scholarly journals A DESIGN TECHNIQUE OF HYDRAULIC SERVO ACTUATOR SYSTEMS FOR EFFECTIVE POWER TRANSMISSION

1999 ◽  
Vol 1999 (4) ◽  
pp. 279-284
Author(s):  
Takao NISHIUMI ◽  
Shizurou KONAMI
Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6464
Author(s):  
Wensen Zhang ◽  
Jian Fu ◽  
Yongling Fu ◽  
Jinlin Zhou ◽  
Xudong Han

With the development of more/all electric aircraft, replacement of the traditional hydraulic servo actuator (HSA) with an electromechanical actuator (EMA) is becoming increasingly attractive in the aerospace field. This paper takes an EMA for a trimmable horizontal stabilizer as an example and focuses on how to establish a system model with an appropriate level of complexity to support the model-based system engineering (MBSE) approach. To distinguish the nonlinear effects that dominate the required system performance, an incremental approach is proposed to progressively introduce individual nonlinear effects into models with different complexity levels. Considering the special design and working principle of the mechanical power transmission function for this actuator, the nonlinear dynamics, including friction and backlash from the no-back mechanism, and the nonlinear compliance effect from the mechanical load path are mainly taken into consideration. The modelling principles for each effect are addressed in detail and the parameter identification method is utilized to model these nonlinear effects realistically. Finally, the responses from each model and experimental results are compared to analyze and verify how each individual nonlinearity affects the system’s performance.


2021 ◽  
Vol 1172 (1) ◽  
pp. 012037
Author(s):  
E E Ibrahim ◽  
T Elnady ◽  
I Saleh ◽  
S Hassan

2018 ◽  
Author(s):  
Jinwei Chen ◽  
Jingxuan Li ◽  
Shengnan Sun ◽  
Huisheng Zhang

Fuel supply system, the regulation system for fuel delivery to the combustor, is one of the most important auxiliary systems in a gas turbine engine. Commonly, the fuel supply system was always simplified as a linear system. In fact, gas turbine engines almost use a hydromechanical main fuel control system which consists of electro-hydraulic servo actuator and fuel metering unit. These components have several nonlinear characteristics such as hysteresis, dead zone, relay, and saturator. These nonlinear characteristics can directly affect the performance a gas turbine engine. In this paper, a three-shaft gas turbine engine was taken as a research object. Firstly, a mechanism model of the fuel control system considering the nonlinear links was developed based on the hydro-mechanical theory. Then, the effect of dead zone-relay characteristic of the servo amplifier in electro-hydraulic servo actuator was analyzed. The results show that the dead zone width has great effect on the dynamic performance of the gas turbine engine. The fuel flow rate will be oscillating with small dead zone width. The parameters of the gas turbine engine will be stable with the increase of dead zone width. However, the larger dead zone width causes the hysteresis and the increase of the dynamic response time. At the same time, an improvement method with a two-dimensional fuzzy compensation was proposed. The results show that the fuzzy compensation can effectively solve the oscillation problem caused by the dead zone-delay. Finally, a Hardware-In-the-Loop (HIL) system is developed which is based on an electro-hydraulic servo actuator facility and a real-time software component of the gas turbine engine. An experiment is conducted on the HIL test rig to validate simulation result. The results show that the experiment matches well with the simulation results.


Author(s):  
Antonio C. Bertolino ◽  
Rocco Gentile ◽  
Giovanni Jacazio ◽  
Francesco Marino ◽  
Massimo Sorli

Seals are widely used in hydraulic power systems to prevent fluid leakages. However, several types of degradation can decrease the performance of these components such as wear, which induces changes in the geometry of the cross-section area, influencing their sealing capability. Over the years, their behaviour has been primarily investigated with several theoretical and experimental researches. All these valuable results can be considered as a starting point for further investigations on the interaction between seals and the complete hydraulic equipment and on the root of seals degradation. This article proposes a physical model of performance degradation acting on dynamic seals of an electro-hydraulic servo-actuator (EHSA) ram for primary flight controls. In this article, a dynamic non-linear seals degradation model has been developed, based on the Hart-Smith hyperelasticity model, which physically describes the stress and strain of “rubber-like” materials. Similarly, wearing has been assessment by using the Archard’s equation. Furthermore, different operating temperatures have been considered to analyze the effect on seals performances. The integration between the mentioned seals degradation model and the high-fidelity model of the complete EHSA allows to evaluate the influence of various wear levels on the actuator behaviour. This research activity is inserted into a more extensive project of Prognostic and Health Management (PHM) of EHSAs. The results of the proposed simulations reveal how the performance of an EHSA can be affected by seals degradations.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhenshuai Wan ◽  
Yu Fu

Hydraulic servo actuator always suffers from various disturbance and uncertainties, which makes it difficult to design a higher performance controller. In this paper, an integral nonsingular terminal sliding mode controller based on extended state observer (ESO-INTSM) is proposed to improve the robust performance of hydraulic servo actuator. The ESO is designed to estimate not only the parametric uncertainties but also the model disturbance. Based on the observed states of ESO, the proposed controllers could enable hydraulic servo actuator to track the desired motion trajectories. The stability of the synthesized controller is proved via Lyapunov analysis, which is very important for high-accuracy tracking control of hydraulic servo actuator. Simulation and experimental results demonstrate that the proposed control strategy can effectively attenuate the adverse influence caused by the uncertainties and apparently improve the tracking accuracy.


2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Junho Hong ◽  
Dahie Hong ◽  
Byung Gon Kim

Abstract Tendon sheath mechanism (TSM) is an effective power transmission system to access remote locations through tortuous channels, and it is widely used in endoscopic surgical robots. However, owing to deformation of TSM during power transmission, the input–output hysteresis is expressed in the form of backlash-like hysteresis. This paper is premised on the idea that sheath deformation can occur if the sheath is fixed only at certain points rather than being fully fixed at all points. Based on our hypothesis, a new TSM-pair backlash-like hysteresis model was derived, which considers the deformation property of the sheath. Experimental setups were designed to validate the new model, and its mechanical parameters were identified. The experimental results revealed that the sheath significantly deforms and that such deformation produces backlash-like hysteresis together with the tendon deformation. This model can be used to provide accurate prediction and control of TSM.


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