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A fast scanning strategy based on trajectory shaping for atomic force microscopy

Nano Research 2022年第7期15卷 6438-6446页

作者： Yinan Wu Yingao Chang Yongchun fang Zhi Fan Institute of Robotics and Automatic Information System College of Artificial IntelligenceNankai UniversityTianjin 300350China Tianjin Key Laboratory of Intelligent Robotics Nankai UniversityTianjin 300350China

To improve the scanning speed of an atomic force microscopy(AFM),a smooth scanning pattern is elaborately devised via trajectory shaping in this paper,so as to achieve fast imaging without hardware modification.Specifically,in the proposed scanning method,the piezoelectric actuator tracks a well-designed smooth periodic signal in x-direction,and simultaneously tracks a step signal in y-direction.The advantage of the proposed method is that it does not require additional data reprocessing to construct the morphology of the sample surface,while significantly increasing the scanning bandwidth restricted by the raster scanning method.Particularly,to directly utilize the height data collected by scanning to produce the sample morphology,the forward process in the common raster scanning mode is retained in the proposed method,the tracking signal in the forward process is thus set to a ramp function in x-direction.In addition,to ensure the continuity and smoothness of the entire tracking signal in x-direction,a segment of a sine curve is uniquely determined as the backward tracking signal by position and acceleration constraints,so as to ensure that the forward and backward curves are continuous and acceleration-continuous at the intersection point.Moreover,the frequency spectrum analysis of the designed smooth signal is carried out to exhibit the depressed amplitudes of high-frequency components,which demonstrates that the proposed method is able to reduce the resonance in AFM high-speed scanning,so as to improve the capacity of rapidly generating high-quality images.Finally,convincing comparison experiments are implemented to verify the imaging performance of the designed scanning algorithm.

关键词： atomic force microscopy fast scanning smooth signal trajectory shaping

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Neural network-based adaptive sliding mode control for underactuated dual overhead cranes suffering from matched and unmatched disturbances

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Autonomous Intelligent Systems 2022年第1期2卷 1-15页

作者： Tianci Wen Yongchun fang Biao Lu Institute of Robotics and Automatic Information System College of Artificial IntelligenceNankai UniversityTianjin300353China

To improve transportation capacity,dual overhead crane systems(DOCSs)are playing an increasingly important role in the transportation of large/heavy cargos and containers.Unfortunately,when trying to deal with the control problem,current methods fail to fully consider such factors as external disturbances,input dead zones,parameter uncertainties,and other unmodeled dynamics that DOCSs usually suffer from.As a result,dramatic degradation is caused in the control performance,which badly hinders the practical applications of DOCSs.Motivated by this fact,this paper designs a neural network-based adaptive sliding mode control(SMC)method for DOCS to solve the aforementioned issues,which achieves satisfactory control performance for both actuated and underactuated state variables,even in the presence of matched and mismatched disturbances.The asymptotic stability of the desired equilibrium point is proved with rigorous Lyapunov-based analysis.Finally,extensive hardware experimental results are collected to verify the efficiency and robustness of the proposed method.

关键词： Asymptotic stability Sliding mode control Neural networks Unmatched disturbances Underactuated system

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A novel frequency-dependent hysteresis model based on improved neural Turing machine

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Science China(Information Sciences) 2023年第1期66卷 330-331页

作者： Yinan WU Yongchun fang Zhi FAN Cunhuan LIU Institute of Robotics and Automatic Information System College of Artificial IntelligenceNankai University Tianjin Key Laboratory of Intelligent Robotics Nankai University

Dear editor,The inherent hysteresis of a piezoelectric actuator(PEA) results in intricate nonlinearity between the output displacement and input voltage, which restricts positioning accuracy of the actuator [1, 2]. Hysteresis behavior appears as a coupling of nonlinearity, frequency-dependence and memory characteristic, which makes it difficult to comprehensively characterize hysteresis [3]. To eliminate the effect of hysteresis on the positioning accuracy of PEAs,

关键词： ATOMIC-FORCE MICROSCOPY

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Adaptive Sliding-Mode Disturbance Observer-Based Nonlinear Control for Unmanned Dual-Arm Aerial Manipulator Subject to State Constraints

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Guidance, Navigation and Control 2023年第3期3卷 47-64页

作者： Bingbing Liu Hai Yu Shizhen Wu Xiao Liang Yongchun fang College of Artificial Intelligence Nankai University Tianjin 300350P.R.China

