Weidong Chen

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (50)34.55 Total impact

  • Yong Wang, Weidong Chen, Jingchuan Wang
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    ABSTRACT: Purpose ‐ The purpose of this paper is to propose a localizability-based particle filtering localization algorithm for mobile robots to maintain localization accuracy in the high-occluded and dynamic environments with moving people. Design/methodology/approach ‐ First, the localizability of mobile robots is defined to evaluate the influences of both the dynamic obstacles and prior-map on localization. Second, based on the classical two-sensor track fusion algorithm, the odometer-based proposal distribution function (PDF) is corrected, taking account of the localizability. Then, the corrected PDF is introduced into the classical PF with "roulette" re-sampling. Finally, the robot pose is estimated according to all the particles. Findings ‐ The experimental results show that, first, it is necessary to consider the influence of the prior-map during the localization in the high-occluded and dynamic environments. Second, the proposed algorithm can maintain an accurate and robust robot pose in the high-occluded and dynamic environments. Third, its real timing is acceptable. Research limitations/implications ‐ When the odometer error and occlusion caused by the dynamic obstacles are both serious, the proposed algorithm also has a probability evolving into the kidnap problem. But fortunately, such serious situations are not common in practice. Practical implications ‐ To check the ability of real application, we have implemented the proposed algorithm in the campus cafeteria and metro station using an intelligent wheelchair. To better help the elderly and disabled people during their daily lives, the proposed algorithm will be tested in a social welfare home in the future. Original/value ‐ The localizability of mobile robots is defined to evaluate the influences of both the dynamic obstacles and prior-map on localization. Based on the localizability, the odometer-based PDF is corrected properly.
    Industrial Robot 05/2014; 41(3). · 0.62 Impact Factor
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    ABSTRACT: In this paper, the uncalibrated fixed-camera visual servoing problem of robot manipulators will be addressed by considering its full motor dynamics. A new adaptive image-space visual servoing strategy without both the joint and visual acceleration measurements is presented, which can handle uncertainties in the camera intrinsic and extrinsic parameters, the robot kinematic and dynamic parameters, and the motor dynamic parameters. The proposed scheme is developed based on the depth-independent interaction matrix in order to deal with the nonlinear dependence of image Jacobian matrix on the unknown parameters, which allows the camera and robot kinematic parameters in the closed-loop dynamics to be linearly parameterized. In this way, adaptive laws for the online estimation of the unknown camera, kinematic, rigid dynamic, and motor dynamic parameters can be developed very efficiently. Furthermore, a joint velocity observer will also be presented to solve the problem without both the joint and visual acceleration measurements. To show asymptotic convergence of image errors, stability analysis based on both the rigid-link robot dynamics and full motor dynamics will be performed by using Lyapunov theory. Simulation results will be given to validate the performance of the proposed scheme.
    Asian Journal of Control 05/2014; 16(3). · 1.41 Impact Factor
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    ABSTRACT: This paper considers the robust stability bound problem of uncertain fractional-order systems. The system considered is subject either to a two-norm bounded uncertainty or to a infinity-norm bounded uncertainty. The robust stability bounds on the uncertainties are derived. The fact that these bounds are not exceeded guarantees that the asymptotical stability of the uncertain fractional-order systems is preserved when the nominal fractional-order systems are already asymptotically stable. Simulation examples are given to demonstrate the effectiveness of the proposed theoretical results.
    Fractional Calculus and Applied Analysis 03/2014; 17(1). · 2.97 Impact Factor
  • Yingdong Ma, Junguo Lu, Weidong Chen
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    ABSTRACT: This paper investigates the robust stability and stabilization of fractional order linear systems with positive real uncertainty. Firstly, sufficient conditions for the asymptotical stability of such uncertain fractional order systems are presented. Secondly, the existence conditions and design methods of the state feedback controller, static output feedback controller and observer-based controller for asymptotically stabilizing such uncertain fractional order systems are derived. The results are obtained in terms of linear matrix inequalities. Finally, some numerical examples are given to validate the proposed theoretical results.
    ISA Transactions 12/2013; · 2.26 Impact Factor
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    Jun-Guo Lu, Yangquan Chen, Weidong Chen
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    ABSTRACT: This paper considers the robust asymptotical stability problem of fractional-order linear systems with structured perturbations, which are more general than the investigated fractional-order interval systems. Based on the Kronecker product and @m-analysis, necessary and sufficient conditions for the robust asymptotical stability are established by transforming such a problem into checking the nonsingularity of a class of uncertain matrices. Furthermore, the robustness bounds with respect to parametric perturbations to preserve the asymptotical stability are given in terms of the structured singular values. Finally, illustrative examples are given to show the effectiveness of the proposed approach.
