Observability of Inertial Navigation System

To improve the observability of strapdown inertial navigation system and the effectiveness of Kalman filter in the navigation system, the method of estimating the observability is analyzed based on eigenvalues and eigenvectors which are proved to be availabe, on this basis two-position alignment technigue is applied. The simulation shows that two-position alignment really makes the system＇s observability change from being incomplete to being complete, and the test method based on eigenvalues and eigenvectors is available to determine the observability of every state vector.     

New autonomous celestial navigation method for lunar satellite

Celestial navigation system is an important autonomous navigation system widely used for deep space exploration missions, in which extended Kalman filter and the measurement of angle between celestial bodies are used to estimate the position and velocity of explorer. In a conventional cartesian coordinate, this navigation system can not be used to achieve accurate determination of position for linearization errors of nonlinear spacecraft motion equation. A new autonomous celestial navigation method has been proposed for lunar satellite using classical orbital parameters. The error of linearizafion is reduced because orbit parameters change much more slowly than the position and velocity used in the cartesian coordinate. Simulations were made with both the cartesiane system and a system based on classical orbital parameters using extended Kalman filter under the same conditions for comparison. The results of comparison demonstrated high precision position determination of lunar satellite using this new m     

Complete characterization of strictly positive real regions and robust strictly positive real synthesis method

The concept of weak strictly positive real regions is introduced, and its properties are discussed . By using the complete discrimination system for polynomials, complete characterization of the (weak) strictly positive real regions for transfer functions in coefficient space is given. A new effective method for robust strictly positive real synthesis is proposed. This method results in necessary and sufficient conditions for low-order stable interval polynomials and segment polynomials, and is also efficient for high-order cases. Numerical examples are provided to illustrate the effectiveness of this method.     

Mixed H2/H∞ State Feedback Attitude Control of Microsatellite Based on Extended LMI Method

For the appearance of the additive perturbation of controller gain when the controller parameter has minute adjustment at the initial running stage of system,to avoid the adverse effects,this paper investigates the mixed H_2/H_∞ state feedback attitude control problem of microsatellite based on extended LMI method.Firstly,the microsatellite attitude control system is established and transformed into corresponding state space form.Then,without the equivalence restriction of the two Lyapunov variables of H_2 and H∞performance,this paper introduces additional variables to design the mixed H_2/H_∞ control method based on LMI which can also reduce the conservatives.Finally,numerical simulations are analyzed to show that the proposed method can make the satellite stable within 20 s whether there is additive perturbation of the controller gain or not.The comparative analysis of the simulation results between extended LMI method and traditional LMI method also demonstrates the effectiveness and feasibility of the proposed method in this paper.     

Mode Ⅱ fracture analysis of double edge cracked circular disk subjected to different diametral compression

A detailed analysis of mode Ⅱ stress intensity factors(SIFs) for the double edge cracked Brazilian disk subjected to different diametral compression is presented using a weight function method. The mode Ⅱ SIFs at crack tips can be obtained by simply calculating an integral of the product of mode Ⅱ weight function and the shear stress on the prospective crack faces of uncracked disk loaded by a diametral compression. A semi-analytical formula for the calculation of normalized mode Ⅱ SIF, fⅡ , is derived for different crack lengths (from 0. 1 to 0.7) and inclination angles (from 10° to 75°) with respect to loading direction. Comparison between the obtained results and finite element method solutions shows that the weight function method is of high precision. Combined with the authors' previous work on mode Ⅰ fracture analysis, the new specimen geometry can be used to study fracture through any combination of mode Ⅰ and mode Ⅱ loading by a simple alignment of the crack relative to the diameter of compression loading, and to obtain pure mode Ⅱ crack extension. Another advantage of this specimen geometry is that it is available directly from rock core and is also easy to fabricate.     

Three-dimensional numerical manifold method for heat conduction problems with a simplex integral on the boundary

The three-dimensional numerical manifold method(3D-NMM), which is based on the derivation of Galerkin’s variation, is a powerful calculation tool that uses two cover systems. The 3D-NMM can be used to handle continue-discontinue problems and extend to THM coupling. In this study, we extended the 3D-NMM to simulate both steady-state and transient heat conduction problems. The modelling was carried out using the raster methods(RSM). For the system equation, a variational method was employed to dri...     

