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基于非凸低秩张量近似的图像超分辨率重建系统
No full text本发明涉及基于非凸低秩张量近似的图像超分辨率重建系统。在医学领域，磁共振图像(MRI)、计算机断层扫描图像等诸多医学成像方面总受到医疗系统固有硬件、医学图像采集时间的制约而缺乏高分辨率(HR)的医学图像。针对医学图像超分(SR)问题，本发明利用耦合加权三维全变分(3DTV)的块张量非凸近似方法来提高医学图像的分辨率。首先，对输入的低分辨率图像进行块匹配操作形成4D块，然后采用非凸张量惩罚函数挖掘其中蕴含的低秩结构特性、非局部自相似性。采用加权的三维全变分正则项来挖掘医学图像数据的局部平滑特性。该方法解决了医学图像的分辨率增强、抑制噪声及图像细节恢复等问题并实验验证了在不同采样率、噪声水平下该算法的优越性和泛化性
一种模块化直线运动驱动装置
No full text本发明涉及驱动装置，具体地说是一种模块化直线运动驱动装置，包括动力源、传动机构、导向机构、预紧机构、基座及多节支架，第一节支架的一端安装于基座上，从第二节支架开始的各节支架与相邻支架之间均相对伸缩地连接，第一节支架的另一端及其余各节支架上均安装有预紧机构；动力源安装于基座上，动力源的输出端通过传动机构与第二节支架连接；除第一节支架及最后一节支架之外的各节支架上均设有导向机构，动力源通过传动机构驱动第二节支架伸缩，从第二节支架开始的其余各节支架通过导向机构及预紧机构联动伸缩。本发明采用了高度集成化设计，实现了手术器械直线运动驱动装置的模块化，便于手术器械安装，可以实现多级导轨同步伸出
一种螺母自动上料机构
No full text本发明涉及自动化工业生产线的自动拧紧设备，特别涉及一种螺母自动上料机构。该机构包括螺母供顶机、螺母定位机构及螺母拾取机构，其中螺母供顶机通过螺母供顶机长直振将螺母自动有序的排列；螺母定位机构设置于螺母供顶机长直振的端部，用于对螺母供顶机长直振输送的螺母进行定位；螺母拾取机构设置于螺母供顶机上，且位于螺母定位机构的上方，螺母拾取机构用于拾取通过螺母定位机构定位的螺母。本发明实现了所有动作的自动化，将螺母出料、定位、拾取等动作进行了高度的集成，优化了结构，有效的解决了机构功能单一的问题，并降低了成本
一种无人机不规则油箱油量体积测量及显示系统
No full text本实用新型涉及一种无人机不规则油箱油量体积测量及显示系统包括：设于无人机上的油量体积测量及显示电路、无线模块、设于无人机油箱内的油量液位传感器；所述油量体积测量及显示电路包括处理器、串口电路、I2C通信接口电路、数码管驱动电路、油量刻度显示灯电路、电压转换电路，所述处理器通过串口电路连接油量液位传感器、无线模块，所述I2C通信接口电路经过数码管驱动电路连接油量刻度显示灯电路；电压转换电路分别连接处理器、串口电路、I2C通信接口电路、数码管驱动电路、油量刻度显示灯电路提供电源。本实用新型可以测量油量体积，为无人机作业任务规划人员提供可靠动力，避免无法精准测量油量剩余量而反复起降的重复性工作
Soft Exoskeleton With Fully Actuated Thumb Movements for Grasping Assistance
No full textIt has been clinically proven that exoskeletons are effective self-training rehabilitation or daily living assistance devices for patients with hand dysfunctions. However, exoskeleton-assisted hand exercises with high degrees-of-freedom are considered as challenging tasks because the digit space, especially the thumb, cannot accommodate enough actuators. In this article, we report a tendon-driven soft hand exoskeleton with a hybrid configuration for thumb actuation. The soft hand exoskeleton system uses the least number of actuators to realize full degrees-of-freedom actuation for all digits. It is tested on a stroke patient with hemiplegia and a healthy subject. The experimental results show that the hand exoskeleton could assist the stroke patient to accomplish various training tasks, such as thumb encircling, grasping, pinching, releasing, and writing. It was found that digit trajectories and joint angle changes of the stroke patient were close to those of the healthy subject. Especially, the range of motion of the stroke patient shows significant improvement with the hand exoskeleton assistance compared to that without the hand exoskeleton assistance. The research in this article paves the way to develop fully actuated soft hand exoskeleton that can be eventually integrated with an electroencephalogram or electromyography for self-training rehabilitation or daily living assistance
Vibration and Reliability Analysis of Non-Uniform Composite Beam under Random Load
No full textNon-uniform structures and composite materials have advantages in engineering applications, such as light weight design, multi-functionality, and better buckling/flutter load capacity. For composite structures under dynamic loading conditions, reliability is a key problem to be analyzed during practical operations. However, there is little research work on non-uniform composite structural reliability analysis under random load. The forced vibration response of non-uniform composite beam under random load is firstly solved by the Adomian Decomposition Method (ADM) and iterative process for reliability analysis. Different variation laws of the cross-section rigidity and mass distribution along the length of the non-uniform composite beam structures are analyzed. Various angular frequency and amplitude of random base motion acceleration following Gaussian distribution are considered. Influences of different random excitations and structural design on vibration responses and reliability are studied. The larger mean and variance of excitation frequency leads to the smaller amplitude and strain of the beam, while greater mean and variance of the base motion excitation amplitude will induce the higher maximum amplitude and strain values and lower reliability. The influences of structural design on reliability are studied. The reliability increases with the increment of taper ratios of the host beam and composite layer. The iteration mathematical model and numerical solutions proposed in this paper can be used to solve and analyze vibration responses and reliability of general non-uniform composite beam structures under arbitrary excitation during a certain period of time
Bubble-based microrobots enable digital assembly of heterogeneous microtissue modules
