Modeling &amp; Simulation of a Hydraulic Servo Actuator Cushion for Power Plants

Lee, Yong Bum; Yoon, Young Hwan

doi:10.9725/kstle-2013.29.1.007

Cited by 5 publications

(3 citation statements)

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“…analysis technology, when used with an existing compatible design program, facilitates modeling and analysis of complicated machine systems [5][6][7][8][9]. This technology works by dividing the components of the machine system into body, joint, and force elements, and by applying the mechanical and dynamic constraints distinctive to each component to organize the system equation of motion.…”

Section: Heave Compensation System Oil Pressure Modelingmentioning

confidence: 99%

“…This is done by determining the behaviors of parts resulting from the load or deformation, not inside a part, but generated by its movement and transferred to other parts, and by assessing interference between parts. Compared with previous manual parametric modeling, multi-body dynamics analysis technology, when used with an existing compatible design program, facilitates modeling and analysis of complicated machine systems [5][6][7][8][9]. This technology works by dividing the components of the machine system into body, joint, and force elements, and by applying the mechanical and dynamic constraints distinctive to each component to organize the system equation of motion.…”

Section: Introductionmentioning

confidence: 99%

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Method for Analysis of an Offshore Heave Compensator

Kim

Hwang

Hyeon³

et al. 2016

Applied Sciences

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A heave compensation system consists of a drill string compensator (DSC) and an active heave compensator (AHC) cylinder, which together produce control force over an oil pressure system suitable for transmission of considerable power and compensating for heaving motion of the hull during drilling work. In this study, a heave compensator of an oil pressure system was simulated to draw a conclusion, which was verified by comparison with the result of a test conducted using an actual miniature model. The compensation rate was 95%, based on which the dynamic behaviors of an actual-size heave compensator were presumed. Furthermore, the speed of each cylinder and the acceleration of heave can be determined and used to fabricate an actual-size heave compensator.

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Section: Heave Compensation System Oil Pressure Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Method for Analysis of an Offshore Heave Compensator

Kim

Hwang

Hyeon³

et al. 2016

Applied Sciences

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“…Lee et al (13) añaden un mecanismo de amortiguación a un servo actuador hidráulico, que es el elemento de control de la potencia de una turbina en una planta de generación de energía. El diseño incorpora los elementos propios del circuito hidráulico que permite operar con gran rapidez el actuador en caso de ser necesaria la parada de emergencia de la turbina.…”

Section: Simulación Dinámica De La Arquitectura Del Circuito Hidráuli...unclassified

