Shock loss is the primary source of total pressure loss of transonic axial compressors. Reducing the shock by redesigning the geometry of rotor is of great interest for turbomachinery designers. However, the complex flow field involving shock waves, shock-boundary interaction, intense secondary flows, etc., in the compressor makes the design of rotor difficult. The conventional method of design and

This article deals with the problem of attitude tracking control for flexible satellite under flexible vibration disturbance, actuator fault and time delay. Based on disturbance observer and fault tolerant control techniques, the flexible vibration disturbance and actuator fault are effectively estimated by disturbance observer and fault estimation observer, respectively. Meanwhile, a delay-dependent

The traditional multi-objective efficient global optimization (EGO) algorithms have been hybridized and adapted to solving the expensive aerodynamic shape optimization problems based on high-fidelity numerical simulations. Although the traditional EGO algorithms are highly efficient in solving some of the optimization problems with very complex landscape, it is not preferred to solve most of the aerodynamic

The problem of modeling and controlling of a free-floating space manipulator with flexures in both links and joints is addressed in this study. A mathematical model of the system is developed by combining Lagrange’s equations and momentum conservation. The finite element method is introduced to discretize multi-links with complex cross-sections. In order to reduce the dimensions and maintain the precision

Position and velocity estimation using Global Navigation Satellite Systems (GNSS) has been widely studied and implemented. In contrast to existing GNSS, the idea of using low Earth orbit (LEO) satellites for position and velocity determination is relatively new. On one hand, the launch to LEO is more affordable compared to GNSS orbits. On the other hand, LEO satellites provide reduced coverage and

In this article, motor failure control of a six-rotor electric vertical take-off and landing (eVTOL) urban air mobility aircraft is investigated using adaptive model predictive control (MPC) based on the linear parameter-varying (LPV) model developed using the nonlinear rigid-body aircraft model. For capturing the aircraft dynamics under motor failure conditions, a family of linearized models are obtained

The cavitation performances and its internal flows in a centrifugal turbopump with and without a three-bladed axial inducer have been studied both experimentally and numerically. A 3D steady numerical model has been applied to simulate the cavitating flow from the inlet to the outlet ducts of the turbopump with and without an inducer by using ANSYS CFX code. In the present work, to clarify this relationship

In order to automate the ground maneuvering of a civil regional aircraft and improve the efficiency of the air transport system, a fly-by-wire nose wheel steering system (NWSS) was designed. A rack and pinion steering mechanism integrated with a single actuator mechanism was proposed. The basic control circuit diagram with integrated test, the electro-hydraulic system diagram, and the mathematical

This article investigated the stability of transverse hydrogen injection combustion caused by the plate vibration. The finite-rate method is used to simulate the combustion. The unsteady flow field in the unstable phase of combustion is extracted. The unstable mode of the shock wave structure and the flame structure during the stage of combustion instability, the spatial and temporal characteristics

This two-parts article introduces a novel hybrid propulsion system based on the DEA compressor. The system encompasses a Pulse Detonation TurboDEA as the master engine that supplies several full-electric ancillary thrusters called DEAThruster. The system, called the propulsion set, can be categorized as a distributed propulsion system based on the design mission and number of ancillary thrusters. Part

The Moon Village and similar concepts are strongly reliant on in situ resource utilisation (ISRU). There is great interest in harvesting solar power using locally leveraged in situ resources as an essential facet of in situ infrastructure. Traditionally, silicon-based photovoltaic cells have been assumed, preferably manufactured in situ using a 3D printing rover, but there are major difficulties with

This article introduces a novel full-electric aircraft propulsion designed based on the DEA compressor, named DEAThruster that is supplied by a PEMFC. The thruster designed and modeled in this study is a compact DEAThruster to operate in altitudes up to 15,000 m and in the subsonic/transonic region with a specific thrust around 8300 N s/kg. The results show the thruster can satisfy all expectations

An engineering approach is presented to analyse the asymmetric blade thrust effect with the help of analytical and semi-empirical methods. It is shown that the contribution of the asymmetric blade thrust effect in the lateral-directional stability of multi-engine propeller-driven aircraft is significant particularly in critical flight conditions with one engine out of service. Also, in some cases where

In this article, a sliding mode control–based nonlinear guidance scheme for controlling both impact angle and impact time simultaneously is proposed. The problem of impact angle control is first transformed to that of controlling line-of-sight angle and its rate, while the requirement of impact time is achieved by tracking the desired time-to-go. The chosen time-to-go estimate accounts for the curvature

Nonlinear control of turbofan engines in the flight envelope has attracted much attention in consideration of the inherent nonlinearity of the engine dynamics. Most nonlinear control design techniques rely on the correction theory of reference model parameter to extend the typical flight operations from ground operation. However, dynamic uncertainties in flight envelope lead to the deviation of operating

