The combination of silicon carbide(SiC)ceramics and stereolithography technology shows promise for manufacturing complex-shaped SiC components,expanding application possibilities.However,high sintering temperature and...The combination of silicon carbide(SiC)ceramics and stereolithography technology shows promise for manufacturing complex-shaped SiC components,expanding application possibilities.However,high sintering temperature and structural-performance anisotropy limit the practical use of 3D-printed SiC components.Herein,a novel method is introduced to produce high-specific-strength SiC-based ceramics at a relatively low temperature of 1100℃.A mixed SiC/SiO_(2) slurry(30%SiO_(2) and 70%SiC by volume)with a solid loading of up to 40%was prepared to improve UV light penetration and printability.Additionally,incorporating a high content of methyl-phenyl-polysiloxane(PSO)solution(75%by weight)enabled low-temperature pyrolysis of SiC/SiO_(2)/PSO ceramics.The SiC/SiO_(2)/PSO ceramic lattices after pyrolysis achieved a specific strength as high as(1.03×10^(5))N·m·kg^(-1) and a density of 1.75 g·cm^(-3),outperforming similar SiC-based lattices structures of similar porosities.The bending strength of(95.49±8.79)MPa was comparable to that of ceramics sintered at 1400℃ or higher.Notably,the addition of the silicon carbide oxide(SiOC)phase reduced anisotropy,lowering the transverse and longitudinal compression strength ratios from 1.87 to 1.08,and improving mechanical properties by 79%.This improvement is attributed to SiOC shrinkage,promoting a uniform distribution of sintered components,resulting in a more robust and balanced material structure.This method offers valuable insight into the additive manufacturing(AM)of SiC-based ceramics at lower temperatures and provides new guidance for controlling anisotropy in 3D-printed ceramic parts.展开更多
Legged robots have always been a focal point of research for scholars domestically and internationally.Compared to other types of robots,quadruped robots exhibit superior balance and stability,enabling them to adapt e...Legged robots have always been a focal point of research for scholars domestically and internationally.Compared to other types of robots,quadruped robots exhibit superior balance and stability,enabling them to adapt effectively to diverse environments and traverse rugged terrains.This makes them well-suited for applications such as search and rescue,exploration,and transportation,with strong environmental adaptability,high flexibility,and broad application prospects.This paper discusses the current state of research on quadruped robots in terms of development status,gait trajectory planning methods,motion control strategies,reinforcement learning applications,and control algorithm integration.It highlights advancements in modeling,optimization,control,and data-driven approaches.The study identifies the adoption of efficient gait planning algorithms,the integration of reinforcement learning-based control technologies,and data-driven methods as key directions for the development of quadruped robots.The aim is to provide theoretical references for researchers in the field of quadruped robotics.展开更多
To address the limitations of traditional manual highway guardrail inspections,this paper proposes an obstacle-crossing and collaborative tracking control method for a rail-mounted robot.Static and dynamic analyses ve...To address the limitations of traditional manual highway guardrail inspections,this paper proposes an obstacle-crossing and collaborative tracking control method for a rail-mounted robot.Static and dynamic analyses verify the robot's structural reliability and driving feasibility.Based on the leader-follower model,a triangular collaborative tracking model is developed,and a linear time-varying model predictive controll(LTV-MPC)is designed to achieve smooth and precise collaborative control.For obstacle crossing,an acceleration reference model and a gradient-based adaptive law are proposed,leading to a model reference adaptive controll(MRAC)that effectively suppresses vibrations and ensures synchronous control.Simulation results show that the MPC achieves a 0.415%overshoot and a 0.344 m steady-state accuracy,while also reducing the intensity of speed fluctuations by 35%.The MRAC ensures smooth obstacle-crossing speeds and adaptive strategy switching,validating the reliability and practicality of the rail-mounted robot under complex working conditions.展开更多
Over the past decade,artificial intelligence(AI)has evolved at an unprecedented pace,transforming technology,industry,and society.From diagnosing diseases with remarkable accuracy to powering self-driving cars and rev...Over the past decade,artificial intelligence(AI)has evolved at an unprecedented pace,transforming technology,industry,and society.From diagnosing diseases with remarkable accuracy to powering self-driving cars and revolutionizing personalized learning,AI is reshaping our world in ways once thought impossible.Spanning fields such as machine learning,deep learning,natural language processing,robotics,and ChatGPT,AI continues to push the boundaries of innovation.As AI continues to advance,it is vital to have a platform that not only disseminates cutting-edge research innovations but also fosters broad discussions on its societal impact,ethical considerations,and interdisciplinary applications.With this vision in mind,we proudly introduce Artificial Intelligence Science and Engineering(AISE)-a journal dedicated to nurturing the next wave of AI innovation and engineering applications.Our mission is to provide a premier outlet where researchers can share high-quality,impactful studies and collaborate to advance AI across academia,industry,and beyond.展开更多
Predictive control(PC)is an advanced control algorithm,which is widely used in industrial process control.Among them,model-based predictive control(MPC)is an important branch of predictive control.Its basic principle ...Predictive control(PC)is an advanced control algorithm,which is widely used in industrial process control.Among them,model-based predictive control(MPC)is an important branch of predictive control.Its basic principle is to use the system model to predict future behavior and determine the current control action by optimizing the objective function.Based on the algorithm combined with three different sections using deep learning technology to identify vehicles and output the optimal speed limit,to achieve the effect of traffic flow optimization.展开更多
