Kinematic analysis of parallel mechanisms at singular points where a connecting chain has local mobility

2006 ◽  
Vol 41 (8) ◽  
pp. 945-957 ◽  
Author(s):  
Yukio Takeda
Keyword(s):  
Kinematic Analysis ◽  
Singular Points ◽  
Parallel Mechanisms ◽  
Local Mobility

A Simple Method for Inverse Kinematic Analysis of the General 6R Serial Robot

2006 ◽  
Author(s):  
Zhi Xin Shi ◽  
Yu Feng Luo ◽  
Lu Bing Hang ◽  
Ting Li Yang
Keyword(s):  
Kinematic Analysis ◽  
Inverse Kinematics ◽  
Algebraic Method ◽  
Inverse Kinematic ◽  
New Method ◽  
One Dimension ◽  
Parallel Mechanisms ◽  
Simple Method ◽  
Inverse Kinematics Problem ◽  
Serial Robot

Because the solution to inverse kinematics problem of the general 5R serial robot is unique and its assembly condition has been derived, a simple effective method for inverse kinematics problem of general 6R serial robot or forward kinematics problem of general 7R single-loop mechanism is presented based on one-dimension searching algorithm. The new method has the following features: (1) Using one-dimension searching algorithm, all the real inverse kinematic solutions are obtained and it has higher computing efficiency; (2) Compared with algebraic method, it has evidently reduced the difficulty of deducing formulas. The principle of the new method can be generalized to kinematic analysis of parallel mechanisms.

Forward/Reverse Velocity and Acceleration Analysis for a Class of Lower-Mobility Parallel Mechanisms

2006 ◽  
Vol 129 (4) ◽  
pp. 390-396 ◽  
Author(s):  
Si J. Zhu ◽  
Zhen Huang ◽  
Hua F. Ding
Keyword(s):  
Kinematic Analysis ◽  
Jacobian Matrix ◽  
Hessian Matrix ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Analysis Method ◽  
Rear Part ◽  
Lower Mobility ◽  
Acceleration Analysis

This paper proposes a novel kinematic analysis method for a class of lower-mobility mechanisms whose degree-of-freedom (DoF) equal the number of single-DoF kinematic pairs in each kinematic limb if all multi-DoF kinematic pairs are substituted by the single one. For such an N-DoF (N<6) mechanism, this method can build a square (N×N) Jacobian matrix and cubic (N×N×N) Hessian matrix. The formulas in this method for different parallel mechanisms have unified forms and consequently the method is convenient for programming. The more complicated the mechanism is (for instance, the mechanism has more kinematic limbs or pairs), the more effective the method is. In the rear part of the paper, mechanisms 5-DoF 3-R(CRR) and 5-DoF 3-(RRR)(RR) are analyzed as examples.

Kinematic analysis of deployable parallel mechanisms

2019 ◽  
Vol 234 (1) ◽  
pp. 263-272 ◽  
Author(s):  
Shuofei Yang ◽  
Yangmin Li
Keyword(s):  
Kinematic Analysis ◽  
Theoretical Foundation ◽  
Parallel Mechanisms ◽  
Solar Panels ◽  
Kinematic Modeling ◽  
Modeling And Analysis ◽  
Velocity Modeling ◽  
Parallel Structures ◽  
Simulation And Experiment ◽  
Instantaneous Screw

Inspired by the existing closed-loop deployable mechanisms and parallel mechanisms, a new kind of mechanisms, named deployable parallel mechanisms, is introduced in this paper, and the kinematic analysis is presented. As the combination of deployable mechanisms and parallel mechanisms, deployable parallel mechanisms have advantages of both the two kinds of mechanisms. They can be easily constructed by origami and folded from spatial structures into paper slices. Due to the parallel structures, they can be designed to have higher stiffness and larger volume compressibility than the existing deployable mechanisms. Thus, deployable parallel mechanisms have tremendous potential to be applied in the design of spatial solar panels, elastic reconfigurable robotic modules, etc. With reference to the kinematic analysis of parallel mechanisms, a finite and instantaneous screw method for kinematics of deployable parallel mechanisms is proposed, which is a generic method that is suitable for displacement and velocity modeling and analysis of any deployable parallel mechanism. A typical mechanism with symmetrical structure is taken as an example to show the validity of the proposed method, and simulation and experiment are carried out to verify the obtained results of kinematics. This paper puts forth the basic concepts of deployable parallel mechanisms and lays a theoretical foundation for their kinematic modeling and analysis.

