General Formula of Mobility Calculation for Planar Mechanism

2012 ◽  
Vol 562-564 ◽  
pp. 654-659 ◽  
Author(s):  
Yan Dong Yang ◽  
Yi Tong Zhang
Keyword(s):  
Calculation Method ◽  
Mobility Analysis ◽  
Planar Mechanisms ◽  
Planar Mechanism ◽  
Link Group ◽  
New Concepts ◽  
General Constraints ◽  
Loop Constraint ◽  
New Formula ◽  
Virtual Loop

Deficiencies are existed for currently formulas of mobility calculation for planar mechanism. They are not suitable for planar mechanism with virtual constraints and the number of general constraints equal to 4. To solve the problem, the new concepts of virtual loop, virtual-loop constraint and virtual pair are defined to establish a general f ormula for DOF of planar mechanism; the calculation method for virtual-loop constraint and the mobility of link-group are also given. It is proved that the new formula is correct, general, simple and effective through the mobility analysis of several different kinds of planar mechanisms.

Determination of overconstraint and mobility analysis for planar mechanisms

2016 ◽  
Vol 230 (20) ◽  
pp. 3743-3754 ◽  
Author(s):  
Daxing Zeng ◽  
Wenjuan Lu ◽  
Zhen Huang
Keyword(s):  
Closed Loop ◽  
Degree Of Freedom ◽  
Mobility Analysis ◽  
Planar Mechanisms ◽  
New Concepts ◽  
Core Problem

The mobility(or degree of freedom) analysis of planar mechanisms is traditionally calculated using the Grübler–Kutzbach formula. However, this method often fails in practice due to overconstraint, which is a core problem in all mobility analysis. Analyzing the cause of overconstraint, it is presented that overconstraint in closed-loop mechanisms can be recognized by analyzing the relative movements of the two elements in a rigidity re-closure. A solution to determine the overconstraint in multiloop mechanisms is also proposed. In this method, each loop is opened and the overconstraint can be calculated when the loop is reclosed. A mobility analysis must begin by determining the overconstraint. However, given that most planar mechanisms do not have any overconstraint, it is important to identify rapidly whether overconstraint exists in a mechanism. This paper proposes a concise technique to determine the existence of overconstraint based on the concept of “Assur groups”. To simplify the process of mobility analysis, three new concepts and four relevant theories are introduced. In this paper, the proposed methodology is applied to several types of planar mechanisms, producing results in accordance with the prototype. This shows that the proposed methodology makes performing the mobility analysis of planar mechanisms, including complicated planar mechanisms, accurate, convenient, and fast.

Singularities of Single-DOF Spherical Mechanisms Identified by Means of Pole Axes’ Properties

2010 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Singularity Analysis ◽  
Systems Of Equations ◽  
Planar Mechanisms ◽  
Planar Mechanism ◽  
Geometric Conditions ◽  
Spherical Mechanisms ◽  
Spherical Mechanism ◽  
General Method

Instantaneous pole axes (IPAs) play, in spherical-mechanism kinematics, the same role as instant centers in planar-mechanism kinematics. IPA-based techniques have not been proposed yet for the singularity analysis of spherical mechanisms, even though instant-center-based algorithms have been already presented for planar mechanisms’ singularity analysis. This paper addresses the singularity analysis of single-dof spherical mechanisms by exploiting the properties of pole axes. A general method for implementing this analysis is presented. The presented method relies on the possibility of giving geometric conditions for any type of singularity, and it is the spherical counterpart of an instant-center-based algorithm previously proposed by the author for single-dof planar mechanisms. It can be used to generate systems of equations useful either for finding the singularities of a given mechanism or to synthesize mechanisms that have to match specific requirements about the singularities.

