Reliability Evaluation for Cable-Spring Folding Wing Considering Synchronization of Deployable Mechanism

The cable-spring folding wing is a novel type of rigid-flexible coupling structure for missiles, which is composed of several sets of deployable mechanisms, with each composed of a wheel-rope transmission system and a parallel spring driving mechanism. The movement of the cable is initiated by the driving force produced by parallel springs, which directly changes the magnitude and the distribution of the driving force. Therefore, the cable-spring folding wing system has the typical characteristics of strong nonlinearity and motion coupling. In addition, each deployable mechanism shares an identical structure, but the distribution of motion parameters is discrepant due to external loads. Asynchronous movement of the cable-spring folding wing will occur and become a significant issue, which is detrimental to the working performance and could even lead to failure. Focusing on these problems, the multi-body dynamics theoretical model and simulation model of deployable mechanism are established, the kinematic and dynamic characteristics of critical components are studied, and the key factors affecting the deployment performance are investigated. A new reliability method with an angular precision control for deployable mechanism is proposed based on the theoretical model. The effectiveness of the proposed model and method is verified by comparing it with the Monte Carlo method. On this basis, the reliability evaluation for cable-spring folding wing, comprehensively considering deployment performance and synchronization, is carried out.

An AI-assisted Online Tool for Cognitive Impairment Detection Using Images from the Clock Drawing Test

BackgroundWidespread early dementia detection could drastically increase clinical trial candidates and enable early interventions. Since the Clock Drawing Test (CDT) can be potentially used for diagnosing dementia related diseases, it can be leveraged to devise a computer-aided screening tool.ObjectiveThis work aims to develop an online screening tool by leveraging Artificial Intelligence and the CDT.MethodsImages of an analog clock drawn by 3, 263 cognitively intact and 160 impaired subjects were used. First, we processed the images from the CDT by a deep learning algorithm to obtain dementia scores. Then, individuals were classified as belonging to either category by combining CDT image scores with the participant’s age.ResultsWe have evaluated the performance of the developed models by applying 5-fold cross validation on 20% of the dataset. The deep learning model generates dementia scores for the CDT images with an Area Under the ROC Curve (AUC) of 81.3% ± 4.3%. A composite logistic regression model using age and the generated dementia scores, yielded an average AUC and average weighted F1 score of 92% ± 0.8% and 94.4% ± 0.7%, respectively.DiscussionCDT images were subjected to distortion consistent with an image drawn on paper and photographed by a cell phone. The model offers a cost-effective and easily deployable mechanism for detecting cognitive impairment online, without the need to visit a clinic.

Design and analysis of a novel deployable hexagonal prism module for parabolic cylinder antenna

This paper presents a novel deployable hexagonal prism module for parabolic cylinder antennas that exhibit characteristics of geometric scalability. The hexagonal prism module consists of six basic rib mechanisms distributed along the axis and parabolic directions of the parabolic cylinder. The basic rib mechanism along the axis direction is designed, and the position of each member in the deployed state is calculated according to the geometric relationships at the folded state. The basic rib mechanism along the parabolic direction is designed to ensure that the mechanism can be fully folded. The degree of freedom of basic loop mechanisms consisting of four basic rib mechanisms due to the splice of multiple modules is analyzed. The degree of freedom of the proposed hexagonal prism module is verified through simulations and experiments of a deployable mechanism composed of three hexagonal prism modules. The simulation and experiment results show that the proposed hexagonal prism module can offer synchronized and coordinated movement during the deployment process.