Reliability Analysis of Production System of Fully-Mechanized Face Based on Output Statistic

Production system of fully-mechanized face is a complicated system composed of human, machine and environment, meantime influenced by various random factors. Analyzing the reliability of system needs plentiful data by means of system faults statistic. Based on the viewpoint that shift output of fully-mechanized face is the result of various random factors＇ synthetical influence, the process of how to analyze its reliability was deduced by using probability theory, symbolic statistics theory and systematic reliability theory combined with the concrete case study in this paper. And it has been proved that this method is feasible and valuable.     

Bi-prism-based single-lens three dimensional digital image correlation system with a long working distance: Methodology and application in extreme high temperature deformation test

As a novel three dimensional digital image correlation(3 D DIC) method, the bi-prism-based single lens(BSL) 3 D DIC method has been proposed and developed in recent years. Making use of a bi-prism, this method is able to perform a 3 D DIC measurement using only a single camera. Thus, the integration level of a BSL 3 D DIC system could be much higher than that of the double-camera3 D DIC system. In this paper, using a small-angle bi-prism and a camera with a longer focal length, a special BSL 3 D DIC system with a long working distance is designed for measurements in extreme environments. The principle of the system is first studied,and practical methods are then proposed for the system set-up and the determination of system parameters. Then, feasibility of the measurement system is verified by out-of-plane rigid-body translation tests. Finally, the BSL 3 D DIC system is proven to be capable of combining with a high-temperature testing instrument to perform deformation tests in a high-temperature environment of up to 1500°C.     

New Imaging Spectrometric Method for Rotary Object

A new technique for imaging spectrometer for rotqry object based on computed-tomography is pro-posed.A discrete model of this imaging spectrometric system is established,which is accordant to actual measure-ments and convenient for computation.In computer simulations with this method,projections of the object are detected by CCD while the object is rotating,and the original spectral images are numerically reccnstructed from them by using the algorithm of computed-tomography.Simulation results indicate that the principle of the method is correct and it performs well for both broadband and narrow-band spectral objects.     

Study on the comprehensive advantage evaluation method of high-tech enterprises based on RBF artificial neural network

This paper designs an intelligent evaluation approach using a Radial Basis Function （RBF） Artificial Neural Network. We based our approach on establishing a comprehensive advantage evaluating index system that offers scientific substance for creating a development plan and the strategic management of high-tech industry and regional clusters of high-tech enterprises. Furnhermore, this paper selects some typical high-tech enterprises＇ data to make comprehensive training on the network system. Meanwhile, the paper chooses some enterprises as testing samples to test the method, the result of which proves that this method is truly effective. The research of this paper provides a comprehensive advantage evaluating and managing method for high-tech enterprise.     

Length estimation of extended targets based on bistatic high resolution range profile

The approach to estimate the length of extended targets by using the bistatic high resolution range profile (HRRP) is analyzed in this paper. The relationship between the bistatic HRRP and the monostatic HRRP of extended targets are investigated. It is demonstrated by simulations that the target length measured by the bistatic HRRP is more meaningful and accurate than that by the monostatic HRRP, though the monostatic HRRP has been well developed and widely used in target recognizing and classification. The estimation results of a cone shaped target are present and compared at the end of the paper. To assure the reliability of the simulation, the bistatic HRRP is obtained through the scattering field data calculated by a full-wave numerical method, FE-BI-MLFMA.     

Global optimal path planning for mobile robot based on improved Dijkstra algorithm and ant system algorithm

A novel method of global optimal path planning for mobile robot was proposed based on the improved Dijkstra algorithm and ant system algorithm. This method includes three steps： the first step is adopting the MAK-LINK graph theory to establish the free space model of the mobile robot, the second step is adopting the improved Dijkstra algorithm to find out a sub-optimal collision-free path, and the third step is using the ant system algorithm to adjust and optimize the location of the sub-optimal path so as to generate the global optimal path for the mobile robot. The computer simulation experiment was carried out and the results show that this method is correct and effective. The comparison of the results confirms that the proposed method is better than the hybrid genetic algorithm in the global optimal path planning.     

