High Fidelity Model of a Ball Screw Drive for a Flight Control Servoactuator

2017 ◽  
Author(s):  
Antonio C. Bertolino ◽  
Giovanni Jacazio ◽  
Stefano Mauro ◽  
Massimo Sorli
Keyword(s):  
Sensitivity Analysis ◽  
Flight Control ◽  
Contact Stiffness ◽  
Rolling Friction ◽  
Operating Conditions ◽  
Ball Screw ◽  
High Fidelity ◽  
Health State ◽  
Electric Equipment ◽  
Fidelity Model

Over the past years, a trend toward “more electric” equipment has arisen including flight control systems, leading to a tendency to replace the electro-hydraulic actuators (EHSAs) with electro-mechanical actuators (EMAs), which have however a too high jamming probability for a primary flight control system. An innovative jam tolerant approach is to make the EMA “jam-predictive” by monitoring its health state using effective prognostic algorithms. The need for a high-fidelity model is then paramount. In this study, basing on a typical architecture of an EMA, a detailed analysis of the developed dynamic non-linear ball screw model is presented. The backlash, friction parameters, a model of the rolling/sliding behaviour of a ball with rolling friction are taken into account, contact stiffness and preload are introduced. A discussion is presented on the results of a sensitivity analysis on the efficiency of the mechanism with respect to the above mentioned characteristic parameters under different operating conditions. The model and the results of the sensitivity analysis can be used to better understand the physics within the actuator and the ensuing fault-to-failure mechanisms which are needed for developing more efficient prognostic algorithms.

High-Fidelity Model of Electro-Hydraulic Actuators for Primary Flight Control Systems

2018 ◽  
Author(s):  
Andrea De Martin ◽  
Andrea Dellacasa ◽  
Giovanni Jacazio ◽  
Massimo Sorli
Keyword(s):  
Control System ◽  
Control Systems ◽  
Flight Control ◽  
Weather Condition ◽  
High Fidelity ◽  
Flight Control System ◽  
Hydraulic Actuators ◽  
Wide Range ◽  
Definition Of ◽  
Fidelity Model

Hydraulic actuators are the de facto standard for primary flight control systems, since they provide low jamming probability and intrinsic damping capabilities. Electro-Hydraulic Actuators theoretically provide a number of advantages over the traditional hydraulic systems, such as the decrease in the overall power consumption, easier installation and reduced weight of the flight control system, but are so far mostly used as back-up solutions in civil applications. Flight control actuators can face an extremely wide range of operational scenarios depending on the aircraft route, weather condition, pilot behavior and components health. The use of high-fidelity models is instrumental in the design of both actuators and control laws and can enhance the definition of a Prognostics and Health Monitoring system, given its capability to simulate a huge number of possible in-flight situations. In this paper, we provide the mathematical definition of a novel high-fidelity model for primary flight control system, discuss its implementation and results in nominal and off-nominal conditions.

Robust Design of a Test Bench for PHM Study of Ball Screw Drives

2019 ◽  
Author(s):  
A. C. Bertolino ◽  
A. De Martin ◽  
G. Jacazio ◽  
S. Mauro ◽  
M. Sorli
Keyword(s):  
Flight Control ◽  
Test Bench ◽  
Test Procedure ◽  
Ball Screw ◽  
Process Noise ◽  
Safety Issues ◽  
Research Themes ◽  
Definition Of ◽  
Ball Screw Drives ◽  
Fidelity Model

Abstract Over the last two decades, one of the most prominent research themes in the aerospace community involved the definition of “more electric aircrafts”. For flight control systems the trend is to replace the traditional electro-hydraulic solution with electro-mechanical actuators. However, safety issues severely hinder the diffusion of this technology. A possible breakthrough in this field can be the development of robust PHM techniques to anticipate the occurrence of failures. Ball screws feature one of the highest failure rate within EMAs’ mechanical components. Since their accurate modeling is fairly complex, experimental results are needed to support simulation outcomes to help in the definition of reliable health monitoring schemes. This paper presents the model-based design of a novel test bench intended for PHM analyses of ball screw drives. At first the test bench layout is introduced and compared to the state of the art. A high-fidelity model of the test bench is presented and exploited to perform a Monte Carlo simulation campaign with the goal to characterize its behavior versus measure and process noise in presence of varying size backlash. Finally, a test procedure for backlash identification is defined.