    Computers & Mathematics with Applications 09/2013; 66(5):873-882. · 2.00 Impact Factor
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    ABSTRACT: Aim at enhancing dexterous and safe operation in unstructured environment, a cable-driven soft robotic manipulator is designed in this paper. Due to soft material it made of and nearly infinite degree of freedom it owns, the soft robotic manipulator has higher security and dexterity than traditional rigid-link manipulator, which make it suitable to perform tasks in complex environments that is narrow, confined and unstructured. Though the soft robotic manipulator possesses advantages above, it is not an easy thing for it to achieve precise position control. In order to solve this problem, a kinematic model based on piecewise constant curvature hypothesis is proposed. Through building up three spaces and two mappings, the relationship between the length variables of 4 cables and the position and orientation of the soft robotic manipulator end-effector is obtained. Afterwards, a depth-independent image Jacobian matrix is introduced and an image-based visual servo controller is presented. Applied by adaptive algorithm, the controller could estimate unknown position of the feature point online, and then Lyapunov theory is used to prove the stability of the proposed controller. At last, experiments are conducted to demonstrate rationality and validity of the kinematic model and adaptive visual servo controller.
    Intelligent Robots and Systems (IROS), 2013 IEEE/RSJ International Conference on; 01/2013
  • Junguo Lu, Yingdong Ma, Weidong Chen
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    ABSTRACT: This paper investigates the maximal perturbation bound problem for robust stabilizability of the fractional-order system with two-norm bounded perturbations or infinity-norm bounded perturbations. Firstly, a necessary condition and several sufficient conditions for robust stabilization are derived. Secondly, linear matrix inequality approaches for computing the maximal robust stabilizability perturbation bound of such perturbed fractional-order system with a linear state feedback controller, simultaneously obtaining the corresponding linear state feedback stabilizing controller are presented. With the help of the linear matrix inequality solvers, we can easily obtain the maximal robust stabilizability perturbation bound and the corresponding linear state feedback stabilizing controller. Finally, simulation examples are given to demonstrate the effectiveness of the proposed approaches.
    Journal of the Franklin Institute 01/2013; 350(10). · 2.26 Impact Factor
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    ABSTRACT: This paper presents a new controller to regulate a set of feature points on the image plane to desired positions by controlling motion of a robot manipulator in uncalibrated environments. This controller is designed to cope with both the unknown camera parameters and the unknown robot parameters. The controller employs the depth-independent image Jacobian matrix to map the image errors onto the joint space of the manipulator. Based on the fact that the unknown camera and robot parameters appear linearly in the closed-loop dynamics of the system if the depth-independent image Jacobian is used, an adaptive algorithm was developed to estimate the unknown parameters on-line. With a full consideration of dynamic responses of the robot manipulator, the convergence of the image errors on the image plane to zero was proved by the Lyapunov method. Simulation and experiments have been conducted to demonstrate good convergence of the trajectory errors under the control of the proposed method.
    Mechatronics. 09/2012;
  • Jun-Guo Lu, Jizhong Xiao, Weidong Chen
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    ABSTRACT: In this paper, the robust αα-stability problem of matrix second-order systems with perturbations in the form of a one-parameter family of matrices is investigated. All the system matrices, including the second-order differential coefficient matrices, are assumed to have such perturbations. Based on the Kronecker product, a necessary and sufficient condition for the robust αα-stability problem is presented by transforming such a problem into checking the nonsingularity of a class of uncertain matrices. Then, a closed form for the maximal perturbation bounds for preserving the αα-stability is given. Finally, illustrative examples are given to show that our results are effective and less conservative than the results obtained by other researchers.
    Automatica 05/2012; 48(5):995–998. · 3.13 Impact Factor
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    ABSTRACT: Liquid handling plays a pivotal role in life science laboratories. In experiments such as gene sequencing, protein crystallization, antibody testing, and drug screening, liquid biosamples frequently must be transferred between containers of varying sizes and/or dispensed onto substrates of varying types. The sample volumes are usually small, at the micro- or nanoliter level, and the number of transferred samples can be huge when investigating large-scope combinatorial conditions. Under these conditions, liquid handling by hand is tedious, time-consuming, and impractical. Consequently, there is a strong demand for automated liquid-handling methods such as sensor-integrated robotic systems. In this article, we survey the current state of the art in automatic liquid handling, including technologies developed by both industry and research institutions. We focus on methods for dealing with small volumes at high throughput and point out challenges for future advancements.