User’s Relevance of PIR System Based on Cloud Models

A new method to evaluate fuzzily user＇s relevance on the basis of cloud models has been proposed. All factors of personalized information retrieval system are taken into account in this method. So using this method for personalized information retrieval （PIR） system can efficiently judge multi-value relevance, such as quite relevant, comparatively relevant, commonly relevant, basically relevant and completely non-relevant, and realize a kind of transform of qualitative concepts and quantity and improve accuracy of relevance judgements in PIR system. Experimental data showed that the method is practical and valid. Evaluation results are more accurate and approach to the fact better.     

Wavelet solutions of Burgers’ equation with high Reynolds numbers

A wavelet method is proposed to solve the Burgers’equation.Following this method,this nonlinear partial differential equation is first transformed into a system of ordinary differential equations using the modified wavelet Galerkin method recently developed by the authors.Then,the classical fourth-order explicit Runge–Kutta method is employed to solve the resulting system of ordinary differential equations.Such a wavelet-based solution procedure has been justified by solving two test examples:results demonstrate that the proposed method has a much better accuracy and efficiency than many other existing numerical methods,and whose order of convergence can go up to 5.Most importantly,our results also indicate that the present wavelet method can readily deal with those fluid dynamics problems with high Reynolds numbers.     

Dynamic Analysis and Structural Optimization of a Novel Palletizing Robot

A novel palletizing robot is presented and developed.By using the Newton-Euler method and the principle that the instantaneous inertial force system could be transformed into a static system,the force equilibrium equations of the whole robot and its subsystem were derived and the robot’s dynamic models were established.After that,an example simulation was performed by using Matlab software and the structural optimization of the robot’s key parts were discussed and analyzed in ANSYS platform.The results show that the dynamic models are correct and can be helpful for the design,validation and kinetic control based on dynamics of this kind of palletizing robots.     

Lighting Model of the Real World in Augmented Reality

Construction of a lighting model of the real world is one of the critical aims in an augmented reality (AR) system. The theory of lighting modeling used in computer graphics(CG) is applied in this study. The position of the real light-source is first conjectured from light and shade of the registration image element by element using a ray tracking algorithm. Then the virtual light-source and virtual fiducial are constructed in the CG environment, in which, the Phong model is used to draw the light effect. By comparing the CG scene with the real image, one can modify the parameters of the lighting model over and over again, until the lighting effect of the CG scene is close enough to that of the real image. It is proved that this method works well in the indoor AR system. The method can be used feasibly in most applications with some improvements.     

A new method of choosing scales in wavelet transform for damping identification

A systematic study of the method of selecting scales in wavelet transform for damping identification in frequency domain was carried out. A method to select the scale with the modUlus at the maximum was developed by extending the range of scales. It is proved that using this method in small damping ratio and linear system, we can achieve better results in identification of the closely-spaced model.     

A Variable Structure Model Reference Adaptive Control

A variable structure model reference adaptive control problem for the nonlinear system is studied in this paper. First, according to the relative degree concept of th nonlinear control system an error equation between the outputs of the reference model and the controlled plant is derived. Then, by using the variable structrue control method, an algorithm of variable structure model reference adaptive control is deduced on the basis of a new concept of reaching law. The definition of the SISO system is introduced into the MIMO nonlinear system. Finally, as an example, a pendulum nonlinear control system is simulated to demonstrated the effectiveness of the method. The results show that the method has some advantages: the design is simple, intuitive and easy to be realized in engineering. Besides, it is of practical significance for the synthesis of nonlinear control systems.     

Simulation analysis for O-cell test of pile and the interaction of upper pile and lower pile

In this paper,the soil-pile system of O-cell test of pile is simplified as an axi-symmetric problem.By using aggregation of quadrilateral isoparametric elements to simulate pile and soil,setting Goodman’s elements between pile and soils,a method of numerical simulation analysis on O-cell test of pile is presented with the consideration of nonlinear mechanical behavior of soils and pile-soil interface.The method is applied to the analysis of a case of O-cell test of pile.The load-displacement curves and axial force curves of upper pile and lower pile obtained from the O-cell test of pile are fitted,and parameters of the mechanical model of soils and interface are determined.Analysis results validate that the numerical simulation analysis method put forward in this paper is applicable.Furthermore,the interaction and influence of upper pile and lower pile in the O-cell test are also studied with the method.The result shows that if load box is located in a soil layer with fine mechanical behavior,the interaction of upper pile and lower pile in O-cell test can be ignored generally.