Connectivity calculation-based automatic synthesis of planar multi-loop mechanisms

2021 ◽  
pp. 1-29
Author(s):  
Peng Huang ◽  
Huafeng Ding ◽  
Wenjian Yang ◽  
Gongyue Xu
Keyword(s):  
Synthesis Method ◽  
Connectivity Matrix ◽  
Automatic Method ◽  
Practical Application ◽  
Automatic Synthesis ◽  
End Effector ◽  
Kinematic Chains ◽  
Hybrid Code ◽  
Open Issue ◽  
Matrix Calculation

Abstract The creative design of kinematic structures with excellent performance remains an open issue in the quest for developing novel multi-loop mechanisms. This study presents an automatic method to synthesize all non-isomorphic planar multi-loop mechanisms satisfying the required connectivity between the base and the end-effector. First, based on the connectivity matrix calculation, all multi-loop mechanisms are generated from synthesized kinematic chains. Second, the concepts of perimeter, canonical and characteristic graphs of multi-color topological graphs are addressed to acquire the simplified characteristic hybrid code in order to eliminate isomorphic multi-loop mechanisms. Then, an automatic method to synthesize all non-isomorphic planar multi-loop mechanisms with the required connectivity between the base and the end-effector is provided. Third, a practical application of this synthesis method is illustrated by taking the mechanical arm of a face-shovel hydraulic excavator as an example to demonstrate the effectiveness of the method. Finally, the advantages of the proposed method are discussed and compared in detail.

Algorithm for computing the connectivity in planar kinematic chains and its application

2020 ◽  
pp. 095440622098050
Author(s):  
Wenjian Yang ◽  
Huafeng Ding ◽  
Andres Kecskemethy
Keyword(s):  
Minimum Distance ◽  
Distance Matrix ◽  
Individual Characteristics ◽  
Connectivity Matrix ◽  
Practical Application ◽  
Kinematic Chains ◽  
Main Work ◽  
The Face ◽  
Mobility Matrix ◽  
Connectivity Constraint

The number of synthesized kinematic chains usually is too large to evaluate individual characteristics of each chain. The concept of connectivity is useful to classify the kinematic chains. In this paper, an algorithm is developed to automatically compute the connectivity matrix in planar kinematic chains. The main work is to compute two intermediate parameters, namely the minimum mobility matrix and the minimum distance matrix. The algorithm is capable of dealing with both simple-jointed and multiple-jointed kinematic chains. The present work can be used to automatically determine kinematic chains satisfying the required connectivity constraint, and is helpful for the creative design of mechanisms. The practical application is illustrated by taking the face-shovel hydraulic excavator for instance.

Synthesis of Rectilinear Motion Generating Spatial Mechanism With Application to Automotive Suspension

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Jing-Shan Zhao ◽  
Fulei Chu ◽  
Zhi-Jing Feng
Keyword(s):  
Synthesis Method ◽  
Rectilinear Motion ◽  
End Effector ◽  
Kinematic Chains ◽  
Spatial Mechanism ◽  
Straight Line ◽  
Automotive Suspension ◽  
Generic Process ◽  
Wheel Track

This paper proposes a synthesis method for rectilinear motion generating spatial mechanism with application to automotive suspension. First, it presents a generic process to synthesize the kinematic chains of a mechanism with the prescribed mobility, and then it deduces the construction criteria of feasible kinematic chains for such a mechanism. The most outstanding advantages of the rectilinear motion generating spatial mechanism used as the independent automotive suspension are that the orientation and position parameters such as kingpin, caster, camber, axis distance, and wheel track are always maintained constant during jounce and rebound. These ideal characteristics are guaranteed by the particular rigid guidance mechanism whose end effector only has one translation along an exact straight line.

scholarly journals Structural synthesis of plane kinematic chain inversions without detecting isomorphism

2021 ◽  
Vol 12 (2) ◽  
pp. 1061-1071
Author(s):  
Jinxi Chen ◽  
Jiejin Ding ◽  
Weiwei Hong ◽  
Rongjiang Cui
Keyword(s):  
Mechanism Design ◽  
Adjacency Matrix ◽  
Synthesis Method ◽  
Kinematic Chain ◽  
Degree Of Freedom ◽  
Synthesis Methods ◽  
Creative Design ◽  
Structural Synthesis ◽  
Kinematic Chains

Abstract. A plane kinematic chain inversion refers to a plane kinematic chain with one link fixed (assigned as the ground link). In the creative design of mechanisms, it is important to select proper ground links. The structural synthesis of plane kinematic chain inversions is helpful for improving the efficiency of mechanism design. However, the existing structural synthesis methods involve isomorphism detection, which is cumbersome. This paper proposes a simple and efficient structural synthesis method for plane kinematic chain inversions without detecting isomorphism. The fifth power of the adjacency matrix is applied to recognize similar vertices, and non-isomorphic kinematic chain inversions are directly derived according to non-similar vertices. This method is used to automatically synthesize 6-link 1-degree-of-freedom (DOF), 8-link 1-DOF, 8-link 3-DOF, 9-link 2-DOF, 9-link 4-DOF, 10-link 1-DOF, 10-link 3-DOF and 10-link 5-DOF plane kinematic chain inversions. All the synthesis results are consistent with those reported in literature. Our method is also suitable for other kinds of kinematic chains.

