期刊文献+
共找到805篇文章
< 1 2 41 >
每页显示 20 50 100
Trade credit financing for supply chain coordination under financial challenges:a multi‑leader–follower game approach
1
作者 Faranak Emtehani Nasim Nahavandi Farimah Mokhatab Rafiei 《Financial Innovation》 2023年第1期131-169,共39页
This study is designed to solve supply chain inefficiencies caused by some members’financial problems,such as capital shortages and financing restrictions in a stochastic environment.To this end,we have established a... This study is designed to solve supply chain inefficiencies caused by some members’financial problems,such as capital shortages and financing restrictions in a stochastic environment.To this end,we have established a supply chain finance framework by designing two novel coordinating contracts based on trade credit financing for different problem settings.These contracts are modeled in the form of multi-leader Stackelberg games that address horizontal and vertical competition in a supply chain consisting of multiple suppliers and a financially constrained manufacturer.However,previous studies in the trade credit literature have addressed only simple vertical competition,that is,seller-buyer competition.To solve the proposed models,two algorithms were developed by combining population-based metaheuristics,the Nash-domination concept,and the Nikaido-Isoda function.The results demonstrate that the proposed supply chain finance framework can eliminate supply chain inefficiencies and make a large profit for suppliers,as well as the financially constrained manufacturer.Furthermore,the results of the contracts’analysis showed that if the manufacturer is required to settle its payments to suppliers before the end of the period,the trade credit contract cannot coordinate the supply chain because of a lack of incentive for suppliers.However,if the manufacturer is allowed to extend its payments to the end of the period,the proposed trade credit financing contract can coordinate the supply chain.Finally,the sensitivity analysis results indicate that the worse the financial status of the manufacturer,the more bargaining power suppliers have in determining the contract parameters for more profit. 展开更多
关键词 Supply chain coordination Financial constraint Multi-leader–follower Stackelberg game Trade credit financing Population-based metaheuristics
下载PDF
Multi-circular formation control with reinforced transient profiles for nonholonomic vehicles:A path-following framework
2
作者 Jintao Zhang Xingling Shao +1 位作者 Wendong Zhang Zongyu Zuo 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期278-287,共10页
This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the fe... This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution. 展开更多
关键词 Multi-circular formation Reinforced transient profiles Nonholonomic vehicles Path following
下载PDF
A Novel Prescribed-Performance Path-Following Problem for Non-Holonomic Vehicles
3
作者 Zirui Chen Jingchuan Tang Zongyu Zuo 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第6期1476-1484,共9页
The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlle... The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled vehicle.In this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol approach.Furthermore,the interdependence among the pre-scribed parameters is discussed.To validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach. 展开更多
关键词 Guiding vector field non-holonomic vehicle path following prescribed performance sliding mode control
下载PDF
Visual object-oriented application for lane following on intelligent highway system
4
作者 王春燕 王炜 +1 位作者 陆建 常玉林 《Journal of Southeast University(English Edition)》 EI CAS 2003年第2期165-167,共3页
A visual object-oriented software for lane following on intelligent highway system (IHS) is proposed. According to object-oriented theory, 3 typical user services of self-check, transfer of human driving and automatic... A visual object-oriented software for lane following on intelligent highway system (IHS) is proposed. According to object-oriented theory, 3 typical user services of self-check, transfer of human driving and automatic running and abnormal information input from the sensors are chosen out. In addition, the functions of real-time display, information exchanging interface, determination and operation interweaving in the 3 user services are separated into 5 object-oriented classes. Moreover, the 5 classes are organized in the visual development environment. At last, experimental result proves the validity and reliability of the control application. 展开更多
