波纹梁夹持型双平行四边形柔性机构性能分析

为解决传统双平行四边形柔性机构中二级运动平台欠约束问题,设计了一种波纹梁夹持型对称双平行四边形柔性机构.首先,提出了一种基于正弦曲线的波纹梁结构,并将其安装在对称双平行四边形机构的2个二级平台之间;其次,建立了机构静力学解析模型,并利用拉格朗日方程建立了动力学模型;最后,利用有限元和实验方法对其静、动力学性能进行了仿真...     

Single contact optical beam induced currents

Semiconductor industry is continuously experiencing shrinking device features and a tremendous increase in the number of transistors in an integrated circuit (IC). The application of the optical beam induced currents (OBIC) technique in ICs is more difficult and mainly limited to a few transistors near the input–output pins of an IC. The single contact optical beam induced currents (SCOBIC) is a new device and failure analysis technique, that makes it possible to perform the similar OBIC technique on many transistor including internal junction on an IC. This is done by connecting the substrate or power pins of an IC circuit to the current amplifier. In contrast, in the OBIC technique, only the junction directly connected to the current amplifier is imaged. The implementation of the SCOBIC approach is discussed and experimental results which demonstrates the SCOBIC approach is presented. Application of the SCOBIC technique from the backside of an IC, which further enhances the technique, is also discussed.     

仿生柔性触角形状感知光纤传感方法研究

为解决智能机器人仿生柔性触角形状感知问题,研究柔性光纤传感方法。建立光纤触觉传感器三维模型,推导出柔性触角探测物体形状的曲率计算公式,建立柔性触角形状传感系统,实验研究光纤布拉格光栅作为传感元件的可行性,分析柔性仿生触角标定误差,得到仿生柔性触角弯曲导致光纤光栅中心波长漂移量与形状曲率的关系,拟合曲线与实际曲线之间的参数偏差小,验证了仿生柔性触角形状光纤传感技术可行性。研究结果表明,光纤传感方法可实现仿生柔性触角形状感知,在智能机器人领域具有应用前景。     

Vision-based active sensor using a flexible beam

Proposes a vision-based active sensing system, termed vision-based active antenna. This is composed of a camera, a flexible beam whose force-deformation characteristic is known, and an actuator for rotating the beam. The camera observes the beam deformation, including the contact information, while the beam is in contact with an object. By solving a set of equations based on the information acquired through the camera, the sensor can detect the contact location, the contact force, and the stiffness of the object, even though the contact point is hidden by occlusion. For two particular versions, we show some experimental results to verify the basic idea     

A cost-effective flexible MEMS technique for temperature sensing

A simplified, cost-effective flexible micro-electronic-mechanical systems (MEMS) technology has been developed for realizing a temperature-sensing array on a flexible polyimide substrate. The fabrication technique utilized liquid polyimide to form flexible film on the rigid silicon wafer using a temporary carrier during the fabrication. The platinum thin film is employed as temperature sensitive material and 8×8 temperature-sensing arrays were micromachined on the polyimide, from which the silicon wafer carrier was removed at the end of fabrication. The platinum thin film temperature sensor exhibits excellent linearity and its temperature coefficient of resistance reaches 0.00291 °C⁻¹. Because of the effective thermal isolation, the flexible temperature sensors show a high sensitivity of 1.12 Ω/°C at 10 mA to the constant drive current. The flexible MEMS technology based on liquid polyimide enables the development of flexible, compliant, robust, and multi-modal sensor skins for many other important applications, such as robotics, biomedicine, and wearable microsystems.     

Electron beam sensing of surface elastic waves

A method of readout of elastic surface waves by means of an electron beam is described. The signal detected by the beam is obtained directly in the form of the envelope of an RF pulse at a carrier frequency of 6 MHz.     

柔性梁振动控制系统设计

采用压电自感知执行器作为传感器和执行器,对柔性悬臂梁的振动情况进行研究,建立柔性悬臂梁系统的动力学方程,通过模态分析压电结构对柔性悬臂梁振动主动控制的原则和方法。利用最优控制理论得到对振动进行计算得到的最优控制信号来抑制悬臂梁的振动,完成对振动进行控制的目的。     

