基于定位与姿态感知的虚实漫游方法应用研究

随着虚拟现实技术的成熟,文化遗产数字化保护与传承越来越受到人们的关注。 通过GPS 定位与移动终端的结合,实现智能移动终端GPS 在展示古迹废墟遗址方面的优势。 具体方法是,首先通过数据转换,建立虚拟场景与真实场景的区域映射;然后使用陀螺仪将摄 像机的角度与智能移动终端绑定,建立虚拟角色与现实角色的姿态映射,最后通过Unity3D 插 件包实现虚实漫游功能,打破时间与空间限制,丰富展示作品的信息量与趣味性,并提供一种 个性化的文化遗产场景浏览模式,可应用于遗址废墟如圆明园场景。     

基于智能手机的实时跌倒检测系统研究

为减少跌倒对老年人造成的伤害,并对跌倒进行实时检测,提出了一种基于Android智能手机的人体跌倒检测系统,手机安置于腰上采集手机加速度传感器数据,利用了姿态识别和跌倒检测相结合的算法,区分出跌倒行为和人体日正常常活动。当检测到异常跌倒时,报警信息以及从手机中GPS获取的位置被发送。仿真及实验表明：系统能够有效地识别出跌倒和日常行为,算法具有较高实时性、具有较高灵敏度和特异度。     

三维人体点云模型多约束肢体分割

针对人体点云模型的肢体分割这一动作识别和虚拟重建领域的重要问题,提出了一种基于分类骨架线、测地距离、特征点和姿态分析的多约束肢体分割算法,通过生成点云模型的分类骨架线,配合测地距离获得人体各部位粗分割点云集,利用测地路径方法实现关键特征点的定位,并利用曲线拟合方式进行定位优化,针对头颈、上肢、下肢和躯干之间关联部位的解剖学特征,构造多种约束条件,对各部位粗分割点云集进行了优化再分割。实验结果表明,所提算法对站姿条件下的不同动作、不同体型、不同精度人体点云模型均能取得与视觉理解相吻合的分割效果。通过该算法得到的肢体各部分点云数据可用于姿态分析等后续研究。     

导向钻井工具冗余姿态测量与系统重构方法

为实现调制式导向钻井工具井眼轨迹的精确可靠控制,导向钻井工具井下姿态的实时测量至关重要。针对恶劣工况下测量系统可靠性差的问题,提出了一种非正交四轴重力加速度计的姿态测量方法,给出了对应的姿态参数求解和信号有效性判定公式。针对小井斜状态下姿态参数测不准问题,提出了四轴重力加速度计初始倾斜安装的非正交测量方法,显著提高了测量精度。针对井下恶劣工况中加速度计易损易失效问题,提出了双冗余非正交四轴重力加速度计测量方法,给出了双冗余重力加速度计关联信号的相互转换公式,讨论了依据信号特征判定重力加速度计故障的方法及故障诊断流程,并据此建立了系统重构方案。水力驱动测试实验表明,工具姿态测量准确,控制平台角度位置稳定。     

经直肠超声探头位姿调整远心机构设计及实验研究

在临床手术中,最常用于诊断前列腺癌的方法是经直肠超声的前列腺活检手术。医生在手术期间需要全程手持超声探头进行反复调整,难以保证手术的效率、精度以及安全性。通过对经直肠超声引导下前列腺活检手术流程的分析,设计了一种7自由度被动式经直肠超声探头位姿调整远心机构。基于双平行四边形机构设计的姿态调整模块实现超声探头的定心功能,并对其进行运动学分析,基于SimMechanics对超声探头不同进给距离时的工作姿态和定心效果进行了仿真。研制了被动式经直肠超声探头位姿调整机构的物理样机,并进行了测量实验,实验结果可知超声探头不同进给距离时方位角远心点运动最大误差和俯仰角远心点运动最大误差分别为4和3.4 mm,均小于肛门处可承受的变形量6 mm。在不同方向下的随机误差相关性较弱,方位角和俯仰角的远心点运动误差置信区间均小于2.5 mm,最大相对定点误差和最大相对标准误差分别为14.73%和14.98%。仿真和实验结果以及测量误差的分析均验证了超声探头位姿调整机构定心性能的有效性和稳定性。     