An atmosphere-breathing electric propulsion system uses the rarefied atmospheric molecules as the propellant for the electric thruster. In the best case, it can allow spacecraft complete a long-time mission in the lower Earth orbit without carrying any propellant. In this article, the intake geometry is designed, analysed and optimized to improve the performance of atmospheric particles capture, including

Two-dimensional numerical simulations of a rotating detonation combustor (RDC) fueled by ethylene–oxygen–nitrogen were performed to investigate the evolution process of multiple rotating detonation waves (RDWs), that is, initial chaotic stage, self-adjustment stage, and the final stable stage. The number of stable RDWs corresponding to the initial conditions was in good agreement with that predicted

This study aims to develop an advanced integral terminal sliding-mode robust control method using a disturbance observer (DO) to suppress the forced vibration of a large space intelligent truss structure (LSITS). First, the dynamics of the electromechanical coupling of the piezoelectric stack actuator and the LSITS, based on finite element and Lagrangian methods, are established. Subsequently, to constrict

Optimization method, as a promising way to improve inlet aerodynamic performance, has received increasing attention. The present research is undertaken to design a two-dimensional axisymmetric hypersonic inlet using parametric optimization. The inlet configuration is parameterized and optimized in consideration of total pressure recovery and starting performance. A Pareto front is obtained by solving

An unsteady aerodynamic surrogate model based on the deep LSTM (long short-term memory) network is proposed for predicting unsteady aerodynamic coefficients. Deflection angles and deflection velocities of control surfaces are introduced to input values of the surrogate model to enhance the capability of identifying different motion states so that accumulative error can be controlled. Longitudinal stability

Time accurate numerical simulations were conducted to investigate the effect of triangular cavities on the unsteady aerodynamic characteristics of NACA 0012 airfoil at a Reynolds number of 50,000. Right-angled triangular cavities are placed at 10%, 25% and 50% chord location on the suction and have depths of 0.025c and 0.05c, measured normal to the surface of the airfoil. The second-order accurate

This two-part article introduces a novel hybrid propulsion system based on the DEA compressor. The system encompasses a Pulse Detonation TurboDEA as the master engine that supplies several full-electric ancillary thrusters called DEAThruster. The system, called the propulsion set, can be categorized as a distributed propulsion system based on the design mission and number of ancillary thrusters. Part

This article deals with the issue of designing a flight tracking controller for an unmanned aerial vehicle type of quadrotor based on an optimal model-free fuzzy logic control approach. The main design objective is to perform an automatic flight trajectory tracking under multiple model uncertainties related to the knowledge of the nonlinear dynamics of the system. The optimal control is also addressed

To address the issue that multiple missiles intercepting a highly maneuvering target simultaneously with desired angles, a novel cooperative guidance law based on the decoupled model in the line-of-sight (LOS) and normal LOS direction is proposed in LOS frame. However, there is control coupling in the two directions of the cooperative guidance model. In this article, we first decouple the guidance

This article proposes a numerical investigation into the internal flow structure in the supersonic expander-rotor (SER). In order to reveal internal flow mechanism, the significant influencing factors in the flow structure are identified, and the solutions to improving the integrated performance of the SER are developed. According to the numerical results, the wave structure of the expansion wave and

The in-service loadings on the landing gear are usually complex and from different directions, which lead to the fatigue critical locations in the landing gear structure mostly in multiaxial stress state. A methodology based on the critical plane method was proposed for estimating the fatigue lifetime of outer cylinder of the main landing gear undergoing variable amplitude (VA) multiaxial proportional

This article introduces an original model-based design methodology addressing a high-performance aircraft design challenge: conflicting performance requirements. The case study of the Global 7500 elevator actuation system also provides in-depth insight into the complex design process of today’s fly-by-wire flight control systems. The methodology presented here redefines the aircraft manufacturer’s

In launch vehicles, cryogenic propulsion stages store liquid oxygen (LOX) at 76 K and liquid hydrogen (LH2) at 20 K, generally in two separate insulated tanks connected through tubular truss components. Consequently, load transfer from the LH2 tank to the LOX tank is very much localized, resulting in a nonoptimal design. This article presents an alternative single tankage design using a common bulkhead

This article presents an analytical framework for investigating the cruise performance of conventional helicopter configurations. Starting from the analysis of power required in straight-and-level flight, endurance and range performance of turbine- and battery-powered rotorcraft are considered, for which it is assumed that fuel consumption and constant-power battery discharge models are, respectively

