基于ROV援潜救生自主作业方法研究

利用ROV代替潜水员进行潜艇供排气管对接作业是援潜救生的发展趋势，其中供排气管对接技术是为失事艇员提供生命保障的关键技术。由于水下作业环境比较复杂以及水下作业难度大等特点，人工遥控ROV进行援潜对接供排空气管作业过程中，还停留在只是能够打开潜艇供排气系统花甲板盖的工作上，还没有实现对类似接通供排空气管精确作业的工作。受到海流、风浪、失事潜艇周围较大涡流、供排气管的拖曳阻力、水下可视条件以及高精度定位等因素的限制，作业任务越复杂，要求ROV系统上机械手精确定位精度越高，操纵的难度也越大，由人工操作很难实现。在现有ROV人工操作的基础上，使ROV系统具有自主作业功能，更能发挥其在对接空气管作业中的能力，提高作业效率，缩短救援时间，因此本文在现有ROV基础上扩展预编程自主控制驾驶功能模块即ROV-A系统，借助预编程技术ROV-A系统在对接空气管作业中的一些特殊任务时能够实现自主作业功能。 本文结合中国科学院沈阳自动化研究所水下机器人中心未来援潜救生关键技术研究内容，针对为失事潜艇接通空气管作业中的一些关键技术，开展基于具有自主作业能力的ROV-A系统自主作业方法研究，深入研究了具有自主作业能力ROV-A系统的运动规划与协调控制技术以及水下作业力控制技术，以实现高精度的机械手末端位置控制与期望力跟踪；针对潜艇供排气系统的已知结构研究了水下目标定位技术，为对接空气管的特定需求发展具有自主作业能力的水下作业技术提供理论依据。重点研究针对系统特点的运动规划与多性能指标实现归一化问题；研究基于系统动力学模型误差的系统位姿控制问题；研究基于阻抗力控制水下作业目标定位问题；在系统运动规划与控制研究的基础上，研究能实现机械手末端精确轨迹跟踪的控制策略问题以及力控制问题。本论文研究内容如下： （1）根据ROV-A系统特点，从描述系统的空间位置和姿态着手，研究了ROV-A系统的空间运动学与基于Kane方法的动力学，得出载体基座自由运动模式的系统空间运动数学模型，为论文后续研究工作奠定了基础。 （2）针对对接空气管作业中的一些高精度和复杂的作业，研究了系统作业时的运动规划问题。针对系统运动学冗余、作业规划约束性能指标多，例如机械手可操作性，关节限制，载体的姿态，避障等等，结合梯度投影法和最小范数伪逆矩阵法以及任务优先逆运动学方法，引入模糊控制技术，将模糊控制的定性知识表达与任务优先逆运动学算法相结合，以水下作业末端位置控制及轨迹跟踪为前提，对系统运动分配、关节限位、避免奇异有无海流下的系统性能优化等运动规划进行了研究，仿真证明运动规划算法的有效性。 （3）研究了基于动力学模型的系统基本控制问题。针对系统动力学模型的复杂性和不精确性，在基于载体输出反馈控制的基础上，设计了基于输出反馈自适应控制算法，通过自适应学习的方式直接逼近系统动力学方程状态量之间的非线性关系，在外界不停扰动下逐渐提高系统的控制精度；基于Lyapunov稳定性理论，证明了存在外界干扰和自适应逼近误差条件下ROV-A系统控制器的闭环稳定性；通过仿真实验验证控制系统的有效性，为系统的控制提供了一种新思路。同时在基于位置运动控制的基础上引入了力控制，通过对常规PID外环力控制器基础上的改进，在系统离线规划的前提下实现力与位置控制的解耦，通过仿真验证期望力的稳定跟踪。 （4）研究了基于ROV-A系统阻抗力控制的水下矩形围壁环境约束的位置定位方法。通过在对具有先验知识的矩形围壁环境约束的学习理解基础上，应用外部阻抗力控制环包容内部位置运动控制环的控制策略。利用力传感器的反馈信息变化确定系统末端执行器与约束环境的接触特征点，根据环境的先验知识推理出环境定位信息。通过计算机仿真实验验证了水下具有先验知识环境的定位方法和ROV-A系统的控制策略的有效性。仿真结果证明定位方法和控制策略是可行的。 （5）结合系统控制，分析了系统在为失事潜艇对接空气管作业中的恒定和时变两种期望力输入作业模式，提出了基于在线运动规划下外部力控制环包容内部位置环控制方法，利用ROV-A系统完成了为失事潜艇自主对接空气管中两个典型作业。介绍了整个控制方法的组成和执行过程，分析了综合控制策略，最后通过仿真实验分析了综合力控制方法的性能，包括恒力和时变期望力输入进行了深入研究。

