A high-efficiency planar micromixer with convection and diffusion mixing over a wide Reynolds number range

Over a wide Reynolds number range (0.1 ≤ Re ≤ 40), the new planar obstacle micromixer has been demonstrated over 85% mixing efficiency covering the mixing improvement in both convection-enhanced (higher Re flow) and diffusion-enhanced (lower Re flow) mechanisms. Mixing behavior between two operation windows was investigated by numerical simulations and experiments. For the adaptive design, numerical simulations and Taguchi method were used to study the effect of four geometrical factors on sensitivity of mixing. The factors are gap ratio (H/W), number of mixing units, baffle width (W _b) and chamber ratio (W _m /W). The degree of sensitivity using the Taguchi method can be ranked as: Gap ratio > Number of mixing units > Baffle width > Chamber ratio. Micromixer performance is greatly influenced by the gap ratio and Reynolds number. Beside the wide Reynolds number range, good mixing efficiency can be obtained at short distance of a mixing channel and relatively low-pressure drop. This micromixer had improved both complex fabrication process of multi-layer or 3D micromixers and low mixing efficiency of planar micromixer at Re < 100. The trend of the verified experimental results is in agreement with the simulate results.     

Seeking a path through the crowd: Robot navigation in unknown dynamic environments with moving obstacles based on an integrated environment representation

We present a novel algorithm for collision free navigation of a non-holonomic robot in unknown complex dynamic environments with moving obstacles. Our approach is based on an integrated representation of the information about the environment which does not require to separate obstacles and approximate their shapes by discs or polygons and is very easy to obtain in practice. Moreover, the proposed algorithm does not require any information on the obstacles’ velocities. Under our navigation algorithm, the robot efficiently seeks a short path through the crowd of moving or steady obstacles. A mathematically rigorous analysis of the proposed approach is provided. The performance of the algorithm is demonstrated via experiments with a real robot and extensive computer simulations.     

一种基于分离地面点的障碍物识别方法

Velodyne 64线雷达被广泛应用于自主车的环境感知功能中。为了在该雷达产生的大量数据中识别出障碍物信息,本文提出了一种新的基于分离地面点的障碍物识别算法。首先从原始数据集中提取出特征点集并建立地面模型;利用地面模型识别出地面点并将其从数据集中滤除;将地面点分离后的数据集投影至平面栅格中,并利用区域生长法聚类。该算法能够准确、高效地识别出障碍物。     

Prediction for vented explosions in chambers with multiple obstacles

The predictive ability between existing models on explosion venting, such as the NFPA, Molkov and Yao equations, was examined against experimental data of peak pressures obtained in various chambers with internal obstacles. The NFPA equation yielded the highest overpressures in most cases. The Molkov and Yao equations obtained much better agreement with experiments. However, the statistical diagnosis of the data showed an underprediction of the pressures. This is undesirable for designing calculations where some margin of safety is preferable. A new empirical model derived for characterising chambers with internal obstacles correlated well with the data. In addition the new equation was further validated against a dataset published from the literature and also gave a good correlation.     

基于改进RRT-Connect的空间操作臂避障路径规划研究

针对传统RRT-Connect算法应用于空间操作臂避障路径规划时,规划路径存在盲目性大、安全性差以及无效路径点多等问题,提出一种改进RRT-Connect算法。该算法结合RRT-Connect算法和Dijkstra算法,首先通过引入双树扩展目标点变更策略、极致贪婪策略以及新的碰撞检测方法提高传统RRT-Connect算法路径搜索效率和安全性;然后利用Dijkstra算法的优化特性去除规划路径中的多余无效节点,达到整体路径规划搜索速度快、路径长度短和安全性高等效果;最后通过MATLAB机器人工具箱进行算法对比仿真实验验证,实验结果表明了该方法的有效性和可行性。     

富钴结壳轮式集矿机越障性能研究

该文针对深海富钴结壳集矿机必须适应复杂恶劣地形和强的越障性能,提出一种四轮独立驱动的轮式钴结壳集矿机行走机构。通过对轮式集矿机越障机理的分析,研究了轮式集矿机通过陡坡、台阶和壕沟等典型地形的受力情况,并分析了集矿机重心位置与集矿机越障性能的关系。建立了基于ADAMS软件的集矿机虚拟样机模型和典型地面,对集矿机的典型地形越障过程进行了动力学仿真分析,仿真结果表明:轮式集矿机的最大爬坡角度不小于30,°最大可通过的台阶高度和壕沟宽度不小于车轮半径,具有很好的越障性能,是一种可行的钴结壳集矿机行走方式。     

小型轮履腿复合式机器人设计及运动特性分析

针对在室内外环境下对小型移动机器人的运动要求,综合轮式、履带式和腿式运动机构的优点,研制开发了一种多运动模式的小型轮履腿复合式移动机器人。该机器人可以进行轮式高速运动、履带或腿式越障等多种模式的运动。对其运动特性、越障性能、自动复位功能进行了详细的分析。采用的嵌入式控制系统保证了机器人功耗低、可靠性好、实时性高的控制要求。试验表明,这种移动机器人运动灵活,具有很好的环境适应性和较高的越障能力。     

肢体运动功能障碍的定量化客观检测与评定研究

本文报道采用现代计算机图象技术实现客观的定量化检测与评定的研究成果,提出了新的肢体运动障碍评分和评级方法,研制了相应的实用测评系统,并取得很好的实际应用效果。     

常州盘石水泥集团行政中心

常州盘石水泥集团行政中心办公楼设计因地制宜,注重建筑与总体环境之间的平衡与协调关系,运用现代设计理念和方法营造便捷高效、景观化的办公环境。     

智能移动机器人的多传感器控制避障研究

针对我们现实生活中未知的、时变的周围环境,提出了一种基于多传感器的自主移动机器人在多障碍物环境中智能避障的设计。利用自身安装的四探头一体防水超声波传感器、红外传感器为有效的环境感知提供障碍物的距离数值,采用核心芯片STM32F407处理多传感器获取到的距离数据,并将控制指令输入到执行单元。对其主控制电路、各个传感器接口的设计实现了移动机器人避障控制系统的硬件设计。通过对获得的多组传感器实验数值的分析以及对机器人样机的多次测试验证了其设计的可行性。