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Addressing input saturation, external disturbances, and uncertain system parameters, this paper investigates the position tracking control problem for bilateral teleoperation systems with a time delay communication channel. Based on a composite energy function, we propose an adaptive iterative learning control (AILC) method to achieve the objective of position tracking under the alignment condition. This extends the existing research on the control of nonlinear teleoperation systems with time delay. The saturation constraint property of the Softsign function ensures that no state of the system exceeds its constraints. The controller learns to simultaneously deal with the uncertainty of system parameters online, reject external disturbances, and eliminate positional errors along the time and iteration axes. All signals in the system for any constant time delay are proved to be bounded. Ultimately, the performance of the proposed controller is further verified through numerical simulations. [ABSTRACT FROM AUTHOR]

In order to solve the problem of variable steady-state operation nodes and poor coordination control effect in photovoltaic energy storage plants, the coordination control strategy of photovoltaic energy storage plants based on ADP is studied. Establish the photovoltaic energy storage power station model including photovoltaic system model, super capacitor system model and battery system model; Set the maximum limit of active power change as the power constraint condition for coordinated control of photovoltaic energy storage station; The optimal control problem of multi voltage and reactive power resource coordination is fully considered, the optimal voltage control model is established by using ADP algorithm, and the optimal coordinated control strategy is obtained by online learning the collected dynamic operation information. The experimental results show that this strategy can improve the coordinated control effect of the photovoltaic energy storage station, ensure the photovoltaic energy storage station in a stable operation state, improve the service life of the energy storage device in the photovoltaic energy storage station, and stabilize the steady-state operating node voltage within the ideal fluctuation range. [ABSTRACT FROM AUTHOR]

To address the high complexity and low accuracy issues of traditional methods in mixed coal vitrinite identification, this paper proposes a method based on an improved DeepLabv3+ network. First, MobileNetV2 is used as the backbone network to reduce the number of parameters. Second, an atrous convolution layer with a dilation rate of 24 is added to the ASPP (atrous spatial pyramid pooling) module to further increase the receptive field. Meanwhile, a CBAM (convolutional block attention module) attention mechanism with a channel multiplier of 8 is introduced at the output part of the ASPP module to better filter out important semantic features. Then, a corrective convolution module is added to the network's output to ensure the consistency of each channel's output feature map for each type of vitrinite. Finally, images of 14 single vitrinite components are used as training samples for network training, and a validation set is used for identification testing. The results show that the improved DeepLabv3+ achieves 6.14% and 3.68% improvements in MIOU (mean intersection over union) and MPA (mean pixel accuracy), respectively, compared to the original DeepLabv3+; 12% and 5.3% improvements compared to U-Net; 9.26% and 4.73% improvements compared to PSPNet with ResNet as the backbone; 5.4% and 9.34% improvements compared to PSPNet with MobileNetV2 as the backbone; and 6.46% and 9.05% improvements compared to HRNet. Additionally, the improved ASPP module increases MIOU and MPA by 3.23% and 1.93%, respectively, compared to the original module. The CBAM attention mechanism with a channel multiplier of 8 improves MIOU and MPA by 1.97% and 1.72%, respectively, compared to the original channel multiplier of 16. The data indicate that the proposed identification method significantly improves recognition accuracy and can be effectively applied to mixed coal vitrinite identification. [ABSTRACT FROM AUTHOR]

Aiming to address the A* algorithm's issues of traversing a large number of nodes, long search times, and large turning angles in path planning, a strategy for multiple improvements to the A* algorithm is proposed. Firstly, the calculation of the heuristic function is refined by utilizing the Octile distance instead of traditional distance, which more accurately predicts the optimal path length. Additionally, environmental constraints are introduced to adaptively adjust the weight of the heuristic function, balancing the trade-off between search speed and path length. Secondly, the bidirectional jump point search method is integrated, allowing simultaneous path searches from both directions. This significantly reduces path search times and the number of nodes traversed. Finally, the path undergoes two rounds of smoothing using a path smoothing strategy until the final path is generated. To validate the effectiveness of the improved A* algorithm, simulations are conducted on ten types of grid maps. Results demonstrate that the improved A* algorithm markedly decreases path search times while maintaining path length, with greater speed improvements observed as the map size increases. Furthermore, the improved algorithm is applied in experiments with mobile robots, achieving significant reductions in average path search times of 79.04% and 37.41% compared to the traditional A* algorithm and the JPS algorithm, respectively. This enhancement effectively meets the requirements for rapid path planning in mobile robotics applications. [ABSTRACT FROM AUTHOR]

