This article investigates the trade-off among average uplink rate, propulsion energy consumption, and sensor energy efficiency in multi-unmanned aerial vehicle (UAV) data collection systems, with a particular focus on obstacle avoidance and collision prevention. A constrained multi-variable optimization problem is formulated, incorporating real-time constraints such as sensor upload rates, obstacle avoidance, and collision-free trajectory requirements. To solve this, a two-layer optimization framework is proposed, integrating block coordinate descent (BCD) and serial coordination to decompose the problem into tractable subproblems: sensor scheduling, power allocation, and trajectory planning. Notably, a penalty-based successive convex approximation (SCA) method is employed to enforce collision-free constraints during trajectory optimization, ensuring safe in cluttered environments. Simulation results demonstrate that adjusting weight parameters allows the algorithm to dynamically prioritize cost-benefit trade-offs while robustly maintaining obstacle avoidance and collision prevention, even in scalable multi-UAV scenarios.

This work investigates the spall damage and microstructural deformation behaviors of a heat-treated, hierarchical structured 18 wt% Ni-350 maraging steel (M350) produced by laser powder bed fusion (LPBF) under shock loading. The samples were shock-loaded along different orientations with peak shock stresses ranging from 7.0 GPa to 10.5 GPa. Experimental results demonstrate that the M350 exhibits ultra-high spall strength of 5.01-5.89 GPa and 4.53-4.99 GPa when loading perpendicularly and parallel to the building direction, respectively. Spall damage is characterized as a typical transgranular brittle fracture with {100} cleavage planes within the block. The observed superior mechanical performance is attributed to the precipitation strengthening and the transformation-induced plasticity (TRIP) effect. Dislocation slip cuts through the Ni3Ti precipitates, causing them to fracture, simultaneously, high density precipitates impede dislocation movement according to the Orowan mechanism, preventing the formation of microcracks. The residual austenite undergoes martensitic transformation with the formation of new secondary laths with widths of 20-60 nm to accommodate localized plastic deformations, which creates a large number of grain boundaries and leads to grain refinement.

Tailless unmanned aerial vehicles (UAVs) achieve high-agility maneuvers with flight control systems. The attainable moment set (AMS) provides critical theoretical foundations and constraints for their optimization. A computational method is proposed herein to address controllability limitations caused by nonlinear aerodynamic effectiveness. This method incorporates dual constraints on control surface angles and angular rates for the nonlinear AMS, aiming to meet the demands of attitude tracking dynamics in flight control systems. First, a quantitative model is established to correlate dual deflection constraints with aerodynamic moment amplitude and bandwidth limitations. Next, we construct a computational framework for the incremental attainable moment set (IAMS) based on differential inclusion theory. For monotonic nonlinear aerodynamic effectiveness, the vertices of the IAMS are updated using local interpolation, yielding the incremental nonlinear attainable moment set (INAMS). When non-monotonic nonlinearity occurs, stationary points are calculated to adjust the control effectiveness matrix and admissible control set, thereby reducing computational errors induced by non-monotonic characteristics. Furthermore, the effective actions set, derived from a time-varying incremental nonlinear attainable moment set, quantifies the residual moment envelope of tailless UAVs during maneuvers. Comparative simulations indicate that the proposed method achieves correct computation under nonlinear aerodynamic conditions while reliably determining safe flight boundaries during control failure.

The strain rate dependence of mechanical behavior in an AlSi10Mg alloy with different states fabricated by laser powder bed fusion (LPBF) was investigated systematically via thermodynamic calculations, microstructure characterization and mechanical characteristic evaluation in the present study. The results show that there is a close relationship among the material state, microstructure and dynamic mechanical behavior. Before tensile deformation, the as-built specimen possesses a fine equiaxed grain structure and a typical cellular structure surrounded by continuously distributed particles; the annealed specimen has coarser equiaxed grain structures and particles, but no cellular structure is present. Both the as-built and annealed specimens exhibit weak strain rate sensitivity, and the strain rate sensitivity parameters are 0.01 and 0.024, respectively. Under specific strain rate conditions, the as-built specimen has a higher strength and lower elongation than the annealed specimen. After tensile deformation, there is a significant increase in the dislocation density. Independent of the material state, the dislocation density increases with increasing strain rate. Compared with the as-built specimen, the annealed specimen has a stronger strain rate sensitivity because of the greater dislocation density variation.

