Determination of the Link Lengths for a Spatial 3-DOF Parallel Manipulator

2005 ◽  
Vol 128 (2) ◽  
pp. 365-373 ◽  
Author(s):  
Xin-Jun Liu ◽  
Jinsong Wang ◽  
Jongwon Kim
Keyword(s):  
Optimum Design ◽  
Parallel Manipulator ◽  
Design Space ◽  
Graphical Representation ◽  
Geometric Parameters ◽  
Performance Criteria ◽  
Design Parameters ◽  
Design Result ◽  
Basic Similarity

This paper addresses the issue of determining the optimal geometric parameters of a 3-DOF parallel manipulator. One of the advantages of the manipulator is that the moving platform exhibits high tilting capabilities, e.g., as much as ±50deg. The first step of the new optimal methodology proposed in this paper to achieve the optimum design involves developing a design space that includes all possible basic similarity manipulators. The next step deals with the graphical representation of atlases that can illustrate relationships between performance criteria and design parameters. With such atlases, the designer can identify an optimum region with respect to the specification on performances. The region contains the optimum candidates, from which we can select one directly. Finally, the geometric parameters of the manipulator can be reached by comparing the desired workspace and the good-conditioning workspace. The design methodology discussed in this paper has no process to establish the objective function and does not involve any optimization algorithm, which is normally used in traditional optimization. We expect that since each manipulator in the developed design space represents all of its similarity manipulators in terms of performances, this method will guarantee an optimum design result.

Optimal kinematic design of a three translational DoFs parallel manipulator

Robotica ◽  
2005 ◽  
Vol 24 (2) ◽  
pp. 239-250 ◽  
Author(s):  
Xin-Jun Liu
Keyword(s):  
Parallel Manipulator ◽  
Design Space ◽  
Design Method ◽  
Performance Criteria ◽  
Stiffness Index ◽  
Design Parameters ◽  
Kinematic Design ◽  
Normalized Parameters ◽  
The Relationship ◽  
Design Result

In this paper, an optimal kinematic design method of a three translational DoFs parallel manipulator is presented. The design is based on the concept of performance chart, which can show the relationship between a criterion and design parameters graphically and globally. The normalization on the design parameters of the studied manipulator makes it possible that the design space, which is made up of the normalized parameters, is limited. The design space includes of all possible basic similarity manipulators (BSMs). As any one of the BSMs represents all of its similarity manipulators (SMs) in terms of performances, if one BSM is optimal, its SMs are optimized as well. The said optimal BSM is from the optimum region, which is the intersecting result of involved performance charts. In this paper, the related performance criteria are good-conditioning workspace (GCW), global conditioning index (GCI) and global stiffness index (GSI). As an applying example, a design result of the parallel manipulator with a desired task workspace is presented. The results of the paper are very useful for the design and application of a parallel manipulator.

Determination of the Workspace of a Three-Degrees-of-Freedom Parallel Manipulator Using a Three-Dimensional Computer-Aided-Design Software Package and the Concept of Virtual Chains1

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Andrew Johnson ◽  
Xianwen Kong ◽  
James Ritchie
Keyword(s):  
Computer Aided Design ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Graphical Representation ◽  
Three Dimensional ◽  
Parallel Manipulators ◽  
Workspace Analysis ◽  
Computer Aided ◽  
Aided Design

The determination of workspace is an essential step in the development of parallel manipulators. By extending the virtual-chain (VC) approach to the type synthesis of parallel manipulators, this technical brief proposes a VC approach to the workspace analysis of parallel manipulators. This method is first outlined before being illustrated by the production of a three-dimensional (3D) computer-aided-design (CAD) model of a 3-RPS parallel manipulator and evaluating it for the workspace of the manipulator. Here, R, P and S denote revolute, prismatic and spherical joints respectively. The VC represents the motion capability of moving platform of a manipulator and is shown to be very useful in the production of a graphical representation of the workspace. Using this approach, the link interferences and certain transmission indices can be easily taken into consideration in determining the workspace of a parallel manipulator.

Determination of the Workspace of 6-DOF Parallel Manipulators

1989 ◽  
Author(s):  
C. Gosselin
Keyword(s):  
Parallel Manipulator ◽  
Graphical Representation ◽  
Three Dimensional ◽  
Parallel Manipulators ◽  
Degree Of Freedom ◽  
Geometrical Properties ◽  
Cartesian Space ◽  
Six Degree Of Freedom

Abstract This paper presents an algorithm for the determination of the workspace of parallel manipulators. The method described here, which is based on geometrical properties of the workspace, leads to a simple graphical representation of the regions of the three-dimensional Cartesian space that are attainable by the manipulator with a given orientation of the platform. Moreover, the volume of the workspace can be easily computed by performing an integration on its boundary, which is obtained from the algorithm. Examples are included to illustrate the application of the method to a six-degree-of-freedom fully-parallel manipulator.