Various Kalman filter approaches have been presented for performance estimation of aircraft engines provided that sensor measurement numbers are sufficient and all of them are available. However, it is difficult to collect all physical parameters along the gas path since the complex structure limits sensor installation, especially around the high-pressure turbine. The contribution of this article is

The article studies the fault diagnosis of the first-stage power system of a carrier rocket made up of multiple engines. It establishes the simplified 6-DOF nonlinear model and uses the extended Kalman filter to generate residual errors. The quadratic receding time-domain algorithm is used to detect faults, and estimation vector fault characteristics are used to estimate precisely the thrust loss degree

This article examines the fundamental aspects of controlling ground resonance in rotorcraft equipped with actively controlled landing gear. Ground resonance is a mechanical instability affecting rotorcraft on the ground. It occurs at certain rotor speeds, where the lead–lag motion of the rotor couples with the motion of fuselage creating a self-excited oscillation. Typically, passive or semi-active

As a propulsion system for vertical take-off and landing (VTOL) aircraft, the gas-driven fan propulsion system has received some attention in recent years due to its simple mechanical structure and good performance. During the operation of the propulsion system, the core turbofan exhaust is directed to the tip turbine to drive the ducted fan to obtain thrust, and the louvered vector exhaust device

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized

Despite 50 years of technological advancement since the inception of Concorde, research on supersonic passenger aircraft has only recently resulted in design and flight test of several small 12- to 55-passenger business jets with supersonic cruises between Mach 1.2 and 2.2. Analytical research designs of larger 300-passenger aircraft have been conducted only to speeds of Mach 2.0 and 2.2, mainly avoiding

In order to study the radar characteristics of blunt-hub rotor, a dynamic scattering method (DSM) based on physical optics and physical theory of diffraction is presented. Important influencing factors are analyzed and discussed, including rotor disk inclination, azimuth, elevation angle, and radar wave frequency. The radar cross section (RCS) of the blunt-hub rotor is used for comparison with conventional-hub

The present article deals with the conceptual design of a new medium short takeoff and landing tactical transport aircraft, which is intended to expand the institutional capabilities of the Colombian Air Force in terms of versatility and flexibility. An original design strategy was developed during the conceptual design, combining classical methodologies and high-fidelity computational fluid dynamics

Experimental structural response of equipment mounted in store carried externally by jet type aircraft is investigated, predicted and compared with responses suggested by military standards in this study. A representative store which is similar to Mark-83 warhead with guidance units in terms of mass and geometry is used in this study. The main scope of this study is to evaluate the structural response

Helicopter rotor performance can be significantly altered by ice accretion which directly degrades the handling qualities and safety during flight. To obtain understanding into the effect of ice accretion on a helicopter rotor in forward flight under different icing environments, an experimental campaign was conducted in an icing wind tunnel using a rotor model with diameter at 2 m. Research was emphasized

Moving mass flight vehicle is a strongly nonlinear system under high speed flying conditions. The system attitude dynamics becomes even more complex due to the coupling between the internal moving mass with large mass ratio and the vehicle body. This article investigates the open-loop nonlinear dynamics of a novel flight vehicle with pitch-control single moving mass from the prospective of bifurcation

The effect of pressure gradient on a separated boundary layer past the leading edge of an airfoil model is studied experimentally using electronically scanned pressure (ESP) and particle image velocimetry (PIV) for a Reynolds number (Re) of 25,000, based on leading-edge diameter (D). The features of the boundary layer in the region of separation and its development past the reattachment location are

In this study, we propose new adaptive laws for adjusting the controller parameters of the model reference adaptive control (MRAC) and MRAC with integral feedback schemes. The innovation presented in this study is considering a new form for the Lyapunov function candidate to prove the stability of the closed-loop system. In general, a Lyapunov function candidate contains two sets of quadratic expressions

A wing is an important part of the aircraft to improve aerodynamic performance. The current study is focused on an adaptive surrogate algorithm for airfoil aerodynamic optimization, which is based on a multi-output Gaussian process model. The conventional design method seriously relies on wind tunnel experiments and expensive computational simulations. The metamodels can significantly improve design

Several linearly nonuniform clearances have been designed to explore a novel strategy for attenuation of leakage flow in tip region of high loading transonic rotor and the effects of axially nonuniform clearance on detailed tip flow structure and stable operating range of rotor have been discussed as well. The results showed that the tip flow characteristic of rotor is affected mainly by the combined

This article proposes a computationally efficient adaptive robust control scheme for a quad-rotor with cable-suspended payloads. Motion of payload introduces unknown disturbances that affect the performance of the quad-rotor controlled with conventional schemes, thus novel adaptive robust controllers with both integer- and fractional-order dynamics are proposed for the trajectory tracking of quad-rotor

