On the design of gravity-compensated six-degree-of-freedom parallel mechanisms

2002 ◽  
Author(s):  
C.M. Gosselin ◽  
Jiegao Wang
Keyword(s):  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Six Degree Of Freedom

WRENCH-CLOSURE WORKSPACE OF SIX-DOF PARALLEL MECHANISMS DRIVEN BY 7 CABLES

2005 ◽  
Vol 29 (4) ◽  
pp. 541-552 ◽  
Author(s):  
Marc Gouttefarde ◽  
Clément M. Gosselin
Keyword(s):  
Cross Sections ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Six Dof ◽  
Moving Platform ◽  
Six Degree Of Freedom

The wrench-closure workspace (WCW) of six-degree-of-freedom (DOF) parallel cable-driven mechanisms is defined as the set of poses of the moving platform of the mechanism for which any external wrench can be balanced by tension forces in the cables. This workspace is fundamental in order to analyze and design parallel cable-driven mechanisms. This paper deals with the class of six-DOF mechanisms driven by seven cables. Two theorems, which provide efficient means to test whether a given pose of the moving platform belongs to the WCW, are proposed. One of these two theorems reveals the nature of the boundary of the constant-orientation cross sections of the WCW. Moreover, some of the possible applications of these theorems are discussed and illustrated.

Design of Statically Balanced Six-Degree-of-Freedom Parallel Mechanisms Based on Tensegrity System

2009 ◽  
Author(s):  
S. M. Mehdi Shekarforoush ◽  
Mohammad Eghtesad ◽  
Mehrdad Farid
Keyword(s):  
Parallel Mechanism ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Engineering Systems ◽  
Suitable Alternative ◽  
Tensegrity Systems ◽  
Six Degree Of Freedom

A parallel mechanism that is based on tensegrity system is studied in this article. Tensegrity systems are a suitable alternative for conventional engineering systems like mechanisms for some application. In this article, tensegrity mechanisms are classified into tensegrity mechanism with passive and active compliant components. Based on this classification, two types of six-degree-of-freedom parallel mechanism are proposed and kinematics and static of them are solved. The first type is the 6–6 tensegrity mechanism with passive compliant components and the second type is the 6-3 tensegrity mechanism with active compliant components.

scholarly journals A Six Degree-of-Freedom Haptic Device Based on the Orthoglide and a Hybrid Agile Eye

2006 ◽  
Author(s):  
Damien Chablat ◽  
Philippe Wenger
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Haptic Device ◽  
Parallel Mechanisms ◽  
Real Time Control ◽  
Time Control ◽  
Rotational Motions ◽  
Six Degree Of Freedom ◽  
Rotary Motor ◽  
Three Degrees Of Freedom

This paper is devoted to the kinematic design of a new six degree-of-freedom haptic device using two parallel mechanisms. The first one, called orthoglide, provides the translation motions and the second one, called agile eye, produces the rotational motions. These two motions are decoupled to simplify the direct and inverse kinematics, as it is needed for real-time control. To reduce the inertial load, the motors are fixed on the base and a transmission with two universal joints is used to transmit the rotational motions from the base to the end-effector. Two alternative wrists are proposed (i), the agile eye with three degrees of freedom or (ii) a hybrid wrist made by the assembly of a two-dof agile eye with a rotary motor. The last one is optimized to increase its stiffness and to decrease the number of moving parts.

Static Balancing of Spatial Six-Degree-of-Freedom Parallel Mechanisms With Revolute Actuators

1998 ◽  
Author(s):  
Jiegao Wang ◽  
Clément M. Gosselin
Keyword(s):  
Potential Energy ◽  
Center Of Mass ◽  
Total Potential Energy ◽  
Degree Of Freedom ◽  
Gravitational Potential Energy ◽  
Parallel Mechanisms ◽  
Static Balancing ◽  
Total Potential ◽  
Global Center ◽  
Six Degree Of Freedom

Abstract The static balancing of spatial six-degree-of-freedom parallel mechanisms or manipulators with revolute actuators is studied in this paper. Two static balancing methods, namely, using counterweights and using springs, are used. The first method leads to mechanisms with a stationary global center of mass while the second approach leads to mechanisms whose total potential energy (including the elastic potential energy stored in the springs as well as the gravitational potential energy) is constant. The position vector of the global center of mass and the total potential energy of the manipulator are first expressed as functions of the position and orientation of the platform. Then, conditions for static balancing are derived from the resulting expressions. Finally, examples are given in order to illustrate the design methodologies.

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