Components of power systems essentially belong to a special class of nonlinear differential-algebraic equations subsystem, whose index is one and interconnection is locally measurable. In this paper, the decentralized...
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Tracking law designed for future Mars entry missions is investigated in this article. For precision landing, the nonlinear entry dynamics, complex uncertainties and input saturation constraints are unavoidable problem...
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Tracking law designed for future Mars entry missions is investigated in this article. For precision landing, the nonlinear entry dynamics, complex uncertainties and input saturation constraints are unavoidable problems. Facing these challenges, the Mars entry trajectory tracking scheme via constrained multi-model predictive control (CMPC) is employed. The CMPC is made up of some constrained predictive control (CPC) in different time domain during the Mars entry mission. Each constrained predictive controller consists of a linearized prediction model (obtained by linearizing at different operating point), feedback correction for active model mismatch rejection caused by the complex uncertainties, and constrained rolling optimization for a smooth control input under a saturation constraint. Monte Carlo simulations demonstrate the effectiveness and excellence of the proposed method under the saturation constraint of input and uncertainties of initial state and aerodynamic parameters such as atmospheric density, ballistic coefficient and lift-to-drag ratio.
Safe moving is a basic ability for a mobile robot, and it is beneficial for the robot to avoid the collisions with the environment if it knows the boundaries between the obstacles and free space. In this paper, a cont...
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Understanding the strategies to optimize/suppress information spreads under intense competition could provide important insights in a broad range of settings including viral marketing,emergency response and informatio...
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Understanding the strategies to optimize/suppress information spreads under intense competition could provide important insights in a broad range of settings including viral marketing,emergency response and information system ***,most of existing studies about competitive influence diffusion mainly focus on two-information competition *** date,the competitive influence maximization problem considering the mechanism of multi-information competition is still not well *** this paper,we conducted computational experiments to study the competitive influence maximization with multi-information competition *** applying an information diffusion model called limited attention model(LAM),we carried on two computational experiments to validate the model and investigate the relation between seed selection methods and the properties of information *** experimental results show that 1)the LAM model could reproduce the features of empirical distribution in Chinese social media;2)the eigenvector centrality-based heuristic is a reasonable seed selection method for competitive influence maximization *** results of this paper can provide significant potential implications for information system design and management.
In this paper, aiming at the indoor scene under monitoring by visual sensor network (VSN), an object recognition approach based on structural feature is presented. Firstly, we regard the output of existing line segmen...
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In this paper, aiming at the indoor scene under monitoring by visual sensor network (VSN), an object recognition approach based on structural feature is presented. Firstly, we regard the output of existing line segment detector LSD with proper parameters as the preliminary extraction result and it still will be further restored and split. Then, we give an inference model based on structural features of object including line segment ontology characteristics and relative relationship between the line segments. Finally, the objects are recognized with position information through inference. The effectiveness of the approach is verified, and the results show that our approach does not rely on segmentation and has robustness on partial defect and structural deformation to some extent.
Mud pulse signal extracting in Wireless measure while drilling (MWD) was a core technology in the process of oil drilling development. Whether the resolution of detected mud pulse signal start point location is accura...
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Despite the experimental observation of shear-thinning rheological behavior depending on the nanoparticle volume fraction, nanofluids were treated as either Newtonian or viscoelastic fluids in previous studies on ther...
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Despite the experimental observation of shear-thinning rheological behavior depending on the nanoparticle volume fraction, nanofluids were treated as either Newtonian or viscoelastic fluids in previous studies on thermal convection. In this work, taking into account the shear-thinning rheology, Brownian diffusion and thermophoresis of nanofluids, the onset of thermal convection in a nonhomogeneous nanofluid-saturated porous layer with throughflow is investigated. The power-law model is adopted to describe the shear-thinning behavior of nanofluids. The combined effects of Lewis number, Péclet number and power-law index on the thermal instability are analyzed. It is found that the most unstable perturbations are transverse rolls, and both traveling-wave and oscillatory modes may occur. The critical Rayleigh number can be significantly reduced or increased with the increasing power-law index, mainly depending on the value of Péclet number. Furthermore, the decrease of Lewis number can promote or suppress the onset of thermal convection, depending on whether the nanoparticle distribution at the basic state is bottom-heavy or top-heavy.
A compound-structure permanent-magnet synchronous machine (CS-PMSM), which integrates two PMSMs, is a hybrid electric vehicle (HEV) power train concept. In order to meet the requirement of wide speed range of HEV, an ...
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ISBN:
(纸本)9781479951635
A compound-structure permanent-magnet synchronous machine (CS-PMSM), which integrates two PMSMs, is a hybrid electric vehicle (HEV) power train concept. In order to meet the requirement of wide speed range of HEV, an axialaxial flux CS-PMSM with a new mechanical method of varying air gap to fulfill field-weakening control and to improve the operating speed range is investigated. The field-weakening principle of the axial-axial flux CS-PMSM with varying air gap is analyzed. The electromagnetic performances with air gaps varying are evaluated by 3D finite-element method (FEM). The principle of selecting original air gap is proposed with comprehensive consideration. The field weakening capability by varying air gap is evaluated based on the comparison with two other electric methods.
According to the actual circumstance of the intersection,reasonably adjusting traffic light time can help to ease traffic pressure and save transportation *** this paper,Interval type-2 fuzzy sets and matched-degree a...
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According to the actual circumstance of the intersection,reasonably adjusting traffic light time can help to ease traffic pressure and save transportation *** this paper,Interval type-2 fuzzy sets and matched-degree are applied to the time of intersection signal adjusting,and five words are used to cover the range of adjusting lights’time,finally according to the average number of stranded vehicles,a query table is built to inquire and control the signal time during a certain period.
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