Selecting Kinematic Structures of Parallel Manipulators Using Symmetry and Connectivity

2015 ◽  
Author(s):  
Roberto Simoni ◽  
Henrique Simas ◽  
Daniel Martins
Keyword(s):  
Conceptual Design ◽  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Connectivity Matrix ◽  
Early Stages

This paper presents an application of symmetry and connectivity to select kinematic structures of parallel manipulators. One kinematic chain can originate several mechanisms and each mechanism can originate several parallel manipulators and, in early stages of conceptual design, it is difficult to decide what is the most promising one. Hunt [1] introduced the concept of connectivity and, since then, the connectivity has been used as an important parameter to select the most appropriated parallel manipulators to develop determined task. However, it is difficult to analyze non isomorphic parallel manipulators from the connectivity matrix. In this sense, in this paper, we apply symmetry to reduce the set of parallel manipulators to a manageable few with the desired connectivity. As a result, all promising parallel manipulators originating from a kinematic chain can be analyzed without isomorphisms.

scholarly journals A CONCEPTUAL DESIGN FOR RECONFIGURABLE ROBOTS

2011 ◽  
Author(s):  
Farhad Aghili
Keyword(s):  
Conceptual Design ◽  
Mechanical Design ◽  
Twist Angle ◽  
Kinematic Chain ◽  
Control Synthesis ◽  
Kinematics Analysis ◽  
New Paradigm ◽  
Passive Joint ◽  
Reconfigurable Robots

The paper presents a new paradigm and conceptual design for reconfigurable robots. Unlike conventional reconfigurable robots, our design doesn't achieve reconfigurability by utilizing modular joints. But the robot is equipped with passive joints, i.e. joints with no actuator or sensor, which permit changing the Denavit-Hartenberg (DV) parameters such as the arm length, and the twist angle. The passive joints are controllable when the robot forms a closed kinematic chain. Also each passive joint is equipped with a built-in brake mechanism which is normally locked but it can be released whenever changing of the parameters is required. Kinematics analysis of such a robot plus control synthesis and mechanical design of the brake mechanism are described.

Type Synthesis of 3-DOF Spherical Parallel Manipulators Based on Screw Theory1

2004 ◽  
Vol 126 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Xianwen Kong ◽  
Cle´ment M. Gosselin
Keyword(s):  
Parallel Manipulator ◽  
Screw Theory ◽  
General Procedure ◽  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Type Synthesis ◽  
Validity Condition ◽  
First Time ◽  
Spherical Parallel Manipulator ◽  
Selection Of

A spherical parallel manipulator (SPM) refers to a 3-DOF (degree-of-freedom) parallel manipulator generating 3-DOF spherical motion. A method is proposed for the type synthesis of SPMs based on screw theory. The wrench systems of a spherical parallel kinematic chain (SPKC) and its legs are first analyzed. A general procedure is then proposed for the type synthesis of SPMs. The type synthesis of legs for SPKCs, the type synthesis of SPKCs, as well as the selection of inputs of SPMs are dealt with in sequence. An input validity condition of SPMs is proposed. SPKCs with and without inactive joints are synthesized. The number of overconstraints of each SPKC is also given. The phenomenon of dependent joint groups in an SPKC is revealed for the first time.

Evaluation of Topological Properties of Parallel Manipulators Based on the Topological Characteristic Indexes

Robotica ◽  
2019 ◽  
Vol 38 (8) ◽  
pp. 1381-1399 ◽  
Author(s):  
Huiping Shen ◽  
Ting-Li Yang ◽  
Ju Li ◽  
Dan Zhang ◽  
Jiaming Deng ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Design Guidelines ◽  
Design Knowledge ◽  
Topological Properties ◽  
Topological Characteristic ◽  
Actuated Joints ◽  
Selection Of

SUMMARYThe topological structure of a parallel manipulator (PM) determines its intrinsic topological properties (TPs). The TPs further determine essential kinematic and dynamic properties of the mechanism. TPs can be expressed through topological characteristics indexes (TCI). Therefore, defining a set of TCIs is an important issue to evaluate the TPs of PMs. This article addresses the evaluation of topological properties (ETP) of PMs based on TCI. A general and effective ETP method for PMs is proposed. Firstly, 12 TCIs are proposed, including 8 quantitative TCIs, that is, position and orientation characteristics sets (POC), dimension of the POC set, degrees of freedom (DOF), number of independent displacement equations, types and number of an Assur kinematic chain (AKC), coupling degrees of the AKCs, degrees of redundancy and the number of overs; as well as 4 qualitative TCIs, that is, selection of actuated joints, identification of inactive joints, DOF type and Input–Output motion decoupling. Secondly, the ETP method is illustrated by evaluating some well-known PMs including the Delta, Tricept, Exechon, Z3, H4 and the Gough–Stewart platform manipulators, as well as 28 other typical PMs. Via the ETP analysis of these mechanisms also some valuable design knowledge is derived and guidelines for the design of PMs are established. Finally, a 5-DOF decoupled hybrid spraying robot is developed by applying the design knowledge and the design guidelines derived from the ETP analysis.

