应用于人工皮肤的压电驻极体触觉传感阵列研究

基于聚丙烯压电驻极体(Piezoelectret)设计了一种应用于人工皮肤的触觉传感器。该传感器具有柔性良好、压电效应稳定、制备简单、成本低廉等特点。通过触压、滑动、同时触压与滑动、恒定力重复触压等实验,可观察到该传感器对不同触觉信号具有明显的特征差异,且阵列传感器的信号检测稳定性比单路传感器高40%。将该传感器置于假肢手指前端反馈触觉信号,并根据触觉信号调控假肢手的抓握力,可实现对易脆和光滑物体的稳定抓握。     

应用于人工皮肤的压电驻极体触觉传感阵列研究北大核心CSCD

基于聚丙烯压电驻极体(Piezoelectret)设计了一种应用于人工皮肤的触觉传感器。该传感器具有柔性良好、压电效应稳定、制备简单、成本低廉等特点。通过触压、滑动、同时触压与滑动、恒定力重复触压等实验,可观察到该传感器对不同触觉信号具有明显的特征差异,且阵列传感器的信号检测稳定性比单路传感器高40%。将该传感器置于假肢手指前端反馈触觉信号,并根据触觉信号调控假肢手的抓握力,可实现对易脆和光滑物体的稳定抓握。     

糖尿病合并慢性骨髓炎保肢治疗

触觉和滑觉检测是机器人实现物体抓取的关键环节,尤其是滑觉检测对实现软抓取尤为重要.该文设计了一种同时具有触觉和滑觉检测的新型触滑觉传感器.触觉检测基于聚偏氟乙烯(PVDF)膜的三向力传感技术,通过分析得到了计算空间三向力的公式;滑觉检测基于光电原理,将滑动引起的微小振动信号转化为光电信号.通过大量仿真试验得出了触觉、滑觉响应曲线,并确定了判定滑动信号的阈值.     

一种简单的单频无源LC传感器读取系统设计

为了实现无源LC传感器信号的高灵敏度检测,提出了一种简单、高效的单频无源LC传感器读取系统,该系统通过磁耦合读取线圈和传感器线圈,利用固定电容与电容传感器并联降低谐振频率以便进行测量,首先,通过读取线圈将传感器的电容转换成励磁电压和电流之间的相角(?),然后使用相敏检测器获得由tan?给出的最终输出结果，其中，相敏检测器的输入为电压和与信号成比例的电流。理论分析和实验结果显示，提出系统能够实现传感器变化信号的高灵敏度检测，在 ±５ｐＦ的范围内测试得到的灵敏度为5.5 (°)/ｐＦ且平均误差约为0.38％。     

基于压电式新型三维力传感器的设计

从生物压电效应和人体“皮肤效应”原理出发，提出了一种基于压电式的新型三向力检测方法，阐述了三向力传感器的设计思想和基本组成结构，并从理论上对传感器工作原理进行了检测，推导了计算空间三向力大小和方向的公式。该三向力传感器不但可以用于机械空间力的测量，且还可用于机器人表皮的传感，为实现新型的智能机器人触觉力传感器系统提供了一种新的方法。     

微电容式传感器信号检测电路的设计

微电容传感器检测电路是微电容传感器中的关键技术,由于微电容传感器的电容变化量很小,电路中的杂散电容对传感器的影响就会非常大,所以微电容测量电路必须具备大动态范围、高测量灵敏度、低噪声、抗杂散性好等性能。因此提出了电桥式交流电容检测电路。首先将转换后的电压信号加载到高频正弦激励信号中,然后通过放大等一系列处理得到输出电压,最后根据待测电容与输出电压的关系得到待测电容的容抗。(１)采用Multisim仿真软件对提出的电桥式交流电容检测电路进行了调试及可行性验证。(２)在设计的基础上对电路进行了实物焊接和调试。(３)利用信号发生器和示波器对一批已调试的微电容进行了实验验证。实验结果表明,提出的电桥式交流电容检测电路测量的输出电压与理想情况下的输出电压基本一致?且该电路能很好地抑制寄生电容的影响,有良好的线性和稳定性。     

