• Journal of Korean Institute of Industrial Engineers
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• v.28 no.1
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• pp.25-35
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• 2002

This paper presents a heuristic algorithm that a mobile robot avoids obstacles using optical flow. Using optical flow, the mobile robot can easily avoid static obstacles without a prior position information as well as moving obstacles with unknown trajectories. The mobile robot in this paper is able to recognize the locations or routes of obstacles, which can be detected by obtaining 2-dimensional optical flow information from a CCD camera. It predicts the possibilities of crash with obstacles based on the comparison between planned routes and the obstacle routes. Then it modifies its driving route if necessary. Driving acceleration and angular velocity of mobile robot are applied as controlling variables of avoidance. The corresponding simulation test is performed to verify the effectiveness of these factors. The results of simulation show that the mobile robot can reach the goal with avoiding obstacles which have variable routes and speed.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.207-213
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• 1999

In this study, the possibility of estimation of friction coefficient between tire and road surface using running car data are checked. To get necessary data, such as tire and car velocities and braking force, a test car is driven with certain magnitude of decelerations from pre-set initial velocities to stop . The data are used to estimate friction coefficient with property chosen parameters , e.g,, driving stiffness, pressure distribution functions, etc. Experimental results show that running data car be used with properly chosen parameters to estimate friction coefficient.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.24-30
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• 2013

This paper studies the comparative analysis on two different internal cushion devices (the types of needle and relief valve) used to absorb the energy which is generated when the pneumatic cylinder moves with the load at meter-out speed control system. The effect at varying the piston velocity under same driving condition is mainly investigated. The simulation results on pressure in the cushion chamber and the dynamic behavior of the relief valve type cushion device are compared with the needle valve type. Design and performance are improved with the cushion configuration of better quality at high-speed pneumatic cylinder. Based on the relation between absorbed energy and impact energy at cushion process, cushion performance at pneumatic cylinder is evaluated.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.921-927
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• 1988

The process and results of computer simulation using bond graphs for a hydraulic system driving large rotational inertia are presented in this paper. As the large rotational inertia and its application characteristics, control criteria of this system is not position-control nor velocity-control but appropriate acceleration, deceleration and inching ability. All the components' nonlinear characteristics are modelled using bond graphs. The equationing and solution process is carried out by a package. Finally it is concluded that modelling of this kind of system by bond graphs and using a software as its solver shows good approximated results to actual experimental data, and that the proposed modelling may be useful to actual design process for this kind of hydraulic system.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.75-80
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• 2004

Feasibility of the small capacity fuel cell powered vehicle is carried out for system design with loading characteristics. The major design concepts which include battery, driving motor, and fuel cell module are analyzed and discussed for the future development. A load characteristics program is developed in order to calculate the traction power of fuel cell vehicle according to the driving courses specified. Further, the small capacity fuel cell vehicle is analyzed to determine the capacity of stack as a function of the velocity for an appropriate power required.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.11
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• pp.1096-1103
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• 2010

This paper proposes CDC (Continuous Damping Control) algorithm and verifies in multi-body dynamic vehicle. In order to distinguish a road profile on driving, waviness calculated by the filtered vertical-accelerations of sprung and unsprung masses is introduced. Sky-hook control is used at a low waviness road and constant damping level control is used at a high waviness road, where the hard damping level is determined by waviness, roll rate, acceleration, and deceleration. The damping levels of ride, anti-roll, anti-squat, and anti-dive modules are calculated by tuning parameters which is dependent upon vehicle velocity. Therefore this high tunable algorithm is useful to improve the ride and handling performance under various driving conditions. In the simulations, tire and dampers are modelled by SWIFT (Short Wavelength Intermediate Frequency Tire) model and 1st order delay model, and results are compared with conventional damper's.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.137-144
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• 1998

For a model system consisted of four pneumatic cylinders with strokes of 10, 20, 40 and 80 mm, investigation was carried out experimentally and numerically about the reliability of system with elastic and viscous load. The elastic load affects the performance of each cylinder in cylinder series, and changes the time lag and the velocity of the piston which makes the positioning control rather difficult. Taking the effects of the elastic load into consideration, positioning can be carried out comparatively smoothly by only adjusting the driving timing. The effect of a viscous load reduces the vibration of each moving body in the cylinder series and also reduces the over-travelled distance which happens when several cylinders move at the same time. For reasons, a positioning with a viscous load can be relatively smoothly carried out even without the timing control.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.76-82
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• 2014

In this paper, an optimal power distribution algorithm is proposed for the small electric vehicle with front in-line and rear in-wheel motors. First, it is assumed that the vehicle driving torque and velocity are given conditions. And, an optimal problem is defined that finding the front and rear motor torques which minimizes the battery power. From the above optimization problem, the optimized front-rear motor torque distribution map is obtained. And, the vehicle simulations are performed to verify the performance of the optimal power distribution algorithm which is proposed in this study. The simulations are performed based on the federal urban driving schedule for two cases which are constant ratio power distribution, and optimal power distribution. From the simulation results, it is found that the optimal power distribution shows the 6.3% smaller battery energy consumption than the constant ratio power distribution.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.506-512
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• 1997

Ultrasonic knives have been successfully used for the surgery of many medical fields. However, the conventional ultrasonic knives for surgical operation cannot be controlled its resonant frequency. So if the material to cut has different characteristic impedance then different ultrasonic knife will be needed. Because the optimum driving frequency of ultrasonic knife is different by characteristic impedance of material. In this work, using a frequency variable ultrasonic transducer made of multi-layered PZT vibrator, a frequency controllable ultrasonic knife will be suggested. The design and computation principles will be also derived. For this work, firstly, the characteristics of this ultrasonic knife will be analyzed by transmission line model equivalent circuit, and the free admittance characteristics and vibrational velocity distributions will be obtained. Secondly, we will design and make the frequency controllable electrical oscillator for driving this ultrasonic knife.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.452-456
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• 2009

This paper presents a method for precisely localizing and parking of bimodal trams. In order to gam an automatically driving system for bimodal trams, precise up-to-date localization, velocity recognition, distance to next station and precise parking location estimation functions are required. This paper proposes a system consisting of control device, steering device, sensor input equipment, driving system, tachometer, vehicle-side sensors, magnetic markers and magnetic sensors. The tram recognizes the precise location via magnetic markers containing information. Parking position and precise distance calculation is embodied by a tachometer. The vehicle-side sensors are used to assure safe station approaching and parking magnetic markers provide improvement of precision while tram parking. This paper provides a system realizing localization and precise parking and afterwards the automatic drive test results are reported and analyzed.