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This scheme makes the best use of structure of the cargo ship by integrating with air-breathing helicon plasma electrical propulsion. The normal operation of a manned space station requires regular replenishment of oxygen, fuel, food and instruments. Research on resupply spacecraft to supply oxygen and fuel to the space station will help reduce the replenishment needs of the station. A resupply spacecraft with air-breathing electrical propulsion as core technology will meet the replenishment needs of the space station during on-orbit operation at a low cost and bring high loading capacity and substantial economic benefits. The replenishment ship based on this scheme can collect 1000 kg working gas a year on 180 km orbit and reduce the cost of building and launching cargo ships. This paper carried out studies on mission process, resource consumption, orbit design and thrust Analysis. The ionization mode of air-breathing electrical propulsion is helicon discharge and the average power for orbit maintaining and air collecting is about 775 W.

In this paper, an integrated control problem is investigated for the Air-breathing hypersonic vehicle (AHSV). The coupling dynamic model of AHSV is first provided by the Quasi One-dimensional flow theory, and the mechanical properties is analyzed. Furthermore, the integrated guidance and control laws are presented based on the proposed model and analysis result. Finally, the comparison simulation results show that the proposed integrated control approach has the better control performance against the decoupled control approach.

Previous reports suggested the existence of direct somatic motor control over heart rate (fH) responses during diving in some marine mammals, as the result of a cognitive and/or learning process rather than being a reflexive response. This would be beneficial for O2storage management, but would also allow ventilation-perfusion matching for selective gas exchange, where O2and CO2can be exchanged with minimal exchange of N2. Such a mechanism explains how air breathing marine vertebrates avoid diving related gas bubble formation during repeated dives, and how stress could interrupt this mechanism and cause excessive N2exchange. To investigate the conditioned response, we measured thefH-response before and during static breath-holds in three bottlenose dolphins (Tursiops truncatus) when shown a visual symbol to perform either a long (LONG) or short (SHORT) breath-hold, or during a spontaneous breath-hold without a symbol (NS). The averagefH(ifHstart), and the rate of change infH(difH/dt) during the first 20 s of the breath-hold differed between breath-hold types. In addition, the minimum instantaneousfH(ifHmin), and the average instantaneousfHduring the last 10 s (ifHend) also differed between breath-hold types. The difH/dt was greater, and the ifHstart, ifHmin, and ifHendwere lower during a LONG as compared with either a SHORT, or an NS breath-hold (P< 0.05). Even though the NS breath-hold dives were longer in duration as compared with SHORT breath-hold dives, the difH/dt was greater and the ifHstart, ifHmin, and ifHendwere lower during the latter (P< 0.05). In addition, when the dolphin determined the breath-hold duration (NS), thefHwas more variable within and between individuals and trials, suggesting a conditioned capacity to adjust thefH-response. These results suggest that dolphins have the capacity to selectively alter thefH-response during diving and provide evidence for significant cardiovascular plasticity in dolphins.

Lithium-oxygen (Li-O2) batteries have been intensively investigated in recent decades for their utilization in electric vehicles. The intrinsic challenges arising from O2 (electro)chemistry have been mitigated by developing various types of catalysts, porous electrode materials, and stable electrolyte solutions. At the next stage, we face the need to reform batteries by substituting pure O2 gas with air from Earth's atmosphere. Thus, the key emerging challenges of Li-air batteries, which are related to the selective filtration of O2 gas from air and the suppression of undesired reactions with other constituents in air, such as N2, water vapor (H2O), and carbon dioxide (CO2), should be properly addressed. In this review, we discuss all key aspects for developing Li-air batteries that are optimized for operating in ambient air and highlight the crucial considerations and perspectives for future air-breathing batteries.