Control Variate Multifidelity Estimators for the Variance and Sensitivity Analysis of Mesostructure–Structure Systems

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Hongyi Xu ◽  
Zhao Liu
Keyword(s):  
Sensitivity Analysis ◽  
System Analysis ◽  
Computational Cost ◽  
High Fidelity ◽  
Structure System ◽  
Control Variate ◽  
Pros And Cons ◽  
New Formulation ◽  
The Comparative Study ◽  
Fidelity Model

Variance and sensitivity analysis are challenging tasks when the evaluation of system performances incurs a high-computational cost. To resolve this issue, this paper investigates several multifidelity statistical estimators for the responses of complex systems, especially the mesostructure–structure system manufactured by additive manufacturing. First, this paper reviews an established control variate multifidelity estimator, which leverages the output of an inexpensive, low-fidelity model and the correlation between the high-fidelity model and the low-fidelity model to predict the statistics of the system responses. Second, we investigate several variants of the original estimator and propose a new formulation of the control variate estimator. All these estimators and the associated sensitivity analysis approaches are compared on two engineering examples of mesostructure–structure system analysis. A multifidelity metamodel-based sensitivity analysis approach is also included in the comparative study. The proposed estimator demonstrates its strength in predicting variance when only a limited number of expensive high-fidelity data are available. Finally, the pros and cons of each estimator are discussed, and recommendations are made on the selection of multifidelity estimators for variance and sensitivity analysis.

scholarly journals Sensitivity Analysis of OTEC-CC-MX-1 kWe Plant Prototype

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2585
Author(s):  
Jessica Guadalupe Tobal-Cupul ◽  
Estela Cerezo-Acevedo ◽  
Yair Yosias Arriola-Gil ◽  
Hector Fernando Gomez-Garcia ◽  
Victor Manuel Romero-Medina
Keyword(s):  
Sensitivity Analysis ◽  
Experimental Tests ◽  
Caribbean Sea ◽  
Ocean Model ◽  
Operating Conditions ◽  
Working Fluid ◽  
Ocean Energy ◽  
Mexican Caribbean ◽  
Water Temperature Data ◽  
Mass Flows

The Mexican Caribbean Sea has potential zones for Ocean Thermal Energy Conversion (OTEC) implementation. Universidad del Caribe and Instituto de Ciencias del Mar y Limnologia, with the support of the Mexican Centre of Innovation in Ocean Energy, designed and constructed a prototype OTEC plant (OTEC-CC-MX-1 kWe), which is the first initiative in Mexico for exploitation of this type of renewable energy. This paper presents a sensitivity analysis whose objective was to know, before carrying out the experimental tests, the behavior of OTEC-CC-MX-1 kWe regarding temperature differences, as well as the non-possible operating conditions, which allows us to assess possible modifications in the prototype installation. An algorithm was developed to obtain the inlet and outlet temperatures of the water and working fluid in the heat exchangers using the monthly surface and deep-water temperature data from the Hybrid Coordinate Ocean Model and Geographically Weighted Regression Temperature Model for the Mexican Caribbean Sea. With these temperatures, the following were analyzed: fluctuation of thermal efficiency, mass flows of R-152a and water and power production. By analyzing the results, we verified maximum and minimum mass flows of water and R-152a to produce 1 kWe during a typical year in the Mexican Caribbean Sea and the conditions when the production of electricity is not possible for OTEC-CC-MX-1 kWe.

The analysis on the influence of mixed sliding-rolling motion mode to precision degradation of ball screw

2021 ◽  
pp. 095440622098201
Author(s):  
Qiang Cheng ◽  
Baobao Qi ◽  
Hongyan Chu ◽  
Ziling Zhang ◽  
Zhifeng Liu ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Ball Screw ◽  
Rolling Motion ◽  
Degradation Model ◽  
Sliding Motion ◽  
Factors Analysis ◽  
Motion Mode

The combination of sliding/rolling motion can influence the degree of precision degradation of ball screw. Precision degradation modeling and factors analysis can reveal the evolution law of ball screw precision. This paper presents a precision degradation model for factors analysis influencing precision due to mixed sliding-rolling motion. The precision loss model was verified through the comparison of theoretical models and experimental tests. The precision degradation due to rolling motion between the ball and raceway accounted for 29.09% of the screw precision loss due to sliding motion. Additionally, the total precision degradation due to rolling motion accounted for 21.03% of the total sliding precision loss of the screw and nut, and 17.38% of the overall ball screw precision loss under mixed sliding-rolling motion. In addition, the effects of operating conditions and structural parameters on precision loss were analyzed. The sensitivity coefficients of factors influencing were used to quantitatively describe impact degree on precision degradation.

