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    Travel Intention of Electric Vehicle Sharing based on Theory of Multiple Motivations
    BAO Lewen (鲍乐雯), MIAO Rui, ∗ (苗 瑞), CHEN Zhihua (陈志华), ZHANG Bo (张 博), GUO Peng (郭 鹏), MA Yuze (马宇泽)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 1-9.   DOI: 10.1007/s12204-023-2563-5
    Abstract387)      PDF (467KB)(127)      
    Determining the travel intention of residents with shared electric vehicles (EVs) is significant for promoting the development of low-carbon transportation, considering that common problems such as high idle rate and lack of attractiveness still exist. To this end, a structural equation model (SEM) based on the theory of multiple motivations is proposed in this paper. First, the influencing motivations for EV sharing are divided into three categories: consumer-driven, program-driven, and enterprise-driven motivations. Then, the intentions of residents in Shanghai to travel with shared EVs are obtained through a survey questionnaire. Finally, an SEM is constructed to analyze quantitatively the impact of different motivations on the travel intention. The results show that consumer-driven motivations with impact weights from 0.14 to 0.63 have the overwhelming impact on travel intention, compared to program-driven motivations with impact weights from ?0.14 to 0.15 and enterprise-driven motivations with impact weights from 0.02 to 0.06. In terms of consumer-driven motivations, the weight of green travel awareness is the highest. The implications of these results on the policy to enable large-scale implementation of shared EVs are discussed from the perspectives of the resident, enterprise, and government.
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    Integrated Hydraulic-Driven Wearable Robot for Knee Assistance
    ZHAO Yafei (赵亚飞), HUANG Chaoyi (黄超逸), ZOU Yuging(邹玉莹), ZOUKehan(邹可涵), zoU Xiaogang(邹笑阳), XUE .Jiaqi(薛嘉琦), LI Xiaoting(李晓婷), KOH Keng Huat, WANG Xiaojun(王小军), LAI Wai Chiu King(赖伟超), HU Yong(胡勇), XI Ning(席宁), WANG Zheng(王峥)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 289-295.   DOI: 10.1007/s12204-023-2602-2
    Abstract304)      PDF (1156KB)(135)      
    Age-related diseases can lead to knee joint misfunction, making knee assistance necessary through the use of robotic wearable braces. However, existing wearable robots face challenges in force transmission and human motion adaptation, particularly among the elderly. Although soft actuators have been used in wearable robots, achieving rapid response and motion control while maintaining portability remains challenging. To address these issues, we propose a soft-robotic knee brace system integrated with multiple sensors and a direct-drive hydraulic actuation system. This approach allows for controlled and rapid force output on the portable hydraulic system. The multi-sensor feedback structure enables the robotic system to collaborate with the human body through human physiological signal and body motion information. The human user tests demonstrate that the knee robot provides assistive torques to the knee joint by being triggered by the electromyography signal and under human motion control.
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    Physical Characterization of Ionic Liquid-Modified Polyvinyl Alcohol and Sodium Thiocyanate Polymer Electrolytes for Electrochemical Double-Layer Capacitor Application
    AZEMTSOP Manfo Theodore , MEHRA Ram Mohan , KUMAR Yogesh , GUPTA Meenal
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 161-171.   DOI: 10.1007/s12204-021-2397-y
    Abstract295)      PDF (1140KB)(110)      
    Novel gel polymer electrolytes (GPEs) composed of polyvinyl alcohol (PVA) and sodium thiocyanate were developed via a solution casting technique. An ionic liquid (IL), 1-ethyl-3-methyl-imidazolium tricyanomethanide ([EMIM][TCM]), was doped into a polymer–salt complex system (PVA + NaSCN) to further enhance the conductivity. IL-doped polymer electrolyte (ILDPE) films were characterized using X-ray diffraction (XRD), polarized optical microscopy (POM), Fourier-transform infrared (FTIR) spectroscopy, and conductivity measurements. XRD was performed to check the degree of crystallinity and amorphicity of the ILDPE films, and the amorphicity of GPEs increased with the increase of the IL content. POM was employed to evaluate the changes in the surface morphology due to the inclusion of salt and IL in the PVA. The compositional nature of the GPE films was examined via FTIR studies. The electrical and electrochemical properties were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The maximum conductivity for the GPE film was estimated to be 1.10 × 10-5 S/cm for 6% (mass fraction) of IL in the polymer–salt complex. The ionic transference number was approximately 0.97. An electrochemical double-layer capacitor (EDLC) was built from optimized GPE films and reduced graphene oxide-based electrodes. The specific capacitance calculated from the cyclic voltammograms of the EDLC cells was 3 F/g.
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    Strength-Toughness Improvement of 15-5PH Stainless Steel by Double Aging Treatment
    TE Rigele (特日格乐), ZHANG Yutuo, ∗ (张玉妥)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 270-279.   DOI: 10.1007/s12204-021-2390-5
    Abstract284)      PDF (3166KB)(57)      
    To obtain better strength-toughness balance of 15-5PH stainless steel, a double aging treatment is proposed to investigate the mechanical properties and microstructure evolution. In this study, Cu precipitates and reversed austenite played a determining role to improve strength-toughness combination. The microstructure was observed using electron backscattered diffraction, transmission electron microscopy and scanning transmission electron microscopy. The volume fractions of Cu precipitates and reversed austenite were calculated with Thermo-Calc software and measured by X-ray diffraction. The results showed that the reversed austenite is formed at the martensitic lath boundaries and its volume fraction also increases with the increase of the aging temperature. At the same time, the size of the Cu precipitates gradually increases. Compared with the traditional single aging and double aging treatment, double aging treatment of 15-5PH stainless steel can increase the toughness while retaining the necessary strength. During double aging of 550 ℃ × 4 h + 580 ℃ × 1 h, 15-5PH stainless steel has the best strength and low-temperature (- 40 ℃) toughness match. Its yield strength, ultimate tensile strength and the Charpy impact energy are 1.037 GPa, 1.086 GPa and 179 J, respectively.
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    Intelligent Driving Assistance System for Safe Expressway Driving in Rainy and Foggy Weather based on IoT
    YAN Beirui (燕北瑞), FANG Cheng (方 成), QIU Hao (邱 昊), ZHU Wenfeng∗ (朱文峰)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 10-19.   DOI: 10.1007/s12204-023-2564-4
    Abstract269)      PDF (2162KB)(50)      
    The feature bends and tunnels of mountainous expressways are often affected by bad weather, specifically rain and fog, which significantly threaten expressway safety and traffic efficiency. In order to solve this problem, a vehicle–road coordination system based on the Internet of Things (IoT) is developed that can share vehicle–road information in real time, expand the environmental perception range of vehicles, and realize vehicle–road collaboration. It helps improve traffic safety and efficiency. Further, a vehicle–road cooperative driving assistance system model is introduced in this study, and it is based on IoT for improving the driving safety of mountainous expressways. Considering the influence of rain and fog on driving safety, the interaction between rainfall, water film, and adhesion coefficient is analyzed. An intelligent vehicle–road coordination assistance system is constructed that takes in information on weather, road parameters, and vehicle status, and takes the stopping sight distance model as well as rollover and sideslip model as boundary constraints. Tests conducted on a real expressway demonstrated that the assistance system model is helpful in bad weather conditions. This system could promote intelligent development of mountainous expressways.