电容式湿度传感器的设计

为了能够更好解决测量流动蒸汽湿度准确度低、难度大等问题,设计了一种电容式湿度传感器,其为同轴圆筒式多极电容传感器结构,利用电容数字转换技术芯片PCap01进行电容值的检测,通过SPI通信方式将测量结果传输到STM32单片机中进行处理,采用AD421将输出结果转换为标准的4~20 m A信号。实验结果表明,在一定温度下,随着产生湿度的变化,湿度与输出电流呈线性关系,当产生的湿度不变时,电流趋于稳定状态,该设计能够进行湿度的测量。     

应用平行极板式电容传感器检测润滑油品质的研究

分析和探讨了润滑油介电常数变化的微观原因,并基于介电常数测量原理,以实现润滑油质量的现场快速检测为目的,考虑灵敏度、信噪比、击穿电压等参数要求,设计了平行极板式电容传感器。采用谐振法对不同使用期的油样进行了测试实验,其中重复性测试数据的最大偏差为4,8％。应用计及边缘效应影响的计算公式对数据进行了处理,结果表明该传感器能在不改变机器内部油路结构的情况下快速有效地检测油液介电常数的变化,为科学判断润滑油使用状况提供依据。     

一种MEMS扭摆式强磁场测量传感器

提出了一种扭摆式结构的MEMS电容式强磁场传感器,采用洛伦兹力驱动,通过测量硅板扭摆导致的电容变化来检测外部磁场强度,测量磁场的量程设计在0.2T-2T之间。首先介绍了传感器的工作原理,然后对其进行仿真,分析其物理特性,建立了模型并且求解出各阶模态下的振动形式,得到传感器主振模态频率为28.26kHz。并模拟了受力过程中的形变量。最后介绍了其制造工艺流程,验证了传感器加工的可行性。     

基于作物茎杆生理电容式水分传感器的研究

准确检测作物生长的水分状况,对灌溉决策十分重要。本文介绍了作物茎杆生理电容式水分传感器的原理及电路设计,该传感器可实现对作物生长水分状况的无损检测,通过试验证明该电容传感器测量作物含水量的变化是可行的。基于茎杆生理电容变化的作物水分非破坏性检测技术,研制结构简单、测量准确、抗干扰能力强的作物水分测量传感器,对丰富节水灌溉技术和传感器技术具有重要的意义。     

非本征F-P干涉仪式光纤触觉传感器的研究

基于法布里-珀罗(F-P)干涉原理,设计制作了具有核磁共振成像(MRI)兼容能力的光纤非本征F-P干涉仪(EFPI)结构的触觉传感器。在整个光纤触觉传感系统中,利用螺旋微控装置对传感器施加力,通过光谱分析(OSA)测量干涉光谱,利用交叉相关解调技术解调出传感器腔长,同时由FS20系列力传感器进行标定。对传感器的性能指标进行了分析,本文传感器的测量范围为0～3N,测量分辨率为0.02nm,多次测量结果显示和理论的吻合度较高。     

新型磁驱动增大检测电容的高精度MEMS惯性传感器研究

增大传感器振子的质量和静态测试电容可以减小电容式MEMS惯性传感系统的噪声,而深度粒子反应刻蚀工艺由于复杂的工艺原因,当深宽比较大时,不能刻蚀出大质量和大初始电容的传感器.据此,本文研究了一种磁驱动增大检测电容的MEMS惯性传感器,通过电磁驱动器,传感器的静态测试电容可以大幅增加,在梳齿电容上刻蚀阻尼槽后,其机械噪声达到0.61μg每根号赫兹,仿真其共振频率为598Hz,静态位移灵敏度为0.7μm每重力加速度,基于硅 玻璃键合工艺,制作了栅形条电容式惯性传感器,并用电磁驱动的方式测试其品质因子达到715,从而验证了制作工艺的可行性和电磁驱动器改变传感器初始静态测试电容的可行性.     

