动物接触力测试系统的研制与应用

研究爬壁动物在爬壁运动时其足掌与接触面间的接触力学规律及其运动步态,可为爬壁机器的设计与控制提供重要启示.研制的动物接触力测试系统由三维力传感器、信号调理模块、数据采集与处理模块、动态图像的记录与分析等组成,可用于树蛙、壁虎等在不同表面状况下的足掌与接触面之间的接触力学测试.利用该系统进行了树蛙垂直表面爬行时的力学测试...     

运动感觉系统加速度在线测试

为了保证飞行模拟器的动态操纵性能,运动感觉系统的参数需要进行测试。基于先进的MEMS技术的双轴加速度计ADXL202,设计了运动感觉系统实时加速度在线测试系统,分析了该系统软硬件设计的特点,讨论了测量的误差和系统抗干扰问题。在实时加速度测试系统中,数据需要从测试仪传送到主机上,为了提高控制的实时性及接受端对数据的反应速度,利用VC++7.0下的Active控件和RS-232串行接口,实现了在WindowsXP环境下,单台PC机与多台传感器的串行通信,并能实时获取各传感器的数据采集。将分立的各传感器组合成一个运动感觉加速度测试系统,经测试后投入实际使用,整个测试系统运行稳定、操作灵活方便。研究结果表明,该加速度传感器具有良好的精度,而且还具有自校准、抗干扰性强、稳定等特点,适合在飞行模拟器检测中应用。     

基于欧拉运动放大算法的桥梁索力测试方法研究

斜拉索、吊杆和系杆是缆索承重桥梁的重要受力构件,但传统的索力测试方法存在操作复杂、 成本高和效率低的缺点,为此开展基于欧拉运动放大算法的索力测试方法研究。采用数码摄像设备采集拉索振 动的数字图像数据,经过基于相位的欧拉运动放大算法处理,获取运动放大后的图像序列;利用基于 Canny 算子的边缘识别算法得到边缘图像序列,并通过边缘定位提取拉索人工标记的位移时程数据;最后利用频率 法识别拉索索力。以拱桥吊杆索力测试为背景,讨论了基于相位的欧拉运动放大算法与基于 Canny 算子的边 缘识别算法的适用情况。与传统基于加速度传感器的索力测试方法相比,该方法具有易操作、低成本和高效 率的特点。     

基于计算机视觉的建筑施工期临时结构损伤识别方法

建筑施工临时结构是施工现场的事故主要风险源。以往的基于振动的临时结构监测方法依赖于在预先分析确定的监测关键部位放置的加速度传感器。但由于临时结构存在构件搭设不规范、施工现场不确定性等因素,通过有限元分析等手段得到的监测关键部位可能与实际情况相差较大,存在不确定性。为此提出一种基于欧拉运动放大算法的临时结构损伤识别方法,充分利用计算机视觉技术的全域覆盖及监测高效的优点。采用数码摄像机采集临时结构的数字图像序列,经过基于相位的欧拉运动放大算法处理,获取运动放大后的数字图像序列;运用Canny边缘识别算法获取边缘图像序列并消除运动放大造成的噪声,通过基于形心的运动跟踪算法获取临时结构的位移时程数据,并利用快速傅里叶变换进行频谱分析;与预先建立的损伤动力指纹库进行对比判断临时结构的损伤状态。以存在10种损伤状态的门式脚手架为测试对象,证明该方法的可行性与适用性。与加速度传感器测量进行对比,该方法平均误差为0.95%,满足临时结构损伤状态识别的精度要求。     