The spall response and microstructure evolution of additively manufactured AlSi10Mg alloy with different states were investigated systematically through plate impact experiments, microstructure and texture characterization and quasi-static tensile tests. The results show that the microstructure, texture and spall response are related to the impact velocity and material state. Before deformation and fracture failure occur, the as-built and annealed specimens possess the same <001> texture along the building direction; the former consists of numerous networks, columnar grains and fine equiaxed grains, and the latter is comprised of coarser grain structure and coarse particles. For both the as-built and annealed specimens, as the impact velocity increases, the Hugoniot elastic limit (HEL) stress and spall strength are slightly affected by the impact velocity; however, the peak shock stress tends to increase. Under the same impact velocity conditions, compared with the as-built specimen, the annealed specimen corresponds to a similar peak shock stress but a lower Hugoniot elastic limit stress and spall strength. Independent of the material state, as the impact velocity increases, the damage gradually increases, namely, from incipient spall to complete spall; the grain structure, including size and shape changes; and the texture remains almost unchanged. Under the same impact velocity conditions, compared with the as-built specimen, the annealed specimen has a coarser grain structure and a similar texture. Voids tend to nucleate at grain boundaries (at the bottom of the melt pool) and large particles. Compared with the as-built specimen, the annealed specimen has greater strain rate sensitivity. The effect of the material state on the tensile strength is dependent on the strain rate, and the annealing treatment may significantly decrease the tensile strength under low strain rate conditions; and weakly decrease it under high strain rate conditions. Finally, the spall strength dependence on the material state and the effect of the strain rate on the spall behavior were discussed.

This letter presents a new approach to enhance the anti-jamming capability of unmanned aerial vehicle (UAV)-assisted wireless data collection, specifically addressing the challenge of multi-jammers attacks in the context of imperfect channel state information (CSI). The proposed approach is designed for a scenario where a single UAV is responsible for collecting data from multiple ground sensors, while encountering multi-jammers from a ground-based adversary. The objective is to maximize the average data rate of all sensors while ensuring a sufficient amount of data is collected from each sensor. The optimization problem is formulated as a mixed-integer non-convex problem, and successive convex approximation(SCA) technique is employed, which jointly optimizes the collection schedule, power control and UAV trajectory. Numerical simulations demonstrate that the proposed approach outperforms in the presence of interference and imperfect CSI.

The mechanical behaviors and microstructure evolutions of different aluminum materials including high-purity aluminum, 7075 aluminum alloy and selective laser melted (SLM) AlSi10Mg alloy under shock loading were investigated through plate impact experiments and microstructure characterization. The results show that the Hugoniot elastic limit stress has nothing to do with impact velocity, but is related to material type; the peak shock stress significantly increases with increasing impact velocity and is somewhat affected by material type. The microstructure variation is highly dependent on the material type. In the 7075 aluminum alloy and selectively laser melted (SLM) AlSi10Mg alloy with relatively high strengths, the microstructure, including the grain size, grain shape and misorientation angle, is slightly influenced by the impact velocity. In high-purity aluminum with low strength, the microstructure is closely related to the impact velocity. As the impact velocity increases, dislocations, elongated subgrains, equiaxed subgrains and a fraction of low angle grain boundaries (LAGBs) first increase and then decrease, accompanied by the formation of numerous ultrafine equiaxed grains with sizes in the range of 1–5 μm. The limited adiabatic temperature rise during high-velocity impact cannot affect the microstructure. High rate loading was confirmed as an effective and promising method to refine grain structure for low strength materials.

