可重构模块机器人倾翻稳定性研究

介绍了一种可重构模块机器人,它可以通过构形的变化来提高系统的稳定性和抗倾翻能力.该机器人由3个模块组成,采用履带驱动,具有直线、三角、并排3种对称构形.在对移动机器人的倾翻因素和倾翻对策等问题进行分析的基础上,提出稳定锥方法,用倾翻性能指数对移动机器人的静、动态稳定性进行综合判定.讨论了变形机器人3种对称构形在仰俯、偏转、倾斜等干扰组合作用下的倾翻性能指数和综合稳定性,并进行了仿真实验和非结构环境实验.

链式可重构机器人单模块结构设计与运动实验

提出了一种新型模块化链式移动机器人机构,它具有可重构、自动变形的特点。单个标准模块主要由中间通孔式连接手臂、履带驱动链传动装置、模块偏转锥齿轮传动装置、模块俯仰链传动装置、连接柄等组成。模块间由偏转关节、连接柄、连接臂和仰俯关节进行连接组合。为提高单个模块的机动性和实现运动自主功能,对标准模块进行了适当改进,单模块机器人采用了履带、轮、臂、腿组合的移动机构,具有三维空间的运动能力。最后对单模块机器人样机在垂直壁障碍、平地支腿、平地转弯、斜坡、楼梯等情况下的运动能力进行了实验,为进一步实现多模块机器人的自重构和环境应用打下了基础。

一种并联机床的位置、速度和加速度逆解

本文针对一种混合结构的并联机器人机床,采用串并联运动学等效的方法,进行了运动学研究,推导了系统的位移、速度和加速度逆解的表达式,这可用于机床在加工时的运动规划及插补算法的实现。本文还进行了运动学仿真研究,机床的实际加工操作应用的结果表明,推导的运动学算法的正确性。

微型ROV控制装置及控制方法

介绍了一种基于嵌入式ARM9技术的微型ROV的控制装置及控制方法。该装置可以同时进行两通道串行通讯,实现微型ROV的视频信号、潜水深度、艏向角度、纵倾角度、横摇角度、电子舱温度等数据的采集和与上位机的通讯传输;该装置可以采集16路模拟量信号和12路数字量信号,输出4路模拟量信号和12路TTL电平信号,实现推进器、水下灯、水下摄像机、云台等ROV功能器件的驱动。该装置具有通讯能力强、集成度高、功耗低等特点,可以满足微型ROV所有的常用功能要求。

水下滑翔机器人运动机理仿真与实验

对水下滑翔机器人SEA-WING的定常滑翔运动和空间定常螺旋回转运动进行机理分析,针对其特定水动力系数进行仿真,得出其运动机理特性。在此基础上,通过湖试实验数据对仿真结果进行验证,认为对于定常滑翔运动,以约36°航迹角滑行可得到最大水平速度;在相同航迹角航行情况下,水平方向速度随净浮力的增大而增大。对于定常回转运动,回转半径由载体的质量、俯仰角、水动力参数、横滚角确定。在质量和俯仰角保持不变条件下,横滚角对回转半径的影响较明显,系统的回转半径可以通过控制横滚角来实现的。

水下滑翔机器人运动分析与载体设计

水下滑翔机器人是一种新型水下机器人,具有噪声低、航行距离远、续航时间长、成本低等特点。分析了水下滑翔机器人的驱动机理和运动实现,给出了水下滑翔机器人典型运动的仿真结果,并以正在设计的一水下滑翔机试验样机为研究对象,描述了样机的整体结构布局,详细研究了浮力调节机构、俯仰调节机构和横滚调节机构的实现方法,并就样机中各执行机构的设计实现进行了论述。

水下滑翔机器人运动调节机构设计与运动性能分析

描述了水下滑翔机器人3个运动调节机构的设计,即浮力调节机构、俯仰调节机构和横滚调节机构,分析了运动调节机构与运动之间的关系.提出了采用CFX水动力计算软件分析水下滑翔机器人运动性能的方法.根据CFX计算结果,用最小二乘法参数辨识方法辨识出定常滑翔运动的水动力参数.简化了空间螺旋回转运动过程,通过CFX水动力计算方法进行回转特性分析,估算回转半径.