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    Design of Twin-Screw Compressor Rotor Tooth Profile with Meshing Clearance Based on Graphic Method and Alpha Shape Algorithm
    YANG Jian, ∗ (杨 剑), XU Mingzhao (徐明照), LU Zheng (陆 征)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 243-254.   DOI: 10.1007/s12204-021-2396-z
    Abstract223)      PDF (1955KB)(32)      
    Rotor clearance is necessary for the safe operation of twin-screw compressors, and it has a major impact on the performance of twin-screw compressors. The purpose of this study was to obtain a rotor tooth profile with reasonable meshing clearance on the rotor end surface, so that the clearance on the rotor contact line would be uniform and the rotor could be smoothly meshed. Under ideal conditions, the rotor of a screw compressor should have no clearance or interference. However, owing to assembly errors, thermal compression, stress deformation, and other factors, a rotor without backlash modification will inevitably produce interference during operation. A new design method based on the Alpha shape solution was proposed to achieve an efficient and high-precision design of the clearance of the twin-screw rotor profile. This method avoids the complex analytical calculations in the traditional envelope principle. The best approximation of the points on the rotor conjugate motion sweeping surface in the points is illuminated using a specific color. The sweeping surface of the screw rotor single-tooth profile is roughly scanned to capture the base point set of the sweeping surface boundary points. The chord length and tilt angle of each interval are calculated using the value of the base point set to adjust the position, phase, and magnification of each interval sweeping surface. Finally, the data point set is converted to the same coordinate system to generate the conjugated rotor profile. An example was used to verify the feasibility and adaptability of this method. Based on the equidistant profile method, the clearance between male and female rotors of a screw compressor was obtained under actual operation conditions. Therefore, this study provides a basis for the meshing clearance design in the machining of twin-screw compressor rotors.
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    Mechanical Analysis Methods of Cantilever Gearbox Housing
    WANG Jue∗ (王 珏), LI Peng (李 朋), SONG Shiyao (宋诗瑶)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 233-242.   DOI: 10.1007/s12204-021-2316-2
    Abstract222)      PDF (2037KB)(36)      
    The mechanical state of cantilever gearbox housing is different from ordinary ones due to the long arm of force caused by cantilever structure. Conventional mechanical analysis methods either took cantilever gearbox housing as ordinary ones or cantilever beam. Few published papers have specially focused on mechanical analysis method for cantilever gearbox housing. This paper takes a longwall shearer cutting unit gearbox (SCUG) as an example and the mechanical analysis method is investigated according to the causes of fatigue for SCUG. Force analysis model is established for finding out regions of static fatigue caused by low-frequency loads, and local resonance analysis is used for finding out regions of vibration fatigue caused by high-frequency loads. Not only bending moment but also torque caused by gear meshing forces is taken into account in the force analysis model. Vibration response is obtained from cutting experiment, and dominant frequencies of local resonance are obtained by frequency domain analysis. Finite element model of SCUG is established, and natural frequencies and strain modes are analyzed for obtaining the main vibration modes corresponding to dominant frequencies. Hence, large stress regions caused by low and high frequency loads are obtained. Results show that the worst working condition is oblique cutting, and the stress of B-B in 600 mm cutting depth can reach 166 MPa. Obviously, 950 Hz, 1 250 Hz, and 1 400 Hz are dominant frequencies of SCUG (23rd, 25th and 27th natural frequencies). Generally, this paper proposes some principles for mechanical analysis method of cantilever gearbox housing.
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    Action-aware Encoder-Decoder Network for Pedestrian Trajectory Prediction
    FU Jiawei∗ (傅家威), ZHAO Xu (赵 旭)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 20-27.   DOI: 10.1007/s12204-023-2565-3
    Abstract221)      PDF (775KB)(72)      
    Accurate pedestrian trajectory predictions are critical in self-driving systems, as they are fundamental to the response- and decision-making of ego vehicles. In this study, we focus on the problem of predicting the future trajectory of pedestrians from a first-person perspective. Most existing trajectory prediction methods from the first-person view copy the bird’s-eye view, neglecting the differences between the two. To this end, we clarify the differences between the two views and highlight the importance of action-aware trajectory prediction in the first-person view. We propose a new action-aware network based on an encoder-decoder framework with an action prediction and a goal estimation branch at the end of the encoder. In the decoder part, bidirectional long short-term memory (Bi-LSTM) blocks are adopted to generate the ultimate prediction of pedestrians’ future trajectories. Our method was evaluated on a public dataset and achieved a competitive performance, compared with other approaches. An ablation study demonstrates the effectiveness of the action prediction branch.
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    Lidar-Visual-Inertial Odometry with Online Extrinsic Calibration
    MAO Tianyang (茅天阳), ZHAO Wentao (赵文韬), WANG Jingchuan∗ (王景川), CHEN Weidong (陈卫东)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 70-76.   DOI: 10.1007/s12204-023-2570-6
    Abstract201)      PDF (988KB)(52)      
    To achieve precise localization, autonomous vehicles usually rely on a multi-sensor perception system surrounding the mobile platform. Calibration is a time-consuming process, and mechanical distortion will cause extrinsic calibration errors. Therefore, we propose a lidar-visual-inertial odometry, which is combined with an adapted sliding window mechanism and allows for online nonlinear optimization and extrinsic calibration. In the adapted sliding window mechanism, spatial-temporal alignment is performed to manage measurements arriving at different frequencies. In nonlinear optimization with online calibration, visual features, cloud features, and inertial measurement unit (IMU) measurements are used to estimate the ego-motion and perform extrinsic calibration. Extensive experiments were carried out on both public datasets and real-world scenarios. Results indicate that the proposed system outperforms state-of-the-art open-source methods when facing challenging sensor-degenerating conditions.
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    Indoor Vehicle Positioning Based on Multi-Sensor Data Fusion
    WANG Mingyang (王明阳), SHI Liangren∗ (时良仁), LI Yuanlong (李元龙)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 77-85.   DOI: 10.1007/s12204-023-2571-5
    Abstract200)      PDF (705KB)(40)      
    This study proposes a Kalman filter-based indoor vehicle positioning method for cases in which the steering angle and rotation speed of the vehicle’s wheels are unknown. By fusing the position and velocity data from the ultra-wideband sensors and acceleration and orientation data from the inertial measurement unit, we developed two algorithms to estimate the real-time position of the vehicle based on a linear Kalman filter and extended Kalman filter, respectively. We then conducted simulations and experiments to examine the performances of the algorithms. In the experiment, the Kalman filtering hyperparameters are configured, and we then ran the two algorithms to determine the positioning precision and accuracy with the ground truth produced via LiDAR. We verified that our method can improve precision and accuracy compared with the raw positioning data and can achieve desirable effects for indoor vehicle positioning when vehicles travel at low speeds.