关键词 intelligent transportation system intelligent highway system lane following visual object-oriented application
下载PDF
MICROPROCESSOR BASED MODEL FOLLOWING ADAPTIVE CONTROL SYSTEM FOR CSIM DRIVES
5
作者 张春明 左敦稳 王珉 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第2期40+35-39,共6页
A model following adaptive control system for CSIM is presented in this paper. A dynamic mathematical model of slip control based system is obtained. With the help of model reducing technique, full order model is ... A model following adaptive control system for CSIM is presented in this paper. A dynamic mathematical model of slip control based system is obtained. With the help of model reducing technique, full order model is reduced to simplify the design without degrading much of the performance. Model following adaptive control laws in discrete form are derived. These laws satisfy the hyperstability condition for taking care of the load and machine parameter changes of the drive. A microprocessor 8098 is used to develop the speed controller. The implementation of the control system uses only available variables of the reference model and the controlled plant. Experimental results are given to demonstrate the good performance of the system. 展开更多
关键词 induction motors frequency converters microprocessors adaptive control model following
下载PDF
Long term efficacy of plasma derived hepatitis B vaccine among Chinese children: a 12 year follow up study 被引量:9
6
作者 LIAO Su Su 1, LI Rong Cheng 2, LI Hui 1, YANG Jin Ye 2, ZENG Xian Jia 1, GONG Jian 2, WANG Shu Sheng 2, LI Yan Ping 2 and ZHANG Kong Lai 1 《World Journal of Gastroenterology》 SCIE CAS CSCD 1999年第2期77-78,共2页
INTRODUCTIONToevaluatelongtermeficacyofaplasmaderivedhepatitisBvaccineandprovideevidencefordecisionmakingont... INTRODUCTIONToevaluatelongtermeficacyofaplasmaderivedhepatitisBvaccineandprovideevidencefordecisionmakingonthevaccineboost... 展开更多
关键词 HEPATITIS B vaccines HEPATITIS B VIRUS HBsAg follow up STUDY
下载PDF
Adaptive sliding-mode path following control system of the underactuated USV under the influence of ocean currents 被引量:10
7
作者 CHEN Xiao LIU Zhong +2 位作者 ZHANG Jianqiang ZHOU Dechao DONG Jiao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第6期1271-1283,共13页
The path-following control of the asymmetry underactuated unmanned surface vehicle(USV) under external disturbances such as unknown constant and irrational ocean currents is discussed, and an adaptive sliding-mode pat... The path-following control of the asymmetry underactuated unmanned surface vehicle(USV) under external disturbances such as unknown constant and irrational ocean currents is discussed, and an adaptive sliding-mode path-following control system is proposed, which comprises a path-variable updated law,a modified integral line-of-sight(ILOS) guidance law based on a time-varying lookahead distance and adaptive feedback linearizing controllers combined with sliding-mode technique. A more accurate USV model without the assumption of having diagonal inertia and damping matrices is first presented, aiming at improving the performance of the path-following control. Next, the coordinate transformation is adopted to decouple the sway dynamic from the rudder angle, and the path-following errors dynamics without non-singular problem are presented in the moving Frenet-Serret frame. Then, based on the cascaded theorem and the adaptive sliding-mode method, the adaptive control law of position errors and course error are designed, among which the lookahead distance and integral gain are all computed as different functions of cross-track error to estimate and compensate the sideslip angle caused by external disturbances adaptively. Finally, according to the Lyapunov and cascaded theorem, the control system proposed is proved to be uniform globally asymptotic stability(UGAS) and uniform semiglobal exponential stability(USGES) when the control objectives are all achieved. Simulation results illustrate the precision and high-quality performance of this new controller. 展开更多
关键词 sliding-mode control unmanned surface vehicle(USV) integral line-of-sight(ILOS) path following proof of stability
下载PDF
Path Following Control of A Deep-Sea Manned Submersible Based upon NTSM 被引量:7
8
作者 马岭 崔维成 《China Ocean Engineering》 SCIE EI 2005年第4期625-636,共12页