In some fishes, the ability to breathe air has evolved to overcome constraints in hypoxic environments but comes at a cost of increased predation. To reduce this risk, some species perform group air breathing. Temperature may also affect the frequency of air breathing in fishes, but this topic has received relatively little research attention. This study examined how acclimation temperature and acute exposure to hypoxia affected the air-breathing behaviour of a social catfish, the bronze corydoras Corydoras aeneus, and aimed to determine whether individual oxygen demand influenced the behaviour of entire groups. Groups of seven fish were observed in an arena to measure air-breathing frequency of individuals and consequent group air-breathing behaviour, under three oxygen concentrations (100%, 60% and 20% air saturation) and two acclimation temperatures (25 and 30°C). Intermittent flow respirometry was used to estimate oxygen demand of individuals. Increasingly severe hypoxia increased air breathing at the individual and group levels. Although there were minimal differences in air-breathing frequency among individuals in response to an increase in temperature, the effect of temperature that did exist manifested as an increase in group air-breathing frequency at 30°C. Groups that were more socially cohesive during routine activity took more breaths but, in most cases, air breathing among individuals was not temporally clustered. There was no association between an individual's oxygen demand and its air-breathing frequency in a group. For C. aeneus, although air-breathing frequency is influenced by hypoxia, behavioural variation among groups could explain the small overall effect of temperature on group air-breathing frequency., Summary: Temperature effects on air breathing in an air-breathing fish are not consistent at the individual and group levels, suggesting that social dynamics can obscure links between physiology and behaviour.

The aquatic habitat of marine “air-breathing” vertebrates provides a significant thermoregulatory challenge due to the high thermal conductivity of water. In addition to temperature changes across their range, air-breathing vertebrates experience temperature changes on the timescale of seconds to minutes as they perform dives to access two critical resources: air at the surface and food at depth. In response to these challenges, air-breathing vertebrates have developed morphological and physiological adaptations that align with their life histories and phylogenies and contribute to homeostasis. However, the physiological and behavioral mechanisms used to maintain thermal balance while diving is still poorly understood. The cardiovascular system is integral to the physiological responses associated with the dive response, exercise, digestion, and thermoregulation. The adjustments required to meet one physiological demand may not be compatible with another and can result in a potential conflict between the various physiological demands imposed on air-breathing divers. We reviewed the literature on thermoregulation while diving in an effort to synthesize our current understanding of the thermoregulatory strategies of diving air-breathing marine vertebrates. Studies have demonstrated that thermoregulatory strategies can involve the temporal separation of two conflicting responses, a compromise in the performance of one response over another, or coordination of synergistic responses. We hope that a review and synthesis of both laboratory and field studies will stimulate future research efforts at the intersection of thermoregulation and diving physiology. Expanding the use of physiological biologgers, particularly to understudied species, will enhance our understanding of how these animals coordinate various physiological demands to maintain homeostasis in a thermally challenging environment.

It is expected that aquaculture alone will provide around two third of global fish consumption by 2030, as catches from wild capture fisheries has been either decreasing or stagnant. Majority of the air breathing fish species have very high consumer preference as food fish for their unique taste, nutritional and therapeutic value. Although these species are often considered as weed and unwanted fish in aquaculture, yet they play an important role in supplementing the nutritional requirement of resource poor fishers and farmers and providing livelihood through ornamental fish trade for entrepreneurs. However, not much scientific information is available on the nutritional requirement and food habit of the air breathing fish species. A change or transformation of feeding habit of several air breathing fish species with the advances of their life stages have been reported.

International audience; Myriapods were, together with arachnids, the earliest animals to occupy terrestrial ecosystems, by at least the Silurian. The origin of myriapods and their land colonization have long remained puzzling until euthycarcinoids, an extinct group of aquatic arthropods considered amphibious, were shown to be stem-group myriapods, extending the lineage to the Cambrian and evidencing a marine-to-terrestrial transition. Although possible respiratory structures comparable to the air-breathing tracheal system of myriapods are visible in several euthycarcinoids, little is known about the mechanism by which they respired. Here, we describe a new euthycarcinoid from Upper Devonian alluvio-lagoonal deposits of Belgium. Synchrotron-based elemental X-ray analyses were used to extract all available information from the only known specimen. Sulfur X-ray fluorescence (XRF) mapping and spectroscopy unveil sulfate evaporation stains, spread over the entire slab, suggestive of a very shallow-water to the terrestrial environment prior to burial consistent with an amphibious lifestyle. Trace metal XRF mapping reveals a pair of ventral spherical cavities or chambers on the second post-abdominal segment that do not compare to any known feature in aquatic arthropods, but might well play a part in air-breathing. Our data provide additional support for amphibious lifestyle in euthycarcinoids and show that different respiratory strategies were used during the marine-to-terrestrial transition in the myriapod lineage.

A simple and novel membraneless paper-based microfluidic fuel cell was presented in this study. The occurrence of laminar flow was employed to ensure no mixing of the fuel and oxidant fluids along ...

