Type Synthesis of Parallel Mechanisms Having Two Rotations

2010 ◽  
Author(s):  
Feng Gao ◽  
Jialun Yang ◽  
Qiaode Jeffrey Ge
Keyword(s):  
Natural Law ◽  
Robotic Manipulators ◽  
Performance Criteria ◽  
Generalized Function ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
Gf Set ◽  
End Effectors

In the last few decades, researchers have proposed a few different methods to synthesize parallel mechanisms. In this paper, we propose both the natural law for kinematic mobility and the generalized function sets (GF set for short) which are used for the type synthesis of parallel mechanisms, particularly for those having two rotations. The natural law for kinematic mobility lays the foundation for the algorithms of the intersection of GF sets. Moreover, the GF sets are used for describing the performance criteria of the end-effectors of robotic manipulators in a clear and systematic way, including the mechanisms having two rotations. Finally, several novel parallel mechanisms having two rotations have been illustrated to show the effectiveness of the proposed methodology.

Type Synthesis of Parallel Mechanisms Having the Second Class GF Sets and Two Dimensional Rotations

2010 ◽  
Vol 3 (1) ◽  
Author(s):  
Feng Gao ◽  
Jialun Yang ◽  
Qiaode Jeffrey Ge
Keyword(s):  
Generalized Function ◽  
Two Dimensional ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
Gf Set ◽  
End Effectors

With the introduction of generalized function sets (GF set) to represent the characteristics of the end-effectors of parallel mechanisms, two classes of GF sets are proposed. The type synthesis of parallel mechanisms having the second class GF sets and two dimensional rotations, including 2-, 3-, and 4DOF parallel mechanisms, is investigated. First, the intersection algorithms for the GF sets are established via the axiom of two dimensional rotations. Second, the kinematic limbs with specific characteristics are designed according to the axis movement theorem. Finally, several parallel mechanisms having the second class GF sets and two dimensional rotations have been illustrated to show the effectiveness of the proposed methodology.

Structural Kinematics of Partially-Parallel Robotic Mechanisms

1987 ◽  
Author(s):  
M. Gaber Mohamed
Keyword(s):  
Carrying Capacity ◽  
Kinematic Chain ◽  
Performance Criteria ◽  
Load Carrying Capacity ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
Load Carrying ◽  
Parallel Kinematic ◽  
New Generation ◽  
Robotic Applications

Abstract This paper introduces a new generation of robotic mechanisms. Such mechanisms are intermediate between the familiar serial and the fully-parallel robotic mechanisms. They usually comprise several subassemblies that are serially connected to one another. Each subassembly is basically an over constrained fully parallel kinematic chain. Such mechanisms are called “Partially-Parallel Robotic Mechanisms.” A type synthesis of planar and spatial partially-parallel robotic mechanisms is performed. Several practical designs are then introduced and studied for future robotic applications. Several performance criteria of this type of mechanisms are discussed and compared with those of serial as well as fully-parallel robotic mechanisms. Partially-parallel mechanisms are superior than serial mechanisms in rigidity, strength precision positioning and load carrying capacity. Furthermore, they are relatively less complex and have larger range of motion than fully-parallel mechanisms.

Type synthesis of parallel mechanisms having the first class GF sets and one-dimensional rotation

Robotica ◽  
2011 ◽  
Vol 29 (6) ◽  
pp. 895-902 ◽  
Author(s):  
Jialun Yang ◽  
Feng Gao ◽  
Qiaode Jeffrey Ge ◽  
Xianchao Zhao ◽  
Weizhong Guo ◽  
...  
Keyword(s):  
Theoretical Foundation ◽  
Generalized Function ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
One Dimensional ◽  
The Law ◽  
2D And 3D

SUMMARYA method is presented for the type synthesis of a class of parallel mechanisms having one-dimensional (1D) rotation based on the theory of Generalized Function sets (GF sets for short), which contain two classes. The type synthesis of parallel mechanisms having the first class GF sets and 1D rotation is investigated. The Law of one-dimensional rotation is given, which lays the theoretical foundation for the intersection operations of GF sets. Then the kinematic limbs with specific characteristics are designed according to the 2D and 3D axis movement theorems. Finally, several synthesized parallel mechanisms have been sketched to show the effectiveness of the proposed methodology.