Adaptive response prediction for aerodynamic shape optimization

2017 ◽  
Vol 34 (5) ◽  
pp. 1485-1500
Author(s):  
Leifur Leifsson ◽  
Slawomir Koziel
Keyword(s):  
Shape Optimization ◽  
Adaptive Response ◽  
Simulation Models ◽  
Response Prediction ◽  
High Fidelity ◽  
High Fidelity Simulation ◽  
Aerodynamic Shape Optimization ◽  
Content Type ◽  
Aerodynamic Shape ◽  
Fidelity Model

Purpose The purpose of this paper is to reduce the overall computational time of aerodynamic shape optimization that involves accurate high-fidelity simulation models. Design/methodology/approach The proposed approach is based on the surrogate-based optimization paradigm. In particular, multi-fidelity surrogate models are used in the optimization process in place of the computationally expensive high-fidelity model. The multi-fidelity surrogate is constructed using physics-based low-fidelity models and a proper correction. This work introduces a novel correction methodology – referred to as the adaptive response prediction (ARP). The ARP technique corrects the low-fidelity model response, represented by the airfoil pressure distribution, through suitable horizontal and vertical adjustments. Findings Numerical investigations show the feasibility of solving real-world problems involving optimization of transonic airfoil shapes and accurate computational fluid dynamics simulation models of such surfaces. The results show that the proposed approach outperforms traditional surrogate-based approaches. Originality/value The proposed aerodynamic design optimization algorithm is novel and holistic. In particular, the ARP correction technique is original. The algorithm is useful for fast design of aerodynamic surfaces using high-fidelity simulation data in moderately sized search spaces, which is challenging using conventional methods because of excessive computational costs.

Fully Parametric High-Fidelity CFD Model for the Design Optimisation of the Cyclic Stagger Pattern of a Set of Fan Outlet Guide Vanes

2009 ◽  
Author(s):  
Andrea Milli ◽  
Olivier Bron
Keyword(s):  
Complex Geometry ◽  
Single Point ◽  
Sensitivity Study ◽  
Operating Conditions ◽  
High Fidelity ◽  
Cfd Model ◽  
Design Optimisation ◽  
Guide Vanes ◽  
High Loss ◽  
Design Variables

The present paper deals with the redesign of cyclic variation of a set of fan outlet guide vanes by means of high-fidelity full-annulus CFD. The necessity for the aerodynamic redesign originated from a change to the original project requirement, when the customer requested an increase in specific thrust above the original engine specification. The main objectives of this paper are: 1) make use of 3D CFD simulations to accurately model the flow field and identify high-loss regions; 2) elaborate an effective optimisation strategy using engineering judgement in order to define realistic objectives, constraints and design variables; 3) emphasise the importance of parametric geometry modelling and meshing for automatic design optimisation of complex turbomachinery configurations; 4) illustrate that the combination of advanced optimisation algorithms and aerodynamic expertise can lead to successful optimisations of complex turbomachinery components within practical time and costs constrains. The current design optimisation exercise was carried out using an in-house set of software tools to mesh, resolve, analyse and optimise turbomachinery components by means of Reynolds-averaged Navier-Stokes simulations. The original configuration was analysed using the 3D CFD model and thereafter assessed against experimental data and flow visualisations. The main objective of this phase was to acquire a deep insight of the aerodynamics and the loss mechanisms. This was important to appropriately limit the design scope and to drive the optimisation in the desirable direction with a limited number of design variables. A mesh sensitivity study was performed in order to minimise computational costs. Partially converged CFD solutions with restart and response surface models were used to speed up the optimisation loop. Finally, the single-point optimised circumferential stagger pattern was manually adjusted to increase the robustness of the design at other flight operating conditions. Overall, the optimisation resulted in a major loss reduction and increased operating range. Most important, it provided the project with an alternative and improved design within the time schedule requested and demonstrated that CFD tools can be used effectively not only for the analysis but also to provide new design solutions as a matter of routine even for very complex geometry configurations.