To enhance energy interaction among low-voltage stations(LVSs)and reduce the line loss of the distribution network,a novel operation mode of the micro-pumped storage system(mPSS)has been proposed based on the common r...To enhance energy interaction among low-voltage stations(LVSs)and reduce the line loss of the distribution network,a novel operation mode of the micro-pumped storage system(mPSS)has been proposed based on the common reservoir.First,some operation modes of mPSS are analyzed,which include the separated reservoir mode(SRM)and common reservoir mode(CRM).Then,based on the SRM,and CRM,an energy mutual assistance control model between LVSs has been built to optimize energy loss.Finally,in the simulation,compared to the model without pumped storage in the LVS,the SRMand CLRMcan decrease the total energy loss by 294.377 and 432.578 kWh,respectively.The configuration of mPSS can improve the utilization rate of the new energy source generation system,and relieve the pressure of transformer capacity in the LVS.Compared with the SRM,the proposed CRM has reduced the total energy loss by 138.201 kWh,increased the new energy consumption by 161.642 kWh,and decreased the line loss by 7.271 kWh.With the efficiency of the mPSS improving,the total energy loss reduction of CRM will be 3.5 times that of SRM.Further,the CRMcan significantly reduce the reservoir capacity construction of mPSS and ismore suitable for scenarios where the capacity configuration of mPSS is limited.展开更多
Shale gas wells often face challenges in maintaining continuous and stable production due to their coexistence with high-and low-pressure wells within the same development block,which leads to issues involving mixed-p...Shale gas wells often face challenges in maintaining continuous and stable production due to their coexistence with high-and low-pressure wells within the same development block,which leads to issues involving mixed-pressure flows.Traditional pipeline optimization methods used in conventional gas well blocks fail to address the unique needs of shale gas wells,such as the precise planning of airflow paths,pressure distribution,and compression.This study proposes a pressure-controlled production optimization strategy specifically designed for shale gas wells operating under mixed-pressure flow conditions.The strategy aims to improve production stability and optimize system efficiency.The decline in production and pressure for individual wells over time is forecasted using a predictive model that accounts for key factors of system optimization,such as reservoir depletion,wellbore conditions,and equipment performance.Additionally,the model predicts the timing and impact of liquid loading,which can significantly affect production.The optimization process involves analyzing the existing gathering pipeline network to determine the most efficient flow directions and compression strategies based on these predictions,while the strategy involves adjusting compressor settings,optimizing flow rates,and planning pressure distribution across the network to maximize productivity while maintaining system stability.By implementing these strategies,this study significantly improves gas well productivity and enhances the adaptability and efficiency of the gathering and transportation system.The proposed approach provides systematic technical solutions and practical guidance for the efficient development and stable production of shale gas fields,ensuring more robust and sustainable pipeline operations.展开更多
With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to...With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to ensure closed-loop stability when employing a time-varying bandwidth,as well as the supporting mathematical foundations,remain insufficiently studied.This paper investigates the stability condition for active disturbance rejection control(ADRC)with a time-varying bandwidth extended state observer(ESO).A new stability condition is derived,which means that the upper bound of rate of change for ESO bandwidth should be restricted.Moreover,under the proposed condition,the closed-loop stability of ADRC with a time-varying bandwidth observer is rigorously proved for nonlinear uncertainties.In simulations,the necessity of the proposed condition is illustrated,demonstrating that the rate of change of ESO bandwidth is crucial for closed-loop stability.展开更多
CO_(2) hydrogenation to CH3OH is of great significance for achieving carbon neutrality.Here,we show a urea-assisted grinding strategy for synthesizing Cu-Zn-Ce ternary catalysts(CZC-G)with optimized interfacial synerg...CO_(2) hydrogenation to CH3OH is of great significance for achieving carbon neutrality.Here,we show a urea-assisted grinding strategy for synthesizing Cu-Zn-Ce ternary catalysts(CZC-G)with optimized interfacial synergy,achieving superior performance in CO_(2) hydrogenation to methanol.The CZC-G catalyst demonstrated exceptional methanol selectivity(96.8%)and a space-time yield of 73.6 gMeOH·kgcat^(–1)·h^(–1) under optimized conditions.Long-term stability tests confirmed no obvious deactivation over 100 h of continuous operation.Structural and mechanistic analyses revealed that the urea-assisted grinding method promotes the formation of Cu/Zn-O_(v)-Ce ternary interfaces and inhibits the reduction of ZnO,enabling synergistic interactions for efficient CO_(2) activation and selective stabilization of formate intermediates(HCOO^(*)),which are critical for methanol synthesis.In-situ diffuse reflectance infrared Fourier transform spectra and X-ray absorption spectroscopy studies elucidated the reaction pathway dominated by the formate mechanism,while suppressing the reverse water-gas shift reaction.This work underscores the critical role of synthetic methodologies in engineering interfacial structures,offering a strategy for designing high-performance catalysts for sustainable CO_(2) resource utilization.展开更多
The finite/fixed-time stabilization and tracking control is currently a hot field in various systems since the faster convergence can be obtained. By contrast to the asymptotic stability,the finite-time stability poss...The finite/fixed-time stabilization and tracking control is currently a hot field in various systems since the faster convergence can be obtained. By contrast to the asymptotic stability,the finite-time stability possesses the better control performance and disturbance rejection property. Different from the finite-time stability, the fixed-time stability has a faster convergence speed and the upper bound of the settling time can be estimated. Moreover, the convergent time does not rely on the initial information.This work aims at presenting an overview of the finite/fixed-time stabilization and tracking control and its applications in engineering systems. Firstly, several fundamental definitions on the finite/fixed-time stability are recalled. Then, the research results on the finite/fixed-time stabilization and tracking control are reviewed in detail and categorized via diverse input signal structures and engineering applications. Finally, some challenging problems needed to be solved are presented.展开更多