An integrated approach that considers the performance limitations of tracking control systems for air-breathing hypersonic vehicles is proposed. First, a set of ascent trajectories is obtained as candidates for tracking control through a trajectory design method that considers the available acceleration. Second, the basic theory of performance limitations, which is adopted to calculate the limits on control performance through the trajectory, is integrated. The open-loop dynamics of air-breathing hypersonic vehicles is responsible for these limits on the control system. Comprehensive specifications on stability, tracking accuracy, and robustness are derived, and the flight envelope with constraints and control specifications is identified. Simulation results suggest that trajectory design should consider restrictions on control performance to obtain reliable solutions. Keywords: Bandwidth constraints, Hypersonic vehicles, Performance limitations, Robust performance, Trajectory tracking control

International audience; Air-breathing and amphibious fishes are essential study organisms to shed insight into the required physiological shifts that supported the full transition from aquatic water-breathing fishes to terrestrial air-breathing tetrapods. While the origin of air-breathing in the evolutionary history of the tetrapods has received considerable focus, much less is known about the evolutionary physiology of air-breathing among fishes. This review summarises recent advances within the field with specific emphasis on the cardiorespiratory regulation associated with air-breathing and terrestrial excursions, and how respiratory physiology of these living transitional forms are affected by development and personality. Finally, we provide a detailed and re-evaluated model of the evolution of air-breathing among fishes that serves as a framework for addressing new questions on the cardiorespiratory changes associated with it. This review highlights the importance of combining detailed studies on piscine air-breathing model species with comparative multi-species studies, to add an additional dimension to our understanding of the evolutionary physiology of air-breathing in vertebrates.

Six-degree-of-freedom measurements have been performed with an aerodynamic model of a small-scale hypersonic air-breathing vehicle. The model was tested in two test campaigns in two different wind ...

This paper focuses on the fault-tolerant control problem of air-breathing hypersonic vehicles (AHVs) by using the adaptive method. A tractable control-oriented model is first derived for AHVs with ...

The evolution of air-breathing and transition from water to land were pivotal events that greatly determined the ecological diversification, the advances and the successes of animal life. During their relocation onto land, the so-called bimodal breathers were literally caught at the water-air interface. Among such animals are the diverse air-breathing bony fish. Such taxa, however, strictly do not constitute the so-called 'bridging animals', i.e., the inaugural animals that crossed from water to land, nor are they their direct progenitors. The pioneer transitional animals were the Devonian rhipidistian amphibians that possessed a primitive lung which acquired O2 directly from air and discharged CO2 back into the same. By having particular morphological and physiological adaptations for terrestrialness, the modern amphibious- and aquatic air-breathers are heuristic analogues of how and why animals relocated from water to land. It has generally been espoused that lack or dearth of O2 in water, especially in the warm tropical one, was an elemental driver for adoption of air-breathing. There is, however, no direct causal relationship between the evolution of air-breathing and the shift onto land: the move onto land was a direct solution to the existing inimical respiratory conditions in water. This is evinced in the facts that: a) even after attaining capacity of air-breathing, an important preadaptation for life on land, some animals continued living in water while periodically accessing air, b) in the fish species that live in the well-oxygenated waters, e.g., torrential rivers, only few air-breathe and c) air-breathing has still evolved in freshwaters and seawaters, where levels of dissolved O2 are sufficiently high. Here, the structure and function of the respiratory organs of the air-breathing fish are succinctly outlined. Two African catfishes, Clarias mossambicus and C. gariepinus are highlighted.

During water-land transition, ancient fishes acquired the ability to breathe air, but air-breathing engendered problems in nitrogenous waste excretion. Nitrogen is a fundamental component of amino acids, proteins, and nucleic acids, and the degradation of these nitrogen-containing compounds releases ammonia. Ammonia is toxic and must be removed. Fishes in water excrete ammonia as the major nitrogenous waste through gills, but gills of air-breathing fishes are modified for air-breathing or largely replaced by air-breathing organs. Notably, fishes emerged from water can no longer excrete ammonia effectively because of a lack of water to flush the gills. Hence, ancient fishes that participated in water-land transition must have developed means to deal with ammonia toxicity. Extant air-breathing fishes, particularly amphibious ones, can serve as models to examine adaptations which might have facilitated the emergence of ancient fishes from water. Some of these fishes can actively emerge from water and display complex behaviors on land, while a few can burrow into mud and survive for years during drought. Many of them are equipped with mechanisms to ameliorate ammonia toxicity during emersion. In this review, the mechanisms adopted by air-breathing fishes to deal with ammonia toxicity during emersion were organized into seven disparate strategies. In addition, eight extant air-breathing fishes with distinctive terrestrial behaviors and peculiar natural habitats were selected to describe in detail how these seven strategies could be adopted in disparate combinations to ameliorate ammonia toxicity during emersion.

