三维柔性触觉/热觉传感器设计与仿真

针对目前触觉传感器研究中不能兼有柔韧性、多维力测量和热觉与触觉信号混杂等难题,设计了一种柔性多功能触觉/热觉传感器。介绍了该传感器的基本结构,并基于聚偏氟乙烯（ PVDF）薄膜的特性建立了三维力并行测量的数学模型。触觉检测基于PVDF的压电效应,热觉检测基于PVDF的热释电效应。通过对触觉和热觉信号做比例减法运算,从而彻底区分触觉和热觉信号。     

具有触觉和肌电控制功能的仿生假手研究

研究一种能感知接触和滑动、且由肌电信号控制的高仿生能力电动假手.触滑觉组合传感器以压电材料PVDF为敏感体,安装于仿生电动假手的手指上,具有良好的动态触、滑传感能力,同时,假手佩戴者通过一皮肤刺激器获得人工触滑感觉.用改进后的功率谱比值与基于Bayes统计决策的多信息融合相结合的方法完成肌电信号的多运动模式识别,并在电动假手的控制上,采用肌电信号与触滑感觉信号作为双重控制信号源,取得了良好的仿生控制效果.     

基于PVDF的三维机器人触觉传感器有限元分析

为了解决压电层合板层间应力连续性问题,从而更为准确地预测传感器的实际输出,利用COMSOL Multiphysics对基于PVDF压电薄膜的三维机器人触觉传感器进行有限元建模。利用三维线性理论建立了压电层半解析轴对称有限元模型,得出分别沿三个方向施加单向力时触觉传感器各压电薄膜的电压响应。仿真结果与标定值之间的误差小于6%,验证了设计的合理性和可行性。     

敏感高分子“人工皮肤” 力觉感受器 的数学理论依据

本文以PVDF敏感材料的结构性能为出发点,对机器人触觉传感器——人工皮肤的理论基础进行了研究,并就PVDF的压电性从弹性力学的角度进行了分析。在此基础上给出了这一变形体的非线性动态系统的数学描述,为精确而有效地采集力觉感受器的压电信号奠定了基础,为机器人触觉力传感器的设计与制造提供了理论依据。     

基于新型多模态触觉传感器的机器人交互物体分类

多模态传感融合对于机器人探索外界环境十分重要,而现有的触觉传感器只能收集一种触觉模态信息,其收集到的多模态信息存在弱配对问题,为了解决此问题,研究了一种基于触觉和视觉融合的多模态触觉传感器。该传感器可以利用一个感知层同时收集2种异构触觉模态信息,弥补了传统触觉传感器的缺陷,同时可以利用收集到的多模态信息对不同物体的几何形状进行分类,在研究过程中,通过按压实验收集了圆形、正方形、长方形和三角形4种形状物体的触觉信息,再利用K最近邻(KNN)算法进行几何形状分类,实验结果证明了该传感器在区分不同物体的形状上具有良好的效果。     

Multiplexed piezoelectric polymer tactile sensor

An electrically multiplexed robotic tactile sensor has been realized using a monolithic silicon-integrated circuit coupled to a piezoelectric polyvinylidene fluoride (PVDF) film. The integrated circuit incorporates 25 sensor electrodes arranged in a symmetrical 5 × 5 matrix. Each electrode occupies a 600 × 600 m?m square area, and they are separated from each other by 600 m?m. A 25-m?m thick PVDF film was experimentally determined to be compatible with the fabrication process, and also yielded very favorable tactile sensing performance characteristics. The response of the tactile sensor is essentially linear for loads spanning 0.8 to 60 g force (gmf). The response bandwidth is 33 Hz, the hysteresis level is very small, and crosstalk is not a significant problem. A novel precharge bias scheme has been implemented to stabilize the pre- and postload sensor response. A rudimentary tactile object image measurement process was evaluated to recognize the shapes of circular, rectangular, toroidal, and hexagonal loads.     

Electrostatic tactile display with thin film slider and its application to tactile telepresentation systems

A new electrostatic tactile display is proposed to realize compact tactile display devices that can be incorporated with virtual reality systems. The tactile display of this study consists of a thin conductive film slider with stator electrodes that excite electrostatic forces. Users of the device experience tactile texture sensations by moving the slider with their fingers. The display operates by applying two-phase cyclic voltage patterns to the electrodes. The display is incorporated into a tactile telepresentation system to realize explorations of remote surface textures with real-time tactile feedback. In the system, a PVDF tactile sensor and a DSP controller automatically generate voltage patterns to present surface texture sensations through the tactile display. A sensor, in synchronization with finger motion on the tactile display, scans a texture sample and outputs information about the sample surface. The information is processed by a DSP and fed back to the tactile display in real time. The tactile telepresentation system was evaluated in texture discrimination tests and demonstrated a 79 percent correct answer ratio. A transparent electrostatic tactile display is also reported in which the tactile display is combined with an LCD to realize a visual-tactile integrated display system.     

