scholarly journals Performance Analysis of Gough Stewart Platform with 6 Limbs

2020 ◽  
Vol 22 (1) ◽  
pp. 133-142
Author(s):  
A. Chandrashekhar ◽  
G. Satish Babu
Keyword(s):  
Optimal Design ◽  
Performance Analysis ◽  
Parallel Manipulator ◽  
Jacobian Matrix ◽  
Stewart Platform ◽  
Stiffness Index ◽  
Important Criterion ◽  
Transmission Index ◽  
Application Fields ◽  
Optimal Designing

AbstractThis paper concentrates on widespread study of parallel manipulator. It focuses on optimal designing of manipulator which has a large number of application fields. Optimal design is an important criterion to improve the accuracy of a robot. Through optimal design a robot can achieve isotropic configurations where the condition number of its jacobian matrix equals one. In this we are also concentrating on transmission index and stiffness index along with their plots, which can affect the kinetostatic performance of the robot. In this the singularity of Gough Stewart platform is also studied.

Performance Analysis and Optimal Design of a 3-DOF 3-PRUR Parallel Mechanism

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Daxing Zeng ◽  
Zhen Huang ◽  
Wenjuan Lu
Keyword(s):  
Optimal Design ◽  
Performance Analysis ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Performance Indices ◽  
Geometrical Characteristics

In this paper, a 3-DOF 3-PRUR parallel mechanism (PM) is chosen for performance analysis and optimal design. First, the mobility of the PM is analyzed by using screw theory. Then, the kinematics of this PM is studied based on the geometrical characteristics and the Jacobian matrix is derived. Furthermore, we research some performance indices with respect to the Jacobian matrix over the whole workspace and nondimensional parameters when the input is given, and their performance atlases are obtained with different inputs. Finally, the optimal design of the PM is determined according to the performance atlases, and some examples are presented.

Formulating an Invariant Manipulability Index of Gough-Stewart Platform

2012 ◽  
Vol 479-481 ◽  
pp. 2321-2326
Author(s):  
Guo Jun Liu ◽  
Shu Tao Zheng ◽  
Xiao Chu Liu ◽  
Ying Bo Wang ◽  
Jun Wei Han
Keyword(s):  
Optimal Design ◽  
Physical Meaning ◽  
Jacobian Matrix ◽  
Extreme Values ◽  
Random Search ◽  
Stewart Platform ◽  
Flight Simulators ◽  
Motion Simulator ◽  
Commercial Flight ◽  
End Effectors

Manipulability indexes have been extensively used as objective functions or constraints in the optimal design of robots, especially for the robots with pure active joints and the end-effectors only involving positioning or orientation. The moving platform of Gough-Stewart platform can involve both positioning and orientation, which leads to the conventional Jacobian matrix with entries bearing disparate physical units, then the established manipulability index based on the conventional Jacobian matrix has no physical meaning and is variable under a change of units. Based on a dimensionless Jacobian matrix, this paper established a new manipulability index, which has physical meaning and is invariant under a change of units. In order to design a good performance motion simulator, the extreme values of the new and old manipulability indexes of 2 commercial flight simulators in their reachable workspaces were found by random search method, respectively. From the results, the extreme values of the new manipulability index are in regularity, and can be used as references in the optimal design of the Gough-Stewart platform as motion simulator.

DESIGN FOR OPTIMAL PERFORMANCE OF 3-RPS PARALLEL MANIPULATOR USING EVOLUTIONARY ALGORITHMS

2013 ◽  
Vol 37 (2) ◽  
pp. 135-160 ◽  
Author(s):  
Sabbavarapu Ramana Babu ◽  
Vegesina Ramachandra Raju ◽  
Koona Ramji
Keyword(s):  
Parallel Manipulator ◽  
Pareto Front ◽  
General Type ◽  
Jacobian Matrix ◽  
Search Method ◽  
Stiffness Index ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Working Capacity ◽  
Multi Objective

This paper presents an optimal kinematic design for a general type of 3-RPS spatial parallel manipulator based on multi-objective optimization. The objective functions considered are Global Conditioning Index (GCI), Global stiffness Index (GSI) and Workspace volume. The objective functions are optimized simultaneously to improve the dexterity as well as the workspace volume which represents the working capacity of a parallel manipulator. A multi-objective Evolutionary Algorithm based on the control elitist non-dominated sorting genetic algorithm is adopted to find the true optimal Pareto front. A constraint Jacobian matrix is derived analytically and the manipulator workspace is generated by numerical search method. The static analysis of the manipulator is also carried out to determine the compliance of the end-effecter.

scholarly journals Design and performance analysis of a 3-RRR spherical parallel manipulator for hip exoskeleton applications