The sleeve grouting connection is the most common form of vertical connection for prefabricated shear walls. However, during construction, this type of connection is prone to defects such as insufficient anchorage length of reinforcement, deviation of reinforcement, and insufficient amount of sleeve grouting, which significantly impact the integrity and seismic performance of the prefabricated shear wall structure. The finite element analysis of the prefabricated shear wall with sleeve grouting connection is still based on solid element modeling. This method has the disadvantages of complex models and low computational efficiency. In this paper, a simplified modeling method for prefabricated shear walls considering sleeve grouting defects was proposed to address this issue. Firstly, the equivalent constitutive relationship of the sleeve grouting defect connector was constructed based on the uniaxial tensile test of the existing sleeve grouting defect connector, and the T3D2 element was used to simulate the sleeve grouting connector. Then, the mechanical behavior of the horizontal joint between the shear wall and the foundation beam was simulated by the cohesive force model, and the prefabricated shear wall models with sleeve grouting defects were established. The accuracy of the simplified modeling method was verified by comparing the experimental results and numerical simulation results of the seismic performance of the prefabricated shear wall with sleeve grouting defects. The results showed that the hysteresis curve, skeleton curve, and failure mode of the numerical simulation were in good agreement with the test results. However, the stiffness of the concrete degenerated rapidly due to the apparent development of plastic-damaged concrete, which made the falling section of the hysteresis curve of the numerical simulation different from that of the test. The proposed simplified modeling method can be further applied to the performance study of prefabricated shear walls with sleeve grouting defects and can provide a reference for structural performance evaluation, design optimization, and construction quality control to a certain extent. [ABSTRACT FROM AUTHOR]

To adapt to the development trend of intelligent air combat, it is necessary to research the autonomous generation of maneuvering decisions for unmanned combat aerial vehicles (UCAV). This paper presents a maneuver decision-making method for UCAV based on a hybridization of deep Q-network (DQN) and extended Kalman filtering (EKF). Firstly, a three-dimensional air combat simulation environment is constructed, and a flight motion model of UCAV is designed to meet the requirements of the simulation environment. Secondly, we evaluate the current situation of UCAV based on their state variables in air combat, for further network learning and training to obtain the optimal maneuver strategy. Finally, based on the DQN, the system state equation is constructed using the uncertain parameter values of the current network, and the observation equation of the system is constructed using the parameters of the target network. The optimal parameter estimation value of the DQN is obtained by iteratively updating the solution through EKF. Simulation experiments have shown that this autonomous maneuver decision-making method hybridizing DQN with EKF is effective and reliable, as it can eliminate the opponent and preserve its side. [ABSTRACT FROM AUTHOR]

This paper involves a novel adaptive control approach of a flexible wing system with hysteresis nonlinearity. The usual control design strategies based on the ordinary differential equations (ODEs) are inapplicable due to the flexible wing system described in the partial differential equations (PDEs), and the design of the control algorithm becomes highly intricate. Firstly, the inverse dynamic model of hysteresis is introduced to compensate for the hysteresis nonlinearity. Considering the unknown external disturbances, an adaptive technique is utilized for compensation. Then, the direct Lyapunov approach is employed to prove the bounded stability of the system. Lastly, the effectiveness of the proposed approach is validated via simulation results. [ABSTRACT FROM AUTHOR]

This paper investigates the coordinated behaviour of the multiple Euler–Lagrange systems under diverse interactions with time delays. Specially, in the case of undirected interconnection, the proportional plus damping control strategy is proposed and the sufficient conditions of bipartite consensus are derived via energy function based approach. Subsequently, a velocity‐free controller is further developed by introducing a novel second‐order auxiliary system to each agent. In the case of directed network, by fully investigating the property of the Laplacian matrix associated with the cooperative–competitive interactions, a bipartite consensus controller is devised and the input–output property analysis of the system transfer function in frequency domain is presented. Simulation results are provided to demonstrate the effectiveness of the presented algorithms. [ABSTRACT FROM AUTHOR]

