Automatic Structural Synthesis of the Whole Family of Planar 3-Degrees of Freedom Closed Loop Mechanisms

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Huafeng Ding ◽  
Peng Huang ◽  
Jingfang Liu ◽  
Andrés Kecskeméthy
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Synthesis Method ◽  
Synthesis Process ◽  
Structural Synthesis ◽  
Planar Mechanisms ◽  
Systematic Method ◽  
Automatic Synthesis ◽  
Heavy Load ◽  
Structure Representation

Conception of the kinematic structures with better performance has been a challenging, yet pivotal issue, since the beginning of the design of mechanisms or robots. This paper proposes a systematic method to synthesize and classify automatically all the valid kinematic structures of planar 3-DOF closed loop mechanisms or robots. First, after the structure representation graphs of planar mechanisms or robots are addressed, the unique representation of both contracted graphs and topological graphs is proposed and used to detect isomorphism in the synthesis process. Then the valid atlas database of the contracted graphs for planar 3-DOF closed loop mechanisms or robots up to 16-link is built. Based on the atlas database, an automatic synthesis method is proposed to synthesize all the kinematic structures of planar 3-DOF closed loop mechanisms or robots, and the complete atlas database with all the valid kinematic structures classified for planar 3-DOF closed loop mechanisms or robots up to 16-link is established. The creative design of 3-DOF heavy-load hydraulic robots is conducted to show the usefulness of the established atlas database.

scholarly journals Synthesis method of two translational compliant mechanisms with redundant actuation

2021 ◽  
Vol 12 (2) ◽  
pp. 983-995
Author(s):  
Shihua Li ◽  
Yajie Zhou ◽  
Yanxia Shan ◽  
Shuang Chen ◽  
Jinhan Han
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Compliant Mechanisms ◽  
Synthesis Method ◽  
Synthesis Process ◽  
Parallel Mechanisms ◽  
Synthesis Conditions ◽  
Compliant Parallel Mechanism ◽  
Atlas Method ◽  
Driving Stability

Abstract. In the fields of electronic packaging, micromanipulation, scanning, and two translational (2T) mechanisms are required, especially with high stiffness, for a large workspace, with good driving stability, and other occasions. Redundant actuators are required to improve the performance of the 2T compliant parallel mechanism. The novelty of the work is to propose a new method for the type synthesis of a 2T redundant actuated compliant parallel mechanism based on the freedom and constraint topology (FACT) approach and the atlas approach. The synthesis conditions are given, and the synthesis process is formulated. With this method, new 2T redundant actuated compliant parallel mechanisms are synthesized. Some new mechanisms have been synthesized, which enriches the compliant parallel mechanism configurations. Based on the atlas method, the synthesized mechanism is analyzed. The results verify the correctness and effective of the synthesis method. The method is also suitable for a type of synthesis of redundant actuated compliant parallel mechanisms with 3, 4, 5, and 6 degrees of freedom (DOF), respectively.

Indentification and Classification of Multi-Degree-of-Freedom and Multi-Loop Mechanisms

1992 ◽  
Author(s):  
Tyng Liu ◽  
Chung-Huang Yu
Keyword(s):  
Industrial Applications ◽  
Degree Of Freedom ◽  
Constrained Motion ◽  
Structural Synthesis ◽  
Planar Mechanisms ◽  
Systematic Method ◽  
Revolute Joints ◽  
Systematic Scheme ◽  
Actual Degree

Abstract This study concerns the degree-of-freedom, the arrangements of input and the type of mobility of multi-loop, multi-degree-of-freedom mechanisms. Firstly, “basic loops” is introduced, and a systematic scheme for identifying the actual degree-of-freedom of mechanisms is developed. The input, then, can be properly deployed, such that the mechanism has a totally constrained motion. Lastly, based on the input deployment, the mobility of mechanisms is classifed and identified into three types: total, partial and fractionated mobility. The procedure has been automated, and the atlas of all possible arrangements of input of up to eight-link planar mechanisms with only revolute joints is presented. The systematic method is helpful for the structural synthesis of multi-degree-of-freedom and multi-loop mechanisms, and for exploring their potential industrial applications.