Design and implementation of capacitive proximity sensor usingmicroelectromechanical systems technology

This paper presents an innovative proximity sensor using microelectromechanical systems (MEMS) technology. The proximity sensor works on the principle of fringe capacitance. The target object does not need to be part of the measuring system and could be either a conductor or nonconductor. Modeling of the proximity sensor is performed and closed-form analytical solution is obtained for a ring-shaped sensing pattern. The proximity sensors could be batch fabricated using MEMS technology, and the fabrication process is relatively simple. Measurement of the prototype sensors revealed promising results. The size of the proximity sensor could vary from a few hundred micrometers to the size of the substrate. The flexibility on sensor size, sensing patterns, and sensing pattern geometrical parameters makes the sensor very versatile and capable of precision measurement of proximity in the range from micrometers to centimeters. The small size of the sensor makes it possible to surface mount the sensor in many space-constrained places. This advantage is vital in many areas, such as MEMS, microrobotics, precision engineering, machine automation, inspection tools, and many other applications. The ability of the proximity sensor in measuring relative permittivity of materials also finds the sensor useful applications in biomedical and tissue engineering. In addition, this micro proximity sensor is an ideal building block for many other types of sensors, such as force, tactile, and flow sensors     

基于双叉指电容和ZIGBEE的无线位移传感器

微位移测量技术可以实现微距环境下的位置感知与位移操作,其关键在于对位移的精密测量及实时传输。本研究基于平面双叉指电容和ZIGBEE技术设计了一种无线位移传感器系统,该系统由四部分组成：位移一电容转换模块,电容采集、发送节点,电容接收节点,基于VC＋＋开发的实时监控及结果显示软件。此外,下位机是基于ZIGBEE无线通信协议开发的。通过实验证明：系统具备6mm的测量范围,10um的分辨率,通信距离50m。     

Intrinsic tactile sensing for the optimization of force distribution in a pipe crawling robot

Describes a tactile sensing system based on a force/torque sensor for the feet of a pipe crawling robot. Such a sensing system is needed for better optimization of force and joint load distribution and a safer avoidance of the risk of foot slippage. While conventional tactile sensing devices typically provide information concerning the spatial distribution of normal pressures, the intrinsic contact sensing system presented in this text only measures the three components of the contact force and two components of the resultant torque. These five parameters are shown to be sufficient to estimate the location of the contact point and hence the orientation of the local contact surface. Such information can then be used by the crawler's control system for the real-time computation of an optimized foot force distribution. The intrinsic tactile sensing method has been experimentally tested on a single leg test setup, while the optimization of force distribution is already functioning in the TUM Pipe Crawling Robot (only with a different, more unripe, sensing system for the contact orientations)     

Piezo displacement sensors for a compact high-speed x–y nanopositioner in differential actuation mode

An emerging actuation technique in piezo driven nanopositioners is differential actuation, where each axis has two opposing actuators that operate differentially and provide bilateral motion. It has simultaneous benefits of improving linearity and range of displacement. However, few methods for displacement sensing employing in-situ transducers have been considered for this kind of nanopositioners. We address a novel application of PZT piezoelectric chips for direct displacement sensing in differentially driven nanopositioners. First, an electromechanical force analysis is performed in order to increase the PZT sensor sensitivity through the structural design of the nanopositioner. Secondly, the sensing performances of the proposed in-situ PZT sensor are compared with those from an alternative built-in piezoresistive (PZR) strain gauge sensor under equal circumstances, in different sensing and actuation configurations. While the PZR sensor has a larger sensing bandwidth than the PZT one and performs better if the actuation frequency is smaller than 30 Hz, the PZT sensors provides better accuracy when the actuation is well within its sensing bandwidth. The accuracy of the differential sensors and the input-displacement linearity are improved when the mechanical preload force magnitudes on the opposing actuators are balanced. The differential PZT sensor can provide accurate measurements even in a non-differential mode after recalibration.     

