Table of Content

28 May 2023, Volume 57 Issue 5 Previous Issue    Next Issue

New Type Power System and the Integrated Energy

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A Short-Term Production Simulation Model of Wind-PV-Hydrogen-Pumped Storage Zero Carbon Power System GU Huijie, PENG Chaoyi, SUN Shuhao, LIU Mingtao, XIE Jun, SHI Xionghua, BAO Yong 2023, 57 (5):  505-512.  doi: 10.16183/j.cnki.jsjtu.2022.054 Abstract ( 490 )   HTML ( 208 )   PDF (1646KB) ( 413 )   Save To achieve the goal of carbon peaking and carbon neutrality, it is urgent to build a new power system with renewable energy as the main body, characterized by clean energy supply and electrification of energy consumption. Considering the intermittency and randomness of wind-solar power, as well as the energy storage and flexibility of pumped storage power stations and power-to-hydrogen, a short-term production simulation model of wind-PV-hydrogen-pumped storage zero carbon power system is established based on the stochastic programming theory. In the proposed short-term production simulation model, on the basis of meeting the total demand of flexible hydrogen load, the short-term production simulation is implemented, including electricity-hydrogen production schedule, reserve capacity, pumped storage-water discharge power output and wind-solar curtailment, with the goal of maximizing green on-grid electricity. Taking Zhangbei zero carbon power system of China as an example, many operation scenarios are established to simulate the proposed model. The simulation results show that the proposed model can effectively simulate the on-grid scheme situation of green power in which the system deals with the randomness of wind-solar output in any output scenarios of wind-solar power scene set. The flexible hydrogen load and the pumped storage power station can effectively promote wind-solar energy accommodation and increase the comprehensive benefit of the combined system. Figures and Tables | References | Related Articles | Metrics

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Load Transfer Flexibility Analysis of Distribution Network with Electric Energy Routers ZHANG Peng, LÜ Gongxiang, LIU Zhijie, ZHU Shouzhen, SHAO Zhiyong 2023, 57 (5):  513-520.  doi: 10.16183/j.cnki.jsjtu.2021.541 Abstract ( 261 )   HTML ( 175 )   PDF (1327KB) ( 287 )   Save With the increase of the penetration rate of distributed generation (DG), lack of flexibility of distribution network has become increasingly prominent. This paper focuses on electric energy router (EER), and analyzes its impact on the flexibility of distribution network. First, the index of the transfer flexibility of distribution network is proposed to represent one aspect of distribution network flexibility. Then, the linear model of the EER and its related constraints are analyzed, and an optimization model of the transfer flexibility of the active distribution network with the EER model is constructed. Finally, based on the 94-bus alternating current distribution network, different scenarios are designed to analyze and compare the effects of different DG operation control modes and different parameters of EER on the transfer flexibility of distribution network. The effectiveness of EER in improving the transfer flexibility of distribution network is verified. Figures and Tables | References | Related Articles | Metrics

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Minimum Return Power Control for Three-Level Dual Active Hybrid Full-Bridge DC-DC Converters TAO Haijun, ZHANG Jinsheng, XIAO Qunxing, ZHENG Zheng 2023, 57 (5):  521-532.  doi: 10.16183/j.cnki.jsjtu.2021.493 Abstract ( 315 )   HTML ( 179 )   PDF (5890KB) ( 218 )   Save Hybrid three-level full bridge (H-TLFB) DC-DC converters increase the input voltage range by introducing a three-level bridge arm. Aimed at the problems of large power return and high current stress in the traditional dual phase shift control, a minimum return power control strategy is proposed. First, the power transmission characteristics of H-TLFB DC-DC converter are analyzed, the size of the return power value of the converter in two different operating modes is compared, and the optimal shift of the return power is calculated according to the mathematical relationship between the return power and the voltage ratio, the shift and the transmission power. The corresponding optimal shift of the return power is calculated, and the corresponding optimization control strategy is designed. Compared with the traditional dual phase shift control strategy, the return power in the minimum return power control strategy can reach the minimum value in the full power transmission range, and within a certain voltage ratio range, the return power and current stress can be optimized at the same time. Finally, the correctness and feasibility of the design control strategy are verified by experiments. Figures and Tables | References | Related Articles | Metrics