具有触觉临场感和肌电仿生控制功能的遥控机械手研究

提出了一种结合触觉临场感和肌电仿生控制技术的遥控机械手控制方法．采集手臂皮肤表面的肌电信号（表面EMG）,结合AR模型和贝叶斯分类方法判断出手部的运动模式,控制机械手完成相应的动作．触滑觉组合传感器以压电材料PVDF为敏感体,安装于遥控机械手的手指上．机械手抓握或触摸物体时产生触滑觉,触滑觉信号经处理后通过电刺激来刺激操控人员,实现触觉临场感;操控者可根据触觉临场感来掌握自己的手部动作．实验表明,所提方法能提高遥控机械手的仿生控制能力．     

PVDF压电薄膜制作传感器的理论研究

用PVDF压电薄膜设计传感器是近年来在传感器领域研究的一个新热点,通过对PVDF压电薄膜的压电性能的分析,根据弹性力学的薄板理论和压电效应的物态方程,导出PVDF压电薄膜的传感方程,并对偏转角口的情况进行了讨论;为用PVDF压电薄膜制作传感器提供理论基础。     

Integrated distributed sensing and active vibration suppression of flexible manipulators using distributed piezoelectrics

Structural oscillation of flexible robot manipulators would severely hamper their operation accuracy and precision. This article presents an integrated distributed sensor and active distributed vibration actuator design for elastic or flexible robot structures. The proposed distributed sensor and actuator is a layer, or multilayer of piezoelectric material directly attached on the flexible component needed to be monitored and controlled. The integrated piezoelectric sensor/actuator can monitor the oscillation as well as actively and directly constrain the undesirable oscillation of the flexible robot manipulators by direct/converse piezoelectric effects, respectively. A general theory on the distributed sensing and active vibration control using the piezoelectric elements is first proposed. An equivalent finite element formulation is also developed. A physical model with distributed sensor/actuator is tested in laboratory; and a finite element model with the piezoelectric actuator is simulated. The distributed sensing and control effectiveness are studied.     

A digital piezoelectric accelerometer with sigma-delta servo technique

This paper presents the design and performance of a direct digital accelerometer using oversampling sigma-delta servo electronics. The measuring system, also called an ‘electromechanical sigma-delta modulator’, is based on a piezoelectric measuring cell integrated inside the first stage of a second-order sigma-delta modulator. The piezoelectric measuring cell has a new structure in order to realize the acceleration sensing and the servo-loop summer. The active material used in an inexpensive and versatile piezoelectric polymer, polyvinylidene fluoride (PVDF). The accelerometer aims at a working range of ± 1 g and eight-bit resolution. It is suited for vibration measurement.     

PVDF传感器和WSN的振动信号测量系统

为了满足振动传感器阵列对多点信号实时传输的要求,研制了一种基于压电薄膜(PVDF)传感器以及无线传输的振动信号测量系统。该系统包含振动信号采集模块及主控单元,前者集成了振动信号调理电路、ATmega8A微处理器以及nRF24L01无线传输模块,用于采集来自PVDF传感器的振动信号以及实现信号调理和无线传输功能;后者包括Cortex-M3微控制器、SD卡和无线接收模块,用于实现传感器数据的接收和存储。实验结果表明,本系统能够实现准确的振动信号测量以及实时、可靠的数据传输。     

一种触觉感知与脑启发的触觉传感系统

触觉智能感知是当前研究的热点问题之一.然而,大规模触觉数据集的缺乏限制了机器人触觉感知领域的发展,解决问题的关键在于构建覆盖手掌的高时空分辨率触觉压力传感器系统.对此,构建一种脑启发的触觉传感系统(BITSS),以高时空分辨率对触觉压力信息进行获取,并实现基于脉冲事件的触觉感知.受皮肤触觉感受器启发,BITSS使用神经形态模型对触感压力信号进行脉冲编码,实现两种触觉感受器神经元的模拟.实验结果表明,BITSS模拟的神经放电活动可以解码出抓握状态的低维空间.在10种日常物体的分类任务中,基于脉冲事件的分类器分类精度达到94%,具有较快的执行速度,并验证了BITSS对触感压力信号的时空编码能力.     

一种仿生壶腹嵴的振动传感特性研究

为了研究人耳半规管中壶腹嵴的振动传感特性,本文采用表面对称电极含金属芯PVDF纤维(SMPF)传感器,代替人体纤毛细胞感受器,并模仿人体壶腹嵴的结构,设计制备了一种仿生壶腹嵴。根据压电方程和振动理论,建立了仿生壶腹嵴的振动传感理论模型。搭建了实验系统,测试了仿生壶腹嵴的振动传感功能。实验结果表明,仿生壶腹嵴在液体压力作用下可以产生相应的变形,而通过SMPF的输出电荷信号,可以感知仿生壶腹嵴受到的振动激励,包括正弦与冲击振动的波形、频率和幅值。实验结果验证了理论模型,同时验证了人体半规管中,壶腹嵴具有振动感知的能力和作用。     