Fractal Analysis for Vibrational Signals Created in a Ball-Screw Machine Operating in Short- and Long-Range Tribological Tests

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Min-Chi Chang ◽  
Jeng Luen Liou ◽  
Chin-Chung Wei ◽  
Jeng-Haur Horng ◽  
Yueh-Ling Chiu ◽  
...  
Keyword(s):  
Long Range ◽  
Fractal Analysis ◽  
Rotational Speed ◽  
Operating Conditions ◽  
Ball Screw ◽  
Frictional Torque ◽  
A Value ◽  
Vibrational Signals ◽  
Inner Surface ◽  
Range Test

In the present study, the vibrational and frictional torque signals acquired from the forward-backward movements of a commercial ball-screw system were considered via mono fractal analysis. The short-range tests were carried out in order to investigate the effects of operating conditions, a nut's inner surface roughness and the applied pretension (preload) on the fractal dimension (Ds) and topothesy (G). The long-range test was conducted to observe the variations of vibrational and frictional torque signals and thus the fractal parameters acquired from the ball-screw operations under the condition of no fresh grease supply during the testing process. The effects of the ball-screw rotational speed and pretension on the G parameter of vibrations were greater than the Ds parameter. In the backward movement, the highest G value always occurred at the highest rotational speed (3000 rpm in this study). The Ds parameter generated in the forward movement by the nut's inner surface before polishing produced a value greater than that by the nut with a polished surface. The G parameter related to vibrational amplitudes showed a value before polishing greater than that after polishing. The unusual vibrational signals are assumed to be related to ball passing behavior. Their experimental frequency was verified to be consistent with the frequency predicted by the ball pass theory. An increase in the rotational speed can bring a significant increase in the number of ball-pass signals. The G parameter and its skewness data, defined for the number distribution function of the G peaks, showed values that in general increased with the test time if the fresh grease was not supplied during the long-range test.

Efficiency and Sensitivity Analysis of Cavern-Based CAES Systems During off-Design Operating Conditions

2021 ◽  
pp. 177-199
Author(s):  
Mehdi Ebrahimi ◽  
David S.-K. Ting ◽  
Rupp Carriveau ◽  
Andrew McGillis ◽  
David Brown
Keyword(s):  
Sensitivity Analysis ◽  
Operating Conditions

scholarly journals High Fidelity Microsurgical Simulation: The Thiel Model and Evaluation Instrument

2018 ◽  
Vol 27 (2) ◽  
pp. 118-124 ◽  
Author(s):  
Andrei Odobescu ◽  
Isak Goodwin ◽  
Djamal Berbiche ◽  
Joseph BouMerhi ◽  
Patrick G. Harris ◽  
...  
Keyword(s):  
External Validity ◽  
Internal Validity ◽  
High Fidelity ◽  
Evaluation Instrument ◽  
Intra Class Correlation ◽  
Validity Measures ◽  
The Difference ◽  
Fidelity Model ◽  
Junior Residents ◽  
Internal And External Validity

Background: The Thiel embalmment method has recently been used in a number of medical simulation fields. The authors investigate the use of Thiel vessels as a high fidelity model for microvascular simulation and propose a new checklist-based evaluation instrument for microsurgical training. Methods: Thirteen residents and 2 attending microsurgeons performed video recorded microvascular anastomoses on Thiel embalmed arteries that were evaluated using a new evaluation instrument (Microvascular Evaluation Scale) by 4 fellowship trained microsurgeons. The internal validity was assessed using the Cronbach coefficient. The external validity was verified using regression models. Results: The reliability assessment revealed an excellent intra-class correlation of 0.89. When comparing scores obtained by participants from different levels of training, attending surgeons and senior residents (Post Graduate Year [PGY] 4-5) scored significantly better than junior residents (PGY 1-3). The difference between senior residents and attending surgeons was not significant. When considering microsurgical experience, the differences were significant between the advanced group and the minimal and moderate experience groups. The differences between minimal and moderate experience groups were not significant. Based on the data obtained, a score of 8 would translate into a level of microsurgical competence appropriate for clinical microsurgery. Conclusions: Thiel cadaveric vessels are a high fidelity model for microsurgical simulation. Excellent internal and external validity measures were obtained using the Microvascular Evaluation Scale (MVES).

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