A New Method of Design of Epicyclic Gear Trains

2013 ◽  
Vol 457-458 ◽  
pp. 707-712
Author(s):  
Pei Wen An ◽  
Zhong Liang Lv
Keyword(s):  
New Method ◽  
Combination Method ◽  
Engineering Practice ◽  
Type Number ◽  
Practical Application ◽  
Kinematic Chains ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Number Synthesis ◽  
Method Of Design

Epicyclic gear trains have been broadly applied in engineering practice. In this paper, kinematic chains (K.C.) with single-joint (S.J.) were applied to innovative synthesis of the epicyclic gear trains. The method of the innovative synthesis of the epicyclic gear trains was presented. Not only the epicyclic gear trains in common uses were obtained, but some new types of epicyclic gear trains that are got difficultly by means of conventional combination method were gained. Thereby, a new way has been offered for the innovative synthesis of the epicyclic gear trains, at the same time, a way has also been offered for practical application of some multi-link kinematic chains gained by using the theory of type-number synthesis of the K.C. with S.J.. Examples show that the method presented in this paper is right and feasible, and the method is efficient and practical for the innovative synthesis of the epicyclic gear trains.

A Synthesis Method for Placing Workpieces in RPR Planar Robotic Workcells in Which Large Rotations Are Required at the Workpiece

1996 ◽  
Author(s):  
K. D. Chaney ◽  
J. K. Davidson
Keyword(s):  
Reference Frame ◽  
Synthesis Method ◽  
Analytical Representation ◽  
New Method ◽  
Two Dimensional ◽  
End Effector ◽  
Radial Location ◽  
Practical Applications ◽  
Full Turn ◽  
Large Rotations

Abstract A new method is developed for determining both a satisfactory location of a workpiece and a suitable mounting-angle of the tool for planar RPR robots that can provide dexterous workspace. The method is an analytical representation of the geometry of the robot and the task, and is particularly well suited to applications in which the task requires large rotations of the end-effector. It is determined that, when the task requires that the end-effector rotate a full turn at just two locations and when the first or third joint in the robot is rotatable by one turn, then the radial location of the workpiece is fixed in the workcell but its angular location is not fixed. When the mounting-angle of the tool is also a variable, the method accommodates tasks in which the tool must rotate a full turn at three locations on the workpiece. The results are presented as coordinates of points in a two-dimensional Cartesian reference frame attached to the workcell. Consequently, a technician or an engineer can determine the location for the workpiece by laying out these coordinates directly in the workcell. Example problems illustrate the method. Practical applications include welding and deposition of adhesives.

Isomorphism Detection of Planar Kinematic Chains With Multiple Joints Using Information Theory

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Rajneesh Kumar Rai ◽  
Sunil Punjabi
Keyword(s):  
Information Theory ◽  
Structural Similarity ◽  
Transmission Efficiency ◽  
Necessary Condition ◽  
Connectivity Matrix ◽  
Kinematic Chains ◽  
Compact Size ◽  
Independent Loops ◽  
Link Connectivity ◽  
Structural Invariants

Isomorphism (structural similarity) of kinematic chains (KCs) of mechanisms is an important issue in the structural synthesis, which must be identified to avoid the duplicate structures. Duplication causes incorrect family size, i.e., distinct KCs with a given number of links (n) and degree of freedom (dof). Besides simple joints kinematic chains (SJKCs), multiple joints kinematic chains (MJKCs) are also widely used because of their compact size and the methods dealing with such KCs are few. The proposed method deals with two different structural invariants, i.e., primary structural invariants (provide only the necessary condition of isomorphism), such as link connectivity number (LCN) of all the links, link connectivity number of chain (CCN), joint connectivity number (JCN) of all the joints, and joint connectivity number of chain (JCNC), and secondary structural invariants (provide the sufficient condition of isomorphism), such as power transmission (P) and transmission efficiency (Te). Primary structural invariants are calculated using a new link–link connectivity matrix (LLCM), whereas secondary structural invariants are calculated using the concept of entropy of information theory. The method has been successfully tested for 10 and 11 links MJKCs (illustrative examples taken in the paper) and for the families of 18 MJKCs with 8 links, 2 MJs, 1-dof, and 3 independent loops; 22 MJKCs with 8 links, 1 MJ, 1-dof, and 3 independent loops; and 83 MJKCs with 9 links, 1 MJ, 2-dof, and 3 independent loops.