Strength of Offshore Pipelines in Different Operation States and Analyzing Software

在近海管线的铺设、安装、使用过程中有多种作业状态：在位、悬跨、挖沟、提吊、铺管等。各种状态下管线的受力特点不同,加上管线结构、海况和海底土壤等因素又都很复杂,所以近海管线的强度分析难度大、内容多。分别采用解析方法、数值方法（有限元法、打靶法）和二者结合来解决理论上的（如几何非线性、动边界等）、实用性方面的难点。在理论分析的基础上,编制了符合产业部门工程师使用要求的近海管线强度分析软件。介绍了该软件进行力学分析时采用的理论以及软件界面。

1ps passively mode-locked laser operation of Na, Yb : CaF2 crystal

Diode-pumped passively mode-locked laser operation of Yb3+,Na+:CaF2 single crystal has been demonstrated for the first time. By using a SESAM ( semiconductor saturable mirror), simultaneous transform-limited 1-ps passively mode-locked pulses, with the repetition rate of 183MHz, were obtained under the self-Q-switched envelope induced by the laser medium. The average output power of 360mW was attained at 1047nm for 3.34W of absorbed power at 976nm, and the corresponding pulse peak power arrived at 27kW, indicating the promising application of Yb3+,Na+-codoped CaF2 crystals in achieving ultra-short pulses and high pulse peak power. (c) 2005 Optical Society of America.

MODIFIED DIRECT TWOS-COMPLEMENT PARALLEL ARRAY MULTIPLICATION ALGORITHM FOR COMPLEX MATRIX OPERATION

A direct twos-complement parallel array multiplication algorithm is introduced and modified for digital optical numerical computation. The modified version overcomes the problems encountered in the conventional optical twos-complement algorithm. In the array, all the summands are generated in parallel, and the relevant summands having the same weights are added simultaneously without carries, resulting in the product expressed in a mixed twos-complement system. In a two-stage array, complex multiplication is possible with using four real subarrays. Furthermore, with a three-stage array architecture, complex matrix operation is straightforwardly accomplished. In the experiment, parallel two-stage array complex multiplication with liquid-crystal panels is demonstrated.

MODIFIED ENGAGEMENT METHOD FOR MATRIX OPERATION

We describe a modified engagement method for matrix operation based on a two-dimensional crossed-ring interconnection network, Our method incorporates fewer steps than that reported by Bocker et al. [Appl. Opt. 22, 804 (1983)], and its performance is found to be the most efficient (minimum steps) in comparison with other systolic and/or engagement methods for matrix operation. Thus, it may be helpful for other optical and electronic implementations of matrix operations. One compact optoelectronic integrity approach for implementing the modified engagement method is briefly described. (C) 1995 Optical Society of America

Laser diode array side-pumped acousto-optic induced unidirectional operation Q-switched Nd : YAG slab ring laser

A laser-diode array (LDA) side-pumped Nd:YAG slab ring laser is described that incorporates a prism-shaped acousto-optic modulator to enforce unidirectional operation and Q-switching. When pumped by the maximum power of 50 W, Q-switched energies of 3.6 mJ and 50 ns duration, corresponding to a peak power of 72 kW, are obtained. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)01306-9].