A Review of Reliability Principles in Conceptual Design

2011 ◽  
Vol 199-200 ◽  
pp. 583-586
Author(s):  
Yu Lian Cui ◽  
Wei Wu
Keyword(s):  
Conceptual Design ◽  
High Reliability ◽  
Reliability Prediction ◽  
Design Stage ◽  
Design Phase ◽  
Product Reliability ◽  
Design Decisions ◽  
Early Stages ◽  
Conceptual Design Phase

In this paper an attempt has been made to identify certain useful parts that will assist to consider reliability during conceptual design phase. The aim is to provide some thoughts and a toolkit for addressing reliability during the early stages of design, influencing design decisions and product reliability, and reducing the relying on the reliability prediction and expensive experiments in later design stage. Therefore high reliability can be cost-effectively achieved.

The differential calculus of screws: Theory, geometrical interpretation, and applications

2009 ◽  
Vol 223 (6) ◽  
pp. 1449-1468 ◽  
Author(s):  
J J Cervantes-Sánchez ◽  
J M Rico-Martínez ◽  
G González-Montiel ◽  
E J González-Galván
Keyword(s):  
Differential Calculus ◽  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Higher Order ◽  
Abstract Concepts ◽  
Serial Manipulators ◽  
Kinematic Chains ◽  
Finite Displacements ◽  
Typical Shape ◽  
Derivatives Of

This article presents a novel and original formula for the higher-order time derivatives, and also for the partial derivatives of screws, which are successively computed in terms of Lie products, thus leading to the automation of the differentiation process. Through the process and, due to the pure geometric nature of the derivation approach, an enlightening physical interpretation of several screw derivatives is accomplished. Important applications for the proposed formula include higher-order kinematic analysis of open and closed kinematic chains and also the kinematic synthesis of serial and parallel manipulators. More specifically, the existence of a natural relationship is shown between the differential calculus of screws and the Lie subalgebras associated with the expected finite displacements of the end effector of an open kinematic chain. In this regard, a simple and comprehensible methodology is obtained, which considerably reduces the abstraction level frequently required when one resorts to more abstract concepts, such as Lie groups or Lie subalgebras; thus keeping the required mathematical background to the extent that is strictly necessary for kinematic purposes. Furthermore, by following the approach proposed in this article, the elements of Lie subalgebra arise in a natural way — due to the corresponding changes in screws through time — and they also have the typical shape of the so-called ordered Lie products that characterize those screws that are compatible with the feasible joint displacements of an arbitrary serial manipulator. Finally, several application examples — involving typical, serial manipulators — are presented in order to prove the feasibility and validity of the proposed method.

Classification of 6-SPS Parallel Manipulators According to Their Components

2000 ◽  
Author(s):  
Xianwen Kong ◽  
Clément M. Gosselin
Keyword(s):  
Parallel Manipulator ◽  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Rigid Bodies ◽  
Type Synthesis ◽  
Forward Displacement ◽  
Quadratic Equations ◽  
Straight Lines ◽  
Forward Displacement Analysis

Abstract The complexity of the forward displacement analysis (FDA) of 6-SPS parallel manipulators1 varies to a great extent with the change of their geometric parameters. This paper presents a classification of the 6-SPS parallel manipulators according to their components. At first, we give the components for the 6-SPS parallel manipulator. A component refers to a part of the 6-SPS kinematic chain in which the number of actuators is equivalent to the degree of freedom. In addition to the commonly used rigid bodies, points and (straight) lines are also taken as elements of the components. Type synthesis of the 6-SPS parallel manipulators is then performed. The influence of the types of components on the maximal numbers of configurations and the degrees of the characteristic polynomials of the 6-SPS parallel manipulators is then revealed. The number of redundant sensors needed to reduce the FDA of 6-SPS parallel manipulators to the solution of several univariate quadratic equations in sequence based on the component method is also presented.