In this paper, a robust path following control law is proposed for a deep-sea manned submersible maneuvering along a predeterminated path. Developed in China, the submersible is underactuated in the horizontal plane i... In this paper, a robust path following control law is proposed for a deep-sea manned submersible maneuvering along a predeterminated path. Developed in China, the submersible is underactuated in the horizontal plane in that it is actuated by two perpendicular thrusts in this plane. The advanced non-singular terminal sliding mode (NTSM) is implemented for the design of the path following controller, which can ensure the convergence of the motion system in finite time and improve its robustness against parametric uncertainties and environmental disturbances. In the process of controller design, the close-loop stability is considered and proved by Lyapunov' s stability theory. With the experimental data, numerical simulations are provided to verify the control law for path following of the deep-sea manned submersible. 展开更多
关键词 path following deep-sea manned submersible terminal sliding mode control ROBUSTNESS
下载PDF
Impact of switching from ranibizumab to aflibercept on the number of intravitreous injection and follow up visit in wet AMD:results of real life ELU study 被引量:5
9
作者 Frederic Queguiner Kristina Bezirganyan +3 位作者 Jean Christophe Courjaret Laurence Curel Guillaume Penaranda Maud Righini Chossegros 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2020年第2期252-256,共5页
●AIM:To study if one of the two molecules could lead to a lower number of follow up visits and intra-vitreous injection(IVI)with the same efficacy.●METHODS:ELU(or"elected"in French)study is a retrospective... ●AIM:To study if one of the two molecules could lead to a lower number of follow up visits and intra-vitreous injection(IVI)with the same efficacy.●METHODS:ELU(or"elected"in French)study is a retrospective study conducted in real life in patients presenting suboptimal response after ranibizumab IVI(phase 1)and secondary switched to aflibercept(phase 2).The number of follow up visits and IVI were compared in both phases.Visual acuity(VA)evolution and"switching"reasons were secondary analyzed.●RESULTS:We retrospectively included data of 33 patients(38 eyes)with age-related macular degeneration(AMD;mean age:77±7.7 y).The number of monthly follow up visits[median(Q1;Q3)]:was significantly lower with aflibercept(phase 2),respectively 1.0(0.81;1.49)visits in phase 1,versus 0.79(0.67;0.86)visits in phase 2.The median number of monthly IVI also significantly decreased in phase 2,respectively 0.67(0.55;0.90)IVI in phase 1,versus 0.55(0.45;0.67)IVI in phase 2.The mean VA evolution(VA final-VA initial)was similar in both phases,(P>0.05).Whatever the reason for"switching"(loss of efficacy,tachyphylaxis,tolerance problems),there was no incidence on VA evolution over the time.●CONCLUSION:Our results show that switching from ranibizumab to aflibercept in"suboptimal"patients significantly reduce the number of follow up visits and IVI,with a comparable efficacy.This decrease in visit number could improve patients’quality of life and reduce surgical risk by reducing the number of injections. 展开更多
关键词 wet age-related macular degeneration ANTI-VEGF AFLIBERCEPT RANIBIZUMAB follow up visit intravitreal injection visual acuity
下载PDF
Somatostatin receptor scintigraphy in the follow up of neuroendocrine neoplasms of appendix 被引量:2
10
作者 Jelena Saponjski Djuro Macut +4 位作者 Dragana Sobic-Saranovic Sanja Ognjanovic Ivana Bozic Antic Djordje Pavlovic Vera Artiko 《World Journal of Clinical Cases》 SCIE 2020年第17期3697-3707,共11页
BACKGROUND Neuroendocrine tumors of appendix(ANETs)known as carcinoids,are rare endocrine neoplasms originated from enterochromaffin cells of gastrointestinal tract.ANETs are the third most frequent(16.7%)gastrointest... BACKGROUND Neuroendocrine tumors of appendix(ANETs)known as carcinoids,are rare endocrine neoplasms originated from enterochromaffin cells of gastrointestinal tract.ANETs are the third most frequent(16.7%)gastrointestinal neuroendocrine tumors,with the incidence of 0.08-0.2 cases/100000 during one year.Incidental ANETs occur in 0.2%-0.7%of emergency surgical resections because of suspected appendicitis which is usually the first manifestation of ANET.Although there are a lot of papers about application of somatostatin receptor scintigraphy in gastrointestinal neuroendocrine tumors,there are very rare sporadic cases described about ANETs particularly.AIM To establish the role of somatostatin receptor scintigraphy(SRS)in the management of patients with neuroendocrine tumors of appendix(ANET).METHODS The