基于角度计体制的车载测向定位系统设计

文章主要介绍了一种基于角度计体制的车载测向定位系统设计,在简化硬件设计的同时利用一些相应的软件算法来进行处理,以提高测向的精度。另外,可利用移动站的特点实现简单多功能定位,外场实验效果令人满意。

一种角度计数字化实现方法

研究了乌兰韦伯测向系统中电容角度计听觉测向的数字化处理方法。分析了数字化处理过程中影响听觉效果的原因，为了获得类似电容角度计测向时平滑的听觉效果，采用对圆阵采样序列进行内插处理的方式，解决了听觉测向时和波束与差波束幅度突变的问题；在内插过程中进行了去混叠滤波处理，减弱了因混叠造成的副瓣升高对听觉效果的影响；数字化处理可灵活选择参与合成的阵元数，改善听觉效果。仿真试验验证了该方法的有效性。

自适应神经模糊双电位计零死区高精度舵机

电子舵机的输出轴角位移反馈方式及控制算法直接影响舵机的性能和可控输出角度范围。目前成熟的舵机控制方式是经典PID,存在超调或稳定性差等缺点;采用单个微型电位计因其制造几何局限导致舵机可控闭环角度无法360°可控;采用绝对编码器或霍尔角度传感器进行角度全反馈又会带来静态稳定性差,体积大价格昂贵等弊端;基于此,提出自适应神经模糊算法控制,空间180°相位差互补全反馈的双电位计角度传感器的测量方法,实现舵机360°无死区输出;设计单总线协议和自适应神经模糊控制算法,增强舵机扩展性与稳定的控制性;制作了样机进行测试实验。实验结果表明:自适应神经模糊双电位计角度传感器舵机具有很低的成本,以实现准确整周角位移输出,拥有无超调和稳定性好等优点。

漆膜光泽测定技术及其应用

叙述了漆膜光泽测定的技术基础与方法标准,介绍了漆膜多角度光泽计国内外开发现状及典型仪器特征,并对影响漆膜光泽的因素作了粗浅地探讨。

专用汽车展望(续)

云梯的倾斜矫正装置(图22)是为了能在路面倾斜的场合使用云梯而设置的把左右各5°内的倾斜矫正到铅垂状态的装置。30m 以上的云梯消防车必须安装自动矫正装置。云梯上的升降机(图23)是为了救护遇难人员或供作业人员使用,升降机沿着云梯的方向上下移动。常用的升降机能载重120kg,能以0.5～1m/sec 的速度上升,0.5～1.

Research on reasonable winding angle of ribbons of Flat Steel Ribbon Wound Pressure Vessel

Flat Steel Ribbon Wound Pressure Vessels (FSRWPVs) are used in many important industry areas. There is no such kind of pressure vessel exploding on operation for its reasonable structure design. Many explosion experiments on Flat Steel Ribbon Wound Pressure Vessel showed that their limited load pressure is related to the winding angle of the steel ribbons. FSRWPVs with reasonable winding angle have better security and lower cost. Reasonable angels given at the end of this paper facilitate engineering design.

Attitude Optimization Algorithm of GFIMU with Installation Errors

Taking the accelerometer installation errors into consideration, the attitude optimization algorithm of Gyro Free Inertial Meastement Unit （GFIMU） is studied in the high spinning condition in this paper. A ten-accelerometer configuration is designed so as to establish a mathematical model to acquire the angular speeds in the case of installation errors. Precision of the algorithm is evaluated by using damping GaussNewton method. A large amotmt of sinmlation results show that ff the accelertlmter＇s angleinstallation errors main-tain small （〈5°）, the errors of attitude angles can be limited within ±1°. Hence, the algorithm has a great applicable value in engineering.

Sealing Ability of Spherical Hull Transfer Skirts

An improved spherical, movable transfer skirt for autonomous submersibles has been devised. It was designed to permit the transfer of equipment and personnel from a submersible to the pressure chamber of an oil storage sea-bed structure. It also allowed mating at large vertical angles while the submersible remained horizontal. Seal failure modes and procedures for analyzing the sealing ability of the mating flange of the hull transfer skirt were thoroughly analyzed using conservative estimation methods. In the analysis, sea currents and mating angles were considered. Results showed that when considering the effects of currents, spherical radius and mating angle, their influence on seal ring failure should be considered first. The critical mating depth for a seal ring failure was larger than for either sliding or rotational failure modes. The critical mating depth can be used to determine the mating method of the submersible. The analytical procedures and results can be used as a reference for the design of spherical hull transfer skirts.