SYNTHESIS OF STATICALLY DETERMINED ISOTROPIC PARALLEL MANIPULATORS OF THE PANTOPTERON TYPE

2020 ◽  
Author(s):  
Andrey Tolstosheev ◽  
Vyacheslav Tatarincev
Keyword(s):  
Kinematic Chain ◽  
Parallel Manipulators

Isotropic parallel manipulators are considered. The analysis of the structure and kinematics of the parallel translational directional manipulator Pantopteron is carried out. It was found that the Pantopteron mechanism, in the kinematic chain of which pantographs are included in order to increase the speed, contains redundant links and is statically indeterminate. Structural schemes of statically definable parallel manipulators of the Pantopteron type have been developed and proposed.

Metrics for Assessing Design Freedom and Information Certainty in the Early Stages of Design

1998 ◽  
Vol 120 (4) ◽  
pp. 628-635 ◽  
Author(s):  
T. W. Simpson ◽  
D. Rosen ◽  
J. K. Allen ◽  
F. Mistree
Keyword(s):  
Conceptual Design ◽  
Design Knowledge ◽  
Engineering Systems ◽  
Point Sets ◽  
Design Specifications ◽  
Early Stages ◽  
Per Se ◽  
Level Design ◽  
Primary Focus ◽  
Design Freedom

Our primary focus in this paper is on open engineering systems. Developing ranged sets (as opposed to point sets) of top-level design specifications is a means to enhance openness and system flexibility by increasing design knowledge while maintaining design freedom. Consequently, our secondary focus in this paper is on metrics for assessing the design freedom and information certainty associated with a ranged set of top-level design specifications. As a demonstration, these metrics are applied to an example problem, namely, the conceptual design of a family of aircraft. Our emphasis in this paper is on introducing open engineering systems and metrics for design freedom and information certainty, and not on the example, per se.

scholarly journals Estimating the Impact of Design Automation: The Influence of Knowledge on Potential Estimation

2019 ◽  
Vol 1 (1) ◽  
pp. 1943-1952
Author(s):  
Eugen Rigger ◽  
Alexander Lutz ◽  
Kristina Shea ◽  
Tino Stankovic
Keyword(s):  
Comparative Study ◽  
Conceptual Design ◽  
Design Automation ◽  
Careful Attention ◽  
Design Practice ◽  
Industrial Case Study ◽  
Early Stages ◽  
Sufficient Knowledge ◽  
The Impact

AbstractAssessing the impact of design automation on design practice prior to its implementation is difficult and subject to uncertainties. One reason for this is the designers' lack of knowledge about design automation. In this work, an industrial case study focusing on conceptual design of hydraulic circuits is conducted to assess the impact of the designers' knowledge on design automation potential estimation. In particular, the impact of demonstrating a prototypical implementation of a design automation application is investigated as a means to enhance the designers' knowledge about design automation. In this respect, a given set of metrics is rated twice to enable a comparative study: prior to and after introducing the design automation prototype. The yielded results show that the knowledge impacts the rating and supports reliability of potential estimation. Further, it is shown that designers acknowledge design automation potential for the early stages of design given sufficient knowledge about design automation. Yet, the results also indicate that careful attention needs to be put on the aspects covered by the prototype in order to avoid biasing participants.

Dexterous Workspace of n-PRRR Planar Parallel Manipulators

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
André Gallant ◽  
Roger Boudreau ◽  
Marise Gallant
Keyword(s):  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Divergence Theorem ◽  
End Effector ◽  
Kinematic Chains ◽  
Prismatic Joint ◽  
Planar Surfaces ◽  
Revolute Joints ◽  
Gauss Divergence Theorem ◽  
Planar Parallel Manipulators

In this work, a method is presented to geometrically determine the dexterous workspace boundary of kinematically redundant n-PRRR (n-PRRR indicates that the manipulator consists of n serial kinematic chains that connect the base to the end-effector. Each chain is composed of two actuated (therefore underlined) joints and two passive revolute joints. P indicates a prismatic joint while R indicates a revolute joint.) planar parallel manipulators. The dexterous workspace of each nonredundant RRR kinematic chain is first determined using a four-bar mechanism analogy. The effect of the prismatic actuator is then considered to yield the workspace of each PRRR kinematic chain. The intersection of the dexterous workspaces of all the kinematic chains is then obtained to determine the dexterous workspace of the planar n-PRRR manipulator. The Gauss divergence theorem applied to planar surfaces is implemented to compute the total dexterous workspace area. Finally, two examples are shown to demonstrate applications of the method.

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