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Actuator-Control Circuit Based on OTFTs and Flow-Rate Estimation for an All-Organic Fluid Pump
摘要： In this paper, we report the design of an organic thin-film transistor (OTFT) driver circuit for the actuator of an organic fluid pump, which can be integrated in a portable-size fully-organic artificial lung. Compared to traditional pump designs, lightness, compactness and scalability are achieved by adopting a creative pumping mechanism with a completely organic-material-based system concept. The transportable fluid volume is verified to be flexibly adjustable, enabling on-demand controllability and scalability of the pump’s fluid-flow rate. The simulations, based on an accurate surface-potential OTFT compact model, demonstrate that the necessary driving waveforms can be efficiently generated and adjusted to the actuator requirements. At the actuator-driving-circuit frequency of 0.98 Hz, an all-organic fluid pump with 40 cm length and 0.2 cm height is able to achieve a flow rate of 0.847 L/min, which satisfies the requirements for artificial-lung assist systems to a weakened normal lung.
关键词： organic thin-film transistor,fluid volume,organic actuator,organic circuit,HiSIM-organic model,artificial lung,circuit simulation
更新于2025-09-09 09:28:46
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On-Chip Platform for Slack-Free Carbon Nanotube Resonators
摘要： This work describes an on-chip integrated micro-actuator device for slack-free carbon nanotube (CNT) resonators, improving frequency tunability and Q factor and to study non-linear mode interaction. The device fabricated on SOI wafer with low thermal budget (<600 K) encompasses a restricted symmetrical out-of-plane vibration and a stiff in-plane electro-thermal actuator with a displacement of ~112 nm at 2.7 mW. This corresponds to 5.6% of strain for a 2 μm long suspended carbon nanotube. The in-plane mechanical resonance designed to be far from CNT resonances in MHz regime is measured at 209 kHz. The design is optimized for low power consumption, electrical and thermal isolation and is customized for dry transfer of CNTs.
关键词： carbon nanotube,micro-actuator,strain-sensor,resonator
更新于2025-09-09 09:28:46
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Applications of Piezoelectrics: Old and New
摘要： Piezoelectric materials convert electrical energy to mechanical energy and vice versa, resulting in observed properties that are electromechanically coupled. When a piezoelectric is deformed, that mechanical energy is transformed to electrical energy, which is known as the direct piezoelectric effect. When the reverse occurs, and an electric field is applied, the material physically deforms, resulting in the converse piezoelectric effect. Therefore, piezoelectric materials can be used in both sensor and actuator applications. The magnitude of the piezoelectric response is often expressed as the longitudinal piezoelectric coefficient, d33. When measuring the direct piezoelectric effect, d33 is the polarization generated per unit of mechanical stress, where the field and stress are along the same direction. In the converse effect, d33 is the induced mechanical strain per unit of electric field applied, with the field and stress also in the same direction. Another measure of effectiveness of a piezoelectric is called the electromechanical coupling factor, k. This value expresses the efficiency of conversion from mechanical to electrical energy or vice versa.
关键词： actuator applications,electromechanical coupling factor,sensor applications,direct piezoelectric effect,Piezoelectric materials,converse piezoelectric effect
更新于2025-09-09 09:28:46
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Robust precision motion control of piezoelectric actuators using fast nonsingular terminal sliding mode with time delay estimation
摘要： Background: Piezoelectric actuators are widely used in many micro/nano-manipulation applications, but their positioning accuracy are badly affected by their inherent nonlinear hysteresis and creep. To solve this problem, this paper presents a new robust motion-control method for piezoelectric actuators with fast nonsingular terminal sliding mode based on time delay estimation. Method: The proposed controller needs no detailed information about the hysteresis and other nonlinearities of the system, leading to a simple and model-free characteristic due to the time delay estimation and ensures fast convergence and high tracking accuracy thanks to the nonsingular terminal sliding-mode surface and fast terminal sliding mode -type reaching law. A robust exact differentiator is adopted to estimate the velocity and accelerationinformation online, and it overcomes the limitation of only available position measurements. The finite-time convergence and stability of the closed-loop system are proved by using a Lyapunov function. Results: Experimental results show that the proposed control strategy has faster convergence and higher tracking precision compared with a traditional time delay control. Conclusion: The proposed control strategy can be widely used as an effective control method for high-precision motion control of piezoelectric actuators.
关键词： finite-time convergence,Piezoelectric actuator,terminal sliding mode,time delay estimation
更新于2025-09-09 09:28:46
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Evaluating the Reduction of Stress Intensity Factor in Center-Cracked Plates Using Piezoelectric Actuators
摘要： Active repairs using smart materials such as piezoelectric actuators can play a significant role in reducing the crack damage propagation in engineering structures. This study analytically and numerically investigated the active repair of center-cracked plates using piezoelectric actuators. First, the stress intensity factor (SIF) for a center-cracked plate due to stress produced by a piezoelectric actuator is analytically modeled. This analytical model is obtained by applying the method of weight functions. In the second step, the solution is found for the center-cracked plate due to external loading from known linear elastic fracture mechanics. These solutions are then superimposed, taking into account the superposition principle to yield the total stress intensity factor for the integrated piezoelectric actuator to the center-cracked plate. Finally, the proposed theoretical model is verified by finite element simulation. The results indicated that the relative errors of the analytical model and the FEA results are less than 5% in all the cases studied in this paper.
