超临速磨机中钢球和矿石的运动规律研究

介绍超临速磨机的结构 ,分析研究超临速磨机中矿石和钢球的运动规律 ,得出钢球在抛物运动阶段的轨迹方程和钢球对矿石的冲击速度公式。结果表明 ,钢球的抛物线运动轨迹主要决定于导向板下端点的位置 ,钢球对矿石的冲击速度决定于磨机的转速和直径     

虚拟界面的定义与描述

虚拟界面是建筑空间形式系统的一部分，是对该系统的补充，本文在完善空间界面分类的基础上，对虚拟界面作了定义，并通过阐明虚拟界面3种基本类型，详细描述了各种虚拟界面的构成特征，最后以此对密斯的巴塞罗那德国馆进行分析，验证了虚拟界面概念对解读空间的有效性。     

中关村软件园D-G1、D-G4地块景观设计

线的交织使中关村软件园D—G1地块产生了独特的景观结构，水线、晶体线和数据线体现了软件园特有的景观品质。合理的设计使D—G4地块得到充分的利用。     

膨胀石墨烟幕发生装置烟流颗粒运动规律与试验研究

针对膨胀石墨设计了一种简易烟幕发生装置,该装置利用烟火药燃烧时释放出的热量使可膨胀石墨膨化并分散于空中,形成膨胀石墨干扰烟幕。基于该装置建立了烟流颗粒(膨胀石墨颗粒)扩散规律的理论计算模型,对烟幕发生剂反应参数与烟流颗粒运动规律进行计算,得到烟流颗粒的运动方程。同时,对该装置进行了试验研究,并通过高速摄影记录烟流颗粒运动规律,试验结果表明烟流颗粒理论运动规律与试验结果相符,能够描述烟流颗粒的运动规律。     

采用PHOG融合特征和多类别Adaboost分类器的行为识别

为了解决类能量图易受人体运动时间和位置移动等因素影响而难以有效描述动作细节特征的问题,本文提出了一种基于类能量图金字塔梯度直方图(PHOG)融合特征和多类别Adaboost分类器的人体行为识别方法。该方法首先对经过躯体配准的运动人体目标轮廓图像构造平均运动能量图(AMEI)和增强的运动能量图(EMEI),分别提取其分层梯度方向直方图(PHOG)特征并进行串联融合,作为一种多层次的行为特征描述;然后使用基于查找表的LUT-Real Adaboost算法设计多类别分类器,实现图像中人体行为动作的识别。实验结果显示其在典型的人体动作数据集DHA上的正确识别率达97.6%,高于其它采用单一特征描述和SVM等分类器的方法。表明该方法将整体与局部特征相结合,可以有效描述不同尺度下的动作细节特征,增强了人体行为特征的描述能力,提高了识别性能。     

铸件多功能作业机器人多臂协调轨迹规划与仿真

以铸件多功能作业机器人的工作臂为研究对象,采用笛卡尔空间变量法对机器人铸件搬运过程进行轨迹规划。结合多臂协调的运动约束条件以及伪逆法,对机器人的4个工作臂关节运动进行优化,得到多机械臂协调运动的关节位置和速度变化曲线。由MATLAB软件仿真得到的运动参数曲线可知,算法优化后得到的运动轨迹均能保持连续、平滑,有利于实现对机器人的精准控制。利用机械臂正运动学方程得到了机械臂末端执行器的轨迹曲线,曲线满足铸件搬运的要求,验证了算法的正确性。     

Arm motion analysis using genetic algorithm for rehabilitation and healthcare

The worlds population is quickly aging. With an aging society, an increase in patients with brain damage is predicted. In rehabilitation, the analysis of arm motion is vital as various day to day activities relate to arm movements. The therapeutic approach and evaluation method are generally selected by therapists based on his/her experience, which can be an issue for quantitative evaluation in any specific movement task. In this paper, we develop a measurement system for arm motion analysis using a 3D image sensor. The method of upper body posture estimation based on a steady-state genetic algorithm (SSGA) is proposed. A continuous model of generation for an adaptive search in dynamical environment using an adaptive penalty function and island model is applied. Experimental results indicate promising results as compared with the literature.     