2017 ◽  
Vol 4 ◽  
pp. 205566831769759 ◽  
Author(s):  
Soheil Sadeqi ◽  
Shaun P Bourgeois ◽  
Edward J Park ◽  
Siamak Arzanpour
Keyword(s):  
Experimental Study ◽  
Performance Analysis ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Jacobian Matrix ◽  
Kinematics Analysis ◽  
Normal Gait ◽  
Sensitivity Indices ◽  
And Performance ◽  
Spherical Parallel Manipulator

This paper presents the design and performance analysis and experimental study of a 3-RRR spherical parallel manipulator in the context of hip exoskeleton applications. First, the mechanism’s inverse kinematics analysis and Jacobian matrix development are revisited. Manipulability, dexterity, and rotational sensitivity indices are then evaluated for two different methods of attachment to the human body. The superior attachment method in terms of these performance measures is indicated, and an experimental study based on the selected method is conducted; the experiment involves testing the capability of a 3-RRR manipulator’s end-effector in tracking the motions experienced by a human hip joint during normal gait cycles. Finally, the results of the experimental study indicate that the manipulator represents a feasible hip exoskeleton solution providing total kinematic compliance with the human hip joint’s 3-degree-of-freedom motion capabilities.

Dimensionally Homogeneous Jacobian and Condition Number

2016 ◽  
Vol 836 ◽  
pp. 42-47 ◽  
Author(s):  
Latifah Nurahmi ◽  
Stéphane Caro
Keyword(s):  
Performance Analysis ◽  
Condition Number ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Parallel Manipulators ◽  
Moving Platform ◽  
Conditioning Number

This paper deals with the formulation of the dimensionally homogeneous extended Jacobian matrix, which is an important issue for the performance analysis of f degrees-of-freedom (f ≤6) parallel manipulators having coupled rotational and translational motions. By using the f independent coordinates to define the permitted motions and (6-f) independent coordinates to define the restricted motions of the moving platform, the 6×6 dimensionally homogeneous extended Jacobian matrix is derived for non-redundant parallel manipulators. The conditioning number of the parallel manipulators is computed to evaluate the homogeneous extended Jacobian matrix, the homogeneous actuation wrench matrix, and the homogeneous constraint wrench matrix to evaluate the performance of the parallel manipulators. By using these indices, the closeness of a pose to different singularities can be detected. An illustrative example with the 3-RPS parallel manipulator is provided to highlight the effectiveness of the approach and the proposed indices.

scholarly journals Performance Analysis and Optimization of a 6-DOF Robotic Crusher

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Guoguang Li ◽  
Boqiang Shi ◽  
Ruiyue Liu ◽  
Jie Gu
Keyword(s):  
Performance Analysis ◽  
Condition Number ◽  
Mechanical Performance ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Practical Application ◽  
Transmission Performance ◽  
Instantaneous Power ◽  
Transmission Index ◽  
Optimization Function

Considering the complexity of multidimension parameters and the mechanical performance of a 6-DOF robotic crusher, a multiobjective optimization function based on the transmission index and condition number is established. As an important operation in the screw theory, the reciprocal product between the transmission wrench screw of an actuator and the output twist screw of the mantle assembly is used to represent the instantaneous power. The expression of transmission index is derived according to the principle that constraint wrench screws apply no work to the mantle assembly. It can be used as a criterion to evaluate the transmission performance. Then, based on the Jacobian matrix, the equation of condition number is constructed which provides a criterion for evaluating kinematic accuracy. Finally, the workspace and singularity of the 6-DOF robotic crusher are analyzed to verify the rationality of the optimized variables. The results show that the optimized structure can completely crush the material in the workspace and effectively avoid singularity, which provides a basis for practical application.

Optimal design of a redundant spherical parallel manipulator

Robotica ◽  
1997 ◽  
Vol 15 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Sylvie Leguay-Durand ◽  
Claude Reboulet
Keyword(s):  
Optimal Design ◽  
Kinematic Analysis ◽  
Parallel Manipulator ◽  
Structure Optimization ◽  
Kinematic Design ◽  
Spherical Wrist ◽  
Redundant Structure ◽  
Spherical Parallel Manipulator

A new kinematic design of a parallel spherical wrist with actuator redundancy is presented. A special feature of this parallel manipulator is the arrangement of co-axial actuators which allows unlimited rotation about any axis inside a cone-shaped workspace. A detailed kinematic analysis has shown that actuator redundancy not only removes singularities but also increases workspace while improving dexterity. The structure optimization has been performed with a global dexterity criterion. Using a conditioning measure, a comparison with a non-redundant structure of the same type was performed and shows that a significant improvement in dexterity has been obtained.

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