Cemented and mechanically clamped types of end fittings(fitting-C and fitting-M)are commonly used in transformer bushings.During the Luding Ms 6.8 earthquake that occurred in China on September 5,2022,all transformer ...Cemented and mechanically clamped types of end fittings(fitting-C and fitting-M)are commonly used in transformer bushings.During the Luding Ms 6.8 earthquake that occurred in China on September 5,2022,all transformer bushings with the two types of end fittings in a 500 kV substation were damaged.Post-earthquake field investigations were conducted,and the failures of the two types of bushings were compared.Two elementary simulation models of the transformer-bushing systems were developed to simulate the engineering failures,and further compute their seismic responses for comparison.The results indicate that the hitch lugs of the connection flange are structurally harmful to seismic resistance.Fitting-M can decrease the bending stiffness of the bushing due to the flexible sealing rubber gasket.Since it provides a more flexible connection that dissipates energy,the peak accelerations and relative displacements at the top of the bushing are significantly lower than those of the bushing with fitting-C.Compared with fitting-C,fitting-M transfers the high-stress areas from the connection flange to the root of the porcelain,so the latter becomes the most vulnerable component.Fitting-M increases the failure risk of the low-strength porcelain,indicating the unsuitability of applying it in high-intensity fortification regions.展开更多
Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and ...Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.展开更多
Hydrogen peroxide(H_(2)O_(2))is one of the 100 most important chemicals in the world with high energy density and environmental friendliness.Compared with anthraquinone oxidation,direct synthesis of H_(2)O_(2) with hy...Hydrogen peroxide(H_(2)O_(2))is one of the 100 most important chemicals in the world with high energy density and environmental friendliness.Compared with anthraquinone oxidation,direct synthesis of H_(2)O_(2) with hydrogen(H_(2))and oxygen(O_(2)),and electrochemical methods,photocatalysis has the characteristics of low energy consumption,easy operation and less pollution,and broad application prospects in H_(2)O_(2) generation.Various photocatalysts,such as titanium dioxide(TiO_(2)),graphitic carbon nitride(g-C_(3)N_(4)),metal-organic materials,and nonmetallic materials,have been studied for H_(2)O_(2) production.Among them,g-C_(3)N_(4) materials,which are simple to synthesize and functionalize,have attracted wide attention.The electronic band structure of g-C_(3)N_(4) shows a bandgap of 2.77 eV,a valence band maximum of 1.44 V,and a conduction band minimum of−1.33 V,which theoretically meets the requirements for hydrogen peroxide production.In comparison to semiconductor materials like TiO_(2)(3.2 eV),this material has a smaller bandgap,which results in a more efficient response to visible light.However,the photocatalytic activity of g-C_(3)N_(4) and the yield of H_(2)O_(2) were severely inhibited by the electron-hole pair with high recombination rate,low utilization rate of visible light,and poor selectivity of products.Although previous reviews also presented various strategies to improve photocatalytic H_(2)O_(2) production,they did not systematically elaborate the inherent relationship between the control strategies and their energy band structure.From this point of view,this article focuses on energy band engineering and reviews the latest research progress of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production.On this basis,a strategy to improve the H_(2)O_(2) production by g-C_(3)N_(4) photocatalysis is proposed through morphology control,crystallinity and defect,and doping,combined with other materials and other strategies.Finally,the challenges and prospects of industrialization of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production are discussed and envisioned.展开更多
This paper studies the target controllability of multilayer complex networked systems,in which the nodes are highdimensional linear time invariant(LTI)dynamical systems,and the network topology is directed and weighte...This paper studies the target controllability of multilayer complex networked systems,in which the nodes are highdimensional linear time invariant(LTI)dynamical systems,and the network topology is directed and weighted.The influence of inter-layer couplings on the target controllability of multi-layer networks is discussed.It is found that even if there exists a layer which is not target controllable,the entire multi-layer network can still be target controllable due to the inter-layer couplings.For the multi-layer networks with general structure,a necessary and sufficient condition for target controllability is given by establishing the relationship between uncontrollable subspace and output matrix.By the derived condition,it can be found that the system may be target controllable even if it is not state controllable.On this basis,two corollaries are derived,which clarify the relationship between target controllability,state controllability and output controllability.For the multi-layer networks where the inter-layer couplings are directed chains and directed stars,sufficient conditions for target controllability of networked systems are given,respectively.These conditions are easier to verify than the classic criterion.展开更多
The helicopter Trailing-Edge Flaps(TEFs)technology is one of the recent hot topics in morphing wing research.By employing controlled deflection,TEFs can effectively reduce the vibration level of helicopters.Thus,desig...The helicopter Trailing-Edge Flaps(TEFs)technology is one of the recent hot topics in morphing wing research.By employing controlled deflection,TEFs can effectively reduce the vibration level of helicopters.Thus,designing specific vibration reduction control methods for the helicopters equipped with trailing-edge flaps is of significant practical value.This paper studies the optimal control problem for helicopter-vibration systems with TEFs under the framework of adaptive dynamic programming combined with Reinforcement Learning(RL).Time-delay and disturbances,caused by complexity of helicopter dynamics,inevitably deteriorate the control performance of vibration reduction.To solve this problem,a zero-sum game formulation with a linear quadratic form for reducing vibration of helicopter systems is presented with a virtual predictor.In this context,an off-policy reinforcement learning algorithm is developed to determine the optimal control policy.The algorithm utilizes only vertical vibration load data to achieve a policy that reduces vibration,attains Nash equilibrium,and addresses disturbances while compensating for time-delay without knowledge of the dynamics of the helicopter system.The effectiveness of the proposed method is demonstrated in a virtual platform.展开更多