Biomedical Engineering

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Segmentation and Evaluation of Continuous Rehabilitation Exercises HU Mingxuan, QIAO Jun, ZHANG Zhinan 2023, 57 (5):  533-544.  doi: 10.16183/j.cnki.jsjtu.2021.458 Abstract ( 359 )   HTML ( 15 )   PDF (17320KB) ( 284 )   Save To provide an accurate and objective feedback on rehabilitation training movements and to improve the motivation of rehabilitation patients in rehabilitation training, a motion evaluation method capable of processing continuous human rehabilitation training movement data is proposed. First, a motion segmentation method based on the Gaussian mixture model (GMM) is developed to extract single motion repetition from continuous repetitive motion sequences of the same motion. Then, based on relevant a priori knowledge, a multi-feature fusion motion evaluation method combining significant motion feature dynamic time warping (DTW) distance evluation and Gaussian mixture model likelihood evaluation is proposed to perform motion evaluation in both the overall motion feature and local joint information of rehabilitation exercises. The results show that the motion segmentation method can segment the motion data of continuous repetitive motions well, and the correct rate of segmented motions on the dataset reaches more than 95%. The multi-feature fusion motion evaluation method effectively improves the differentiation of motion evaluation between healthy samples and rehabilitation patient samples, so that the motion scores of healthy samples are mainly distributed in the range of 0.93—0.94 on a scale of 0—1, while the motion scores of patient samples are mainly distributed in the range of 0.81—0.89. Figures and Tables | References | Related Articles | Metrics

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Characteristics of a Hybrid Three-Dimensional Transmitting Coil for Wireless Power Transmission of Intestinal Robot ZHUANG Haoyu, YAN Guozheng, FEI Qian, WANG Wei, ZHAO Kai 2023, 57 (5):  545-551.  doi: 10.16183/j.cnki.jsjtu.2021.356 Abstract ( 272 )   HTML ( 14 )   PDF (6114KB) ( 255 )   Save In order to meet the needs of the intestinal robot to obtain power stably through wireless methods in different positions and postures, and to reduce the volume of the intestinal robot as much as possible, the transmitting coil is required to have the ability to generate spatial multi-dimensional magnetic fields. A hybrid transmitting coil structure is proposed, which combines Helmholtz coil pair and saddle-shaped coil pair. The structure is compact, and its symmetry can be used to generate a three-dimensional magnetic field without dead zone through rotation. The characteristics of the two types of coils and the combined characteristics are analyzed separately. The simulation and experimental results show that at the excitation of 2 A current, the minimum transmission efficiency of 3.44% and the received power of 1 204 mW can be obtained at the center of the coil. The minimum positional uniformity is 88.1%, and the three-dimensional power coverage can be achieved. Figures and Tables | References | Related Articles | Metrics

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Real-Time Laser Speckle Imaging of Blood Flow with High Gray Level and High Resolution ZHANG Zelong, ZHANG Yingchao, WU Bo, DONG Wei, FAN Youben 2023, 57 (5):  552-559.  doi: 10.16183/j.cnki.jsjtu.2021.466 Abstract ( 336 )   HTML ( 15 )   PDF (27048KB) ( 320 )   Save Laser speckle contrast imaging (LSCI) is a large measurement ranging, real-time, high spatial resolution optical imaging method. Exisiting reserches show that the low gray level (8-bit) and low resolution (752×480 pixels) camera can effectively monitor the flow of scattering media such as blood, but the defects such as large noise of scattered particles and small effective imaging area are difficult to be compensated by software, which seriously affects the imaging quality. Monitoring blood flow with a camera with a high gray level (16-bit) and a high resolution (2 048×2 048 pixels) will slow down the imaging speed of a single frame, and parallel computing can reduce the image processing time by 1/3. With the aid of an animal blood flow experiment, the results of high-gray-level and high-resolution spatial laser speckle contrast imaging (sLSCI), spatial approximate laser speckle contrast imaging (sLSCIa), and temporal laser speckle contrast imaging (tLSCI) were compared and analyzed using imaging speed and imaging quality as evaluation criteria. The parallel computation of high-gray-level and high-resolution sLSCI takes into consideration both imaging quality and imaging speed, which can meet the requirements of clinical real-time monitoring of blood flow. Figures and Tables | References | Related Articles | Metrics