total of 35 patients was investigated,23 females and 12 males,average age(43.7±17.3 years).All patients had histological diagnosis of ANET(34 carcinoids of appendix and one tubular carcinoid).Majority of tumors have been found incidentally during surgery of:Acute appendicitis(n=15),perforated appendicitis(n=2),ileus(n=3),hysterectomy(n=3),ruptured ovarian cyst(n=2),caecal volvulus(n=1),while 9 patients had diagnosis of appendiceal tumor before the surgery.Seventeen patients had tumor grade(G)G1,12 G2 and 6 G3.The right hemicolectomy was performed in 13,while the rest of the patients had appendectomy only.SRS was done early(2 h)and late(24 h)after i.v.application of 740 MBq technetium-99 m ethylenediamine-N,N’-diacetic acid Hydrazinonicotinyl-Tyr3-Octreotide(technetium-99 m-Tektrotyd,Polatom,Poland).SRS was performed for restaging in all the patients after surgery.RESULTS There were 12 true positive(TP),19 true negative,3 false positive and 1 false negative SRS result.Sensitivity of the method was 92.31%,specificity was 86.36%,positive predictive value was 80.00%,negative predictive value was 95.00%and accuracy 88.57%.Receiver operating characteristics analysis showed that SRS scintigraphy is a good test for detection TP cases[area under the curve of 0.850,95%confidence interval(CI):0.710-0.990,P<001].Single photon emission computed tomography contributed diagnosis in 7 TP findings.In 10 patients Krenning score was 4 and in 2 was 3.In 8 patients SRS significantly changed the management of the patients(in two surgery was repeated,in 4 somatostatin analogues and in two peptide receptor radionuclide therapy).Median progression-free survival in SRS positive patients was 52 months(95%CI:39.7-117.3 mo)while in SRS negative patients it was 60 months(95%CI:42.8-77.1 mo),without statistically significant difference between the two groups(P=0.434).CONCLUSION In conclusion,our results confirmed the value of SRS in the follow-up of the patients with ANET after surgery,if recurrences or metastases are suspected. 展开更多
关键词 Somatostatin receptor scintigraphy CARCINOID APPENDIX follow up Nuclear medicine RADIONUCLIDE
下载PDF
A Mode-Switching Motion Control System for Reactive Interaction and Surface Following Using Industrial Robots 被引量:2
11
作者 Danial Nakhaeinia Pierre Payeur Robert Laganière 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第3期670-682,共13页
This work proposes a sensor-based control system for fully automated object detection and exploration(surface following) with a redundant industrial robot. The control system utilizes both offline and online trajector... This work proposes a sensor-based control system for fully automated object detection and exploration(surface following) with a redundant industrial robot. The control system utilizes both offline and online trajectory planning for reactive interaction with objects of different shapes and color using RGBD vision and proximity/contact sensors feedback where no prior knowledge of the objects is available. The RGB-D sensor is used to collect raw 3D information of the environment. The data is then processed to segment an object of interest in the scene. In order to completely explore the object, a coverage path planning technique is proposed using a dynamic 3D occupancy grid method to generate a primary(offline) trajectory. However, RGB-D sensors are very sensitive to lighting and provide only limited accuracy on the depth measurements. Therefore, the coverage path planning is then further assisted by a real-time adaptive path planning using a fuzzy self-tuning proportional integral derivative(PID)controller. The latter allows the robot to dynamically update the 3D model by a specially designed instrumented compliant wrist and adapt to the surfaces it approaches or touches. A modeswitching scheme is also proposed to efficiently integrate and smoothly switch between the interaction modes under certain conditions. Experimental results using a CRS-F3 manipulator equipped with a custom-built compliant wrist demonstrate the feasibility and performance of the proposed method. 展开更多
关键词 Adaptive control fuzzy-PID controller manipulator control motion planning surface following
下载PDF
Imaging of benign and malignant cystic pancreatic lesions and a strategy for follow up 被引量:1
12
作者 Priya Bhosale Aparna Balachandran Eric Tamm 《World Journal of Radiology》 CAS 2010年第9期345-353,共9页