A distributionally robust model predictive control(DRMPC)scheme is proposed based on neural network(NN)modeling to achieve the trajectory tracking control of robot manipulators with state and control torque constraint...A distributionally robust model predictive control(DRMPC)scheme is proposed based on neural network(NN)modeling to achieve the trajectory tracking control of robot manipulators with state and control torque constraints.First,an NN is used to fit the motion data of robot manipulators for data-driven dynamic modeling,converting it into a linear prediction model through gradients.Then,by statistically analyzing the stochastic characteristics of the NN modeling errors,a distributionally robust model predictive controller is designed based on the chance constraints,and the optimization problem is transformed into a tractable quadratic programming(QP)problem under the distributionally robust optimization(DRO)framework.The recursive feasibility and convergence of the proposed algorithm are proven.Finally,the effectiveness of the proposed algorithm is verified through numerical simulation.展开更多
An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input sat...An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.First,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the system.Then,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.Based on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation method.According to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric constraint.Finally,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.展开更多
A modular system of cascaded converters based on model predictive control(MPC)is proposed to meet the application requirements ofmultiple voltage levels and electrical isolation in renewable energy generation systems....A modular system of cascaded converters based on model predictive control(MPC)is proposed to meet the application requirements ofmultiple voltage levels and electrical isolation in renewable energy generation systems.The system consists of a Buck/Boost+CLLLC cascaded converter as a submodule,which is combined in series and parallel on the input and output sides to achieve direct-current(DC)voltage transformation,bidirectional energy flow,and electrical isolation.The CLLLC converter operates in DC transformer mode in the submodule,while the Buck/Boost converter participates in voltage regulation.This article establishes a suitable mathematical model for the proposed system topology,and uses MPC to control the system based on this mathematical model.Module parameters are designed and calculated,and simulation is built in MATLAB/Simulink to complete the simulation comparison experiment between MPC and traditional proportional integral(PI)control.Finally,a physical experimental platform is built to complete the physical comparison experiment.The simulation and physical experimental results prove that the control accuracy and response speed ofMPC are better than traditional PI control strategy.展开更多
As a new grinding and maintenance technology,rail belt grinding shows significant advantages in many applications The dynamic characteristics of the rail belt grinding vehicle largely determines its grinding performan...As a new grinding and maintenance technology,rail belt grinding shows significant advantages in many applications The dynamic characteristics of the rail belt grinding vehicle largely determines its grinding performance and service life.In order to explore the vibration control method of the rail grinding vehicle with abrasive belt,the vibration response changes in structural optimization and lightweight design are respectively analyzed through transient response and random vibration simulations in this paper.Firstly,the transient response simulation analysis of the rail grinding vehicle with abrasive belt is carried out under operating conditions and non-operating conditions.Secondly,the vibration control of the grinding vehicle is implemented by setting vibration isolation elements,optimizing the structure,and increasing damping.Thirdly,in order to further explore the dynamic characteristics of the rail grinding vehicle,the random vibration simulation analysis of the grinding vehicle is carried out under the condition of the horizontal irregularity of the American AAR6 track.Finally,by replacing the Q235 steel frame material with 7075 aluminum alloy and LA43M magnesium alloy,both vibration control and lightweight design can be achieved simultaneously.The results of transient dynamic response analysis show that the acceleration of most positions in the two working conditions exceeds the standard value in GB/T 17426-1998 standard.By optimizing the structure of the grinding vehicle in three ways,the average vibration acceleration of the whole car is reduced by about 55.1%from 15.6 m/s^(2) to 7.0 m/s^(2).The results of random vibration analysis show that the grinding vehicle with Q235 steel frame does not meet the safety conditions of 3σ.By changing frame material,the maximum vibration stress of the vehicle can be reduced from 240.7 MPa to 160.0 MPa and the weight of the grinding vehicle is reduced by about 21.7%from 1500 kg to 1175 kg.The modal analysis results indicate that the vibration control of the grinding vehicle can be realized by optimizing the structure and replacing the materials with lower stiffness under the premise of ensuring the overall strength.The study provides the basis for the development of lightweight,diversified and efficient rail grinding equipment.展开更多
In recent years,intelligent robots are extensively applied in the field of the industry and intelligent rehabilitation,wherein the human-robot interaction(HRI)control strategy is a momentous part that needs to be amel...In recent years,intelligent robots are extensively applied in the field of the industry and intelligent rehabilitation,wherein the human-robot interaction(HRI)control strategy is a momentous part that needs to be ameliorated.Specially,the efficacy and robustness of the HRI control algorithm in the presence of unknown external disturbances deserve to be addressed.To deal with these urgent issues,in this study,artificial systems,computational experiments and a parallel execution intelligent control framework are constructed for the HRI control.The upper limb-robotic exoskeleton system is re-modelled as an artificial system.Depending on surface electromyogram-based subject's active motion intention in the practical system,a non-convex function activated anti-disturbance zeroing neurodynamic(NC-ADZND)controller is devised in the artificial system for parallel interaction and HRI control with the practical system.Furthermore,the linear activation function-based zeroing neurodynamic(LAF-ZND)controller and proportionalderivative(posterior deltoid(PD))controller are presented and compared.Theoretical results substantiate the global convergence and robustness of the proposed controller in the presence of different external disturbances.In addition,the simulation results verify that the NC-ADZND controller is better than the LAF-ZND and the PD controllers in respect of convergence order and anti-disturbance characteristics.展开更多
基金financially supported by the Key Project of Department of Education of Guangdong Province(Grant No.2022ZDZX3017)Special Support Plan of Guangdong Province(Grant No.2021TQ05Z151)+2 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515010049)SZU Research Fund(Grant No.GFPY-YB-2024-03)Shenzhen Science and Technology Programs(Grant Nos.GJHZ20210705141803011 and 20200731211324001).