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    Infrastructure-Based Vehicle Localization System for Indoor Parking Lot Using RGB-D Cameras
    CAO Bingquan1,2,3 (曹炳全), HE Yuesheng1,2,3∗ (贺越生), ZHUANG Hanyang4 (庄瀚洋), YANG Ming1,2,3 (杨 明)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 61-69.   DOI: 10.1007/s12204-023-2569-z
    Abstract196)      PDF (1606KB)(29)      
    Accurate vehicle localization is a key technology for autonomous driving tasks in indoor parking lots, such as automated valet parking. Additionally, infrastructure-based cooperative driving systems have become a means to realizing intelligent driving. In this paper, we propose a novel and practical vehicle localization system using infrastructure-based RGB-D cameras for indoor parking lots. In the proposed system, we design a depth data preprocessing method with both simplicity and efficiency to reduce the computational burden resulting from a large amount of data. Meanwhile, the hardware synchronization for all cameras in the sensor network is not implemented owing to the disadvantage that it is extremely cumbersome and would significantly reduce the scalability of our system in mass deployments. Hence, to address the problem of data distortion accompanying vehicle motion, we propose a vehicle localization method by performing template point cloud registration in distributed depth data. Finally, a complete hardware system was built to verify the feasibility of our solution in a real-world environment. Experiments in an indoor parking lot demonstrated the effectiveness and accuracy of the proposed vehicle localization system, with a maximum root mean squared error of 5 cm at 15 Hz compared with the ground truth.
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    Ant Colony Algorithm Path Planning Based on Grid Feature Point Extraction
    LI Erchao∗ (李二超), QI Kuankuan (齐款款)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 86-99.   DOI: 10.1007/s12204-023-2572-4
    Abstract195)      PDF (1196KB)(102)      
    Aimed at the problems of a traditional ant colony algorithm, such as the path search direction and field of view, an inability to find the shortest path, a propensity toward deadlock and an unsmooth path, an ant colony algorithm for use in a new environment is proposed. First, the feature points of an obstacle are extracted to preprocess the grid map environment, which can avoid entering a trap and solve the deadlock problem. Second, these feature points are used as pathfinding access nodes to reduce the node access, with more moving directions to be selected, and the locations of the feature points to be selected determine the range of the pathfinding field of view. Then, based on the feature points, an unequal distribution of pheromones and a two-way parallel path search are used to improve the construction efficiency of the solution, an improved heuristic function is used to enhance the guiding role of the path search, and the pheromone volatilization coefficient is dynamically adjusted to avoid a premature convergence of the algorithm. Third, a Bezier curve is used to smooth the shortest path obtained. Finally, using grid maps with a different complexity and different scales, a simulation comparing the results of the proposed algorithm with those of traditional and other improved ant colony algorithms verifies its feasibility and superiority.
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    Numerical Study on Separation of Circulating Tumor Cell Using Dielectrophoresis in a Four-Electrode Microfluidic Device
    WANG Yukuna (王雨坤), DING Xiantingb (丁显廷), ZHANG Zhinana (张执南)
    J Shanghai Jiaotong Univ Sci    2023, 28 (4): 391-.   DOI: 10.1007/s12204-022-2459-9
    Abstract192)      PDF (1462KB)(176)      
    This numerical study proposes a cell sorting technique based on dielectrophoresis (DEP) in a microfluidic chip. Under the joint effect of DEP and fluid drag, white blood cells and circulating tumor cells are separated because of different dielectric properties. First, the mathematical models of device geometry, single cell, DEP force, electric field, and flow field are established to simulate the cell motion. Based on the simulation model, important boundary parameters are discussed to optimize the cell sorting ability of the device. A proper matching relationship between voltage and flow rate is then provided. The inlet and outlet conditions are also investigated to control the particle motion in the flow field. The significance of this study is to verify the cell separating ability of the microfluidic chip, and to provide a logistic design for the separation of rare diseased cells.
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    Electric vehicle charging situation awareness for charging station ultra-short-term load forecast
    SHI Yiwei1 (史一炜), LIU Zeyu1 (刘泽宇), FENG Donghan1∗ (冯冬涵), ZHOU Yun1∗ (周 云), ZHANG Kaiyu2 (张开宇), LI Hengjie3 (李恒杰)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 28-38.   DOI: 10.1007/s12204-023-2566-2
    Abstract191)      PDF (1518KB)(163)      
    Electric vehicles (EVs) are expected to be key nodes connecting transportation–electricity–communication networks. Advanced automotive electronics technologies enhance EVs’ perception, computing, and communication capacity, which in turn can boost the operational efficiency of intelligent transportation systems (ITSs). EVs couple the ITS to the power system, providing a promising solution to charging congestion and transformer overload via navigation and forecasting approaches. This study proposes a privacy-preserving EV charging situation awareness framework and method to forecast the ultra-short-term load of charging stations. The proposed method only relies on public information from commercial service providers. In the case study, data are powered by the Baidu LBS cloud and EV-SGCC platform, and the experiment is conducted within an area of Pudong New District in Shanghai. Based on the results, the charging load of charging stations can be adequately forecasted more than 1 min ahead with low communication and computing power requirements. This research provides the basis for further studies on operation optimization and electricity market transaction of charging stations.
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    Synthesis and Characterization of Copper Doped Zinc Oxide Thin Films Deposited by RF/DC Sputtering Technique
    KHAN Mohibul, ALAM Md. Shabaz, AHMED Sk. Faruque∗
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 172-179.   DOI: 10.1007/s12204-022-2462-1
    Abstract189)      PDF (698KB)(48)      
    Undoped and copper (Cu) doped zinc oxide (Zn1-xCuxO, where x = 0—0.065) nano crystal thin films have been deposited on glass substrate via RF/DC reactive co-sputtering technique. The aim of this work is to investigate the crystal structure of ZnO and Cu doped ZnO thin films and also study the effect of Cu doping on optical band gap of ZnO thin films. The identification and confirmation of the crystallinity, film thickness and surface morphology of the nano range thin films are confirmed by using X-ray diffractometer (XRD), scanning electron microscope and atomic force microscope. The XRD peak at a diffractive angle of 34.44° and Miller indices at (002) confirms the ZnO thin films. Crystallite size of undoped ZnO thin films is 27 nm and decreases from 27 nm to 22 nm with increasing the atomic fraction of Cu (xCu) in the ZnO thin films from 0 to 6.5% respectively, which is calculated from XRD (002) peaks. The different bonding information of all deposited films was investigated by Fourier transform infrared spectrometer in the range of wave number between 400 cm-1 to 4 000 cm-1. Optical band gap energy of all deposited thin films was analyzed by ultraviolet visible spectrophotometer, which varies from 3.35 eV to 3.19 eV with the increase of xCu from 0 to 6.5% respectively. Urbach energy of the deposited thin films increases from 115 meV to 228 meV with the increase of xCu from 0 to 6.5% respectively.