This work investigates the pseudo-command restricted problem for tailless unmanned aerial vehicles with snake-shaped maneuver flight missions. The main challenge of designing such a pseudo-command restricted controller lies in the fact that the necessity of control allocation means it will be difficult to provide a precise envelope of pseudo-command to the flight controller; designing a compensation system to deal with insufficient capabilities beyond this envelope is another challenge. The envelope of pseudo-command can be expressed by attainable moment sets, which leave some open problems, such as how to obtain the attainable moment sets online and how to reduce the computational complexity of the algorithm, as well as how to ensure independent control allocation and the convexity of attainable moments sets. In this article, an innovative algorithm is proposed for the calculation of attainable moment sets, which can be implemented by fitting wind tunnel data into a function to solve the problems presented above. Furthermore, the algorithm is independent of control allocation and can be obtained online. Moreover, based on the above attainable moment sets algorithm, a flight performance assurance system is designed, which not only guarantees that the command is constrained within the envelope so that its behavior is more predictable, but also supports adaptive compensation for the pseudo-command restricted controller. Finally, the effectiveness of the AMS algorithm and the advantages of the pseudo-command restricted control system are validated through two sets of independent simulations.

Supersonic Tailless Aerial Vehicles (STAVs) will become an essential force in Penetrating Counter Air (PCA), but STAVs do not have the traditional horizontal and vertical tails, making pitch and yaw control difficult. The attack angle and the sideslip angle need to be limited to ensure that the engine inlet and the aerodynamic rudder at the rear of the vehicle can work properly, which is the so-called security constraints. In addition, the tracking error of the aerodynamic angle needs to be limited to achieve effective attitude control or high-accuracy tracking of trajectories, which is the so-called performance constraints. To this end, an attitude control method that meets the needs of PCA has been devised, based on constraint definition, coupled constraints handling, and control law design. Firstly, mathematical descriptions of the security constraints, performance constraints, and control constraints are given. Secondly, two treatment methods, coupled command filter and coupled funnel control are proposed for the aerodynamic angle coupled constraint problem. Finally, based on Nonlinear Dynamic Inverse (NDI) design, the coupled funnel controller is designed and validated by simulation for two typical mission scenarios, high-altitude penetration and low-altitude surprise defence. The proposed control method not only satisfies the security and performance constraints of STAV attitude control but also is highly robust.

In order to elucidate the constraints of autonomy, this article starts from the definition of boundaries and speculates on the autonomy of unmanned systems based on performance constraints. Furthermore, it combines with the OODA loop to explain the hardware and software constraints of autonomy throughout the entire process of perception, planning, decision-making, and control from a system perspective. Finally, through three autonomy tasks, including control allocation, flight control, and path planning, it specifically illustrates the impact of basic capabilities of unmanned platforms, artificial intelligence capabilities, and safety constraints on autonomy. The results indicate that autonomy can only be effective within certain constraints, and once these constraints are exceeded, autonomy becomes difficult to achieve. This suggests that when studying autonomy problems, the practical significance of autonomy should be considered based on the performance constraints of the system, and optimization methods should be employed to find solutions to access the feasibility of autonomy.

Using adaptive dynamic programming (ADP), this paper presents a novel attitude-tracking scheme for over-actuated tailless unmanned aerial vehicles (UAVs) that integrates control and control allocation while accounting for nonlinearity and nonaffine control inputs. The proposed method uses the idea of nonlinear dynamic inversion to create an augmented system and converts the optimal tracking problem into an optimal regulation problem using a discounted performance function. Drawing inspiration from incremental control, this method achieves optimal tracking control for the nonaffine system by simply using a critic-only structure. Moreover, the unique design of the performance function ensures robustness against model uncertainties and external disturbances. The ADP method was found to outperform traditional control architectures that separate control and control allocation, achieving the same level of attitude-tracking performance through a more optimized approach. Furthermore, unlike many recent optimal controllers for nonaffine systems, our method does not require any model identifiers and demonstrates robustness. The superiority of the ADP-based approach is verified through two simulated scenarios, and its internal mechanism is further discussed. The theoretical analysis of robustness and stability is also provided.

