This paper proposes two different path following control schemes for a stratospheric airship with actuator saturation. Each of the control schemes consists of a guidance loop and an attitude control loop. In both schemes, guidance laws are designed according to the line-of-sight guidance-based path following principle. In the first control scheme, a robust H∞ controller without constraints is designed based on the planar model of a stratospheric airship to stabilize path-following errors. The input constraints are then addressed by using a regional [Formula: see text]-based model recovery anti-windup compensator, which prevents the unconstrained controller from misbehaving in the constrained closed loop with anti-windup augmentation and ensures the systematic stability. In the second control scheme, model predictive control is applied to guarantee the path-following of the closed-loop system and explicitly address the magnitude and rate of rudders of the stratospheric airship. Theoretical results are illustrated by numerical simulations where both closed-loop systems are capable of following their desired paths and the constraints on control inputs are satisfied.

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Local chemical order (LCO) can exert pronounced effects on both structural and functional properties, tailoring LCO domains at (sub-)nanoscale could offer an alternative material-design concept for yet unexplored performance. However, the origin of LCO remains an open question, making accurate manipulation of LCO extremely challenging. Here we selected the Fe-Ga magnetostrictive materials and demonstrated that LCO tetragonal structures play a significant role in optimizing the magnetostrictive properties. The “full-lifecycle”, including formation, evolution and dissolution of LCO, is concretely studied from the atomic-scale up by combined experimental and theoretical studies. The dynamic precipitation and dissolution processes of LCO L60 domains during isothermal aging are directly observed based on in-situ high-resolution transmission electron microscopy images, and the corresponding mechanisms are revealed by first-principles calculation. Based on the results, we evidence that LCO domain is a frozen-intermediate-states of a kinetically-slow solid-state phase transformation leading to the formation of the long-range-ordered equilibrium phase with a face-center-cubic structure. We confirm the reversibility of LCO during cycling treatments. Our findings shed light on the origin of LCO in a range of material systems, and we discuss directions for developing materials with superior performance by manipulating LCO domains.

This paper proposes a control scheme of disturbance rejection based path following for a stratospheric airship with actuator saturation. Firstly, the path following control algorithm is designed according to line-of-sight guidance. Secondly, without concerning the input constrains, the robust H∞ controller is designed based on a planar model of the stratospheric airship. Then, the input constrains are taken into account and model recovery anti-windup (MRAW) compensator is designed and used in stratospheric airship. The proposed method can minimize the influence of external disturbances, keep the unconstrained controller from misbehaving in the constrained closed loop with anti-windup augmentation and ensure the systematic stability. Finally, simulation results show the effectiveness of the proposed method.