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    Foreground Segmentation Network with Enhanced Attention
    JIANG Rui1*(姜﹐锐),ZHU Ruiriang1(朱瑞祥),CAI Xiaocui1(蔡萧萃),SU Hu2(苏虎)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 360-369.   DOI: 10.1007/s12204-023-2603-1
    Abstract187)      PDF (734KB)(31)      
    Moving object segmentation (MOS) is one of the essential functions of the vision system of all robots,including medical robots. Deep learning-based MOS methods, especially deep end-to-end MOS methods, are actively investigated in this field. Foreground segmentation networks (FgSegNets) are representative deep end-to-end MOS methods proposed recently. This study explores a new mechanism to improve the spatial feature learning capability of FgSegNets with relatively few brought parameters. Specifically, we propose an enhanced attention (EA) module, a parallel connection of an attention module and a lightweight enhancement module, with sequential attention and residual attention as special cases. We also propose integrating EA with FgSegNet v2 by taking the lightweight convolutional block attention module as the attention module and plugging EA module after the two Maxpooling layers of the encoder. The derived new model is named FgSegNet v2 EA. The ablation study verifies the effectiveness of the proposed EA module and integration strategy. The results on the CDnet2014 dataset, which depicts human activities and vehicles captured in different scenes, show that FgSegNet v2 EA outperforms FgSegNet v2 by 0.08% and 14.5% under the settings of scene dependent evaluation and scene independent evaluation, respectively, which indicates the positive effect of EA on improving spatial feature learning capability of FgSegNet v2.
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    Novel Concentric Tube Robot Based on Double-Threaded Helical Gear Tube
    CHEN Weichi(陈韦池), LIU Haocheng(刘浩城), LI Zijian(李子建), GUO Jing, (郭靖), ZHAI Zhenkun(翟振坤), MENG Wei(孟伟)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 296-306.   DOI: 10.1007/s12204-023-2595-x
    Abstract185)      PDF (2087KB)(58)      
    Nasopharyngeal carcinoma is a malignant tumor originating from the nasal mucosa. It is a malignant tumor of the head and neck. Concentric tube robot (CTR), as it can form a complicated shape and access hardto-reach lesions, is often used in minimally invasive surgeries. However, some CTRs are bulky because of their transmission design. In this paper, a light CTR based on double-threaded helical gear tube is proposed. Such a CTR is less cumbersome than the traditional CTR as its actuation unit is compact and miniaturized. The mapping relationship between the gear tube attitude and motor output angle is obtained by kinematic analysis. The precision, stability, and repeatability of the driving mechanism are tested. The experimental results show that the positioning error in the translation test is less than 0.3 mm, the rolling angle error in the stability test is less than 0.6?, and the error in the translation repeatability test is less than 0.005 mm. Finally, a tip-targeting test is performed using the new CTR, which verifies the feasibility of the CTR for surgeries.
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    Birds-Eye-View Semantic Segmentation and Voxels Semantic Segmentation Based on Frustum Voxels Modeling and Monocular Camera
    QIN Chao1 (秦 超), WANG Yafei1 (王亚飞), ZHANG Yuchao2 (张宇超), YIN Chengliang1∗ (殷承良)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 100-113.   DOI: 10.1007/s12204-023-2573-3
    Abstract174)      PDF (3885KB)(55)      
    The semantic segmentation of a bird’s-eye view (BEV) is crucial for environment perception in autonomous driving, which includes the static elements of the scene, such as drivable areas, and dynamic elements such as cars. This paper proposes an end-to-end deep learning architecture based on 3D convolution to predict the semantic segmentation of a BEV, as well as voxel semantic segmentation, from monocular images. The voxelization of scenes and feature transformation from the perspective space to camera space are the key approaches of this model to boost the prediction accuracy. The effectiveness of the proposed method was demonstrated by training and evaluating the model on the NuScenes dataset. A comparison with other state-of-the-art methods showed that the proposed approach outperformed other approaches in the semantic segmentation of a BEV. It also implements voxel semantic segmentation, which cannot be achieved by the state-of-the-art methods.
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    Band Structure Characteristics of Two-Dimensional Si-A (Ge, Pb, Sn) Alloy-Air Holes Thermal Crystals
    AZKA Umar ∗, JIANG Chun (姜 淳), KHUSHIK Muhammad Hanif Ahmed Khan
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 180-185.   DOI: 10.1007/s12204-022-2485-7
    Abstract166)      PDF (539KB)(37)      
    This paper designs the thermal crystals composed of alloy materials with air holes and analyzes their properties of band structures, heat transmission, and flux spectra. Thermal crystals composed of Si-A (A=Ge, Sn, Pb) alloys as background materials and air holes with square array are used to construct an elastic-constant periodic structure and their high-frequency phononic band is calculated by deploying finite element methods. Moreover, this paper investigates heat transmission through a finite array of thermally excited phonons and presents the thermal crystal with maximum heat transport. The results show that a wider bandgap could be achieved by increasing the air hole radius and decreasing the lattice constant. In the alloy materials, with increasing atomic radius and thus atomic mass (Ge, Sn, Pb), the frequency range (contributed to thermal conductivity) shifts towards lower frequency. Hence, the bandgap frequencies also shift toward low frequency, but this decreasing rate is not constant or in order, so former may have a faster or slower decreasing rate than the later. Thus, the frequency range for the contribution of heat transportation overlaps with the bandgap frequency range. The development of thermal crystals is promising for managing heat and controlling the propagation of the thermal wave.
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    Progress in Force-Sensing Techniques for Surgical Robots
    GAO Hongyan1,2(高红岩),AI Xiaojie1,2(艾孝杰),SUN Zhenglong3(孙正隆),CHEN Weidong1,2(陈卫东),GAO Anzhu1,2*(高安柱)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 370-381.   DOI: 10.1007/s12204-023-2607-x
    Abstract162)      PDF (1017KB)(50)      
    Force sensing is vital for situational awareness and safe interaction during minimally invasive surgery. Consequently, surgical robots with integrated force-sensing techniques ensure precise and safe operations. Over the past few decades, there has been considerable progress in force-sensing techniques for surgical robots. This review summarizes the existing electrically- and optically-based force sensors for surgical robots, including piezoresistive, piezoelectric, capacitive, intensity/phase-modulated, and fiber Bragg gratings. Their principles, applications, advantages, and limitations are also discussed. Finally, we summarize our conclusions regarding state-of-the-art force-sensing technologies for surgical robotics.
