Research on Airborne Electro-Optical Tracking and Sighting System Based on Fuzzy PID and H_∞ Control

Airborne electro-optical tracking and sighting system is a three-degree-of-freedom angular position servo system which is influenced by multi-disturbance,and its control system consists of stabilizing and tracking components.Stabilizing control is applied to track angular velocity order and control multi-disturbance under airborne condition,and its robustness should be very good;tracking control is applied to compensate tracking error of angular position.A mathematical model is established by taking the control of yaw loop as example.H∞ stabilizing controller is designed by taking the advantage of H∞ control robustness and combining with Kalman filter.A fuzzy control is introduced in general PID control to design a decoupled fuzzy Smith estimating PID controller for tracking control.Simulation research shows that the control effect of airborne electro-optical tracking and sighting system based on fuzzy PID and H∞ control is good,especially when the model parameters change and the multi-disturbance exists,the system capability has little fall,but this system still can effectively track a target.

Electro-Optical Effect Measurement of Thin-Film Material Using PM Fiber Mach-Zehnder Interferometer

A polarization-maintaining （PM） fiber Mach-Zehnder （MZ） interferometer has been established to measure the EO effect of very thin film materials with optical anisotropy. Unlike a common MZ interferometer, all the components are connected via polarization-maintaining fibers. At the same time, a polarized DFB laser with a maximum power output of 10mW is adopted as the light source to induce a large extinction ratio. Here,we take it to determine the electro-optical coefficients of a very thin superlattice structure with GaAs, KTP, and GaN as comparative samples. The measured EO coefficients show good comparability with the others.

Electro-optical properties cholesteric liquid of polymer stabilized crystal film＊

Liquid crystals （LCs） and polymers are extensively used in various electro-optical applications. In this paper, normal mode polymer stabilized cholesteric LC film is prepared and studied. The effects of chiral dopant and monomer concentrations on the electro-optical properties, such as contrast ratio, driving voltage, hysteresis width and response time, are investigated. The reasons of electro-optical properties influenced by the concentrations of the materials are discussed. Through the proper material recipe, the electro-optical properties of polymer stabilized cholesteric LC film can be optimized.

Electro-optical dual modulation on resistive switching behavior in BaTiO3/BiFeO3/TiO2 heterojunction

The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide(FTO) substrate by the sol–gel method. The results indicate that the Pt/Ba TiO3/BiFeO3/TiO2/FTO heterojunction exhibits stable bipolar resistive switching characteristic, good retention performance, and reversal characteristic. Under different pulse voltages and light fields, four stable resistance states can also be realized. The analysis shows that the main conduction mechanism of the resistive switching characteristic of the heterojunction is space charge limited current(SCLC) effect. After the comprehensive analysis of the band diagram and the P–E ferroelectric property of the multilayer heterojunction, we can deduce that the SCLC is formed by the effect of the oxygen vacancy which is controlled by ferroelectric polarizationmodulated change of interfacial barrier. And the effective photo-generated carrier also plays a regulatory role in resistance state(RS), which is formed by the double ferroelectric layer Ba TiO3/BiFeO3 under different light fields. This research is of potential application values for developing the multi-state non-volatile resistance random access memory(RRAM) devices based on ferroelectric materials.

Experimental study of electro-optical-switched pulsed Nd:YAG laser

We report the specification of a compact and stable side diode-pumped Q-switched pulsed Nd：YAG laser. We ex- perimentally study and compare the performance of the pulsed Nd：YAG laser in the free-running and Q-switched modes at different pulse repetition rates from 1 Hz to 100 Hz. The laser output energy is stabilized by using a special configu- ration of the optical resonator. In this laser, an unsymmetrical concave-concave resonator is used and this structure helps the mode volume to be nearly fixed when the pulse repetition rate is increased. According to the experimental results in the Q-switched operation, the laser output energy is nearly constant around 70 mJ with an FWHM pulse width of 7 ns at 100 Hz. The optical-to-optical conversion efficiency in the Q-switched regime is 17.5%.

