Path-attitude decoupling and flying qualities implications in hypersonic flight

Sachs, Gottfried

doi:10.1016/s0034-1223(98)80005-5

Cited by 15 publications

(6 citation statements)

References 2 publications

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“…This can provide a practical guidance law for a hypersonic vehicle to achieve periodic cruise; otherwise, it is difficult to implement accurate tracking of the altitude, as shown in Equation (10), due to the slow altitude response [37][38][39][40]. According to Equation (10), the cycle range is…”

Section: Augmented States Based Periodic Cruise Optimizationmentioning

confidence: 99%

General Periodic Cruise Guidance Optimization for Hypersonic Vehicles

Gao

Chen²,

Sun

et al. 2020

Applied Sciences

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Periodic cruise has the potential to improve the fuel efficiency of a hypersonic vehicle. However, the optimization of periodic cruise is very difficult and can only be performed inefficiently through trial-and-error due to the parameterized form. In this paper, we systematically optimized the hypersonic periodic cruise using the pseudo-spectral method (PSM) scheme. We specify the main variables as the given forms of periodic functions and parameterize the periodic guidance. The characteristic parameters can then be considered as augmented states to generate augmented dynamics. Therefore, periodic cruise optimization can be directly obtained by using GPOPS (Gauss Pseudo-spectral OPtimization Software). The numerical results demonstrate the effectiveness of the proposed method. The approach in this case study can be generalized to solve similar trajectory optimization problems that can be parameterized in a unified manner.

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Section: Augmented States Based Periodic Cruise Optimizationmentioning

confidence: 99%

General Periodic Cruise Guidance Optimization for Hypersonic Vehicles

Gao

Chen²,

Sun

et al. 2020

Applied Sciences

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“…The path-attitude consonance for conventional flights can be depicted by Eq. (5) 5) ðsÞ ðsÞ % 1 which implies that there exists a lag between the responses of and the input of . Sachs 6) pointed out that the flight speed and atmospheric density gradient of the flight environment in the near space are the primary factors for the value of T 2 .…”

Section: Main Problem Statementmentioning

confidence: 99%

“…3 of Sachs,6) it can be observed that T 2 increases with the increment of Mach number; for example, T 2 ¼ 5 s when Mach ¼ 2 and T 2 ¼ 10 s when Mach ¼ 6. Therefore, there is a clear path-attitude inconsonance such that is unable to follow quickly because the settling time is more than 30 s. In fact, when a hypersonic vehicle is at the cruising stage, the path-attitude relation can be depicted by 5) ðsÞ ðsÞ…”

Section: Main Problem Statementmentioning

confidence: 99%

“…However, compared to conventional subsonic and supersonic flight vehicles, hypersonic aircraft demonstrate unique dynamics. It should be noted that there is a severe lag of about 30 s or more between the flight path angle and pitch attitude, which is determined by the flight speed and atmospheric density gradient of the flight environment, [5][6][7] and this is a particular phenomenon for hypersonic flights. High precision flight path control is difficult to achieve due to this large lag.…”

Section: Introductionmentioning

confidence: 99%

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Practical Solution to Efficient Flight Path Control for Hypersonic Vehicles

Sun

Wang

et al. 2016

Trans. Japan Soc. Aero. S Sci.

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There is a severe lag between the pitch attitude and flight path angle of hypersonic vehicles, imposing extraordinary difficulty in achieving high-precision trajectory control. A comprehensive flight path regulation scheme is proposed to resolve this problem. The inherent relationship between the pitch attitude and flight path angle is sufficiently used to establish a feed-forward control framework where the flight path reference is directly fed into the attitude loop in order to quickly obtain the major control component. To achieve efficient tracking, an attitude control method based on active disturbance rejection control (ADRC) is proposed. The new attitude control method utilizes an extended state observer (ESO) to estimate the unknown model dynamics and external disturbances. The remaining part of control is generated by ADRC acting on the flight path angle, which plays a complementary role. The stability margin tester is used to tune the attitude controller explicitly. Finally, simulation examples are provided to demonstrate the effectiveness of the proposed method.

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“…Therefore, how to overcome the coupling effect between the loading channels and achieve accurate and unified loading of multiple channels has become a major problem in this field. The key to overcome this problem is how to only use force sensors for the decoupling control [ 12 , 13 ] of dozens of channels. Because the size of the civil aircraft is very large, only the cable of the force sensors is several kilometers in the fatigue test, and the addition of a new sensor is hardly allowed.…”

Section: Introductionmentioning

confidence: 99%

Motion Synchronous Composite Decoupling with Fewer Sensors on Multichannel Hydraulic Force Control for Aircraft Structural Loading Test System

Bai

Jiao

Yao

et al. 2018

Sensors

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The aircraft full-scale fatigue test is widely used in the modern aircraft industry for the safety of flight. Generally, the aircraft full-scale fatigue test is achieved by structural loading; multiple hydraulic actuators are used to apply load for force control. The fatigue loading test takes approximately several years. A key challenge is how to accelerate the loading frequency to shorten the total test time. Nevertheless, when pluralities of hydraulic actuator simultaneously increase the loading frequency, the mutual coupling force from the low rigidity of the aircraft structure will cause a large loading error, meaning that the test cannot be implemented. Although it is possible to reduce error by adding sensors, the force sensors need to connect several kilometers of cable. This paper proposed a novel motion synchronous composite decoupling control strategy with fewer sensors. The control method compensates the negative coupling effect of the channels by integrating the command signals and feedback signals of all channels. It can suppress coupling force and reduce errors at higher frequencies, thereby shortening the experiment time. Opposed to traditional decoupling control methods, advantages of this strategy are that it only needs force sensors and it does not need additional displacement or velocity and acceleration sensors to collect state variables for building the state space. Furthermore, it has been experimentally verified that the new motion synchronous composite decoupling control method can indeed guarantee sufficient control accuracy when the test frequency is increased. The method has great economic significance for shortening test duration.

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Path-attitude decoupling and flying qualities implications in hypersonic flight

Cited by 15 publications

References 2 publications

General Periodic Cruise Guidance Optimization for Hypersonic Vehicles

General Periodic Cruise Guidance Optimization for Hypersonic Vehicles

Practical Solution to Efficient Flight Path Control for Hypersonic Vehicles

Motion Synchronous Composite Decoupling with Fewer Sensors on Multichannel Hydraulic Force Control for Aircraft Structural Loading Test System

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