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Wei Z.,Shanghai JiaoTong University | Wei Z.,State Key Laboratory of Robotics and System HIT | Chen W.,Shanghai JiaoTong University | Chen W.,State Key Laboratory of Robotics and System HIT | And 2 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

The previous perception and control system of smart wheelchairs normally doesn't distinguish different objects and treats all objects as obstacles. Consequently it is hard to realize the object related navigation tasks such as furniture docking or door passage with interference from the obstacle avoidance behavior. In this article, a local 3D semantic map is built online using a low-cost RGB-D camera, which provides the semantic and geometrical data of the recognized objects to the shared control modules for user intention estimation, target selection, motion control, as well as parameters adjusting of weight optimization for addressing different target. With the object information provided by 3D semantic map, our control system can choose different behaviors according to user intention to implement object related navigation. A smart wheelchair prototype equipped with a Kinect is developed and tested in real environment. The experiments showed that the 3D semantic map-based shared control can effectively enhance the smart wheelchair's mobility, and improve the collaboration between the user and the smart wheelchair. © Springer-Verlag Berlin Heidelberg 2012.


Wang H.,Shanghai JiaoTong University | Wang H.,State Key Laboratory of Robotics and System HIT | Jiang M.,Shanghai JiaoTong University | Chen W.,Shanghai JiaoTong University | And 2 more authors.
Mechatronics | Year: 2012

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. © 2011 Elsevier Ltd. All rights reserved.


Wang H.,Shanghai JiaoTong University | Wang H.,State Key Laboratory of Robotics and System HIT | Liu Y.-H.,Chinese University of Hong Kong | Chen W.,Shanghai JiaoTong University | Chen W.,State Key Laboratory of Robotics and System HIT
Mechatronics | Year: 2012

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 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, a new adaptive algorithm was developed to estimated the unknown parameters on-line. With a full consideration of dynamic responses of the robot manipulator, the Lyapunov method is employed to prove asymptotic convergence of the image errors. Simulation and experiment results are used to demonstrate the performance of the proposed approach. © 2011 Elsevier Ltd. All rights reserved.


Li Q.,Shanghai JiaoTong University | Li Q.,State Key Laboratory of Robotics and System HIT | Chen W.,Shanghai JiaoTong University | Chen W.,State Key Laboratory of Robotics and System HIT | And 2 more authors.
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2011

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. © 2011 IEEE.


Wang Y.,Shanghai JiaoTong University | Wang Y.,State Key Laboratory of Robotics and System HIT | Chen W.,Shanghai JiaoTong University | Chen W.,State Key Laboratory of Robotics and System HIT
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2011

A navigation system based on hybrid map for intelligent wheelchair is presented. The system is consisted of hybrid map building, localization, path planning and trajectory following. The hybrid map includes a series of small probabilistic grid maps (PGM) and a global topological map (GTM). They are built simultaneously and easily using the human-guided method. Then on the hybrid map, the localization and the real-time path planning algorithms are realized smartly and effectively. The experiments and applications results show that the human-guided method integrates both the computer's modeling ability and the human's sensory perception to the environment. The hybrid map is easy to solve the loop-closure and doorway problems that enhances the robustness against uncertainty of sensors. It also can improve the efficiency in large-scale SLAM. Further more, at an elderly home we did the activities of daily living (ADL) testing and at Shanghai Expo 2010 we demonstrated the wheelchair system by offering trial rides to visitors. © 2011 IEEE.


Zhao L.,Beihang University | Jia Y.,Beihang University | Jia Y.,State Key Laboratory of Robotics and System HIT
Neurocomputing | Year: 2016

This paper investigates the distributed attitude synchronization control of spacecraft formation flying (SFF) in the presence of unknown external disturbances. A novel multi-spacecraft modified fast terminal sliding mode (MFTSM) is designed, which not only avoids the singularity problem, but also contains the advantages of fast terminal sliding mode (FTSM). Based on the MFTSM and neutral network (NN) approximation techniques, a distributed MFTSM control law with adaptive tuning law is proposed. Moreover, a distributed MFTSM control law considering input constraint is also given. Both the two control laws can guarantee the attitude tracking errors that converge to the regions containing the origin in finite time and are independent on the precise knowledge of inertia matrix. Simulation results are presented to demonstrate the effectiveness of designed schemes. © 2015 Elsevier B.V.


