- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Nano- and Microfabrication for Industrial and Biomedical Applications || Micromechanical transducers
摘要： Miniaturized micromechanical-based transducers are applied in many various scientific communities and industries. In this chapter we look into the basic concepts of this extensive and important category of devices using simple components as examples. Transducers come in such extreme diversity that a descriptive overview such as is provided by this book is best taken from the perspective of the user. One of the most easily understood definitions of transducers is that they convert energy from one form into another. This perspective also shows that there is no one single design rule. The designer needs to start from a range of actual conditions to realize the required transduction principle in a given application.
关键词： microfabrication,MEMS,Micromechanical transducers,actuators,sensors
更新于2025-09-23 15:21:01
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pH and Thermo Dual-Responsive Fluorescent Hydrogel Actuator
摘要： As one of the most important smart materials, fluorescent hydrogel actuators can produce both color and shape changes under external stimuli. In the present work, an effective approach to develop a novel fluorescent hydrogel actuator with pH and thermo dual responsiveness is proposed. Through incorporating pH-responsive perylene tetracarboxylic acid (PTCA), which is a typical fluorescent moiety with aggregation-caused quenching (ACQ) effect, into an anisotropic poly(N-isopropylacrylamide)–polyacrylamide (PNIPAm-PAAm) structure, the obtained hydrogel exhibits stable thermoresponsive shape deformation and switchable fluorescence performance upon a pH trigger. Therefore, fluorescence-quenching-based and actuation-based information can be revealed when exposed to UV light and immersed into warm water, respectively. Moreover, the thermoresponsive actuating behavior can be applied to further hide the fluorescence-quenching-based images. The present work may provide new insights into the design and preparation of novel stimuli-responsive hydrogel actuators.
关键词： anisotropic structures,hydrogel actuators,fluorescence quenching,shape deformation
更新于2025-09-23 15:21:01
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Lasera??Induced Graphene for Electrothermally Controlled, Mechanically Guided, 3D Assembly and Humana??Soft Actuators Interaction
摘要： Mechanically guided, 3D assembly has attracted broad interests, owing to its compatibility with planar fabrication techniques and applicability to a diversity of geometries and length scales. Its further development requires the capability of on-demand reversible shape reconfigurations, desirable for many emerging applications (e.g., responsive metamaterials, soft robotics). Here, the design, fabrication, and modeling of soft electro-thermal actuators based on laser-induced graphene (LIG) are reported and their applications in mechanically guided 3D assembly and human-soft actuators interaction are explored. Over 20 complex 3D architectures are fabricated, including reconfigurable structures that can reshape among three distinct geometries. Also, the structures capable of maintaining 3D shapes at room temperature without the need for any actuation are realized by fabricating LIG actuators at an elevated temperature. Finite element analysis can quantitatively capture key aspects that govern electrothermally controlled shape transformations, thereby providing a reliable tool for rapid design optimization. Furthermore, their applications are explored in human-soft actuators interaction, including elastic metamaterials with human gesture-controlled bandgap behaviors and soft robotic fingers which can measure electrocardiogram from humans in an on-demand fashion. Other demonstrations include artificial muscles, which can lift masses that are about 110 times of their weights and biomimetic frog tongues which can prey insects.
关键词： human-soft actuators interaction,laser-induced graphene,electrothermal actuators,3D assembly
更新于2025-09-23 15:19:57
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Multiband Fractal Metasurface with Linear to Linear and Linear to Circular Polarization Conversion
摘要： Mapping the brain centers that mediate the sensory-perceptual processing of visceral afferent signals arising from the body (i.e., interoception) is useful both for characterizing normal brain activity and for understanding clinical disorders related to abnormal processing of visceral sensation. Here, we report a novel closed-system, electrohydrostatically driven master–slave device that was designed and constructed for delivering controlled ?uidic stimulations of visceral organs and inner cavities of the human body within the con?nes of a 3T magnetic resonance imaging (MRI) scanner. The design concept and performance of the device in the MRI environment are described. In addition, the device was applied during a functional MRI (fMRI) investigation of visceral stimulation related to detrusor distention in two representative subjects to verify its feasibility in humans. System evaluation tests demonstrate that the device is MR-compatible with negligible impact on imaging quality [static signal-to-noise ratio (SNR) loss <2.5% and temporal SNR loss <3.5%], and has an accuracy of 99.68% for ?ow rate and 99.27% for volume delivery. A precise synchronization of the stimulus delivery with fMRI slice acquisition was achieved by programming the proposed device to detect the 5 V transistor–transistor logic (TTL) trigger signals generated by the MRI scanner. The fMRI data analysis using the general linear model analysis with the standard hemodynamic response function showed increased activations in the network of brain regions that included the insula, anterior and mid-cingulate and lateral prefrontal cortices, and thalamus in response to increased distension pressure on viscera. The translation from manually operated devices to an MR-compatible and MR-synchronized device under automatic control represents a useful innovation for clinical neuroimaging studies of human interoception.
