【作者】 徐从启；

【导师】 戴一帆；

【作者基本信息】 国防科学技术大学 ， 机械工程， 2010， 博士

【摘要】 内径为15～20 mm的薄壁倒“U”型传热管道广泛应用于核反应堆蒸发器中,长期运行后,容易发生因腐蚀、疲劳破坏或破损而引起泄漏事故等。因此,其监测、诊断、清理和维护就成为保障核反应堆系统安全、畅通和高效运营的关键。然而由于该类管道结构复杂,内部空间狭小,所处环境对人体有害,检修和维护十分困难。因此,开展适应在该类特殊管道环境下工作的新型微小管道机器人设计和研究,实现对核反应堆蒸发器传热管道的无损检测,具有非常重要的意义。基于对核反应堆蒸发器传热管道无损检测的迫切需求,本论文依托“十一五”部委预研项目和国家863计划资助项目,开展新型微小管道机器人设计和研究,力争突破“微小型化、大牵引力、快速、长距离运动”的管道机器人关键共性技术。本文系统深入地开展了新型机器人本体结构设计、设计理论建模、运动稳定性分析和多目标优化等关键问题研究。论文的研究工作主要包括以下几个部分:1.设计了一种新型具有自主锁止功能的蠕动式微小管道机器人。针对微小管道机器人结构设计中的微小型化、管径适应性及弯管通过性等问题,在比较分析已有驱动方案及移动方式优缺点的基础上,提出了自主锁止蠕动式方案,开展了机器人本体结构设计及优化研究,提出了自调节支撑机构、柔性保持机构和软轴驱动机构的创新设计。虚拟样机仿真表明,所设计的微小管道机器人实现了与管壁间的自主锁止,改善了机器人的管径适应性,有效解决了刚性支撑问题和弯管通过性问题。2.系统研究了自主锁止蠕动式微小管道机器人的力学特性问题。针对机器人的管径适应能力,基于力学平衡和虚位移原理,分析了自调节支撑机构的力学性能;分析了机器人的驱动特性,建立了封闭力、牵引力及爬坡能力的数学模型;利用积分原理和运动合成法,建立了机器人管内运动阻力的数学模型;讨论了管内“自转”问题,分析了机器人产生“自转”的机理,提出了支撑轮和保持轮的球形设计方案,有效抑制了“自转”的发生;建立了机器人传动系统的机电动力学方程。上述建立的数学模型及取得的结论,为微小管道机器人的结构设计及优化提供了理论依据。3.深入研究了摩擦接触约束下的微小管道机器人运动稳定性问题。针对机器人的管内受限运动,综合考虑滑动摩擦和滚动摩擦接触,建立了基于完整系统第一类拉格朗日方程的受限刚体动力学模型;利用线性互补理论,讨论了动力学方程解的存在性和唯一性问题;结合Kelvin接触模型,利用奇异摄动理论和Layapunov稳定性理论,给出了受限刚体稳定性的附加条件;对所设计的机器人在直管运动的稳定性情况进行了仿真,依据仿真结果提出了柔性保持机构设计方案,有效解决了微小管道机器人管内运动失稳问题。4.研究了基于遗传算法的微小管道机器人多目标优化问题。根据机器人的运动特点,建立了速度计算模型;利用能量平衡关系,采用最小二乘法和极值原理,建立了机器人传动系统的功耗模型;在此基础上,建立了以机器人结构尺寸为约束变量,以牵引力、运动速度及系统功耗为目标函数的多目标优化模型;利用遗传算法对微小管道机器人多目标优化模型进行寻优求解。优化结果表明,机器人的牵引力理论值为11.47 N,运动速度可达12.7 mm/s,较好地实现了预期目标。5.成功研制了两代试验样机,开发了运动控制箱,搭建了模拟管道试验系统,开展了相关试验研究。试验结果表明,经优化改进后的第二代机器人样机可平稳运行于内径为15～20 mm的管道,可通过曲率半径不小于80 mm的弯管,移动速度为8.7～12 mm/s,具有0～90o爬坡能力,可双向运动,最大牵引力约为9.95 N,载重自重比可达6.77:1,较好地实现了管道机器人“微小型化、大牵引力、快速、长距离运动”的设计目标。更多还原