基于C8051F040水下平台姿态监测电路设计

为了监测某水下释放平台的航向角、横滚角、俯仰角以及深度值,采用C8051F040为控制器的数据监测电路。平台姿态数据由陀螺计算得到,深度值由传感器输出的模拟信号经 C8051F040内部A/D模块获得,同时将这些数据通过RS422串口发送出去。应用结果表明,该监测电路达到设计要求,并具有一定的实用性及应用价值。     

几种静态姿势的负荷评价与工作设计

以２５名大学生志愿者为对象，通过实验室模拟生产中常见的几种静态姿势，测定和分析了他们的肺通气量、心率及Ｂｏｒｇ量表分值的变化。结果发现自然坐位和站位情况下，随手臂不同程度地前伸和上举，肺通气量、心率、Ｂｏｒｇ量表分值连续地升高，至双臂９０°上举达到最高值。结果说明，肺通气量、心率及Ｂｏｒｇ量表分值均可在一定程度上反映静态劳动的负荷。手上举及手完全前伸的作业姿势无论从劳动生理还是生物力学的角度看都是不合理的，在工作上应尽量加以避免。     

Effects of sitting and standing, reach distance, and arm orientation on isokinetic pull strengths in the horizontal plane

In recent years, isokinetic strengths (dynamic strength exertions at constant speed) have almost replaced isometric (static) strengths in laboratory studies as measures of a person's strength exertion capabilities. Many industries are also showing a keen interest in replacing static strength usage with dynamic strength usage. The increasing acceptance of isokinetic strengths as a more valid and accurate measure of people's strength exertion capability has necessitated the development of isokinetic strength databases. This paper presents one-arm isokinetic pull strength profiles of males, engaged in infrequent exertion in a horizontal plane, as a function of posture (sitting and standing), reach distance (25, 40, and 55 cm for the sitting posture; 45, 65, and 85 cm for the standing posture), and angle of the preferred (stronger) arm from the frontal plane (0—frontal plane, 30, 60, 90, 120, and 150 deg). Twenty-five males participated in the study. The results indicated that more strength is exerted while standing. The strength also increases with the reach distance. The strength exertion becomes stronger as the angle of the arm increases to 90° from the frontal plane (i.e., the arm moves to the sagittal plane) and then weakens.     

Evaluation of reaction time performance and subjective workload during whole-body vibration exposure while seated in upright and twisted postures with and without armrests

There is little knowledge on performance during vibration exposure combined with occupational hazards such as bent or twisted postures. In addition, little information is available on the effective use of armrests during performance-related tasks. This paper investigates the influence of sitting in different working postures on the reaction time and perceived workload of subjects exposed to whole-body vibration. Twenty-one subjects were exposed to 1–20 Hz random vibration in the vertical and fore-and-aft directions. A choice reaction time task was completed while seated in four posture conditions: upright or twisted, with and without armrests. Following the task, participants completed the NASA TLX workload assessment. Posture combined with whole-body vibration exposure had a significant influence on the ability to perform the task. The combined environmental stressors significantly degraded the performance; not only did their reaction times become compromised, the participants’ workload demand also increased. The most severe decrement in performance and workload was experienced while seated in a twisted posture with no armrest support. The inclusion of armrests significantly improved the participants’ ability to complete the task with a lower workload demand.

Relevance to industry

Twisted postures have been observed in a variety of machine operations and it is important to determine their influence on operator workload. Many off-road machines have suspension seats fitted with armrests; this paper demonstrates that armrest support provides additional benefits for off-road machine operators under combined environmental stressors.     

基于机器视觉掘进机位姿检测应用现状与趋势

机器视觉技术依靠非接触、获取信息丰富的特点,在煤矿智能化的进程中得到了广泛应用,同时在煤炭开采中,掘进机的位姿检测有利于掘进机的自动化以及智能化操作进而有利于煤矿智能化进程的推进,不仅能缓解采掘失衡的矛盾,同时能降低工人的劳动强度,本文分析了近几年来机器视觉技术在掘进机位姿检测中的应用现状与趋势,研究了各种掘进机位姿检测方法中所涉及的图像预处理以及位姿检测模型的关键共性问题,并就关键共性问题,提出了机器视觉技术在掘进机位姿检测的应用中,应在图像采集硬件、位姿检测的冗余性以及特征提取的精确性方面做出突破。