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Publisher: Cambridge University Press   (Total: 387 journals)

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 Aeronautical Journal, TheNumber of Followers: 7      Hybrid journal (It can contain Open Access articles) ISSN (Print) 0001-9240 - ISSN (Online) 2059-6464 Published by Cambridge University Press  [387 journals]
• AER volume 123 issue 1269 Cover and Front matter
• PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.128
Issue No: Vol. 123, No. 1269 (2019)

• AER volume 123 issue 1269 Cover and Back matter
• PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.129
Issue No: Vol. 123, No. 1269 (2019)

• A new hybrid control methodology for a morphing aircraft wing-tip
actuation mechanism
• Authors: M. J. Tchatchueng Kammegne; R. M. Botez, L. T. Grigorie, M. Mamou, Y. Mébarki
Pages: 1757 - 1787
Abstract: The focus of this paper is on the modelling of miniature electromechanical actuators used in a morphing wing application, on the development of a control concept for these actuators, and on the experimental validation of the designed control system integrated in the morphing wing-tip model for a real aircraft. The assembled actuator includes as its main component a brushless direct current motor coupled to a trapezoidal screw by using a gearing system. A Linear Variable Differential Transformer (LVDT) is attached on each actuator giving back the actuator position in millimetres for the control system, while an encoder placed inside the motor provides the position of the motor shaft. Two actuation lines, each with two actuators, are integrated inside the wing model to change its shape. For the experimental model, a full-scaled portion of an aircraft wing tip is used with the chord length of 1.5 meters and equipped on the upper surface with a flexible skin made of composite fibre materials. A controllable voltage provided by a power amplifier is used to drive the actuator system. In this way, three control loops are designed and implemented, one to control the torque and the other two to control the position in a parallel architecture. The parallel position control loops use feedback signals from different sources. For the first position control loop, the feedback signal is provided by the integrated encoder, while for the second one, the feedback signal comes from the LVDT. For the experimental model, the parameters for the torque control, but also for the position control-based encoder signal, are implemented in the power amplifier energising the electrical motor. On the other hand, a National Instruments real-time system is used to implement and test the position control-based LVDT signal. The experimental validation of the developed control system is realised in two independent steps: bench testing with no airflow and wind-tunnel testing. The pressure data provided by a number of Kulite sensors equipping the flexible skin upper surface and the infrared thermography camera visualisations are used to estimate the laminar-to-turbulent transition point position.
PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.106
Issue No: Vol. 123, No. 1269 (2019)

• A real-time on-chip network architecture for mixed criticality aerospace
systems
• Authors: S. Majumder; J.F.D. Nielsen, A. La Cour-Harbo, H. Schiøler, T. Bak
Pages: 1788 - 1806
Abstract: Integrated Modular Avionics enables applications of different criticality levels to share the same hardware platform with an established temporal and spatial isolation. On-chip communication systems for such platforms must support different bandwidth and latency requirements of applications while preserving time predictability. In this paper, our concern is a time-predictable on-chip network architecture for targeting applications in mixed-criticality aerospace systems. The proposed architecture introduces a mixed, priority-based and time-division-multiplexed arbitration scheme to accommodate different bandwidth and latency in the same network while preserving worst-case time predictability for end-to-end communication without packet loss. Furthermore, as isolation of erroneous transmission by a faulty application is a key aspect of contingency management, the communication system should support isolation mechanisms to prevent interference. For this reason, a sampling port and isolated sampling buffer-based approach is proposed with a transmission authorisation control mechanism, guaranteeing spatial and temporal isolation between communicating systems.
PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.80
Issue No: Vol. 123, No. 1269 (2019)

