Coordinated flight control along a complex flight-path

Author(s):  
J.G. Thompson ◽  
X. Zhang
Author(s):  
Patrick J. O’Heron ◽  
Parviz E. Nikravesh ◽  
Ara Arabyan ◽  
Donald L. Kunz

Abstract A model is presented that can be used to simulate the highly nonlinear transient dynamics associated with advanced rotorcraft conversion processes. Multibody equations of motion of the fuselage, the tilting wing, and the rotor assembly are derived using a minimal set of coordinates. An enhanced aerodynamics model is employed to account for unsteadiness and nonlinearity in the near-wake aerodynamics, with a dynamic uniform inflow to compute the far-wake aerodynamics, and a flight control system is employed to compute the blade pitch settings that are necessary to achieve a desired flight path. The model is subjected to a demanding flight path simulation to illustrate that it can perform vertical take-off, hover, tilt-wing conversion, and high-speed forward flight maneuvers effectively.


Author(s):  
S. Dunagan ◽  
M. Fladeland ◽  
C. Ippolito ◽  
M. Knudson ◽  
Z. Young

Unmanned aircraft systems (UAS) are important assets for accessing high risk airspace and incorporate technologies for sensor coordination, onboard processing, tele-communication, unconventional flight control, and ground based monitoring and optimization. These capabilities permit adaptive mission management in the face of complex requirements and chaotic external influences. NASA Ames Research Center has led a number of Earth science remote sensing missions directed at the assessment of natural resources and here we describe two resource mapping problems having mission characteristics requiring a mission adaptive capability extensible to other resource assessment challenges. <br><br> One example involves the requirement for careful control over solar angle geometry for passive reflectance measurements. This constraint exists when collecting imaging spectroscopy data over vegetation for time series analysis or for the coastal ocean where solar angle combines with sea state to produce surface glint that can obscure the signal. Furthermore, the primary flight control imperative to minimize tracking error should compromise with the requirement to minimize aircraft motion artifacts in the spatial measurement distribution. A second example involves mapping of natural resources in the Earth’s crust using precision magnetometry. In this case the vehicle flight path must be oriented to optimize magnetic flux gradients over a spatial domain having continually emerging features, while optimizing the efficiency of the spatial mapping task. <br><br> These requirements were highlighted in recent Earth Science missions including the OCEANIA mission directed at improving the capability for spectral and radiometric reflectance measurements in the coastal ocean, and the Surprise Valley Mission directed at mapping sub-surface mineral composition and faults, using high-sensitivity magnetometry. This paper reports the development of specific aircraft control approaches to incorporate the unusual and demanding requirements to manage solar angle, aircraft attitude and flight path orientation, and efficient (directly geo-rectified) surface and sub-surface mapping, including the near-time optimization of these sometimes competing requirements.


Author(s):  
Hongchuan Song ◽  
Hao Zhan ◽  
Lu Xia ◽  
Nan Zhang

The precise tracking 3D trajectory that changes dramatically within the boundary of flight performance is the essential capability of the UAV applied to air combat, which requires that flight control law design be adapted to nonlinear characteristics of flight dynamics and solve the singularities problem during the flight. Continuous trajectory control on the basis of nonlinear dynamic inversion (NDI) is studied. The singularities problem is caused by continuous trajectory expressed by flight velocity and flight-path angles. A sudden change of flight-path axis system happens when aircraft flies along a continuous trajectory which results in singularities. A method for amending flight-path axis system is presented to solve the sudden change problem of flight-path axis system. Finally, the combination of the maneuver generator based on quaternions and amending flight-path axis system realize the precise trajectory tracking control without singularities and obtain excellent tracking characteristics.


Author(s):  
William A. Schaudt ◽  
Kristin J. Caufield ◽  
Brian P. Dyre

We examined whether flight-control performance might be improved by presenting airspeed information to peripheral areas of the visual field using virtual head-up displays (HUDs), and whether participants process these displays using peripheral, rather than central, vision. We found that, compared to a standard HUD speed indicator, a peripherally located virtual speed indicator produced superior altitude control and equivalent or better speed control. Participants' gaze dwell times were more concentrated on flight-path and altitude control information as compared to speed information for the virtual HUD speed indicator. Gaze patterns showed that participants processed the virtual speed indicator with peripheral vision while they needed to directly fixate the traditional military standard HUD speed indicator in central vision. We believe the virtual display allowed participants to acquire speed information in a manner consistent with naturally-evolved orienting processes and therefore reduced central visual field load, attentional demand, and overall mental workload, freeing resources for better flight-path control.


2019 ◽  
Vol 62 (11) ◽  
Author(s):  
Xiangke Wang ◽  
Lincheng Shen ◽  
Zhihong Liu ◽  
Shulong Zhao ◽  
Yirui Cong ◽  
...  

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