Transparent and flexible organic field-effect transistor for multi-modal sensing

Multi-functional devices having responsiveness to multiple physical stimuli, mechanical flexibility and optical transparency are of great interest in applications for human-machine interfaces. Here we demonstrate transparent and flexible organic field effect transistor (tf-OFET) devices with multi-modal sensing capability of detecting infrared (IR) light, pressure, and strain simultaneously. The multi-modal sensing layer with piezoelectricity and pyroelectricity was directly integrated into OFETs as the gate dielectric so that a new type of multi-modal sensing device with simple structure having possibility of increasing the sensor cell density can be easily fabricated. For decoupling of pyro- and piezoelectric responses in a single device under simultaneous stimulations of IR exposure and strain, an approach of determining two input stimuli by separating the polarization changes inside the gate dielectric (V_o) and the modulation in the product of effective field-effect channel mobility and gate capacitance (μC). The high sensitivity of the devices to IR from human body may also enable the devices to be applied for the realization of artificial intelligence that contacts directly with human body such as artificial e-skin, biomedical monitoring, and tactile sensing.     

Focused ion beam contact to non-volatile memory cells

Electrical characterization of non-volatile memory cells has been performed. A focused ion beam (FIB) contact procedure is presented that allows to contact the floating gate.Calculations and measurement results on an exemplary floating gate memory cell show intact cell structure with limited retention time after FIB modification. The presented procedure allows the measurement and control of the previously unavailable floating gate current and voltage.     

End-point vibration sensing of planar flexible manipulators through visual servoing

A visual servoing approach to the control of planar flexible robotic manipulators is adopted in this paper, based on the composite control theory, where the camera sensor is used together with the strain gauge measurements, to estimate the tip deformation. A fast Kalman filter, built on an integral manifold approximation of the manipulator model, can be used to fuse in the most effective way the measurements coming from different sensors, each one perturbed by its own noise. As a consequence, the signal to noise ratio of the deformation measurements can be effectively improved. A difficulty however arises in deriving a linear relation between the camera output and the state variables: the specific contribution of this paper is the derivation of such a linear relation in the fast time scale. Simulation results based on a two link planar flexible manipulator show the potential of the proposed approach to gain a more effective suppression of the tip vibrations, while an experimental example demonstrates its practical feasibility.     

Ion beam mixing for ohmic contact formation ton-Type GaAs

Electrical contacts have been formed on n-type GaAs (1.8 x 10¹⁸ carriers cm⁻³) using evaporated layers of 26 nm Ge/18 nm Ni or 40 nm Ge, with bombardment by 100-140 keV Se⁺ ions. After bombardment, the samples were annealed and the contact areas were subsequently coated, by evaporation, with Au for the Ge/Ni contacts or Ni + Au for the Ge contacts and then subjected to further thermal annealing. The objective is to induce ion beam mixing between Ni-Ge-GaAs or Ge-GaAs whilst simultaneously forming a heavily doped n-type region beneath the contact. The ion beam processing has been carried out for doses of 10¹⁴−10¹⁶ cm⁻² at temperatures ranging from 300-723K, followed by annealing at 693K for 120s for the Ge/Ni contacts and up to 1143K for the Ge contacts. In order to separate the doping effects from the ion beam mixing, bombardments were also undertaken using Kr⁺ ions. The specific contact resistance has been measured and the contacts further analysed using Auger depth profiling and RBS analysis. The contact morphology has been determined by SEM measurements.     

pH sensing reliability of flexible ITO/PET electrodes on EGFETs prepared by a roll-to-roll process

In this work, indium tin oxide (ITO) layers were deposited by radio frequency sputtering using a roll-to-roll process on flexible polyethylene terephthalate substrates as pH-sensing electrodes of extended gate field effect transistors (EGFETs). When the pH sensitivity of EGFETs for ITO layers with different sheet resistances was compared, a higher sensitivity was found for samples with a lower sheet resistance (100 Ω/□), and a reliability evaluation was carried out for this condition. The average sensitivity was 50.1 mV/pH, as measured from pH 2 to pH 12. Over three additional runs, the standard variation of the average sensitivity was found to be ±1.7 mV/pH. The tolerance to light is high; the samples were measured in dark and light conditions, and a difference of only 0.6 mV was observed. The temperatures available for measurement are 25–40 °C. Up to this point, the behavior of samples stored in dry conditions has been found to persist for more than 55 days.     