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    Research on Real-time Dynamic Evaluation of Highway Passenger Service Satisfaction Based on Internet
    LUO Jing1 (罗 京), ZHOU Dai1∗ (周 岱), TAN Yunlong2 (谭云龙), XIA Ganlin3 (夏甘霖), ZHAO Guohua4,5 (赵国华)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 39-51.   DOI: 10.1007/s12204-023-2568-0
    Abstract160)      PDF (556KB)(36)      
    The current method of evaluating passenger satisfaction primarily adopts the traditional static evaluation mode, which can hardly satisfy the dynamic regulatory requirements of highway passenger transport service quality set by industry management departments. In this paper, we summarize the characteristics of real-time dynamic evaluation under the requirements of hierarchical and classified evaluation and analyze the entire process of the one-time travel service of highway passenger transport. We focus on station waiting and in-vehicle services, extract the elements most concerned by passengers as evaluation indexes, and construct a three-level index system. Subsequently, a multi-indicator comprehensive evaluation method based on the analytic hierarchy process and fuzzy comprehensive evaluation is selected to construct a comprehensive evaluation model. By combining with the development level of electronic ticket purchasing and the requirements of satisfaction evaluation, we propose three data collection methods and compare and analyze their strengths and weaknesses. Finally, based on actual survey data, the effectiveness of the model is verified. The verification results show that the real-time dynamic evaluation index system based on the Internet can better satisfy evaluation requirements.
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    Shape Sensing for Single-Port Continuum Surgical Robot Using Few Multicore Fiber Bragg Grating Sensors
    LI Dingjia1,2,3,4(黎定佳),WANG Chongang1,2,3(王重阳),GUO Wei5(郭伟),WANG Zhidong6(王志东),ZHANG Zhongtao5(张忠涛),LIU Hao1,2,3*(刘浩)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 312-322.   DOI: 10.1007/s12204-023-2579-x
    Abstract157)      PDF (2606KB)(33)      
    We proposed a method for shape sensing using a few multicore fiber Bragg grating (FBG) sensors in a single-port continuum surgical robot (CSR). The traditional method of utilizing a forward kinematic model to calculate the shape of a single-port CSR is limited by the accuracy of the model. If FBG sensors are used for shape sensing, their accuracy will be affected by their number, especially in long and flexible CSRs. A fusion method based on an extended Kalman filter (EKF) was proposed to solve this problem. Shape reconstruction was performed using the CSR forward kinematic model and FBG sensors, and the two results were fused using an EKF. The CSR reconstruction method adopted the incremental form of the forward kinematic model, while the FBG sensor method adopted the discrete arc-segment assumption method. The fusion method can eliminate the inaccuracy of the kinematic model and obtain more accurate shape reconstruction results using only a small number of FBG sensors. We validated our algorithm through experiments on multiple bending shapes under different load conditions. The results show that our method significantly outperformed the traditional methods in terms of robustness and effectiveness.
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    Safety Evaluation of Commercial Vehicle Driving Behavior Based on AHP-CRITIC Algorithm
    PANG Na1 (庞 娜), LUO Wenguang1∗ (罗文广), WU Ruoyuan1 (吴若园), LAN Hongli1 (蓝红莉), QIN Yongxin1 (覃永新), SU Qi2 (苏 琦)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 126-135.   DOI: 10.1007/s12204-023-2575-1
    Abstract147)      PDF (421KB)(30)      
    To prevent and reduce road traffic accidents and improve driver safety awareness and bad driving behaviors, we propose a safety evaluation method for commercial vehicle driving behavior. Three driving style classification indexes were extracted using driving data from commercial vehicles and four primary and ten secondary safety evaluation indicators. Based on the stability of commercial vehicles transporting goods, the acceleration index is divided into three levels according to the statistical third quartile, and the evaluation expression of the safety index evaluation is established. Drivers were divided into conservative, moderate, and radical using Kmeans++. The weights corresponding to each index were calculated using a combination of the analytic hierarchy process (AHP) and criteria importance through intercriteria correlation (CRITIC), and the driving behavior scores of various drivers were calculated according to the safety index score standard. The established AHP–CRITIC safety evaluation model was verified using the actual driving behavior data of commercial vehicle drivers. The calculation results show that the proposed evaluation model can clearly distinguish between the types of drivers with different driving styles, verifying its rationality and validity. The evaluation results can provide a reference for transportation management departments and enterprises.
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    Visual Positioning of Nasal Swab Robot Based on Hierarchical Decision
    LI Guozhia a(李国志),ZOU Shuizhong b*(邹水中),DING Shuacue a(丁数学)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 323-329.   DOI: 10.1007/s12204-023-2581-3
    Abstract146)      PDF (743KB)(33)      
    This study focuses on a robot vision localization method for coping with the operational task of automatic nasal swab sampling. The application is important in the detection and epidemic prevention of Corona Virus Disease 2019 (COVID-19) to alleviate the large-scale negative impact of individuals suffering from pneumonia owing to COVID-19. In this method, the idea of a hierarchical decision network is used to consider the strong infectious characteristics of the COVID-19, which is followed by processing the robot behavior constraint condition. The visual navigation and positioning method using a single-arm robot for sampling is also planned, which considers the operation characteristics of medical staff. In the decision network, the risk factor for potential contact infection caused by swab sampling operations is established to avoid the spread among personnel. A robot visual servo control with artificial intelligence characteristics is developed to achieve a stable and safe nasal swab sampling operation. Experiments demonstrate that the proposed method can achieve good vision positioning for the robots and provide technical support for managing new major public health situations.
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    Spatial Temporal Correlation 3D Vehicle Detection and Tracking System with Multiple Surveillance Cameras
    XUE Weipeng (薛炜彭), WU Minghu (吴明虎), WANG Lin∗ (王 琳)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 52-60.   DOI: 10.1007/s12204-023-2567-1
    Abstract146)      PDF (1375KB)(41)      
    Compared to 3D object detection using a single camera, multiple cameras can overcome some limitations on field-of-view, occlusion, and low detection confidence. This study employs multiple surveillance cameras and develops a cooperative 3D object detection and tracking framework by incorporating temporal and spatial information. The framework consists of a 3D vehicle detection model, cooperatively spatial-temporal relation scheme, and heuristic camera constellation method. Specifically, the proposed cross-camera association scheme combines the geometric relationship between multiple cameras and objects in corresponding detections. The spatial-temporal method is designed to associate vehicles between different points of view at a single timestamp and fulfill vehicle tracking in the time aspect. The proposed framework is evaluated based on a synthetic cooperative dataset and shows high reliability, where the cooperative perception can recall more than 66% of the trajectory instead of 11% for single-point sensing. This could contribute to full-range surveillance for intelligent transportation systems.