The unmanned dual-arm aerial manipulator system is composed of a multirotor unmanned aerial vehicle(UAV)and two manipulators.Compared to a single manipulator,dual-arm always provides greater°exibility and versatility in both goods delivery and complex task execution.However,the practical application of the system is limited due to nonlinearities and complex dynamic coupling behavior between the multirotor and the manipulator,as well as the one between the inner and outer loop of the multirotor.In this paper,a holistic model of the dual-arm aerial manipulator system is¯rst derived with complete model information.Subsequently,an adaptive sliding-mode disturbance observer(ASMDO)is proposed to handle external disturbances and unmeasurable disturbances caught by unmeasurable angular velocity and acceleration of the manipulators.Moreover,for safety concerns and transient performance requirements,the state constraints should be guaranteed.To this end,an auxiliary term composed of constrained variable signals is introduced.Then,the performance of the designed method is proven by rigorous analysis.Finally,the proposed method is validated through two sets of simulation tests.

关键词： Unmanned dual-arm aerial manipulator adaptive sliding-mode disturbance observer state constraint

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Adaptive tracking control of flapping wing micro-air vehicles with averaging theory

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CAAI Transactions on Intelligence Technology 2018年第1期3卷 18-27页

作者： Chen Qian Yongchun fang Institute of Robotics and Automatic Information Systems College of Computer and Control Engineering Tianjin 300353People's Republic of China Tianjin Key Laboratory of Intelligent Robotics Nankai University Tianjin 300353 People's Republic of China

An input constrained adaptive tracking controller is designed for flapping micro aerial vehicles, wherein the moving averaging filter is adopted to estimate the averaged states of the system. Specifically, in the outer loop controller, an observer is constructed to estimate the disturbances within the system. Moreover, the constrained thrust is designed to keep the frequency in a proper region so as to meet the requirement of average estimation. Then, a tracking differentiator is used to provide trackable trajectories for the inner loop. Subsequently, a new quaternion-based hybrid attitude tracking controller is designed which successfully deals with high-frequency noises and avoids possible chattering. As supported by mathematical analysis, the proposed control strategy guarantees the uniform ultimate boundedness of the closed-loop system, and it keeps the control torques within the permitted range to meet the application requirement. At last, numerical simulations are carried out to support the validity of the proposed controller, whose results are satisfactory even when the thrust and torques are saturated.

关键词：飞行器跟踪器人工智能发展现状

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Swing Suppression and Accurate Positioning Control for Underactuated Offshore Crane Systems Suffering From Disturbances

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 892-900页

作者： Tong Yang Ning Sun He Chen Yongchun fang Institute of Robotics and Automatic Information Systems(IRAIS) College of Artificial IntelligenceTianjin 300350China Tianjin Key Laboratory of Intelligent Robotics(tjKLIR) Nankai UniversityTianjin 300350China IEEE School of Artificial Intelligence Hebei University of TechnologyTianjin 300401China

Offshore cranes are widely applied to transfer largescale cargoes and it is challenging to develop effective control for them with sea wave disturbances. However, most existing controllers can only yield ultimate uniform boundedness or asymptotical stability results for the system's equilibrium point, and the state variables' convergence time cannot be theoretically guaranteed. To address these problems, a nonlinear sliding mode-based controller is suggested to accurately drive the boom/rope to their desired positions. Simultaneously, payload swing can be eliminated rapidly with sea waves. As we know, this paper firstly presents a controller by introducing error-related bounded functions into a sliding surface, which can realize boom/rope positioning within a finite time, and both controller design and analysis based on the nonlinear dynamics are implemented without any linearization manipulations. Moreover, the stability analysis is theoretically ensured with the Lyapunov method. Finally, we employ some experiments to validate the effectiveness of the proposed controller.

关键词： Boom/rope positioning offshore cranes swing elimination underactuated systems

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Trajectory planning-based control of underactuated wheeled inverted pendulum robots

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Science China(Information Sciences) 2019年第5期62卷 23-25页

作者： Dingkun LIANG Ning SUN Yiming WU Yongchun fang Institute of Robotics and Automatic Information Systems (IRAIS) Tianjin Key Laboratory of Intelligent Robotics (tj KLIR) Nankai University

Dear editor,In modern industries, underactuated mechanical systems play an important role in various fields [1–6]. The wheeled inverted pendulum robot(WIPR) is a special type of non-linear and underactuated systems with strong state coupling.Typically, such a robot comprises two actuated wheels and three to-be-controlled state variables,