Numerical assessment on improving multistage centrifugal impeller performance by changing inlet skew angle at impeller inlet

Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid dynamics.The purpose of this work is to investigate the influences of lean angle at the blade tip of the impeller inlet.Four variations of lean angles,that is,8°,10°,15° and 20°,were made at first stage impeller.Reynolds Average Navier Stokes equation was used in simulation together with a shear?stress transport(SST) k-w turbulence model and mixing-plane approach,respectively.Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required.A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the impeller without excessive increase in manufacturing cost caused by the secondary flow.The results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage,which in turn results in substantial fluid energy loss not only in the impeller but also in the guide vane downstream of impeller.The numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.

Study on the musculoskeletal body for quadruped robots with spinning gait

The walking creatures' athletic ability is related to their body' s musculoskeletal system.A kind of musculoskeletal body for quadruped robots is developed,which will be used to assist the leg mechanism to achieve spinning gait in order to improve the robot mobility in unstructured environment.A bionic-flexible-spine model driven by pneumatic artificial muscles(PAMs) is proposed.Because the body has the flexible property,the robot can achieve spinning gait quickly,which is similar to walking creatures by coordinated movement between body bending and legs side-swing.The kinematics of the bending of the musculoskeletal body and side-swing of leg mechanism of quadruped robot for spinning gait are studied.According to the stability analysis of spinning gait,the relationship between body bending angle and leg swing angle can be determined.The PID controller is designed to conduct the bending experiment,and the bending characteristic of the musculoskeletal body is studied.Experimental results show that the biggest bending angle of the musculoskeletal body can reach 30°.

Direction Dependent EPR＇s Entanglement and the ＂Metabrain＂

The Einstein, Podolsky, and Rosen （EPR） entanglement problem for spin ~ particles is discussed for last moment arbitrary changes in the angles between the axes of the measurements of the spin components within the ＂metabrain＂ dream analogy paradigm for the interpretation of quantum theory. No ＂spooky＂ action at a distance is required. The ＂metabrain＂ produces a plethora of correlated streams of consciousness which are the totality of observable reality. The mental world and the observable physical world are the same. As in a dream, there are no independently existing observable objects; for an object to exist it must be observed. In this paradigm there is mutual interaction between the streams of consciousness and the ＂metabrain.＂ The non-observable ＂metabrain＂ is the source of the non-local hidden variables which produce our observations. The currents of this ＂metabrain＂ are the quantum probability amplitudes and the firing of the ＂synapses＂ result in our conscious observations. The Born probability rule for quantum calculations is derived within this paradigm and helps to resolve the EPR paradox.

Nuclear Level Density with Non-zero Angular Momentum

The statistical properties of interacting fermions have been studied for various angular momentum with the inclusion of pairing interaction. The dependence of the critical temperature on angular momentum for several nuclei, have been studied. The yrast energy as a function of angular momentum for 28Si and 24 Mg nuclei have been calculated up to 60.0 MeV of excitation energy. The computed limiting angular momenta are compared with the experimental results for ^26Al produced by ^12C＋ 14N reaction. The relevant nuclear level densities for non-zero angular momentum have been computed for ^44Ti and ^136 Ba nuclei. The results are compared with their corresponding values obtained from the approximate formulas.

Synergistic effect of a new wedge-bond-type anchor for CFRP tendons

In order to improve the anchoring force of anchors for carbon fiber reinforced polymer(CFRP) tendons further, a new wedge-bond-type anchor for CFRP tendons was developed. The increment in anchoring force induced by the clamping segment of anchor was studied. Taking the deformation of all parts in clamping segment in the transverse direction into consideration, the calculation formula for the increment of anchoring force was proposed based on the linear elastic hypotheses. The proposed model is verified by experiments and conclusions are drawn that the anchoring force is influenced mainly by the inclination angle of clamping pieces, the length of clamping part and the thickness of bonding medium. Especially, the thickness of bonding medium should be lowered in design to improve the synergistic effect of anchors.