Water management is a critical issue to be solved efficiently for an air-breathing direct methanol fuel cell (DMFC). The cell performance decreases sharply once the water flooding occurs. In this paper, a novel strategy of water removal is proposed by incorporating a functional self-made expanded metal mesh, which can be used as the cathode flow field in a DMFC. Experiments show that water can be directly discharged in the form of water film or water line from the water outlet to the bottom underneath the expanded mesh. The water management can be further improved by using absorbent cottons, suitable feed rates and an upright texture direction of the metal mesh. Results also show that only a few mesh openings are blocked by water when the tested device tilts from 60° to 120°. In a real DMFC, the expanded mesh displays an excellent ability in water removal compared to the traditional perforated flow fields. The cathode water only gathers at the bottom and covers very few mesh openings. This new method helps efficiently avoid the issue of water flooding at the cathode using the expanded mesh.

In this paper, a novel adaptive finite-time control of air-breathing hypersonic vehicles is proposed. Based on the immersion and invariance theory, an adaptive finite-time control method for general second-order systems is first derived, using nonsingular terminal sliding mode scheme. Then the method is applied to the control system design of a flexible air-breathing vehicle model, whose dynamics can be decoupled into first-order and second-order subsystems by time-scale separation principle. The main features of this hypersonic vehicle control system lie in the design flexibility of the parameter adaptive laws and the rapid convergence to the equilibrium point. Finally, simulations are conducted, which demonstrate that the control system has the features of fast and accurate tracking to command trajectories and strong robustness to parametric and non-parametric uncertainties.

Since most of the control strategies for air-breathing hypersonic vehicles (AHVs) concentrate on the control-oriented models built at/around a specific working point, it is somewhat hard to extend them to the broader flight envelop. Aiming at the above deficiency, this paper formulates the dynamics of AHVs as several sub-models, which switch to each other in accordance with the flight condition and make up of the control-oriented switched model (COSM). With the aid of the COSM, two adaptive tracking controllers are proposed for the purposes of velocity tracking and altitude tracking, sequentially. By utilizing neural networks and designing robust control laws, the possible changes on the force and moment coefficients in the COSM are successfully handled. The time-varying inertia parameters of AHVs are also considered at design level. It is worth emphasizing that while this strategy is developed based on a switched model, the resulting control algorithm is continuous with no connection to the switching signal. Analysis indicates that both velocity and altitude tracking errors remain small within the whole flight envelop, which is further confirmed by a simulation study.

In this paper, a novel constrained nonsingular fast terminal sliding mode control scheme based on adaptive neural network disturbance observer is proposed for a flexible air-breathing hypersonic vehicle in the presence of diverse disturbances and actuator constraints. Firstly, velocity and altitude subsystems in the strict feedback formulations are obtained by decomposing the longitudinal dynamics of flexible air-breathing hypersonic vehicle, while uncertainties with regard to flexible effects, aerodynamic parameter uncertainties, modeling errors, and external disturbances are formed as the lumped disturbances which are excellently estimated by the proposed adaptive neural network disturbance observer with the adaptive regulation laws of weight matrices. Then based on the nonsingular fast terminal sliding mode control, the proposed scheme integrated with adaptive neural network disturbance observer is developed to design the controllers with nonsingularity and fast convergent rate in order to provide robust and fast tracking performance of velocity and altitude. Furthermore, to tackle the saturation effects caused by the constraints of actuators, the auxiliary systems constructed in the proposed scheme are conducted to compensate the desired controllers timely. Lyapunov stability analyses prove that the stable tracking errors of velocity and altitude are bounded with the sufficiently small regions around zero even when flexible air-breathing hypersonic vehicle is subject to lumped disturbances and actuator constraints. Finally, the contrastive simulation results demonstrate that the proposed scheme provides the superior tracking performance and the effectiveness in tackling actuator constraints and counteracting lumped disturbances.