An innovative magnetostatic force sensor consisting of a laser source, a tiny cantilever beam, and a small permanent magnet was developed and used for defect inspection in ferromagnetic samples in the present article. The penetrating zone within a ferromagnetic material under the magnetic field provided by a permanent magnet was called the magnetic sensing zone (MSZ), and surface or internal defects within the MSZ were inspected by measuring the change in the magnetostatic force. This magnetostatic force could be calculated by the Maxwell tensor integrating over the surface and interface of a ferromagnetic material. Numerical and experimental results demonstrated that this sensor was reliable and could precisely inspect the defects of different sizes in ferromagnetic samples. In summary, the sensor proposed in this paper has the potential for industrial applications to detect surface and sub-surface tiny defects on ferromagnetic steel thin sheets, such as the zinc slag defect of hot galvanized sheets, cracks on cold-rolled sheets, and the ferromagnetic oscillation marks of continuous casting. [ABSTRACT FROM AUTHOR]

The accurate calculation of the natural frequencies of the stator is an important prerequisite for predicting and improving electromagnetic vibration in electrical machines. In this article, the stator core and the enclosure are regarded as cylindrical shells with axial ribs attached inside and outside the shells, respectively. Considering the moment of inertia and the shear deformation of the cylindrical shell, the displacement functions of the mid-surface in cylindrical shell are expressed as a superposition of orthogonal polynomials, the natural frequencies including axial, and circumferential modal shapes under different boundary conditions are obtained by combining the energy method and the Gram–Schmidt orthogonalization method, and the accuracy of the calculation results is verified by the finite element method and modal test. Considering the orthogonality of the stator material and specific slot structure, the natural frequencies of the stator including the stator core, windings, and enclosure are accurately obtained, the actual constraints of the end covers on the enclosure are accurately simulated by the simply supported boundary conditions. [ABSTRACT FROM AUTHOR]

The near-field wave problem of the saturated soil involves the energy radiation effect of the truncated infinite media. A viscous spring boundary is proposed for the fluid-saturated porous media. Based on the process of wave propagation under internal point source, the stress and flow velocity boundaries are constructed by reasonable assumptions of outgoing waves and Green's function, respectively. Without the permeability assumption, the proposed boundary avoids the low accuracy caused by the assumption of zero permeability that is widely used in the existing methods. The boundary simultaneously has a simple form, clear physical meaning, and less computational cost due to its local character. Meanwhile, a completely explicit integration algorithm considering the damping is constructed to solve the finite element equations of saturated porous media with the proposed boundary. The accuracy and high computational efficiency of the wave numerical method are verified in the examples. [ABSTRACT FROM AUTHOR]

An explicit finite element method is proposed to solve the u-p-formed dynamic equation of saturated porous media. In this method, a special discretization is implemented to discretize the global computational domain into local node systems of the individual nodes, and the dynamic equation of each local node system corresponding to each node is discretized by the completely explicit integration method in the time domain. By cycling through all the nodes, the dynamic responses of the global computational domain are obtained. In addition, a viscoelastic artificial boundary is added in the method. In numerical examples, the proposed FEM is verified by the good agreements between the results obtained from the proposed method and the analytical and numerical solutions of existing methods, respectively. After being embedded in OpenSees software, the proposed method is implemented into analysis of the seismic responses of liquefiable site. [ABSTRACT FROM AUTHOR]

To improve the robustness of current polarimetric dehazing scheme in the condition of low degree of polarization, we report a polarimetric dehazing method based on the image fusion technique and adaptive adjustment algorithm which can operate well in many different conditions. A splitting focus plane linear polarization camera was employed to grab the images of four different polarization directions, and the haze was separated from the hazy images by low-pass filtering roughly. Then the image fusion technique was used to optimize the method of estimating the transmittance map. To improve the quality of the dehazed images, an adaptive adjustment algorithm was introduced to adjust the illumination distribution of the dehazed images. The outdoor experiments have been implemented and the results indicated that the presented method could restore the target information obviously, and both the visual effect and quantitative evaluation have been enhanced. [ABSTRACT FROM AUTHOR]

Li metal batteries have attracted extensive research attention because of their extremely high theoretical capacity. However, the commercialization of the Li metal batteries is hindered, as uncontrolled Li dendrites growth leads to safety concerns and a low coulombic efficiency. To suppress Li dendrites growth and achieve dense Li deposition, a lithiophilic 3D Cu host is designed for Li metal anode, in which the nano‐sized Cu is in situ formed with the aid of infused Li metal. The fabricated Li metal anode exhibit a superior electrochemical stability than raw Li metal anode, and compact Li is maintained during cycling. The experimental results and density functional theory calculations demonstrate that the nano‐sized Cu formed on the surface of the skeleton host shows highly exposed Cu (100) and Cu (110) surfaces, which exhibits a strong affinity toward Li, and effectively eliminates the formation of Li dendrites, leading to a dense Li deposition. With the strategy of adjusting exposed surfaces of Cu host, the optimized Li metal anode enhances the electrochemical performance of full cells, and concomitantly demonstrates their potential for future designs of next‐generation Li metal anodes or Li‐free anodes for Li metal batteries. [ABSTRACT FROM AUTHOR]

