For spacecraft formation flight,the information of relative motion reachable set is very important,which can be used to predict the operating boundary of adjacent spacecraft and thus to ensure the safety of spacecraft...
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For spacecraft formation flight,the information of relative motion reachable set is very important,which can be used to predict the operating boundary of adjacent spacecraft and thus to ensure the safety of spacecraft *** this paper,we aim at developing a numerical method to approximate the reachable set for spacecraft relative *** particular,we focus on the quality of the approximation and the computational *** on the bang-bang control principle,a polyhedral approximation algorithm is proposed to compute the reachable set of a relative motion spacecraft *** inner approximation and an outer approximation of the reachable set for the system can be *** prove that the approximation quality measured in Hausdorff distance can be *** method is easy to implement and has low computational ***,the effectiveness of the algorithm is demonstrated by experimental simulation.
This paper investigates a finite-time tracking problem for the uncertainty nonlinear systems in nonstrict-feedback form,in which the output signal is restricted in a *** on the barrier Lyapunov function and dynamic su...
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This paper investigates a finite-time tracking problem for the uncertainty nonlinear systems in nonstrict-feedback form,in which the output signal is restricted in a *** on the barrier Lyapunov function and dynamic surface control scheme,a novel adaptive neural controller is proposed by using the finite-time Lyapunov *** the aforementioned literature on finite time tracking control,the violation of system output constraint is avoided by combining the barrier Lyapunov function method with finite-time *** structural characteristics of neural network is introduced to expand the adaptive neural finite-time backstepping method to the uncertainty nonlinear systems in the non-strict ***,the dynamic surface control is introduced to cope with the problem of“explosion of complexity”inherent in conventional backstepping *** is shown that the designed controller can achieve finite-time tracking control and all the variables in the closed-loop system are bounded with output constraint guaranteed form stability analysis and simulation results.
Increasing renewable energy integration in power systems is an important way of decarbonising carbon emissions. Recently, the ever-increasing deployment of distributed generation (DG) is considered effective in reduci...
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This study focuses on enhancing the evasion capabilities of unmanned ground vehicles(UGVs) using Generative Adversarial Imitation Learning(GAIL). The UGVs are trained to evade unmanned aerial vehicles(UAVs). A decisio...
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This study focuses on enhancing the evasion capabilities of unmanned ground vehicles(UGVs) using Generative Adversarial Imitation Learning(GAIL). The UGVs are trained to evade unmanned aerial vehicles(UAVs). A decision-making neural network has been trained via GAIL to refine evasion strategies with expert demonstrations. The simulation environment was developed with OpenAI Gym and calibrated with real-world data for the improvement of accuracy. The integrated platform including the proposed algorithm was tested in flight experiments. Results showed that the UGVs could effectively evade UAVs in the complex and dynamic environment.
The complexity of aeroengine external piping systems necessitates the implementation of automated design processes to reduce the duration of the design ***,existing routing algorithms often fail to meet designer requi...
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The complexity of aeroengine external piping systems necessitates the implementation of automated design processes to reduce the duration of the design ***,existing routing algorithms often fail to meet designer requirements because of the limitations in providing a single solution and the inadequate consideration for route *** this study,we propose the multi-solution pipe-routing method for *** method utilizes a hybrid encoding approach by incorporating fixed-length encoding to represent route constraints and variable-length encoding and indicate free-exploration *** approach enables designers to specify route constraints and iterate over the appropriate number of control points by employing a modified genetic iteration mechanism for variable-length ***,we employ a pipe-shaped clustering niche method to enhance result *** practicability of the newly proposed method is confirmed through comparative experiments and simulations based on the“AeroPiping”system developed on Siemens *** solutions demonstrate significant differences in circumferential and axial orientations while still satisfying engineering constraints.
Owing to the greater integration capability, flexible multilayer foil (FMLF) technique has a great potential to promote the evolution of passive integration techniques. To understand the mechanism of this technique is...
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With the rapid development of the world economy,IGBT has been widely used in motor drive and electric energy *** order to timely detect the fatigue damage of IGBT,it is necessary to monitor the junction temperature of...
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With the rapid development of the world economy,IGBT has been widely used in motor drive and electric energy *** order to timely detect the fatigue damage of IGBT,it is necessary to monitor the junction temperature of *** order to realize the fast calculation of IGBT junction temperature,a finite element method of IGBT temperature field reduction is proposed in this ***,the finite element calculation process of IGBT temperature field is introduced and the linear equations of finite element calculation of temperature field are *** field data of different working conditions are obtained by finite element simulation to form the sample *** the covariance matrix of the sample space is constructed,whose proper orthogonal decomposition and modal extraction are carried *** basis vector space is selected to complete the low dimensional expression of temperature vector inside and outside the sample ***,the reduced-order model of temperature field finite element is obtained and *** results of the reduced order model are compared with those of the finite element method,and the performance of the reduced-order model is evaluated from two aspects of accuracy and rapidity.
Magnetic levitation is a non-self-stabilizing system that requires high control *** system's stability is affected by the mechanical interface between the levitation object and the loading device,with self-excited...
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Magnetic levitation is a non-self-stabilizing system that requires high control *** system's stability is affected by the mechanical interface between the levitation object and the loading device,with self-excited vibration generated in the operation *** paper proposes to consider the mechanical behavior of the contact interface in the magnetic levitation *** electromagnetic and control systems are mechanically equivalent,the coupled electric-magnetic-mechanical model is established by adopting the lumped mechanical modeling ***,the effect of the contact clearance on the mechanical behavior of the system is analyzed using the Routh-Hurwitz *** research results show that with the decrease in the contact clearance,the vibration frequency *** the vibration frequency exceeds the critical value,a continuous vibration phenomenon occurs in the system under the joint action of feedback and energy ***,the effect of interface parameters on the vibration characteristics is analyzed using the fourth-order Runge-kutta numerical *** analyses show that the interface contact leads to combination frequency and frequency multiplication components in the coupled system.
Aiming at the problem that the intermediate potential part of the traditional bistable stochastic resonance model cannot be adjusted independently, a new composite stochastic resonance(NCSR) model is proposed by combi...
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Aiming at the problem that the intermediate potential part of the traditional bistable stochastic resonance model cannot be adjusted independently, a new composite stochastic resonance(NCSR) model is proposed by combining the Woods–Saxon(WS) model and the improved piecewise bistable model. The model retains the characteristics of the independent parameters of WS model and the improved piecewise model has no output saturation, all the parameters in the new model have no coupling characteristics. Under α stable noise environment, the new model is used to detect periodic signal and aperiodic signal, the detection results indicate that the new model has higher noise utilization and better detection ***, the new model is applied to image denoising, the results showed that under the same conditions, the output peak signal-to-noise ratio(PSNR) and the correlation number of NCSR method is higher than that of other commonly used linear denoising methods and improved piecewise SR methods, the effectiveness of the new model is verified.
The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are *** effects of the control and interface parameters on the system's stability are *** frequency ...
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The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are *** effects of the control and interface parameters on the system's stability are *** frequency range of self-excited vibrations is investigated from the energy point of *** phenomenon of self-excited vibrations is elaborated with the phase *** corresponding control strategies are briefly analyzed with respect to the vibration *** results show that when the levitation objects collide with the mechanical interface,the system's vibration frequency becomes larger with the decrease in the collision gap;when the vibration frequency exceeds the critical frequency,the electromagnetic system continues to provide energy to the system,and the collision interface continuously dissipates energy so that the system enters the self-excited vibration state.
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