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Finite Element Analysis of Decompression Effect of Custom Additively Manufactured Knee Orthosis Compartments XU Yuanjing, GAO Haifeng, WU Yuncheng, LIU Yihao, ZHANG Ziyan, HUANG Chenglan, WANG Zanbo, LIU Tongyou, WANG Caiping, MIAO Weiqiang, WANG Jinwu 2023, 57 (5):  560-569.  doi: 10.16183/j.cnki.jsjtu.2022.194 Abstract ( 451 )   HTML ( 16 )   PDF (7360KB) ( 192 )   Save To simulate the biomechanical changes of knee joint before and after wearing the orthosis in patients with knee osteoarthritis (KOA) by constructing a finite element model of the knee joint and a customized additively manufactured knee orthosis, so as to verify the decompression effect of the orthosis, and aimed at orthopaedics, a quantitative research on the therapeutic effect of knee orthosis was conducted to evaluate the clinical efficacy of knee orthosis.This experiment was approved by the Ethics Committee of the Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. A woman with knee osteoarthritis was recruited, and the knee joint was subjected to optical body surface and CT scans. A custom-made additively manufactured knee orthosis was designed according to the principle of unilateral decompression. After boundary setting and other steps, software such as ANSYS was used to build a finite element model of the knee joint and a customized additively manufactured knee joint orthosis. By applying a compressive load of 1100 N to the knee joint along the direction of the lower limb load-bearing axis, a simulation and stress analysis was performed to study the deloading effect of a custom additively manufactured knee orthosis on the knee compartment. A finite element analysis of KOA characteristics was conducted for verification, considering the influence of cartilage, ligament, and lower limb skin on the bearing capacity of the knee joint. Compared with the case without wearing any orthosis, after wearing the customized knee orthosis, the varus angle of the knee joint was reduced, the medial pressure of the knee joint was shifted to the lateral side, and the pressure of the medial compartment of the knee joint was significantly reduced. The custom additively manufactured knee orthosis can reduce the pressure generated by the medial compartment of the knee joint during walking in patients with early and mid-stage medial compartment knee osteoarthritis, and the load reduction effect is significant. Figures and Tables | References | Related Articles | Metrics

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UConvTrans:A Dual-Flow Cardiac Image Segmentation Network by Global and Local Information Integration LI Qing, HUANGFU Yubin, LI Jiangyun, YANG Zhifang, CHEN Peng, WANG Zihan 2023, 57 (5):  570-581.  doi: 10.16183/j.cnki.jsjtu.2022.088 Abstract ( 799 )   HTML ( 45 )   PDF (9362KB) ( 741 )   Save Cardiac magnetic resonance image (MRI) segmentation has the features such as there is a lot of noise, the target areas are indistinguishable from the background, and the shape of the right ventricle is irregular. Although convolution operations are good at extracting local features, the U-shaped convolutional neural networks (CNN) structure hardly models long-distance dependency between pixels and can not achieve ideal segmentation results on cardiac MRI. To solve these problems, UConvTrans is proposed with a dual-flow U-shaped network by global and local information integration. First, the network applies the CNN branch to extract local features and capture global representations by Transformer branch, which retains local detailed features and suppresses the interference of noise and background features in cardiac MRI. Next, the bidirectional fusion module is proposed to fuse the features extracted by CNN and the Transformer with each other, enhancing the feature expression capability and improving the segmentation accuracy of the right ventricle. Besides, the parameters of network can be set flexibly because the transformer structure in the proposed method does not require pre-trained weights. The proposed method also strikes a better balance between precision and efficiency, which is evaluated on the MICCAI 2017 ACDC dataset. The results show that the network outperforms U-Net by 1.13% average dice coefficient while the parameter amount and the floating point operations are only 10% and 8% of the U-Net. Finally, the proposed method achieves a dice coefficient of 92.42% for the right ventricle, 91.64% for the myocardium, and 95.06% for the left ventricle respectively and wins the first place in the myocardium and left ventricle on test set. Figures and Tables | References | Related Articles | Metrics

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Fast Parallel Imaging Reconstruction Method Based on SIDWT and Iterative Self-Consistency DUAN Jizhong, QIAN Qingqing 2023, 57 (5):  582-592.  doi: 10.16183/j.cnki.jsjtu.2022.236 Abstract ( 245 )   HTML ( 17 )   PDF (7918KB) ( 273 )   Save To improve the reconstruction speed of parallel magnetic resonance imaging, an efficient reconstruction method named fSIDWT-SPIRiT is proposed based on shift-invariant discrete wavelets transform (SIDWT) and the iterative self-consistent parallel imaging reconstruction (SPIRiT) model. This method addresses the complex optimization problem containing data consistency term, calibration consistency term, and L1-norm regularization term. First, data consistency term and calibration consistency term are combined and processed, and then solved by a projected fast iterative shrinkage-thresholding algorithm to achieve fast parallel MRI reconstruction. Finally, simulation experiments are conducted using different human organ datasets. The results show that the proposed method is able to guarantee the image reconstruction quality with a faster convergence speed compared with other methods. Figures and Tables | References | Related Articles | Metrics

Electronic Information and Electrical Engineering

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Decoupling and Synchronization Control of Asymmetric Flexure-Linked Dual-Drive Gantry Stage WEI Guangyu, GU Chaochen, YANG Shusheng, GUAN Xinping 2023, 57 (5):  593-600.  doi: 10.16183/j.cnki.jsjtu.2021.456 Abstract ( 526 )   HTML ( 22 )   PDF (5432KB) ( 531 )   Save A decoupling and synchronization control strategy based on a model-compensated extended state observer is proposed in control of a dual-drive gantry positioning stage with asymmetric flexure-linked structures. A gantry dynamic model considering the features of the flexure-linked structures and the impact of load acceleration is built using Lagrangian equations. Translational and rotational control loops are designed according to this model, while extended state observers with compensation of known coupling items in the model are deployed in each control loop to estimate and attenuate the total disturbances composed of unmodeled dynamics, unknown couplings, etc. The experimental results show that the proposed control strategy, which is simple to realize and requires few parameters to be measured, can effectively decouple the dynamics of dual axes and attenuates disturbances, greatly improving the dynamic response and synchronization accuracy of the gantry stage. Figures and Tables | References | Related Articles | Metrics

