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Sliding Mode Control for Flexible-link Manipulators Based on Adaptive Neural Networks

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International Journal of Automation and computing 2018年第2期15卷 239-248页

作者： Hong-Jun Yang min tan State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences

This paper mainly focuses on designing a sliding mode boundary controller for a single flexible-link manipulator based on adaptive radial basis function （RBF） neural network. The flexible manipulator in this paper is considered to be an Euler-Bernoulli beam. We first obtain a partial differential equation （PDE） model of single-link flexible manipulator by using Hamiltons approach. To improve the control robustness, the system uncertainties including modeling uncertainties and external disturbances are compensated by an adaptive neural approximator. Then, a sliding mode control method is designed to drive the joint to a desired position and rapidly suppress vibration on the beam. The stability of the closed-loop system is validated by using Lyapunov＇s method based on infinite dimensional model, avoiding problems such as control spillovers caused by traditional finite dimensional truncated models. This novel controller only requires measuring the boundary information, which facilitates implementation in engineering practice. Favorable performance of the closed-loop system is demonstrated by numerical simulations.

关键词： Sliding mode control adaptive control neural network flexible manipulator partial differential equation (PDE).

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A hybrid deep learning and data assimilation method for model error estimation

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Science China Earth Sciences 2024年第12期67卷 3655-3670页

作者： Ziyi PENG Lili LEI Zhe-min tan Key Laboratory of Mesoscale Severe Weather Ministry of Educationand School of Atmospheric SciencesNanjing UniversityNanjing 210023China Department of Atmospheric and Oceanic Sciences Fudan UniversityShanghai 200438China

Forecast errors of numerical weather prediction consist of model errors and the growth of initial condition errors,while the initial condition is often optimized based on short-term *** it is difficult to untangle the initial condition error and model error,but it is essential to infer model errors not just for prediction but also for data assimilation(DA).A hybrid deep learning(DL)and DA method is proposed here,aiming to correct model *** uses a convolutional neural network(CNN)to extract characteristics of initial conditions and forecast errors,and then provides estimations for model *** CNN-based model error estimation method can consider the model error resulted from inaccurate model parameters,or simultaneously consider the model error and initial condition *** on the Lorenz05 model,offline and online experiments demonstrate that the CNN-based model error estimation method can effectively correct model errors resulted from inaccurate model parameters,including the forcing F,coupling coefficient c,and relative scale *** both online and offline model error estimations,simultaneously considering model errors and initial condition errors are beneficial to infer the model errors,compared to considering model errors ***,using the observations to verify the forecasts has advantages over using the analyses,to estimate the model *** observations can also achieve a faster convergence of model error estimation with online DA than using analyses.

关键词： Data assimilation Deep learning Model error

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Controlling the depth of a gliding robotic dolphin using dual motion control modes

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Science China(Information Sciences) 2020年第9期63卷 217-230页

作者： Jian WANG Zhengxing WU min tan Junzhi YU State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering ScienceBIC-ESAT College of Engineering Peking University

This paper investigates the performance of the dual mode, namely flipper mode and central pattern generator(CPG) mode, for controlling the depth of a gliding robotic dolphin. Subsequent to considering the errors in dynamic models, we propose a depth control system that combines the line-of-sight(LOS)method with an adaptive control approach(ACA) to deal with uncertainties in the model parameters. First,we establish a full-state dynamic model to conduct simulations and optimize the parameters used in later aquatic experiments. Then, we use the LOS method to transform the control target from the depth to the pitch angle and employ the ACA to calculate the control signal. In particular, we optimize the ACA’s control parameters using simulations based on our dynamic model. Finally, our simulated and experimental results demonstrate not only that we can successfully control the robotic dolphin’s depth, but also that its performance was better than that of the CPG-based control, thus indicating that we can achieve three-dimensional motion by combining flipper-based and CPG-based control. The results of this study suggest valuable ideas for practical applications of gliding robotic dolphins.

关键词： gliding robotic dolphin depth control dual motion adaptive control approach

Hydrodynamic Analysis and Verification of an Innovative Whale Shark-like Underwater Glider

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Journal of Bionic Engineering 2020年第1期17卷 123-133页

作者： Huijie Dong Zhengxing Wu min tan Junzhi Yu State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceBIC-ESATCollege of EngineeringPeking UniversityBeijing 100871China

This paper presents an innovative design for a biomimetic whale shark-like underwater glider aiming at the combination of high maneuverability and long *** a hybrid of the underwater glider and the robotic fish,its pectoral fins and tail can serve as not only the external control surfaces for attitude regulation during gliding but also the propellers for agile fish-like swimming *** verify the gliding capability of the whale shark-like glider and prepare for future dynamic analysis,the hydrodynamic coefficients,including drag,lift,sliding force,and corresponding moments are estimated through computational fluid dynamics *** addition,the hydrodynamic analyses of the proposed glider and an equivalent conventional glider during steady gliding motion are executed for *** experiments are performed to verify the downward gliding *** results reveal that the whale shark-like glider has less drag as well as higher lift-to-drag ratio and a markable gliding capability in *** may offer important inspiration for improving the gliding efficiency and performance of an underwater glider in biomimetic shape design.

