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An aerodynamic study is presented for controlled canard configuration of a target unmanned air vehicle (TUAV) at cruise Mach number between 0.7 and 0.85, using a solid rocket motor as power. The analysis was focused on the longitudinal wind tunnel test data for learning complicated controlled canard-elements interactions and canard vortex behavior. The canard vortex interaction with tail wing of initial...
In this paper, a maneuver controller for a nonlinear six-degree-of-freedom aircraft is designed, which makes angle-of-attack, sideslip angle, and roll rate asymptotically track the reference trajectories respectively. The design procedures for angle-of-attack and sideslip angle are based on backstepping method. Appropriate cost functions for angle-of-attack and sideslip angle are constructed to satisfy...
This paper presents a flexible cable model considering that tether is easy to inflect can be used for analyzing the dynamic behavior of the electro-dynamic tether (EDT) de-orbiting system. The model can describe tether inflecting and bowing under action of electro-dynamic drag and gravity gradient induced force, and the influences on electro motive force and electro-dynamic drag. Two mathematical...
This paper is concerned with image denoising approaches. The detail exponents of image transformed by Wavelet have been proved its significant heavy-tails nature. The alpha stable distribution has a generality to represent heavy-tailed and impulsive nature. However, the probability density function of such a statistics model has no closed expression. Based on a tractable approximation, BCGM model,...
3-DOF spacecraft attitude control simulators have been used for spacecraft attitude determination and control hardware verification and software development. In this paper, a automatic balancing system to reduce the gravitational torques influencing the motion of the simulator was described. The equations of motion and balancing algorithm developed for the system was deduced. The algorithm takes sensor...
To effectively wipe out random drift and extract valid signal of MEMS gyro, the methods of adaptive Kalman filtering and wavelet analysis are investigated. For the first method, the autoregressive moving average (ARMA) model of random drift is established, which is essential to the adaptive Kalman filter. For the second one, the wavelet basis, decomposition level, and threshold-choosing principle...
Autonomous hazard avoidance is a key technology for planetary pinpoint landing. In this paper, passive image based hazard detection and landing point selecting methods are presented. Craters on planetary surface are detected by edge detection, edge matching and geometry fitting. Rocks are another familiar terrain feature on planetary surface and it are detected by variance map segmentation. For landing...
Supercavitating vehicles have special characteristics from traditional underwater vehicles because of supercavitation. The motion of the vehicle tends to be unstable, and the dynamics of it is nonlinear and strongly coupled. Due to the time-varying factors, delay-dependent behavior and unmodeled dynamics of system, a simplified model is developed. For the supercavitating vehicle with the mismatched...
Based on spring time-delay feedback controller, the excited cantilever beam modeled as an inextensible Euler-Bernoulli beam is investigated for the primary resonance. The spring controller is designed to control the dynamic behavior of the nonlinear dynamic system. The method of multiple scales is utilized directly to obtain the linear equations. The effect of the feedback gain and time-delay on the...
In recent years, dynamics model and control of space robot system are the hot topics in the research field. In this paper, a new dynamics model and control strategy of space robotic system with a flexible manipulator and a liquid fuel tank are investigated. Based on Lagrange equation method, the dynamics model of the space robotic system coupling with liquid sloshing, flexibility vibration and base...
The gyro and the infrared earth sensor (IES) are two kinds of important components in satellite attitude control system. A fault detection and isolation (FDI) approach based on observer and Kalman filter is presented. Firstly, the models of gyro and IES are discussed, and a virtual linear system of satellite pitch channel is constructed. Then, an observer for fault detection and a Kalman filter for...
Space nuclear reactor systems are to be considered enabling technologies for the establishing of settlements on the Moon and on Mars. Their compactness, high power density, high reliability, long life and lower recurring cost are advantages compared to other energy sources. In addition, space nuclear reactors are capable of operating independent of the Sun, have an enhanced ability to operate in hostile...
Using aerodynamic force to finish the orbital transfer mission can save a lot of fuels and increase the payload. In this paper, After giving the mathematical description of the Aero-assisted Orbital Transfer(AOT) problem, we discrete it through the Guess-pseudospectral method and then apply SNOPT algorithm to get the optimal state trajectory. After that we do some simplify to original dynamic equations...
With the rapid development of space technology, more and more spacecrafts have been launched into space. At the same time, the number of space debris increases dramatically and the probability of collision between space debris and spacecrafts arises accordingly. Some evaluation methods should be studied to evaluate the collision effect. According to different collision modes, this paper introduces...
A new edge detection method based on the wavelet denoising and the mathematic morphology transform is presented in this paper. Firstly, the improved wavelet semisoft threshold method is used to suppress noise of image, where the algorithm of Bayes threshold is adopted to calculate the value of threshold. Secondly, A multi-scale and multi-structural elements morphological edge detection algorithms...
A new idea of identification method based on isolation characteristic points is proposed to solve the transfer function identification problem such as the practical electrical servo system which contains some nonlinear items. The characteristic points are chosen from the system frequency characteristic curve, and can be adjusted alone by complex adjusting coefficients of the preliminary transfer function...
The high accuracy accelerometer can be demarcated in multiposition tumbling experiment under 1g gravitational field. The g2 observation model of Two Orthometric Accelerometers can eliminate the corner error. there is a serious multicollinearity exit in this system because some model coefficient mix together. In view of above question, this article has given the arithmetic of Empirical Bayes Estimation(EB),...
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