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    Cascade Optimization Control of Unmanned Vehicle Path Tracking under Harsh Driving Conditions
    HUANG Yinggang1 (黄迎港), LUO Wenguang1∗ (罗文广), HUANG Dan2 (黄 丹), LAN Hongli1 (蓝红莉)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 114-125.   DOI: 10.1007/s12204-023-2574-2
    Abstract143)      PDF (2166KB)(31)      
    Under ultra-high-speed and harsh conditions, conventional control methods struggle to ensure the path tracking accuracy and driving stability of unmanned vehicles during the turning process. Therefore, this study proposes a cascade control to solve this problem. Based on the new vehicle error model that considers vehicle tire sideslip and road curvature, the feedforward-parametric adaptive linear quadratic regulator (LQR) and proportional integral control-based speed-keeping controllers are used to compose the path-tracking cascade optimization controller for unmanned vehicles. To improve the adaptability of the unmanned vehicle path-tracking control under harsh driving conditions, the LQR controller parameters are automatically adjusted using a backpropagation neural network, in which the initial weights and thresholds are optimized using the improved grey wolf optimization algorithm according to the driving conditions. The speed-keeping controller reduces the impact on the curve-tracking accuracy under nonlinear vehicle speed variations. Finally, a joint model of MATLAB/Simulink and CarSim was established, and simulations show that the proposed control method can achieve stable entry and exit curves at ultra-high speeds for unmanned vehicles. Under strong wind and ice road conditions, the method exhibits a higher tracking accuracy and is more adaptive and robust to external interference in driving and variable curvature roads than methods such as the feedforward-LQR, preview and pure pursuit controls.
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    In-Plane Elastic Properties of Stitched Plain Weave Composite Laminate
    YUAN Lihua (袁丽华), LIANG Sen∗ (梁 森), YAN Shengyu (闫盛宇)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 220-232.   DOI: 10.1007/s12204-021-2375-4
    Abstract142)      PDF (1646KB)(36)      
    A representative volume element method and a novel mesomechanical-based polyline model are proposed to describe the misalignment of in-plane fibers induced by the insertion of stitch thread. A multi-scale mathematical model of in-plane elastic parameters for stitched composite laminate is established with ply-angle and stitch parameters as well as material parameters taken into account. Based on the fabrication of specimens and the verification of experimental platform, the superposition influences of stitch on structural anisotropy are revealed by the developed theoretical model. Results indicate that the stitch orientation can increase the structural anisotropy. The decreases of stitch pitch and spacing as well as the increase of thread diameter obviously reduce the elastic and shear moduli of laminates. Furthermore, the elastic and shear moduli as well as Poisson’s ratios show sinusoidal changes with a period of 90° as the ply-angle increases. The theoretical model not only analyzes the in-plane mechanical properties of stitched laminate with ply-angle, but also lays a foundation for the dynamic studies of stitched sandwich structures with ribs in the future.
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    Effect of Fast Multiple Rotation Rolling on Microstructure and Properties of Ti6Al4V Alloy
    YANG Xiaojie, (杨晓洁), CHANG Xueting∗ (常雪婷), FAN Runhua (范润华)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 264-269.   DOI: 10.1007/s12204-021-2395-0
    Abstract140)      PDF (1470KB)(27)      
    Using fast multiple rotation rolling (FMRR), a nanostructure layer was fabricated on the surface of Ti6Al4V alloy. The microstructure of the surface layer was investigated using optical microscopy, transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The results indicated that a nanostructured layer, with an average grain size of 72—83 nm, was obtained in the top surface layer, when the FMRR duration was 15 min. And the average grain size further reduced to 24—37 nm when the treatment duration increased to 45 min. High density dislocations, twins, and stacking faults were observed in the top surface layer. The microhardness of FMRR specimen, compared with original specimen, was significantly increased. A uniform, continuous and thicker compound layer was obtained in the top surface of FMRR sample, and the diffusion speed of N atom in the top surface layer was accelerated. FMRR treatment provides corrosion improvement.
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    Influence of Forming Pressure on Properties of Yttrium Iron Garnet Ferrite
    CHEN Zhigang (陈志刚), LI Haihua∗ (李海华)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 207-212.   DOI: 10.1007/s12204-022-2478-6
    Abstract139)      PDF (589KB)(24)      
    The Ca-Sn co-substituted yttrium iron garnet (YIG) ferrite materials were prepared by the traditional oxide solid-state reaction method, and the influence of forming pressure on the density, morphology and magnetic properties of YIG ferrite was systematically studied. The results show that the density of YIG ferrite green body increases with the increase of the forming pressure, while the density of its sintered body shows a trend of first increasing and then decreasing. At the same time, the ferromagnetic resonance (FMR) linewidth of YIG sample first decreases and then increases. Meanwhile, the effects of forming pressure on the saturation magnetization, remanence and coercivity of the sample can be ignored. This study proves that the density and FMR linewidth of YIG materials can be controlled by regulating the forming pressure and the best performance is obtained for the sample prepared under a forming pressure of 5 MPa.
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    Robust Charging Demand Prediction and Charging Network Planning for Heterogeneous Behavior of Electric Vehicles
    ZHANG Yilun1‡ (张轶伦), XU Sikun2‡ (徐思坤), XU Jie1 (徐 捷), ZENG Xueqi3 (曾学奇), LI Zheng4 (李 铮), XIE Chi5∗ (谢 驰)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 136-149.   DOI: 10.1007/s12204-023-2576-0
    Abstract136)      PDF (1054KB)(31)      
    This study addresses a new charging station network planning problem for smart connected electric vehicles. We embed a charging station choice model into a charging network planning model that explicitly considers the heterogeneity of the charging behavior in a data-driven manner. To cope with the deficiencies from a small size and sparse behavioral data, we propose a robust charging demand prediction method that can significantly reduce the impact of sample errors and missing data. On the basis of these two building blocks, we form and solve a new optimal charging station location and capacity problem by minimizing the construction and charging costs while considering the charging service level, construction budget, and limit to the number of chargers. We use a case study of planning charging stations in Shanghai to validate our contributions and provide managerial insight in this area.
