Modeling and switching adaptive control for nonlinear morphing aircraft considering actuator dynamics

This paper investigates the problems of modeling and control of the morphing aircraft. Henceforth, a nonlinear dynamic model of a wing-sweep morphing aircraft is first established in this work. This model is suitable for larger envelopes by elaborating the variation of aerodynamic coefficients, air density, mass distribution at different altitudes, Mach numbers, and sweep angles. Considering the alterations in the dynamic characteristics of the morphing aircraft owing to the various flight conditions, we design the switching adaptive backstepping controllers for the altitude subsystem and velocity subsystem. The actuator dynamics have been explicitly included in the process of the controller design to alleviate the chattering problem caused by the switching. Furthermore, the closed-loop stability is rigorously proved via the Lyapunov stability theory and the technique of compact set. Comparative results from the simulations finally validate the effectiveness of the proposed scheme.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Bart De Schutte

Augmented Lagrangian relaxation-based coordinated approach for global synchromodal transport planning with multiple operators

Global synchromodal transportation is a promising strategy for providing efficient, reliable, flexible, and sustainable container shipping services across continents. It involves integrating multiple modes and routes owned by various operators to create a comprehensive transport plan. However, these operators often have their own local networks and are hesitant to cede control to a centralized platform. Instead, they prefer to share limited information in a coordinated manner to achieve a common goal without sacrificing their own benefits. This paper proposes a coordinated mechanism for global synchromodal transport planning, in which a global operator proposes incentives to local operators to select the most efficient modes and routes for shipping containers from one continent to another. An augmented Lagrangian relaxation approach is developed for the global operator to generate incentives, and a heuristic algorithm is designed to address the computational complexity of the optimization problems faced by local operators. We incorporate the proposed approaches with a rolling horizon framework to handle dynamic shipment requests received from spot markets and with a buffer strategy to address travel time uncertainties. The coordinated mechanism is tested on a real network between Asia and Europe, and results show that it can significantly increase total profits, reduce request rejections, and reduce infeasible transshipments compared to decentralized global transportation plans currently in use, particularly under scenarios with higher degrees of dynamism and uncertainty.Transport Engineering and LogisticsTransport and Plannin

Feasibility study for the introduction of synchromodal freight transportation concept

The current weaknesses of the conventional intermodal freight transportation system have led to the development of the synchromodal freight transportation concept introduced and piloted in the Netherlands. The innovative concept has the advantage of adding flexibility, cost reduction, and sustainability among other things, into the freight transportation system. The synchromodal system has not been started in any developing country yet due to its newness. In this study, we used multiple methodologies to conduct a feasibility study for the possibilities of introducing the concept in a developing country, Ghana. An intensive literature review was performed using the Grounded Theory and the Critical Success Factors (CSFs) method to identify the key factors for the introduction of the synchromodal concept. Questionnaires were administered to the primary stakeholders in the maritime-hinterland transportation sector to solicit their views about the factors necessary for the implementation. We next carried out SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis to catalogue the strengths and weakness of the country in introducing the concept. The multiple regression analysis method was used to analyse the experience of stakeholders in the freight transportation business and their knowledge about the synchromodal freight transportation system. The results of the study show that it is possible to introduce the concept in the country. However, there is the need to improve the current transportation and ports infrastructure of the country considerably for successful synchromodal system adaptation. There is also the need for stakeholders education on the concept.Transport Engineering and Logistic

In Silico Insights into the Symbiotic Nitrogen Fixation in Sinorhizobium meliloti via Metabolic Reconstruction

Background: Sinorhizobium meliloti is a soil bacterium, known for its capability to establish symbiotic nitrogen fixation (SNF) with leguminous plants such as alfalfa. S. meliloti 1021 is the most extensively studied strain to understand the mechanism of SNF and further to study the legume-microbe interaction. In order to provide insight into the metabolic characteristics underlying the SNF mechanism of S. meliloti 1021, there is an increasing demand to reconstruct a metabolic network for the stage of SNF in S. meliloti 1021