Aerial work platform is a kind of engineering vehicle which is used for hoisting personnel to the appointed place for maintenance or installation. Based on the dynamics model considering the flexible deformation existing in the arm system of folding-boom aerial platform vehicle, this study presents a NN-based backstepping controller used for trajectory tracking control of work platform. The proposed controller can reduce tracking error of work platform and suppress the vibration simultaneously by using the RBF neural network system to compensate (...) model uncertainties and disturbances. Furthermore, we prove that the whole system is stable and convergent by Lyapunov stability theorem. In addition, we give the simulation results which show that the good control performance of the designed controller for trajectory tracking and vibration inhabiting of work platform in the case of model uncertainties. (shrink)

Educational aspirations under an ideal state and educational expectations based on reality have an important impact on children’s academic development, but distinct differences between them exist. On the basis of distinguishing the differences between the two, using the national data of Tsinghua University’s China Urbanization and Child Development Survey, this article endeavors to explore the inequality of educational aspirations and expectations from the perspective of class and urban-rural areas, and lay out the influencing factors of educational aspirations, expectations, and the (...) difference between them. It is found that Chinese parents generally have high aspirations for their children’s education. There is no distinct class difference in “high hopes for children’s bright future.” However, in the sense of educational expectations, there are distinct class differences, which are deeply rooted in socioeconomic status and closely related to education level, family type, family structure, and family economic status, as well as children’s academic performance. (shrink)