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This paper aims to propose and verify an improved cascade active disturbance rejection control (ADRC) scheme based on output redefinition for hypersonic vehicles (HSVs) with nonminimum phase characteristic and model uncertainties.

To handle the nonminimum phase characteristic, a tuning factor stabilizing internal dynamics is introduced to redefine the system output states; its effective range is determined by analyzing Byrnes–Isidori normalized form of the redefined system. The extended state observers (ESOs) are used to estimate the uncertainties, which include matched and mismatched items in the system. The controller compensates observations in real time and appends integral terms to improve robustness against the estimation errors of ESOs.

Theoretical and simulation results show that the stability of internal dynamics is guaranteed by the tuning factor and the tracking errors of external commands are globally asymptotically stable.

The control scheme in this paper is expected to generate a reliable way for dealing with nonminimum phase characteristic and model uncertainties of HSVs.

In the framework of ADRC, a concise form of redefined outputs is proposed, in which the tuning factor performs a decisive role in stabilizing the internal dynamics of HSVs. By introducing an integral term into the cascade ADRC scheme, the compensation accuracy of matched and mismatched disturbances is improved.

One of the challenges encountered in the design of guided projectiles is their prohibitive cost. To diminish it, an appropriate avenue many researchers have explored is the use of the non-actuator method for guiding the projectile to the target. In this method, biologically inspired by the flying concept of the single-winged seed, for instance, that of maple and ash trees, the projectile undergoes a helical motion to scan the region and meet the target in the descent phase. Indeed, the projectile is a decelerator device based on the autorotation flight while it attempts to resemble the seed’s motion using two wings of different spans. There exists a wealth of studies on the stability of the decelerators (e.g. the mono-wing, samara and pararotor), but all of them have assumed the body (exclusive of the wing) to be symmetric and paid no particular attention to the scanning quality of the region. In practice, however, the non-actuator-guided projectiles are asymmetric owing to the presence of detection sensors. This paper aims to present an analytical solution for stability analysis of asymmetric decelerators and apprise the effects of design parameters to improve the scanning quality.

The approach of this study is to develop a theoretical model consisting of Euler equations and apply a set of non-dimensionalized equations to reduce the number of involved parameters. The obtained governing equations are readily applicable to other decelerator devices, such as the mono-wing, samara and pararotor.

The results show that the stability of the body can be preserved under certain conditions. Moreover, pertinent conclusions are outlined on the sensitivity of flight behavior to the variation of design parameters.

The analytical solution and sensitivity analysis presented here can efficiently reduce the design cost of the asymmetric decelerator.

The purpose of this paper is to improve autonomous flight performance of a fixed-wing unmanned aerial vehicle (UAV) via simultaneous morphing wingtip and control system design conducted with optimization, computational fluid dynamics (CFD) and machine learning approaches.

The main wing of the UAV is redesigned with morphing wingtips capable of dihedral angle alteration by means of folding. Aircraft dynamic model is derived as equations depending only on wingtip dihedral angle via Nonlinear Least Squares regression machine learning algorithm. Data for the regression analyses are obtained by numerical (i.e. CFD) and analytical approaches. Simultaneous perturbation stochastic approximation (SPSA) is incorporated into the design process to determine the optimal wingtip dihedral angle and proportional-integral-derivative (PID) coefficients of the control system that maximizes autonomous flight performance. The performance is defined in terms of trajectory tracking quality parameters of rise time, settling time and overshoot. Obtained optimal design parameters are applied in flight simulations to test both longitudinal and lateral reference trajectory tracking.

Longitudinal and lateral autonomous flight performances of the UAV are improved by redesigning the main wing with morphing wingtips and simultaneous estimation of PID coefficients and wingtip dihedral angle with SPSA optimization.

This paper originally discusses the simultaneous design of innovative morphing wingtip and UAV flight control system for autonomous flight performance improvement. The proposed simultaneous design idea is conducted with the SPSA optimization and a machine learning algorithm as a novel approach.

This paper aims to present a novel lightweight distribution grid operating robot system with focus on lightweight and multi-functionality, aiming for autonomous and live-line maintenance operations.

A ground-up redesign of the dual-arm robotic system with 12-DoF is applied for substantial weight reduction; a dual-mode operating control framework is proposed, with vision-guided autonomous operation embedded with real-time manual teleoperation controlling both manipulators simultaneously; a quick-swap tooling system is developed to conduct multi-functional operation tasks. A prototype robotic system is constructed and validated in a series of operational experiments in an emulated environment both indoors and outdoors.

The overall weight of the system is successfully brought down to under 150 kg, making it suitable for the majority of vehicle-mounted aerial work platforms, and it can be flexibly and quickly deployed in population dense areas with narrow streets. The system equips with two dexterous robotic manipulators and up to six interchangeable tools, and a vision system for AI-based autonomous operations. A quick-change tooling system ensures the robot to change tools on-the-go without human intervention.