Type synthesis of parallel mechanisms capturing wave energy

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6689-6697
Author(s):  
Weixing Chen ◽  
Xiangdun Meng ◽  
Ye Li ◽  
Feng Gao
Keyword(s):  
Wave Energy ◽  
Generalized Function ◽  
Random Wave ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
Wave Energy Converters ◽  
Wide Range ◽  
Sets Theory ◽  
Procedural Method ◽  
Energy Converters

Wave energy is clean, renewable, and abundant, awaiting exploitation. A wide range of wave energy converters have been proposed so far. Oscillating body systems are an important class of wave energy converters. Many mechanisms have been invented to absorb the random wave energy. Nowadays, there is a lack of method to design the mechanism for oscillating body systems to extract the wave energy. Parallel mechanism has the advantages of high stiffness and high load, which are suitable for design of the mechanism for wave energy converters. In this paper, a procedural method based on the generalized function ( G F) sets theory is proposed to design parallel mechanisms to capture wave energy. Using this method, numerous parallel mechanisms have been obtained, which provides the foundation of the development of wave energy converters.

scholarly journals Type Synthesis of 1T2R Parallel Mechanisms Using Structure Coupling-Reducing Method

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Haitao Liu ◽  
Ke Xu ◽  
Huiping Shen ◽  
Xianlei Shan ◽  
Tingli Yang
Keyword(s):  
Explicit Form ◽  
Parallel Mechanism ◽  
Analytic Solutions ◽  
Forward Kinematics ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
Real Time Control ◽  
Time Control ◽  
Topological Characteristics ◽  
Zero Coupling

Abstract Direct kinematics with analytic solutions is critical to the real-time control of parallel mechanisms. Therefore, the type synthesis of a mechanism having explicit form of forward kinematics has become a topic of interest. Based on this purpose, this paper deals with the type synthesis of 1T2R parallel mechanisms by investigating the topological structure coupling-reducing of the 3UPS&UP parallel mechanism. With the aid of the theory of mechanism topology, the analysis of the topological characteristics of the 3UPS&UP parallel mechanism is presented, which shows that there are highly coupled motions and constraints amongst the limbs of the mechanism. Three methods for structure coupling-reducing of the 3UPS&UP parallel mechanism are proposed, resulting in eight new types of 1T2R parallel mechanisms with one or zero coupling degree. One obtained parallel mechanism is taken as an example to demonstrate that a mechanism with zero coupling degree has an explicit form for forward kinematics. The process of type synthesis is in the order of permutation and combination; therefore, there are no omissions. This method is also applicable to other configurations, and novel topological structures having simple forward kinematics can be obtained from an original mechanism via this method.

scholarly journals A New Method for Type Synthesis of 2R1T and 2T1R 3-DOF Redundant Actuated Parallel Mechanisms with Closed Loop Units

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Yongquan Li ◽  
Yang Zhang ◽  
Lijie Zhang
Keyword(s):  
Closed Loop ◽  
Screw Theory ◽  
Line Graph ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
Allocation Criteria ◽  
Grassmann Line Geometry ◽  
Moving Platform ◽  
Atlas Method