Amortiguación de final de carrera de actuadores hidráulicos

Algar Espejo

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The internal cushioning systems of hydraulic linear actuators, of special interest in mobile machinery, pursue to avoid mechanical shocks at their end of stroke. The design where the piston, with perimeter grooves, regulates the flow by standing in front of the outlet port has not been studied in depth until now. Consequently, the operating fundamentals, influencing factors and optimization of these cushioning designs have been investigated. First, a dynamic model has been developed using the bond graph technique that integrates the mechanical equations of the actuator, the hydraulic circuit and the flow through the studied internal cushion design. This considers the evolution of internal flow during cushioning, characterized in detail by fluid-dynamic simulation. This CFD model has been validated experimentally for its refinement and well-founded determination of discharge coefficients. Subsequently, the complete dynamics of the actuator and, in particular, the radial movement of the piston are experimentally studied by means of the difficult installation of a sophisticated displacement sensor. Finally, the experimental observations and the fluid-dynamic coefficients are integrated into the dynamic model; ultimately, the model aims to predict the experimental behavior of the cushioning during the movement of the arm of an excavator. The radial movement of the observed piston turns it into an active and adjusting element that is essential in cushioning. This radial movement in coherence with the significant drag force estimated in the CFD simulation, generated by the flow through the grooves, where the laminar flow regime predominates. Analytical models are suitable for predicting the behavior of the cushioning system, observing results comparable to those experimentally obtained . There is an optimal behavior, highly influenced by the mechanical stress conditions of the system, subject to a compromise between an increasing section of the grooves and an optimization of the radial gap. In addition, given the difficult direct measurement of the radial movement of the piston, an indirect measurement method has been evaluated using low-cost accelerometers. Thus, a bond graph simulation model predicts the results of the double integration of acceleration, observed experimentally. Influenced by the diverse nature of the existing movements, the severe propagation of measurement errors makes indirect measurement of piston radial motion inadequate. Los sistemas internos de amortiguación de actuadores lineales hidráulicos, de especial interés en maquinaria móvil, buscan evitar choques mecánicos en sus finales de carrera. El diseño donde el pistón, dispuesto con ranuras perimetrales, regula el flujo al interponerse frente al puerto de salida no ha sido estudiado en profundidad hasta ahora. En consecuencia, se han investigado las bases de funcionamiento, los factores de influencia y la optimización de estos diseños de amortiguación. Primeramente, se ha desarrollado un modelo dinámico mediante la técnica bond graph que integra las ecuaciones mecánicas propias del actuador, del circuito hidráulico y del flujo a través del amortiguador interno estudiado. Éste considera la evolución del flujo interno durante la amortiguación, caracterizada detalladamente mediante simulación fluido-dinámica. Este modelo CFD ha sido validado experimentalmente para su refinamiento y la determinación fundada de los coeficientes de descarga. Seguidamente, se estudia experimentalmente la dinámica completa del actuador y, en especial, el movimiento radial del pistón mediante la difícil instalación de un sofisticado sensor de desplazamiento. Finalmente, las observaciones experimentales y los coeficientes fluido-dinámicos se integran en el modelo dinámico; éste pretende, en última instancia, prever el comportamiento experimental de la amortiguación del actuador durante el movimiento del brazo de una retroexcavadora. El movimiento radial del pistón observado convierte éste en un elemento activo fundamental en la amortiguación. Este movimiento radial es coherente con la significativa fuerza de empuje estimada en la simulación CFD, generada por el flujo a través de las ranuras, donde predomina el régimen laminar. Los modelos analíticos se muestran adecuados para la predicción del comportamiento del sistema de amortiguación, observándose resultados comparables a los obtenidos experimentalmente. Existe un comportamiento óptimo, influenciado en gran medida por las condiciones de solicitación mecánica del sistema, sujeto a un compromiso entre una sección creciente de las ranuras y una optimización del espacio radial. Complementariamente, dada la complicada medida directa del movimiento radial del pistón, se ha evaluado la medida indirecta mediante acelerómetros de bajo coste. Así, un modelo de simulación bond graph predice los resultados de la doble integración de la aceleración, observados experimentalmente. Influenciada por la diversa naturaleza de los movimientos presentes, la severa propagación de los errores de medida hace inadecuada la medida indirecta del movimiento radial del pistón.

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A Study on Failure Analysis and High Performance of Hydraulic Servo Actuator

2020

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Hydraulic servo actuator is used as the core actuator in tensile compression fatigue life test equipment as it operates the micro displacement very precisely at a high frequency and can be used continuously for a long period of time. Recently, the life expectancy of automobiles has been extended, the load conditions of accelerated life testing on auto parts have been increased, and the life test time and number of tests have increased significantly in order to secure the reliability of the guaranteed life of produced vehicles. Therefore, hydraulic servo actuators mounted on accelerated life testing equipment for automotive parts are essential for much higher performance and a longer life than those tested. However, small- and medium-sized companies that supply test equipment for the fatigue life of auto often fail to develop technology due to a lack of research personnel and the development budget compared to the capabilities of large automobile manufacturers, resulting in frequent breakdowns due to the technical overload of test equipment. In this study, servo actuators were used to test automotive parts, with a maximum output of 2 ton, a maximum frequency of 3.3 Hz and a maximum displacement of 50 mm. The hydraulic servo actuator, which was installed in the tensile compression fatigue life test equipment, failed to operate normally at the site, and by analyzing it, we realized this resulted from the heat generation of insulation compression due to the accumulation of air and gas into the hydraulic oil and the increase in friction due to the deterioration of flow. A static pressure bearing was adopted as a design change to improve the root cause for this failure mode, and a very high level of geometric concentricity was secured by inserting concentric tubes outside the labyrinth seal type piston. The newly designed and manufactured actuator is the result of research that has achieved a semi-permanent long life and improved performance up to 100 Hz by non-contact operation.

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Modeling & Simulation of a Hydraulic Servo Actuator Cushion for Power Plants

Cited by 5 publications

References 0 publications

Method for Analysis of an Offshore Heave Compensator

Method for Analysis of an Offshore Heave Compensator

Amortiguación de final de carrera de actuadores hidráulicos

A Study on Failure Analysis and High Performance of Hydraulic Servo Actuator

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