Kinematic and Dynamic Analysis of Planar Mechanisms by Means of the Cosmos Motion Program

2015 ◽  
Vol 816 ◽  
pp. 31-34
Author(s):  
Ján Vavro ◽  
Ján Vavro ◽  
Petra Kováčiková ◽  
Radka Bezdedová
Keyword(s):  
Dynamic Analysis ◽  
Planar Mechanisms ◽  
Planar Mechanism ◽  
Graphic Dependence ◽  
Angle Of Rotation

The paper presents a kinematic and dynamic analysis of a planar mechanism by means of the Cosmos Motion 2.85 program. Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and on the time.

Calculation of D-Section Classical V-Belt Power Rating in Different Reliability

2011 ◽  
Vol 338 ◽  
pp. 446-449 ◽  
Author(s):  
Chuan Qiong Sun ◽  
Ai Hua Ren ◽  
Guo Xing Sun ◽  
Yong De Liu
Keyword(s):  
Normal Distribution ◽  
Calculation Method ◽  
Accelerated Life Testing ◽  
New Method ◽  
Life Testing ◽  
Reliability Factor ◽  
Accelerated Life ◽  
Limit Stress ◽  
New Formula

The deficiencies of the Classical V-belt power rating calculation method in GB / T 11355 and GB / T 13575 is pointed. A new formula modifying the power rating with reliability factor is introduced. The data resulting from the step stress accelerated life testing of D-section Classical V-belt is transformed into equivalent limit stress data which is normal distribution, and then the limit stress of D-section Classical V-belt in different reliability and the corresponding reliability factor are determined, a calculating example by the new method is provided.

A Novel Underactuated Tetrahedral Mobile Robot

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Zhirui Wang ◽  
Yaobin Tian ◽  
Yan-an Yao
Keyword(s):  
Mobile Robot ◽  
Degrees Of Freedom ◽  
Mobility Analysis ◽  
Universal Joint ◽  
Tetrahedral Structure ◽  
Planar Mechanism ◽  
Series Of Experiments ◽  
Low Costs ◽  
Locomotion Analysis ◽  
Rolling Locomotion

This paper presents a novel underactuated tetrahedral mobile robot with 12 degrees-of-freedom (DOFs). The robot contains four vertices and six URU chains (where U represents a universal joint and R represents an actuated revolute joint). The tetrahedral structure makes the robot have continuous mobile ability at any posture. The mobility analysis has been made and demonstrates the feasibility of underactuated which demands fewer devices and low costs. A kind of rolling locomotion of the robot is proposed, and the feasibility of the locomotion is proved by the kinematic and locomotion analysis based on an equivalent planar mechanism. Finally, a prototype is manufactured and a series of experiments are performed to verify the mobile capability of the robot.

scholarly journals Solving the Kinematics of Planar Mechanisms by Dixon Determinant and a Complex-Plane Formulation

2000 ◽  
Vol 123 (3) ◽  
pp. 382-387 ◽  
Author(s):  
Charles W. Wampler
Keyword(s):  
Eigenvalue Problem ◽  
Complex Plane ◽  
Numerical Solutions ◽  
Minimal Size ◽  
Input Output ◽  
Planar Mechanisms ◽  
Planar Mechanism ◽  
Revolute Joints ◽  
Generalized Eigenvalue ◽  
General Method

This paper presents a general method for the analysis of any planar mechanism consisting of rigid links connected by revolute joints. The method combines a complex plane formulation [1] with the Dixon determinant procedure of Nielsen and Roth [2]. The result is simple to derive and implement, so in addition to providing numerical solutions, the approach facilitates analytical explorations. The procedure leads to a generalized eigenvalue problem of minimal size. Both input/output problems and the derivation of tracing curve equations are addressed, as is the extension of the method to treat slider joints.