This paper investigates the stabilization and trajectory tracking problem of wheeled mobile robot with a ceiling-mounted camera in complex environment. First, an adaptive visual servoing controller is proposed based on the uncalibrated kinematic model due to the complex operation environment. Then, an adaptive controller is derived to provide a solution of uncertain dynamic control for a wheeled mobile robot subject to parametric uncertainties. Furthermore, the proposed controllers can be applied to a more general situation where the parallelism requirement between the image plane and operation plane is no more needed. The overparameterization of regressor matrices is avoided by exploring the structure of the camera-robot system, and thus, the computational complexity of the controller can be simplified. The Lyapunov method is employed to testify the stability of a closed-loop system. Finally, simulation results are presented to demonstrate the performance of the suggested control. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries are promising energy‐storage devices because of their high theoretical energy densities. For practical Li–S batteries, reducing the amount of electrolyte used is essential for achieving the high energy densities. However, reducing the electrolyte amount leads to severe performance degradation, mainly because of sluggish deposition of discharge products (Li2S) and the accompanying passivation issue that arise from the insulating nature of Li2S. In this study, a lightweight, robust interlayer, with a 3D open structure and a low surface area is designed and fabricated. The structure facilitates electrolyte infiltration without trapping too much electrolyte. Moreover, the electrocatalytic Co nanoparticles embedded in the skeleton surface within the interlayer effectively promote Li ion diffusion, polysulfides conversion, and Li2S deposition, and therefore enhance the electrochemical kinetics under lean electrolyte conditions. The mechanisms involved in the interlayer effects are investigated by microstructural characterizations, electrochemical performance tests, density functional theory calculations, and in situ X‐ray diffraction characterization. These results show the feasibility of using an interlayer strategy to improve the electrochemical performances of Li–S batteries under lean electrolyte conditions to potentially increase the practical energy densities of Li–S batteries. [ABSTRACT FROM AUTHOR]

Summary: This paper addresses the control issue for cooperative visual servoing manipulators on strongly connected graph with communication delays, in which case that the uncertain robot dynamics and kinematics, uncalibrated camera model, and actuator constraint are simultaneously considered. An adaptive cooperative image‐based approach is established to overcome the control difficulty arising from nonlinear coupling between visual model and robot agents. To estimate the coupled camera‐robot parameters, a novel adaptive strategy is developed and its superiority mainly lies in the containment of both individual image‐space errors and the synchronous errors among networked robots; thus, the cooperative performance is significantly strengthened. Moreover, the proposed cooperative controller with a Nussbaum‐type gain is implemented to both globally stabilize the closed‐loop systems and realize the synchronization control objective under the existence of unknown and time‐varying actuator constraint. Finally, simulations are carried out to validate the developed approach. [ABSTRACT FROM AUTHOR]

This paper investigates the adaptive fuzzy visual tracking control problem for telecontrolled manipulator system with input quantized by the proposed saturation switch quantizer (SSQ). Compared with the existing logarithmic quantizer and uniform quantizer, the major superiority of this newly SSQ lies in its adjustable communication rate and quantization density, simultaneously taking the input saturation effect into account. By establishing a nonlinear decomposition-based scheme for the output of SSQ, the control difficulty caused by discrete quantized input is overcome successfully. In addition, the requirement of visual velocity in controller construction is removed by introducing a visual velocity observer, and thus, large image noises and computational burden are both avoided. Subsequently, without the exact knowledge of robot dynamics, a novel adaptive fuzzy visual servoing controller is developed to guarantee the boundedness of closed-loop signals and the tracking performance. The effectiveness of the proposed adaptive fuzzy control scheme is confirmed by comparative simulations. [ABSTRACT FROM AUTHOR]

