of vehicle and the number of line crossing). The average values of the three dependent variables(standard deviation of lateral position, lateral position and the number of line crossing) of driving performance were significantly smaller for conventional steering wheel or pedal type foot steering than circular type foot steering.