Journal of Aerospace Engineering

This paper is concerned with the development of a new measurement device for the realistic assessment of braking capability of landing airplanes for winter runways. The conventional and current practice of runway condition monitoring has been focused on identifying the maximum tire-pavement frictional drag ($\mu$ value) and often neglected the characteristics of actual aircraft braking systems as well as the comprehensive effects coming from various factors such as deformable contaminants on the winter runway. The braking availability tester (BAT) proposed in this paper is designed to take a different approach for the realistic assessment of braking availability of landing airplanes. The main idea of the BAT is to mimic the braking operation of actual aircrafts as closely as possible by incorporating the same brake mechanism and antiskid braking system (ABS) used in existing aircrafts. In doing so, the BAT also incorporates a suite of sensors for monitoring the status of braking operation in real time. This paper details the design concepts and operation principles of the BAT. Preliminary test results are also presented to verify the main functionality of the BAT.

Acoustic imaging is an indispensable experimental aid in the design of silent aircraft. In this work, acoustic imaging is performed in a classical closed-section wind tunnel that has been extensively modified using specifically designed liners on the walls of the test section. The details of the associated acoustic modification and the aeroacoustic imaging method are introduced in this paper. The acoustic test performance is carefully evaluated by examining background noise reductions and acoustic beamforming results. The experimental outcomes suggest that the proposed acoustic modification could suppress background noise by 5 dB at $40–80\mathrm{m}/\mathrm{s}$ test flow speeds. The beamforming results clearly identify the dominant airframe noise sources at landing gears and high-lift devices. The experimental results agree fairly well with the preceding computational and empirical predictions. The proposed acoustic imaging technique has been shown to be an effective experimental technique in identifying airframe noise sources. In addition, the acoustic treatments developed in this paper could be considered in extending the aeroacoustic capabilities of existing closed-section wind tunnels.

This article deals with the design optimization of truss structures with discrete design variables, which remains quite a challenging task in structural design. A new discrete search strategy based on the recently developed subset simulation optimization algorithm is proposed in detail for this type of structural optimization. The discrete design variables are transformed into standard normal variable space to implement the sampling procedure in subset simulation optimization, while the optimization is processed in the discrete design space in the mean time. The performance of the proposed method is illustrated by four representative benchmark optimization problems. Comparisons are made with other well known stochastic optimization algorithms. It is found that the proposed method can produce optimum designs as good as or better than those of other stochastic optimization algorithms.

This paper describes three-dimensional (3D) grain shape characteristics of returned lunar soil (No. 60501) and its numerical simulation by using the image-based discrete-element method (DEM). First, the lunar soil sample was investigated by X-ray computed tomography (CT) at the SPring-8 facility. Next, the obtained grain shapes were modeled by an original technique based on a clumped sphere method. The CT images were processed by an originally developed image analysis, and 74 grains were identified. Based on their 3D shapes and intraparticle voids and cracks, the grains were classified into four categories: (1) agglutinate (ag), (2) breccia type A (brA), (3) breccia type B (brB), and (4) plagioclase (pl). The content ratio of each grain category favorably agreed with those reported in previous studies. The 3D shape indices, namely, the aspect, flatness, and elongation ratios; the Krumbein’s sphericity; and the newly proposed volume ratio to ellipsoid were computed for 74 grains. Evaluating the differences in grain shape among the four categories, it was found that ag grains were considerably more angular (irregular) than grains belonging to the other categories. The volumes of the internal voids and cracks in the four categories were also quantitatively evaluated. There is no production of ag grains on Earth because the atmosphere prevents micrometeorite impacts. Although the effect of ag grains on the bulk properties of lunar soil should be evaluated, mechanical experiments may damage the lunar soil grains. Thus, the authors used computer simulations via image-based DEM. The grain shapes were modeled by clumping 10 spheres in the image-based DEM simulations. The effect of ag content on the dynamic (angle of repose) and quasistatic (simple shear) behaviors of the grain assembly were evaluated in a series of image-based DEM simulations. In simulations of $\mathrm{ag}=0\%$, $\mathrm{ag}=27\%$, and $\mathrm{ag}=100\%$, the $\mathrm{ag}=100\%$ specimens developed the largest angle of repose. In addition, it was found that the ag content primarily affects the bulk density compared with the shear strength. This work is important for understanding the mechanical properties of lunar soils because simulation methods offer a suitable alternative to mechanical experiments, which may damage the specimens.

