To solve the problem of space debris, a film capture pocket system is designed in this paper. The film capture pocket is more flexible and reliable, compared with the space rope net. The film capture pocket system contains many flexible structures that are prone to large deformation and vibration during movement. The deformation causes large disturbances to the service spacecraft. It is necessary to establish an accurate rigid-flexible coupling dynamic model for quantitative analysis of disturbances. First, a film dynamic model is developed using high-order absolute nodal coordinate formulation. Second, an attitude tracking control law is designed by using the fast nonsingular terminal sliding mode controller and fixed time dilation observer (FxESO). Finally, combining dynamics and control principles, a virtual prototype of spacecraft with film capture pocket system is established. The simulation results show that higher-order absolute nodal coordinate formulation elements have better convergence, compared to ABAQUS finite element analysis. Meanwhile, the dynamic model simulates the deformation and vibration states of large flexible structures, during the spacecraft maneuver. The FxESO can estimate and compensate the complex disturbance. The error under fast nonsingular terminal sliding mode + FxESO control law converge more rapidly than the nonsingular terminal sliding mode + expansion observer control law. The final spacecraft attitude tracking error is about 10 ⁻⁴ , indicating the effectiveness of the controller.

The design optimization of wind turbines and their subsystems will make them competitive as an ideal alternative for energy. This paper proposed a design procedure for one of these subsystems, which is the Wind Turbine Drive-Train (WTDT). The design of the WTDT is based on the load assumptions and considered as the most significant parameter for increasing the efficiency of energy generation. In industry, these loads are supplemented by expert assumptions and manipulated to design the transmission elements. In contrary, in this work, the multibody system approach is used to estimate the static as well as dynamic loads based on the Lagrange multipliers. Lagrange multipliers are numerical parameters associated with the holonomic and nonholonomic constraints assigned in the drive-train model. The proposed scheme includes computational manipulations of kinematic constraints, mapping the generalized forces into Cartesian respective, and enactment of velocity-based constrains. Based on the dynamic model and the obtained forces, the design process of a planetary stage of WTDT is implemented with trade-off’s optimization in terms of gearing parameters. A wind turbine of 1.4 megawatts is introduced as an evaluation study of the proposed procedure, in which the main advantage is the systematic nature of designing complex systems in motion.