Assur-Group Inferred Structural Synthesis for Planar Mechanisms

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Shujun Li ◽  
Hongguang Wang ◽  
Jian S. Dai
Keyword(s):  
Adjacency Matrix ◽  
Synthesis Method ◽  
Matrix Group ◽  
Structural Synthesis ◽  
Planar Mechanisms ◽  
Comprehensive List ◽  
Assur Group ◽  
The Given ◽  
First Time ◽  
Metamorphic Mechanisms

In order to obtain a comprehensive list of possible mechanisms with various choices of both R and P pairs and mechanism inversion of planar mechanisms, a new structural synthesis method is developed by integrating Assur groups (AGs) as elements in the newly developed group-based adjacency matrix. This extended adjacency matrix is proposed with the diagonal elements representing three fundamental elements as the frame link, driving link, AG and augmented AG (AAG) if metamorphic mechanisms are to be synthesized. The off-diagonal elements provide information on group combination and connection forms of the above three fundamental elements and that on the associated kinematic pairs. Based on the extended adjacency matrix, all assembly modes for the given AGs can be established and isomorphism mechanisms can be identified at the same time. Considering all types of the AGs in the extended adjacency matrix, group permutation and combination are used and connection forms are generated including variation of the driving link and mechanism inversion. The structural synthesis is then extending to generating a comprehensive list of types of mechanisms and illustrated by the synthesis for class II 6-bar planar mechanisms with both R and P pairs, generating a list of 588 types of mechanisms that are derived for the first time. The paper further applies the approach to metamorphic mechanisms, and obtained five connection forms of the 7-bar 2DOF metamorphic mechanisms.

Structural synthesis of a class of 3-DOF wrist mechanisms with redundantly-actuated closed-loop units

2015 ◽  
Vol 230 (2) ◽  
pp. 276-290 ◽  
Author(s):  
Haibo Qu ◽  
Yuefa Fang ◽  
Sheng Guo
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Screw Theory ◽  
Open Loop ◽  
Structural Synthesis ◽  
Constraint System ◽  
Redundantly Actuated ◽  
Rotational Degrees Of Freedom ◽  
Moving Platform

In this paper, a new method is proposed for the structural synthesis of a class of redundantly-actuated parallel wrists (RaPWs) with three rotational degrees of freedom of the moving platform and symmetrical structures based on screw theory. First, the new procedure for structural synthesis of RaPWs with closed-loop actuated unit is proposed and the constraint system of the moving platform of RaPWs is analyzed. Then, considering the inclusion relation between the primary constraint system and the limb constraint system, the type of kinematic limb is determined. The synthesis of type-1 and type-2 kinematic limbs is dealt with based on the obtained closed-loop actuated unit and open-loop sub-limb. Next, the RaPWs are synthesized and a number of new RaPWs have been identified. Finally, the condition for proper actuator selections of RaPWs is revealed, and one example is used to perform the validation.

The Spring-Connected Rigid Block Model Based Automatic Synthesis of Planar Linkage Mechanisms: Numerical Issues and Remedies

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Sang Jun Nam ◽  
Gang-Won Jang ◽  
Yoon Young Kim
Keyword(s):  
Closed Loop ◽  
Synthesis Method ◽  
Direct Application ◽  
Rigid Block ◽  
Block Model ◽  
Automatic Synthesis ◽  
Open Path ◽  
Synthesis Of Mechanisms ◽  
Input Motion ◽  
Linkage Synthesis

Because it is difficult to select in advance an appropriate linkage for converting an input motion to a desired output motion, a linkage synthesis method that does not require any baseline linkage would be preferred. To this end, an optimization-based linkage synthesis method that employs a spring-connected rigid block model has recently been suggested and applied for open-path problems. The objective of this study is to expand the method for the synthesis of more complex linkage mechanisms such as closed-loop linkages. Because the direct application of the method originally developed for open-path problems causes several numerical difficulties for closed-loop problems, an alternative optimization-based synthesis formulation is proposed in this investigation. The effectiveness of the suggested formulation is verified through several case studies including the synthesis of mechanisms generating closed paths.

Automatic Structural Synthesis of Planar Multiple Joint Kinematic Chains

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Huafeng Ding ◽  
Weijuan Yang ◽  
Peng Huang ◽  
Andrés Kecskeméthy
Keyword(s):  
Degrees Of Freedom ◽  
Characteristic Number ◽  
Structural Synthesis ◽  
Topological Graph ◽  
Topological Graphs ◽  
Systematic Method ◽  
Joint Kinematic ◽  
Kinematic Chains ◽  
Mechanical Products ◽  
First Time

It is of great importance in the conceptual creative design of mechanical systems to synthesize as many feasible kinematic structures of mechanisms as possible. However, the methods for the structural synthesis of multiple joint kinematic chains are seldom addressed in literature even though they are widely used in various mechanical products. This paper proposes an automatic method to synthesize planar multiple joint kinematic chains. First, the bicolor topological graph and the bicolor contracted graph are introduced to represent the topological structures of multiple joint kinematic chains. Then, the characteristic number string of bicolor topological graphs is proposed and used to efficiently detect isomorphism in the synthesis progress. Finally, a systematic method for the synthesis of kinematic chains with one multiple joint is proposed, and the whole families of multiple joint kinematic chains with up to 16 links and all possible degrees of freedom are synthesized for the first time.