• Longitudinal and lateral aerodynamic characterisation of reflex wing
Unmanned Aerial Vehicle from flight tests using Maximum Likelihood, Least
Square and Neural Gauss Newton methods
• Authors: S. Saderla; R. Dhayalan, K. Singh, N. Kumar, A. K. Ghosh
Pages: 1807 - 1839
Abstract: In this paper, longitudinal and lateral-directional aerodynamic characterisation of the Cropped Delta Reflex Wing (CDRW) configuration–based unmanned aerial vehicle is carried out by means of full-scale static wind-tunnel tests followed by full-scale flight testing. A predecided set of longitudinal and lateral/directional manoeuvres is performed to acquire the respective flight data, using a dedicated onboard flight data acquisition system. The compatibility of the acquired dynamics is quantified, in terms of scale factors and biases of the measured variables, using Kinematic consistency check. Maximum likelihood (ML), least squares and newly emerging neural Gauss–Newton (NGN) methods were implemented for a wing-alone delta configuration, mainly to capture the dynamic derivatives for both longitudinal and lateral directional cases. Estimated damping and weak dynamic derivatives, which are in general challenging to capture for a wing alone configuration, are consistent using ML and NGN methods. Validation of the estimated parameters with aerodynamic model is performed by proof-of-match exercise and are presented therein.
PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.70
Issue No: Vol. 123, No. 1269 (2019)

• A proposed solution for airborne delays: linear holding
• Authors: O. Sahin
Pages: 1840 - 1856
Abstract: This study is aimed at establishing a linear holding (LH) procedure instead of a conventional air holding stack to minimize the effects of airborne delays in terms of air traffic management and fuel consumption. This paper uses both actual flight data and the Base of Aircraft Database (BADA) model to obtain fuel consumption for level flight and descent segments, separately.The total fuel savings obtained by using actual flight data (16%) and the BADA model (10%) indicate that the LH is found to be more advantageous compared to a conventional holding procedure. Furthermore, the recommended LH procedure could be a promising solution for keeping aircraft in a narrow area that could be considered to be an effective method for airspace usage.
PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.78
Issue No: Vol. 123, No. 1269 (2019)

• Heat transfer rate and surface pressure measurements in short duration
hypersonic flow
• Authors: M. Saiprakash; C. Senthil Kumar, G. Kadam Sunil, S.P. Rampratap, V. Shanmugam, G. Balu
Pages: 1857 - 1880
Abstract: Experiments were carried out with air as the test gas to obtain the surface convective heating rate and surface pressure distribution on blunt and sharp cone models flying at hypersonic speeds. Tests were performed in a hypersonic shock tunnel at two different angles of attack: ${0}^\circ$ and ${5}^\circ$ with angles of rotation $\phi = {0}^\circ, {90}^\circ$ , and ${180}^\circ$ . The experiments were conducted at a stagnation enthalpy of 1.4MJ/kg, flow Mach number of 6.56 and free stream Reynolds number based on the model length of $9.1 \times {10}^{5}$ . The effective test time of the shock tunnel is 3ms. The results obtained for cone model with a bluntness ratio of 0.2 were compared with sharp cone models for $\alpha ={0}^\circ$ . The measured stagnation heat transfer value matched well with the theoretical value predicted by the Fay and Riddell correlation and with the CFD results.
PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.116
Issue No: Vol. 123, No. 1269 (2019)

• Magnetic attitude tracking control of gravity gradient microsatellite in
orbital transfer
• Authors: Liang Sun; Zhiwen Wang, Guowei Zhao, Hai Huang
Pages: 1881 - 1894
Abstract: The problem of the magnetic attitude tracking control is studied for a gravity gradient microsatellite in orbital transfer. The contributions of the work are mainly shown in two aspects: (1) the design of an expected attitude trajectory; (2) a method of the magnetic attitude tracking control. In orbital transfer, the gravity gradient microsatellite under a constant thrust shows complicated dynamic behaviours. In order to damp out the pendular motion, the gravity gradient microsatellite is subject to the the attitude tracking problem. An expected attitude trajectory is designed based on dynamic characteristics revealed in the paper, which not only ensures the flight safety of the system, but also reduces the energy consumption of the controller. Besides, the control torque produced by a magnetorquer is constrained to lie in a two-dimensional plane orthogonal to the magnetic field, so an auxiliary compensator is proposed to improve the control performance, which is different from existing magnetic control methods. In addition, a sliding mode control based on the compensator is presented, and the Lyapunov stability analysis is performed to show the global convergence of the tracking error. Finally, a numerical case of the gravity gradient microsatellite is studied to demonstrate the effectiveness of the proposed tracking control.
PubDate: 2019-11-01T00:00:00.000Z
DOI: 10.1017/aer.2019.112
Issue No: Vol. 123, No. 1269 (2019)

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