• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.15-21
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• 1997

In this paper, a self-activated cable spooling system for seaborne winch is developed . The system consists of a hydraulic servo driving unit and a cable position measurement mechanism. To realize the cable spooling system, it is carried out the mathematical modelling of the system and designed the proportional controller through the system aalysis and the simulation. The cable spooling system is tested and evaluated to validate the performance of the controller. The test results shows a good traceability of the cable spooling system under disturbance of cable tension.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.738-750
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• 1994

The load-sensing hydraulic system which was developed to improve energy efficiency of conventional hydraulic systems has its own properties. The instability of system responses, linearity of a servo valve, robustness for variation of external load, and dynamic interference between hydraulic motors are such properties which have much to do with control properties of the system. The load-sensing hydraulic system has instability tendancy because the load-sensing mechanism makes a positive feedback loop between the motor part and the pump part. A flow property of the servo valve can be said to be linear because the flow through the valve has nothing to do with a load pressure and the flow is strictly proportional to a valve opening which is adjusted by a valve command signal. The resultant control property can be said to be robust because the steady-state control performance is independent to the load actuated on the motor shaft. In the case when one pump simultaneously drives more than two hydraulic motors, the pump outlet pressure is determined by a hydraulic motor of the largest load pressure among all of the hydraulic motors, and, thus, the other motors are dominated by the largest load pressure. That is, the other motors can be said to be interfered by the motor of the largest load pressure.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.342-347
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• 2003

In this paper, an active vibration control of a translating tensioned string with the use of an electro-hydraulic servo mechanism at the right boundary is investigated. The dynamics of the moving strip is modeled as a string with tension by using Hamilton’s principle for the systems with changing mass. The control objective is to suppress the transverse vibrations of the strip via boundary control. A right boundary control law in the form of current input to the servo valve based upon the Lyapunov’s second method is derived. It is revealed that a time-varying boundary force and a suitable passive damping at the right boundary can successfully suppress the transverse vibrations. The exponential stability of the closed loop system is proved. The effectiveness of the control laws proposed is demonstrated via simulations.

• Tribology and Lubricants
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• v.30 no.6
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• pp.370-377
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• 2014

The basic elements in a rotary-type scroll compressor are two identical spiral scrolls containing refrigerant gas. The pressure variations in the compression pockets of a scroll compressor change the forces acting on the orbiting scroll, and these forces affect the dynamic behavior of the compression mechanism parts. To achieve high efficiency, using a self-sealing mechanism as a tip seal mechanism is very effective. Tip seals, which are placed on top of the scroll wraps, accomplish thrust sealing. This study calculates the friction force between the tip seal and the side plate of a scroll compressor using the numerical model considered in the Reynolds equation. The calculated friction force is verified by an experiment using a pin-on-disk apparatus. A hydraulic servo valve that controls the pressure of the oil hydraulic cylinder applies the normal load for the test, and a DC servo motor controls the sliding velocity of the disk. The friction force and normal load are measured by the force sensors attached to the supporting parts. The results show that the theoretical and experimental results are similar and that the friction is influenced by the viscosity of the oil and the sliding velocity of the scroll.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.137-137
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• 2000

In this research. we developed Tire Roller Prototype which is operated hydraulic transmission system. For develop the theoretically computer aided system, we practiced the simulation of hydraulic system and dynamic modeling and will compare with the experiment results of Tire Roller Prototype. We conceptualize the new hydraulic system and derive the equations of motion for dynamic analysis. Finally, we will design the controller, which can manage the hydraulic circuit of servo mechanism system. We define new hydraulic system and integrate modeling of Tire Roller through simulation of h\ulcornerdraulic system and design of controller. From above procedure. Hydraulic transmission system characteristics and target performance can be investigated. To follow the required performance, we select the parts of Tire Roller. We manufactured the prototype of Tire Roller, and will install the equipment for experiment.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.346-351
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• 1987

In this study, digital simulation with nonlinear modeling is carried out to analyse the performance of a hydraulic servomotor system developed for the position control of a large inertia. Nonlinear element, such as nonlinear pressure flow relationships of servovalve, valve spool limits, nonlinear friction, and backlash and resilience of gear system are included in the simulation along with the dynamic characteristics of variable delivery pump compensation mechanism. Simulation results are compared with experimental results for both step and sinusoidal inputs. Independent of input magnitude, both results are in good agreement with minor differences in detail.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.52-61
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• 2001

The purpose of this paper is to study on the control of a self-activated cable spooling system for towed away handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specfications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.250-250
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• 2000

The purpose of this paper is to study on the control of a self-activated cable spooling system for towed array handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specifications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1062-1070
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• 1995

The study deals with controlling the velocity of hydraulic motor with PI controller through the control of displacement pump which has higher efficiency than valve-controlled system. This was done as follows. First, we modified original displacement pump and designed this electrohydraulic puma system. Second, after experimenting static and dynamic characteristics, we identified system parameter of approximated model. Lastly, to control the velocity of hydraulic motor we controlled the angle of the swash plate of displacement pump. Test carried out in the laboratory shows that transient and steady state response could be improved by PI controller reducing power loss.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1445-1449
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• 1996

To evaluate of active suspension, it is necessary for special equipment - so called Test Rig which can perfectly realize the road condition and the impact from the road. And most of the test rig systems controlling force accurately and rapidly consist of electro-hydraulic servo mechanism, and they need robust controller which can endure outer road change. But in the case of PID controller, we should choose its best gains by trial and error method, and once its gains are fixed, they cannot get changed, so we should reset PID controller gains respectively when the road is changed. Therefore based on the load pressure feedback compensation method, our aim at constructing electro-hydraulic test rig is not affected by various road disturbance.