摘要：Al Si10Mg porous protective structure often produces different damage forms under compressive loading,and these damage modes affect its protective *** order to well meet the service requirements,there is an urgent need to comprehensively understand the mechanical behavior and response mechanism of AlSi10Mg porous structures under compressive *** this paper,Al Si10Mg porous structures with three kinds of volume fractions are designed and optimized to meet the requirements of high-impact,strong-energy absorption,and lightweight *** mechanical behaviors of AlSi10Mg porous structures,including the stress-strain relationship,structural bearing state,deformation and damage modes,and energy absorption characteristics,were obtained through experimental studies at different loading *** damage pattern of the damage section indicates that AlSi10Mg porous structures have both ductile and brittle mechanical *** simulation studies show that the AlSi10Mg porous structure undergoes shear damage due to relative misalignment along the diagonal cross-section,and the damage location is almost at 45°to the load direction,which is the most direct cause of its structural damage,revealing the damage mechanism of AlSi10Mg porous structures under the compressive *** normalized energy absorption model constructed in the paper well interprets the energy absorption state of Al Si10Mg porous structures and gives the sensitive location of the structures,and the results of this paper provide important references for peers in structural design and optimization.

摘要：A novel unknown input reduced-order observer (UIRO) design scheme is presented. It is proved that unknown input appearing in measurement can be eliminated by a simple algebraic transformation. Then, a new UIRO design scheme is proposed via a transformation under no unknown input existing in measurement. Compared with other known results, the condition is weaker than others. So it was further reasonable. The design procedure proposed is simple and straightforward enough to be applied. An example is given to show its efficiency in fault diagnosis.

摘要：In order to propel the development of metal magnetic memory(MMM) technique in fatigue damage detection,the Jiles-Atherton model(J-A model) was modified to describe MMM mechanism in elastic stress stage.A series of rotating bending fatigue experiments were conducted to study the stress-magnetization relationship and verify the correctness of modified J-A *** MMM detection,the magnetization of material irreversibly approaches to the local equilibrium state M0 instead of global equilibrium state Man under cyclic stress,and the M0-σ curves are loops around the Man-σ *** modified J-A model is constructed by replacing Man in J-A model with M0,and it can describe the magnetomechanical effect well at low external magnetic *** the rotating bending fatigue experiments,the MMM field distribution in normal direction around cylinder specimen is similar to the stress distribution,and the calculation result of model coincides with experiment result after some necessary *** MMM field variation with time at a certain point in fatigue process is divided into three stages with the variation of stable stress-stain hysteresis loop,and the calculation results of model can explain not only the three stages of MMM field changes,but also the different change laws when the applied magnetic field and initial magnetic field are *** MMM field distribution in normal direction along specimen axis reflects stress concentration effect at artificial defect,and the magnetic signal fluctuates around the defect at late fatigue *** calculation results coincide with the initial MMM principle and can explain signal fluctuates around the *** modified J-A model can explain experiment results well,and it is fit for MMM field characterization.

摘要：The attitude tracking control problem for a satellite with parameter uncertainties and external disturbances is considered in this paper. For this class of multi-input multi-output uncertain nonlinear systems, a design method of robust output tracking controllers is proposed based on the upper-bounds of the uncertainties. Using the input/output feedback linearization approach and Lyapunov method, a control law is designed, which guarantees that the system output exponentially tracks the given desired output. The proposed controller is easy to compute and complement. Simulation results show that, in the closed-loop system, precise attitude control is accomplished in spite of the uncertainties in the system.

摘要：This paper proposes a sensor fault diagnosis method for a class of discrete-time linear time-varying (LTV) *** this paper,the considered system is firstly formulated as a descriptor system representation by considering the sensor faults as auxiliary state *** on the descriptor system model,a fault estimation filter which can simultaneously estimate the state and the sensor fault magnitudes is designed via a minimumvariance ***,a fault diagnosis scheme is presented by using a bank of the proposed fault estimation *** novelty of this paper lies in developing a sensor fault diagnosis method for discrete LTV systems without any assumption on the dynamic of *** advantage of the proposed method is its ability to detect,isolate and estimate sensor faults in the presence of process noise and measurement *** results are given to illustrate the effectiveness of the proposed method.

摘要：Reusable launch vehicle is an important way to realize fast,cheap and reliable space transportation.A combined cycle engine system provides a more efficient and flexible form of *** investigation on the research status of the combined cycle engine technology,including basic principle,research programs and classification of structure is firstly discussed in this *** the bilevel hierarchical and integrated parameters/trajectory overall optimization technologies are applied to improve the efficiency and effectiveness of overall vehicle *** are implemented to compare and analyze the effectiveness and adaptability of the two algorithms,in order to provide the technical reserves and beneficial references for further research on combined cycle engine reusable launch vehicles.

摘要：In order to realize a high-precision and continuous working function of a star sensor,we propose a new optical system *** the difficulty of the manufacturing process,the entire optical system uses a complicated Petzval *** this paper,the key design elements of the optical system applied for star sensors are presented and the most important performance parameters are *** ground test results show that the system can maintain excellent detection performance on a near-surface atmospheric *** study provides an optical system design scheme for a high-precision and continuous operating star sensor,as well as the theoretical basis for future in-atmosphere and continuous star detection technology.

摘要：With the increasing miniaturisation and integration of electronic products and the increase of heat, it is necessary to design and introduce heat sinks and install fans. The volume of electronic components, especially the height, is very important for the structural and thermal design of electronic devices. This paper presents a design scheme of an online height measurement device based on laser triangulation and commercial charge coupled device(CCD). It analyzes the principles of electronic component height measurement, and expounds the composition and working principle of the laser measurement system. In addition, the commonly used methods to determine the center position are compared and analysed. These methods include circle fitting, gray centroid and extension method or Gaussian fitting. These methods usually lead to different results. The experimental results show that the fitting speed of the gray centroid is faster. The 3 D model of components is given through measurement, and the error factors affecting measurement are analysed.