面向肠道平滑肌的微弱肌张力测试系统设计

为了研究胃肠道动力异常造成功能性胃肠病的发病机制。方法 面向肠道器官平滑肌设计了一种高精度、高可靠性、重复性好的肌张力测试系统。测试系统主要包括：肌条夹持装置、肌张力放大装置、霍尔式力传感器、信号处理模块、数据处理与显示模块、微处理器、电源模块。为避免肌条夹持过程中预紧力过大导致断裂，而预紧力过小导致测试失效，采用了基于微处理器的自适应肌条夹持方法；肌张力放大装置采用多级杠杆结构，利用柔性铰链作为杠杆支点实现肌张力的放大，对杠杆结构进行有限元分析和优化，杠杆的放大倍数为145；采用霍尔式差分力传感器与信号处理模块对放大后的力进行测量。结果 基于以上原理，开发了测试系统的样机，并完成了性能验证实验。实验可知：测试系统的灵敏度为34.419V/g，线性度误差为1.627%，重复性误差为0.633%，迟滞性为3.323%。结论 实验结果表明：测试系统能实现0.15g量程以内的肌张力测试，且具有较高的测量精度。     

并联预紧式六维力传感器动态力响应分析

提出一种并联预紧式双层结构六维力传感器,介绍了该传感器的结构特点和优点.并基于多自由度系统振动力学对该六维力传感器进行动态力响应分析.首先结合该传感器的结构特点对其进行静力学分析,在此基础上建立了传感器系统的振动力学模型;然后推导出系统的运动微分方程,通过求解运动微分方程,得到了系统在动态力作用下广义坐标的响应以及各分...     

光电测试系统的性能分析

文章从理论上分析、计算由近红外光电传感器、前置放大电路和采集卡组成的光电测试系统的精度指标.结果表明,系统的绝对误差为6.68 mV;温度和噪声等引起的相对误差为3.26 mV;此外,采集卡的A/D转换宽度也影响着整个系统的精度.文章分析的方法为类似测试系统的性能分析提供了一般方法.     

压电薄膜压力分布计算机测试系统研究

提出了一种新型的压电薄膜（PVDF）压力分布计算机测试系统,它包括多点压电薄膜传感器、多点电荷放大装置、计算机采集处理系统;该系统可以实现全场、实时测量,其动态范围可达0.1～500 Hz;采用微机输出具有独特的图象动画显示,使测量结果更为直观;文中叙述了系统的工作原理以及实验测试,测试结果证实了系统的动态压力分布测量能力;本系统的研制为动态接触问题的研究及振动测试开发了新的研究工具.     

基于上肢力学信息的人体运动意图检测

运动意图检测在人机交互中具有重要作用,是人机交互自然性和可靠性的保障.上肢力学信息与上肢运动意图有某种潜在的关系,探索人体在外界约束条件下上肢力学信息产生和变化规律,通过开发运动意图信息采集系统并实验,可实现基于上肢力学信息的运动意图检测.通过多维力传感器检测得到的人体上肢力信息,并与人的运动意图相结合,找出上肢动作、运动意图、上肢力信息三者之间的关系,探索出一种基于上肢力学信息的人体运动意图检测方法.     

基于压电加速度传感器的振动测量系统研究

为实现对振动的有效测量,构建了压电加速度传感器的振动测量系统;对压电加速度传感器的力学模型及基本原理进行了有效地分析,并采用灵敏度比较法标定传感器,提高了整个测试系统的测量精度和可靠性;并应用了信号处理中的相关滤波原理;测试系统由压电加速度传感器、高速数据采集卡及Labview2010软件开发平台构成;软件功能主要有信号采集、历史数据读取、数据滤波、时频域分析等;搭建了工程实际测振的实验模型,并根据其频谱特性判断内部缺陷;实验结果表明,该测振系统运行稳定,操作简单,具有很好的可扩展性及可移植性,能实现准确、高效、实时的振动测量。     

基于虚拟样机与二型模糊系统的机车粘着控制

为了抑制轮对空转,并使轮轨间的粘着处于极限状态,需要开发基于虚拟样机和现代控制理论的机车粘着控制技术。组建了包括电力机车多刚体动力学模型、电力牵引传动系统和控制系统的仿真平台。针对电力机车牵引系统的强非线性和不确定性,引入二型模糊逻辑以实现机车粘着控制。仿真结果表明,在该仿真平台上能够成功实现基于二型模糊系统的粘着控制,并且能够较好地抑制空转现象,实现优化粘着控制。     