“CR-02”AUV无动力下潜运动预报

本文针对“CR- 0 2”AUV海试前的无动力下潜运动进行了预报 .该文在建立 AUV无动力下潜运动数学模型基础上 ,研究分析了其稳态运动的特点 ,提出了下潜深度变化率和纵倾角是描述 AUV无动力下潜运动的重要参数 ,并获得了它们的解析表达式 ,无需使用计算机 ,就能快速、方便、准确地确定上述参数 ,并选取适当的下潜压载 ,以提高下潜速度 ,减少下潜时间 ,该方法具实际应用价值 .

超短基线定位系统在ROV动力定位中应用的可行性研究

以英国 Sonardyne公司的超短基线 (Ultra- Short Base L ine)为研究对象 ,研究了该系统在各种情况下的重复定位精度 ,以及将该系统应用于水下机器人动力定位的可能性 .实验结果表明 ,即使存在姿态偏差 ,如果通过姿态传感器进行动态补偿 ,该系统仍能获得很好的重复定位精度 ,可以满足水下机器人动力定位的需要

小襟翼对自治式水下机器人潜浮运动的影响

无动力大纵倾角的下潜和上浮方式对自治式水下机器人具有很大的意义．但是这种潜浮方式却无法满足自治式水下机器人潜浮位置范围及航向控制的要求．采用在稳定翼上加装小襟翼的方法，即可以解决这一难题．本文介绍了小襟翼对自治式水下机器人无动力潜浮运动轨迹的影响，并通过自治式水下机器人的运动方程，结合“ＣＲ－０１”６０００ｍ自治式水下机器人的深海试验结果，对这一影响作了定性地分析．为通过试验找出最佳小襟翼提供了理论基础

遥控作业移动机器人环境建模方法研究

本文介绍了用于遥控机器人作业虚拟环境生成的建模方法．重点研究了基于人机交互的双目立体视觉和多视点建模方法，以克服视觉自动建模方法计算复杂、鲁棒性差的缺点．给出了环境建模的实验系统和实验结果。

计算机离线签名鉴定系统研究

介绍了基于VC++开发的离线签名笔迹计算机鉴定系统,能够较好地实现签名笔迹图像多种处理效果,以满足特征提取的不同需要。他可以从复杂签名图像背景下提取出不同颜色签名笔迹,具有方便、快捷、失真小的特点。通过将笔划宽度斜度特征α加入系统进行鉴别,可有效降低识别的错误率,获得了相对较好的鉴别效果。

改进叠前深度偏移的计算效率＆叠前高分辨率成像

An high-resolution prestack imaging technique of seismic data is developed in this thesis. By using this technique, the reflected coefficients of sheet sands can be gained in order to understand and identify thin oil reservoirs. One-way wave equation based migration methods can more accurately model seismic wave propagation effect such as multi-arrivals and obtain almost correct reflected energy in the presence of complex inhomogeneous media, and therefore, achieve more superiorities in imaging complex structure. So it is a good choice to apply the proposed high-resolution imaging to the presatck depth migration gathers. But one of the main shorting of one-way wave equation based migration methods is the low computational efficiency, thus the improvement on computational efficiency is first carried out. The method to improve the computational efficiency of prestack depth migration is first presented in this thesis, that is frequency-dependent varying-step depth exploration scheme plus a table-driven, one-point wavefield interpolation technology for wave equation based migration methods; The frequency-dependent varying-step depth exploration scheme reduces the computational cost of wavefield depth extrapolation, and the a table-driven, one-point wavefield interpolation technology reconstructs the extrapolated wavefield with an equal, desired vertical step with high computational efficiency. The proposed varying-step depth extrapolation plus one-point interpolation scheme results in 2/3 reduction in computational cost when compared to the equal-step depth extrapolation of wavefield, but gives the almost same imaging. The frequency-dependent varying-step depth exploration scheme is presented in theory by using the optimum split-step Fourier. But the proposed scheme can also be used by other wave equation based migration methods of the frequency domain. The proposed method is demonstrated by using impulse response, 2-D Marmousi dataset, 3-D salt dataset and the 3-D field dataset. A method of high-resolution prestack imaging is presented in the 2nd part of this thesis. The seismic interference method to solve the relative reflected coefficients is presented. The high-resolution imaging is obtained by introducing a sparseness- constrained least-square inversion into the reflected coefficient imaging. Gaussian regularization is first imposed and a smoothed solution is obtained by solving equation derived from the least-square inversion. Then the Cauchy regularization is introducing to the least-square inversion , the sparse solution of relative reflected coefficients can be obtained, that is high-resolution solution. The proposed scheme can be used together with other prestack imaging if the higher resolution is needed in a target zone. The seismic interference method in theory and the solution to sparseness-constrained least-square inversion are presented. The proposed method is demonstrated by synthetic examples and filed data.