文摘The combination of silicon carbide(SiC)ceramics and stereolithography technology shows promise for manufacturing complex-shaped SiC components,expanding application possibilities.However,high sintering temperature and structural-performance anisotropy limit the practical use of 3D-printed SiC components.Herein,a novel method is introduced to produce high-specific-strength SiC-based ceramics at a relatively low temperature of 1100℃.A mixed SiC/SiO_(2) slurry(30%SiO_(2) and 70%SiC by volume)with a solid loading of up to 40%was prepared to improve UV light penetration and printability.Additionally,incorporating a high content of methyl-phenyl-polysiloxane(PSO)solution(75%by weight)enabled low-temperature pyrolysis of SiC/SiO_(2)/PSO ceramics.The SiC/SiO_(2)/PSO ceramic lattices after pyrolysis achieved a specific strength as high as(1.03×10^(5))N·m·kg^(-1) and a density of 1.75 g·cm^(-3),outperforming similar SiC-based lattices structures of similar porosities.The bending strength of(95.49±8.79)MPa was comparable to that of ceramics sintered at 1400℃ or higher.Notably,the addition of the silicon carbide oxide(SiOC)phase reduced anisotropy,lowering the transverse and longitudinal compression strength ratios from 1.87 to 1.08,and improving mechanical properties by 79%.This improvement is attributed to SiOC shrinkage,promoting a uniform distribution of sintered components,resulting in a more robust and balanced material structure.This method offers valuable insight into the additive manufacturing(AM)of SiC-based ceramics at lower temperatures and provides new guidance for controlling anisotropy in 3D-printed ceramic parts.
基金funded by the Natural Science Basis Research Plan in Shaanxi Province of China(Program No.2023-JC-QN-0659)General Specialized Scientific Research Program of the Shaanxi Provincial Department of Education(Program 23JK0349).
文摘Legged robots have always been a focal point of research for scholars domestically and internationally.Compared to other types of robots,quadruped robots exhibit superior balance and stability,enabling them to adapt effectively to diverse environments and traverse rugged terrains.This makes them well-suited for applications such as search and rescue,exploration,and transportation,with strong environmental adaptability,high flexibility,and broad application prospects.This paper discusses the current state of research on quadruped robots in terms of development status,gait trajectory planning methods,motion control strategies,reinforcement learning applications,and control algorithm integration.It highlights advancements in modeling,optimization,control,and data-driven approaches.The study identifies the adoption of efficient gait planning algorithms,the integration of reinforcement learning-based control technologies,and data-driven methods as key directions for the development of quadruped robots.The aim is to provide theoretical references for researchers in the field of quadruped robotics.
基金Supported by the Shaanxi Provincial Key Research and Development Program(2024GX-YBXM-288)the Science and Technology Project of Shaanxi Provincial Transportation Department(21-20K)the National Natural Science Foundation of China(52172324)。
文摘To address the limitations of traditional manual highway guardrail inspections,this paper proposes an obstacle-crossing and collaborative tracking control method for a rail-mounted robot.Static and dynamic analyses verify the robot's structural reliability and driving feasibility.Based on the leader-follower model,a triangular collaborative tracking model is developed,and a linear time-varying model predictive controll(LTV-MPC)is designed to achieve smooth and precise collaborative control.For obstacle crossing,an acceleration reference model and a gradient-based adaptive law are proposed,leading to a model reference adaptive controll(MRAC)that effectively suppresses vibrations and ensures synchronous control.Simulation results show that the MPC achieves a 0.415%overshoot and a 0.344 m steady-state accuracy,while also reducing the intensity of speed fluctuations by 35%.The MRAC ensures smooth obstacle-crossing speeds and adaptive strategy switching,validating the reliability and practicality of the rail-mounted robot under complex working conditions.
文摘Over the past decade,artificial intelligence(AI)has evolved at an unprecedented pace,transforming technology,industry,and society.From diagnosing diseases with remarkable accuracy to powering self-driving cars and revolutionizing personalized learning,AI is reshaping our world in ways once thought impossible.Spanning fields such as machine learning,deep learning,natural language processing,robotics,and ChatGPT,AI continues to push the boundaries of innovation.As AI continues to advance,it is vital to have a platform that not only disseminates cutting-edge research innovations but also fosters broad discussions on its societal impact,ethical considerations,and interdisciplinary applications.With this vision in mind,we proudly introduce Artificial Intelligence Science and Engineering(AISE)-a journal dedicated to nurturing the next wave of AI innovation and engineering applications.Our mission is to provide a premier outlet where researchers can share high-quality,impactful studies and collaborate to advance AI across academia,industry,and beyond.
文摘Predictive control(PC)is an advanced control algorithm,which is widely used in industrial process control.Among them,model-based predictive control(MPC)is an important branch of predictive control.Its basic principle is to use the system model to predict future behavior and determine the current control action by optimizing the objective function.Based on the algorithm combined with three different sections using deep learning technology to identify vehicles and output the optimal speed limit,to achieve the effect of traffic flow optimization.
基金sponsored by the State Grid Corporation of China Technology Project(Research on Key Technologies and Equipment Development of Micro Pumped Storage for Distributed New Energy Consumption in Distribution Networks,5400-202324196A-1-1-ZN).
文摘To enhance energy interaction among low-voltage stations(LVSs)and reduce the line loss of the distribution network,a novel operation mode of the micro-pumped storage system(mPSS)has been proposed based on the common reservoir.First,some operation modes of mPSS are analyzed,which include the separated reservoir mode(SRM)and common reservoir mode(CRM).Then,based on the SRM,and CRM,an energy mutual assistance control model between LVSs has been built to optimize energy loss.Finally,in the simulation,compared to the model without pumped storage in the LVS,the SRMand CLRMcan decrease the total energy loss by 294.377 and 432.578 kWh,respectively.The configuration of mPSS can improve the utilization rate of the new energy source generation system,and relieve the pressure of transformer capacity in the LVS.Compared with the SRM,the proposed CRM has reduced the total energy loss by 138.201 kWh,increased the new energy consumption by 161.642 kWh,and decreased the line loss by 7.271 kWh.With the efficiency of the mPSS improving,the total energy loss reduction of CRM will be 3.5 times that of SRM.Further,the CRMcan significantly reduce the reservoir capacity construction of mPSS and ismore suitable for scenarios where the capacity configuration of mPSS is limited.
