Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： A rigid-flexible hybrid variable trailing edge wing is proposed to realize the contimuous chordwise camber change of the wing under drive control. Among them，flexible pneumatic muscle is used asthe driving device for the flexible section structure of the wing. In the study on the controlling method,first , the pneumatic muscle drive force model is derived. Then, the pseudo-rigid body modeling method isused to approximate the flexible structure as a single-joint robotic arm structure and establish its dynamicsmodel. In the next step，the Pl control model of the sliding mode variable structure based on the nominalmodel is established ， and the proportional coefficients，integral coefficients and sliding mode surface pa-rameters are rectified. On this basis , the test platform of variable camber control of the flexible section ofthe wing rib and the integrated deflection control platform of the typical wing box section are built.Through the tests,the ability of the flexible section structure to achieve the target camber in the elastic de-formation range is verified. The error between the actual deformation curve of wing rib and the target de-formation curve is only 8% . The dynamic performance of the control method and parameters are tested.'The actuation response time is 5. 5 s,the overshoot is 0，and the steady-state error is 6% . The test results verify the reasonableness and effectiveness of the control system. Finally, a comprehensive control test ofthe target angle is conducted for the wing box to test the variable structure performance of the overall system.
Subjects: Psychology >> Developmental Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： Full-information item bifactor analysis is an important statistical method in psychological and educational measurement, which can be seen as a rediscovery of the classical bifactor model and has seen wide applications in the past two decades. The item response model of full-information item bifactor analysis is described upon the introduction of the conception and characterization of full-information item bifactor analysis. Further, we introduced the dimension reduction method used in parameter estimation. Then, examples are provided for applications of the full-information item bifactor model in test measurement structure exploration or confirmation, score interpretation, and computerized adaptive testing. The measurement structure of full-information item bifactor analysis is accordance with most tests in the areas of psychology, education, and medical science. With the advantage in dimension reduction, it is believed that the full-information item bifactor analysis could be valuable and useful in various situations. At last, some future research directions and suggestions are put forward including parameter estimation, test linking, differential item functioning, model fit testing, and application of bifactor item response theory to computerized adaptive testing.
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