关键词： Trajectory planning-based control of underactuated wheeled inverted pendulum robots Figure

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银连含漱液防治鼻咽癌放疗后急性放射性口咽黏膜炎的临床疗效观察

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中药新药与临床药理 2024年第1期35卷 141-147页

作者：方彩珊肖佩琪钟毓汪咏春张驰名周敏闫亚杰阮岩广州中医药大学第一临床医学院广东广州510405 成都中医药大学附属医院四川成都610000 广州中医药大学第一附属医院广东广州510405 中山大学附属第三医院过敏科广东广州510630 广东省中医临床研究院岭南耳鼻喉病研究所广东广州510405

目的观察银连含漱液防治鼻咽癌放疗引起的急性放射性口咽黏膜炎的临床疗效。方法将32例初次行放疗的鼻咽癌患者随机分为试验组(19例)和对照组(13例),两组在放疗、化疗的基础上,试验组予银连含漱液漱口,对照组予生理盐水漱口。观察两组... 详细信息

目的观察银连含漱液防治鼻咽癌放疗引起的急性放射性口咽黏膜炎的临床疗效。方法将32例初次行放疗的鼻咽癌患者随机分为试验组(19例)和对照组(13例),两组在放疗、化疗的基础上,试验组予银连含漱液漱口,对照组予生理盐水漱口。观察两组患者干预前后严重急性放射性口咽黏膜炎的发生率,出现口咽部不适、口咽部疼痛的时间和程度(NRS评分)、生活质量评分(QOL-NPC评分)、出现放疗毒副作用(SE-QOLNPC评分)及口干症状(SE1评分)的时间及程度。结果放疗至第6周时,试验组Ⅲ级及以上的放射性口咽黏膜炎的发生率显著低于对照组(P<0.001);放疗结束后1个月,试验组I级及以上的放射性口咽黏膜炎的发生率显著低于对照组(P<0.001)。从放疗第2周开始,试验组咽部不适NRS评分低于对照组(P<0.05);从放疗第4周开始口腔及口咽部疼痛NRS评分低于对照组(P<0.05);从放疗第5周开始试验组SE1评分高于对照组(P<0.05);在放疗结束后1个月,试验组咽部不适NRS评分、口腔及口咽部疼痛NRS评分低于对照组(P<0.001),QOL-NPC评分、SE-QOL-NPC评分和SE1评分均高于对照组(P=0.05或P<0.05)。结论鼻咽癌患者在放疗期间使用银连含漱液,可以显著减少严重的急性放射性口咽黏膜炎的发生,有效延迟和缓解急性放射性口咽黏膜炎的相关症状,提高患者放疗期间的生活质量,且在放疗结束1个月后,对急性放射性口咽黏膜炎仍有较好的疗效。

关键词：银连含漱液鼻咽癌急性放射性口咽黏膜炎临床疗效

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透析初期贫血状态与维持性血液透析患者预后的相关关系

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中华肾脏病杂志 2024年第2期40卷 85-93页

作者：方辉潘斌陈思瑜何永春瞿立辉郭琦陈江华张萍浙江大学医学院附属第一医院肾脏病中心浙江省透析质量控制中心杭州310003 浙江嘉善县第二人民医院肾内科嘉兴314000

目的分析成人维持性血液透析(maintenance hemodialysis,MHD)患者透析初期贫血状态,探究透析初期贫血状态与MHD患者早期及长期生存率的关系。方法该研究为回顾性队列研究。回顾性收集浙江省透析质量控制中心登记系统中2013年1月1日至202... 详细信息