Dynamic analysis of V-folded cavity for TEM00 operation of end-pumped solid-state laser

Based on graphic analysis design method of optical resonator, a simple design expression of V-folded cavity of end-pumped solid-state lasers with TEM00 operation is described, which satisfies two criterias of the resonator design. We give numerical simulation of spot size as a function of thermal focal length using this design approach whose advantages are validated experimentally.

High power single transverse mode operation of a tapered large-mode-area fiber laser

To get high output power with good beam quality, a tapered section is introduced to large-mode-area (LMA) Yb-doped fiber laser. Output characteristics of the fiber laser without tapered section and with tapered section are compared experimentally. When the launched pump power is 119.1 W, 77.9 W with M-2 3.08 and 56.4 W with M-2 1.14 can be obtained, respectively. The corresponding slope efficiencies are 71.8% and 54.1%, respectively. Although output power of the tapered fiber laser has 30.6% penalty, brightness of it is as much as 5.28 times of the fiber laser without tapered section. Moreover, spectra of them are measured. It is found that tapered section makes lasing wavelength of the fiber laser shorter. (c) 2007 Elsevier B.V. All rights reserved.

Characterization of diode-pumped laser operation of a novel Yb : GSO crystal

We report what is believed to be the first demonstration of the laser action of Yb3+ -doped Gd2SiO5 (Yb:GSO) crystal pumped by a 940-nm laser diode at room temperature. The threshold of laser generation is only 0.85 kW/cm(2), which is smaller than the theoretic threshold of Yb:YAG (1.54 kW/cm(2)). The laser wavelength is 1090 mn. With a 2.5% output coupler, the maximum output power is 415 mW under a pump power of 5 W. By using the SESAM, the Q-switched mode locking and CW mode-locked operations are demonstrated.

Room-temperature cw and pulsed operation of a diode-end-pumped Tm:YAP laser

We report the continuous-wave and acousto-optical Q-switched operation of a diode-end-pumped Tm:YAP laser. Continuous-wave output power of 3.5 W at 1.99 mu m was obtained under the absorbed pump power of 14 W. Under Q-switched laser operation, the average output power increased from 1.57 W to 2.0 W, with an absorbed pump power of 12.6 W, as the repetition rate increased from 1 kHz to 10 kHz. The maximum Q-switched pulse energy was 1.57 mJ with a repetition rate of 1 kHz. The minimum pulse width was measured to be about 80 ns, corresponding to a peak power of 19.6 kW.

Continuous-wave and Q-switched operation of a resonantly pumped Ho:YAlO3 laser

We demonstrated continuous-wave ( CW) and Q-switched operation of a room-temperature Ho: YAlO3 laser that is resonantly end-pumped by a diode-pumped Tm: YLF laser at 1.91 mu m. The CW Ho: YAlO3 laser generated 5.5 W of linearly polarized (E parallel to c) output at 2118 nm with beam quality factor of M-2 approximate to 1.1 for an incident pump power of 13.8 W, corresponding to optical-to-optical conversion efficiency of 40%. Up to 1-mJ energy per pulse at pulse repetition frequency (PRF) of 5 kHz, and the maximum average power of 5.3-W with FWHM pulse duration of 30.5 ns at 20 kHz were achieved in Q-switched mode. (C) 2008 Optical Society of America.

Diode-pumped continuous wave and Q-switched operation of a c-cut Tm,Ho:YAlO3 laser

We report on a diode-pumped, cryogenic and room temperature operation of a Tm,Ho:YAlO3 (c-cut) laser. In a temperature of 77 K, an optical-optical conversion efficiency of 27% and a slope efficiency of 29% were achieved with the maximum continuous-wave (CW) output power of 5.0 W at 2.13 mu m. Acousto-optic switched operation was performed at pulse repetition frequency (PRF) from 1 kHz to 10 kHz, the highest pulse energy of 3.3 mJ in a pulse duration of 40 ns was obtained. In room temperature (RT), the maximum CW power of Tm,Ho:YAlO3 laser was 160 mW with a slope efficiency of 11% corresponding to the absorbed pump power. (C) 2008 Optical Society of America.