Shape memory alloys are emerging functional materials in various fields due to their unique mechanical properties. In this work, plate-impact experiments have been performed to study the dynamic behavior of near-equiatomic NiTi shape memory alloys with different initial phases, i.e., the single austenite (B2) and the mixed phase of austenite and martensite (B19 & PRIME;). A Doppler pin system and soft-recovery cylinder are employed to in-situ probe the macroscopic response and catch the shocked sample for postmortem characterizations, respectively. The observed bilinear behavior of the Hugoniot data, combined with the X-ray diffraction analysis of recovered samples, suggests that the B2 austenite undergoes a martensitic transformation at-5 GPa. Such a phase transition affects not only the spall damage but also the deformation mechanism of NiTi alloys. Specifically, it is identified that, in association with the B2 to B19' transformation, the spall strength is reduced by-7% and the austenite twinning disappears in the recovered NiTi sample. These results thus indicate that the deformation and fracture behaviors of NiTi shape memory alloys under shock compression are strongly coupled with the martensitic transformation.

The slow convergence rate and large cost of the initial solution limit the performance of rapidly exploring random tree star (RRT*). To address this issue, this paper proposes a modified RRT* algorithm (defined as FF-RRT*) that creates an optimal initial solution with a fast convergence rate. An improved hybrid sampling method is proposed to speed up the convergence rate by decreasing the iterations and overcoming the application limitation of the original hybrid sampling method towards concave cavity obstacle. The improved hybrid sampling method combines the goal bias sampling strategy and random sampling strategy, which requires a few searching time, resulting in a faster convergence rate than the existing method. Then, a parent node is created for the sampling node to optimize the path. Finally, the performance of FF-RRT* is validated in four simulation environments and compared with the other algorithms. The FF-RRT* shortens 32% of the convergence time in complex maze environment and 25% of the convergence time in simple maze environment compared to F-RRT*. And in a complex maze with a concave cavity obstacle, the average convergence time of Fast-RRT* in this environment is 134% more than the complex maze environment compared to 12% with F-RRT* and 34% with FF-RRT*. The simulation results show that FF-RRT* possesses superior performance compared to the other algorithms, and also fits with a much more complex environment.

To address the faults of the tailless aerial vehicle control surface with nonlinear control effectiveness, a reconfiguration incremental control allocation method is proposed. Under the framework of incremental control allocation, four types of typical control surface faults, such as floating, jamming, damaged, and median offset, are modeled. The isolation of faulty control surfaces and the reconfiguration of the flight control system is realized by adjusting the control surface deflection increment limit and changing the local control effectiveness matrix. The results show that the method can effectively take advantage of the redundant configuration of the control surface, prevent the system from losing control caused by the fault of the control surface, and enhance the safety and reliability of the system.

针对超声速无尾飞行器操纵面冗余度高、舵效非线性强、超声速巡航阻力大的问题,提出了一种最小阻力增量控制分配方法.在增量非线性控制分配框架下对超声速无尾飞行器的控制分配问题进行重构,然后在操纵面幅值与速率约束下,构建增量形式"分配精度-阻力"混合优化目标,并使用有效集二次规划求解,形成了一套完整的最小阻力控制分配方法.在超声速巡航条件下进行仿真,结果表明该方法可有效分配虚拟控制指令,减小飞行阻力.

This paper explores the joint cache placement and 3D deployment of Unmanned Aerial Vehicle (UAV) groups, utilizing potential game theory and a two-hop UAV cooperative caching mechanism, which could create a tradeoff between latency and coverage. The proposed scheme consists of three parts: first, the initial 2D location of UAV groups is determined through K-means, with the optimal altitude based on the UAV coverage radius. Second, to balance the transmission delay and coverage, the MOS (Mean Opinion Score) and coverage are designed to evaluate the performance of UAV-assisted networks. Then, the potential game is modeled, which transfers the optimization problem into the maximization of the whole network utility. The locally coupling effect resulting from action changes among UAVs is considered in the design of the potential game utility function. Moreover, a log-linear learning scheme is applied to solve the problem. Finally, the simulation results verify the superiority of the proposed scheme in terms of the achievable transmission delay and coverage performance compared with two other tested schemes. The coverage ratio is close to 100% when the UAV number is 25, and the user number is 150; in addition, this game outperforms the benchmarks when it comes to maximizing MOS of users.

