Design and Analysis of a New Type Forging Manipulator

2017 ◽  
Author(s):  
Yanwen Li ◽  
Xiaofei Shi ◽  
Pengfei Mao ◽  
Yubo Cai ◽  
Maoling Wang
Keyword(s):  
Parallel Mechanism ◽  
Large Scale ◽  
Screw Theory ◽  
Synthesis Method ◽  
Degree Of Freedom ◽  
Lateral Movement ◽  
Kinematic Position ◽  
New Type ◽  
Forging Manipulator ◽  
Increasing Demand

Large-scale forging manipulator is the indispensable equipment in the operations of automated forging. Because of the increasing demand of forging manipulator, large and medium-sized enterprises pay more and more attention to the forging operation in production. Lower freedom parallel mechanism is obtained by using the constraint-synthesis method based on the screw theory, then a mechanism of forging manipulator is designed including raising and lowering, pitching, lateral swing, lateral movement, forth or back and clamp rotation. The new type forging manipulator is a hybrid serial-parallel mechanism. The degree of freedom of the parallel mechanism is calculated by using the modified Grübler-Kutzbach criterion, and then the degree of freedom of the machine is determined. Through closed geometric method, the kinematic position analysis is performed, and the correctness of the theoretical analysis results is verified.

Design and Analysis of a Hip Rehabilitation Mechanism

2013 ◽  
Vol 655-657 ◽  
pp. 1033-1037
Author(s):  
Ping Zhou ◽  
Qiang Wang ◽  
Li Ping Song ◽  
Shi De Zhang
Keyword(s):  
Hip Joint ◽  
Lower Limb ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Structural Features ◽  
Degree Of Freedom ◽  
Velocity Analysis ◽  
Rehabilitation Training ◽  
Electric Machinery ◽  
New Type

Studying the hip, a new type of parallel mechanism with three branches and 2DOF, 2-PSS/U asymmetric is proposed, which is based on the analysis of structural features of the human lower limb hip joint and the importance of human lower limb. A hip rehabilitation institutions, combined with Parallel Mechanism and electric machinery, is used for rehabilitation training. Calculating the degree of freedom of mechanism, verifying its degree of accuracy by means of screw theory, the Mechanism's forward position is evaluated, velocity analysis is made based on screw theory on the mechanism.

Research on the Configurations and Singularity of Serial-Parallel Mechanism

2011 ◽  
Vol 393-395 ◽  
pp. 265-268
Author(s):  
Jian Guo Luo ◽  
Mao Yan He
Keyword(s):  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Synthesis Method ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Spatial Mobility

Methods to analysis the DOF(degree of freedom) and singularity of pure serial and pure parallel manipulator, which can not be used to the serial-parallel manipulator directly, three type of practical topological units and one type of virtual topological unit adopted, Synthesis method of topological dimensionality of the spatial mobility of each topological unit integrated together, architectures of serial-paralle mechanism discussed, also the formula and process of its topological dimensionality of spatial mobility presented, singularity analysis of serial-parallel mechanism can be carried out based on the forgoing results.

scholarly journals Type Synthesis of 3-Translational Redundant Actuated Parallel Mechanisms With Closed-Loop Branch Chains Based On Graphical Approach

2021 ◽  
Author(s):  
Yongquan Li ◽  
Hong-Sheng Jiang ◽  
Tian-Yu Zheng ◽  
Ke-Long Xi ◽  
Han Jing ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Parallel Mechanism ◽  
Large Scale ◽  
Vibration Isolation ◽  
Closed Loop ◽  
Screw Theory ◽  
Simple Calculation ◽  
Parallel Mechanisms ◽  
Logistics Industry ◽  
Graphical Approach

