The torsion model of soft tissue in virtual surgery

In order to solve the problem of real-time soft tissue torsion simulation in virtual surgeries,a torsion model based on coil spring is proposed to actualize real-time interactions and applications in virtual surgeries. The proposed model is composed of several connected coil springs in series. The sum of torsion deformation on every coil is equivalent to the soft tissue surface deformation. The calculation of the model is simple because the method for calculating the torsion deformation for each coil spring is the same. The virtual surgery simulation system is established on PHANTOM OMNI haptic device based on the Open GL 3 D graphic interface and VC + + software,and it is used to simulate the torsion deformation of virtual legs and arms. Experimental results show that the proposed model can effectively simulate the torsion deformation of soft tissue while being of real-time performance and simplicity,which can well meet requirements of virtual operation simulations.     

利用随机共振提高纹理触觉真实感的实验研究

根据人的触觉感知通道中的随机共振特性,提出了一种改进的增强纹理力触觉表达建模方法.该方法是在原有的基于图像特征提取的纹理接触力模型基础上,加入适量的白噪声信号,以提高虚拟纹理力触觉表达时的真实感.基于6自由度的DELTA手控器,建立了白噪声信号对纹理力触觉表达真实感影响的实验系统.通过纹理感知与匹配试验,定量地研究了白噪声信号的统计参数(即标准差)变化对纹理感知正确率的影响.实验结果进一步验证了人的触觉感知中存在随机共振特性.统计分析结果表明,加入白噪声信号对纹理的辨别率有显著影响,当白噪声信号的标准差取值在0.5±0.1范围内变化时,人对虚拟物体的辨别率最高.     

虚拟物体的力/触觉模型及再现技术研究进展

虚拟物体在受力作用时的形变建模是虚拟环境中力/触觉人机交互的关键.分析了虚拟物体的力/触觉模型及再现技术的研究难点.介绍了当前六种有代表性的力/触觉模型:自由式形变模型、3D ChainMail模型、弹簧-质点模型、有限元模型、Shape-Retaining Chain Linked模型、长单元模型,并在此基础上对这些模型的优缺点进行了比较.最后对力/触觉模型及再现技术的发展趋势进行了展望.     

Abnormal driving behavior identification based on direction and position offsets

Abnormal driving behavior identification( ADBI) has become a research hotspot because of its significance in driver assistance systems. However,current methods still have some limitations in terms of accuracy and reliability under severe traffic scenes. This paper proposes a new ADBI method based on direction and position offsets,where a two-factor identification strategy is proposed to improve the accuracy and reliability of ADBI. Self-adaptive edge detection based on Sobel operator is used to extract edge information of lanes. In order to enhance the efficiency and reliability of lane detection,an improved lane detection algorithm is proposed,where a Hough transform based on local search scope is employed to quickly detect the lane,and a validation scheme based on priori information is proposed to further verify the detected lane. Experimental results under various complex road conditions demonstrate the validity of the proposed ADBI.     

《信号与系统》教学改革探索与实践

信号与系统课程是信息工程类专业的重要技术基础课,针对该课程的特点,提出了转变教学观念、优化课程内容、改革教学手段、建立合理评价体系等一系列课程改革,目的在于使学生掌握必要的信号与系统基本理论,激发学生学习的积极性,提高学生的创新能力和综合素质。将这些措施应用于教学过程中,效果显著。     

虚拟物体力/触觉交互算法的研究进展

虚拟物体在受力作用时的力/触觉交互算法是虚拟环境中力/触觉人机交互的关键。分析了虚拟物体力/触觉交互算法的研究难点。介绍了当前十一种有代表性的力/触觉交互算法,并在此基础上对这些算法的优缺点进行了比较。最后对力/触觉交互算法的发展趋势进行了展望。     

352226X2 滚锥轴承内圈松动的声发射诊断

采用声发射技术对铁路货车轴承352226X2内圈松动故障进行检测,以小波包分析方法提取故障信号的能量特征向量,通过对内圈不松动和松动两种情况下能量分布的比较,提取高频带内能量与总能量之比作为特征参数,可有效地诊断内圈松动故障.     

浅谈《信号与系统》教学改革

针对《信号与系统》课程的教学内容和特点及其在大学生实践创新能力培养中的地位和作用,文章从教学内容的精选、双语教学方法的灵活运用、实验教学的分层次设计等方面给出了一些经验和体会,为培养出具有实践能力与创新精神的高技能型人才而奉献力量。     

支持力/触觉反馈的虚拟肝脏手术仿真系统

为提高支持力/触觉反馈的虚拟肝脏手术仿真系统的精度和实时性,提出了一种基于物理意义的平行菱形链连接变形模型.该模型中由于各个链结构单元中菱形的长度等比例变化,计算量小,改变链结构单元中菱形的长度和夹角就可方便地对不同的柔性体进行建模.同时还讨论了系统的结构设计、柔性体形变计算、快速碰撞检测和实时力/触觉反馈操作等.基于6-DOF Delta手控器建立试验平台,并结合力/触觉反馈计算实现了虚拟肝脏手术的拉拽、按压等变形仿真.实验结果表明,该系统力/触觉感觉平稳、模拟效果逼真,能够满足虚拟现实系统对精细作业和实时性的要求.建立简单逼真的物理变形模型和精确快速的碰撞检测算法,有助于提高虚拟肝脏手术仿真系统的性能.     

轴承内径尺寸机器视觉在线检测技术

利用计算机图像处理技术,对预处理后的边缘图像,采用基于点Hough变换的圆形图像亚像素检测算法,实现了轴承内径的亚像素无损在线检测.该检测系统具有非接触、速度快、精度高、抗干扰性强、成本低、通用性好等优点,可广泛应用于其他行业产品的在线检测.