This paper addresses the fault-tolerant control issue for a class of flexible air-breathing hypersonic vehicles. Firstly, a longitudinal dynamic model with process faults is established, wh...

Mudskippers are amphibious air breathing fish with terrestrial adaptations in contrast to entirely aquatic fish. They are adapted to living on mudflats and show morphological, physiological, and behavioural features that could affect their phylogeny and phylogeography. A comparative genetic analysis was carried out on 100 specimens of the mudskipper Periophthalmus waltoni Koumans, 1941 from eight different sites along the coast of the Persian Gulf and Gulf of Oman. Phylogeographic inference based on two mitochondrial markers (Cyt b and D-loop) suggests that P. waltoni populations are divided into two well-divergent clades western and eastern. This is likely related to the geohydrological history of the area during the last Pleistocene glaciations. The regional phylogeographies are apparently also influenced by ecological and geographical barriers such as salinity, water current, and the geographic position of the Strait of Hormuz.

This study considers the design of a new back-stepping control approach for air-breathing hypersonic vehicle (AHV) non-affine models via neural approximation. The AHV's non-affine dynamics is decomposed into velocity subsystem and altitude subsystem to be controlled separately, and robust adaptive tracking control laws are developed using improved back-stepping designs. Neural networks are applied to estimate the unknown non-affine dynamics, which guarantees the addressed controllers with satisfactory robustness against uncertainties. In comparison with the existing control methodologies, the special contributions are that the non-affine issue is handled by constructing two low-pass filters based on model transformations, and virtual controllers are treated as intermediate variables such that they aren't needed for back-stepping designs any more. Lyapunov techniques are employed to show the uniformly ultimately boundedness of all closed-loop signals. Finally, simulation results are presented to verify the tracking performance and superiorities of the investigated control strategy.

The aim of the present study was to determine the roles of externally versus internally oriented CO2/H+-sensitive chemoreceptors in promoting cardiorespiratory responses to environmental hypercarbia in the facultative air-breathing fish, Chitala ornata (the clown knifefish). Fish were exposed to environmental acidosis (pH 6.0) or hypercarbia (ae 30 torr PCO2) that produced changes in water pH equal to the pH levels of the acidotic water to distinguish the relative roles of CO2 versus H+. We also injected acetazolamide to elevate arterial levels of PCO2 and [H+] in fish in normocarbic water to distinguish between internal and external stimuli. We measured changes in gill ventilation frequency, air breathing frequency, heart rate and arterial blood pressure in response to each treatment as well as the changes produced in arterial PCO2 and pH. Exposure to normocarbic water of pH 6.0 for 1 h did not produce significant changes in any measured variable. Exposure to hypercarbic water dramatically increased air breathing frequency, but had no effect on gill ventilation. Hypercarbia also produced a modest bradycardia and fall in arterial blood pressure. Injection of acetazolamide produced similar effects. Both hypercarbia and acetazolamide led to increases in arterial PCO2 and falls in arterial pH although the changes in arterial PCO2/pH were more modest following acetazolamide injection as were the increases in air breathing frequency. The acetazolamide results suggest that the stimulation of air breathing was due, at least in part, to stimulation of internally oriented CO2/H+ chemoreceptors monitoring blood gas changes.

Aim: Decannulation of tracheostomy in cases of traumatic quadriplegia is always a challenge due to respiratory muscle paralysis, chest infections, aspiration and need to care for sacral sores. Aim of this study was to identify and overcome the difficulties in decannulation of tracheostomy in cases of quadriplegia due to cervical spinal cord injury. Material and methods: This prospective observational study was carried out in a tertiary care Spinal Cord Injury Center of a Military Hospital. Ten cases of tracheostomized traumatic quadriplegics were evaluated over 3years. Decannulation was considered once there was normal gag reflex, effective cough, manageable aspiration, oxygen saturation above 90%, no serious pulmonary compromise and no need for bed sores surgery. The cases were followed up for further one year post-decannulation. Results: Eight cases could be decannulated successfully. Only two cases could not be decannulated due to feeble chest movement, ineffective Cough, lack of motivation and occasional aspiration. Conclusion: Cervical cord injury patients have difficult decannulation due to weak respiratory muscles, ineffective cough, aspiration, pulmonary pathology and bed sores. Respiratory muscle exercise, quantified peak cough pressure, assisted coughing, risk benefit approach in aspiration, healing of bed sores and team work are keys to successful decannulation

