Stiffness and singularity analysis of foldable parallel mechanism for ship-based stabilized platform

Robotica ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 913-924 ◽  
Author(s):  
Tie-shi Zhao ◽  
Chang Wang ◽  
Xiao Liu ◽  
Hui Bian ◽  
Yan-zhi Zhao
Keyword(s):  
Stiffness Matrix ◽  
Parallel Mechanism ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Influence Coefficient ◽  
Rotational Stiffness ◽  
Closed Chain ◽  
Moving Platform ◽  
Stabilized Platform ◽  
Directional Stiffness

SUMMARYThis paper investigates a 6-degree-of-freedom foldable parallel mechanism for the ship-based stabilized platform, which is driven by closed chain linkages. The velocity and acceleration mappings between the moving platform and inputs of the closed chain linkages are deduced in the form of the first- and second-order influence coefficient matrices. The continuous stiffness matrix is deduced; furthermore, the translation and rotational stiffness along any direction are also deduced. With directional stiffness, the singularity of the mechanism is analyzed, and the explanation of the singularity is given from the viewpoint of stiffness. The directions the platform cannot move or lose its constraints are got from directional stiffness.

Influence Coefficients and Singularity Analysis of a Novel 3-UPU Parallel Mechanism

2017 ◽  
Author(s):  
Ziming Chen ◽  
Dongliang Cheng ◽  
Yang Zhang ◽  
Zhiwei Yang ◽  
Jin Zhou
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Model Simulation ◽  
Hessian Matrix ◽  
Symmetry Plane ◽  
Coefficient Matrix ◽  
Singularity Analysis ◽  
Influence Coefficient ◽  
Parasitic Motion ◽  
Moving Platform

A novel 3-UPU parallel mechanism with two rotational and one translational (2R1T) degrees of freedom (DOFs) is analyzed in this paper. The base and moving platform of this mechanism are always symmetric about a middle symmetry plane. The moving platform can rotate continuously about any axis on the middle symmetry plane, so there exists no parasitic motion during the rotation. Using the kinematic influence coefficient theory and the imaginary mechanism method, the first and second order influence coefficient matrix (namely Jacobian matrix and Hessian matrix) of this mechanism are derived. The relations between the velocity and acceleration of the moving platform and the actuated links are obtained. In order to verify the correctness of the theory, two numerical examples are enumerated and varified by the 3D model simulation. The singularities of this mechanism is discussed and the singular configurations of the mechanism, including one kind of limb singularity and two kinds of platform singularities, are obtained.

KINEMATICS AND WORKSPACE ANALYSIS OF A 3 DEGREE OF FREEDOM PARALLEL MECHANISM WITH PARALLELOGRAM LINKAGE

2017 ◽  
Vol 41 (5) ◽  
pp. 922-935
Author(s):  
HongJun San ◽  
JunSong Lei ◽  
JiuPeng Chen ◽  
ZhengMing Xiao ◽  
JunJie Zhao
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Analytical Method ◽  
Theoretical Basis ◽  
Parallel Mechanism ◽  
Graphical Method ◽  
Degree Of Freedom ◽  
Workspace Analysis ◽  
Fixed Base ◽  
Moving Platform

In this paper, a 3-DOF translational parallel mechanism with parallelogram linkage was studied. According to the space vector relation between the moving platform and the fixed base, the direct and inverse position solutions of this mechanism was deduced through analytical method. In addition, the error of the algorithm was analyzed, and the algorithm had turned out to be effective and to have the satisfactory computational precision. On the above basis, the workspace of this mechanism was found through graphical method, which was compared with that of finding through Monte Carlo method, and there was the feasibility for analyzing the workspace of the mechanism by graphical method. The characteristic of the mechanism was analyzed by comparing the results of two analysis methods, which provided a theoretical basis for the application of the mechanism.

