Hip joint moments during walking are the key foundation for hip exoskeleton assistance control. Most recent studies have shown estimating hip joint moments instantaneously offers a lot of advantages compared to genera...
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To address the precision limitation of traditional thermal models and the computational inefficiency of electromagnetic-thermal coupling finite element models, this work proposes a multidimensional correction-based el...
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ISBN:
(数字)9798350370607
ISBN:
(纸本)9798350370614
To address the precision limitation of traditional thermal models and the computational inefficiency of electromagnetic-thermal coupling finite element models, this work proposes a multidimensional correction-based electromagnetic-thermal coupling design optimization method for electric machines. Firstly, this method corrects the sensitive parameters in the analytical lumped parameters thermal network model (LPNM) based on prior information from historical experimental data to ensure the accuracy for thermal performance analysis. Subsequently, to enhance computational efficiency, a large number of low-fidelity (LF) samples are obtained using the corrected thermal model in a serial electromagnetic-thermal field calculation manner, complemented by a small number of high-fidelity (HF) samples obtained from the electromagnetic-thermal coupling simulation model. Then, by employing a transfer learning technique, the data information from the low- to high-fidelity sample sets is comprehensively utilized to train a multi-fidelity (MF) surrogate model for the final optimization. The proposed method applied to a high-torque-density aerospace propulsion permanent magnet synchronous motor (PMSM) with short-term strong overload capability, it not only significantly improves the accuracy of LPNM, but also reduces the training sample acquisition time by over 50% under the same model accuracy. Finally, a prototype is tested to validate the effectiveness of the proposed method.
SEMG signal is widely used and explored in control strategies of powered assistive human-robot interaction systems due to its non-invasive nature and ability to estimate motion intention well. However, prolonged use o...
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Cell culture in vitro is essential for drug screening, disease modeling, and stem cell-related research. Previous studies have indicated that two-dimensional (2D) cellular environments can significantly differ from ph...
Cell culture in vitro is essential for drug screening, disease modeling, and stem cell-related research. Previous studies have indicated that two-dimensional (2D) cellular environments can significantly differ from physiological cells in vivo, leading to a high failure rate when translating therapeutics developed in 2D cell models to clinical applications. Therefore, there is a strong focus on developing three-dimensional (3D) cell culture techniques that more closely mimic in vivo cell microenvironments. These techniques hold great promise for enhancing precision in drug discovery and tissue regeneration. In this study, we introduce a novel microfluidic technique that utilizes droplets to fabricate hydrogel microspheres, each exhibiting a unique internal morphology suitable for 3D cell culture applications. Specifically, we employed this method to cultivate human umbilical vein endothelial cells (HUVECs) within the interior canals of the hydrogel microspheres, forming monolayers on the surfaces of the spiral canals. This setup effectively mimicked the configurations of native blood vessels. Furthermore, we successfully demonstrated the fabrication of heterogeneous spheroids with spiral blood vessel lumens, which can be utilized to construct spiral vascularized bone tissue.
Engineered extracellular matrices(ECMs)that replicate complex in-vivo features have shown great potential in tissue *** hydrogel microstructures have been widely used to replace these native ECMs for physiologically r...
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Engineered extracellular matrices(ECMs)that replicate complex in-vivo features have shown great potential in tissue *** hydrogel microstructures have been widely used to replace these native ECMs for physiologically relevant ***,accurate reproduction of the 3D hierarchical and nonuniform mechanical stffness inside one integrated microstructure to mimic the complex mechanical properties of native ECMs presents a major ***,by using digital holographic microscopy(DHM)-based stffness imaging feedback,we propose a novel closed-loop control algorithm to achieve high-accuracy control of mechanical properties for hydrogel microstructures that recapitulate the physiological properties of native ECMs with high *** photoprinting,the photocuring area of the hydrogel is divided into microscale grid areas to locally control the photocuring *** the assistance of a motorized microfluidic channel,the curing thickness is controlled with layer-by-layer *** DHM-based stiffness imaging feedback allows accurate adjustment of the photocuring degree in every grid area to change the crosslinking network density of the hydrogel,thus enabling large-span and high-resolution modulation of mechanical ***,the gelatin methacrylate was used as a typical biomaterial to construct the highfidelity biomimetic *** Young's modulus could be flexibly modulated in the 10 kPa to 50 kPa ***,the modulus gradient was accurately controlled to within 2.9 *** engineering ECM with locally different mechanical properties,cell spreading along the stff areas was observed *** believe that this method can regenerate complex biomimetic ECMs that closely recapitulate in-vivo mechanical properties for further applications in tissue engineering and biomedical research.
In light of past epidemics, people have become more aware of the possibility of viruses on object surfaces and in the air. As a result, there is an increasing demand for robots capable of autonomously disinfecting sur...
Magnetic continuum robots (MCRs) show promising potential for applications in narrow lumens, such as vascular interventions. Accurate shape sensing of these robots is crucial for the success of interventional surgerie...
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The field of rehabilitation robotics has emerged as a prominent area of research in the medical community in recent years, offering innovative and promising solutions for patients with physical disabilities. The exist...
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Omnidirectional vehicles (ODVs) or mobile robots are widely used in various industries due to their ability to move and rotate in narrow spaces without the need for multiple adjustments of moving direction or stopping...
Omnidirectional vehicles (ODVs) or mobile robots are widely used in various industries due to their ability to move and rotate in narrow spaces without the need for multiple adjustments of moving direction or stopping. There are multiple types of ODVs, including those with standard wheels and those with special wheels such as Swedish wheels. Comprehensive characterization of the ODV's overall performance, which is very important when selecting specific configurations in the robot design process, is still missing in the literature. This paper qualitatively summarizes the comprehensive characteristics of three typical omnidirectional mobile robots in indoor scenarios through theoretical analysis and physical experiments. We compare the robot's performance through six representative evaluation metrics (maneuverability, efficiency, etc.) and express the results in a radar chart. The results of this study can assist designers in designing omnidirectional robots more effectively for specific application scenarios.
The performance of dynamic control is intimately tied to modeling accuracy. However, traditional estimation methods and friction models, such as the least squares method and the Coulomb plus viscous model, fail to ref...
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