The resulting dual-arm robotic live-line operation system robotic system could be compact and lightweight enough to be deployed on a wide range of available aerial working platforms with high mobility and efficiency. The robot could both conduct routine operation tasks fully autonomously without human direct operation and be manually operated when required. The quick-swap tooling system enables lightweight and durable interchangeability of multiple end-effector tools, enabling future expansion of operating capabilities across different tasks and operating scenarios.

Reducing aircraft fuel consumption has become a paramount research area, focusing on optimizing operational parameters like speed and altitude during the cruise phase. However, the existing methods for fuel reduction often rely on complex experimental calculations and data extraction from embedded systems, making practical implementation challenging. To address this, this study aims to devise a simple and accessible approach using available information.

In this paper, a novel analytic method to estimate and optimize fuel consumption for aircraft equipped with jet engines is proposed, with a particular emphasis on speed and altitude parameters. The dynamic variations in weight caused by fuel consumption during flight are also accounted for. The derived fuel consumption equation was rigorously validated by applying it to the Boeing 737–700 and comparing the results against the fuel consumption reference tables provided in the Boeing manual. Remarkably, the equation yielded closely aligned outcomes across various altitudes studied. In the second part of this paper, a pioneering approach is introduced by leveraging the particle swarm optimization algorithm (PSO). This novel application of PSO allows us to explore the equation’s potential in finding the optimal altitude and speed for an actual flight from Algiers to Brussels.

The results demonstrate that using the main findings of this study, including the innovative equation and the application of PSO, significantly simplifies and expedites the process of determining the ideal parameters, showcasing the practical applicability of the approach.

The suggested methodology stands out for its simplicity and practicality, particularly when compared to alternative approaches, owing to the ready availability of data for utilization. Nevertheless, its applicability is limited in scenarios where zero wind effects are a prevailing factor.

The research opens up new possibilities for fuel-efficient aviation, with a particular focus on the development of a unique fuel consumption equation and the pioneering use of the PSO algorithm for optimizing flight parameters. This study’s accessible approach can pave the way for more environmentally conscious and economical flight operations.

This chapter studies communication during a longitudinal crisis by exploring the Irish airline Ryanair’s use of Twitter (now X) in early 2022 when the coronavirus disease 2019 (COVID-19) pandemic had already been affecting the airline industry for almost 2 years. It studies the airline’s approach to interacting with its passengers online and their reaction to its posts, at times, rather provocative posts. A corpus linguistic methodology is used to study tweets posted by and addressed to Ryanair between January and March 2022, a period that saw unprecedented peaks in COVID-19 infection numbers and the simultaneous lifting of travel restrictions. The analysis is based on the Ryanair 2022 Corpus which includes 27,089 tweets and more than half a million words. The findings of this case study show that Ryanair reappropriates instructing and adapting information on crisis-related topics as promotion and takes a political stance in its tweets to encourage consumer engagement. While the corporate tweets are successful in generating reactions online, the airline’s followers do not always perceive them in a positive manner. This case study makes an important contribution to crisis communication research as it shows how established communicative strategies, such as instructing and adapting information, may be reappropriated during a longitudinal crisis. At the same time, it demonstrates how these communicative strategies may – as a consequence – no longer be aligned with the core values of a legitimate organisation that is expected to act responsibly and ethically.

This study investigates whether prolonged durations of work from home (WFH) leads to workplace ostracism (WO), and whether such relationship is moderated by perceived organizational support (POS). The context of this research is based on the post-COVID-19 pandemic period, when most organizations have either recalled their employees back to their physical workplaces, or in other cases employees are relegated to continued WFH or to a hybrid model that combines both in-office and remote work. The importance of this study is the spotlight it brings to employees who feel ostracized from their workplace due the continued practice of WFH.

A conceptual model is developed, by leveraging the conservation of resources (COR) theory. The hypotheses are tested by using cross-sectional survey data collected from 240 employees working in various organizations in the Sultanate of Oman from both public and private sectors. The data are analyzed using R Core Team software.

The findings of the study reveal that WFH does not have any direct impact on WO. However, when POS is applied as moderator, the results indicate that at low levels of POS, the relationship between WFH and WO becomes significant, but not at moderate to high levels of POS.

This study provides insights into how the phenomenon of WFH is likely to influence perceptions of employees in terms of feeling excluded from the organization by being asked to continue to work remotely, while many of their colleagues have returned to their prepandemic workplaces. The implications of the findings are relevant to the growing literature on employee experiences in the realm of emerging work models being introduced by organizations. Among the limitations of this study is the fact that there may be missing mediators that link WFH with WO, and the possibility that such a study if replicated in other cultural contexts may yield different results.

This study presents evidence to managers on leveraging the power of organizational support to ensure that negative emotions among employees such as WO are mitigated.

This appears to be among the first studies that attempts to provide insights into employee perceptions about WO in the postpandemic period, especially with regards to the emerging work arrangements that are primarily based on WFH that are being widely adopted by many organizations around the world. The results of this study provide useful information about how WFH and POS come together to influence emotions of individuals who have been longing to get back to their normal workplace once the social distancing guidelines of the pandemic were lifted.