Workspace Analysis of Parallel Manipulator for Telemicromanipulation Systems

2001 ◽  
Vol 13 (5) ◽  
pp. 488-496 ◽  
Author(s):  
Noriaki Ando ◽  
◽  
Masahiro Ohta ◽  
Kohei Gonda ◽  
Hideki Hashimoto
Keyword(s):  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Parallel Mechanisms ◽  
Dual Systems ◽  
Position Accuracy ◽  
Control Scheme ◽  
Workspace Analysis ◽  
Manipulator Control ◽  
Vr Simulator

This paper describes the research results on telemicromanipulation systems for microlevel tasks. Because of its better manipulation precision, stiffness and speed characteristics, the parallel mechanism micromanipulator was chosen to compose our systems. First, the kinematic analysis of our original manipulator mechanism is performed. Then, the structure of our parallel manipulator, control scheme, and experimental results are shown. Position accuracy and device control characteristics are analyzed and the feasibility of the use of parallel mechanisms for micromanipulator is then discussed. A parallel manipulator motion is restricted by 3 factors: mechanical limits of the passive joints, collision between links and actuators limitations. Results of the numerical workspace analysis considering the above factors are shown. We are proposing the use of dual manipulators for implementing improved real manipulation systems. The first kinematics and workspace analysis of dual systems using the VR simulator are also shown.

Mobility Change in Two Types of Metamorphic Parallel Mechanisms

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
Dongming Gan ◽  
Jian S. Dai ◽  
Qizheng Liao
Keyword(s):  
Parallel Mechanism ◽  
Type A ◽  
Parallel Mechanisms ◽  
Mobility Analysis ◽  
Topological Change ◽  
Mobility Factor ◽  
Local Mobility

This paper presents a new joint coined as the rT joint and proposes two types of metamorphic parallel mechanisms assembled with this rT joint. In the first type, the mechanism changes its topology by turning the rT joints in all limbs into different configurations. This change in mobility is completed by two cases illustrated by a 3(rT)PS metamorphic parallel mechanism having variable mobility from 3 to 6 and a 3(rT)P(rT) parallel mechanism having various configurations including pure translations, pure rotations, and mobility 4. In the second type, a central strut with the rT joint is added in a parallel mechanism. The variable mobility of the mechanism results from the topological change of the central (rT)P(rT) strut. This is illustrated in a 3SPS-1(rT)P(rT) metamorphic parallel mechanism, which changes its mobility from 4 to 5. It is demonstrated in mobility analysis that the change in local mobility of each limb results in the change in the platform mobility that a metamorphic process can be achieved. This particular analysis leads to advancement of improved Grübler–Kutzbach criterion by introducing the local mobility factor in the mobility analysis.

Kinematic Analysis and Stiffness Characteristics of a Hybrid 2-DOF 7-Bar Linkage

2004 ◽  
Author(s):  
Zhenjun Luo ◽  
Jian S. Dai
Keyword(s):  
Kinematic Analysis ◽  
Stiffness Index ◽  
Structural Stiffness ◽  
Parallel Mechanisms ◽  
Range Of Movement ◽  
Comparative Analyses ◽  
Hybrid Mechanisms ◽  
High Dynamic ◽  
Stiffness Characteristics ◽  
Kinematic Properties

Parallel mechanisms have drawn interest due to many advantages such as large payload ratio, high structural stiffness, low inertias and high dynamic capacities. But there are also drawbacks such as limited workspace and more singularities. Therefore many research efforts have been given to hybrid mechanisms, especially to hybrid serial-parallel mechanisms. This paper presents a new hybrid 2-DoF 7-bar linkage and several related linkages. Such mechanisms allow much larger range of movement than parallel mechanisms, yet have larger stiffness than serial mechanisms, and are desirable for robot fingers and limbs. Kinematic properties of the hybrid 2-DoF 7-bar planar linkage are analyzed. Comparative analyses between it and several 2-DoF linkages are given based on conditioning mapping, stiffness mapping, global conditioning index and global stiffness index. The results demonstrate the applicability of such linkages.

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