最新刊期
卷 53 ， 期 10 ， 2019
- 摘要：A preperception method for voluntary movement intention of lower limb using readiness potential(RP)is proposed to solve the problem of poor real-time control caused by the time lag between human movement and robot-s response in lower limb exoskeleton robot system.Firstly, the electroencephalogram(EEG)signals of motor cortex are simulated based on EEG generation mechanism of human lower limb movement and a coupled neural mass model.It is verified that the RP does exist in EEG of motor cortex during lower limb voluntary movement.Secondly, the electromyography(EMG)of lower limb is used to detect the onset time of lower limb voluntary movement, and to complete the trigger marker for voluntary movement of lower limb in EEG signals.Meanwhile, motion artifacts in EEG signals are removed by using the multivariate empirical mode decomposition(MEMD).Furthermore, RP extraction and preperception of lower limb voluntary movement intention are reali-ed by a superposed average method and a template关键词：exoskeleton robot;voluntary movement;movement intention;readiness potential;electroencephalogram362|6|4更新时间：2025-07-09
- 摘要：A segmentation algorithm for SAR images using region merging guided by morphological edge information is proposed to solve the problem that in synthetic aperture radar(SAR)image segmentation based on region merging, the over-fragmentation of initial partition affects the efficiency and quality of subsequent region merging.An anisotropic morphological directional ratio operator is constructed by using the weighted median filtering that is weighted by Gaussian Gamma function to extract the edge strength map(ESM)of an image as the strength of edge responses.Then a thresholding processing and watershed transform are performed on the ESM to obtain a high-quality initial partition.Then, the pair of adjacent regions with the smallest merging cost are iteratively merged using the technique of relative common boundary length penalty, and the final segmentation is outputted until the termination condition of region merging is satisfied.Experimental results and comparisons with methods of the sam关键词：synthetic aperture radar;image segmentation;initial partition;region merging319|5|1更新时间：2025-07-09
- 摘要：A balance control scheme of state of charge(SOC)for distributed energy storage systems is proposed to deal with the problem that inconsistencies of charge and discharge degree of lithium batteries lead to the over-charge/over-discharge of the batteries, and shorten the life of batteries in an energy storage system.A distributed energy storage structure with a single battery power module series is adopted and estimations of SOC of single lithium batteries are used as control object.An allocation formula of weighting factors is designed based on balance of SOC to adjust the charge and discharge rate of each single lithium battery dynamically and to achieve the SOC balance of the distributed energy storage system, which breaks the double-stage balance control mode in the traditional battery pack balance and eliminates the power loss caused by the energy transfer between the battery cells in the group.Moreover, the double closed-loop control of load voltage regulation and SOC balance contr关键词：distributed energy storage system;state of charge balance;weighting factor;load voltage regulation249|5|5更新时间：2025-07-09
- 摘要：A predictive control strategy of main steam temperature based on dynamic matrix control is proposed and the characteristics of large inertia, pure lag and nonlinearity of main steam temperature control for thermal power boilers are taken into account.According to the characteristics of superheated steam transmission channel, the disturbance of cooling water flow is used as feed-forward compensation.A dynamic matrix controller is designed by comprehensive consideration of disturbance factors such as unit load, fuel fluctuation and so on.The algorithm adopts a rolling optimi-ation strategy with finite time interval and introduces an error-based feedback correction algorithm so that uncertainties caused by model mismatch, time-varying and interference are comprehensively considered, and the influence caused by these factors is compensated in time, so as to improve the robustness of the system.Simulation experiments and comparisons with the conventional PID and Smith control strategies sho关键词：thermal power boiler;main steam temperature;dynamic matrix control;rolling optimi-ation253|5|6更新时间：2025-07-09
- 摘要：A spiking neural network with high precision based on a new RGB-HSV preprocessing model is proposed to solve the problem of low accuracy of spiking neural networks in the field of the classification of visual color features.The proposed network extracts cluster color features by combining the features of the simplicity of RGB color channels and intuitive of HSV color space and enhances the recognition ability.A training method with weight momentum is also proposed based on Tempotron supervised learning rules.The method updates weights with new calculations while some of last weights is retained, so that the convergence of network weights is speeded up and the simulation time is saved.Experimental results show that the classification accuracy of the proposed network is up to 96.21%, and the accuracy reaches about 84% after 6 training iterations.关键词：spiking neural networks;characteristic classification;color feature;network weight333|5|2更新时间：2025-07-09