基金supported by the National Natural Science Foundation of China under Grant 52325402,52274057 and 52074340the National Key R&D Program of China under Grant 2023YFB4104200+1 种基金the Major Scientific and Technological Projects of CNOOC under Grant CCL2022RCPS0397RSN111 Project under Grant B08028.
文摘Shale gas wells often face challenges in maintaining continuous and stable production due to their coexistence with high-and low-pressure wells within the same development block,which leads to issues involving mixed-pressure flows.Traditional pipeline optimization methods used in conventional gas well blocks fail to address the unique needs of shale gas wells,such as the precise planning of airflow paths,pressure distribution,and compression.This study proposes a pressure-controlled production optimization strategy specifically designed for shale gas wells operating under mixed-pressure flow conditions.The strategy aims to improve production stability and optimize system efficiency.The decline in production and pressure for individual wells over time is forecasted using a predictive model that accounts for key factors of system optimization,such as reservoir depletion,wellbore conditions,and equipment performance.Additionally,the model predicts the timing and impact of liquid loading,which can significantly affect production.The optimization process involves analyzing the existing gathering pipeline network to determine the most efficient flow directions and compression strategies based on these predictions,while the strategy involves adjusting compressor settings,optimizing flow rates,and planning pressure distribution across the network to maximize productivity while maintaining system stability.By implementing these strategies,this study significantly improves gas well productivity and enhances the adaptability and efficiency of the gathering and transportation system.The proposed approach provides systematic technical solutions and practical guidance for the efficient development and stable production of shale gas fields,ensuring more robust and sustainable pipeline operations.
基金supported partially by the National Natural Science Foundation(No.62473344)the T-Flight Laboratory in ShanXi Provincial(No.GSFC2024NBKY05)+1 种基金the Natural Science Basic Research Program of Shaanxi(No.2025JC-YBQN-035)the National Natural Science Foundation of China(Grant No.92471204).
文摘With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to ensure closed-loop stability when employing a time-varying bandwidth,as well as the supporting mathematical foundations,remain insufficiently studied.This paper investigates the stability condition for active disturbance rejection control(ADRC)with a time-varying bandwidth extended state observer(ESO).A new stability condition is derived,which means that the upper bound of rate of change for ESO bandwidth should be restricted.Moreover,under the proposed condition,the closed-loop stability of ADRC with a time-varying bandwidth observer is rigorously proved for nonlinear uncertainties.In simulations,the necessity of the proposed condition is illustrated,demonstrating that the rate of change of ESO bandwidth is crucial for closed-loop stability.
文摘CO_(2) hydrogenation to CH3OH is of great significance for achieving carbon neutrality.Here,we show a urea-assisted grinding strategy for synthesizing Cu-Zn-Ce ternary catalysts(CZC-G)with optimized interfacial synergy,achieving superior performance in CO_(2) hydrogenation to methanol.The CZC-G catalyst demonstrated exceptional methanol selectivity(96.8%)and a space-time yield of 73.6 gMeOH·kgcat^(–1)·h^(–1) under optimized conditions.Long-term stability tests confirmed no obvious deactivation over 100 h of continuous operation.Structural and mechanistic analyses revealed that the urea-assisted grinding method promotes the formation of Cu/Zn-O_(v)-Ce ternary interfaces and inhibits the reduction of ZnO,enabling synergistic interactions for efficient CO_(2) activation and selective stabilization of formate intermediates(HCOO^(*)),which are critical for methanol synthesis.In-situ diffuse reflectance infrared Fourier transform spectra and X-ray absorption spectroscopy studies elucidated the reaction pathway dominated by the formate mechanism,while suppressing the reverse water-gas shift reaction.This work underscores the critical role of synthetic methodologies in engineering interfacial structures,offering a strategy for designing high-performance catalysts for sustainable CO_(2) resource utilization.
基金partially supported by the National Natural Science Foundation of China(62003097,62121004,62033003,62073019)the Local Innovative and Research Teams Project of Guangdong Special Support Program(2019BT02X353)+2 种基金the Key Area Research and Development Program of Guangdong Province(2021B0101410005)the Joint Funds of Guangdong Basic and Applied Basic Research Foundation(2019A1515110505)。
文摘The finite/fixed-time stabilization and tracking control is currently a hot field in various systems since the faster convergence can be obtained. By contrast to the asymptotic stability,the finite-time stability possesses the better control performance and disturbance rejection property. Different from the finite-time stability, the fixed-time stability has a faster convergence speed and the upper bound of the settling time can be estimated. Moreover, the convergent time does not rely on the initial information.This work aims at presenting an overview of the finite/fixed-time stabilization and tracking control and its applications in engineering systems. Firstly, several fundamental definitions on the finite/fixed-time stability are recalled. Then, the research results on the finite/fixed-time stabilization and tracking control are reviewed in detail and categorized via diverse input signal structures and engineering applications. Finally, some challenging problems needed to be solved are presented.