关键词： automation,fMRI,electrohydrostatic actuation,visceral afferent processing,MR-compatible sensors and actuators
更新于2025-09-23 15:19:57
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Spatial Prediction of Undersampled Electromagnetic Fields
摘要： Pneumatic devices require tight tolerances to keep them leak-free. Specialized companies offer various off-the-shelf devices, while these work well for many applications, there are also situations where custom design and production of pneumatic parts are desired. Cost efficiency, design flexibility, rapid prototyping, and MRI compatibility requirements are reasons why we investigated a method to design and produce different pneumatic devices using a laser cutter from acrylic, acetal, and rubber-like materials. The properties of the developed valves, pneumatic cylinders, and stepper motors were investigated. At 4-bar working pressure, the 4/3-way valves are capable of 5-Hz switching frequency and provide at most 22-L/min airflow. The pneumatic cylinder delivers 48 N of force, the acrylic stepper motor 30 N. The maximum switching frequency over 6-m long transmission lines is 4.5 Hz, using 2-mm tubing. A MRI-compatible robotic biopsy system driven by the pneumatic stepper motors is also demonstrated. We have shown that it is possible to construct pneumatic devices using laser-cutting techniques. This way, plastic MRI-compatible cylinders, stepper motors, and valves can be developed. Provided that a laser-cutting machine is available, the described pneumatic devices can be fabricated within hours at relatively low cost, making it suitable for rapid prototyping applications.
关键词： pneumatic systems,Biopsy,magnetic resonance imaging,medical robotics,pneumatic actuators
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 58th Conference on Decision and Control (CDC) - Nice, France (2019.12.11-2019.12.13)] 2019 IEEE 58th Conference on Decision and Control (CDC) - Laser Sintering Control for Metal Additive Manufacturing by PDE Backstepping
摘要： The dynamic response of the pitch angle slows down when the pitch actuator of wind turbines fails, and the fault leads to ?uctuations in the generator speed and in the output power. According to identi?cation and analytical theories, a fault-tolerant control combined with fault estimation is proposed to solve this problem. The simpli?ed two-order transform function of the pitch actuator is transformed into the identi?cation equation by means of the Euler transformation method. Next, the time-varying natural frequency and the damping ratio of pitch actuators are regarded as gradual change and abrupt change parameters; these two parameters are estimated using the proposed sliding data window least squares-based iterative (SDW-LSI) identi?cation algorithm. The sliding data window length is adjusted when changes in the system parameters are detected. Then, according to analytical theory, a compensation equation is derived in the pitch actuator, and the estimated values are fed back to the compensation module to adjust the relations before and after fault occurrences in the pitch actuator to eliminate the effects caused by the pitch actuator failure. Finally, the feasibility of the SDW-LSI algorithm is validated by choosing the fault of high air content in the hydraulic oil.
关键词： Fault diagnosis,system identi?cation,wind power generation,fault tolerant,hydraulic actuators
更新于2025-09-23 15:19:57
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[IEEE 2019 24th Microoptics Conference (MOC) - Toyama, Japan (2019.11.17-2019.11.20)] 2019 24th Microoptics Conference (MOC) - Optimized LED-based Optical Wireless Power Transmission System Configuration for Compact IoT
摘要： The dynamic response of the pitch angle slows down when the pitch actuator of wind turbines fails, and the fault leads to ?uctuations in the generator speed and in the output power. According to identi?cation and analytical theories, a fault-tolerant control combined with fault estimation is proposed to solve this problem. The simpli?ed two-order transform function of the pitch actuator is transformed into the identi?cation equation by means of the Euler transformation method. Next, the time-varying natural frequency and the damping ratio of pitch actuators are regarded as gradual change and abrupt change parameters; these two parameters are estimated using the proposed sliding data window least squares-based iterative (SDW-LSI) identi?cation algorithm. The sliding data window length is adjusted when changes in the system parameters are detected. Then, according to analytical theory, a compensation equation is derived in the pitch actuator, and the estimated values are fed back to the compensation module to adjust the relations before and after fault occurrences in the pitch actuator to eliminate the effects caused by the pitch actuator failure. Finally, the feasibility of the SDW-LSI algorithm is validated by choosing the fault of high air content in the hydraulic oil.