Electro-Optical Properties of Carbon Nanotubes Obtained by High Density Plasma Chemical Vapor Deposition

In this work, we studied the electro-optical properties of high-aligned carbon nanotubes deposited at room temperature. For this, we used the High Density Plasma Chemical Vapor Deposition system. This system uses a new concept of plasma generation: a planar coil is coupled to an RF system for plasma generation. This was used together with an electrostatic shield, for plasma densification, thereby obtaining high-density plasmas. The carbon nanotubes were deposited using pure methane plasmas. Three methods were used for the surface modification of the sample: reference substrate (silicon wafer only submitted to a chemical cleaning), silicon wafer with surface roughness generated by plasma etching, silicon wafer with a thin iron film and silicon wafer with diamond nano powder used as precursor materials. For each kind of silicon wafer surface, the carbon nanotubes were deposited with two different deposition times (two and three hours). The carbon nanotubes structural characteristics were analyzed by Atomic Force Microscope and Scanning Electronic Microscope. The carbon nanotubes electrical characteristics were observed by Raman Spectroscopy and the carbon nanotubes electro-optical properties were analyzed by current vs voltage electrical measurements and photo-luminescence spectroscopy measurements. The photoelectric effect in the carbon nanotubes were determined by photo-induced current measurements. In this work, we obtained carbon nanotubes with semiconductor properties and carbon nanotubes with metallic properties. The electro-optical effects depend strongly on the substrate preparation and the deposition parameters of the carbon nanotubes. The carbon nanotubes are high aligned and show singular properties that can be used for many applications.

Electro-optical properties of high birefringence liquid crystal compounds with isothiocyanate and naphthyl group

Liquid crystal（LC） compound with isothiocyanate and naphthyl group is an attractive high birefringence LC material,and can be used in optical devices. In this paper, the electro-optical properties of a series of this type of LC compounds were investigated. The melting points and enthalpy values of these LC compounds were higher than those of corresponding compounds with the phenyl group. These compounds exhibited high birefringence with a maximum value of 0.66. Fluorine substitution in the molecular almost does not affect the birefringence value. When these LC compounds with the naphthyl group were dissolved in a commercial LC mixture, the electro-optical properties depending on temperature were investigated. In the low-temperature region, LC mixtures with the naphthyl-group LC compounds exhibited higher viscosity than pure commercial LCs. In the high-temperature region, viscosity values very closely approached each other. When response performance was investigated, figure-of-merit（FoM） values were measured. The Fo M values of LC mixtures containing LC compounds with naphthyl group were lower than those of reference benzene LCs in the low-temperature region. However, in the high-temperature region, the results were reversed. These isothiocyanate LC compounds with naphthyl group can be applied in special fast-response LC device, particularly the ones used under high-temperature conditions.

Preparation and Microstructural,Structural,Optical and Electro-Optical Properties of La Doped Pmn-Pt Transparent Ceramics

Transparent relaxor ferroelectric ceramics of the system lanthanum modified lead magnesium niobate have been investigated for a variety of electro-optic properties could make these materials alternatives to (Pb,La)(Zr,Ti)O3. However, a study that relates the properties in function stoichiometric formula, it has not been analyzed heretofore. Therefore, in this work the effect of A-site substitution of La+3 in the characterization microstructural, structural, optical and electro-optical on (1-x)[Pb(1-3/2y)Lay(Mg1/3Nb2/3)O3]-xPbTiO3 and (1-z)[(1-x)Pb(Mg1/3Nb2/3)O3+xPbTiO3]+zLa2O3 has been performed. It was observed that the properties according to the stoichiometric formula and the PT had a maximum whose behavior was related to the addition of lanthanum in each stoichiometries.

Electro-optical properties and(E,F) phase diagram of fluorinated chiral smectic liquid crystals

Fluorinated smectic liquid crystals each with a biphenyl benzoate rigid core are investigated. Molecular structures of the studied compounds have difference only in fluorine position and the length of the carbon chain. Dielectric relaxation study and electro-optical measurements are carried out with the classical SSFLC geometry. The field-induced phase transitions are studied and the（E,T） phase diagram is established.