    Journal of the Association for Laboratory Automation 02/2012; 17(3):169-85. · 1.50 Impact Factor
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    ABSTRACT: An actions selection mechanism for mobile robots is proposed to accelerate convergence of global localization without increasing computational complexity. In this mechanism, the localizability matrix of every pose is calculated off-line over the apriori probabilistic grid map, and during the phase of global localization with particle filtering, robot actions are selected actively according to maximization of localizability distinctness for all particles. Real robot and real world experiments are implemented for verifying the proposed approach. The experimental results show that the localizability matrix is able to represent the probability distribution of possible observations in the given map accurately, and the actions selection strategy improves the efficiency compared with standard global localization method.
    Mechatronics and Automation (ICMA), 2012 International Conference on; 01/2012
  • Jun‐Guo Lu, Jizhong Xiao, Weidong Chen
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    ABSTRACT: This paper investigates the quadratic stability and stabilization of a class of matrix second‐order time‐varying systems. All the system matrices including the second‐order differential coefficient matrix are assumed to have the time‐varying norm‐bounded parameters. Necessary and sufficient conditions for the quadratic stability and stabilization of such time‐varying systems are derived. All the results are obtained in terms of linear matrix inequalities. Two illustrative examples are given to show that our results are effective and less conservative than the results obtained by other researchers. Copyright © 2011 John Wiley & Sons, Ltd.
    International Journal of Robust and Nonlinear Control 01/2012; 22(18). · 2.65 Impact Factor
  • Zhe Liu, Weidong Chen, Yong Wang, Jingchuan Wang
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    ABSTRACT: A novel approach to estimate localizability for mobile robots is presented based on probabilistic grid map (PGM). Firstly, a static localizability matrix is proposed for off-line estimation over the priori PGM. Then a dynamic localizability matrix is proposed to deal with unexpected dynamic changes. These matrices describe both localizability index and localizability direction quantitatively. The validity of the proposed method is demonstrated by experiments in different typical environments. Furthermore, two typical localization-related applications, including active global localization and pose tracking, are presented for illustrating the effectiveness of the proposed localizability estimation method.
    Multisensor Fusion and Integration for Intelligent Systems (MFI), 2012 IEEE Conference on; 01/2012
  • Xinwu Liang, Hesheng Wang, Weidong Chen
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    ABSTRACT: In this paper, the uncalibrated visual servoing problem of robot manipulators with motor dynamics will be addressed for the fixed-camera configuration. A new adaptive image-space visual servoing strategy is presented to handle uncertainties in the camera intrinsic and extrinsic parameters, robot kinematic and dynamic parameters, and motor dynamic parameters. To deal with the nonlinear dependence of image Jacobian matrix on the unknown parameters, the proposed scheme is developed based on the concept of depth-independent interaction matrix. In this way, the camera parameters and the robot kinematic parameters in the closed-loop dynamics can be linearly parameterized such that adaptive laws can be designed to estimate them on-line. Adaptive algorithms are also developed to provide estimation of unknown robot dynamic and motor dynamic parameters. Stability analysis will be performed to show asymptotic convergence of image errors using Lyapunov theory based on both rigid-link robot dynamics and full motor dynamics. Simulation results based on a two-link planar robot manipulators will be given to illustrate the performance of the proposed scheme.
    Multisensor Fusion and Integration for Intelligent Systems (MFI), 2012 IEEE Conference on; 01/2012
  • Xinwu Liang, Hesheng Wang, Weidong Chen
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    ABSTRACT: Uncalibrated visual servoing techniques based on the depth-independent interaction matrix framework have been proposed for the general 3D motion control of robot manipulators, which can simultaneously handle both the unknown intrinsic and extrinsic camera parameters. By extending the existing adaptive eye-in-hand visual servoing approach based on the depth-independent interaction matrix, in this paper, we propose an uncalibrated dynamic visual tracking approach for the eye-in-hand camera configuration by observing multiple feature points of a static object. The proposed approach can simultaneously handle the unknown camera parameters and the unknown 3D coordinates of the feature points, where a new adaptive law is developed to estimate these unknown parameters online. On the basis of nonlinear dynamics of robot manipulators, we also prove the asymptotic convergence of the image errors with the help of Lyapunov theory. To demonstrate the performance of the proposed approach, preliminary simulation results will be given by using a two-link planar robot manipulator.
