Improvement, Optimization, and Prototyping of a Three Translational Degree of Freedom Parallel Robot

2012 ◽  
Author(s):  
Jonathan Hodgins ◽  
Dan Zhang
Keyword(s):  
Inverse Kinematics ◽  
Optimization Problem ◽  
Parallel Robot ◽  
Degree Of Freedom ◽  
Design Change ◽  
Translational Degree ◽  
Parallel Link

This paper presents an evolutionarily design change for the Delta parallel robot. The proposed design change increases the useful workspace of the robot and aids in permanently avoiding singularities on the workspace. This is accomplished by means of a new intermediate parallel link. This also simultaneously increases the total workspace volume and the stiffness at the outer limits of the workspace. The design is analyzed and the inverse kinematics, stiffness and dexterity relations are formulated. Subsequently, an optimization problem is formulated that aims at taking advantage of the new attributes and illustrate its benefits to the robotic design. The results are clearly illustrated by comparing the robot with the new link to an equivalent robot without it. Lastly, the developed design is 3D modeled to test and verify functionality.

scholarly journals Displacement Analysis of Spherical Mechanisms Having Three or Fewer Loops

2004 ◽  
Vol 126 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Charles W. Wampler
Keyword(s):  
Inverse Kinematics ◽  
Solution Method ◽  
Degree Of Freedom ◽  
Serial Link ◽  
Single Degree Of Freedom ◽  
Displacement Analysis ◽  
Spherical Mechanisms ◽  
Common Center ◽  
Parallel Link ◽  
Spherical Linkages

Spherical linkages, having rotational joints whose axes coincide in a common center point, are sometimes used in multi-degree-of-freedom robot manipulators and in one-degree-of-freedom mechanisms. The forward kinematics of parallel-link robots, the inverse kinematics of serial-link robots and the input/output motion of single-degree-of-freedom mechanisms are all problems in displacement analysis. In this article, loop equations are formulated and solved for the displacement analysis of all spherical mechanisms up to three loops. We show how to solve each mechanism type using either a formulation in terms of rotation matrices or quaternions. In either formulation, the solution method is a modification of Sylvester’s elimination method, leading directly to numerical calculation via standard eigenvalue routines.

A New Design of a 6-DOF Parallel Robot

1990 ◽  
Vol 2 (4) ◽  
pp. 308-315 ◽  
Author(s):  
François Pierrot ◽  
◽  
Masaru Uchiyama ◽  
Pierre Dauchez ◽  
Alain Fournier ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Dynamic Capabilities ◽  
Inverse Dynamics ◽  
Parallel Robot ◽  
Degree Of Freedom ◽  
Mechanical Structure ◽  
Delta Robot ◽  
Good Set ◽  
Six Degree Of Freedom ◽  
Three Degree Of Freedom

This paper presents a six-degree-of-freedom parallel robot which has been recently designed. The design is based on a three-degree-of-freedom parallel robot called DELTA which was designed in Switzerland by EPFL. First, we give equations corresponding to different models of the DELTA robot: forward and inverse kinematics as well as inverse dynamics. An important feature of our method in deriving these models is to use a “good” set of parameters in order to simplify the equations. Then, in an attempt to extend the principle of the DELTA robot mechanical structure to a six-degree-offreedom parallel robot, we propose a new design called HEXA. Equations for kinematics and dynamics of the HEXA robot are presented and show that it has the same dynamic capabilities as the DELTA robot because, like the DELTA robot, it can be built with light-weight materials and easily modeled. Finally, we discuss optimization of the HEXA robot mechanical structure.

Three-Degree-of-Freedom Parallel Robot Arm

2006 ◽  
Author(s):  
Martin Hosek ◽  
Michael Valasek ◽  
Jairo Moura
Keyword(s):  
Parallel Robot ◽  
Degree Of Freedom ◽  
Motion Path ◽  
Angular Orientation ◽  
Robot Arm ◽  
Flat Panel Display ◽  
End Effector ◽  
Cluster Tools ◽  
Manufacturing Applications ◽  
Three Degree Of Freedom

This paper presents single- and dual-end-effector configurations of a planar three-degree of freedom parallel robot arm designed for automated pick-place operations in vacuum cluster tools for semiconductor and flat-panel-display manufacturing applications. The basic single end-effector configuration of the arm consists of a pivoting base platform, two elbow platforms and a wrist platform, which are connected through two symmetric pairs of parallelogram mechanisms. The wrist platform carries an end-effector, the position and angular orientation of which can be controlled independently by three motors located at the base of the robot. The joints and links of the mechanism are arranged in a unique geometric configuration which provides a sufficient range of motion for typical vacuum cluster tools. The geometric properties of the mechanism are further optimized for a given motion path of the robot. In addition to the basic symmetric single end-effector configuration, an asymmetric costeffective version of the mechanism is derived, and two dual-end-effector alternatives for improved throughput performance are described. In contrast to prior attempts to control angular orientation of the end-effector(s) of the conventional arms employed currently in vacuum cluster tools, all of the motors that drive the arm can be located at the stationary base of the robot with no need for joint actuators carried by the arm or complicated belt arrangements running through the arm. As a result, the motors do not contribute to the mass and inertia properties of the moving parts of the arm, no power and signal wires through the arm are necessary, the reliability and maintenance aspects of operation are improved, and the level of undesirable particle generation is reduced. This is particularly beneficial for high-throughput applications in vacuum and particlesensitive environments.

The thermodynamics of intracrystalline sorption I. Models of the sorbed state

1956 ◽  
Vol 234 (1196) ◽  
pp. 24-34 ◽  
Keyword(s):  
Mobile Phase ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Translational Degree ◽  
Sorbate Concentration ◽  
The Ideal

Three basic models of the intracrystalline sorbed state are discussed: a localized phase, a mobile phase possessing two translational degrees of freedom, and a mobile phase with one translational degree of freedom. The isotherm and entropy of each of these models have been investigated for the ideal phase, and where possible the influence of sorbate-sorbate interactions has been considered. Expressions for the molal and differential entropies of each model are given as a function of sorbate concentration. The method of comparing theoretical isotherms and entropies with experimental observations is outlined.

Kinematics of a New High-Precision Three-Degree-of-Freedom Parallel Manipulator

2006 ◽  
Vol 129 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Farhad Tahmasebi
Keyword(s):  
Power Dissipation ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degree Of Freedom ◽  
Base Plane ◽  
Degree Polynomial ◽  
Payload Capacity ◽  
Half Angle ◽  
Three Degree Of Freedom ◽  
Direct Kinematics

Closed-form direct and inverse kinematics of a new three-degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three-DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base mounted, higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of the tangent of the half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.

A Novel Spherical Parallel Manipulator with Circular Guide

2013 ◽  
Vol 325-326 ◽  
pp. 1014-1018
Author(s):  
Hai Rong Fang ◽  
Zhi Hong Chen ◽  
Yue Fa Fang
Keyword(s):  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degree Of Freedom ◽  
High Rigidity ◽  
Geometric Conditions ◽  
Spherical Parallel Manipulator

In this paper, a novel 3-degree-of-freedom (DOF) parallel manipulator that can perform three rotations around the remote centre is presented. The theory of screws and reciprocal screws is employed for the analysis of the geometric conditions. In particular, using circular guide to instead of R joints, so that has the advantage of enabling continuous 360° revolute around Z-axis. The inverse kinematics of mechanism is given and the workspace has a good performance. To compare with the machine constructed with traditional joints, it has the advantage of high rigidity and precision.

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