A non-destructive assessment using visible/near-infrared spectroscopy and machine vision has been investigated for measuring tomato ripeness. Relationship between spectral wavelengths and green grayscale value was evaluated by application of chemometrics techniques based on partial least squares (PLS) regression. The tomatoes were divided randomly into two groups: 170 fruits for calibration and 71 for prediction. An accurate estimation, measured with a correlation coefficient of 0.992 and root mean square errors of prediction (RMSEP) of 9.92, was obtained when using the developed PLS model built with 550-750 nm spectral range. The accuracies of calibration and validation models based on data measured in this band were 90.93 and 90.05%. The prediction accuracy for 150 external independent samples was 90.67%. The results show that it is possible to realize detection standardization of tomato maturity based on only visible spectroscopy (550-750 nm) and machine vision technologies. This detection method does not depend on a visual grading or other maturity indices as a reference. It highlights the potential of the method to determine tomato ripeness and the optimum harvest time. [ABSTRACT FROM AUTHOR]

This paper investigates the image-based visual servoing (IBVS) manipulator system with unknown hysteresis nonlinearity by utilizing the uncalibrated eye-to-hand configuration. Compared with the conventional IBVS system, the unknown actuator hysteresis nonlinearity, which widely exists in the real physical mechanical systems and significantly limits the performances of the robotic system, is fully considered. The problem of unknown actuator nonlinearity prevents direct input of existing controllers and will result in some challenging difficulties in control design. In this paper, an adaptive IBVS control scheme, which takes the unknown actuator hysteresis into account, is presented. Without the prior knowledge of both the intervals of hysteresis parameters and the bound of the dynamic disturbance term, a novel adaptive algorithm is developed to estimate the unknown parameters on-line. The image tracking errors are guaranteed to converge to a small neighborhood of the origin. Simulations and comparative experiments are carried out to test the performance of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper focuses on a problem of adaptive visual tracking control for an uncalibrated image-based visual servoing manipulator system with actuator fuzzy dead-zone constrain and unknown dynamic. Without a prior knowledge of the system, fuzzy logic systems are employed to approximate the unmodeled nonlinear manipulator dynamics and external disturbances. By using the recursive Newton–Euler method, the total number of fuzzy rules can be reduced significantly as compared with the traditional fuzzy logic system. By defuzzifying the fuzzy slope \tilde k of the fuzzy dead-zone model to a deterministic value \bar k , a novel fuzzy adaptive controller is constructed to eliminate the harmful effect of fuzzy dead-zone constrain. Lyapunov functions are presented for stability analysis of visual feedback control problem with unknown dynamics and actuator fuzzy dead-zone constrains. Experimental results are carried out to test the visual tracking performance of the proposed controller and the boundedness of the closed-loop system. [ABSTRACT FROM AUTHOR]

As a process for producing seamless tubes, the tandem skew rolling (TSR) process was proposed. In order to study deformation characteristics and mechanism on tubes obtained by the TSR process, a numerical simulation of the process was analyzed using Deform-3D software. Simulation results demonstrated the distribution of stress, strain, velocity, and temperature of a seamless tube in the stable stage during the TSR process. Actual experiments of carbon steel 1045, high strength steel 42CrMo, and magnesium alloy AZ31 were carried out in a TSR testing mill. The results demonstrated that the TSR process is qualified for producing tubes of high quality, with an accuracy of ±0.2 mm in wall thickness and ±0.35 mm in diameter. This process is suitable for manufacturing seamless tubes that are difficult to deform or that have been deformed in a narrow range of temperature. [ABSTRACT FROM AUTHOR]

Considering the market demand for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) as energy storage devices, it is necessary to find a negative electrode material with low cost, high specific capacity, and long cycle life. CuO has a high theoretical specific capacity and therefore has broad application prospects. This study reports a freestanding nitrogen‐doped carbon‐coated CuO array (NC‐CuO)‐based anode obtained by synthesizing CuO nanorods on a Cu net and depositing nitrogen‐doped carbon on the surface of the nanorods. The NC‐CuO array anode fully utilizes the synergistic advantages of the 3D array and the outer N‐doped carbon layer, which effectively enhance the electronic conductivity of the metal oxide and alleviate the volume change during Li/Na ion insertion and extraction. It is found that the NC‐CuO array as the anode material for LIBs has a capacity of 562.5 mAhg−1 and a cycle stability of more than 200 cycles even at a high current density of 500 mAg−1. SIBs with the NC‐CuO array anode also exhibit excellent electrochemical performance. [ABSTRACT FROM AUTHOR]