关键词： fracture mechanics,stress intensity factor,active repair,piezoelectric actuator
更新于2025-09-09 09:28:46
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Discharge characteristic and flow control experiment for pneumatic actuator of dielectric barrier discharge multistage plasma
摘要： Test and diagnosis of the characteristics of the air flow induced by the pneumatic actuation of the plasma are the important basis for the plasma flow control. In order to well understand the electrical characteristics of the pneumatic actuation of the plasma and the influence of the actuation voltage amplitude and the phase on the induced flow characteristics, the dielectric barrier discharge actuators symmetrically distributed were selected for the experimental research. The experiment result shows that the discharge form of the actuators symmetrically distributed is filamentary discharge, uniformly occurring around the high-voltage electrodes, and this is different from the discharge picture of the actuators asymmetrically distributed; when the voltage applied on the high-voltage electrode near to the actuators has the same amplitude and phase, the induced directional jet flow is vertical to the actuator surface, and the speed is at the order of meter per second; the change of the amplitude or phase of the voltage applied on the high-voltage electrode of the actuator can induce a jet flow towards the upper left or the upper right, but cannot effectively increase the induced airflow velocity.
关键词： Dielectric barrier,flow control,pneumatic actuator,discharge characteristic
更新于2025-09-09 09:28:46
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Experimental Application of Piezoelectric Actuator-Driven Pulsed Water Jets in Retinal Vascular Surgery
摘要： To report on the effectiveness and safety of an ophthalmic piezoelectric actuator-driven pulsed water jet (ADPJ) system adapted for intraocular use. Methods: First, we determined the highest ADPJ flow rate that did not cause an unsafe rise in intraoperative intraocular pressure (IOP) in rabbits (n ? 4). Next, we determined the most effective ADPJ frequency (in hertz) at that flow rate. Finally, we visualized the ADPJ stream, measured its pressure, and determined the minimum voltage and distance between the ADPJ needle and retinal veins to induce intravenous displacement of the blood column (DBC) through massage of the outer retinal vessels (n ? 3) while not causing retinal tearing or hemorrhage. Results: We found that a 0.05 mL/min ADPJ flow rate caused IOP to rise above 40 mm Hg after 1 minute, but that at 0.025 mL/min, IOP stayed below 40 mm Hg even after 3 minutes. Moreover, we found that a 0.025 mL/min ADPJ stream was stable at a pulse frequency of 10 Hz and that at this flow rate/frequency the ADPJ pressure was closely correlated with the applied voltage (P , 0.001, r2 ? 0.9991). The minimum voltage and distance to achieve intravenous DBC without causing retinal tearing or hemorrhage were 40 V and 0.5 mm, respectively. Conclusions: With an appropriate flow rate and surgical time, ADPJ successfully induced massage of the retinal vessels and intravenous DBC while maintaining safe IOP and not causing retinal complications. Translational Relevance: The ADPJ system has promise as a safe and minimally invasive instrument for the intraocular surgical treatment of human retinal vascular diseases.
关键词： intraocular pressure,retinal complication,retinal vascular surgery,piezoelectric actuator-driven pulsed water jet,retinal vein occlusion
更新于2025-09-04 15:30:14
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Adaptive controllers for a piezoelectric actuator without and with discontinuity
摘要： This paper deals with the dynamics and adaptive control of a piezoelectric micro-electromechanical device without and with discontinuity. The modelling of the device with a discontinuity is carried out and its dynamics is studied using the bifurcation diagram to observe the regions of periodic and chaotic motions. The Lyapunov theory is used to design adaptive controllers to restore the prescribed dynamics of the system when it is subjected to a short variation of one of its parameters. The efficiency of the controllers is tested using numerical simulations.
关键词： backstepping control,piezoelectric actuator,adaptive control,discontinuity
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Millimetre-wave beam steerable leaky-wave antenna for 5G systems
摘要： A beam steerable Leaky-Wave antenna (LWA) is designed based on Partially Reflective Surface (PRS) and High Impedance Surface (HIS) materials for future millimetre-wave (mm-wave) mobile applications such as 5G. The antenna beam steering is obtained by changing the phase of reflection coefficient (S11) of the HIS through varying the separation between the HIS periodic array and ground layers. This is accomplished by employing direct current (DC) biased piezoelectric actuators (PEAs) on the ground layer. The antenna’s simulated S11 bandwidth (BW), beam scanning range and maximum gain at 54.5GHz are about 3GHz, 43° in H-plane and 13.7dBi, respectively.
关键词： Millimetre-wave antenna,Piezo-electric actuator,high gain antenna,Leaky-wave antenna
更新于2025-09-04 15:30:14
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Cardiomyocyte-Driven Structural Color Actuation in Anisotropic Inverse Opals
摘要： Biohybrid actuators composed of living tissues and artificial materials have attracted increasing interest in recent years because of their extraordinary function of dynamically sensing and interacting with complex bioelectrical signals. Here, a compound biohybrid actuator with self-driven actuation and self-reported feedback is designed based on an anisotropic inverse opal substrate with periodical elliptical macropores and a hydrogel filling. The benefit of the anisotropic surface topography and high biocompatibility of the hydrogel is that the planted cardiomyocytes could be induced into a highly ordered alignment with recovering autonomic beating ability on the elastic substrate. Because of the cell elongation and contraction during cardiomyocyte beating, the anisotropic inverse opal substrates undergo a synchronous cycle of deformation actuations, which can be reported as corresponding shifts of their photonic band gaps and structural colors. These self-driven biohybrid actuators could be used as elements for the construction of soft-bodied structural color robot, such as a biomimetic guppy with a swinging tail. Besides, with the integration of a self-driven biohybrid actuator and microfluidics, the advanced heart-on-a-chip system with the feature of microphysiological visuality has been developed for integrated cell monitoring and drug testing. This anisotropic inverse opal-derived biohybrid actuator could be widely applied in biomedical engineering.
关键词： cardiomyocyte,microfluidics,inverse opal,heart on a chip,structural color,actuator
更新于2025-09-04 15:30:14