Abstract The 3-translational parallel mechanism is widely used in industrial, medical, and military fields, among others. With the development of the national logistics industry, a pressing need for a kind of 3-translational parallel mechanism emerged. Such mechanisms have high stiffness and high bearing capacity and are used for cargo handling and sorting. A novel method based on the graphical approach was proposed for the synthesis of 3-translational redundancy actuated parallel mechanism with closed-loop branch chains. The new mechanism has four symmetrically arranged branch chains, which eases subsequent kinematics and dynamics analyses while providing good mechanical properties. Based on the graphical approach theory, according to the constraint number contained in the branch chain, two types of redundant driven branch chains with closed-loop structures were constructed. The first type includes rotation constraint in one direction, while the second type includes the rotation constraint in two directions. Based on various combinations of two branch chain types, their allocation schemes can be divided into two types. Moreover, said these two allocation schemes can be integrated into at least 500 and 400 types of 3-translational redundant actuated parallel mechanisms with closed-loop branch chains. Then, the degree of freedom properties of representative mechanisms were tested using the screw theory. A large number of novel mechanisms were integrated assessed using this method, and branch chains such mechanisms were symmetrically distributed. They have a strong bearing capacity, simple calculation, and control, and can be applied to the handling and sorting of goods, large-scale precision machine tools, and large construction machinery vibration isolation systems, among others.

scholarly journals A New Metamorphic Parallel Leg Mechanism with Reconfigurable Moving Platform

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yong Xu ◽  
Zheng Liang ◽  
Jiali Liu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Screw Theory ◽  
Degree Of Freedom ◽  
Walking Robots ◽  
Metamorphic Mechanism ◽  
Parallel Leg Mechanism ◽  
Moving Platform ◽  
Configuration Synthesis

This paper proposes the concept of full configuration state of metamorphic mechanism. Based on the concept, the configuration synthesis principle of metamorphic parallel mechanism is put forward. Firstly, a metamorphic parallel mechanism in full configuration state is synthesized, and then full configuration state evolves into a specific configuration state by increasing constraints or decreasing degrees of freedom. A reconfigurable moving platform based on the triple symmetric Bricard spatial closed-loop mechanism with a single degree of freedom is proposed. Based on this, a new method for switching motion configuration states of the metamorphic parallel mechanism is constructed. According to the configuration synthesis principle presented above, a novel metamorphic parallel mechanism that can switch between three- and four-degree-of-freedom is synthesized, and then the triple symmetric Bricard spatial closed-loop mechanism is used as the reconfigurable moving platform (that is, the reconfigurable foot of a walking robot) of the metamorphic mechanism, and thus, a novel metamorphic parallel leg mechanism is created. The screw theory is used to verify the degrees of freedom of the new type of metamorphic parallel leg. The proposed metamorphic parallel leg mechanism is expected to improve flexibility and adaptability of walking robots in unstructured environment.

scholarly journals Type Synthesis of Two DOF Hybrid Translational Parallel Manipulators

2016 ◽  
Vol 836 ◽  
pp. 48-53 ◽  
Author(s):  
Latifah Nurahmi ◽  
Stéphane Caro
Keyword(s):  
Screw Theory ◽  
Synthesis Method ◽  
Parallel Manipulators ◽  
Degree Of Freedom ◽  
Type Synthesis ◽  
In Series ◽  
Actuation Scheme ◽  
Two Degree Of Freedom

This paper introduces a methodology for the type synthesis of two degree-of-freedom hybrid translational manipulators with identical legs. The type synthesis method is based upon the screw theory. Three types of two degree-of-freedom hybrid translational manipulators with identical legs are identified based upon their wrench decomposition. Each leg of the manipulators is composed of a proximal module and a distal module mounted in series. The assembly conditions and the validity of the actuation scheme are also defined. Eventually, some novel two degree-of-freedom hybrid translational manipulators are synthesized with the proposed procedure.

A novel 4-RRCR parallel mechanism based on screw theory and its kinematics analysis

2012 ◽  
Vol 227 (9) ◽  
pp. 2039-2048 ◽  
Author(s):  
Sheng Guo ◽  
Congzhe Wang ◽  
Haibo Qu ◽  
Yuefa Fang
Keyword(s):  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Degree Of Freedom ◽  
Forward Kinematics ◽  
Kinematics Analysis ◽  
Elimination Method ◽  
Direct Kinematics

In this article, a novel 4-RRCR parallel mechanism is introduced based on screw theory, and its kinematics and singularity are studied systematically. First, the degree of freedom analysis is performed using the screw theory. The formulas for solving the inverse and direct kinematics are derived. Second, a recursive elimination method is proposed to solve the Jacobian matrix based on the algebra operation of reciprocal product. Then, three kinds of singularity, i.e. limb, platform, and actuation singularities are analyzed. Finally, the analysis proves that the proposed mechanism possesses two advantages of simple forward kinematics and no platform singularity.

