Distributed Atmospheric Turbulence Model for Helicopter Flight Simulation and Handling-Quality Analysis

2017 ◽  
Vol 54 (1) ◽  
pp. 190-198 ◽  
Author(s):  
Honglei Ji ◽  
Renliang Chen ◽  
Pan Li
Keyword(s):  
Atmospheric Turbulence ◽  
Turbulence Model ◽  
Flight Simulation ◽  
Quality Analysis ◽  
Helicopter Flight ◽  
Handling Quality

Distributed Turbulence Model with Rigorous Spatial Cross-Correlation for Simulation of Helicopter Flight in Atmospheric Turbulence

2019 ◽  
Vol 64 (4) ◽  
pp. 1-13
Author(s):  
Honglei Ji ◽  
Renliang Chen ◽  
Pan Li
Keyword(s):  
Atmospheric Turbulence ◽  
Turbulence Model ◽  
Cross Correlation ◽  
Turbulence Models ◽  
Flight Test ◽  
Longitudinal Direction ◽  
Flight Simulation ◽  
Quality Analysis ◽  
Frequency Range ◽  
Helicopter Flight

This paper presents a distributed turbulence model with rigorous spatial cross-correlation for helicopter flight simulation in atmospheric turbulence and for future handling-quality analysis. First, digital filters with longitudinal correlations of the von Kármán turbulence are developed to generate discrete turbulence velocity components. Meanwhile, transverse turbulence correlations are considered by relating the filters in different positions with mathematically rigorous spatial cross-correlation. Then, the distributions of the related filters on the transverse plane in front of helicopter and their velocity components in the longitudinal direction of airspeed, as well as turbulence models of helicopter aerodynamic surfaces, are established. Finally, a flight dynamics model coupled with the turbulence model is developed and validated against the flight-test data. The proposed model can achieve accurate real-time simulations of helicopter response to atmospheric turbulence in the frequency range of interest of handling qualities. The effect of transverse turbulence correlations on helicopter frequency response is also analyzed. The results show that the simulation model regardless of transverse turbulence correlations would aggravate the "rotor-to-body attenuation" effect of the main rotor and therefore underpredict the helicopter roll, pitch, and heave rate responses to atmospheric turbulence in the frequency range of interest.

Helicopter Rotor Blade Flexibility Simulation for Aeroelasticity and Flight Dynamics Applications

2014 ◽  
Vol 59 (4) ◽  
pp. 1-18 ◽  
Author(s):  
Ioannis Goulos ◽  
Vassilios Pachidis ◽  
Pericles Pilidis
Keyword(s):  
Real Time ◽  
Rotor Blade ◽  
Flight Dynamics ◽  
Integrated Approach ◽  
Flight Simulation ◽  
Response Characteristics ◽  
Helicopter Flight ◽  
Finite State ◽  
The Time Domain ◽  
Blade Loads

This paper presents a mathematical model for the simulation of rotor blade flexibility in real-time helicopter flight dynamics applications that also employs sufficient modeling fidelity for prediction of structural blade loads. A matrix/vector-based formulation is developed for the treatment of elastic blade kinematics in the time domain. A novel, second-order-accurate, finite-difference scheme is employed for the approximation of the blade motion derivatives. The proposed method is coupled with a finite-state induced-flow model, a dynamic wake distortion model, and an unsteady blade element aerodynamics model. The integrated approach is deployed to investigate trim controls, stability and control derivatives, nonlinear control response characteristics, and structural blade loads for a hingeless rotor helicopter. It is shown that the developed methodology exhibits modeling accuracy comparable to that of non-real-time comprehensive rotorcraft codes. The proposed method is suitable for real-time flight simulation, with sufficient fidelity for simultaneous prediction of oscillatory blade loads.

Objective and subjective evaluations of flight simulator fidelity

2012 ◽  
Vol 25 (0) ◽  
pp. 91 ◽  
Author(s):  
Li Wong ◽  
Georg Meyer ◽  
Emma Timson ◽  
Philip Perfect ◽  
Mark White
Keyword(s):  
Tracking Error ◽  
Flight Simulation ◽  
Flight Training ◽  
Motion Platform ◽  
Subjective Data ◽  
Helicopter Flight ◽  
Objective Performance ◽  
Objective Performance Measures ◽  
Simulator Motion ◽  
Task Oriented

There is interest in how pilots perceive simulator fidelity and rate self-performance in virtual reality flight training. Ten participants were trained to perform a target tracking task in a helicopter flight simulation. After training objective performance, the median tracking error, was compared to subjective self-evaluations in a number of flying conditions where the cues available to our pilots were manipulated in a factorial design: the simulator motion platform could be active or static, audio cues signalling the state of the turbine could be those used during training, non-informative, or an obviously different but informative ‘novel’ sound. We tested participants under hard and easy flying conditions. Upon completion of each test condition, participants completed a 12-statement Likert-scale with items concerning their performance and helicopter simulator fidelity. Objective performance measures show that flight performance improved during training and was affected by audio and motion cues. The subjective data shows that participants reliably self-evaluated their own performance and simulator fidelity. However, there were instances where subjective and objective measures of performance or fidelity did not correlate. For example, although participants rated the ‘novel’ turbine sound as having low fidelity, it behaviourally caused no difference with respect to the turbine sound used in training. They were also unable to self-evaluate outcome of learning. We conclude that whilst subjective measures are a good indicator of self-performance, objective data offers a valuable task-oriented perspective on simulator fidelity.

Basic Pattern in Atmospheric Turbulence Model

2004 ◽  
Vol 41 (6) ◽  
pp. 845-848 ◽  
Author(s):  
Fu Zun-Tao ◽  
Zhang Lin ◽  
Liu Shi-Da ◽  
Liu Shi-Kuo
Keyword(s):  
Atmospheric Turbulence ◽  
Turbulence Model ◽  
Basic Pattern
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