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Coupling Modeling of Humanoid Flexible Joint and Vibration Suppression at Variable Load SONG Chuanming, DU Qinjun, LI Cunhe, LUO Yonggang 2023, 57 (5):  601-612.  doi: 10.16183/j.cnki.jsjtu.2021.342 Abstract ( 247 )   HTML ( 13 )   PDF (5177KB) ( 383 )   Save Aimed at the joint vibration problem caused by the load change of humanoid flexible joint, a torque compensation control method based on state observer is proposed. By controlling the motor to output a torque increment equivalent to the disturbance torque, the joint torque can quickly balance the load torque and shorten the oscillation process of the elastic element passively adapting to the load change. A state observer for estimating load disturbance torque and motor speed is designed, whose convergence is proved by the Lyapunov function. The control structure of the drive system based on the proportional integral-intergral proportional (PI-IP) speed regulator is established, and the observer output feedforward link is added to the speed regulator to improve the anti-interference ability of the system. The simulation results show that compared with proportional integral differential (PID) control and joint force feedback proportional differential (PD) control, the proposed method can restore the motor speed to stability within 0.6 s after load change and realize joint vibration suppression within 1 s. Besides, the joint speed adjustment time is shortened by about 1.8 s and 0.9 s respectively, which effectively improves the dynamic adjustment ability of the system. Finally, the effectiveness of the proposed method was verified by experiments on an integrated flexible joint testing platform. Figures and Tables | References | Related Articles | Metrics

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A Single Image Deraining Algorithm Based on Swin Transformer GAO Tao, WEN Yuanbo, CHEN Ting, ZHANG Jing 2023, 57 (5):  613-623.  doi: 10.16183/j.cnki.jsjtu.2022.032 Abstract ( 505 )   HTML ( 41 )   PDF (26863KB) ( 432 )   Save Single image deraining aims to recover the rain-free image from rainy image. Most existing deraining methods based on deep learning do not utilize the global information of rainy image effectively, which makes them lose much detailed and structural information after processing. Focusing on this issue, this paper proposes a single image deraining algorithm based on Swin Transformer. The network mainly includes a shallow features extraction module and a deep features extraction network. The former exploits the context information aggregation module to adapt to the distribution diversity of rain streaks and extracts the shallow features of rainy image. The latter uses Swin Transformer to capture the global information and long-distance dependencies between different pixels, in combination with residual convolution and dense connection to strengthen features learning. Finally, the derained image is obtained through a global residual convolution. In addition, this paper proposes a novel comprehensive loss function that constrains the similarity of image edges and regions synchronously to further improve the quality of derained image. Extensive experimental results show that, compared with the two state-of-the-art methods, MSPFN and MPRNet, the average peak signal-to-noise ratio of derained images of our method increases by 0.19 dB and 2.17 dB, and the average structural similarity increases by 3.433% and 1.412%. At the same time, the model parameters of the proposed network decreases by 84.59% and 34.53%, and the forward propagation time reduces by 21.25% and 26.67%. Figures and Tables | References | Related Articles | Metrics

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Secure Control for Variable Periodic Switched Positive Systems Under Periodic DoS Attack LIU Jiao, KONG Xiangna, ZHANG Tiantian 2023, 57 (5):  624-630.  doi: 10.16183/j.cnki.jsjtu.2021.445 Abstract ( 355 )   HTML ( 16 )   PDF (689KB) ( 185 )   Save Periodic denial-of-service (DoS) attack prevents the information exchange of measurement channel and control channel for switched positive systems through the network. Moreover, the coupling of system switching behavior and hybrid behavior due to DoS attack and positive constraint also increase the difficulty in secure control research. The secure control problem of networked switched positive systems under periodic DoS attack is studied and a modeling method based on switching behavior is proposed in this paper. Under variable periodic switching, the multiple linear copositive Lyapunov function is constructed to obtain the positive and asymptotically stable condition for the closed-loop system by limiting the relationship between the switching period and the DoS attack period, and a secure state feedback controller based on the positive system theory is designed, based on which, the constant periodic switching case is also discussed by using the positive system theory. Finally, the validity of the results is verified by a simulation example. Figures and Tables | References | Related Articles | Metrics