Design and Kinematic Analysis of a 3RRlS Metamorphic Parallel Mechanism for Large-Scale Reconfigurable Space Multifingered Hand

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Chong Zhao ◽  
Hongwei Guo ◽  
Rongqiang Liu ◽  
Zongquan Deng ◽  
Bing Li
Keyword(s):  
Shape Memory Alloy ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Large Scale ◽  
Screw Theory ◽  
Kinematic Equation ◽  
Aerospace Application ◽  
Parasitic Motion ◽  
Geometric Conditions ◽  
In Series

Capturing noncooperative targets in space has great prospects for aerospace application. In this work, the knuckle unit of a large-scale reconfigurable space multifingered hand (LSRSMFH) for multitask requirements is studied. A plurality of knuckle units is connected in series to form a finger of the LSRSMFH. First, the lockable spherical (lS) joint, a new metamorphic joint that can function as a Hooke (lS1) or spherical (lS2) joint and is driven by shape memory alloy (SMA) material, is proposed. Based on the lS joint, this paper presents a new metamorphic parallel mechanism (MPM) (i.e., 3RRlS MPM), which has four configurations, namely, 3RRlS1, 3RRlS2, 2RRlS1-RRlS2, and 2RRlS2-RRlS1 configuration. The degree-of-freedom (DOF), overconstraint, and parasitic motion of the 3RRlS MPM are analyzed using screw theory, of which the DOF can be changed from 1 to 3. The 3RRlS1 configuration has a virtual constraint, and the 3RRlS2 configuration has parasitic motions. The results indicate that the mechanism motion screws can qualitatively represent the mechanism parasitic motions, and it is verified by deriving the kinematic equation of the 3RRlS MPM based on its spatial geometric conditions, the workspace of the 3RRlS MPM is further solved. The kinematic analysis indicates that the 3RRlS MPM can realize the folding, capturing, and reconfiguring conditions of the LSRSMFH.

Kinematic Analysis of A Novel 2-UPU/2-URU Parallel Mechanism

2011 ◽  
Vol 317-319 ◽  
pp. 469-474
Author(s):  
Shi Hua Li ◽  
Zhi Song Wang ◽  
Chang Cheng Yu ◽  
Wen Gong
Keyword(s):  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Degree Of Freedom ◽  
Influence Coefficient ◽  
Performance Curve ◽  
Kinematics Analysis

Abstract. In this paper, a novel type of 2-UPU/2-URU asymmetric parallel mechanism is put forward, the degree of freedom and kinematics characteristics of the mechanism is analyzed. Firstly, based on screw theory, the degree of freedom of the mechanism is analyzed by using modified Grübler-Kutzbach formula of Degree of Freedom, the method is ingenious and simple. Then the kinematics analysis is done. Finally, the velocity and acceleration of the mechanism is analyzed by combining kinematic influence coefficient theory with imaginary mechanism method, and draw the velocity and acceleration performance curve of the mechanism with the MATLAB. This paper lays the foundation for further research of the parallel mechanism.

Kinematic Design of a Novel Two Degree-of-Freedom Parallel Mechanism for Minimally Invasive Surgery

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Wen-ao Cao ◽  
Shi-jie Xu ◽  
Kun Rao ◽  
Tengfei Ding
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Degree Of Freedom ◽  
Compact Structure ◽  
Minimally Invasive Surgical ◽  
Physical Prototype ◽  
Two Degree Of Freedom ◽  
Surgical Manipulator

A novel two degree-of-freedom (2-DOF) parallel mechanism with remote center-of-motion (RCM) is proposed for minimally invasive surgical applications in this paper. A surgical manipulator with expected three-rotation and one-translation (3R1T) outputs can be obtained by serially connecting a revolute pair (R) and a prismatic pair (P) to the mechanism. First, kinematics of the new mechanism is analyzed and the corresponding velocity Jacobin matrix is established. Then, singularity identification of the mechanism is performed based on screw theory. Further, main dimensions of the mechanism are designed, and a physical prototype is developed to verify the effectiveness of executing RCM. The proposed mechanism has relatively simple kinematics, and can obtain a noninterference and nonsingularity cone workspace with the top angle of 60 deg based on a compact structure.

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