基金National Natural Science Foundation of China under Grant No.51878508。
文摘Cemented and mechanically clamped types of end fittings(fitting-C and fitting-M)are commonly used in transformer bushings.During the Luding Ms 6.8 earthquake that occurred in China on September 5,2022,all transformer bushings with the two types of end fittings in a 500 kV substation were damaged.Post-earthquake field investigations were conducted,and the failures of the two types of bushings were compared.Two elementary simulation models of the transformer-bushing systems were developed to simulate the engineering failures,and further compute their seismic responses for comparison.The results indicate that the hitch lugs of the connection flange are structurally harmful to seismic resistance.Fitting-M can decrease the bending stiffness of the bushing due to the flexible sealing rubber gasket.Since it provides a more flexible connection that dissipates energy,the peak accelerations and relative displacements at the top of the bushing are significantly lower than those of the bushing with fitting-C.Compared with fitting-C,fitting-M transfers the high-stress areas from the connection flange to the root of the porcelain,so the latter becomes the most vulnerable component.Fitting-M increases the failure risk of the low-strength porcelain,indicating the unsuitability of applying it in high-intensity fortification regions.
基金supported in part by the National Natural Science Foundation of China(62222301, 62073085, 62073158, 61890930-5, 62021003)the National Key Research and Development Program of China (2021ZD0112302, 2021ZD0112301, 2018YFC1900800-5)Beijing Natural Science Foundation (JQ19013)。
文摘Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.
基金This work was supported by the National Natural Science Foundation of China(42307566,22205084)China Postdoctoral Science Foundation(2023M742199,2023M741039)+1 种基金This project was fundedby the National&Local Joint Engineering Research Center for Mineral Salt Deep Utilization(SF202303)the State Key Laboratory of Efficient Utilization for LowGrade Phosphate Rock and Its Associated ResourcesWFKF(2023)013.
文摘Hydrogen peroxide(H_(2)O_(2))is one of the 100 most important chemicals in the world with high energy density and environmental friendliness.Compared with anthraquinone oxidation,direct synthesis of H_(2)O_(2) with hydrogen(H_(2))and oxygen(O_(2)),and electrochemical methods,photocatalysis has the characteristics of low energy consumption,easy operation and less pollution,and broad application prospects in H_(2)O_(2) generation.Various photocatalysts,such as titanium dioxide(TiO_(2)),graphitic carbon nitride(g-C_(3)N_(4)),metal-organic materials,and nonmetallic materials,have been studied for H_(2)O_(2) production.Among them,g-C_(3)N_(4) materials,which are simple to synthesize and functionalize,have attracted wide attention.The electronic band structure of g-C_(3)N_(4) shows a bandgap of 2.77 eV,a valence band maximum of 1.44 V,and a conduction band minimum of−1.33 V,which theoretically meets the requirements for hydrogen peroxide production.In comparison to semiconductor materials like TiO_(2)(3.2 eV),this material has a smaller bandgap,which results in a more efficient response to visible light.However,the photocatalytic activity of g-C_(3)N_(4) and the yield of H_(2)O_(2) were severely inhibited by the electron-hole pair with high recombination rate,low utilization rate of visible light,and poor selectivity of products.Although previous reviews also presented various strategies to improve photocatalytic H_(2)O_(2) production,they did not systematically elaborate the inherent relationship between the control strategies and their energy band structure.From this point of view,this article focuses on energy band engineering and reviews the latest research progress of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production.On this basis,a strategy to improve the H_(2)O_(2) production by g-C_(3)N_(4) photocatalysis is proposed through morphology control,crystallinity and defect,and doping,combined with other materials and other strategies.Finally,the challenges and prospects of industrialization of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production are discussed and envisioned.
基金supported by the National Natural Science Foundation of China (U1808205)Hebei Natural Science Foundation (F2000501005)。
文摘This paper studies the target controllability of multilayer complex networked systems,in which the nodes are highdimensional linear time invariant(LTI)dynamical systems,and the network topology is directed and weighted.The influence of inter-layer couplings on the target controllability of multi-layer networks is discussed.It is found that even if there exists a layer which is not target controllable,the entire multi-layer network can still be target controllable due to the inter-layer couplings.For the multi-layer networks with general structure,a necessary and sufficient condition for target controllability is given by establishing the relationship between uncontrollable subspace and output matrix.By the derived condition,it can be found that the system may be target controllable even if it is not state controllable.On this basis,two corollaries are derived,which clarify the relationship between target controllability,state controllability and output controllability.For the multi-layer networks where the inter-layer couplings are directed chains and directed stars,sufficient conditions for target controllability of networked systems are given,respectively.These conditions are easier to verify than the classic criterion.
基金co-supported by the National Natural Science Foundation of China(Nos.62022060,62073234,62073158,62373268,62373273)the Basic Research Project of Education Department of Liaoning Province,China(No.LJKZ0401).
文摘The helicopter Trailing-Edge Flaps(TEFs)technology is one of the recent hot topics in morphing wing research.By employing controlled deflection,TEFs can effectively reduce the vibration level of helicopters.Thus,designing specific vibration reduction control methods for the helicopters equipped with trailing-edge flaps is of significant practical value.This paper studies the optimal control problem for helicopter-vibration systems with TEFs under the framework of adaptive dynamic programming combined with Reinforcement Learning(RL).Time-delay and disturbances,caused by complexity of helicopter dynamics,inevitably deteriorate the control performance of vibration reduction.To solve this problem,a zero-sum game formulation with a linear quadratic form for reducing vibration of helicopter systems is presented with a virtual predictor.In this context,an off-policy reinforcement learning algorithm is developed to determine the optimal control policy.The algorithm utilizes only vertical vibration load data to achieve a policy that reduces vibration,attains Nash equilibrium,and addresses disturbances while compensating for time-delay without knowledge of the dynamics of the helicopter system.The effectiveness of the proposed method is demonstrated in a virtual platform.