Characteristics of a Self-Lubricated Stepped Thrust Pad of Infinite Width With Compressible Lubricant

1959 ◽  
Vol 81 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Kikuo C. Kochi
Keyword(s):  
Optimum Design ◽  
Practical Interest ◽  
Numerical Data ◽  
Numerical Results ◽  
Design Parameters ◽  
Analytic Expressions ◽  
Thrust Pad ◽  
Compressible Lubricant

Harrison’s equation for the pressure in a gas-lubricated bearing of infinite width is solved for a thrust pad with stepped configuration. Analytic expressions for the pressure and load are developed. Numerical results are presented graphically. The analytic expressions together with the numerical data permit most of those characteristics of the stepped pad of practical interest to be completely determinable. Determination of optimum design parameters is given by a pair of graphs.

Workspace atlases for the computer aided design of the Delta robot

2003 ◽  
Vol 217 (8) ◽  
pp. 861-869 ◽  
Author(s):  
X-J Liu ◽  
J Wang ◽  
H Zheng
Keyword(s):  
Physical Model ◽  
Optimum Design ◽  
Computer Aided Design ◽  
Solution Space ◽  
Parallel Robots ◽  
New Method ◽  
Performance Criteria ◽  
Computer Aided ◽  
Aided Design

Parallel robots lead to complex kinematics equations, so determination of their workspaces is a challenging issue. The workspace of a robot is not fully characterized by its volume alone; the workspace shape is an important aspect as well. In this paper, the geometric determination of the workspace for Delta robots is presented. The workspace (workspace volume and workspace shape) for the robots is studied systematically in ‘the physical model of the solution space’, which is a useful tool to express relationships between the performance criteria and all link lengths of one type of robotic mechanism. Performance atlases of the workspace volume for the robots are plotted in the physical model of the solution space. The characteristics of the distribution of the workspace shapes in the physical model of the solution space are presented as well. The physical model of the solution space presents a new method for the computer aided design (CAD) of robotic mechanisms. The results are very useful for obtaining the optimum design of robotic mechanisms.

Optimum design of a 4-PSS-PU redundant parallel manipulator based on kinematics and dynamics

2015 ◽  
Vol 230 (13) ◽  
pp. 2273-2284 ◽  
Author(s):  
Liping Wang ◽  
Binbin Zhang ◽  
Jun Wu
Keyword(s):  
Optimum Design ◽  
Parallel Manipulator ◽  
Design Space ◽  
Jacobian Matrix ◽  
Parallel Manipulators ◽  
Search Method ◽  
Kinematics And Dynamics ◽  
Performance Indices ◽  
Maximum Acceleration ◽  
High Acceleration

This paper presents an optimum design of a 4-PSS-PU redundant parallel manipulator by taking the workspace, conditioning performance, and acceleration into account. On the basis of rank of the Jacobian matrix, a method to directly find out the workspace is presented, rather than the search method. Based on the dynamic model, a maximum acceleration index is defined. The corresponding atlases of these performance indices are represented graphically in the established design space. Based on these atlases, the optimum design is performed and the optimum region is determined. It is expected to realize the high acceleration of parallel manipulators by using the optimum method.

scholarly journals Performance Analysis and Optimum Design of a Redundant Planar Parallel Manipulator

Symmetry ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 908 ◽  
Author(s):  
Xiaoyong Wu
Keyword(s):  
Optimum Design ◽  
Parallel Manipulator ◽  
Optical Design ◽  
Kinematic Model ◽  
Parallel Manipulators ◽  
Performance Comparison ◽  
Design Parameters ◽  
Redundant Manipulator ◽  
Symmetrical Structure ◽  
Planar Parallel Manipulator

This work presents a comprehensive performance evaluation and optimum design of a novel symmetrical 4-PPR (P indicates the prismatic joint, R denotes the revolute joint, and the letter with underline represents an active joint) redundant planar parallel manipulator. The kinematic model is established, upon which the inverse position and singularity are analyzed. Based on the evaluation of dexterity, velocity, and stiffness performance, the optimum region is achieved. With the optical design parameters, a case study for the analysis of dynamic behavior is conducted. Performance comparison between the redundant manipulator and another two non-redundant 3-PPR planar parallel manipulators, one with a Δ-shape symmetrical structure and the other with U-shape symmetrical structure, is presented. Simulation results reveal that the U-shape manipulator has the greatest velocity performance. Moreover, the redundant manipulator possesses the best dexterity, stiffness, and dynamic performance.

Global Approximation of Response Surfaces and Application to Design Sensitivity Analysis

1995 ◽  
Vol 48 (11S) ◽  
pp. S181-S188
Author(s):  
Hector A. Jensen
Keyword(s):  
Design Space ◽  
Design Sensitivity ◽  
Response Surfaces ◽  
Design Parameters ◽  
System Response ◽  
Global Approximation ◽  
Residual Function ◽  
Great Insight ◽  
Insight Into

An approach based on global approximations to obtain response surfaces of structural systems is presented. The response surfaces are then used to evaluate the sensitivity of the system by considering the global behavior of the system response when the design parameters vary within a bounded region. The formulation of the method is based on the determination of approximated response surfaces, which are computed by minimizing a residual function over the design space. Different coefficients of sensitivity are introduced to measure the global variability of the system response. A numerical example is considered in order to show the usefulness of this technique. Great insight into the behavior of the system can be gained using this methodology. Finally, some extensions of the present work are presented.

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