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The second-throat adjustment sheet is a key part for accurately and quickly adjusting Mach number of test section, so it is greatly significant to research the multi-condition dynamic behavior of the second-throat adjustment sheet for the high-accuracy Mach number adjustment of test section. The experimental research method is adopted to research the dynamic behavior of the second-throat adjustment...
The desirable vibration performance of the second throat centrebody of transonic wind tunnel is one of the key technologies that realize high-precision and rapid regulation of the Mach number in the wind tunnel test section. The vibration of the open centrebody of the second throat in the transonic wind tunnel is strong. The numerical simulation and test methods are adopted to conduct a study on dynamic...
The objective of the study is to determine an optimal flap damping configuration and flapping hinge location to achieve minimum hub and fuselage vibration levels simultaneously. An aeroelastic analysis of two soft in-plane two-bladed rotor is performed in conjunction with optimal control. A multi-objective bat algorithm (MOBA) approach was used to obtain the optimal design point. Under constraint...
A predictor-corrector entry guidance method satisfying the constraints of no-fly zone and waypoint is proposed in this paper. First, Gauss pseudospectral method is used to generate a reference trajectory. Based on the reference trajectory some reference points are selected which partition the entry process into several subsections. Then a predictor-corrector guidance law is developed. The trajectory...
3 Different 2-Dimentianl airfoil-engine configurations are carried out and its aerodynamic performance in subsonic flow are analyzed and discussed. It is shown from computation that configurations with boundary layer ingestion (BLI) have a better aerodynamic performance compared with a conventional configuration. The effects of BLI from the engine contribute to an acceleration of the airflow velocity...
A simple and consolidated structure, based on the general expression of Cunningham, is proposed to compute gravity potential and its derivatives up to any order. A novel normalization factor is introduced to synthesize various normalization forms into a unified one. Spherical harmonic series in a rectangular structure of all orders are constructed herein for the evaluation of arbitrary order derivatives,...
The control problem of underactuated spacecraft chaotic attitude motion is investigated based on exponential reaching law in this paper. First, the underactuated spacecraft chaotic attitude system is written in nonlinear equation form with two controls. Once the trajectory planning of angular acceleration is preset, the dynamics equation of angular velocity error can be obtained. Then, the sliding...
There will be a big load on the structure after aircraft ditching and spacecraft water recycling, which has an important effect on the safety of the capsule structure and the people inside. Therefore the research of water impact has a practical significance. Base on the wedge and arc body model, the test of the body free falling on the water has been vertically investigated. The acceleration signals...
No restrictions are imposed on the motion states of missile and target and the line of sight rotation coordinate system is introduced into the derivation of differential geometric guidance law. Then, the extended differential geometric guidance law is achieved whose scope of application is largely extended. In order to realize the derived law, instead of the complex computation of torsion command,...
This paper presents a solution to autonomous inspection of the international space station using a rigid spacecraft. Specifically, the paper presents the orbital mechanics, formation dynamics as well as rotational dynamics required to control the spacecraft relative to the space station, and then presents two PD+ controllers enabling a spacecraft to track a series of waypoints while pointing a sensor...
This paper presents a hierarchical framework to perform a coordinated tracking in three-dimensional formation maneuvers using guidance and control regulator. To accomplish the coordinated maneuvers of multiple UAVs, some levels of hierarchy from mission planning to accurate guidance law is required. It addressed a distributed and online pure pursuit law as a reference plant coupled with control parameters...
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