Cystic lesions in a variety of organs are being increasingly recognized as an incidental finding on cross-sectional imaging.These lesions can be benign,premalignant or malignant.When these cystic lesions are small it ... Cystic lesions in a variety of organs are being increasingly recognized as an incidental finding on cross-sectional imaging.These lesions can be benign,premalignant or malignant.When these cystic lesions are small it can be difficult to characterize them radiologically.However,with appropriate clinical history and knowledge of typical imaging features of cystic pancreatic lesions this can enable accurate diagnosis and thus guide appropriate treatment.In this review,we provide an overview of the most common types of cystic lesions and their appearance on computer tomography,magnetic resonance imaging and ultrasound.We will also discuss the follow up and management strategies of these cystic lesions. 展开更多
关键词 CYSTIC PANCREATIC LESIONS follow up management IMAGING
下载PDF
Breast Cancer Survivor’s Views on Duration of Follow Up 被引量:2
13
作者 Jasim Amin Michael McKirdy 《Advances in Breast Cancer Research》 2013年第2期15-18,共4页
Background: Breast cancer is one of the commonest cancers in women in the UK and western countries [1]. Follow ups after breast cancer diagnosis is usual practice, but there is no agreed consensus among breast care pr... Background: Breast cancer is one of the commonest cancers in women in the UK and western countries [1]. Follow ups after breast cancer diagnosis is usual practice, but there is no agreed consensus among breast care providers on frequency or duration of follow up after diagnosis and adjuvant treatment. The aim of this study is to find out women’s views on the period of the clinical follow up after breast cancer diagnosis. Method: This was a surveillance study in Greenock and Glasgow in the UK (Between September 2009 and December 2010). The study group comprised of 446 Women, 246 with the history of breast cancer diagnosed 1 - 10 years, (median 4.2 years) were asked to complete a questionnaire about their views of preferred duration of follow up while they were waiting for the annual review at a breast clinic, the same questionnaire was completed by 200 women with no history of breast cancer. Results: Between September 2009 and December 2010, 246 patients were included in the study. 40% of patients were within the first three years of follow up, 27% between the 4th and 6th year and 33% were in follow-up for more than 6 years. 63% of cancer survivors think that, 10 years of follow up is necessary for reassurance, detection and treatment of any new, recurrent or spread of their breast cancer. 14% and 22% of women with a history of breast cancer preferred 3 and 5 years review by trained Radiologist/GP respectively. Women without a history of breast cancer were different in their thoughts about follow up after breast cancer: 10%, 25%, and 30% chosen 10, 5 and 3 years, 35% preferred don’t know the answer. Conclusion: Follow up programs for breast cancer survivors need to be organized, evidence based, flexible and patient tailored. Patients’ views should be taken into account when considering provision of follow-up care for breast cancer patients. 展开更多
关键词 BREAST Cancer follow up SURVIVORS View CLINIC
下载PDF
Coordinated control between a grid forming inverter and grid following inverters suppling power in a standalone microgrid 被引量:1
14
作者 Junichi Arai Yasuhiro Taguchi 《Global Energy Interconnection》 EI CAS CSCD 2022年第3期259-265,共7页
Battery energy storage systems,fuel cells,and photovoltaic generators are being adopted in distribution networks to achieve CO;emission reduction.These power sources require inverters to connect to AC networks.However... Battery energy storage systems,fuel cells,and photovoltaic generators are being adopted in distribution networks to achieve CO;emission reduction.These power sources require inverters to connect to AC networks.However,sub-networks,such as a microgrids containing inverter power sources,may be disconnected from the utility network and operated in a standalone mode during extended blackouts.This study focuses on a standalone microgrid supplied by inverter power sources without a synchronous generator and proposes a new microgrid inverter control.In this inverter control,a single grid forming inverter is operated as a master power source to determine frequency and voltage,and other inverters,called grid following inverters,are operated as subordinate power sources with active and reactive power control.The necessary functions in the energy management system are examined,and the coordinated operation of all inverters in the microgrid is demonstrated via simulation. 展开更多