【Abstract】 Thin-wall inverted "U" type heat transfer pipelines with inner diameters ranging from 15~20 mm, are extensively used in nuclear reactor evaporators. After a long running, they are prone to corrosion, fatigue failure, or damage to cause leakage accidents, etc. Therefore, it has become a key to monitor, diagnose, clean and maintain for the sake of safety, smoothness and efficient operations of the nuclear reactor system. However, due to their complex structure, constrained internal space, and poisonous environment, repair and maintenance of the pipelines are very difficult. So it is very important to develop a new type of micro in-pipe robot applicable to such special cases, to realize non-destructive testing on the heat transfer pipelines in nuclear reactor evaporators.Based on the urgent need of automatic detection of micro heat transfer pipelines in nuclear reactor evaporators, this thesis carries out the design and research of a new type micro in-pipe robot supported by the "Eleventh Five-Year Plan" Ministry Pre-research Project and the Hi-Tech Research and Development Program (863) of China. Aiming at technological breakthrough of "microminiaturization, large traction, fast, long-distance movement" for in-pipe robot, this thesis is focused on the structure design, theoretical modeling, motion stability analysis and multi-objective optimization and other key issues of the robot. The research efforts mainly include the following points:1. A new type of creeping micro in-pipe robot with autonomous lockup function is designed. Aiming at the issues of microminiaturization, diameter adaptation and elbow trafficability, and based on the analysis of the advantages and disadvantages of the existing driving schemes, an autonomous lockup creeping micro in-pipe robot is proposed. Then the body structure is designed and optimized. As a result, innovative design of self-regulating supporting mechanism, flexible holding mechanism and flexible-shaft driving mechanism is presented. The virtual prototype simulation shows that the optimized micro in-pipe robot possesses the advantages of autonomous lockup and improved diameter adaptability, and efficiently solves the problems of rigid braces and elbow trafficability.2. The mechanical characteristics of the micro in-pipe robot are researched systematically. Based on the principles of mechanical equilibrium and virtual displacement, the mechanical properties of self-regulating supporting mechanism are discussed in respect of diameter adaptability. Then the driving characteristics of the robot are analyzed, and mathematical models of closed-force, traction and climbing ability are established. As a result, the monotonically decreasing law of the traction changing with the diameter is discovered. Using integral theory and motion synthesis, the movement resistance and the "autorotation" problem are discussed. After the mechanism of robot’s "autorotation" analyzed, the spherical design of supporting and holding wheels is presented to efficiently restrain the "autorotation". At last, the mechatronics dynamic equations of the robot’s drive system are established. The above-mentioned established mathematical models and the conclusions provide theoretical basis for structure design and optimization of the micro in-pipe robot.3. Motion stability of micro in-pipe robot with frictional contacts is studied in depth. With sliding and rolling friction contacts considered, the limited rigid body dynamics model is established in respect of the robot’s restricted movement, which is based on the first Lagrangian equation for holonomic system. Using linear complementarity theory, the existence and uniqueness of dynamic equation is discussed. Combining Kelvin’s contact model, using singular perturbation and Layapunov’s stability theory, the additional conditions of stability of constrained rigid body are given. With the stability conditions of the robot movement in straight pipes simulated, the flexible holding mechanism is presented, which efficiently solves the instability problem of micro in-pipe robot moving in pipelines.4. Based on the genetic algorithm, the multi-objective optimization problem of micro in-pipe robot is studied. According to characteristics of the robot’s movement, the speed calculation model is established. Using energy balance, the least square method and extremum principle, the power model for the robot transmission system is established. On this basis, the multi-objective optimization model is established, where some sizes of the robot are taken as the variables, and traction, kinematic velocity and system power consumption are taken as the objective functions. Using genetic algorithm, optimization solution to the multi-objective model of the micro in-pipe robot is obtained. The results show that the theoretical value of robot’s traction is 11.47 N, with velocity of movement up to 12.7 mm/s, well conformed to the design specifications.5. Two-generation test prototypes and motion control box of the robot are developed successfully. Then the test system is established with experiments conducted. The experimental result shows that the optimized second-generation prototype can smoothly run in 15~20 mm diameter pipelines, pass the elbow with radius of curvature no less than 80 mm, move bidirectionally with a speed of 8.7~12 mm/s, climb the oblique pipelines angled 0~90o, and carry load about 9.95 N. And the load weight ratio is up to 6.77:1, which well meets the design goals of "microminiaturization, large traction, fast, long-distance movement" for the pipeline robot.更多还原