Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes *** remaining permanently in a singularity are beneficial for linearto-r...
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Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes *** remaining permanently in a singularity are beneficial for linearto-rotary motion ***-Duffy(GD)platform is a mobile structure admitting a Bricard *** this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed *** generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same *** to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD ***,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis.
Accurate channel estimation ensures auto-pilot safety in 5G and 6G communications. Nevertheless, multiuser massive MIMO systems with one-bit ADCs significantly decrease accuracy due to information loss during quantiza...
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The selective attenuation and scattering of light in underwater environments cause color distortion and contrast reduction in underwater images,which can impede the ever-growing demand for underwater robot *** address...
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The selective attenuation and scattering of light in underwater environments cause color distortion and contrast reduction in underwater images,which can impede the ever-growing demand for underwater robot *** address these issues,we propose a Multi-Color space Residual Network(MCRNet)for underwater image *** method takes advantage of the unique features of color representation in the RGB,HSV,and Lab color *** utilizing the distinct feature representations of images in different color spaces,we can highlight and fuse the most informative features of the three color *** approach employs a self-attention mechanism in the multi-color space feature fusion *** experiments demonstrate that our method achieves satisfactory results in color correction and contrast improvement of underwater images,particularly in severely degraded ***,our method outperforms state-of-the-art methods in both subjective visual comparison and objective evaluation metrics.
In high-power motor drive systems, the two-unit permanent magnet synchronous motor (PMSM) system driven by parallel inverters controlled by pulse width modulation (PWM) will generate significant common mode voltage (C...
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The gradual penetration of grid-forming(GFM)converters into new power systems with renewable energy sources may result in the emergence of small-signal instability *** issues can be elucidated using sequence impedance...
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The gradual penetration of grid-forming(GFM)converters into new power systems with renewable energy sources may result in the emergence of small-signal instability *** issues can be elucidated using sequence impedance models,which offer a more tangible and meaningful interpretation than dq-domain impedance models and state-space ***,existing research has primarily focused on the impact of power loops and inner control loops in GFM converters,which has not yet elucidated the precise physical interpretation of inner voltage and current loops of GFM converters in *** paper derives series-parallel sequence impedance models of multi-loop GFM converters,demonstrating that the voltage loop can be regarded as a parallel impedance and the current loop as a series ***,the corresponding small-signal stability characteristics can be identified through Bode diagrams of sequence impedances or by examining the physical meanings of impedances in series and in *** results indicate that the GFM converter with a single power loop is a candidate suitable for application in new power systems,given its reduced number of control parameters and enhanced low-frequency performance,particularly in weak *** results of PLECS simulations and corresponding prototype experiments verify the accuracy of the analytical analysis under diverse grid conditions.
The primary factor contributing to frequency instability in microgrids is the inherent intermittency of renewable energy *** paper introduces novel dual-backup controllers utilizing advanced fractional order proportio...
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The primary factor contributing to frequency instability in microgrids is the inherent intermittency of renewable energy *** paper introduces novel dual-backup controllers utilizing advanced fractional order proportional integral derivative(FOPID)controllers to enhance frequency and tie-line power stability in microgrids amid increasing renewable energy *** improve load frequency control,the proposed controllers are applied to a two-area interconnectedmicrogrid system incorporating diverse energy sources,such as wind turbines,photovoltaic cells,diesel generators,and various storage technologies.A novelmeta-heuristic algorithm is adopted to select the optimal parameters of the proposed *** efficacy of the advanced FOPID controllers is demonstrated through comparative analyses against traditional proportional integral derivative(PID)and FOPID controllers,showcasing superior performance inmanaging *** optimization algorithm is also evaluated against other artificial intelligent methods for parameter optimization,affirming the proposed solution’s *** robustness of the intelligent controllers against system uncertainties is further validated under extensive power disturbances,proving their capability to maintain grid *** dual-controller configuration ensures redundancy,allowing them to operate as mutual backups,enhancing system *** research underlines the importance of sophisticated control strategies for future-proofing microgrid operations against the backdrop of evolving energy landscapes.
Using an islanded microgrid(MG)with large-scale integration of renewable energy is the most popular way of solving the reliable power supply problem for remote areas and critical electrical ***,compared with tradition...
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Using an islanded microgrid(MG)with large-scale integration of renewable energy is the most popular way of solving the reliable power supply problem for remote areas and critical electrical ***,compared with traditional power systems,the limited spinning reserves and network communication bandwidth may cause weak frequency stability in the presence of stochastic renewable active outputs and load demand *** this paper,an adap-tive event-triggered control(ETC)strategy for a load frequency control(LFC)system in an islanded MG is ***,a bounded adaptive event-triggered communication scheme is *** not only saves on network resources,but also ensures that the control center has a sensitive monitoring ability for the MG operating status when the frequency deviations have been effectively ***,by fully considering the spinning reserve con-straints and uncertain communication delays,the LFC system is described as a nonlinear model with saturation *** criteria for ETC parameters are strictly deduced based on Lyapunov stability ***,an ETC parameter optimization algorithm based on random direction search is developed to reconcile the bandwidth occupancy and control *** effectiveness of the proposed method is verified in an MG test system.
A three-dimensional (3-D) analytical model with a high computational efficiency is proposed for a surface-inset axial flux machine (SIAFM). Accounting for the air-gap fringing field, the proposed 3-D analytical model ...
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To address the challenges of high computational costs, large storage demands, and low detection accuracy in internal rail damage identification, we propose a lightweight detection model, GhostMicroNet-YOLOv8n, as an e...
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In this paper,an improved spatio-temporal alignment measurement method is presented to address the inertial matching measurement of hull deformation under the coexistence of time delay and large misalignment *** misal...
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In this paper,an improved spatio-temporal alignment measurement method is presented to address the inertial matching measurement of hull deformation under the coexistence of time delay and large misalignment *** misalignment angle and time delay often occur simultaneously and bring great challenges to the accurate measurement of hull deformation in space and *** proposed method utilizes coarse alignment with large misalignment angle and time delay estimation of inertial measurement unit modeling to establish a brand-new spatiotemporal aligned hull deformation measurement *** addition,two-step loop control is designed to ensure the accurate description of dynamic deformation angle and static deformation angle by the time-space alignment method of hull *** experiments illustrate that the proposed method can effectively measure the hull deformation angle when time delay and large misalignment angle coexist.
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