关键词 Inverter control MICROGRID Standalone operation Energy management system Grid forming inverter Grid following inverter
下载PDF
Numerical Simulation for Remediation Planning for 1,4-Dioxane-Contaminated Groundwater at Kuwana Illegal Dumping Site in Japan Based on the Concept of Verified Follow Up 被引量:1
15
作者 Ramrav Hem Toru Furuichi +1 位作者 Kazuei Ishii Yu-Chi Weng 《Journal of Water Resource and Protection》 2013年第7期699-708,共10页
At Kuwana illegal dumping site in Japan, where hazardous waste was illegally dumped, groundwater was severely contaminated by Volatile Organic Compounds (VOCs). Groundwater was already remedied by conducting Pump-and-... At Kuwana illegal dumping site in Japan, where hazardous waste was illegally dumped, groundwater was severely contaminated by Volatile Organic Compounds (VOCs). Groundwater was already remedied by conducting Pump-and-Treat (P&T) after containment of all the waste by vertical slurry walls from 2002 to 2007. However, 1,4-dioxane was detected in both waste and groundwater outside of slurry walls after it was newly added into Japan environmental standards in late 2009, which suggested that the walls did not contain 1,4-dioxane completely. Our previous study developed a model to predict the 1,4-dioxane distribution in groundwater after the previous remediation at the site. In this study, numerical simulation was applied for remediation planning at the site based on the concept of Verified Follow Up (VF-UP) that had been proposed as a new approach to complete remediation effectively with consideration of future risks. The amount of waste to be removed and pumping plans were discussed by numerical simulation to achieve the remedial objective in which 1,4-dioxane in groundwater outside of walls is remedied within 10 years and 1,4-dioxane spreading throughout the walls is prevented in the case where a portion of waste is remained. Firstly, the amount of waste to be removed considering pumping plans for P&T was determined by scenario analysis. As a result, at least two-third of waste should be removed by combining with P&T. However, if the waste is remained, future risks of 1,4-dioxane spreading through the slurry walls may occur. Our simulation suggested that groundwater within the remaining waste must be pumped up at least 20 m3/d for containment of 1,4-dioxane within the remaining waste. In conclusion, our numerical simulation determined the amount of waste to be removed and the pumping plans for P&T to achieve the remedial objective effectively considering future risks based on the concept of VF-UP. 展开更多
关键词 REMEDIATION PLANNING Numerical Simulation Verified follow up Pump-and-Treat 1 4-Dioxane-Contaminated Groundwater ILLEGAL DUMPING Site
下载PDF
PREDICTIVE CONTROL FOR OPTIMAL PATH TERRAIN FOLLOWING SYSTEM 被引量:1
16
作者 Xiao Shunda Northwestern Polytechnical University Chen Bengang Leihua Electronic Technology Research Institute 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1991年第3期305-311,共7页
In this paper output predictive algorithm is applied to the design of predictive controller for an optimal path terrain following system. In this way, the error of path tracking is decreased to a minimum degree simply... In this paper output predictive algorithm is applied to the design of predictive controller for an optimal path terrain following system. In this way, the error of path tracking is decreased to a minimum degree simply and efficiently and the computation time for the optimal path is shortened greatly. Therefore, the real-time processing of the optimal path terrain following system is made to be very helpful. 展开更多
关键词 PREDICTIVE CONTROL FOR OPTIMAL PATH TERRAIN followING system
下载PDF
Finite-Time Sideslip Differentiator-Based LOS Guidance for Robust Path Following of Snake Robots 被引量:3
17
作者 Yang Xiu Dongfang Li +5 位作者 Miaomiao Zhang Hongbin Deng Rob Law Yun Huang Edmond Q.Wu Xin Xu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第1期239-253,共15页