Physisorption relying on crystalline porous materials offers prospective avenues for sustainable separation processes, greenhouse gas capture, and energy storage. However, the lack of end-to-end deep learning model for adsorption prediction confines the rapid and precise screen of crystalline porous materials. Here, we present DeepSorption, a spatial atom interaction learning network that realizes accurate, fast, and direct structure-adsorption prediction with only information of atomic coordinate and chemical element types. The breakthrough in prediction is attributed to the awareness of global structure and local spatial atom interactions endowed by the developed Matformer, which provides the intuitive visualization of atomic-level thinking and executing trajectory in crystalline porous materials prediction. Complete adsorption curves prediction could be performed using DeepSorption with a higher accuracy than Grand canonical Monte Carlo simulation and other machine learning models, a 20-35% decline in the mean absolute error compared to graph neural network CGCNN and machine learning models based on descriptors. Since the established direct associations between raw structure and target functions are based on the understanding of the fundamental chemistry of interatomic interactions, the deep learning network is rationally universal in predicting the different physicochemical properties of various crystalline materials.

This paper presents a fault-tolerant attitude control scheme, incorporating reconfiguration control allocation for supersonic tailless aircraft subject to nonlinear characteristics, actuator constraint, uncertainty, and actuator faults. The main idea is to propose an incremental reconfiguration closed-loop control allocation scheme, coupled with a basic backstepping attitude controller, to achieve attitude control. Based on the virtual control input generated by the basic backstepping attitude controller, firstly, the incremental nonlinear control allocation method is adopted to deal with the nonlinear characteristics and actuator constraint. Secondly, a distribution error feedback loop is constructed in the incremental nonlinear control allocation method to enhance the robustness against the uncertainty of the control effectiveness matrix. Thirdly, the control effectiveness matrix is reconstructed by different kinds of fault information to deal with actuator faults, and the proper combination of actuator deflections is generated to achieve accurate command tracking. The stability of the proposed scheme is guaranteed by the Jury stability criterion and the Lyapunov stability analysis. Finally, in comparison with the three existing approaches, the simulation results of two cases are provided to show the effectiveness of the proposed scheme.

Abstract Purpose Paliperidone is an atypical antipsychotic as effective as other atypical antipsychotics for schizophrenia. However, few studies have explored the efficacy of paliperidone for treatment-resistant schizophrenia. This study aimed to compare the efficacy and safety of paliperidone extended release (ER) versus olanzapine in schizophrenia patients with either poor treatment response or intolerable adverse effects due to standardized antipsychotic therapy. Methods This 12-week randomized, double-blind, multicenter study compared the treatment efficacy on psychotic symptoms, cognitive functions, and tolerance between paliperidone ER (6–15 mg/d, n = 45) and olanzapine (10–30 mg/d, n = 41) in treatment-resistant or treatment-intolerant patients with schizophrenia. The severity of psychotic symptoms was evaluated by the Positive and Negative Syndrome Scale and the Clinical Global Impression Severity of Illness Scale. The cognitive functions were assessed by the MATRICS Consensus Cognitive Battery. In addition, the metabolic impacts were evaluated by weight gain and waist circumference. Results Patients with either paliperidone ER or olanzapine treatment showed apparent improvement in psychotic symptoms, without significant intergroup difference. Twelve-week paliperidone ER or olanzapine treatment did not improve the cognitive functions. Both paliperidone ER and olanzapine treatment caused significant increase in weight and waist circumference, and olanzapine had a greater impact on waist circumference than paliperidone ER. In addition, both drugs were well tolerated. Conclusions Paliperidone ER could be a safe alternative for treatment-resistant schizophrenia.