A simplified model for predicting the propeller-wing interaction

2018 ◽  
Vol 90 (1) ◽  
pp. 196-201
Author(s):  
Xianghua Huang ◽  
Xiaochun Zhao ◽  
Jiaqin Huang

Purpose The traditional numerical methods to predict the interaction between the wing and propeller are too complex and time-consuming for computation to a certain extent. Therefore, they are not applicable for a real-time integrated turboprop aircraft model. This paper aims to present a simplified model capable of high-precision and real-time computing. Design/methodology/approach A wing model based on the lifting line theory coupled with a propeller model based on the strip theory is used to predict the propeller-wing interaction. To meet the requirement of real-time computing, a novel decoupling parameter is presented to replace lifting line model (LLM) applied for wings with a simplified fitting model (FM). Findings The comparison between the LLM and the simplified FM demonstrates that the results of the FM have a good agreement with the results of the LLM, which means that the simplified FM has the advantages of both high-accuracy and real-time computation. Practical implications After simplification, the propeller-wing interaction model is suitable for a real-time integrated turboprop aircraft model. Originality/value A novel decoupling parameter is presented to replace LLM applied for wings with a simplified FM, which has the advantages of both high-accuracy and real-time computation.

2015 ◽  
Vol 32 (2) ◽  
Author(s):  
Jiaqin Huang ◽  
Xianghua Huang ◽  
Tianhong Zhang

AbstractIn the simulation of engine-propeller integrated control system for a turboprop aircraft, a real-time propeller model with high-accuracy is required. A study is conducted to compare the real-time and precision performance of propeller models based on strip theory and lifting surface theory. The emphasis in modeling by strip theory is focused on three points as follows: First, FLUENT is adopted to calculate the lift and drag coefficients of the propeller. Next, a method to calculate the induced velocity which occurs in the ground rig test is presented. Finally, an approximate method is proposed to obtain the downwash angle of the propeller when the conventional algorithm has no solution. An advanced approximation of the velocities induced by helical horseshoe vortices is applied in the model based on lifting surface theory. This approximate method will reduce computing time and remain good accuracy. Comparison between the two modeling techniques shows that the model based on strip theory which owns more advantage on both real-time and high-accuracy can meet the requirement.


2019 ◽  
Vol 91 (7) ◽  
pp. 917-926
Author(s):  
Yiwei Wang ◽  
Xianghua Huang ◽  
Jiaqin Huang

Purpose The purpose of the paper is to build a real-time integrated turboprop take-off model which fully takes the interaction between diverse parts of aircraft into consideration. Turboprops have the advantage of short take-off distance derived from propeller-wing interaction. Traditional turboprop take-off model is inappropriate because interactions between diverse parts of aircrafts are not fully considered or longer calculation time is required. To make full use of the advantage of short take-off distance, a real-time integrated take-off model is needed for analysing flight performance and developing an integrated propeller-engine-aircraft control system. Design/methodology/approach A new integrated three-degree-of-freedom take-off model is developed, which takes a modified propeller model, a wing model and the predominant propeller-wing interaction into account. The propeller model, based on strip theory, overcomes the shortage that the strip theory does not work if the angle of propeller axis and inflow velocity is non-zero. The wing model uses the lifting line method. The proposed propeller-wing interaction model simplifies the complex propeller-wing flow field. Simulations of ATR42 take-off model are conducted in the following three modes: propeller-wing interaction is ignored; influence of propeller on wing is considered only; and propeller-wing interaction is considered. Findings Comparison of take-off distances and flight parameters shows that propeller-wing interaction has a vital impact on take-off distance and flight parameters of turboprops. Practical implications The real-time integrated take-off model provides time-history flight parameters, which plays an important role in an integrated propeller-engine-aircraft control system to analyse and improve flight performance. Originality/value The real-time integrated take-off model is more precise because propeller-wing interaction is considered. Each calculation step costs less than 20 ms, which meets real-time calculation requirements. The modified propeller model overcomes the shortage of strip theory.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shahzad Shabbir ◽  
Muhammad Adnan Ayub ◽  
Farman Ali Khan ◽  
Jeffrey Davis