- 摘要：A low-frequency broadband synergistic coupling mechanism of membrane-type metamaterials with high efficiency absorption is proposed to solve the problem that traditional materials are difficult to effectively control low-frequency noise.This kind of membrane-type metamaterials consists of multiple units, each unit is composed of two aluminum platelets, and each platelet is fastened on a piece of silicone membrane above an air cavity.Finite element software COMSOL Multiphysics 5.3 is used to calculate the absorption characteristics to determine the structure si-e and material parameters of the cell.Then the vibration mode and mechanism are analy-ed by two cells to solve the narrow band.The influence of typical structural parameters on synergetic coupling mechanism and absorption characteristics is discussed.The broadband sound absorption in the whole frequency range is reali-ed via synergetic coupling of multiple units.The simulations show that the absorption peaks of units can be stagg关键词：acoustic metamaterials;broadband sound absorption;synergistic coupling251|5|7更新时间：2025-07-09
- 摘要：Low frequency sound wave has strong penetrating force and difficult attenuation in the propagation process.A new acoustic black hole superstructure is investigated.Multiple acoustic black hole units are embedded in an array on a 10 mm thin plate.The designed superstructure of acoustic black hole is produced by 3D printing technology, and the acoustic characteristics of the superstructure are verified by standing wave tube experiment.According to the analysis of experimental data, the acoustic black hole superstructure can achieve an average sound insulation of nearly 30 dB in the frequency band of 50-1 600 H-, and an average sound insulation of up to 40 dB in the frequency band of 100-600 H-.When the power exponent of the geometric shape power function of the acoustic black hole element changes, the sound insulation of the acoustic black hole superstructure is also discussed.Because the designed superstructure of acoustic black hole requires high processing technology and is not conven关键词：acoustic black hole;acoustic superstructure;low frequency broadband353|6|10更新时间：2025-07-09
- 摘要：Aiming at the difficulty in detecting the machining error of free-form surface blade, a method for evaluating the machining error of free-form surfaces is proposed, where the point cloud is obtained by the high-precision blue-light scanner as the measured data, and the STL model of the free-form surface is taken as the theoretical one.The dynamic deviation threshold is set to remove the far outliers of point cloud, and the near outliers of the point cloud are removed with the SVLOF method.Then the iterative closest points algorithm is used to separate the rotation of the point cloud position error, and the adaptive particle swarm algorithm is used to separate the translation amount according to the minimum region principle.The deviation between the point cloud and the model is calculated after the reference transformation of the point cloud.The experimental results show that the root mean square error of the position error vector evaluated with the proposed method is reduced by 66% and关键词：point cloudy data;free-form surface;machining error;iterative closest point algorithm;particle swarm optimi-ation294|6|3更新时间：2025-07-09
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A Recognition Method of Spread and Grasp Actions Combining Motion Imagination and Action Observation
摘要：A recognition method for spread and grasp actions of a hand that combines motion imagination and action observation is proposed to obtain electroencephalogram(EEG)feature that is directly relevant to motor imagery of spread and grasp movements of the hand and to effectively identify fine actions.First, a compound paradigm that combines motor imagery and action observation(short for compound paradigm)is designed to enhance activation of the human cerebral cortex associated with the spread and grasp actions of a hand.Activation rules of the cerebral cortex are investigated under motor imagery, action observation and compound paradigm.Then, EEG is reconstructed for each channel by using a wavelet reconstruction and the multiscale entropy of EEG is calculated.EEG features of spread and grasp actions of the hand are extracted through a common spatial pattern.Finally, both the -spread- and -grasp- actions are identified from EEG features based on a linear discriminant method.Experimental关键词：electroencephalogram;motion imagination;action observation;spread and grasp action333|5|1更新时间：2025-07-09
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