This paper presents the development of an efficient time-marching simulation technology for fluid-structure interaction applications using commercial computational fluid dynamics (CFD) and computational solid mechanics (CSM) software and in-house modules. By splitting the multidisciplinary coupling problem into three major analysis fields (the fluid field, the structure field, and the moving mesh pseudofield) one can solve each field using already available and validated software and the coupling between the different analysis fields can be accomplished by in-house software (FORTRAN and C codes). This simulation technology is able to predict both unsteady interaction phenomena and nonlinear aeroelastic problems in reasonable time, taking advantage of a high-performance computing network. Commercial CFD software was used to solve the Navier-Stokes equations and the chosen turbulence models of the fluid field while the structural field was solved using commercial CSM software. The transfer of information from the fluid field to the structural field and vice versa is computed by an in-house interpolation module, which reduces the user interaction to a minimum initialization. The third field, the moving mesh, was solved with another in-house code, which employs the spring network analogy and the elastic material analogy. The advancement of the solution is controlled by means of FORTRAN and C codes that manage the run/wait conditions of software modules based on the staggered procedures proposed in previous research. The proposed aeroelastic simulation technology was validated with the experimental data available for the advisory group for aerospace research and development (AGARD) 445.6 standard aeroelastic configuration for dynamic response at subsonic and transonic free stream Mach numbers.

The objective of this paper is to investigate how the aeroelastic stability, particularly flutter, is affected by aircraft maneuvers. The authors’ investigation is based on a comprehensive mathematical model of aircraft, which is achieved by seamlessly integrating all the disciplines pertinent to flight of aircraft. The aircraft is treated as an unstrained, flexible multibody system subject to unsteady aerodynamics. The bodies are fuselage, wing, and horizontal and vertical stabilizers, whose structures are modeled as beams in bending and torsion. The equations of motion are derived using Lagrange’s equations in quasi-coordinates. The resulting equations are a set of nonlinear ordinary differential equations of relatively high order. The final model is used to determine flutter speeds of aircraft at steady level turn and steady climb at various altitudes. These maneuvers are especially chosen to keep the equations time invariant. The numerical results are given for a generic transport model (GTM). The stability of a GTM is affected by turn radius, climb angle, and altitude. The results for climbing flight can be extended to address stability of gliding flight.

Selective assembly is a cost-effective approach for reducing the overall variation and thus improving the quality of an assembled product. Traditional selective assembly requires quite a large number of finite-element analysis (FEA) runs and consequently is rather time consuming when considering every part’s deviations. The paper presents the highly efficient selective assembly method that assists operators in horizontal stabilizer assembling while considering the parts’ fabrication deviations. Metamodeling is employed to build the input–output functions from FEA results. The hybrid metamodel consisted of four metamodels and is constructed to express the mapping relationship between fabrication deviations and assembly distortions. Cross validation of metamodels is conducted using 27 FEA simulations. The quantitative selective assembly suggestion, that is, the selective assembly table, is obtained using the hybrid metamodels and particle swarm optimization (PSO) algorithm. The optimal assembly of the trailing edge is considered to illustrate the computational efficiency of the method. The results have shown that the proposed method preserve final assembly precision with high efficiency. The selective assembly procedures outlined in this paper will enhance the understanding of the compliant components deformation in assembly and help systematically improving the precision control efficiency in the civil aircraft industry.

Given the advantages of variable specific impulse (VSI) engine, it is very likely that in the future there will be deep space missions that use this thrust as propulsion system. In this study, a design technique for a fuel optimal Earth-to-Halo transfer using VSI is proposed. The calculus of variations approach and direct parameter optimization are combined to formulate the trajectory optimization problem. The classic stable manifold, developed in dynamical systems theory, is employed to further reduce fuel consumption. Adjoint control transformation (ACT) and analytical gradients are incorporated to improve performance of the algorithm. Four transfer examples—direct transfers from 500 km low Earth orbit (LEO) and 3,629 km medium Earth orbit (MEO) to lunar L1 halo orbit—and indirect transfers with lunar flybys, are presented.