Purpose Short-term motivation encompasses specific, challenging and attainable goals that develop in the limited timespan. On the other hand, long-term motivation indicates a sort of continuing commitment that is required to complete assigned task. As short-term motivational problems span for a limited period of time, such as a session, therefore, they need to be addressed in real time to keep the learner engaged in the learning process. Similarly, long-term learners’ motivation plays an equally important role to retain the learner in the long run and minimize the risk of dropout. Therefore, the purpose of this study is to incorporate a comprehensive learner motivation model that is based on short-term and long-term aspects of the learners' motivation. This approach enables Web-based educational systems to identify the real-time motivational state of the learner and provide personalized interventions to keep the learners engaged in learning process. Design/methodology/approach Recent research regarding personalized Web-based educational systems demonstrates learner’s motivation to be an essential component of the learning model. This is because of the fact that low motivation results in either students’ less engagement or complete drop out from the learning activities. A learner motivation model is considered to be a set of perceptions and beliefs that the system has developed about a learner. This includes both short-term and long-term motivations of leaners. Findings This study proposed a framework of a domain independent learners’ motivation model based on firm educational theories. The proposed framework consists of two modules. The primary module deals with real-time identification of motivation and logging off activities such as login, forum participation and adherence to assessment deadline. Secondary module maintains the profile of leaners associated with both short-term and long-term motivation. A study was conducted to verify the impact of learners’ motivation model and personalized interventional strategies based on proposed model, using Systematical Information Education Method assessment standards. The results show an increase in motivational index and the characteristics associated with motivation during the conducted study. Originality/value Motivational diagnosis is important for both traditional classrooms and Web-based education systems. It is one of the major elements that contribute in the success of the learning process. However, dropout rate among online students is very high, which leads to incorporate motivational elements in more personalized way because motivated students will retain the course until they successfully complete it. Hence, identifying learner’s motivation, updating learners’ motivation model based on this identification and providing personalized interventions are the key for the success of Web-based educational systems.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Juan Fang ◽  
Qiangang Zheng ◽  
Haibo Zhang ◽  
Chongwen Jin

Abstract Aero-engine on-board steady state model is an important part of many advanced engine control algorithms. In order to build a high accuracy and real-time steady-state onboard model in a large envelope, an ICPSM (improved compact propulsion system model) based on batch normalize neural network is proposed in this paper. Compared with piecewise linearization model and support vector machine model, conventional CPSM which is mainly composed of baseline model and nonlinear sub model has the advantages of high real-time performance and small data storage. However, as the similarity conversion error increases with the distance from the design point, the cumulative error of the conventional baseline model also increases, which makes the model unable to maintain high accuracy in the full envelope. Thus, a high accuracy baseline model in full envelope based on batch normalize neural network is proposed in this paper. The simulation result shows that compared with the conventional compact propulsion system model, the percentage error of parameters of the improved compact propulsion system model based on the batch neural network is reduced by two times, the single step operation time is reduced by 18%, and the data storage of the onboard model is reduced as well.


Author(s):  
Huiyu Sun ◽  
Guangming Song ◽  
Zhong Wei ◽  
Ying Zhang

Purpose This paper aims to tele-operate the movement of an unmanned aerial vehicle (UAV) in the obstructed environment with asymmetric time-varying delays. A simple passive proportional velocity errors plus damping injection (P-like) controller is proposed to deal with the asymmetric time-varying delays in the aerial teleoperation system. Design/methodology/approach This paper presents both theoretical and real-time experimental results of the bilateral teleoperation system of a UAV for collision avoidance over the wireless network. First, a position-velocity workspace mapping is used to solve the master-slave kinematic/dynamic dissimilarity. Second, a P-like controller is proposed to ensure the stability of the time-delayed bilateral teleoperation system with asymmetric time-varying delays. The stability is analyzed by the Lyapunov–Krasovskii function and the delay-dependent stability criteria are obtained under linear-matrix-inequalities conditions. Third, a vision-based localization is presented to calibrate the UAV’s pose and provide the relative distance for obstacle avoidance with a high accuracy. Finally, the performance of the teleoperation scheme is evaluated by both human-in-the-loop simulations and real-time experiments where a single UAV flies through the obstructed environment. Findings Experimental results demonstrate that the teleoperation system can maintain passivity and collision avoidance can be achieved with a high accuracy for asymmetric time-varying delays. Moreover, the operator could tele-sense the force reflection to improve the maneuverability in the aerial teleoperation. Originality/value A real-time bilateral teleoperation system of a UAV for collision avoidance is performed in the laboratory. A force and visual interface is designed to provide force and visual feedback of the slave environment to the operator.


Author(s):  
Reshma P ◽  
Muneer VK ◽  
Muhammed Ilyas P

Face recognition is a challenging task for the researches. It is very useful for personal verification and recognition and also it is very difficult to implement due to all different situation that a human face can be found. This system makes use of the face recognition approach for the computerized attendance marking of students or employees in the room environment without lectures intervention or the employee. This system is very efficient and requires very less maintenance compared to the traditional methods. Among existing methods PCA is the most efficient technique. In this project Holistic based approach is adapted. The system is implemented using MATLAB and provides high accuracy.


Author(s):  
Jiyang Yu ◽  
Dan Huang ◽  
Siyang Zhao ◽  
Nan Pei ◽  
Huixia Cheng ◽  
...  

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