Dynamics of a Two-DOF Parallel Pointing Mechanism

2005 ◽  
Author(s):  
Alessandro Cammarata ◽  
Rosario Sinatra
Keyword(s):  
Numerical Simulation ◽  
Parallel Mechanism ◽  
Inverse Dynamics ◽  
Kinematic Model ◽  
Degree Of Freedom ◽  
Numerical Examples ◽  
Proposed Model ◽  
Dynamic Analyses ◽  
Moving Platform ◽  
Two Degree Of Freedom

This paper presents kinematic and dynamic analyses of a two-degree-of-freedom pointing parallel mechanism. The mechanism consists of a moving platform, connected to a fixed platform by two legs of type PUS (prismatic-universal-spherical). At first a simplified kinematic model of the pointing mechanism is introduced. Based on this proposed model, the dynamics equations of the system using the Natural Orthogonal Complement method are developed. Numerical examples of the inverse dynamics results are presented by numerical simulation.

Research on the Configurations and Singularity of Serial-Parallel Mechanism

2011 ◽  
Vol 393-395 ◽  
pp. 265-268
Author(s):  
Jian Guo Luo ◽  
Mao Yan He
Keyword(s):  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Synthesis Method ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Spatial Mobility

Methods to analysis the DOF(degree of freedom) and singularity of pure serial and pure parallel manipulator, which can not be used to the serial-parallel manipulator directly, three type of practical topological units and one type of virtual topological unit adopted, Synthesis method of topological dimensionality of the spatial mobility of each topological unit integrated together, architectures of serial-paralle mechanism discussed, also the formula and process of its topological dimensionality of spatial mobility presented, singularity analysis of serial-parallel mechanism can be carried out based on the forgoing results.

Design and Analysis of 3-DOF Micromanipulator Driven by Piezoelectric Actuators

2008 ◽  
Author(s):  
Shihua Li ◽  
Yue Zhang ◽  
Zhen Huang ◽  
Changcheng Yu ◽  
Wenhua Ding
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Parallel Mechanism ◽  
Piezoelectric Actuators ◽  
Coefficient Matrix ◽  
Influence Coefficient ◽  
Velocity Analysis ◽  
First Order ◽  
Flexure Hinges ◽  
Moving Platform

A novel 3-DOF parallel micromanipulator which is driven by piezoelectric actuators has been developed that based on 3–5R parallel mechanism. The micromanipulator consists of a moving platform, a fixed platform, three 5R fixed-length chains and three piezoelectric actuators. In this paper, the first-order influence coefficient matrix of the micromanipulator is given, and then the velocity analysis is given. The dimension of the platform and flexure hinges and the position of flexure are designed, and the safety check of the flexible hinges and the designed mechanism is done with the aid of finite element modeling to provide good stiffness with little bending deformation of the platform. The merits of parallel mechanism and piezoelectric actuators are reflected in this mechanism.

scholarly journals A New Metamorphic Parallel Leg Mechanism with Reconfigurable Moving Platform

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yong Xu ◽  
Zheng Liang ◽  
Jiali Liu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Screw Theory ◽  
Degree Of Freedom ◽  
Walking Robots ◽  
Metamorphic Mechanism ◽  
Parallel Leg Mechanism ◽  
Moving Platform ◽  
Configuration Synthesis

This paper proposes the concept of full configuration state of metamorphic mechanism. Based on the concept, the configuration synthesis principle of metamorphic parallel mechanism is put forward. Firstly, a metamorphic parallel mechanism in full configuration state is synthesized, and then full configuration state evolves into a specific configuration state by increasing constraints or decreasing degrees of freedom. A reconfigurable moving platform based on the triple symmetric Bricard spatial closed-loop mechanism with a single degree of freedom is proposed. Based on this, a new method for switching motion configuration states of the metamorphic parallel mechanism is constructed. According to the configuration synthesis principle presented above, a novel metamorphic parallel mechanism that can switch between three- and four-degree-of-freedom is synthesized, and then the triple symmetric Bricard spatial closed-loop mechanism is used as the reconfigurable moving platform (that is, the reconfigurable foot of a walking robot) of the metamorphic mechanism, and thus, a novel metamorphic parallel leg mechanism is created. The screw theory is used to verify the degrees of freedom of the new type of metamorphic parallel leg. The proposed metamorphic parallel leg mechanism is expected to improve flexibility and adaptability of walking robots in unstructured environment.