表面四电极含金属芯压电纤维的冲击振动传感特性研究

模仿昆虫毛发感受器的结构和功能,设计制备了一种能测量外部振动的表面四电极含金属芯压电纤维(FMPF)冲击振动传感器.采用干压成型法制备了含铂金芯的压电陶瓷纤维胚体,经过高温烧结、涂镀表面电极、高温极化后,制成FMPF传感器.基于压电方程和振动理论,建立了悬臂梁结构的FMPF冲击振动传感器的理论模型,分析了传感信号与冲击振动角度和幅值的关系.把FMPF固定在基体上,搭建了实验系统,测试了FMPF对冲击振动的响应,验证了理论模型.结果表明,FMPF的传感信号和冲击振动的幅值成线性关系,和方向成"8"字形关系.得出了FMPF传感器能够测量冲击振动幅值和方向的结论.     

Piezoelectric properties of vinylidene fluoride oligomer for use in medical tactile sensor applications

The piezoelectric effect of vinylidene fluoride (VDF) oligomer was evaluated with respect to its medical use as a new tactile sensor. VDF oligomer is a new substance that has a smaller number of VDF units and a lower molecular weight than poly(vinylidene fluoride) (PVDF); among the organic ferroelectrics, it has the largest reported remanent polarization. In this work, the performance of a prototype sensor device based on this material was evaluated. The piezoelectric coefficient of VDF oligomer was found to be greater than that of P(VDF/TrFE) copolymer; a film composed of VDF oligomer was thin and uniform. Based on the experimental results, possible applications of VDF oligomer in medical tactile sensors are discussed. This study confirms that VDF oligomer is a promising ferroelectric material for use in tactile sensors.     

Object imaging with a piezoelectric robotic tactile sensor

A two-dimensional, electrically multiplexed robotic tactile sensor was realized by coupling a piezoelectric polyvinylidene fluoride (PVDF) polymer film to a monolithic silicon integrated circuit (IC). The IC incorporates 64 sensor electrodes arranged in a symmetrical 8×8 matrix. Each electrode occupies a 400×400 μm square area, and they are separated from each other by 300 μm. A 40-μm-thick piezoelectric PVDF polymer film was attached to the electrode array with an electrically nonconductive methane adhesive. The response of the tactile sensor is linear for loads spanning 0.8-135 grams-of-force (gmf) (0.00-1.35 Newtons (N)). The response bandwidth is 25 Hz, the hysteresis level is tolerable, and, for operation in the sensor's linear range, taxel crosstalk is negligible. The historically persistent stability and response reproducibility limitation associated with piezoelectric-based tactile sensors has been solved by implementing a novel pre-charge voltage bias technique to initialize the pre- and post-load sensor responses. A rudimentary tactile object image measurement procedure for applied loads has been devised to recognize the silhouette of a sharp edge, square, trapezoid, isosceles triangle, circle, toroid, slotted screw, and cross-slotted screw     

Tactile sensing and control of robotic manipulation

—This paper reviews the current state of the art and predicts the outlook in robotic tactile sensing for real-time control of dextrous manipulation. We begin with an overview of human touch sensing capabilities and draw lessons for robotic manipulation. Next, tactile sensor devices are described, including tactile array sensors, force-torque sensors, and dynamic tactile sensors. The information provided by these devices can be used in manipulation in many ways, such as finding contact locations and object shape, measuring contact forces, and determining contact conditions. Finally, recent progress in experimental use of tactile sensing in manipulation is discussed, and future directions for research in sensing and control are considered.     

通过PVDF阵列测量体积位移的实验研究

针对目前PVDF体积位移传感器的研究主要集中在经典边界条件(如简支、固定、自由等)、需要预知精确的边界条件等不足,提出通过伪逆方法结合Tikhonov正则化方法设计振动梁在任意未知边界条件下的压电式体积位移传感器的通用设计模型。以一未知边界条件的振动梁为例,用一组PVDF阵列测量其体积位移。在该梁表面均匀粘贴一组相同形状的矩形PVDF薄膜,然后通过所提出的新方法设计这组PVDF输出信号的加权系数,从而得到体积位移。实验结果表明这种传感器设计方法是可行的,并且不需要预知振动梁的边界条件或模态信息。     

SmartTouch: electric skin to touch the untouchable

Augmented haptics lets users touch surface information of any modality. SmartTouch uses optical sensors to gather information and electrical stimulation to translate it into tactile display. Augmented reality is an engineer's approach to this dream. In AR, sensors capture artificial information from the world, and existing sensing channels display it. Hence, we virtually acquire the sensor's physical ability as our own. Augmented haptics, the result of applying AR to haptics, would allow a person to touch the untouchable. Our system, SmartTouch, uses a tactile display and a sensor. When the sensor contacts an object, an electrical stimulation translates the acquired information into a tactile sensation, such as a vibration or pressure, through the tactile display. Thus, an individual not only makes physical contact with an object, but also touches the surface information of any modality, even those that are typically untouchable.