No full textThe specific spatial distribution of tissue generates a heterogeneous micromechanical environment that provides ideal conditions for diverse functions such as regeneration and angiogenesis. However, to manufacture microscale multicellular heterogeneous tissue modules in vitro and then assemble them into specific functional units is still a challenging task. In this study, a novel method for the digital assembly of heterogeneous microtissue modules is proposed. This technique utilizes the flexibility of digital micromirror device-based optical projection lithography and the manipulability of bubble-based microrobots in a liquid environment. The results indicate that multicellular microstructures can be fabricated by increasing the inlets of the microfluidic chip. Upon altering the exposure time, the Young's modulus of the entire module and different regions of each module can be fine-tuned to mimic normal tissue. The surface morphology, mechanical properties, and internal structure of the constructed bionic peritoneum were similar to those of the real peritoneum. Overall, this work demonstrates the potential of this system to produce and control the posture of modules and simulate peritoneal metastasis using reconfigurable manipulation.</p
Adaptive Learning Attention Network for Underwater Image Enhancement
No full textUnderwater images suffer from color casts and low illumination due to the scattering and absorption of light as it propagates in water. These problems can interfere with underwater vision tasks, such as recognition and detection. We propose an adaptive learning attention network for underwater image enhancement based on supervised learning, named LANet, to solve these degradation issues. First, a multiscale fusion module is proposed to combine different spatial information. Second, we design a novel parallel attention module (PAM) to focus on the illuminated features and more significant color information coupled with the pixel and channel attention. Then, an adaptive learning module (ALM) can retain the shallow information and adaptively learn important feature information. Further, we utilize a multinomial loss function that is formed by mean absolute error and perceptual loss. Finally, we introduce an asynchronous training mode to promote the network's performance of multinomial loss function. Qualitative analysis and quantitative evaluations show the excellent performance of our method on different underwater datasets. The code is available at: https:// github.com/LiuShiBen/LANet
Multi-scale simulation of microstructure evolution during direct laser deposition of Inconel718
No full textAs a free forming additive manufacturing technology for high performance metal parts, laser deposition manufacturing has a broad application prospect in aerospace and other fields. The solidification behavior and microstructure of molten pool determine the mechanical properties of the deposited parts. A multi-scale Cellular Automaton (CA)- Finite Element (FE) model is developed to simulate the microstructure evolution with different process parameters during the Direct Laser Deposition (DLD) process. Temperature data and solidification parameters under different process parameters are obtained by finite element method, which establish connections between macroscopic temperature field and microstructure simulation. In addition, the effects of different process parameters on dendrite morphology, element segregation and grain structure are investigated. The primary dendrite arm spacing (PDAS), Nb element precipitation and grain size all increase with the increase of laser power, which are caused by the decrease of cooling rate. Moreover, the trend of the simulated results of microstructure under various process parameters are consistent with the experimental results.</p
A Safe and Compliant Noncontact Interactive Approach for Wheeled Walking Aid Robot
No full textAiming at promptly and accurately detecting falls and drag-to gaits induced by asynchronous human-robot movement speed during assisted walking, a noncontact interactive approach with generality, compliance and safety is proposed in this paper, and is applied to a wheeled walking aid robot. Firstly, the structure and the functions of the wheeled walking aid robot, including gait rehabilitation robot (GRR) and walking aid robot (WAR) are illustrated, and the characteristic futures of falls and the drag-to gait are shown by experiments. To obtain gait information, a multichannel proximity sensor array is developed, and a two-dimensional gait information detection system is established by combining four proximity sensors groups which are installed in the robot chassis. Additionally, a node-iterative fuzzy Petri net algorithm for abnormal gait recognition is proposed by generating the network trigger mechanism using the fuzzy membership function. It integrates the walking intention direction vector by taking gait deviation, frequency, and torso angle as input parameters of the system. Finally, to improve the compliance of the robot during human-robot interaction, a PID_SC controller is designed by integrating the gait speed compensation, which enables the WAR to track human gait closely. Abnormal gait recognition and assisted walking experiments are carried out respectively. Experimental results show that the proposed algorithm can accurately identify abnormal gaits of different groups of users with different walking habits, and the recognition rate of abnormal gait reaches 91.2%. Results also show that the developed method can guarantee safety in human robot interaction because of user gate follow-up accuracy and compliant movements. The noncontact interactive approach can be applied to robots with similar structure for usage in walking assistance and gait rehabilitation.</p