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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. Source


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. Source


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. Source


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. Source


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. Source

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