关键词： Fault diagnosis,system identi?cation,wind power generation,fault tolerant,hydraulic actuators
更新于2025-09-23 15:19:57
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Light-Induced Shape Morphing of Thin Films
摘要： Shape transformation of thin two-dimensional sheets into three-dimensional structures using light is of great interest for remotely-controlled fabrication, surface modulation, and actuation. Over the last few decades, significant efforts have been made to develop materials systems incorporating photochemical or photothermal elements to drive deformation in response to illumination. However, the full extent of the interplay between chemistry, optics, and mechanics in these materials is poorly understood. In this Review, we introduce principles of shape morphing in these systems by considering the underlying physics of photo-induced stresses and how these have been used in recent literature. In addition, we provide a critical overview of the important design characteristics of both photochemical and photothermal system and offer our view on the open opportunities and challenges in this rapidly growing field.
关键词： soft materials,thin film mechanics,Photomechanics,polymers,light responsive materials,shape morphing,actuators
更新于2025-09-19 17:15:36
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D controller for precise nanopositioning in the presence of hardware-induced constant time delay
摘要： The fast and accurate tracking of periodic and arbitrary reference trajectories is the principal goal in many nanopositioning applications. Flexure-based piezoelectric stack driven nanopositioners are widely employed in applications where accurate mechanical displacements at these nanometer scales are required. The performance of these nanopositioners is limited by the presence of lightly damped resonances in their dynamic response and actuator nonlinearities. Closed-loop control techniques incorporating both damping and tracking are typically used to address these limitations. However, most tracking schemes employed use a first-order integrator whereas a triangular trajectory commonly used in nanopositioning applications necessitates a double integral for zero-error tracking. The phase margin of the damped system combined with the hardware-induced delay deem the implementation of a double-integrator unstable. To overcome this limitation, this paper presents the design, analysis and application of a new control scheme based on the structure of the traditional Two-Degrees-of-Freedom PID controller (2DOF-PID). The proposed controller replaces the integral action of the traditional 2DOF-PID with a double integral action (2DOF-PI2D). Despite its simplicity, the proposed controller delivers superior tracking performance compared to traditional combined damping and tracking control schemes based on well-reported designs such as positive position feedback (PPF), Integral resonant control (IRC), and Positive Velocity and Position Feedback (PVPF). The stability of the control system is analyzed in the presence of a time delay in the system. Experimental results validating the efficacy of the proposed chattering-free control of a piezo-driven nanopositioning system are included.
关键词： Vibration,Piezoelectric actuators (PEAs),Precision Motion control
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Indoor and Outdoor Test Results for "DUSST", a Low-Cost, Low-Maintenance PV Soiling Sensor
摘要： Pneumatic devices require tight tolerances to keep them leak-free. Specialized companies offer various off-the-shelf devices, while these work well for many applications, there are also situations where custom design and production of pneumatic parts are desired. Cost efficiency, design flexibility, rapid prototyping, and MRI compatibility requirements are reasons why we investigated a method to design and produce different pneumatic devices using a laser cutter from acrylic, acetal, and rubber-like materials. The properties of the developed valves, pneumatic cylinders, and stepper motors were investigated. At 4-bar working pressure, the 4/3-way valves are capable of 5-Hz switching frequency and provide at most 22-L/min airflow. The pneumatic cylinder delivers 48 N of force, the acrylic stepper motor 30 N. The maximum switching frequency over 6-m long transmission lines is 4.5 Hz, using 2-mm tubing. A MRI-compatible robotic biopsy system driven by the pneumatic stepper motors is also demonstrated. We have shown that it is possible to construct pneumatic devices using laser-cutting techniques. This way, plastic MRI-compatible cylinders, stepper motors, and valves can be developed. Provided that a laser-cutting machine is available, the described pneumatic devices can be fabricated within hours at relatively low cost, making it suitable for rapid prototyping applications.
关键词： pneumatic systems,Biopsy,magnetic resonance imaging,medical robotics,pneumatic actuators
更新于2025-09-19 17:13:59