Analysis of electro-optical intensity modulator for bunch arrival-time monitor at SXFEL

A bunch arrival-time monitor(BAM) based on an electro-optical intensity modulation scheme is currently under development at Shanghai Soft X-ray Free-Electron Laser to meet the high-resolution requirements for bunch stability. The BAM uses a radio frequency signal generated by a pickup cavity to modulate the reference laser pulses in an electro-optical intensity modulator(EOM), and the bunch arrival-time information is derived from the amplitude change of the laser pulse after laser pulse modulation.EOM is a key optical component in the BAM system.Through the basic principle analysis of BAM, many parameters of the EOM are observed to affect the measurement resolution of the BAM system. Therefore, a systematic analysis of the EOM is crucial. In this paper, we present two schemes to compare and analyze an EOM and provide a reference for selecting a new version of the EOM.

Electro-optical Properties of Liquid Crystal Composite Materials

The liquid crystal composite materials consist of microdroplets of liquid crystals which are spontaneously formed in a matrix of a polymer at the time of its polymerization. The director configuration in liquid crystal droplets, the model of orientation of droplets, and the contrast ratios of a cell are investigated. Droplet size, spacing and distribution are readily controlled in these materials to allow optimization of displays based upon electrically controlled light scattering from the liquid crystal droplets. Preliminary experimental and theoretical studies of the light scattering and electro-optic response of new material show that these materials can offer new features suitable for large area displays and light valves.

Analytical Determination of Size and Location of Roadside Horizontal Sightline Offsets for Compound Curves

AASHTO’s guideline for geometric design of highways and similar guidelines require that roadside areas on the inside of horizontal curves be cleared of high objects to provide stopping sight distance. The guidelines have analytical models for determining the extent of clearance, known as the horizontal sightline offset or clearance offset, for simple curves. Researchers in the past have developed analytical models for clearance offsets for spiraled and reverse curves. Very few researchers developed analytical models for available sight distances for compound curves. Still missing are models for horizontal sightline offsets and locations of the offsets for compound curves. The objective of this paper is to present development of analytical models and charts for determining horizontal sightline offsets and their locations for compound curves. The paper considers curves whose component arcs are individually shorter than stopping sight distance. The resulting models and the charts have been verified with accurate values determined using graphical methods. The models and the charts will find application in geometric design of highway compound curves.

Synthesis and electro-optic properties of fluorine-containing polyimide

The fluorine-containing organic polymer was synthesized from 3, 3＇, 4, 4＇-Bisphenyltetracarboxylic （BPDA）, and 2,2-Bis （3-amino-4-hydroxyyphenyl） hexafluoropropane （6FHP）. It is a first-step preparation of a preimided hydroxy-containing polyimide, followed by the covalent bonding of an active chromophore, dispersed red 19 （DR19）, onto the backbone of the polyimide via the Mitsunobu reaction. The nonlinear optical （NLO） containing polyimide was synthesized. The differential scanning calorimeter （DSC）and thermal gravimetric analysis （TGA） exhibited Tg and the temperature Tg at which 5 % mass losses occurring of polymer were 248 and 309 ℃, respectively. A reflective electro-optic （EO） modulator using this polymer was fabricated. The optical nonlinearities were determined to be d33 = 5. 209×10^-9 esu （poling voltage of 3.6 kV, 205 ℃） and d33 =7. 418×10^-9esu （poling voltage of 3. 8 kV, 210 ℃） by the second harmonic generation method in in-situ condition at a fundamental wavelength of 1 064 nm. The EO coefficients 733 of the polymer layer in the EO modulator were determined to be 2. 182 pm/V （poling voltage of 3.6 kV, 205 ℃） and 3. 107 pm/V （poling voltage of 3.8 kV, 210 ℃） at 1064 nm by an attenuated-total-reflection （ATR） method.

A High-Performance Silicon Electro-Optic Phase Modulator with a Triple MOS Capacitor

We propose and analyze a novel Si-based electro-optic modulator with an improved metal-oxide-semiconductor （MOS） capacitor configuration integrated into silicon-on-insulator （SOl）. Three gate-oxide layers embedded in the silicon waveguide constitute a triple MOS capacitor structure, which boosts the modulation efficiency compared with a single MOS capacitor. The simulation results demonstrate that the Vπ Lπ product is 2. 4V · cm. The rise time and fall time of the proposed device are calculated to be 80 and 40ps from the transient response curve, respectively,indicating a bandwidth of 8GHz. The phase shift efficiency and bandwidth can be enhanced by rib width scaling.