    Control Conference (CCC), 2012 31st Chinese; 01/2012
  • Qinan Li, Weidong Chen, Jingchuan Wang
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    ABSTRACT: Shared control is a common used method for human and wheelchair cooperation. However, most of the previous shared control methods didn't think much of the effect caused by the difference in the user's control ability. The control weight of a user in these methods is irrelevant to the user's capability or the driving conditions. In this paper, a dynamic shared control method is proposed to adapt wheelchair's assistance to the variations of user performance and the environmental changes. Three evaluation indices including safety, comfort and obedience are designed to evaluate wheelchair performance in real time. A minimax multi-objective optimization algorithm is adopted to calculate the user's control weight. The results of lab experiments and elderly home field tests show that this method can adapt the degree of wheelchair's autonomy to the user's control ability and it makes driving wheelchair much easier for elder people.
    Robotics and Automation (ICRA), 2011 IEEE International Conference on; 06/2011
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    ABSTRACT: This paper presents a new controller for locking a moving object in 3-D space at a particular position (for example, the center) on the image plane of a camera mounted on a robot by actively moving the camera. The controller is designed to cope with both the highly nonlinear robot dynamics and unknown motion of the object. Based on the fact that the unknown position of the moving object appears linearly in the closed-loop dynamics of the system if the depth-independent image Jacobian is used, we developed a nonlinear observer to estimate the 3-D motion of the object online. With a full consideration of dynamic responses of the robot manipulator, we employ the Lyapunov method to prove asymptotic convergence of the image errors. Experimental results are used to demonstrate the performance of the proposed approach.
    IEEE/ASME Transactions on Mechatronics 05/2011; · 3.65 Impact Factor
  • Jian Li, Weidong Chen
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    ABSTRACT: From the viewpoint of the system's mechanical energy, the passive inverted pendulum model (PIPM) is proposed for the generation of more energy-efficient biped gait pattern. The generated walking pattern, based on the PIPM, enables the fully actuated biped robots to closely mimic the behavior of stable passive walking, so that it can have good energy-efficiency, which is the inherent advantage of the passive system. Furthermore, the pattern generation method is extended to any desired terrain as well. As for SHR-1, the first-generation biped robot of Shanghai Jiao Tong University, gait synthesis is clarified in detail. Finally, the walking experiments are carried out on SHR-1, and the effectiveness of the proposed pattern generation method is confirmed.
    Robotica 01/2011; 29:595-605. · 0.88 Impact Factor
  • Hesheng Wang, Weidong Chen, Zhongli Wang
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    ABSTRACT: This paper presents a new adaptive controller for visual tracking control of a robot manipulator in 3D general motion with a fixed camera whose intrinsic and extrinsic parameters are uncalibrated. In addition to camera parameters, the feature positions in 3D space are also assumed unknown. Based on the fact that the unknown parameters appears linearly in the closed-loop dynamics of the system if the depth-independent interaction matrix is adopted to map the image errors onto the joint space of the manipulator, we developed a new adaptive algorithm to estimated the unknown parameters on-line. With a full consideration of dynamic responses of the robot manipulator, we employ the Lyapunov method to prove asymptotic convergence of the image errors. Experimental results are used to demonstrate the performance of the proposed approach.
    2011 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2011, San Francisco, CA, USA, September 25-30, 2011; 01/2011
  • Dedi Ma, Hesheng Wang, Weidong Chen
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    ABSTRACT: In order to operate unknown constrained mechanisms with assistive robot manipulators, a dynamic hybrid compliance control algorithm was proposed in the paper. The controller using the proposed algorithm was designed to estimate constrained frame, determine driving-axis and obtain control velocity. Firstly, the constrained frame was estimated online according to the previous motion direction, and a suitable direction was selected as driving-axis by selection matrix; then hybrid position/force control was adopted to decouple the driving-axis and non-driving-axis; finally, velocity control was used at the driving-axis and impedance control was used at the non-driving-axis. The proposed dynamic hybrid compliance control algorithm made manipulators find a suitable direction as the driving-axis to operate the constrained mechanisms. And the dynamic characteristics of operation were improved. The validity of the proposed method was verified by the experiments of autonomous door opening utilizing a 6-DoF manipulator.
    01/2011;

Publication Stats

115 Citations
34.55 Total Impact Points

Institutions

  • 2004–2014
    • Shanghai Jiao Tong University
      • • Department of Automation
      • • School of Electronic, Information and Electrical Engineering
      Shanghai, Shanghai Shi, China
  • 2006–2008
    • Shandong University
      • School of Control Science and Engineering
      Jinan, Shandong Sheng, China
  • 2004–2008
    • The Ohio State University
      • Department of Electrical and Computer Engineering
      Columbus, OH, United States
  • 2007
    • Shanghai University
      • Department of Automation
      Shanghai, Shanghai Shi, China