The inflation process of a special parachute with slots and a fixed payload is investigated using a multimaterial arbitrary Lagrangian-Euler–coupled numerical approach, which considers fluid-structure interaction within the LS-DYNA nonlinear analysis code. The transient dynamic solver is set up using a Lagrangian-Euler penalty method, and a numerical simulation of the slot parachute design that considers permeability is performed. The inflation characteristics of a slot parachute at different initial velocities are analyzed. The three-dimensional simulation results for the inflation are validated by comparing with the airdrop test results. Finally, the incompressible fluid dynamics and the evolution of vortexes during the opening process are analyzed. The results demonstrate the following. This slot parachute can rapidly attain a steady state after fully inflating without any obvious canopy breathing. The stress distribution near the slots is obviously higher than the average level across the canopy surface. A symmetrically counterrotated vortex couple appears at the top of the parachute, which then extrudes to asymmetry until the couple separates and is brushed off by the airflow.

In this paper, an approach is developed for active vibration control of flexible rectangular plate structures using control theory. The flexible rectangular plate system is first modeled through a new type of modeling method—discretization and reduced-order modeling method (DROMM); and second, the validity of the obtained new model is investigated by comparing the plate natural frequencies, static analysis, and forced vibration response analysis between a finite-element model and the new model. After validating the model, an adaptive fuzzy sliding mode multiple-input multiple-output (MIMO) controller is applied to the plate dynamic equation through the MATLAB/Simulink platform. The simulation and experimental results clearly demonstrate an effective vibration suppression capability that can be achieved using an adaptive fuzzy sliding mode MIMO controller.

This paper presents kinematically coupled relative spacecraft motion control in the close proximity of a tumbling target using the state-dependent Riccati equation method for proximity operation mission. In general, a rigid-body dynamics can be expressed as both translation and rotation about the center of mass. However, a kinematic coupling between the rotational and translational dynamics occurs when it is not expressed about the center of mass. Thus, kinematically coupled relative spacecraft motion model is derived to describe the relative motion about the selected arbitrary points on both the target and spacecraft. Then, spacecraft relative motion is represented by combining the relative translational and rotational dynamics of arbitrary points on the spacecraft. The spacecraft is required to achieve the desired position and attitude to track a tumbling spacecraft quickly in the effect of kinematic translation and rotation coupling. The state-dependent Riccati equation method is implemented to design a nonlinear controller in six degrees of freedom. Numerical simulation results validate kinematically coupled relative spacecraft motion control with respect to a tumbling target.

An efficient failure analysis of laminated composite and sandwich cylindrical shell is done for the first time using an efficient $C_0$ finite-element (FE) model based on higher-order zigzag theory (HOZT). The FE implementation based on HOZT to study the failure of composite and sandwich shells incorporating all three radii of curvature is presented. The proposed two-dimensional (2D) FE model satisfies the interlaminar shear stress continuity at the layer interfaces and also ensures zero transverse shear stress conditions at the shell top and bottom. The problem of $C_1$ continuity associated with the HOZT is circumvented by using an appropriate $C_0$ FE formulation. The piecewise parabolic shear stress variation across thickness of each layer is considered and hence, shear deformation is accurately modeled for composites and sandwich shells. The failure load results for laminated composite and sandwich shells obtained by using the present 2D FE model are quite close to the 3D elasticity results. Many new results are presented by varying different parameters which should be useful for future research.

Advanced navigation systems for pinpoint landing are required in the Mars entry, descent, and landing (EDL) phases. Some new high-precision EDL navigation technologies based on beacons have been presented; however, the measurement bias errors of the beacons—range, position, and velocity errors—have not been considered in the past, which may lead to severe degradation in filtering process. The lack of navigation accuracy may result in a large growth of spurious navigations. In this paper, the Schmidt-Kalman filter is formulated for mitigating the effects of the systematic bias errors. This filter incorporates statistics of measurement errors into the system formulation; instead of only estimating them, it considers the cross correlation between the states and the measurement bias errors, leading to a realistic covariance estimate. Additionally, the UD decomposition is implemented in the Schmidt-Kalman filter to avoid the matrix inversion operation and ensure the numerical stability of the filtering. Monte Carlo simulation results are presented to demonstrate good performance of the Schmidt-Kalman filter with UD decomposition for navigation during the Mars entry. The Schmidt-Kalman filter not only refrains from the divergence of the filtering but also significantly improves the state accuracy.

A postbuckling analysis is presented for functionally graded material (FGM) cylindrical panels resting on elastic foundations subjected to axial compression under heat conduction. Two kinds of micromechanics models, namely, Voigt model and Mori-Tanaka model, are considered. The material properties of FGMs are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents and are assumed to be temperature-dependent. The formulations are based on a higher-order shear deformation theory with a von Kármán-type of kinematic nonlinearity. The panel-foundation interaction and thermal effects are also included. The nonlinear prebuckling deformations and initial geometric imperfections of the panel are both taken into account. A singular perturbation technique along with a two-step perturbation approach is employed to determine the buckling loads and postbuckling equilibrium paths. The effects of volume fraction index, temperature variation, foundation stiffness, panel curvature ratio as well as the in-plane boundary condition of straight edges on the postbuckling behavior of FGM cylindrical panels are discussed in detail.