Fourier有限差分法深度偏移与正演模拟

With the development of seismic exploration, the target becomes more and more complex, which leads to a higher demand for the accuracy and efficiency in 3D exploration. Fourier finite-difference (FFD) method is one of the most valuable methods in complex structure exploration, which keeps the ability of finite-differenc method in dealing with laterally varing media and inherits the predominance of the phase-screen method in stablility and efficiency. In this thesis, the accuracy of the FFD operator is highly improved by using simulated annealing algorithm. This method takes the extrapolation step and band width into account, which is more suitable to various band width and discrete scale than the commonely-used optimized method based on velocity contrast alone. In this thesis, the FFD method is extended to viscoacoustic modeling. Based on one-way wave equation, the presented method is implemented in frequency domain; thus, it is more efficient than two-way methods, and is more convenient than time domain methods in handling attenuation and dispersion effects. The proposed method can handle large velocity contrast and has a high efficiency, which is helpful to further research on earth absorption and seismic resolution. Starting from the frequency dispersion of the acoustic VTI wave equation, this thesis extends the FFD migration method to the acoustic VTI media. Compared with the convetional FFD method, the presented method has a similar computational efficiency, and keeps the abilities of dealing with large velocity contrasts and steep dips. The numerical experiments based on the SEG salt model show that the presented method is a practical migration method for complex acoustical VTI media, because it can handle both large velocity contrasts and large anisotropy variations, and its accuracy is relatively high even in strong anisotropic media. In 3D case, the two-way splitting technique of FFD operator causes artificial azimuthal anisotropy. These artifacts become apparent with increasing dip angles and velocity contrasts, which prevent the application of the FFD method in 3D complex media. The current methods proposed to reduce the azimuthal anisotropy significantly increase the computational cost. In this thesis, the alternating-direction-implicit plus interpolation scheme is incorporated into the 3D FFD method to reduce the azimuthal anisotropy. By subtly utilizing the Fourier based scheme of the FFD method, the improved fast algorithm takes approximately no extra computation time. The resulting operator keeps both the accuracy and the efficiency of the FFD method, which is helpful to the inhancements of both the accuracy and the efficiency for prestack depth migration. The general comparison is presented between the FFD operator and the generalized-screen operator, which is valuable to choose the suitable method in practice. The percentage relative error curves and migration impulse responses show that the generalized-screen operator is much sensiutive to the velocity contrasts than the FFD operator. The FFD operator can handle various velocity contrasts, while the generalized-screen operator can only handle some range of the velocity contrasts. Both in large and weak velocity contrasts, the higher order term of the generalized-screen operator has little effect on improving accuracy. The FFD operator is more suitable to large velocity contrasts, while the generalized-screen operator is more suitable to middle velocity contrasts. Both the one-way implicit finite-difference migration and the two-way explicit finite-differenc modeling have been implemented, and then they are compared with the corresponding FFD methods respectively. This work gives a reference to the choosen of proper method. The FFD migration is illustrated to be more attractive in accuracy, efficiency and frequency dispertion than the widely-used implicit finite-difference migration. The FFD modeling can handle relatively coarse grids than the commonly-used explicit finite-differenc modeling, thus it is much faster in 3D modeling, especially for large-scale complex media.

