• Proceedings of the KSR Conference
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• 2002.10b
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• pp.807-819
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• 2002

The air spring is used in secondary suspension system for railway vehicle to reduce and absorb the vibration and noise. In this paper, the characteristics and durability test was conducted in laboratory by using servo hydraulic fatigue testing system to evaluate the reliability. And to guarantee the adaptation of this air spring, the ride comfort and air pressure variation were measured in train test. The experimental results show that the characteristics and durability of domestic development productions are obtained the good results and the stiffness of the air spring which had become 6 year over increased. Also, the dynamic characteristics of domestic and existing product agree well the results obtained.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.730-734
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• 2001

In this study in order to confirm the algorithms that are suggested from paper (I) as the experimental result, as the applied results of the hydraulic servo system are very strong a non-linearity of the fluid in the computer simulation, the real-time adaptive learning control algorithms is validated. The evolutionary strategy has characteristics that are automatically. adjusted in search regions with natural competition among many individuals. The error that is generated from the dynamic system is applied to the mutation equation. Competitive individuals are reduced with automatic adjustments of the search region in accord with the error. In this paper, the individual parents and offspring can be reduced in order to apply evolutionary algorithms in real-time as the description of the paper (I). The possibility of a new approaching algorithm that is suggested from the computer simulation of the paper (I) would be proved as the verification of a real-time test and the consideration its influence from the actual experiment.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.94-99
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• 2000

In this study applied the general controller into th 16bit ordinary controller and recommand the simulator features the real system's propeties without DSP(Digital Signal Processing)-card. This simulator is designed to be synchronized in real time using A/D(Analog-Digital) convert and D/A(Digital-Analong) convert. In this study DSP card which is usually used for complex calculation is replaced with personal computer and designed to control, control-force using with the 16-bit micro processor.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.122-132
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• 1999

This study describes a dynamic model of the hydroforming process which is used for precision forming of sheet metals. To help the controller design for the control of the forming pressure needed for this process as well as to investigate the effect of system parameters on the dynamic behavior, dynamic modeling is performed with emphasis on hydraulic servo system which actuates the forming machine. Since the model contains several unknown parameters, these were estimated via a least square parameter identification method. Based upon the identified model, a series of simulations were performed for various operating conditions. The results were compared with those of the experiments to verify the validity of the proposed model. The comparison study shows that the proposed dynamic model can describe dynamic behavior of the forming pressure of the hydroforming process to desirable accuracy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.74-80
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• 2006

This paper deals with the control and fault monitoring of a DDV hydraulic actuation system. A hydraulic servo system has a nonlinear dynamics of an orifice flow through a valve spool. A full nonlinear model for a DDV actuation system is driven, and linearized to a simple model which is convenient for a control loop and fault monitor design. A top level requirement on the performance and safety for the actuation system is introduced. A control system and fault monitoring structure which can meet these requirements are discussed. A simulation package for a DDV actuation system which has a triplex redundant structure is developed.

• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.139-146
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• 2004

Resent removal work for road signs has been labor intensive and required times since it has been done manually using shaving type equipment. While traditional process is conducting, there are traffic jams caused by the passing control, and happened unexpected accidents to workers working at dangerous road circumstance. Besides, in current shaving method, there are high potentialities on the air pollution as well as the explosive accident occurred by using a propane gas. So, as an alternative, we have studied to develop the automatic erasing equipment made up with a high pressure water-jet system and automatic control system, mobile system; Wate-rjet system consists of an intensifier and nozzles to give a high pressure and spray on the sign, and automatic control system is composed of one axis robot using a hydraulic servo actuator controlled by a lever, And as a mobile system, a truck plays an important role for the transport of equipment and the forward movement in a removal process. In this paper, we have analyzed the characteristics of road signs and have investigated current erasing methods in the field. And we have organized and designed automatic erasing equipment, and we have made a basic experiment to find out the optimal spray condition as like the spray distance, spray angle and injection pressure.

• Nuclear Engineering and Technology
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• v.26 no.4
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• pp.536-547
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• 1994

The state feedback optimal control techniques are used in designing the reactor control system. The mathematical plant model with the temperature feedback effects is established from the one delayed neutron group point kinetics equation and the singly lumped thermal-hydraulic balance equations, and is expressed in terms of state variables. The LQR (Linear Quadratic Regulator) control system is designed, being followed by the LQG (Linear Quadratic Gaussian) design to determine the optimal conditions of rod movement for the desired reactor power responses. And two different servo control schemes, the ordinary feedback system and the order increased regulating system, are proposed for the purpose of input tacking. The general control characteristics such as stability margins and output responses are discussed. Comparing each other, it is found that the order increased regulating system has far better control characteristics than the ordinary feedback system.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.2
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• pp.357-364
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• 2001

This study deals with the effect on non-martensitic layer on the fatigue strength in carburized gear. The test gears are carburized, then treated by the combination of chemical polishing and electro-polishing. Carburization treatment is used widely on parts of power transmission system like surface hardened layer to improve fatigue strength. Carburized gears are observed using a scanning electron microscope(SEM) to determine the characteristics of crack initiation mechanism in the surface layer. The constant street amplitude fatigue test is performed by using and electro-hydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. The effect of non-martensitic layer on the fatigue strength is clarified.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.80-84
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• 2001

When the fuzzy controller apply to a real plant, We have not excepted result of a satisfactory control by modeling error and lacking information about an plant. In this case, we have to adjust the control factors for improvement of the control performance and this method need a lot of time and cost for perform a trial and error. In this paper, we proposed the fuzzy regulator with the automatic adjustment of scaling factors. It was improve upon the control performance using a adequate scale factor by fuzzy inference. We implemented the controller using the DSP processor and applied in a hydraulic servo system. And then we observed an experimental results.

• Transactions of Materials Processing
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• v.14 no.9 s.81
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• pp.764-771
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• 2005

This study is related with the development of CNC spinning machine and the axisymmetric conventional spinning such as drum type and conical type steel shells. The CNC spinning machine is constructed with heavy duty frame and the hydraulic servo system is applied in order to give the exactness of motion control. The experiment has been carried out considering feeding velocity, mandrel shape, and the corner radius of mandrel and forming rollers. As a result of experiment, the limiting spinning ratio and thickness strain distribution are obtained and it can be seen that the spinnability is dominant to the feeding velocity and corner radius of forming roller. This research can contribute to the development of axisymmetric mechanical part which is applicable to automotive and aerospace industry.