Configuration system design and longitudinal flight simulation verification of variable stability helicopter

For in-flight simulation of variable stability helicopter, how to have the ability to change a wide range of response characteristics and ensure flight safety is an important design problem. This paper proposes configuration design technology of the variable stability helicopter, which purpose is to safely change steady-state and dynamic response characteristics of the variable stability helicopter, and make the pilot feel good or poor helicopter response characteristics. The configuration control system of the variable stability helicopter is designed theoretically, and the configuration switch logic is studied from the perspective of flight safety. The numerical simulation test of the longitudinal configuration control law was carried out, and the configuration control law and configuration switch logic were added to the ground closed-loop test to verify. The results show that the expected response characteristics of the helicopter are obtained by applying the configuration system design technology

Evaluating imaging repeatability of fully self-service fundus photography within a community-based eye disease screening setting

Abstract Purpose This study aimed to investigate the imaging repeatability of self-service fundus photography compared to traditional fundus photography performed by experienced operators. Design Prospective cross-sectional study. Methods In a community-based eye diseases screening site, we recruited 65 eyes (65 participants) from the resident population of Shanghai, China. All participants were devoid of cataract or any other conditions that could potentially compromise the quality of fundus imaging. Participants were categorized into fully self-service fundus photography or traditional fundus photography group. Image quantitative analysis software was used to extract clinically relevant indicators from the fundus images. Finally, a statistical analysis was performed to depict the imaging repeatability of fully self-service fundus photography. Results There was no statistical difference in the absolute differences, or the extents of variation of the indicators between the two groups. The extents of variation of all the measurement indicators, with the exception of the optic cup area, were below 10% in both groups. The Bland–Altman plots and multivariate analysis results were consistent with results mentioned above. Conclusions The image repeatability of fully self-service fundus photography is comparable to that of traditional fundus photography performed by professionals, demonstrating promise in large-scale eye disease screening programs