电力机车粘着控制技术的相关问题及其研究现状

电力机车的牵引力和制动力的形成依赖于轮轨间的粘着,粘着性能的优劣决定于粘着控制系统的设计。随着我国高速铁路建设规模的扩大和运载负荷的增加,提高机车粘着控制的性能更加重要。本文主要介绍了粘着系统的基本理论和当前电力机车粘着控制方法的研究现状,详细介绍了三种典型的粘着控制方法并分析了其利弊,最后对粘着控制方法的发展进行了展望。指出粘着控制的发展在于改进和有效组合现有控制方法并发展智能方法。     

Development of Wall Climbing Robot System by Using Impeller Type Adhesion Mechanism

In this paper, we present a wall climbing robot system, called “LARVA”, developed for visual inspection of structures with flat surfaces. The robot has two differential driving wheels with a suspension and an adhesion mechanism. The adhesion mechanism is composed of an impeller and two–layered suction seals. It is designed to provide sufficient adhesion force and be controlled so that the robot can move freely on various wall surfaces. The static and aerodynamic modeling of the adhesion mechanism is given and the analysis of the adhesion mechanism, air leakage, and inner flow are carried out to be useful for the design as well as the control. Finally, the performances of the robot are experimentally verified on several kinds of walls and its feasibility is validated.     

利用小波分析和云模型实现机车优化粘着控制*

分析了电力机车粘着控制系统的基本原理,建立了包含粘着特性的机车牵引力传递模型;利用小波分析消除车轮速度信号中干扰噪声,提高机车空转趋势识别的可靠性。云模型将模糊性和随机性有机地结合在一起,实现定性概念和定量表示间的转换;针对机车牵引系统的强非线性和不确定性,设计了云模型粘着控制器。通过与传统的粘着控制方法对比表明,小波分析和云模型粘着控制方法不但可以有效抑制空转,同时可以实现优化粘着控制。     

Energy-efficacy comparisons and multibody dynamics analyses of legged robots with different closed-loop mechanisms

As for biological mechanisms, which provide a specific functional behavior, the kinematic synthesis is not so simply applicable without deep considerations on requirements, such as the ideal trajectory, fine force control along the trajectory, and possible minimization of the energy consumption. An important approach is the comparison of acknowledged mechanisms to mimic the function of interest in a simplified manner. It helps to consider why the motion trajectory is generated as an optimum, arising from a hidden biological principle on adaptive capability for environmental changes. This study investigated with systematic methods of forward and inverse kinematics known as multibody dynamics (MBD) before going to the kinematic synthesis to explore what the ideal end-effector coordinates are. In terms of walking mechanisms, there are well-known mechanisms, yet the efficacy is still unclear. The Chebyshev linkage with four links is the famous closed-loop system to mimic a simple locomotion, from the 19th century, and recently the Theo Jansen mechanism bearing 11 linkages was highlighted since it exhibited a smooth and less-energy locomotive behavior during walking demonstrations in the sand field driven by wind power. Coincidentally, Klann (1994) emphasized his closed-loop linkage with seven links to mimic a spider locomotion. We applied MBD to three walking linkages in order to compare factors arising from individual mechanisms. The MBD-based numerical computation demonstrated that the Chebyshev, Klann, and Theo Jansen mechanisms have a common property in acceleration control during separate swing and stance phases to exhibit the walking behavior, while they have different tendencies in the total energy consumption and energy-efficacy measured by the ‘specific resistance’. As a consequence, this study for the first time revealed that specific resistances of three linkages exhibit a proportional relationship to the walking speed, which is consistent with human walking and running, yet interestingly it is not consistent with older walking machines, like ARL monopod I, II. The results imply a similarity between biological evolution and robot design, in that the Chebyshev mechanism provides the simplest walking motion with fewer linkages and the Theo Jansen mechanism realizes a fine profile of force changes along the trajectory to reduce the energy consumption acceptable for a large body size by increasing the number of links.     

