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The parafoil is highly susceptible to deviations from its reference trajectory under wind disturbances. Given its constrained longitudinal control authority, it has limited capability to correct these deviations and regain the intended glide path. To overcome this limitation, we propose a dynamic planning framework based on a layered homing strategy. The airdrop mission trajectory is initially designed as a traditional multi-segment path. To approximate non-uniform glide characteristics under wind disturbances, this planning problem incorporates a predicted wind model as an external input. Node parameters of the segmented trajectory are then solved using an improved grey wolf optimizer (IGWO). By tracking this reference trajectory, the parafoil is guided into the proximity of the target. To ensure landing precision, the terminal phase is formulated and discretized using an adaptive pseudo-spectral method (APSM). The online planner computes a real-time trajectory to account for actual motion characteristics. This dynamic replanning (DRP) compensates for deviations caused by model mismatches and external disturbances. The proposed homing method is statistically verified via extensive Monte Carlo simulations under different wind conditions. Finally, the airdrop experiment is conducted to validate the DRP method.

Tiltrotor aircrafts have both fixed-wing control surfaces and helicopter rotors for attitude control. The redundancy of control surfaces provides the possibility for the control system to reconfigure the control law when actuator faults occur during flight. Possible actuator faults have been classified into two categories: predictable and unpredictable faults, and a different strategy has been adopted to deal with each kind of fault. Firstly, the predictable faults are handled by a multiple-model switching adaptive scheme. These kinds of faults are modeled, and their corresponding controllers are derived offline. Secondly, since the degree of drop in aerodynamic effectiveness cannot be predicted a priori, unpredictable faults are handled by a simple adaptive control scheme, to force the plant with faults to track the prescribed reference model. The presented methodology has been verified by nonlinear full-envelope flight simulation for both categories of actuator faults. The predictable fault is represented by the elevator floating. Elevator damage causing an aerodynamic effectiveness drop by 80% is chosen as the example of unpredictable fault. Both faults are simulated at the late stage of the tiltrotor conversion mode. Results show that the presented strategy of reconfiguration is able to detect the fault rapidly and stabilize the aircraft when a fault occurs, while the aircraft motion diverges without the reconfiguration scheme. The aircraft also presents a relatively good performance under controller reconfiguration with a well-tracked conversion path.

This work presents a systematic approach to analyzing the aerodynamic characteristics of tandem rotor forward autorotation considering rotor-to-rotor interference. The single-rotor computational model trimmed from a generic helicopter flight dynamics analysis program was used as the baseline model. The effectiveness of the baseline model is demonstrated by a comparison with data from wind tunnel tests performed in this work. The rotor disk angle of attack and driven moment distribution obtained by the modified model indicate the fact that the rotor acceleration is primarily caused by the higher angle of attack region of the disk. This is of great significance in the rotor blade design, in terms of the drag-to-lift ratio characteristics of the airfoil under different angle-of-attack ranges. The influence of wind speed, rotor shaft angle, and collective pitch on the steady-state rotor speed was then studied. The results show a nonlinear nature of the variation of steady rotor speed with collective pitch, which can cause a thrust control reverse problem during flight operations. To reveal the flow field details of rotor-to-rotor interference, the flow field Navier–Stokes equations of tandem rotor autorotation were solved. Computational results of both rotors’ inflow velocities were considered when deriving the empirical model of interference. The refined interference model was compared to the wind tunnel test data of the tandem rotor autorotation and showed good performance. This synthetical methodology, which combines mechanism analysis with CFD-aided refinement and experiment verification, achieves a balance between computational costs and accuracy and thus can be readily applied to engineering practices.

Neural networks have been widely used as compensational models for aircraft control designs and as surrogate models for other optimizations. In the case of tiltrotor aircraft, the total number of aircraft states and controls is much greater than that of both traditional fixed-wings and helicopters. This requires, in general, a huge amount of training data for the network to reach a satisfactory approximation precision and makes the network size rise considerably. To solve the practical problem of reducing the size of the approximating network, efforts have to be made in the efficient utilization of the limited amount of training data. This work presents the methodology of optimizing the sample pattern of the training data set by adopting the metaheuristic algorithm of the particle swarm optimizer improved by the fourth-order Runge–Kutta algorithm. A 6-degree-of-freedom nonlinear flight dynamics model of the tiltrotor aircraft is derived, along with its approximation radial basis function neural network. An example case of approximating a highly nonlinear function is studied to illustrate the principle and main parameters of the optimizer, and the approximation performance of the time-domain response of the unstable nonlinear system is revealed by the study of a Van der Pol oscillator. Then, the presented method is applied to the modeled tiltrotor aircraft for its early and late conversion modes. The optimization scheme shows great improvement in both cases, as the function approximation error is reduced significantly.