Kinematic Analysis of 4-UPU Parallel Mechanism Based on Influence Coefficient

2015 ◽  
Vol 741 ◽  
pp. 691-696 ◽  
Author(s):  
Guang Lan Xia ◽  
Xing Wei Hu ◽  
Bao Lin Yin ◽  
Feng Yu
Keyword(s):  
Numerical Analysis ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Coefficient Matrix ◽  
Degree Of Freedom ◽  
Kinematics And Dynamics ◽  
Influence Coefficient ◽  
Mechanism Analysis ◽  
Acceleration Coefficient ◽  
Mechanism Kinematic

Mechanism kinematic influence coefficient deeply reflects the essence of the kinematics and dynamics mechanism, analysis of the problems of many institutions can use the influence coefficient of clear and clearly expressed. In this paper, with less degree of freedom parallel mechanism as the research object, through the virtual mechanism method to derive one or two order influence coefficient matrix, based on the analysis of the mechanism and influence of speed and acceleration coefficient matrix. Finally, the precision of the method for solving the kinematics is proved by examples of numerical analysis.

Kinematic Analysis of A Novel 2-UPU/2-URU Parallel Mechanism

2011 ◽  
Vol 317-319 ◽  
pp. 469-474
Author(s):  
Shi Hua Li ◽  
Zhi Song Wang ◽  
Chang Cheng Yu ◽  
Wen Gong
Keyword(s):  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Degree Of Freedom ◽  
Influence Coefficient ◽  
Performance Curve ◽  
Kinematics Analysis

Abstract. In this paper, a novel type of 2-UPU/2-URU asymmetric parallel mechanism is put forward, the degree of freedom and kinematics characteristics of the mechanism is analyzed. Firstly, based on screw theory, the degree of freedom of the mechanism is analyzed by using modified Grübler-Kutzbach formula of Degree of Freedom, the method is ingenious and simple. Then the kinematics analysis is done. Finally, the velocity and acceleration of the mechanism is analyzed by combining kinematic influence coefficient theory with imaginary mechanism method, and draw the velocity and acceleration performance curve of the mechanism with the MATLAB. This paper lays the foundation for further research of the parallel mechanism.

Singularity Analysis of a New 2-DOF Parallel Tilter

2012 ◽  
Vol 224 ◽  
pp. 504-509
Author(s):  
Hai Dong Wang ◽  
Jing Sun ◽  
Yu Quan Bi ◽  
Mao Sheng Yang
Keyword(s):  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Coordinate Transformations ◽  
Analytic Equation ◽  
Singular Configuration ◽  
Two Degree Of Freedom

One type of spatial new parallel mechanism with two degree of freedom is proposed.. The position and velocity analytic equation are constructed based on the coordinate transformations. Finally, the singular configuration of the tilter is analyzed by the forward and the inverse Jacobian matrix.

Kinematics Simulation of Parallel Mechanism Based on ADAMS

2012 ◽  
Vol 538-541 ◽  
pp. 479-482
Author(s):  
Xin Yu Du ◽  
Hong Wei Liu
Keyword(s):  
Parallel Mechanism ◽  
Screw Theory ◽  
Virtual Prototype ◽  
Degree Of Freedom ◽  
Kinematics Analysis ◽  
Kinematics Simulation ◽  
Spatial Parallel Mechanism ◽  
Moving Platform ◽  
Simulation Results ◽  
Position And Orientation

In this paper,a kind of 3-UPU spatial parallel mechanism is introduced. Through deep analysis of the degree-of-freedom (DoF) for the platform using screw theory， the position and orientation of the moving platform is discussed. At last, the 3D virtual prototype modeling of this 3-UPU parallel mechanism based on software ADAMS is developed; the kinematics simulation and analysis are also carried out accordingly. From the simulation results, we can see that the proposed calculation of the DoFs and kinematics analysis is correct.

Sign in / Sign up

Export Citation Format

Share Document