This article proposed an extended state observer (ESO)–based output feedback control scheme for rigid spacecraft pose tracking without velocity feedback, which accounts for inertial uncertainties, external disturbances, and control input constraints. In this research, the 6-DOF tracking error dynamics is described by the exponential coordinates on SE(3). A novel continuous finite-time ESO is proposed

Based on the equal-intensity shock theory, this article designed a supersonic inlet working in Mach number 3.0∼5.5 with the background of an air-breathing engine. The inlet applied the four-shock train mixed compression configuration and inserted a sidewall compression at the beginning of the isolator. Through developing effective 3D RANS computations validated by current experiments, the performance

Low swirl combustion (LSC) technology has the advantage of ultralow NOx emissions, which is of great significance to the development of low-emission gas turbine engines in the future. To investigate the flow field and flame structure characteristics of LSC, a test rig of low swirl burner was designed and developed. Particle image velocimetry measurement results show that the location and size of the

This study investigated associations of attitude tracking control of an underactuated spacecraft with consideration of saturation and perturbations. A nonsingular attitude tracking control was proposed which did not need limiting initial conditions of the quaternions. The controller was analyzed based on Lyapunov criteria and LaSalle’s invariance theorem in the large-angle maneuver. In order to control

Closed-loop attitude steering is a concept for implementing an attitude trajectory by using a conventional quaternion error feedback controller to track the time-varying attitude reference, rather than to simply regulate to a desired orientation. This is done by sampling the reference input and executing the maneuver as a sequence of closely spaced regulating commands that are read out from the spacecraft’s

This article proposes an impact-time-control guidance law that can keep a non-maneuvering moving target in the seeker’s field of view (FOV). For a moving target, the missile calculates a predicted intercept point (PIP), designates the PIP as a new virtual stationary target, and flies to the PIP at the desired impact time. The main contribution of the article is that the guidance law is designed to

Any aircraft in flight is subjected to dynamic loads. Following vibration-related accidents, a flow field and vibration analysis can be carried out to analyze the data and study the cause of the accident. When slit airflow enters the cavity between the tailplane structure and the elevator, a mixed vortex is formed. If the vortex-induced vibrational frequency of around 50 Hz happens to be close to the

The pre-swirl system is of great importance for temperature drop and cooling air supply. This study aims to investigate the influencing mechanism of heat transfer, nonuniform thermodynamic characteristics, and cooling air supply sensitivity in a pre-swirl system by the application of the flow control method of the pre-swirl nozzle. A novel test rig was proposed to actively control the supplied cooling

The decrease of stress amplitude is generally believed as the mechanism of fatigue life enhancement in interference fit joints under cyclic loading for each load cycle. In order to exactly estimate it, a new analytical model was presented. In this model, influences of mass, geometry, and plastic deformation are considered to modify and improve the spring model, and, moreover, the stress amplitude at

This article proposes a novel adaptive fault-tolerant control method for suppressing flutter and compensating for related failure in a flutter system. Considering cubic nonlinearity, external disturbances, and related failure, the flutter dynamic model was established firstly. Then, an adaptive fault-tolerant control law was proposed on basis of this model to compensate for related failure and suppress

A new experimental technique has been developed to measure the pressure distribution over the surface of a rotating model in a wind tunnel for various spin rates, free-stream Mach numbers, and angles of attack. In this method, all of the measuring instruments are placed inside the rotating model which eliminated previous operational limitations and technical problems associated with attempts to measure

This study is mainly focusing on the problem of spacecraft close-range proximity with obstacle avoidance in the presence of complex shape. A novel Gaussian mixture model–based nonsingular terminal sliding mode control (GMM-NTSMC) is proposed. This is achieved by developing GMM-based potential function with a switching surface of NTSMC. It is theoretically proved that the closed-loop system is globally

Non-reflecting boundary conditions are crucial for aeroacoustic simulations to prevent non-physical reflections at boundaries from contaminating the interior acoustic solutions. Various non-reflecting outflow conditions, mainly based on the characteristic theory, have been developed. By using a locally one-dimensional inviscid approximation, the characteristic wave amplitudes are identified as the

This article handles the issue of fault-tolerant control of a quadrotor unmanned aerial vehicle (UAV) in the existence of sensor faults. A general non-linear model of the quadrotor is presented. Several non-linear Kalman filters namely, the extended Kalman filter, the unscented Kalman filter and the cubature Kalman filter (CKF) are utilized to estimate the states of the quadrotor and to compare the

The online cooperative path planning problem is discussed for multi-quadrotor maneuvering in an unknown dynamic environment. Based on the related basic concepts, typical three-dimensional obstacle models, such as spherical and cubic, and their collision checking criteria are presented in this article. An improved rapidly exploring random tree (RRT) algorithm with goal bias and greed property is proposed