• Journal of Drive and Control
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• v.16 no.1
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• pp.29-35
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• 2019

The control performance of hydraulic systems is basically influenced by the performance of electrohydraulic servo valve incorporated in a hydraulic control system. In this study, a control design was proposed to improve the control performance of a servo valve with a non-contact eddy current type position sensor. A mathematical model for the valve was obtained through an experimental identification process. A PI-D control together with a feedforward (FF) control was applied to the valve. To further improve the dynamic response of the servo valve, an input shaping filter (ISF) was incorporated into the valve control system. Finally, the effectiveness of the proposed control system was verified experimentally.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.399-405
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• 2002

This paper proposes a new type of piezoactuator-driven valve system. The piezoceramic actuator bonded to both sides of a flexible beam surface makes a movement required to control the pressure at the flapper-nozzle of a pneumatic valve system. After establishing a dynamic model, an appropriate size of the valve system is designed and manufactured. Subsequently, a robust H$_{\infty}$ control algorithm is formulated in order to achieve accurate tracking control of the desired pressure. The controller is experimentally realized and control performance for the sinusoidal pressure trajectory is presented in time domain. The control bandwidth of the valve system, which directly represents the fastness, is also evaluated in the frequency domain.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.673-678
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• 2001

This paper proposes a new type of piezoactuator-driven valve system. The piezoceramic actuator bonded to both sides of a flexible beam surface makes a movement required to control the pressure at the flapper-nozzle of a pneumatic valve system. After establishing a dynamic model, an appropriate size of the valve system is designed and manufactured. Subsequently, a robust $H_{\infty}$ control algorithm is formulated in order to achieve accurate tracking control of the desired pressure. The controller is experimentally realized and control performance for the sinusoidal pressure trajectory is presented in time domain. The control bandwidth of the valve system, which directly represents the fastness, is also evaluated in the frequency domain.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.554-558
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• 2000

This paper proposes a new type of piezoactuator-driven valve system. The piezoceramic actuator bonded to both sides of a flexible beam surface makes a movement required to control the pressure at the flapper-nozzle of a pneumatic system. After establishing a dynamic model, an appropriate size of the valve system is designed and manufactured. Subsequently, a sliding mode controller which is known to be robust to uncertainties such as disturbance is formulated in order to achieve accurate regulating and tracking control of the desired pressure. The controller is experimentally realized and control performances for various pressure trajectories are presented in time domain. The control bandwidth of the valve system which directly represents the fastness is also evaluated in the frequency domain.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.2
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• pp.206-213
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• 2001

The positioner is an essential component of the control valve which is used to control quantity of the liquid in the pipe of chemical plants. In this paper, the experimental methodology for current pneumatic positioner was developed for the investigation of the static and dynamic characteristics of the positioner. The methodology was applied to evaluate response characteristics of two different positioners, which are current model in market and newly designed model. The experimental results of these two models were compared and analyzed.

• Journal of Mechanical Science and Technology
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• v.17 no.7
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• pp.978-985
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• 2003

In this paper, a new proportional solenoid invented for pneumatic directional control valves is introduced. The new proportional solenoid has two-dimensional structure and a pivoting armature on which the friction force is inherently negligible. Another advantageous feature of this solenoid is that its mechanical parts can be easily manufactured and assembled. The working principle and design example of the now proportional solenoid, its application to the activation of a 4/3-way directional control valve, and the evaluation of its control performance in a position control loop are reported.

• Structural Engineering and Mechanics
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• v.75 no.3
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• pp.327-337
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• 2020

The stability and dynamic performance of a flapper-nozzle servo valve depend on several factors, such as the motion of the armature component and the deformation of the spring tube. As the only connection between the armature component and the fixed end, the spring tube plays a decisive role in the dynamic response of the entire system. Aiming at predicting the vibration characteristics of the servo valves to combine them with the control algorithm, an innovative dynamic stiffness based on a distributed parameter model (DPM) is proposed that can reflect the dynamic deformation of the spring tube and a suitable discrete method is applied according to the working condition of the spring tube. With the motion equation derived by DPM, which includes the impact of inertia, damping, and stiffness force, the mathematical model of the spring tube dynamic stiffness is established. Subsequently, a suitable program for this model is confirmed that guarantees the simulation accuracy while controlling the time consumption. Ultimately, the transient response of the spring tube is also evaluated by a finite element method (FEM). The agreement between the simulation results of the two methods shows that dynamic stiffness based on DPM is suitable for predicting the transient response of the spring tube.