Ultrasoft Liquid Metal Elastomer Foams with Positive and Negative Piezopermittivity for Tactile Sensing

Soft, capacitive tactile (pressure) sensors are important for applications including human–machine interfaces, soft robots, and electronic skins. Such capacitors consist of two electrodes separated by a soft dielectric. Pressing the capacitor brings the electrodes closer together and thereby increases capacitance. Thus, sensitivity to a given force is maximized by using dielectric materials that are soft and have a high dielectric constant, yet such properties are often in conflict with each other. Here, a liquid metal elastomer foam (LMEF) is introduced that is extremely soft (elastic modulus 7.8 kPa), highly compressible (70% strain), and has a high permittivity. Compressing the LMEF displaces the air in the foam structure, increasing the permittivity over a large range (5.6–11.7). This is called “positive piezopermittivity.” Interestingly, it is discovered that the permittivity of such materials decreases (“negative piezopermittivity”) when compressed to large strain due to the geometric deformation of the liquid metal droplets. This mechanism is theoretically confirmed via electromagnetic theory, and finite element simulation. Using these materials, a soft tactile sensor with high sensitivity, high initial capacitance, and large capacitance change is demonstrated. In addition, a tactile sensor powered wirelessly (from 3 m away) with high power conversion efficiency (84%) is demonstrated.     

三自由度介电型EAP软材料位置传感器研究

基于介电型电活性聚合物(EAP)变形时的电容值变化原理,设计并实现一种三自由度软材料位置传感器,其内框可沿平面和法向移动,分别用于检测平面和法向位移。建立该传感器的几何模型,推导出其电容值变化和内框位移的关系。采用差分法测试该传感器的电容值变化,分析了面对面两个传感单元的电容值差和内框的平面位移、单个传感单元的电容值和内框的法向位移之间的关系,测试得到其平面和法向位移灵敏度分别为66.69pF/mm、0.47pF/mm~2,与理论分析结果较吻合。该位置传感器的理论与测试分析结果验证了介电型EAP应用于位置传感器中的可行性。     

Instrumented rubber insole for plantar pressure sensing

We demonstrate a printed pressure sensor embedded rubber insole for measurement and analysis of plantar pressure. Unlike the conventional mode of pressure sensing of interdigitated capacitors in which change in dimension of electrodes by external pressure leads to variation of capacitance, for this study, the change in capacitance is entirely led by variation of relative permittivity of the surrounding dielectric medium with applied pressure. The measured sensitivity of the sensor is 4.3 V/MPa and shows high linearity in the pressure exerted by human weight. The plantar pressure is detected with locally embedded sensors to register various foot postures at three high-pressure regions: hind-foot, mid-foot, and fore-foot.     

Novel capacitance-type humidity sensor based on multi-wall carbon nanotube/SiO2 composite films

A novel capacitance-type relative humidity (RH) sensor based on multi-wall carbon nanotubc/SiO2 (MWCNTs/SiO2) composite film is reported.Details of the fabrication process,possible sensing mechanism and sensing characteristics,such as linearity and sensitivity,are described.The capacitance of the MWCNTs/SiO2 composite film shows typical concentration percolation behavior with increasing MWCNT loading.At loadings below the percolation threshold (1.842wt％),the sensor capacitance increases obviously with increasing MWCNTs.The water condensed in the MWCNTs/SiO2 layer can lower the percolation threshold and increase the sensor capacitance.The sensor with MWCNT concentration of 1 wt％ has the best properties.The sensor has a humidity sensitivity of about 673 pF/％ RH and a linearity correlation of 0.98428.The response time of the sensor to RH is about 40 s and the recovery time is about 2 s.