关键词： biomimetic robot CFD hydrodynamic analysis underwater glider

Novel sliding-mode disturbance observer-based tracking control with applications to robot manipulators

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Science China(Information Sciences) 2021年第7期64卷 80-91页

作者： Tairen SUN Long CHENG Zengguang HOU min tan School of Electrical and Information Engineering Jiangsu University State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences School of Artificial Intelligence University of Chinese Academy of Sciences

This paper proposes a sliding-mode disturbance observer(SMDOB)-based tracking controller for a class of nonlinear systems with modeling uncertainties and external disturbances. The SMDOB is constructed using an extended state observer embedded by a filtered sliding mode term. The chattering caused by the sliding mode is compressed by the frequency bandwidths of both the extended state observer and the control system. The novelties of the proposed controller are as follows:(1) The semiglobal asymptotical stability of the combined controller-observer system is guaranteed without the boundedness assumption of the time derivatives of modeling uncertainties;(2) the SMDOB can be implemented with a low complexity because of only three parameters to be tuned. Applications to robot manipulators illustrate the effectiveness of the SMDOB-based tracking control strategy.

关键词： adaptive control robot manipulator disturbance observer sliding mode

Adaptive Decoding Algorithm Based on Multiplicity of Candidate Sequences for Block Turbo Codes

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China Communications 2014年第A01期11卷 9-15页

作者： DANG Xiaoyu tan min YU Xiangbin CollegeofElectronicInformationEngineering NanjingUniversityofAeronauticsandAstronauticsNanjing210016China

It is known that Block Turbo Codes （BTC） can be nearly optimally decoded by Chase-II algorithm, in which the Least Reliable Bits （LRBs） are chosen empirically to keep the size of the test patterns （sequences） relatively small and to reduce the decoding complexity. While there are also other adaptive techniques, where the decoder＇s LRBs adapt to the external parameter of the decoder like SNR （Signal Noise Ratio） level, a novel adaptive algorithm for BTC based on the statistics of an internal variable of the decoder itself is proposed in this paper. Different from the previous reported results, it collects the statistics of the multiplicity of the candidate sequences, i.e., the number of the same candidate sequences with the same minimum squared Euclidean distance resulted from the decoding of test sequences. It is shown by Monte Carlo simulations that the proposed adaptive algorithm has only about 0.02dB coding loss but the average complexity of the proposed algorithm is about 42% less compared with Pyndiah＇s iterative decoding algorithm using the fixed LRBs parameter.

关键词： block turbo codes adaptive algorithm least reliable bits bit error rate (BER) complexity

Parameter estimation survey for multi-joint robot dynamic calibration case study

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Science China(Information Sciences) 2019年第10期62卷 102-116页

作者： Shaolin ZHANG Shuo WANG Fengshui JING min tan The State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences University of Chinese Academy of Sciences CAS Center for Excellence in Brain Science and Intelligence Technology

Accurate model parameters are the basis of robot dynamics. Many linear and nonlinear models have been proposed to calibrate the inertial parameters and friction parameters of multi-joint ***, methods of choosing a model and calculating its parameters still have few summaries. This paper reviews typical linear/nonlinear models and different calculation methods for robot dynamic *** simulations, the features of different methods are analyzed, including torque error, parameter error, model adaptability, solution time, and anti-interference ability of the calibration results. Finally, an experiment performed on a six-degree-of-freedom industrial manipulator is used as an example to illustrate how to select the model for a specified robot. These comparisons and experiments provide references for the parameter calibration of multi-joint robots.

关键词： dynamic parameter calibration friction calibration robot dynamics industrial manipulator dynamic models

Kinematic Comparison of Forward and Backward Swimming and Maneuvering in a Self-Propelled Sub-Carangiform Robotic Fish

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Journal of Bionic Engineering 2014年第2期11卷 199-212页

作者： Zhengxing Wu Junzhi Yu min tan Jianwei Zhang State Key Laboratory of Management and Control for Complex Systems Institute of Automation Chinese Academy of Sciences Beijing 100190 P. R. China Department of Informatics University of Hamburg Hamburg Germany

We make a thorough kinematic comparison of forward and backward swimming and maneuvering on a self-propelled robot platform that uses sub-carangifbrm swimming as the primary propulsor. An improved Central Pattern Generator （CPG） model allowing free adjustment of phase relationship and directional bias is employed to achieve flexible swimming and smooth transition. Considering the characteristics of forward swimming in carangiform fish and backward swimming in anguilliform fish, various backward swimming patterns for the sub-carangiform robotic fish are suitably created by reversing the direction of propagating propulsive waves. Through a combined use of the CPG control and closed-loop swimming direction control strategy, flexible and precise turning maneuvers in both forward and backward swimming are implemented and compared. By contrast with forward swimming, backward swimming requires a higher frequency or an increased lateral displacement to reach the same relative swimming speed. Noticeably, the phase difference shows a greater impact on forward swimming than on backward swimming. Our observations also indicate that the robotic fish achieves a larger turning rate in forward maneuvering than in backward maneuvering, yet these two maneuvers display comparable turning precision.

关键词： robotic fish backward swimming Central Pattern Generator (CPG) swimming locomotion control

Snoring detection based on a stretchable strain sensor

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Science China(Information Sciences) 2021年第7期64卷 224-226页

作者： Zhengwei LI Qingkun SONG Long CHENG min tan School of Automation Harbin University of Science and Technology State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences University of Chinese Academy of Sciences

Snoring is caused by the stenosis of the upper respiratory tract, which can lead to the vibration of the palatine *** brings not only harm to the snorer [1] but also sleep deprivation to those around them [2]. Furthermore, studies show that loud snorers have a 67%greater chance of suffering from a stroke and a 34%higher risk of having a heart attack. To identify people at risk from these diseases,snoring recording and analysis become highly important [3].

关键词： Information Systems and Communication Service