The Lie symmetry analysis is adopted to the (2 + 1)-dimensional dispersionless B-type Kadomtsev–Petviashvili (dBKP) equation. The combination of symmetry analysis and symbolic computing methods proves that Lie algebra of infinitesimal symmetry of the dBKP equation depends on four independent arbitrary functions and one arbitrary parameter. The Lie algebra is reduced to four classes for deriving commutative relations, group invariant solutions of dBKP equation and conservation laws, and the optimal system of 1-dimensional subalgebras from one class is constructed. Based on the optimal system and other particular infinitesimal symmetries, plentiful symmetry reductions and invariant solutions are computed by using Lie group method. Six successive symmetries and conserved quantities of the dBKP equation are linked by the new conservation theorem. Besides, exact solution of the dBKP equation is constructed according to a conservation vector.

Symmetry, which describes invariance, is an eternal concern in mathematics and physics, especially in the investigation of solutions to the partial differential equation (PDE). A PDE's nonlocally related PDE systems provide excellent approaches to search for various symmetries that expand the range of its known solutions. They composed of potential systems based on conservation laws and inverse potential systems (IPS) based on differential invariants. Our study is devoted to generalizing their construction and application in three-dimensional circumstances. Concretely, the potential of the algebraic gauge-constrained potential system is simplified without weakening its solution space. The potential system is extended via nonlocal conservation laws and double reductions. Afterwards, nonlocal symmetries are identified in the IPS.\\@ The IPS is extended by the solvable Lie algebra and type 2 hidden symmetries. Besides, systems among equations can be connected via Cole-Hopf transformation.\\@ Ultimately, established and extended systems embody rich symmetric properties and unprecedented analytical solutions, and may even further facilitate general coordinate-independent analysis in qualitative, numerical, perturbation, etc., this can be illustrated by several Burgers-type equations.

Symmetry, which describes invariance, is an eternal concern in mathematics and physics, especially in the investigation of solutions to the partial differential equation (PDE). A PDE's nonlocally related PDE systems provide excellent approaches to search for various symmetries that expand the range of its known solutions. They composed of potential systems based on conservation laws and inverse potential systems (IPS) based on differential invariants. Our study is devoted to generalizing their construction and application in three-dimensional circumstances. Concretely, the potential of the algebraic gauge-constrained potential system is simplified without weakening its solution space. The potential system is extended via nonlocal conservation laws and double reductions. Afterwards, nonlocal symmetries are identified in the IPS.\\@ The IPS is extended by the solvable Lie algebra and type 2 hidden symmetries. Besides, systems among equations can be connected via Cole-Hopf transformation.\\@ Ultimately, established and extended systems embody rich symmetric properties and unprecedented analytical solutions, and may even further facilitate general coordinate-independent analysis in qualitative, numerical, perturbation, etc., this can be illustrated by several Burgers-type equations.

A remote AMR system based on a STC90C52AD microcontroller and wireless network technology is presented in this paper to solve the problems in existing AMR system. Based on Smart Home system with grid demand side energy management, the automatic meter reading system centralizes electric power, water, gas meters, provides remote real-time automatic meter reading services and give instruction suggestions which contribute to energy management. Through the Web application platform, the users can use the Internet, mobile phones and other means to achieve the remote monitoring of the household appliances, energy-saving and saving house electricity costs. This AMR system has been implemented successfully by the State Grid Corporation Shandong Electric Power Group Corporation and the department of Automation of Wuhan University in collaboration.

A remote indoor environment monitoring system based on a STC90C52AD microcontroller and wireless network technology is presented in this paper to solve the problems in existing environment monitoring system. With a Web control platform, the environmental monitoring systems can remotely monitor the indoor environment, and scientifically guide users to improve the indoor environment. The environmental monitoring module is communicated with display terminal, so that users can use PC, mobile phone or Pad to achieve the remote monitoring for indoor environmental via the Internet, GPRS, 3G and other networks. To improve the quality of life while achieve intelligent management. This system has been implemented successfully by the State Grid Corporation Shandong Electric Power Group Corporation and the department of Automation of Wuhan University in collaboration.

Immunotherapy with immune checkpoint inhibitors had achieved great success. However, only a subset of patients responds positively to these therapies. The latest study published on Nature by Chou and colleagues found a new T cell subset from tumor-infiltrating T cells which lack PD-1 on the cell surface and potent cytotoxic activities against tumor cells. This finding provides a novel insight into the development of new therapies for tumors that do not respond to immune checkpoint blockade in the future.