Damping oscillations in a wire bending process

This paper presents an approach to modify CAD/CAM generated motion profiles for wire bending machines, in order to damp wire oscillations without decreasing machine throughput. Two different methodologies are presented, both leveraging on a simple and easily identifiable model of wire oscillations, the first one based on a filtering approach, the second one on an optimisation approach. The two methodologies are both characterised by a low computational complexity, allowing them to be integrated directly in the bending machine user interface, and can rely on a standard camera to identify wire oscillation parameters. A thorough experimental validation of the approaches is also presented, showing promising results in damping oscillations with wires of different materials.     

基于ADAMS和MATLAB的双足机器人运动轨迹规划和控制的联合仿真

相比ADAMS仿真的不稳定性,利用ADAMS和MATLAB联合仿真对双足机器人运动轨迹规划和控制设计的可靠性及高效性进行了研究。首先绘制双足机器人三维参数模型进行逆运动学分析,验证其合理性后导入ADAMS中添加约束,进行动力学仿真。基于此,在MATLAB中使用多项式插值法完成模型的步态规划。最后利用Simulink试验台建立控制系统的框图,由ADAMS输入关节角之后控制台输出关节的驱动力矩,完成双足机器人ADAMS和MATLAB的联合仿真。仿真结果显示,联合仿真相较于ADAMS仿真的波动性所获得的数据更加稳定,此法高效可行,可作为下一步设计双足机器人的控制系统电机选型的重要理论依据。     

两栖装甲车辆由陆入水过程中车体稳定性分析

对两栖装甲车辆水动力学模型的构建以及基于水上航行耐波稳定性的横摇运动进行了探索。首先建立了两栖装甲车辆由陆入水的动力学模型,并进行了仿真分析；而后将模型试验与融入遗传算法的系统辨识思想相结合,构建了对于两栖装甲车辆摇荡运动的辨别模型；最后通过对车辆在水上的横摇运动试验设计及侧体方案布置,对辨别模型的应用效果进行了验证。通过研究发现,水动力学模型能够对两栖装甲车辆由陆入水时的车体稳定性情况进行准确描述,基于遗传算法的系统辨识方法能够分段辨识两栖装甲车辆的横摇运动,为车辆水上航行稳定性的研究提供了借鉴。     

华南植物园藤本植物专类园规划设计

专类园是一种强调专类植物收集、展示和植物造 景的园林形式，在植物园建设中具有重要地位。藤本植物因 其独特的观赏特征、生长习性及生态效应，近年已成为城市 园林绿化的重要造景材料。在分析华南植物园藤本植物专类 园建设背景、园址概况的基础上，结合其功能定位，提出了 科学性、功能性、地域性、艺术性及以人为本的规划原则； 确定了“一轴、三线、三点、五片区”的总体规划布局。在 文化线的园林构图及造景上，重点阐述了三大主题景观节 点——帷幄疏影、西关居、文昌亭的设计理念及其园林建筑 风格，探讨了岭南传统建筑、小品及文化在构建地域特色园 林景观中的作用；在植物线的园林造景上，简介了各景区的 植物布置方式及组景模式；在科普旅游线的组织上，介绍了 园区的园林小品造景意境及科普设施布置形式，以期为中国 藤本植物专类园建设提供参考。     

Using Exploratory Scenarios in Planning Practice

Abstract

Problem, research strategy, and findings: Despite growing interest by practitioners in using exploratory scenarios within urban planning practice, there are few detailed guidelines for how to do this. Through the discussion of five case examples, we illustrate different approaches to linking exploratory scenarios to different planning contexts. We conclude by observing that to directly inform a plan, regardless of the specific approach taken, exploratory scenarios in urban planning must incorporate stakeholder values and not only rely on expert judgment and analysis.

Takeaway for practice: Exploratory scenarios are effective for analyzing uncertainty within a planning process. However, exploratory scenarios can be incorporated into planning practice in different ways, ranging from workshops among experts that aim to cultivate general learning to complex projects that result in highly detailed scenarios and recommendations for plans. Practitioners can draw on the cases we present to inspire planning methods for particular projects, taking into account specific contexts and goals.     

城市低碳群体建筑外部边缘空间规划仿真研究

针对当前空间规划方法存在的计算时间长、规划成本高等问题,提出一种基于蚁群算法的低碳群体建筑外部边缘空间规划方法。依据城市低碳群体建筑外部边缘空间的模糊特性,引入模糊集合理论对建筑外部边缘空间进行理解和建筑外部边缘空间模糊矩阵的构建,对边缘空间进行划分和限定。结合建筑外部边缘空间的特性和具体关系模式进行空间层次划分,计算空间属性权重,以此确立空间规划目标,根据空间规划目标函数构建空间规划模型,设定求解空间规划模型的蚁群算法信息素更新方式,依据个体信息素转移概率指导个体进行模型最优解搜索。实验结果表明,所提方法与传统的空间规划方法相比,有效减少了计算时间,降低了规划成本。     

Performance evaluation of two-worker operations in a worker-to-cell order assorting system

This paper studies an order assorting system (OAS) composed of multiple-parallel order assorting aisles (OAAs) in a retailer’s order fulfillment center. We evaluate two worker-assignment policies for a worker-to-part OAA: a dedicated-assignment policy and a shared-assignment policy. Our analytical models evaluate the mean value and variance of worker process time including assorting time, walk time, empty walk time, and blocking time when single-line products arrive randomly. From the worker process time, we identify the system flow time of product lines per each worker-assignment policy using G/G/1 and G/G/2 queuing models. We find that the shared-assignment policy performs better compared to the dedicated-assignment policy in spite of workers’ productivity losses incurred by blocking delays over high sort probability, slow walk speed, and high magnitude and variations of inter-arrival times. At the worker-centric break-even point of worker process time, where worker process time suggests selecting either policy, system flow time always suggests selecting the shared-assignment policy.     

基于粒子群优化算法的五自由度机械臂轨迹规划

为了让机械臂的工作时间达到最优,以自主研发的抛光机器人样机为研究对象,针对手表表壳表耳部分的抛光过程,提出PSO算法对五自由度机械臂轨迹规划进行优化,并通过MATLAB软件进行机械臂的仿真与分析。仿真结果表明,基于PSO算法的轨迹规划使机械臂在工作过程中加加速度不会产生突变,运动轨迹精度高,机械臂工作时间达到最优。     

基于压迫感分析的城市高架桥美学设计研究

为解决城市高架桥对其地面道路及周边地块产生的压迫感这一问题,并且指导城市高架桥的设计和规划,使之在满足交通功能和用地要求的同时兼顾美学的考虑,研究根据压迫感主要来源为建筑对视野限制的推论,分析了压迫感的主要影响因素为建筑在视野中形成的视角,讨论了现有立体角理论模型的适用性,并且结合城市高架桥视角的特点,将立体角理论模型简化为平面视角理论模型以增强其适用性。建立了桥梁的结构尺寸与影响点的视角的关系式,以压迫感接受率表征压迫感的大小,再根据调查统计数据拟合,确定视角与压迫感接受率的关系曲线,从而得到桥梁的结构尺寸与影响点压迫感接受率的关系式。在规划和设计时,可根据该公式合理确定桥梁下地面道路的红线宽度或两侧地块的退红净距。