基于显式分形插值的高保真地震数据重建方法研究

Based on the fractal theories, contractive mapping principles as well as the fixed point theory, by means of affine transform, this dissertation develops a novel Explicit Fractal Interpolation Function（EFIF）which can be used to reconstruct the seismic data with high fidelity and precision. Spatial trace interpolation is one of the important issues in seismic data processing. Under the ideal circumstances, seismic data should be sampled with a uniform spatial coverage. However, practical constraints such as the complex surface conditions indicate that the sampling density may be sparse or for other reasons some traces may be lost. The wide spacing between receivers can result in sparse sampling along traverse lines, thus result in a spatial aliasing of short-wavelength features. Hence, the method of interpolation is of very importance. It not only needs to make the amplitude information obvious but the phase information, especially that of the point that the phase changes acutely. Many people put forward several interpolation methods, yet this dissertation focuses attention on a special class of fractal interpolation function, referred to as explicit fractal interpolation function to improve the accuracy of the interpolation reconstruction and to make the local information obvious. The traditional fractal interpolation method mainly based on the randomly Fractional Brown Motion (FBM) model, furthermore, the vertical scaling factor which plays a critical role in the implementation of fractal interpolation is assigned the same value during the whole interpolating process, so it can not make the local information obvious. In addition, the maximal defect of the traditional fractal interpolation method is that it cannot obtain the function values on each interpolating nodes, thereby it cannot analyze the node error quantitatively and cannot evaluate the feasibility of this method. Detailed discussions about the applications of fractal interpolation in seismology have not been given by the pioneers, let alone the interpolating processing of the single trace seismogram. On the basis of the previous work and fractal theory this dissertation discusses the fractal interpolation thoroughly and the stability of this special kind of interpolating function is discussed, at the same time the explicit presentation of the vertical scaling factor which controls the precision of the interpolation has been proposed. This novel method develops the traditional fractal interpolation method and converts the fractal interpolation with random algorithms into the interpolation with determined algorithms. The data structure of binary tree method has been applied during the process of interpolation, and it avoids the process of iteration that is inevitable in traditional fractal interpolation and improves the computation efficiency. To illustrate the validity of the novel method, this dissertation develops several theoretical models and synthesizes the common shot gathers and seismograms and reconstructs the traces that were erased from the initial section using the explicit fractal interpolation method. In order to compare the differences between the theoretical traces that were erased in the initial section and the resulting traces after reconstruction on waveform and amplitudes quantitatively, each missing traces are reconstructed and the residuals are analyzed. The numerical experiments demonstrate that the novel fractal interpolation method is not only applicable to reconstruct the seismograms with small offset but to the seismograms with large offset. The seismograms reconstructed by explicit fractal interpolation method resemble the original ones well. The waveform of the missing traces could be estimated very well and also the amplitudes of the interpolated traces are a good approximation of the original ones. The high precision and computational efficiency of the explicit fractal interpolation make it a useful tool to reconstruct the seismic data; it can not only make the local information obvious but preserve the overall characteristics of the object investigated. To illustrate the influence of the explicit fractal interpolation method to the accuracy of the imaging of the structure in the earth’s interior, this dissertation applies the method mentioned above to the reverse-time migration. The imaging sections obtained by using the fractal interpolated reflected data resemble the original ones very well. The numerical experiments demonstrate that even with the sparse sampling we can still obtain the high accurate imaging of the earth’s interior’s structure by means of the explicit fractal interpolation method. So we can obtain the imaging results of the earth’s interior with fine quality by using relatively small number of seismic stations. With the fractal interpolation method we will improve the efficiency and the accuracy of the reverse-time migration under economic conditions. To verify the application effect to real data of the method presented in this paper, we tested the method by using the real data provided by the Broadband Seismic Array Laboratory, IGGCAS. The results demonstrate that the accuracy of explicit fractal interpolation is still very high even with the real data with large epicenter and large offset. The amplitudes and the phase of the reconstructed station data resemble the original ones that were erased in the initial section very well. Altogether, the novel fractal interpolation function provides a new and useful tool to reconstruct the seismic data with high precision and efficiency, and presents an alternative to image the deep structure of the earth accurately.