This work presents a global plasma model of a gridded air-breathing electric propulsion concept based on magnetized high-frequency plasma operating in the pressure range of 10−3 Pa to 1 Pa. We illustrate that the global plasma model reproduces the experimental measurements of the extracted current over two orders of magnitude in pressure. Consequently, we use the model to investigate the theoretical scalability of the plasma source, finding that the plasma source performance scales reasonably well with the average absorbed power per molecule, even though this scaling factor has its limits. The global model presented in this work is a model of a specific laboratory device and, in future, it can be adapted to very low Earth orbit conditions by adjusting the boundary conditions. The model was implemented using PlasmaSolve p3s-globalmodel software and the configuration file containing all the equations is provided to the community as supplementary material.

The jeju Hoplerythrinus unitaeniatus and the traira Hopliasmalabaricus are two neighboring genera from the family of erythrinid fish, both possessing a two-chambered physostomous swimbladder. In the jeju the anterior section of the posterior bladder is highly vascularized, and the swimbladder is used for aerial respiration; the traira, in turn, is a water-breather that uses the swimbladder as a buoyancy organ and not for aerial oxygen uptake. Measurement of swimbladder oxygen partial pressure (PO2) of fish kept at 26 °C in normoxic, hyperoxic (28–32 mg O2 L− 1) or hypoxic (1–1.5 mg O2 L− 1) water revealed constant values in traira swimbladder. Under normoxic conditions in the jeju swimbladder PO2 was higher than in traira, and the PO2 significantly increased under hyperoxic conditions, even in the absence of air breathing. In jeju, air-breathing activity increased significantly under hypoxic conditions. Hypoxic air-breathing activity was negatively correlated to swimbladder PO2, indicating that the swimbladder was intensely used for gas exchange under these conditions. In traira, the capacity of the ROS defense system, as assessed by measurement of activities of enzymes involved in ROS degradation and total glutathione (GSH + GSSG) concentration, was elevated after 4 h of hyperoxic and/or hypoxic exposure, although swimbladder PO2 was not affected. In jeju, experiencing a higher variability in swimbladder PO2 due to the air-breathing activity, only a reduced responsiveness of the ROS defense system to changing environmental PO2 was detected. © 2018, The Author(s).

The Indian air-breathing catfish, Heteropneustes fossilis faces various environmental constraints throughout the year leading to the problem of accumulation of toxic ammonia. Water restricted mud dwelling condition is a common environmental stress (desiccation stress) for catfishes in North Eastern India during winter. The fish is able to survive inside moist peat for months. In the present study the air breathing singhi catfish H. fossilis was kept inside mud peat for 30 days mimicking their normal habitat in winter and the changing pattern of free amino acid (FAAs) content was investigated in renal tissue. Under desiccation, a significant accumulation of ammonia and FAA, mainly glutamine, alanine, glycine, glutamate and serine have been observed in the renal tissue with approximately 2.56 and 1.56 fold increase. Thus, it appears that the Indian air-breathing catfish handle the ammonia toxicity by conversion of ammonia to some non-essential FAAs.

The dramatic transition to air breathing at birth represents a true challenge for the newborn infant mammal, a period in which neonatal respiratory diseases are common. Since the 1930s, fetal and newborn lambs have been the model of choice for whole-animal studies on neonatal respiration. The present review aims to illustrate the relevance of ovine models in studying the establishment of successful breathing at birth and its maintenance in the early postnatal period, as well as a number of abnormal conditions that can interfere with these processes.

The six-degree-of-freedom (six-DOF) modeling of air-breathing hypersonic vehicles (AHVs) is highly complex due to the variable flight conditions, structural elasticity and inherent aero-propulsive coupling. However, considering different modeling approaches, a significant amount of work has been reported in the area of AHV modeling. The aim of this paper is to investigate the six-DOF modeling of AHVs reported in the literature. Next, owing to the modeling uncertainties and coupled dynamics, state-of-the-art robust adaptive control design techniques have been presented for these models, which are also briefly reviewed in this paper. This survey also contains a small discussion on possible future advancements in the modeling and control of these vehicles.