基于iSIGHT平台的主轴箱多目标优化设计

针对工程实际中复杂的多目标优化设计问题,常遇到性能目标与设计变量之间不具有显式的函数关系式,难以直接运用优化方法进行设计计算,因此提出基于i SIGHT平台的多目标集成优化设计方法。以主轴箱多目标优化设计问题为例,在i SIGHT平台上集成ANSYS软件并进行建模和分析,采用响应面法构建近似模型,利用邻域培植遗传算法获得多目标优化问题的Pareto最优解集,根据工程实际的不同需求,从中选出最合适的优化方案。

The Influences of the "Eight Sights" Culture on Modern Landscape Design

The cultural details and characteristics of 'Eight sights',which were existent but ignored,were found out through the introduction of the origin and the development of 'Eight sights'.The influences of the 'Eight sights' on modern landscape design were summarized,reflecting the regional and cultural characteristics.The practical significance of re-examining the 'Eight sights' for the development of our garden landscape was pointed out.

INERTIAL INTEGRATED SYSTEM OF NORTH SEEKING/SIGHT STABILIZING ON VEHICLE

A brand new method of automatic north seeking/sight stabilizing is introduced for usage in land fighting vehicles such as tank, etc. Some inertial devices are installed additionally on the platform along with relative control circuits to make its function of North seeking possible. Double position calculation is adopted in this method, and by alignment at two sites the azimuth angle can be figured out. Also the orientation and the horizontal shifts of the gyro are simultaneously measured and compensated so as to improve the accuracy of north seeking. The system can automatically seek north when the vehicle is immobile. And the time consumption is no more than 5.5 min. Besides, the system can keep azimuth angle and provide tilt angle and pitch angle of the vehicle.

基于iSIGHT集成技术的某重卡双轴转向机构多目标优化

针对东风某重卡汽车在使用中存在的轮胎异常磨损问题,利用ADAMS/View对双轴转向机构进行建模与运动学仿真。基于多学科设计优化(MDO)软件i SIGHT,实现ADAMS/View运动学仿真集成,并建立机构优化分析流程。采用正交数组DOE分析法和NSGA-II遗传算法实现了该双轴转向机构的多目标优化。优化结果表明:优化后各车轮转角误差大大减小,有效解决了车轮异常磨损问题。

基于iSIGHT平台的剖面几何参数对剖面性能的影响

为提高水翼抗空化性能,设计出具有较好空泡性能的翼型剖面,基于i SIGHT优化平台,集成翼剖面水动力性能的面元法理论预报程序,采用试验设计方法(DOE)构建剖面几何参数对翼剖面性能的响应面模型,分析剖面各几何参数对剖面空泡性能的影响。结果表明,增大剖面的最大拱度,最大厚度向导缘移动,最大拱度向尾缘移动以及减小攻角均有利于提高剖面的水动力性能;增加剖面的最大厚度能改善剖面的空泡性能,但剖面最大厚度一般根据剖面强度要求确定。

基于ISIGHT圆柱绕流的换热强化与减阻优化设计

圆柱绕流在工程应用中十分普遍,大到海洋结构物,小到微型换热器均有其身影,其中控制圆柱的排布对主圆柱的最终性能有着举足轻重的影响。为研究圆柱绕流系统的换热强度及减阻性能,本文利用ISIGHT优化平台强大的集成能力,实现利用ISIGHT驱动Gambit,Fluent软件并寻求最优参数组合的设计流程。研究发现,在Re=200时,与单圆柱系统相比,通过合理布置控制圆柱的方位参数(间隙率L/D=2,夹角degree=30°时),在提高换热性能的同时,还能减小圆柱阻力的优良结构。全程采用参数化设计,自动化寻优,提高了设计效率,为圆柱绕流提供了一个新的优化思路。