目的分析成人维持性血液透析(maintenance hemodialysis,MHD)患者透析初期贫血状态,探究透析初期贫血状态与MHD患者早期及长期生存率的关系。方法该研究为回顾性队列研究。回顾性收集浙江省透析质量控制中心登记系统中2013年1月1日至2020年12月31日新进入MHD患者的基线人口学和临床资料,根据患者透析初期血红蛋白水平将其分为高血红蛋白组(血红蛋白≥110 g/L)、中血红蛋白组(80 g/L≤血红蛋白<110 g/L)及低血红蛋白组(血红蛋白<80 g/L),比较3组患者基线资料的差异,分析8年间MHD患者血红蛋白的变化趋势。随访终点为患者转腹膜透析、肾移植、死亡或截至2021年12月31日。早期死亡定义为MHD患者开始接受透析治疗后6个月内发生的全因死亡事件,长期死亡定义为透析6个月以上发生的全因死亡事件。Kaplan-Meier生存曲线和Log-rank检验分析患者的生存率并比较3组患者生存率的差异。采用多因素Cox回归模型分析透析初期贫血(血红蛋白<110 g/L)与MHD患者早期死亡及长期死亡风险的关系。结果该研究纳入MHD患者36216例,年龄(61.3±15.5)岁,男性22163例(61.20%),透析初期血红蛋白为(89.33±20.89)g/L,血红蛋白(≥110 g/L)达标5952例(16.43%)。低血红蛋白组12232例(33.78%),中血红蛋白组18032例(49.79%),高血红蛋白组5952例(16.43%)。3组间性别分布、年龄、慢性肾小球肾炎比例、糖尿病肾病比例、糖尿病比例、心脑血管疾病比例、肿瘤比例、临时导管比例、长期导管比例、自体动静脉内瘘比例、血肌酐、血磷、血钙、C反应蛋白、全段甲状旁腺素、血白细胞、血小板、血清白蛋白、三酰甘油和总胆固醇的差异均有统计学意义(均P<0.05)。8年间MHD患者血红蛋白水平呈逐年升高趋势,依次为(88.48±22.07)g/L、(88.52±21.43)g/L、(87.86±21.29)g/L、(88.93±20.69)g/L、(88.87±20.69)g/L、(90.03±20.47)g/L、(90.74±20.31)g/L和(90.31±20.54)g/L。MHD患者发生早期死亡2176例(6.01%),发生长期死亡6557例(18.10%)。Kaplan-Meier生存曲线分析结果显示,低血红蛋白组早期生存率显著低于高血红蛋白组(Log-rank检验,χ^(2)=57.115,P<0.001)和中血红蛋白组(Log-rank检验,χ^(2)=49.918,P<0.001);低血红蛋白组(Log-rank检验,χ^(2)=107.097,P<0.001)和中血红蛋白组(Log-rank检验,χ^(2)=47.430,P<0.001)长期生存率均显著低于高血红蛋白组。多因素Cox回归分析结果显示透析初期血红蛋白<80 g/L是MHD患者早期死亡的独立影响因素(以血红蛋白≥110 g/L为参照,HR=1.307,95%CI 1.096~1.559),而透析初期80 g/L≤血红蛋白<110 g/L和血红蛋白<80 g/L(以血红蛋白≥110 g/L为参照,分别HR=1.108,95%CI 1.021~1.203;HR=1.228,95%CI 1.127~1.339)是MHD患者长期死亡的独立影响因素。结论MHD患者透析初期血红蛋白达标率较低,透析初期血红蛋白<80 g/L为MHD患者早期死亡的独立危险因素,透析初期血红蛋白<110 g/L是MHD患者长期死亡的独立危险因素。

关键词：贫血肾透析预后死亡危险因素

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Super-resolution imaging reveals the subcellular distribution of dextran at the nanoscale in living cells

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Chinese Chemical Letters 2022年第4期33卷 1865-1869页

作者： Huimin Chen Han Wang yongchun Wei Maomao Hu Bo Dong Hongbao fang Qixin Chen Institute of Materia Medica Shandong First Medical University&Shandong Academy of Medical SciencesJi’nan 250062China Department of Cardiology Shandong Provincial Hospital Affiliated to Shandong UniversityJi’nan 250012China State Key Laboratory of Coordination Chemistry Chemistry and Biomedicine Innovation Center(ChemBIC)School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Theranostic visualization of dextran at the nanoscale is beneficial for understanding the bioregulatory mechanisms of this molecule. In this study, we applied structured illumination microscopy(SIM) to capture the distribution of Cy5-Dextran at different incubation periods in living cells. The results showed that Cy5-Dextran could be absorbed by He La cells. In addition, we clarified that Cy5-Dextran exhibited differential organelle distribution(lysosomal or mitochondrial) in a time-dependent manner. Moreover,lysosomal Cy5-Dextran localization was found to be independent of the autophagy process, while Cy5-Dextran localized to the mitochondria triggered a pro-apoptotic event, upregulating the levels of reactive oxygen species(ROS) to accelerate mitochondrial fragmentation. This work uses a visualized strategy to reveal the anti-tumor bioactivity of dextran, which was achieved by regulating apoptosis and autophagy.

关键词： Dextran Subcellular distribution Super-resolution imaging Structured illumination microscopy

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