Analysis of the musculoskeletal system of the hand and forearm during a cylinder grasping task

Musculoskeletal disorders of the hand are mostly due to repeated or awkward manual tasks in the work environment and are considered a public health issue. To prevent their development, it is necessary to understand and investigate the biomechanical behavior of the musculoskeletal system during the movement. In this study a biomechanical analysis of the upper extremity during a cylinder grasping task is conducted by using a parameterized musculoskeletal model of the hand and forearm. The proposed model is composed of 21 segments, 28 musculotendon units, and 20 joints providing 24 degrees of freedom. Boundary conditions of the model are defined by the three-dimensional coordinates of 43 external markers fixed to bony landmarks of the hand and forearm and tracked with an optoelectronic motion capture system. External marker positions from five healthy participants were used to test the model. A task consisting of closing and opening fingers around a cylinder 25 mm in diameter was investigated. Based on experimental kinematic data, an inverse dynamics process was performed to calculate output data of the model (joint angles, musculotendon unit shortening and lengthening patterns). Finally, based on an optimization procedure, joint loads and musculotendon forces were computed in a forward dynamics simulation. Results of this study assessed reproducibility and consistency of the biomechanical behavior of the musculoskeletal hand system.     

How the Beast really moves: Cayley analysis of mechanism realization spaces using CayMos

For a common class of 2D mechanisms called 1-dof tree decomposable linkages, the following fundamental problems have remained open: (a) How to canonically represent (and visualize) the connected components in the Euclidean realization space. (b) How to efficiently find two realizations representing the shortest “distance” between two connected components. (c) How to classify and efficiently find all the connected components, and the path(s) of continuous motion between two realizations in the same connected component, with or without restricting the realization type (sometimes called orientation type).For a subclass of 1-dof tree-decomposable linkages that includes many commonly studied 1-dof linkages, we solve these problems by representing a connected component of the Euclidean realization space as a curve in a carefully chosen Cayley (non-edge distance) parameter space; and proving that the representation is bijective. We also show that the above set of Cayley parameters is canonical for all generic linkages with the same underlying graph, and can be found efficiently. We add an implementation of these theoretical and algorithmic results into the new software CayMos, and give (to the best of our knowledge) the first complete analysis, visualization and new observations about the realization spaces of many commonly studied 1-dof linkages such as the amusing and well-known Strandbeest, Cardioid, Limacon and other linkages.     

The habituation of human postural responses to platform perturbations

The purpose of this study was to examine habituation and task on adaptation of postural responses to simulated wave-induced ship motions. Twenty-four participants (12 male and 12 female) performed four different tasks while being exposed to five platform motion profiles during two testing periods. The four tasks performed were: standing feet parallel stance, standing with feet in an in-step stance, holding of a 10 kg load, sagittal lifting/lowering of a 10 kg load. Motion induced correction (MIC) occurrence, corresponding platform motion parameters, and total time spent performing MICs were compared between trials and tasks. It was found that the number of MIC events and total time spent performing MICs differed significantly between trials, with the first trial for participants having more MIC events and more time spent performing postural corrections. The number of MIC events was reduced and total postural correction times were significantly quicker on the second day of testing. Results revealed significant differences in pitch and roll velocities between in-step and parallel standing and significant differences in pitch and roll accelerations between both standing tasks and MMH tasks (p < 0.05). These results suggest that MIC initiation is significantly affected by previous exposure, habituation to comparable platform motions, and task. Differences between tasks suggest that perturbation characteristics of MIC occurrence are potentially affected by shape of the base of support and additional load. These results could help explain difficulties in previous attempts to predict MIC occurrences purely upon platform motion characteristics.Relevance to industryThe results of this research suggest that when working in moving environments adaptation to motions may occur much faster than expected. Further adaptation may also occur after leaving the moving environment. These factors must be considered when evaluating offshore occupations.