A new measuring method for maximal length, width and thickness dimensions of coarse aggregates

In order to establish a new method for measuring the dimensions of coarse aggregates, five different-size flat and elongated (F&E) coarse aggregates were glued into two specimens by epoxy resin, respectively, and slice images were obtained by X-ray CT, then the aggregates were extracted by the fuzzy c-means clustering algorithm. Attributions of the particle on different cross-sections were determined by the ‘overlap area method’. And unified three-dimensional Cartesian coordinate system was established based on continuous slice images. The coefficient values of spherical harmonics descriptor representing particles surface profile were gained, then each scanned particle was represented by 60×120 discrete points conformably with spherical harmonics descriptor. The chord length and direction angles were determined by the calculation. With the major axis (L) and orthogonal axis (W and T), the calculated results were compared with those measured by caliper. It is concluded that the new L, W, and T dimension measuring method is able to take the place of the present manual measurement.

Research on the Causes and Coping Strategies of the Land Subsidence Caused by the Tunnel Construction Projects

In this paper, we conduct research on the causes and coping strategies of the land subsidence caused by the tunnel construction projects. We analyze the issues from the following of the perspectives. （1） Analysis method. To solve large scale system of the development of computer hardware and the numerical calculation method, we use the basic analysis to deal with it. （2） The empirical of methods. Ground motion is usually leads to the basic development of the inclined tunnel surface vertical displacement, the result of the movement process can turn to a settling tank. （3） Machine learning based approaches. In one of biggest difficulties when using neural network method is to obtain all possible parameters related to ground subsidence, we use the machine learning model to handle the challenge. In the final part, we show prospect for the future research, we will combine more numerical analysis tools to optimize the current methodology.

Research on the Fusion of Guangxi MiaoJin and Modern Arts and Crafts Design from the Perspectives of Aesthetic and Cultural Inheritance

In this paper, we conduct research on the fusion of the Guangxi MiaoJin and modem arts and crafts design from the perspectives of aesthetic and the cultural inheritance. From angles of folk embroidery patterns modelling characteristics are analyzed： include strong decorative and practical; the integrity of the vivid and concise; symbolic connotation deeply; simple random nature; handed down from generation to generation program. Discusses the forming characteristic of folk embroidery modelling is not an accidental phenomenon of art, but has a profound folk custom, economy, religion, and history of aesthetics, with typical regional culture characteristics. The research of folk embroidery in the status of folk art is of great significance. In the future, we will combine more literature review to optimize our current research and broaden the research boundary.

CFD Investigation of Compressible Low Angles of Attack Flow over the Missile

In modem missile design, the operation of a missile aerodynamics with angles of attack is required to serve a demand on the maneuverability. The key aero-physics is the development of vortices and its interaction to the control surface such as wing and fins. This paper thus presents the investigation of the missile flow field at 4° and 8° degrees of angles of attack. The Mach numbers for both case were varied from 0.6 to 5.5. Here, the Steady Reynolds-Averaged Navier-Stokes （SRANS） equations with standard κ-ε turbulence model were selected. The numerical results of aerodynamics coefficients （both force and moment） were compared against semi-empirical data computed using Missile DatCOM. The results revealed the development of vortices observed and their interaction with fin at the rear part of the missile.

Mixture steering law design for control moment gyroscopes

Focusing on the singularities of a spacecraft using control moment gyros(CMGs)to do the large angle maneuvers,a new mixture steering law is proposed to avoid the singularities.According to this method,if the CMGs are far away from the singularity,the Moore-Penrose pseudo-inverse steering law(MP)is used directly.If the CMGs are close to the singularity,instead of solving the inverse matrix,a set of optimal gimbal angles are sought for the singular measurement to reach the maximum,which can avoid the singularities.Simulations show that the designed steering law enables the spacecraft to carry out the large angle maneuver and avoid the singularities simultaneously.

Aerodynamics Design of Two-stage Vane-less Counter-rotating Turbinec

It is one of the most efficient ways to greatly improve aero-engines' performance by utilizing vaneless counterrotating turbine(VCRT) technology.To supply sufficient power,VCRT turns to be high Mach number,large flow angle at high-pressure turbine(HPT) rotor exit,and low blade camber angle,which increase difficulties to turbine design.As the axial velocity ratio of HPT rotor is much larger than the conventional ones,the optimal selection of VCRT velocity triangles based on theoretical analysis is developed,and how the efficiency varied by HPT stator/rotor exit flow angle is also figured out.The key points to design a high efficient practicable VCRT are to select velocity triangles that are characterized by low flow coefficient,high outlet flow angle and large axial velocity ratio of HPT rotor.Meanwhile,performance comparison between convergent blade and convergent-divergent blade shows the latter is more appropriate for VCRT.