In this paper, the influences of strake wing on unsteady characteristics of aircraft at high angle of attack during rolling oscillation, yawing oscillation, and coupled motion at different frequencies is investigated by using a forced oscillation test rig. The experiments include dynamic force and flow field measurements. As the results show, the rolling moments are affected by the vortices generated by the strake wing. The rolling moment is large and shows strong hysteresis both in the rolling and yawing oscillations. The value of the rolling moment coefficient is small in the coupled motion. The change of the rolling moment is related to the unsteady development of the strake vortices. The characteristics are almost the same for the yawing moment, which may mainly be affected by the sideslip angle. This paper is for the aerodynamic configuration design and the flight control design using flow control method.

In order to obtain the lunar lander soft landing performance impact caused by the body gravity centerline shift, a seven-degree-of-freedom dynamic model is established based on the inertia force, and a dynamics and kinematics equation is deduced. The dynamic model was verified by the lunar lander scale model and soft landing impact experimental platform. Soft landing performance effects caused by the lander body gravity centerline shifts are analyzed according to the displacement of the body, the body overload, primary/secondary pillar load, and buffer processes. The research results show that the gravity centerline shift has a significant influence on the lunar lander soft landing performance; when the lunar lander lands on the lunar slope—in a downward direction along the slope—the appropriate shift of the position of the gravity centerline can effectively improve the soft landing performance and stability.

It is widely recognized that future exploration missions to the Moon will include construction of permanent lunar bases to support long-term lunar missions. The lunar in situ resource utilization concept to produce superior construction materials is a vital part of exploration missions. This paper presents a novel approach for consolidation of lunar regolith with activated thermite reactions using aluminum or magnesium-polytetrafluoroethylene (PTFE) systems to produce superior ceramic materials for potential construction purposes on the Moon. Thermodynamic analysis of reactive systems was used to predict the adiabatic temperature and equilibrium product concentrations. It was demonstrated that PTFE up to 2% by weight is sufficient to achieve regolith consolidation and reduce aluminum (magnesium) content to 15% by weight with utilization of more than 80% by weight regolith. Testing of fabricated materials shows that consolidated ceramics can have up to 60% porosity, which significantly improves thermal insulation up to $0.1\mathrm{W}/\mathrm{mK}$. The hardness value of the material—approximately 850 in the Knoop scale—confirms that consolidated regolith can accomplish the construction requirements on the Moon.

The Charpy transverse impact experiments on the three-dimensional (3D) multiaxial warp knitted (MWK) composites with four fiber architectures are performed at room and liquid nitrogen temperatures (-196°C). Macrofracture morphology and scanning electron microscope (SEM) micrographs are examined to understand the impact deformation and failure mechanism. The results show that the transverse impact properties can be affected greatly by the fiber architecture and decrease significantly with the increase of 90° fibers at room and liquid nitrogen temperatures. Meanwhile, the impact energy at liquid nitrogen temperature has been improved significantly than that at room temperature. Moreover, the fiber architecture is an important parameter affecting the transverse impact damage and failure patterns of composites at room and liquid nitrogen temperatures. At liquid nitrogen temperature, the matrix solidification and interfacial bonding is enhanced significantly. However, more local microcracks occur and damage accumulation increase, especially for the materials with 90° fibers. In addition, the brittle failure feature becomes more obvious at liquid nitrogen temperature.

This paper presents a tracking control problem of a flexible air-breathing hypersonic vehicle with aerodynamic uncertainty. The flight control design is challenging because of heavily coupled propulsive, aerodynamic forces and flexibility effects. A control-oriented model is derived where the flexible dynamics are regarded as perturbations and the aerodynamic uncertainty is included. It does not need to be transformed into a linear parameterization formulation. Based on an analysis of it, it is decomposed into a velocity subsystem and an altitude subsystem. Then dynamic inversion and a sliding mode control are combined to design the controller of the velocity subsystem. In addition, the sliding mode control and adaptive control are incorporated into a backstepping control architecture to develop the controller for the altitude subsystem after it is transformed into approximately strict-feedback form. The upper bounds of the uncertain terms do not need to be known in advance. They are estimated online, and the estimated values are updated by adaptive laws. Time derivatives of virtual control inputs are taken as uncertain terms to eliminate the so-called explosion-of-terms problem in traditional backstepping control. Simulation results demonstrate the performance of the proposed control scheme, which achieves stable tracking of the reference trajectories.