Abstract The current type synthesis of the redundant actuated parallel mechanisms is adding active-actuated kinematic branches on the basis of the traditional parallel mechanisms, or using screw theory to perform multiple getting intersection and union to complete type synthesis. The number of redundant parallel mechanisms obtained by these two methods is limited. In this paper, based on Grassmann line geometry and Atlas method, a novel and effective method for type synthesis of redundant actuated parallel mechanisms (PMs) with closed-loop units is proposed. Firstly, the degree of freedom (DOF) and constraint line graph of the moving platform are determined successively, and redundant lines are added in constraint line graph to obtain the redundant constraint line graph and their equivalent line graph, and a branch constraint allocation scheme is formulated based on the allocation criteria. Secondly, a scheme is selected and redundant lines are added in the branch chains DOF graph to construct the redundant actuated branch chains with closed-loop units. Finally, the branch chains that meet the requirements of branch chains configuration criteria and F&C (degree of freedom & constraint) line graph are assembled. In this paper, two types of 2 rotational and 1 translational (2R1T) redundant actuated parallel mechanisms and one type of 2 translational and 1 rotational (2T1R) redundant actuated parallel mechanisms with few branches and closed-loop units were taken as examples, and 238, 92 and 15 new configurations were synthesized. All the mechanisms contain closed-loop units, and the mechanisms and the actuators both have good symmetry. Therefore, all the mechanisms have excellent comprehensive performance, in which the two rotational DOFs of the moving platform of 2R1T redundant actuated parallel mechanism can be independently controlled. The instantaneous analysis shows that all mechanisms are not instantaneous, which proves the feasibility and practicability of the method.

Type Synthesis of Torsional Mass Dampers as Anti-Galloping Devices by Using Planar Four-Bar Mechanisms

2012 ◽  
Vol 215-216 ◽  
pp. 285-288 ◽  
Author(s):  
Jia Lun Yang ◽  
Kuan Jun Zhu ◽  
Bin Liu
Keyword(s):  
Power Grid ◽  
Robotic Manipulators ◽  
Type Synthesis ◽  
Safe Operation

The type synthesis of torsional mass dampers (TMDs for short) as anti-galloping devices is very import for the safe operation of power grid. In this paper, the TMDs are considered as passive robotic manipulators, with the aim of introducing planar four-bar mechanisms into the synthesis of TMDs. By utilizing one planar four-bar mechanism or two planar four-bar mechanisms in a single TMDs, 6 TMDs with symmetrical structures and 18 TMDs with non-symmetrical structures are synthesized, which may improve the reasonable applications of the TMDs for the solving the anti-galloping issue of power grid.

A Parallely Actuated Work Support Module for Reconfigurable Machining Systems

1998 ◽  
Author(s):  
Venkat Gopalakrishnan ◽  
Sridhar Kota
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Degrees Of Freedom ◽  
Mechanical Design ◽  
Performance Criteria ◽  
Machining Accuracy ◽  
Parallel Mechanisms ◽  
Element Analysis ◽  
Work Support ◽  
Reconfigurable Machining

Abstract In order to respond quickly to changes in market demands and the resulting product design changes, machine tool manufacturers must reduce the machine tool design lead time and machine set-up time. Reconfigurable Machine Tools (RMTs), assembled from machine modules such as spindles, slides and worktables are designed to be easily reconfigured to accommodate new machining requirements. The essential characteristics of RMTs are modularity, flexibility, convertibility and cost effectiveness. The goal of Reconfigurable Machining Systems (RMSs), composed of RMTs and other types of machines, is to provide exactly the capacity and functionality, exactly when needed. The scope of RMSs design includes mechanical hardware, control systems, process planning and tooling. One of the key challenges in the mechanical design of reconfigurable machine tools is to achieve the desired machining accuracy in all intended machine configurations. To meet this challenge we propose (a) to distribute the total number of degrees of freedom between the work-support and the tool and (b) employ parallely-actuated mechanisms for stiffness and ease of reconfigurability. In this paper we present a novel parallely-actuated work-support module as a part of an RMT. Following a brief summary of a few parallel mechanisms used in machine tool applications, this paper presents a three-degree-of-freedom work-support module designed to meet the machining requirements of specific features on a family of automotive cylinder heads. Inverse kinematics, dynamic and finite element analysis are performed to verify the performance criteria such as workspace envelope and rigidity. A prototype of the proposed module is also presented.

scholarly journals Type Synthesis of Fully-Decoupled Three-Rotational and One-Translational Parallel Mechanisms

10.5772/62684 ◽  
2016 ◽  
Vol 13 (2) ◽  
pp. 79 ◽  
Author(s):  
Yi Cao ◽  
Hai Chen ◽  
Youlei Qin ◽  
Kai Liu ◽  
Shuyi Ge ◽  
...  
Keyword(s):  
Parallel Mechanisms ◽  
Type Synthesis
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