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81.
Flexible piezoresistive films, such as, carbon black/polydimethylsiloxane (C-PDMS) composites, are often used as skin analogs and integrated into complex array sensors for tactile sensing. The uniformity of the sensor characteristics heavily depends on the homogeneity of the composite. Therefore, the ability to locally characterize a film that will be integrated into a complex force sensor could be critical. Here, a method to characterize the local sensitivity of flexible piezoresistive films is presented. Using a conductive sphere, which was chosen over a flat probe to eliminate misalignment issues, the surface of a thin film composite is indented to characterize the change in resistivity in terms of average strain. Experiments were performed with 15 and 18 wt% carbon black C-PDMS films of varying thickness. The contact radius of the probe with the piezoresistive film was estimated using the Johnson-Roberts-Kendall contact theory. Theoretical contact area estimates were found to agree with contact radius measurements carried out using optically transparent PDMS films observed through an optical microscope. Results show that C-PDMS with 15 wt% carbon black exhibit a higher rate if change of resistivity and gauge factor than films of same thickness with 18 wt% carbon black. On the other hand, thicker films exhibit higher gauge factors for the two tested carbon black contents. Tests carried out at multiple locations yielded consistent sensitivity values, making these types of composites suitable for array type force sensors. 相似文献
82.
Cavity pressure is one of the best indicators of injection molding conditions and thus has been used for quality prediction in the injection molding process. Also, the repeatability of the cavity pressure profile at each shot indicates the consistency of the part quality, which is easily affected by environmental changes, such as barrel temperature. To maintain quality consistency (such as part weight and geometrical dimensions) during mass production, this study proposed a novel method of the holding pressure adjustment to control the deviation in the cavity pressure distribution during each shot. Injection molding of a thin-walled dumbbell-shaped sample was performed to verify the proposed process, which proved the feasibility of this method for suppressing the influence of the barrel temperature changes on part quality. 相似文献
83.
Natural rubber is one of the most potential electro-active polymers for sensors, actuators, and energy harvesting applications. Enhancing the characteristic properties of polymers by reinforcing with fillers that possess multifunctional attributes have attracted considerable attention. In the present study, barium titanate reinforced natural rubber composite is prepared by using two-roll mill mixing. Afterwards, mechanical, electrical, and electromechanical properties of the composites are extensively analyzed by reinforcing different amounts of barium titanate into the matrix of natural rubber. The fabricated dielectric composite shows excellent properties such as high dielectric constant, low dielectric losses, high dielectric breakdown strength, and extreme stretchability. It is observed that as the filler loading reaches the value of 11 parts per hundred rubber (phr), maximum agglomeration of the particles occurs. Maximum stretchability and highest ratio of dielectric constant to elastic modulus are obtained at 8 phr of barium titanate fillers and at the loading, a maximum actuation strain of 11.24% is achieved. This study provides a simple, economical, and effective method for preparing enhanced mechanical, electrical, and electromechanical properties of natural rubber composites, facilitating the wide applications of dielectric materials as actuators and generators. 相似文献
84.
Photoresists play an increasingly important role in industrial fields like micro-electro mechanical systems, micromachining, and chip packaging. However, the traditional one-component photoresist is insulated, and additional steps are required to make it conductive, which complicates the process and limits its application. In order to solve the problem, we establish a one-step strategy to build conductive composite photoresist. Herein, graphene (GR) and silver nanowire (AgNW) are doped into SU-8 photoresist to fabricate a photo-patternable conductive composite. The composite photoresist is employed to make micro-patterns on an ITO electrode using photolithography, followed by electrochemical reduction of copper nanoparticles (CuNPs) to produce a nonenzymatic sensing coating. Experimental results prove that the response current of the obtained sensor is linearly related to the concentration of hydrogen peroxide in the range of 1–25 mM. The sensitivity and detection limit of the sensor are 41.8 μA mM−1 cm−2 and 9 μM, respectively. Moreover, excellent sensing performance including anti-interference, repeatability, and stability demonstrates the potential application of CuNPs/AgNW/GR/SU-8 composite material in electrochemical sensing. 相似文献
85.
Christian Hopmann Nadine Magura Nicolas Rozo Lopez Daniel Schneider Kai Fischer 《Polymer Engineering and Science》2021,61(5):1353-1367
Wet filament winding technology has been extensively used for the manufacture of rotationally symmetric parts made of fiber-reinforced plastics (FRP). As the design and modeling of FRP-parts require numerous assumptions, deviations between calculated and achieved mechanical properties are expected. One aspect that contributes to this discrepancy is the assumption of a homogeneous rectangular cross-section of the fiber-band. In this work, the fiber-band geometry in a wet-winding process of carbon fiber cylinders is analyzed. An Infrared-optical system for the detection of the fiber bandwidth and winding-angle is implemented. The influence of the winding speed and the resin temperature is analyzed. An image processing algorithm for the automatic measurement of the fiber's bandwidth and winding-angle is developed. Manual and adaptive gamma corrections are implemented to improve image quality. A parameter study for the suitable selection of image processing parameters is performed. 相似文献
86.
温室移动机器人运动控制器设计与实现 总被引:2,自引:0,他引:2
用运动控制器实现了移动机器人在非结构化、未知环境中的自主导航和定位。运动控制器由PIC单片机、运动控制模块、电机驱动模块、红外传感器模块、通讯模块以及相应的控制软件组成。利用两层前向BP神经网络实现多传器的信息融合。运动控制器在温室移动机器人上进行多次试验。试验结果表明,运动控制器和控制算法是可行的,并具:工程应用的前景。 相似文献
87.
In this article, we proposed a rapid and continuous process for the production of nanoporous coatings for functional applications.
Experiments following two statistical designs were implemented to screen and investigate the spraying parameters’ effects
on coating crystallinity and porosity in order to gain a better understanding. The spraying standoff distance, solution flow
rate and power were identified as having significant effects on coating porosity and crystallinity. The result yielded a peculiar
microstructure comprised of interpenetrating pores and layered structures with embedded pores. A deposition mechanism was
postulated to explain this microstructure. Ethanol gas sensors that are constructed from the coatings had comparable sensitivities
to those reported in the literature for thick-film coatings and had a maximum sensitivity near 200 °C.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
88.
89.
针对无人飞行器视觉定位结果存在较大时延而影响飞行器运动状态估计精度的问题,提出了一种基于多传感器数据融合的实时运动估计方法.首先,利用机载惯性测量元件(IMU)提供的姿态信息优化单目视觉定位算法,使得视觉定位结果的时延减小.然后,在利用卡尔曼滤波器估计飞行器运动状态的过程中,考虑了视觉定位结果的时延,利用加速度信息进行时延补偿.最终得到实时的高精度运动估计结果.在自主研制的四旋翼飞行器系统上对本文提出的方法进行了验证.通过与不考虑时延的方法的结果以及真实数据进行比较,证明了本方法的有效性. 相似文献
90.