• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.3
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• pp.132-138
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• 2011

This paper presents an intelligent control approach for lateral position control of an autonomous four wheel steered snowplowing robotic vehicle. The vehicle is built for removing snow on the highway. Dynamics of the vehicle is derived and linearized for LQR control. Lateral position is controlled by the LQR method first, then the neural network control technique is introduced to improve tracking performances under the presence of load. The feasibility of using four wheel steering control is investigated by simulation studies of lateral position tracking of the Ford F-250 truck model. Performances of a LQR control method and a neural network control method under virtual snowplowing situation are compared.

• Journal of the Ergonomics Society of Korea
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• v.26 no.1
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• pp.39-46
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• 2007

The purpose of this study was to develop a comprehensive posture classification scheme considering the effects of external load and motion repetition as well as those of working posture. The scheme was developed based on a series of existing empirical studies dealing with postural classification scheme, effects of external load and motion repetition. Ranges of joint motions, external load and motion repetition were divided into the groups with the same degree of discomforts. Each group was assigned a numerical relative discomfort score of code on the basis of discomfort values for the neutral position of elbow flexion. The criteria for evaluating stress of working postures were proposed based on the four distinct action categories, in order to enable practitioners to apply appropriate corrective actions. The proposed scheme was compared with OWAS, RULA and REBA. The comparison revealed that while the proposed scheme and RULA showed similar results for the working postures with light external load and non-repetitive postures, the former overestimated postural load for postures with moderate or heavy external load and repetitive postures than the latter.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.951-956
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• 2011

As the evaluation of loading characteristic on tilting mechanism is the most important one of the function test of tilting mechanism, the changing characteristic of load must be investigated on tilting of carbody for both the static and running condition of train. In this study, we reduced the load of tilting mechanism by adjusting the interface of carbody and bogie such as the weight balance, level of underframe, height of leveling valve, height of axle box and center position of tilting actuator with the characteristic curve of load for optimal condition of the tilting mechanism obtained in the previous study. Furthermore, the factor and effect of the interfacial structures respecting the load of tilting mechanism was evaluated by analyzing the changing characteristic of load obtained in the process of adjustment of interfaces. From these data, we will propose the maintenance standards for interfacial structures and tilting mechanism in order to minimize the load of tilting mechanism by analyzing in detail the characteristic of load for the main factors of the interfacial structure effecting on the load of tilting mechanism.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.3
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• pp.337-342
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• 1998

In this paper the lubrication performances of line pivoted pad thrust bearing and point pivoted pad thrust bearing are studied by a numerical analysis. The running characteristic parameters such as nondimensional load carrying capacity nondimensional friciton power loss nondimensional flow rate and film thickness ratios are calculated for various circumferential pivot positions. The results provide a usdful data for the selection of pivot position in a pivoted and thrust bearing.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.28-31
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• 1988

This paper proposes a new linear adaptive position controller of DC servo motor. The proposed method can improve the drive performance and rapidly reject the state error caused by both parameter variations and force disturbance. The structure of this adaptive control method is based multiloop feedback control and model reference control. Simulation results are presented to verify the improved response when parameter variations and load disturbance give relatively significant effects to the servo system.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.327-331
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• 1992

In this paper, we propose dynamic hybrid control method which takes the manipulator dynamics into consideration and extend to two cooperating robots. The first step is the linearization of the manipulator dynamics and the second step is the design of position/force controllers for the linearized model which takes account of both the command response and the robustness of the controllers to modeling errors and disturbance. We also consider load sharing for each robot.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.4
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• pp.155-160
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• 2001

KS-code(KS B 0896) for nondestructive ultrasonic testing classifies the quality level by relative flaw size only. But flaw position is more important than the flaw size. Test blocks having artificial holes near surface show lower yield load than the blocks having deeply located holes from the surface. So, level calibration table was proposed for classifying the quality level of welded steel structures.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.193-196
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• 2000

ln this paper, we consider to apply of 2-DOF (Degree of Freedom) PID controller at D.C servo motor system. Many control system use I-PD, PIB control system. but the position control system have difficulty in controling variable load and changing parameter We propose neural network 2-DOF PID control system having feature for removal disturbrances and tracking function in the target value point.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.1
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• pp.136-144
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• 2004

In general a hydraulic system which uses a single rod hydraulic as an actuator is modeled as a nonlinear system and reveals uncertain Parameter characteristics such as the density variation of hydraulic oil and is subject to load variations and severe disturbances during operation. A variable design-parameter fuzzy PID controller is adopted to solve these undesirable internal and external problems and its effectiveness is verified through computer simulations for control performance and real time control possibility.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.161-166
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• 2001

The static characteristics of four-nozzle flapper valves are investigated with both constant flow and constant supply pressure. The ranges, in which linearization of these characteristics would be valid, are discussed. Linearized dynamic model is also derived. Numerical simulations of nonlinear dynamic model are carried out by HyPneu to make an assessment of the effect of input step size in both cases of no-load and blocked-load operation.