基于PDMS柔性支撑材料的磁敏感加速度传感装置

针对低频加速度信号的高灵敏检测,论文设计了一种基于PDMS柔性支撑材料的磁敏感加速度传感装置。研究了永磁体质量块周围磁场的分布情况,通过有限元仿真的方法对PDMS材料制备成的薄膜支撑结构在不同载荷下进行应力分析。搭建了基于PDMS柔性支撑材料的磁敏感加速度传感装置,并采用静态测试的方式对加速度传感装置的灵敏度进行了分析,得到的灵敏度为4.68 Gauss/g。最后对装置的固有频率以及能实现的检测分辨率进行了测试分析,结果显示固有频率为10 Hz,可以实现的检测分辨率为8.57 μg。     

机器人柔性触手形状的光纤传感及重构方法

为了解决机器人与外界交互时形状感知的需求,本文提出了一种基于FBG的用于解决机器人触手形状感知的方法。采用无粘结剂的形式将光纤光栅植入柔性硅胶片中固定,当柔性硅胶片紧贴所测物体表面时,硅胶片发生的形状变化将带动植入光纤的形状变化。通过光纤波长漂移量和弯曲曲率的关系,结合曲面重构算法构建出所测物体的表面形状,同时对柔性传感器的灵敏度进行了分析。实验证明了形状感知系统的可行性及稳定性,其灵敏度为65.822 pm/m-1,空间分辨率为3 cm,测量误差在2.9 %左右。该传感器结构简单,抗干扰性能良好,可通过改变光纤植入的深度及光栅之间的距离调节其灵敏度和空间分辨率以适应不同的情景,为执行机器人触手形状感知提供了参考。     

低轨卫星星座动态波束关闭算法

针对低轨多波束卫星星座网络中空间段卫星对地覆盖不均匀导致某些区域相对密集,造成严重的波束间干扰与不必要的波束资源开销等问题,提出了在满足覆盖等要求下的波束关闭算法。以多波束低轨星座网络为研究对象,分析并建立了低轨星座网络波束关闭的最优化问题,进而分析并论证了该问题的NP完全属性,给出了探索式求解方法。以共计3 168个波束的铱星星座网络为仿真场景,仿真分析了所提出的探索式波束关闭算法。仿真结果表明,所提算法仅需要1 913个波束即可实现对全球区域的连续覆盖,降低了39.61%的波束资源开销。     

Optical phase-front inscription over optical fiber end for flexible control of beam propagation and beam pattern in free space

We report a novel compact all-fiber technique to control the beam propagation and beam pattern in free space. By coating an azo-polymer thin film layer on the optical fiber end surface, various surface relief grating (SRG) structures were inscribed over the film using a single step direct exposure of interference patterns to form a novel organic/inorganic composite fiber optics beam shape converter. The linear and concentric SRGs were experimental characterized along with numerical simulations.     

A flexible temperature sensing finger using optical fiber grating for soft robot application

Bionic perception, especially temperature-aware, is one of the important issues in soft robots research. This paper presents a method to implant temperature sensor network into soft robot finger by using optical fiber gratings. For avoiding strain disturbance, a dedicated metal tube is designed to package and protect the optical fiber gratings. For implanting the sensors firmly, a solution using two kinds of adhesive is proposed. The prototype is calibrated in high precision temperature bath and then measured under different temperatures and different bending conditions, respectively. The experimental results are compared with electronic temperature sensor (PT100 thermal resistance), which verifies the accuracy and repeatability of the design. With the dedicated coating and adhesive solution, the proposed temperature sensor network is suitable for implanting into soft robots for the temperature-aware ability.     

基于重叠多光栅的动态应变传感特性研究

利用重叠多光纤布拉格光栅(FBG)反射谱的时间同 步性,实现了动态或静态应变信号的高速传感与解调。给出了基于光纤F-P 可调谐滤波器(FFP-TF)的重叠多FBG解调系统及其时域重构的实现方法,重叠多FBG在FFP- TF 三角波扫描电压与动态应 变信号测量时产生时域上等间隔分布的传感脉冲,解调系统采用质心法硬件解算并结合平滑 滤波的方法可满足速度与解调精 度的同时测量需要。在重叠双FBG与500Hz FFP-TF扫描速率条件下 可产生2kHz的传感脉冲,动态应变信号的测量 带宽相对于单FBG解调系统提高了4倍,静态条件下的波长偏移小于±4pm。给出了影响重叠多FBG动态应变信号解调结果失真度的影响因素。     

压电智能应用于柔性悬臂梁振动控制系统研究

基于模糊控制的振动控制方法,针对柔性悬臂梁,设计了相应振动控制器。采用电桥电路法分离出压电自感知执行器的感知信号,通过传感器将采集进来的信号,由最优控制理论离线计算得到理论输出值。并将理论输出值与对应的系统输入值对应起来,从而建立拥有最优解的模糊控制规则表。通过传感器采集系统状态并经过处理得到输出信号,作用于执行器上对柔性梁的振动进行抑制。仿真结果表明,采用的控制器对于改善振动快速控制是非常有效的。