This paper develops and models the compliant spar concept that allows the wingspan to be varied to provide roll control and enhance the operational performance for a medium altitude, long endurance (MALE) UAV. The wing semispan is split into morphing partitions and the concept may be incorporated in each partition; however, only the tip partition is considered here. The compliant spar is made of compliant joints arranged in series to allow the partition to be flexible under axial (spanwise) loads, but at the same time stiff enough to resist bending loads. Each compliant joint consists of two concentric overlapping AL 2024-T3 tubes joined together using elastomeric material. Under axial (spanwise) loading, the elastomeric material deforms in shear, allowing the overlapping distance between the tubes to vary and hence the length (in the spanwise direction) of the joint/spar to vary. High fidelity modeling of the concept is performed. Then, structural design optimization studies are performed to minimize the axial stiffness and the structural mass of the concept for various design constraints. The flexible skin and actuation system to be used are also addressed.

The present study deals with the dynamic stability behavior of laminated composite and sandwich plates subjected to in-plane static and periodic compressive loads based on a recently developed inverse hyperbolic zigzag theory by the authors. The present model satisfies the traction-free boundary conditions on the surfaces of the plate and interlaminar continuity conditions at the layer interfaces, thus obviating the need for a shear correction factor. An efficient $C^0$ continuous isoparametric serendipity element with seven field variables is employed for the usual discretization of the plate structure. The effect of span-thickness ratio, modular ratio, boundary conditions, static load factor, and thickness ratios are examined by solving a variety of numerical problems on laminated composite and sandwich structures. The principal instability regions of plate structures are obtained using Bolotin’s approach and are represented either in the nondimensional load amplitude-excitation frequency plane or load amplitude-load frequency plane. The evaluated results are compared with the available published results based on various deformation theories. The prediction of accurate results at the cost of less computational effort ensures the efficiency of the present models for a wide range of applications.

Parks containing manufactured homes and trailers exist in the hurricane-prone areas of the southern United States. Homes in these parks may suffer heavy damage from high-speed winds. This paper’s objective is to present a methodology and to provide suggestions to the engineering community and protection agencies such as FEMA and the U.S. Army Corps of Engineers (USACE) about a method to lessen damage to groups of manufactured homes. To support the development of this methodology with analysis, an unsteady, Reynolds-averaged, Navier-Stokes computational tool was employed to model a manufactured-home park to evaluate how well a wind barrier installed along its upwind periphery could establish skimming flow over all the buildings in the park. A manufactured-home park that had existed in Punta Gorda, Florida, was studied because satellite pictures before and after it was heavily damaged by Hurricane Charley on August 13, 2004, were available. Computations were performed using a computer program and the $k-\omega$ shear-stress transport model with enhanced wall treatment to capture most of the flow features near the barrier and building walls. A 3.05-m high barrier slanted downwind at 45° to the horizontal was placed along the southern and western sides of the park at spacing-to-building height ($b/h$) ratios of 0.1, 0.5, and 1.0. Comparisons with the no-barrier case were made using the pressure coefficient and wind speed. Both were considerably reduced throughout the park by the barrier. Pertinent concluding remarks and suggestions to the engineering community are presented.

This paper proposes a robust adaptive strategy for longitudinal dynamics of generic hypersonic flight vehicles with uncertainties and faults. Flight vehicles are generally subjected to disturbances and multiple faults, which should be compensated for to preclude performance degradation. To solve this problem, considering fast abrupt faults such as actuator stuck faults, an adaptive fault observer is added into the nominal dynamic inversion controller to accommodate the effects of faults with discrete function patterns. In addition, since the above observer is designed only for fast abrupt faults, an online support vector machine compensator is proposed to learn the state error caused by other faults. As the error contains both dynamic uncertainties and slow variation faults, additional controllers are not required to get rid of the unwanted faults. Stability of the overall closed-loop system is analyzed with the Lyapunov stability theory, and output tracks the expected trajectory. The simulation is presented with multiple faults to verify the effectiveness and feasibility of the proposed scheme.