Mass Center of Planar Mechanisms Using Auxiliary Parallelograms

1999 ◽  
Vol 121 (1) ◽  
pp. 166-168 ◽  
Author(s):  
A. Gokce ◽  
S. K. Agrawal
Keyword(s):  
Degrees Of Freedom ◽  
Center Of Mass ◽  
Mass Center ◽  
Planar Mechanisms ◽  
Physical Point ◽  
Planar Mechanism ◽  
Test Beds

Center of mass is an important property of a mechanism. In biomechanics, in many studies, one monitors the motion of this point. The center of mass has importance in development of gravity compensated exercise machines and test beds on earth that mimic the behavior of systems in space. In this paper, a method is described where auxiliary parallelograms are added to a planar mechanism to identify the location of the center of mass of the original mechanism. In this procedure, the original and the augmented mechanisms have the same number of degrees-of-freedom. During motion, the center of mass is a physical point which can be monitored or used for purposes motivated from the application.

Kinematic Structure and Functional Analysis of Shaft Couplings Involving Pode Joints

1983 ◽  
Vol 105 (4) ◽  
pp. 672-680 ◽  
Author(s):  
E. Akbil ◽  
T. W. Lee
Keyword(s):  
Functional Analysis ◽  
Degrees Of Freedom ◽  
Systematic Approach ◽  
Degree Of Freedom ◽  
Graph Representation ◽  
Kinematic Structure ◽  
Mobility Analysis ◽  
New Approaches ◽  
New Concepts ◽  
Basic Concepts

This paper introduces some basic concepts and new approaches regarding the kinematic structure and functional analysis of mechanisms. The theory and approach are illustrated on shaft couplings involving pode joints. Kinematic structure of pode joints is given and some new concepts, such as multiple contacting points and effective and idle degrees-of-freedom, are introduced. A systematic approach which includes a modified graph representation and a modified degree-of-freedom equation is presented. Using this approach the mobility analysis of a class of difficult and complex mechanisms can be treated. Several specific examples are presented to illustrate the basic theory.

Experimental Investigation on Flexure Performance of New Steeldeck-Concrete Thermal Insulation Composite Floor Slabs

2014 ◽  
Vol 584-586 ◽  
pp. 993-996
Author(s):  
Ping Zhou Cao ◽  
De Li ◽  
Rong Zhuo Lin
Keyword(s):  
Experimental Investigation ◽  
Bearing Capacity ◽  
Thermal Insulation ◽  
Calculation Method ◽  
Experimental Results ◽  
Floor Slabs ◽  
Flexural Bearing Capacity ◽  
New Formula ◽  
Steel Deck

A new Steel deck-concrete composite floor slabs was proposed that with the effect of het preservation and insulation, and the flexure performance of the slabs has been studied. Calculation method of flexural bearing capacity was put forward. Based on comparative and analysis experimental results, it has been verified that the applicability of new formula of flexural bearing capacity of the new slabs.

On the Input Joint Rotation Space and Mobility of Linkages

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Kwun-Lon Ting
Keyword(s):  
Visualization Tool ◽  
Mobility Analysis ◽  
Joint Rotation ◽  
Single Loop ◽  
Spatial Linkages ◽  
One To One ◽  
Spherical Linkages ◽  
Virtual Loop

This paper presents the concept and application of input joint rotation space of linkages and offers updates on the N-bar rotatability laws. A thorough discussion on the joint rotation space of single-loop planar five-bar linkages is first presented. The concept is then extended to spherical linkages and the generalization to N-bar linkages is discussed. It offers a visualization tool for the input joint rotatability and fills up a void in the N-bar rotatability laws regarding the coordination among multiple inputs. It explains the formation of branches and how to establish a one-to-one correspondence between the inputs and the linkage configurations. The applications to multiloop linkages and spatial linkages are highlighted with Stephenson six-bar linkages, geared linkages, and spatial RCRCR mechanisms. These examples exhibit simplicity and benefits of the proposed concept to the mobility analysis of diversified mechanisms. The concept of virtual loop in spatial linkages is proposed and demonstrated with simple RCRCR and Stephenson six-bar mechanisms.

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