Chen Y.,State Key Laboratory of Robotics and System HIT | Chen Y.,Shandong University | Li B.,State Key Laboratory of Robotics and System HIT | Li B.,Harbin Institute of Technology
Scientia Iranica | Year: 2011

Triangular Intuitionistic Fuzzy Numbers (TIFNs) express more abundant and flexible information than Triangular Fuzzy Numbers (TFNs). The main purpose of this paper is to propose a Dynamic MultiAttribute Decision Making (DMADM) model on the basis of TIFNs, to solve the DMADM problem, where all the decision information takes the form ofTlFNs. A new distance measure between two TIFNs is developed to aid in determining attribute weights, using the entropy method. An aggregation operator, the weighted arithmetic averaging operator on TIFNs (TIFN-WAA). is presented to aggregate the decision information with TIFNs. Finally, the effectiveness and applicability of the proposed DMADM model, as well as analysis of comparison with another model, are illustrated with an investment example. © 2011 Sharif University of Technology. Production and hosting by Elsevier B.V. All rights reserved.


Hu B.,Yanshan University | Hu B.,State Key Laboratory of Robotics and System HIT
Robotics and Computer-Integrated Manufacturing | Year: 2014

This paper presents a general approach for Jacobian analysis of serial-parallel manipulators (S-PMs) formed by two lower mobility parallel manipulators (PMs) connected in serials. Based on the kinematic relation, coupling and constraint properties of each PM, the unified forward and inverse Jacobian matrices for S-PMs are derived in explicit form. It is shown that the Jacobian matrices of S-PMs have unified forms, which include the complete information of each PM. A (3-RPS)+(3-SPS/UP) S-PM is used as an example to demonstrate the proposed approach. The established model is applicable for S-PMs with various architectures. © 2014 Elsevier Ltd.


Zhang S.-H.,State Key Laboratory of Robotics and System HIT | Zhang S.-H.,Yanshan University | Liu J.-X.,Yanshan University
International Journal of Advanced Robotic Systems | Year: 2012

This paper describes a novel self-occlusion detection approach for depth image using SVM. This work is distinguished by three contributions. The first contribution is the introduction of a new self-occlusion detection idea, which takes the self-occlusion as a classification problem for the first time, thus the accuracy of the detection result is improved. The second contribution is two new self-occlusion-related features, named maximal depth difference and included angle. The third contribution is a specific self-occlusion detection algorithm. Experimental results not only show that the proposed approach is feasible and effective, but also show that our works produce better results than those previously published. © 2012 Zhang and Liu; licensee InTech.


Hu B.,Yanshan University | Hu B.,State Key Laboratory of Robotics and System HIT
Nonlinear Dynamics | Year: 2014

Complete kinematic is an essential and a challenging work for series–parallel manipulators (S–PMs). This paper studied the complete kinematic of a 2(3-SPS+UP) series–parallel manipulator. First, a S–PM formed by two well-known Tricept parallel manipulators (PMs) connected in serial is presented. Second, the forward and inverse displacements are studied using sylvester dialytic elimination method. Third, the forward and inverse Jacobian matrices are established based on integrating the constraint and coupling information of the single PMs into the S–PM. Fourth, simple and compact formulae for the forward and inverse acceleration are derived using vector approach. Finally, the workspace of this S–PM is constructed using CAD variation geometry approach. The results show that the 2(3-SPS+UP) S-PM has multiple forward and inverse position solutions. The existence and uniqueness of the forward, inverse Jacobian matrices and the acceleration formula are shown from their explicit form. The workspace analysis shows that this S–PM has large workspace. The research works provided a theoretical basis for the novel 2(3-SPS+UP) S–PM, as well as a feasible approach for establishing the complete kinematics for S–PMs. © 2014, Springer Science+Business Media Dordrecht.

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