This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance ... This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance method are proposed to counteract sideslip drift caused by cross-track velocity.The proposed differentiator can accurately observe the cross-track error and sideslip angle for snake robots to avoid errors caused by calculating sideslip angle approximately.In our method,the designed piecewise auxiliary function guarantees the finite-time stability of position errors.Secondly,for the case of external disturbances and state constraints,a Barrier Lyapunov functionbased backstepping adaptive path following controller is presented to improve the robot’s robustness.The uniform ultimate boundedness of the closed-loop system is proved by analyzing stability.Additionally,a gait frequency adjustment-based virtual velocity control input is derived to achieve the exponential convergence of the tangential velocity.At last,the availability and superiority of this work are shown through simulation and experiment results. 展开更多
关键词 Line-of-sight(LOS) path following SIDESLIP snake robot
下载PDF
Constrained Moving Path Following Control for UAV With Robust Control Barrier Function 被引量:1
18
作者 Zewei Zheng Jiazhe Li +1 位作者 Zhiyuan Guan Zongyu Zuo 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第7期1557-1570,共14页
This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with re... This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with respect to the inertial frame,while the path following error is not expected to violate the predefined boundaries.Differently from existing moving path following guidance laws,the proposed method removes complex geometric transformation by formulating the moving path following problem into a second-order time-varying control problem.A nominal moving path following guidance law is designed with disturbances and their derivatives estimated by high-order disturbance observers.To guarantee that the path following error will not exceed the prescribed bounds,a robust control barrier function is developed and incorporated into controller design with quadratic program based framework.The proposed method does not require the initial position of the UAV to be within predefined boundaries.And the safety margin concept makes error-constraint be respected even if in a noisy environment.The proposed guidance law is validated through numerical simulations of shipboard landing and hardware-in-theloop(HIL)experiments. 展开更多
关键词 Moving path following(MPF) robust control barrier function safety margin shipboard landing unmanned aerial vehicle(UAV)
下载PDF
RELATIVE NONSYMMETRY EFFECTS OF THE SUPER (GENERALIZED) NONLINEAR VELOCITY,TIME OF A PARTICLE AND ITS KINETIC FORMULAE FOR FOLLOWED BODY
19
作者 杨文熊 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1999年第3期276-281,共6页
In the paper, it has been described the relative nonsymmetry effects of the super (generalized) nonlinear velocity, time of a particle and its kinetic formulae far the followed body when it moves with high velocity. T... In the paper, it has been described the relative nonsymmetry effects of the super (generalized) nonlinear velocity, time of a particle and its kinetic formulae far the followed body when it moves with high velocity. The nonsymmetry effects can explain the problem appearing in the extention of the life time for the secondary cosmic ray, mu mesons; they also can explain the controversial problem who is more young in the famous twin paradox. Finally, the followed body kinetic formulae for the particle have been founded. 展开更多
关键词 super nonlinear velocity relative nonsymmetry twin paradox mu meson followed body
下载PDF
LSTM-DPPO based deep reinforcement learning controller for path following optimization of unmanned surface vehicle 被引量:1
20
作者 XIA Jiawei ZHU Xufang +1 位作者 LIU Zhong XIA Qingtao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第5期1343-1358,共16页
To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal po... To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal policy opti-mization(DPPO)algorithm,which is a modified actor-critic-based type of reinforcement learning algorithm,is adapted to improve the controller performance in repeated trials.The LSTM network structure is introduced to solve the strong temporal cor-relation USV control problem.In addition,a specially designed path dataset,including straight and curved paths,is established to simulate various sailing scenarios so that the reinforcement learning controller can obtain as much handling experience as possible.Extensive numerical simulation results demonstrate that the proposed method has better control performance under missions involving complex maneuvers than trained with limited scenarios and can potentially be applied in practice. 展开更多
关键词 unmanned surface vehicle(USV) deep reinforce-ment learning(DRL) path following path dataset proximal po-licy optimization long short-term memory(LSTM)
下载PDF
上一页 1 2 41 下一页 到第
使用帮助 返回顶部