For the combustion research of boron particles in solid rocket ramjets, a new experimental system has been developed, which can be used to mimic the flow field conditions in solid rocket ramjets with high temperature, pressure, and convection. The combustion processes in the afterburning section were recorded by a high-speed photography system through two quartz windows. Sampling devices have been designed and used to collect solid combustion products during tests. The scanning electron microscope (SEM) photographs of the collected solid products show that agglomeration was formed while boron particles were heated and combusted. With the X-ray diffraction (XRD) and electron diffraction spectra (EDS) results, reaction rate and complete reaction rate of boron have been defined and investigated at different points in the experimental system. It was concluded that the value of boron reaction rate is the lowest in the region around the air entrances and the highest in the next region downstream. The complete reaction rate of boron, which was defined as the proportion of the mass of boron oxidized to ${\mathrm{B}}_2{\mathrm{O}}_3$ to the mass of boron combusted, revealed that only a part of the consumed boron was oxidized to ${\mathrm{B}}_2{\mathrm{O}}_3$. However, the value of the complete reaction rate changed little in the whole experimental system. Some suggestions for optimizing afterburner structure to get high boron reaction rate and high potential energy release have been given.

By introducing thermal expansion coefficients in the transverse displacement field, this paper proposes an approach to improve the performance of the global-local higher-order theory for thermal stress analysis of laminated composite plates. Transverse normal deformation has been considered in the proposed model, whereas the additional displacement variables have not increased because thermal loads could be included in the generalized force vector. The proposed model a priori satisfies the continuity conditions of transverse shear stresses at interfaces, and the number of displacement variables involved in the present model is independent of the number of layers. The derivatives of transverse displacement have been eliminated from the displacement field so that the $C^0$ interpolation functions are only required for the finite-element implementation. Based on the proposed model, a six-node triangular element is proposed for thermal expansion problems of laminated composite and sandwich plates. Numerical results show that the proposed model can produce a more accurate response of laminated composite plates under temperature loads than other models.

The exploration and development of space will require energy that is reliable, ubiquitous, and economical to produce. The international space station relies on photovoltaics to generate electricity stored in nickel-hydrogen batteries for powering the station during the “night”. This paper investigates an alternative technology designed to take advantage of in-situ resource utilization (ISRU) available on the moon or other celestial bodies. Rather than depending on chemical batteries to store energy the envisioned method would “stock” solar thermal energy in sintered regolith, serving as a thermal battery that provides heat and power during the long night. It discusses the sintering process and the temperatures required to achieve agglomeration of the Australian Lunar Regolith Simulant-1 (ALRS-1). The main aim of the presented work was to determine the specific heat capacity of a sintered simulant, across a temperature range of 25°C to 700°C. Discussed are the concept of a closed cycle power storage system as well as methods and equipment employed for the experimental work. While the conducted tests are exploratory in nature, the first results encourage further work.

This paper addresses the command tracking control system (CTCS) design problem for plants involving input quantization and input saturation. A novel approach is proposed and demonstrated to the angle of attack (AOA) CTCS and bank angle CTCS of hypersonic reentry vehicles (HRV) driven by a reaction control system (RCS). First, the six-degree-of-freedom (6-DOF) nonlinear dynamic model of HRV and the mathematical model of RCS are established, and dynamic analysis is conducted based on the linearized model of HRV. Second, a general CTCS for plants involving input quantization and saturation is designed by solving a convex optimization problem based on linear matrix inequalities (LMIs). Formulations of the domains of attraction and convergence of the closed loop CTCS are derived. Furthermore, input to state stability (ISS) of the closed loop system is analyzed. Finally, the proposed approach is applied to design the longitudinal AOA CTCS and lateral–directional bank angle CTCS of HRV driven by an RCS. Validation simulations are conducted by using the linear model and the 6-DOF nonlinear dynamic model of HRV, which indicate that the proposed LMIs based approach is well suited for CTCS design for static–unstable plants and multiaxis coupling plants driven by actuators with quantization and saturation.

This paper studies maneuver estimation of the controllable-structure semiballistic reentry vehicle (SBRV) by the multiple-model approach. Three kinds of small cardinality model sets are developed to match the vehicle’s uncertain maneuvers: the minimum model set from a new rule for three-dimensional maneuvers, its projection in the mode space’s subspace for two-dimensional maneuvers, and their modifications. Based on these model sets, the multiple-model SBRV tracking estimator is designed to track the vehicle. Simulation results on the vehicle’s random maneuvering demonstrate that the credibility, estimation errors, and sensitivity of the estimators based on the newly designed model set have been improved.