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    Establishment of a Refined Brain Model for Evaluating Implantation Behavior of Neural Electrode and Research of its Simulated Behavior
    HE Yuxcin (贺雨欣), ZHANG Wenguang (张文光), XU Haotian (胥浩天), XU Yifan (徐倚帆), XU Liyue (许李悦)
    J Shanghai Jiaotong Univ Sci    2023, 28 (4): 401-.   DOI: 10.1007/s12204-022-2523-5
    Abstract135)      PDF (1512KB)(55)      
    The long-term reliability of the neural electrode is closely related to its implantation behavior. In orderto realize the quantitative research of the implantation behavior in a low-cost and accurate way, a refined brainmodel containing meninges is proposed. First, the expected simulation material was selected through measuringthe elastic modulus based on the method of atomic force microscope indentation technique. As a result, the 2%(mass fraction) agarose gel simulated the gray and white matter, the 7 : 1 (volume ratio) polydimethylsiloxane(PDMS) sheet simulated the pia mater, and the polyvinyl chloride (PVC) film simulated the dura mater. Second,based on designing a three-layer structure mold, the brain model was prepared by inverted pouring to realizea flat implantation surface. Finally, the simulation behavior of the brain model was investigated with the ratbrain as a reference. For mechanical behavior of implantation, the implantation force experienced two peaks bothin the brain model and the rat brain, maximum values of which were 10.17 mN and 7.69 mN respectively. Thelarger implantation force in the brain model will increase the strength requirement for the electrode, but reducethe risk of buckling of that in practical application. For humoral dissolution behavior, the dissolution rates ofthe polyethylene glycol (PEG) coating of the electrode in the brain model and rat brain were 7 000 μm3/s and5 600 μm3/s, respectively. The faster dissolution rate in the brain model will cause the larger thickness of thecoating design but provide sufficient implantable time in practical application. The establishment of the brainmodel and the research of its simulated behavior are beneficial to the size design of the electrode substrate andcoating, and research of the implantation mechanism, and further increase the functional life of the electrode.
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    Straight-Going Priority in Hierarchical Control Framework for Right-Turning Vehicle Merging Based on Cooperative Game
    YANG Jingwena (杨静文), ZHANG Libina (张立彬), WANG Pinga (王 萍), YAO Junfengb∗ (姚俊峰), ZHAO Xiangmob (赵祥模)
    J Shanghai Jiaotong Univ Sci    2023, 28 (1): 150-160.   DOI: 10.1007/s12204-023-2577-z
    Abstract133)      PDF (997KB)(47)      
    With the development of connected and automated vehicles (CAVs), forming strategies could extend from the typically used first-come-first-served rules. It is necessary to consider passing priorities when crossing intersections to prevent conflicts. In this study, a hierarchical strategy based on a cooperative game was developed to improve safety and efficiency during right-turning merging. A right-turn merging conflict model was established to analyze the right-turning vehicle characteristics of the traffic flow. The proposed three-layered hierarchical strategy includes a decision-making layer, a task layer, and an operation layer. A decision-making-layer cooperative game strategy was used to determine the merging priority of straight-going traffic and right-turning flows. In addition, a task-layer cooperative game strategy was designed for the merging sequence. A modified consensus algorithm was utilized to optimize the speed of vehicles in the virtual platoon of the operation layer. Traffic simulations were performed on the PYTHON-SUMO integrated platform to verify the proposed strategy. The simulation results show that, compared with other methods, the proposed hierarchical strategy has the shortest travel time and loss time and performs better than other methods when the straight-going traffic flow increases during right-turning merging at the intersection. The proposed method shows superiority under a significant traffic flow with a threshold of 900 vehicle/(h · lane). This satisfactory application of right-turning merging might be extended to ramps, lane-changing, and other scenarios in the future.
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    Numerical Simulation on the Effect of Conveyor Velocity of the Roller Table on Stress Distribution and Evolution in Large Aluminum Alloy Thick Plates
    ZHU Kai, (祝 楷), XIONG Baiqing, ∗ (熊柏青), YAN Hongwei, (闫宏伟), ZHANG Yongan, (张永安), LI Zhihui, (李志辉), LI Xiwu, (李锡武), LIU Hongwei, (刘红伟), WEN Kai, (温 凯), YAN Lizhen, (闫丽珍)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 255-263.   DOI: 10.1007/s12204-021-2389-y
    Abstract131)      PDF (1596KB)(28)      
    Solution heat treatment combined with a rapid quenching operation, which can effectively suppress the decomposition of the supersaturated solid solution in the matrix, is a vital process step for producing large precipitation-hardenable aluminum alloy thick plates with desired properties. However, large thermal gradients that result from the non-uniform cooling rates during quenching usually give rise to severely heterogeneous distributions of residual stress in thick plates. The presence of roller-hearth furnaces makes it possible to achieve continuous and integral solution-quenching treatment for large aluminum alloy thick plates. The conveyor velocity of the roller table in the roller-hearth furnace is a key parameter but its influence is less addressed in literature. Thus, in the present work, finite element thermal-mechanical simulations taking into account different conveyor velocities of the roller table were employed to predict the temperature variations and residual stress distributions in large aluminum alloy thick plates during quenching process. Four different velocities were utilized in the simulations. The modeling results showed that the temperature evolutions as well as the distributions of the induced internal stresses in those large thick plates during quenching treatments were indeed affected by the conveyor velocities. Slower velocities were demonstrated to be favorable for gaining thick plates being with relatively homogeneous residual stress distributions in the plates.
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    Development of Rehabilitation and Assistive Robots in China: Dilemmas and Solutions
    ZHAO Lingling1*(赵玲玲),GUO Yao2(郭遥)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 382-390.   DOI: 10.1007/s12204-023-2596-9
    Abstract130)      PDF (367KB)(32)      
    China is rapidly becoming an aging society, leading to a significant demand for chronic disease management and personalized healthcare. The development of rehabilitation and assistive robotics in China has gathered significant attention not only in research fields but also in industries. Such robots aim to either guide patients in completing therapeutic training or assist people with impaired functions in performing their daily activities. In the past decades, we have witnessed the advancement in rehabilitation and assistive robotics, with diverse mechanical designs, functionalities, and purposes. However, the construction of dedicated regulations and policies is relatively lagged compared with the flourishing development in research fields. Moreover, these kinds of robots are working or collaborating closely with human beings, bringing unprecedented considerations on ethical issues. This paper aims to provide an overview of major dilemmas in the development of rehabilitation and assistive robotics in China and propose several potential solutions.
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    Input-Constrained Hybrid Control of a Hyper-Redundant Mobile Medical Manipulator
    ZHANG Kaibo1(张凯波),CHEN Li1*(陈丽),DONG Qi2(董琦)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 348-359.   DOI: 10.1007/s12204-023-2580-4
    Abstract130)      PDF (909KB)(23)      
    To reduce the risk of infection in medical personnel working in infectious-disease areas, we proposed a hyper-redundant mobile medical manipulator (HRMMM) to perform contact tasks in place of healthcare workers. A kinematics-based tracking algorithm was designed to obtain highly accurate pose tracking. A kinematic model of the HRMMM was established and its global Jacobian matrix was deduced. An expression of the tracking error based on the Rodrigues rotation formula was designed, and the relationship between tracking errors and gripper velocities was derived to ensure accurate object tracking. Considering the input constraints of the physical system, a joint-constraint model of the HRMMM was established, and the variable-substitution method was used to transform asymmetric constraints to symmetric constraints. All constraints were normalized by dividing by their maximum values. A hybrid controller based on pseudo-inverse (PI) and quadratic programming (QP) was designed to satisfy the real-time motion-control requirements in medical events. The PI method was used when there was no input saturation, and the QP method was used when saturation occurred. A quadratic performance index was designed to ensure smooth switching between PI and QP. The simulation results showed that the HRMMM could approach the target pose with a smooth motion trajectory, while meeting different types of input constraints.
