Throughput Optimization in Constant Travel‐Time Dual Gripper Robotic Cells with Parallel Machines

Constant travel‐time robotic cells with a single gripper robot and with one or more machines at each processing stage have been studied in the literature. By contrast, cells with a dual gripper robot, although more productive, have so far received scant attention, perhaps due to their inherent complexity. We consider the problem of scheduling operations in dual gripper robotic cells that produce identical parts. The objective is to find a cyclic sequence of robot moves that minimizes the long‐run average time to produce a part or, equivalently, maximizes the throughput. We provide a structural analysis of cells with one or more machines per processing stage to obtain first a lower bound on the throughput and, subsequently, an optimal solution under conditions that are common in practice. We illustrate our analysis on two cells implemented at a semiconductor equipment manufacturer and offer managerial insights for assessing the potential productivity gains from the use of dual gripper robots.     

Modified branching process for the reliability analysis of complex systems: Multiple-robot systems

Current design practice is usually to produce a safety system which meets a target level of performance that is deemed acceptable by the regulators. Safety systems are designed to prevent or alleviate the consequences of potentially hazardous events. In many modern industries the failure of such systems can lead to whole system breakdown. In reliability analysis of complex systems involving multiple components, it is assumed that the components have different failure rates with certain probabilities. This leads into extensive computational efforts involved in using the commonly employed generating function (GF) and the recursive algorithm to obtain reliability of systems consisting of a large number of components. Moreover, when the system failure results in fatalities it is desirable for the system to achieve an optimal rather than adequate level of performance given the limitations placed on available resources. This paper concerns with developing a modified branching process joint with generating function to handle reliability evaluation of a multi-robot complex system. The availability of the system is modeled to compute the failure probability of the whole system as a performance measure. The results help decision-makers in maintenance departments to analyze critical components of the system in different time periods to prevent system breakdowns.     

电弧喷涂自结合涂层的性能比较

热喷涂涂层与工件基体通常以机械方式结合,其结合强度与基体的表面粗化程度密切相关。一些材料经电弧喷涂后,与钢铁基体存在一定程度的冶金结合,它们可以牢固地结合在光滑洁净的工件表面上。自结合材料经常被用做过渡底层,来改善热喷涂涂层与工件基体的结合强度。本文分析了电弧喷涂QA19-2、Ni-A1复合丝、Ni-A1合金丝、Mo、Ti、Ni-Cr、B-01等材料的冶金结合效果及相关性能,介绍了上述几种材料的电弧喷涂工艺参数。     

壁面清洗机器人发展趋势浅析

本文综述了国内外壁面清洗机器人的研究概况 ,重点介绍了几种典型的壁面清洗机器人 ,据此对壁面清洗机器人向实用化方向发展进行了论述 ,指出了利用风扇使清洗机构吸附于壁面 ,并将行走与清洗机构相分离 ,这种设计思路的优越性     

焊接机器人轨迹规划的研究现状

为了提高焊接效率、改善焊接质量的实际生产需求,对焊接机器人空间轨迹规划的方法及研究现状进行了综述, 对关节轨迹规划法和笛卡尔轨迹规划法做出了比较,指出了轨迹规划中存在的问题即如何更便捷地实现最优轨迹规划 和多种最优算法的统一,认为空间轨迹同焊接工艺参数进行联合规划将是未来研究的重点和方向。     

固定电机驱动的平面关节型机器人无参数运动学标定

针对传统平面关节型机器人（简称SCARA）运动臂质量大的缺点,设计一种固定电机驱动的SCARA。为提高其 精度用无参数化标定的方法进行运动学标定,根据D-H方法,在空间坐标转换的基础上建立了该SCARA的数学模型, 得到杆件间相对位置关系;通过外部测量设备测出末端执行器的位姿,利用运动学正逆解解出实际位姿与理论位姿之间 驱动输入的差值,补偿到理论的输入中,得到补偿后的动平台位姿。通过计算机仿真表明该标定方法能极大提高末端执 行器的位置精度,证明了无参数化标定方法的有效性和可靠性。     

等离子喷涂Al2O3/TiO2陶瓷涂层修复热作模具应用

为了提高模具热疲劳抗力、延长模具使用寿命,采用等离子喷涂修复失效的热作模具,利用X射线衍射物相分析 和电子扫描显微镜观察等手段分析等离子喷涂制备纳米陶瓷涂层的形成机理。结果表明：利用Al203/Ti02陶瓷纳米材 料作为喂料可使热作模具表面显微硬度平均为HV 1 056.5,平均摩擦因数为0.74,各项物理指标均提高了。该方法达 到了热作模具的使用要求,具有一定的借鉴作用。     

认知科学美学与审美机器人

人类认知研究不仅表现在自然科学领域,还应表现在审美等人文领域。近十几年来,国内外的"认知科学与美学"研究都取得相当深刻的积极成果。特别是在中国,已经形成了相对完整的认知科学美学理论,对世界范围内的美学难题作出了科学化的新阐释,并提出了一些新的问题和假说。不过,认知科学还从来没有从美学的角度进行过专项研究及实验。如果相关实证研究得以进行,将最终地、彻底地揭示审美活动的本性,为审美实践提供具有可操作性的理论基础,还可以为审美机器人的开发提供可能。     

水稻种衣剂禾盛3号应用效果初探

水稻种衣剂禾盛 3号包衣后对种子室内发芽率有一定的抑制作用 ,浓度越大 ,发芽率降低越多 ,对秧苗素质和收获产量有一定的促进作用 ,特别是对苗期稻蓟马危害的防治 ,效果明显 ,达 79.7%～ 95 .8% ,使用浓度以药种质量比 1∶5 0或 1∶2 5的效果较好     

可食性保鲜膜应用现状分析

主要阐述了可食性保鲜膜的基本成膜原理,综合分析了其在食品工业中的现状,进一步提出了可食性保鲜膜的未来应用前景。