Identification and Classification of Multi-Degree-of-Freedom and Multi-Loop Mechanisms

1995 ◽  
Vol 117 (1) ◽  
pp. 104-111 ◽  
Author(s):  
Tyng Liu ◽  
Chung-Huang Yu
Keyword(s):  
Industrial Applications ◽  
Degree Of Freedom ◽  
Constrained Motion ◽  
Structural Synthesis ◽  
Planar Mechanisms ◽  
Systematic Method ◽  
Revolute Joints ◽  
Systematic Scheme ◽  
Actual Degree

This study concerns the degree-of-freedom, the arrangements of input and the type of mobility of multi-loop, multi-degree-of-freedom mechanisms. Firstly, “basic loops” are introduced, and a systematic scheme for identifying the actual degree-of-freedom of mechanisms is developed. The input, then, can be properly deployed, such that the mechanism has a totally constrained motion. Lastly, based on the input deployment, the mobility of mechanisms is classifed and identified into three types: total, partial and fractionated mobility. The procedure has been automated, and the atlas of all possible arrangements of input of up to eight-link planar mechanisms with only revolute joints is presented. The systematic method is helpful for the structural synthesis of multi-degree-of-freedom and multi-loop mechanisms, and for exploring their potential industrial applications.

Type Synthesis of 1R1T Remote Center of Motion Mechanisms Based on Pantograph Mechanisms

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Huang Long ◽  
Yang Yang ◽  
Xiao Jingjing ◽  
Su Peng
Keyword(s):  
Fixed Point ◽  
Degrees Of Freedom ◽  
Motion Tracking ◽  
Closed Loop ◽  
Synthesis Method ◽  
Rigid Motion ◽  
Type Synthesis ◽  
Output Link ◽  
Geometric Transformations ◽  
Revolute Joints

The remote center of motion (RCM) mechanism is an important component of a minimally invasive surgery (MIS) robot. The feature of the RCM mechanism is that the output link can rotate around a fixed point and translate along an axis which passes the point; however, there is no revolute joint at the fixed point. The 3R1T RCM mechanism, which meets all the degrees-of-freedom (DOF) requirements of arbitrary MIS tools, can be assembled through many methods. An effective method is combining a planar closed-loop 1R1T RCM mechanism and two revolute joints. In this paper, we present an approach to construct 1R1T RCM mechanisms from pantograph mechanisms. First, pantograph mechanisms are divided into seven classifications according to the geometric transformations they represent. The concept of rigid motion tracking mechanism (RMTM) is proposed by combining two equivalent pantograph mechanisms. Then, a novel type synthesis method for 1R1T RCM mechanisms is discussed in detail, and it shows that a 1R1T RCM mechanism can be constructed by assembling an RMTM and a 1R1T mechanism. By this method, several examples are constructed.

scholarly journals A New Algorithm for Unique Representation and Isomorphism Detection of Planar Kinematic Chains with Simple and Multiple Joints

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 601
Author(s):  
Mahmoud Helal ◽  
Jong Wan Hu ◽  
Hasan Eleashy
Keyword(s):  
Degree Of Freedom ◽  
Synthesis Process ◽  
Structural Synthesis ◽  
Joint Configuration ◽  
Unique Representation ◽  
Kinematic Chains

In this work, a new algorithm is proposed for a unique representation for simple and multiple joint planar kinematic chains (KCs) having any degree of freedom (DOF). This unique representation of KCs enhances the isomorphism detection during the structural synthesis process of KCs. First, a new concept of joint degree is generated for all joints of a given KC based on joint configuration. Then, a unified loop array (ULA) is obtained for each independent loop. Finally, a unified chain matrix (UCM) is established as a unique representation for a KC. Three examples are presented to illustrate the proposed algorithm procedures and to test its validity. The algorithm is applied to get a UCM for planar KCs having 7–10 links. As a result, a complete atlas database is introduced for 7–10-link non-isomorphic KCs with simple or/and multiple joints and their corresponding unified chain matrix.

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