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    Low Voltage Indium-Oxide-Zinc Thin Film Transistor Gated by KH550 Solid Electrolyte
    DONG Qian (董 钱), GUO Liqiang(郭立强), WANG Weilin (王伟琳), CHENG Guanggui (程广贵)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 186-191.   DOI: 10.1007/s12204-022-2421-x
    Abstract129)      PDF (763KB)(52)      
    With the development of integrate circuit and artificial intelligence, many kinds of transistors have been invented. In recent years, wide attention has been paid to the oxide thin film transistors due to its ease preparation, low cost, and suitability for mass production. Traditionally used gate dielectric film (such as silicon dioxide film) in oxide thin film transistor owns low dielectric constant, which leads to weak capacitive coupling between the gate dielectric layer and the channel layer. As a result, high voltage (10 V or more) needs to be applied on the gate electrode in order to achieve the purpose of regulating the current of channel layer. Therefore, new oxide thin film needs to be developed. In this work, silane coupling agents (3-triethoxysilypropyla-mine) KH550 solid electrolyte film was obtained by spin coating-process. The KH550 solid electrolyte was used as gate dielectric layer to fabricate low-voltage indium zinc oxide thin film transistor. The surface topography and thickness of KH550 solid electrolyte film were characterized by atomic force microscope and field emission scanning electron microscope, respectively. The capacitance-frequency curve of the sample was measured by impedance analyzer (Soloartron 1260A), and the electrical characteristics of the sample were analyzed by a semiconductor parameter analyzer (Keithley 4200 SCS). A maximum specific capacitance of about 7.3 μF/cm2 is obtained at 1 Hz. The transistor shows a good stability of pulse operation and negative bias voltage, the operation voltage is only 2 V, the current on/off ratio is about 1.24 × 106, and the subthreshold swing is 169.2 mV/dec. The development of KH550 solid electrolyte gate dielectric provides a novel way for the research of oxide thin film transistor.
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    Fabrication and Characterization of Graphene-Enhanced Hollow Microlattice Materials
    BAO Haisheng (鲍海生), LIU Longquan∗ (刘龙权)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 192-196.   DOI: 10.1007/s12204-021-2339-8
    Abstract127)      PDF (662KB)(50)      
    A method was developed and proposed to fabricate graphene-enhanced hollow microlattice materials, which include the three-dimensional (3D) printing, nanocomposite electroless plating, and polymer etching technologies. The surface morphology and uniformity of as-deposited coatings were systematically characterized and analyzed. Moreover, the mechanical properties of the microlattices were investigated through quasi-static compression tests. The results demonstrated that a uniform Nickel-phossphorous-graphene (Ni-P-G) coating was obtained successfully, and the specific modulus and strength were increased by adding graphene into the microlattice materials. The optimal mass concentration of graphene nanoplatelets was obtained after comparing the specific modulus and strength of the materials with different densities of graphene, and the strength mechanism was discussed.
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    Analytical Solution of Thermo-Elastic-Plastic Deformation of the Combined Forging Die
    CAO Minye (曹民业), MIAO Hongliang (苗宏量), HU Chengliang∗ (胡成亮), ZHAO Zhen (赵 震)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 280-288.   DOI: 10.1007/s12204-021-2388-z
    Abstract121)      PDF (1429KB)(31)      
    On the multi-layer forging die used in daily life, stressed ring can strength the die structure within elastic deformation and the die material can be self-strengthened through uniform plastic deformation by autofrettage effect, whereas the thermal effect generated during forging process can directly influence the stress state and dimension of the forging die in service. In this study, an analytical solution of the thermo-elastic-plastic deformation in the forging die is derived. The relationships between the radial and circumferential stresses and the temperature distribution, which are directly related to geometric parameters, material properties and working pressure, are determined. This helps to better understand the thermo-elastic-plastic deformation behavior of the die and design the combined forging die to achieve long service life and high accuracy product.
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    Calculation of Electrostatic/Magnetic Adhesion Force Between Adjacent Objects Considering Thin Gap Effect
    JIANG Peng (江 鹏), LI Zhibin (李志彬), ZHANG Long (张 龙), LI Jing (李 敬), ZHANG Qun (张 群), GUAN Zhenqun∗ (关振群)
    J Shanghai Jiaotong Univ Sci    2023, 28 (2): 213-219.   DOI: 10.1007/s12204-021-2317-1
    Abstract121)      PDF (917KB)(25)      
    This paper presents a new approach to evaluating the electrostatic/magnetic adhesion force between two adjacent objects separated by a thin gap. In this approach, instead of generating mesh for the gap, a contact boundary is introduced in the finite element modeling to obtain a reasonable field distribution; then the field in the gap is approximated based on the continuity condition at their interface, so that the adhesion force can be properly calculated. Moreover, a simple equivalent circuit model is introduced to explain how the thin gap influences the adhesion force significantly. Numerical experiments are given to demonstrate the validity of the proposed method and the significance of the thin gap.
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    Enhancement of Pinching Grasping Robustness Using a Multi-Structure Soft Gripper
    LI Linlin (李林霖), GAO Feiyang (高飞扬), ZHENG Xiongfei(郑雄飞), ZHANG Liming(张黎明), LI Shijie (李世杰), WANG Heran(王赫然)
    J Shanghai Jiaotong Univ Sci    2023, 28 (3): 307-311.   DOI: 10.1007/s12204-022-2508-4
    Abstract111)      PDF (2071KB)(38)      
    Recently, soft grippers have garnered considerable interest in various fields, such as medical rehabilitation, due to their high compliance. However, the traditional PneuNet only reliably grasps medium and large objects via enveloping grasping (EG), and cannot realize pinching grasping (PG) to stably grasp small and thin objects as EG requires a large bending angle whereas PG requires a much smaller one. Therefore, we proposed a multi-structure soft gripper (MSSG) with only one vent per finger which combines the PneuNet in the proximal segment with the normal soft pneumatic actuator (NSPA) in the distal segment, allowing PG to be realized without a loss in EG and enhancing the robustness of PG due to the height difference between the distal and proximal segments. Grasping was characterized on the basis of the stability (finger bending angle describes) and robustness (pull-out force describes), and the bending angle and pull-out force of MSSG were analyzed using the finite element method. Furthermore, the grasping performance was validated using experiments, and the results demonstrated that the MSSG with one vent per finger was able to realize PG without a loss in EG and effectively enhance the PG robustness.
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