The Dimensional Synthesis of Spatial Cable-Driven Parallel Mechanisms

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
K. Azizian ◽  
P. Cardou
Keyword(s):  
Synthesis Method ◽  
Sufficient Condition ◽  
Nonlinear Program ◽  
Parallel Mechanisms ◽  
Dimensional Synthesis ◽  
End Effector ◽  
A Value ◽  
Null Value ◽  
Objective Value

This paper presents a method for the dimensional synthesis of fully constrained spatial cable-driven parallel mechanisms (CDPMs), namely, the problem of finding a geometry whose wrench-closure workspace (WCW) contains a prescribed workspace. The proposed method is an extension to spatial CDPMs of a synthesis method previously published by the authors for planar CDPMs. The WCW of CDPMs is the set of poses for which any wrench can be produced at the end-effector by non-negative cable tensions. A sufficient condition is introduced in order to verify whether a given six-dimensional box, i.e., a box covering point-positions and orientations, is fully inside the WCW of a given spatial CDPM. Then, a nonlinear program is formulated, whose optima represent CDPMs that can reach any point in a set of boxes prescribed by the designer. The objective value of this nonlinear program indicates how well the WCW of the resulting CDPM covers the prescribed box, a null value indicating that none of the WCW is covered and a value greater or equal to one indicating that the full prescribed workspace is covered.

Innovation Synthesis of Basic Configurationof Epicyclic Gear Trains with Three-Degrees of Freedom

2011 ◽  
Vol 199-200 ◽  
pp. 358-364
Author(s):  
Heng Bin Ren ◽  
Mao Lin Huang
Keyword(s):  
Degrees Of Freedom ◽  
Synthesis Method ◽  
Kinematic Chain ◽  
Practical Application ◽  
New Approach ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Train System ◽  
Three Degrees Of Freedom ◽  
Basic Configuration

Epicyclical gear trains with three-degrees of freedom have found its wide application as the development of new technique. Currently, nearly all domestic researches on epicyclical gear trains with three or more degrees of freedom are aimed at the practical application, and scare works systematically investigate basic configuration and synthesis of the train system. An innovation synthesis method is proposed based on the compound joint kinematic chain and the substitution of low pair with high pair for epicyclical gear trains with three-degrees of freedom, and the possible independent basic configurations of epicyclical gear trains with three-degrees of freedom are obtained by applying the proposed method and the utilization of the method is also discussed. The method provides not only a new approach for innovation synthesis of epicyclical gear trains but also a few basic configurations of epicyclical gear trains with three-degrees of freedom for practice design.

A Survey of One Class of 7-Jointed Serially Connected Robots: Type-Synthesis to Obtain Controllably Dexterous Workspace

1989 ◽  
Vol 111 (2) ◽  
pp. 163-175 ◽  
Author(s):  
J. K. Davidson
Keyword(s):  
Screw Theory ◽  
Kinematic Chain ◽  
Synthesis Process ◽  
Geometric Description ◽  
Type Synthesis ◽  
End Effector ◽  
Identification Process ◽  
Kinematic Chains ◽  
Five Axes

A type-synthesis process, which is based on screw theory and geometry, is developed to identify certain robots, each of which can provide controllably dexterous workspace of a tool-point. The identification process is confined to only those robots which control the motion of the end-effector with seven series-connected joints, the axes for the outermost three of which are concurrent. Forty six types of robots are so identified, and, for each, the results are (i) a suitable kinematic chain for the arm and (ii) suitable angle-dimensions for the links of the arm, where the angle-choices are limited to the values 0, ± π/2, and π. A geometric description of the dominant function for control is included. The same kinematic chains are surveyed for all possible parallel and right-angle arrangements of adjacent axes in the four links of the arm. Again utilizing screw theory, 160 robots are identified which do not posses full-cycle axis-dependence among some or all of the first five axes.

Solution Region Synthesis Method for Six Positions Synthesis of 5-SS Spatial Linkage

2016 ◽  
Author(s):  
Jianyou Han ◽  
Guangzhen Cui ◽  
Junjie Hu
Keyword(s):  
Systematic Approach ◽  
Synthesis Method ◽  
Degree Of Freedom ◽  
Dimensional Synthesis ◽  
End Effector ◽  
Region Method ◽  
Solution Region ◽  
The One

This paper presents a systematic approach to perform the dimensional synthesis of spatial 5-SS (spherical-spherical) link-ages for six specified positions of the end-effector. The dimensional synthesis equations for a SS link are formulated and solved. We synthesize five SS links to connect the base and end-effector, and then obtain the one-degree-of-freedom spatial 5-SS linkage, which can move through six specified positions. We use the solution region method to build the planar solution region expressing the linkages, due to there are infinite linkages for six positions synthesis. It is convenient to select the linkages from the solution region for designers. The applicability of the proposed approach is illustrated by the example.

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