Flat Dry Elastomer Adhesives as Attachment Materials for Climbing Robots

In this paper, flat elastomers are proposed as an attachment material for climbing robots on less than a few micrometer-scale rough surfaces due to their energy-efficient, quiet, and residue-free characteristics. The proper elastomer is chosen by the use of the current adhesion, friction, and peeling elastomer-contact-mechanics models. Then, adhesion and friction properties of the chosen dry flat-elastomer thick films (Vytaflex-10) are characterized on acrylic and smooth and rough glass surfaces for variations in preloads, speeds, contact times, and elastomer thicknesses. A climbing robot with four-bar-based legged-body kinematics is designed and fabricated as simple and lightweight as possible to demonstrate the feasibility of the elastomers as attachment materials on relatively smooth surfaces. The robot utilizes a passive alignment system to make the footpads parallel to the surface on light contact, a peeling mechanism to minimize the detachment vibration, and a passive tail to minimize the pitch-back moment. Experimental results showed that the robot can climb stably on vertical, smooth surfaces in any direction and can walk inverted for a limited amount of time.      

Development of a Tracked Climbing Robot

This paper describes a climbing robot, using chain-track as the locomotive mechanism and suction cups as the adhesion method. The main structure, sensors, and the vision-based motion control system of the robot are described in the paper. The robot can turn in a limited range by adjusting the steering wheel and twisting the chain. The turning gait is discussed and relations between turning angles of the chain node, the front wheel, and the frame of the robot are formulated. Forces applied to the robot are analyzed in order to obtain a safety condition that prevents the robot from slipping and falling. An experiment is conducted to measure the safety factor of suction cups and determine the payload capacity of the robot.     

Analysis of the unique gait mechanism of locusts focusing on the difference in leg length

The various types of gaits shown by insects are very interesting, and many studies have been conducted to investigate the mechanism of these gaits. In nature, there are many insects with apparent differences in the length of each leg, and it seems that the difference in leg length may affect the resultant gait of insects. However, there has not been much discussion about the influence of these differences in leg length on the gait. In this research, in order to investigate the influence of the difference in leg length on gait, we focus on locusts, whose hind legs are considerably longer than the other legs and shows a unique gait not seen in other insects. First, we measure the kinematics of gait of some insects, including locusts, and analyze the unique gait specific to locusts. Next, we reproduce this unique gait via numerical dynamical simulation. By conducting some simulations while changing the length of the legs, we investigate the mechanism of the unique gait of locusts and the influence of difference in leg length on walking. As a result, it is confirmed that the unique gait of locusts can be reproduced with a combination of long hind legs (compared to the front and middle legs) and the adjustment of the stroke and period of the hind leg based on horizontal ground reaction force.     

Experimental Study of In-Plane and Out-of-Plane Adhesions in Microelectromechanical Systems

Two different but similar microdevices were used for studying in-plane (IP) and out-of-plane (OP) adhesions in microelectromechanical systems (MEMS). With these devices, the combined influence of temperature, surface chemistry, contact geometry, and applied load on the adhesion force was investigated. The adhesion force is the maximum force required to separate two contacting surfaces. Distinguished between IP and OP contacts, the adhesion mechanisms for hydrophilic and hydrophobic surfaces were identified. The microdevices, fabricated within the same wafer, may exhibit different IP and OP adhesion mechanisms, dependent upon the wafer surface chemistry. For the hydrophilic surface and IP contact, the dominant adhesion mechanism is hydrogen bonding, while for OP contact, the electrostatic force is dominant. The dominant adhesion mechanism for the hydrophobic surface is the Van-der-Waals force for both IP and OP contacts. Furthermore, the influence of elastic–plastic deformation of interacting asperities on the adhesion force is addressed by experiments at different loads. At constant applied load in a cycling contact–release test, a decreasing and asymptotic behavior of the adhesion force is observed, suggesting strain hardening and reverse plastic deformation of the contacting asperities.$ hfill$[2009-0117]