基金Project supported by the National Natural Science Foundation of China(Nos.62273245 and 62173033)the Sichuan Science and Technology Program of China(No.2024NSFSC1486)the Opening Project of Robotic Satellite Key Laboratory of Sichuan Province of China。
文摘A distributionally robust model predictive control(DRMPC)scheme is proposed based on neural network(NN)modeling to achieve the trajectory tracking control of robot manipulators with state and control torque constraints.First,an NN is used to fit the motion data of robot manipulators for data-driven dynamic modeling,converting it into a linear prediction model through gradients.Then,by statistically analyzing the stochastic characteristics of the NN modeling errors,a distributionally robust model predictive controller is designed based on the chance constraints,and the optimization problem is transformed into a tractable quadratic programming(QP)problem under the distributionally robust optimization(DRO)framework.The recursive feasibility and convergence of the proposed algorithm are proven.Finally,the effectiveness of the proposed algorithm is verified through numerical simulation.
基金supported by Central Government to Guide local scientific and Technological Development of Hebei Province(No.216Z1902G)Major Program of National Natural Science Foundation of China(U20A20332)+1 种基金Natural Science Foundation of Hebei Province(A2022203024)Provincial Key Laboratory Performance Subsidy Project(22567612H).
文摘An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.First,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the system.Then,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.Based on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation method.According to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric constraint.Finally,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.
基金supported by the National Key Research and Development Plan,Grant/Award Number:2018YFB1503005.
文摘A modular system of cascaded converters based on model predictive control(MPC)is proposed to meet the application requirements ofmultiple voltage levels and electrical isolation in renewable energy generation systems.The system consists of a Buck/Boost+CLLLC cascaded converter as a submodule,which is combined in series and parallel on the input and output sides to achieve direct-current(DC)voltage transformation,bidirectional energy flow,and electrical isolation.The CLLLC converter operates in DC transformer mode in the submodule,while the Buck/Boost converter participates in voltage regulation.This article establishes a suitable mathematical model for the proposed system topology,and uses MPC to control the system based on this mathematical model.Module parameters are designed and calculated,and simulation is built in MATLAB/Simulink to complete the simulation comparison experiment between MPC and traditional proportional integral(PI)control.Finally,a physical experimental platform is built to complete the physical comparison experiment.The simulation and physical experimental results prove that the control accuracy and response speed ofMPC are better than traditional PI control strategy.
基金Supported by Fundamental Research Funds for the Central Universities of China (Grant No.2023JBZY020)Transformation Cultivation Program of Scientific and Technological Achievements from Beijing Jiaotong University of China (Grant No.M21ZZ200010)。
文摘As a new grinding and maintenance technology,rail belt grinding shows significant advantages in many applications The dynamic characteristics of the rail belt grinding vehicle largely determines its grinding performance and service life.In order to explore the vibration control method of the rail grinding vehicle with abrasive belt,the vibration response changes in structural optimization and lightweight design are respectively analyzed through transient response and random vibration simulations in this paper.Firstly,the transient response simulation analysis of the rail grinding vehicle with abrasive belt is carried out under operating conditions and non-operating conditions.Secondly,the vibration control of the grinding vehicle is implemented by setting vibration isolation elements,optimizing the structure,and increasing damping.Thirdly,in order to further explore the dynamic characteristics of the rail grinding vehicle,the random vibration simulation analysis of the grinding vehicle is carried out under the condition of the horizontal irregularity of the American AAR6 track.Finally,by replacing the Q235 steel frame material with 7075 aluminum alloy and LA43M magnesium alloy,both vibration control and lightweight design can be achieved simultaneously.The results of transient dynamic response analysis show that the acceleration of most positions in the two working conditions exceeds the standard value in GB/T 17426-1998 standard.By optimizing the structure of the grinding vehicle in three ways,the average vibration acceleration of the whole car is reduced by about 55.1%from 15.6 m/s^(2) to 7.0 m/s^(2).The results of random vibration analysis show that the grinding vehicle with Q235 steel frame does not meet the safety conditions of 3σ.By changing frame material,the maximum vibration stress of the vehicle can be reduced from 240.7 MPa to 160.0 MPa and the weight of the grinding vehicle is reduced by about 21.7%from 1500 kg to 1175 kg.The modal analysis results indicate that the vibration control of the grinding vehicle can be realized by optimizing the structure and replacing the materials with lower stiffness under the premise of ensuring the overall strength.The study provides the basis for the development of lightweight,diversified and efficient rail grinding equipment.
基金Key Science and Technology Projects of Jilin Province,China,Grant/Award Number:20230204081YYChangchun Science and Technology Project,Grant/Award Number:21ZY41National Natural Science Foundation of China,Grant/Award Numbers:61873304,62173048,62106023。
文摘In recent years,intelligent robots are extensively applied in the field of the industry and intelligent rehabilitation,wherein the human-robot interaction(HRI)control strategy is a momentous part that needs to be ameliorated.Specially,the efficacy and robustness of the HRI control algorithm in the presence of unknown external disturbances deserve to be addressed.To deal with these urgent issues,in this study,artificial systems,computational experiments and a parallel execution intelligent control framework are constructed for the HRI control.The upper limb-robotic exoskeleton system is re-modelled as an artificial system.Depending on surface electromyogram-based subject's active motion intention in the practical system,a non-convex function activated anti-disturbance zeroing neurodynamic(NC-ADZND)controller is devised in the artificial system for parallel interaction and HRI control with the practical system.Furthermore,the linear activation function-based zeroing neurodynamic(LAF-ZND)controller and proportionalderivative(posterior deltoid(PD))controller are presented and compared.Theoretical results substantiate the global convergence and robustness of the proposed controller in the presence of different external disturbances.In addition,the simulation results verify that the NC-ADZND controller is better than the LAF-ZND and the PD controllers in respect of convergence order and anti-disturbance characteristics.
