A New Family of Deployable Mechanisms Derived From Two-Layer and Two-Loop Spatial Linkages With Five Revolute Pair Coupling Chains

2017 ◽  
Vol 9 (6) ◽  
Author(s):  
Wen-ao Cao ◽  
Donghao Yang ◽  
Huafeng Ding
Keyword(s):  
Structural Characteristics ◽  
Degree Of Freedom ◽  
Single Loop ◽  
New Family ◽  
Serial Chain ◽  
Spatial Linkages ◽  
Application Requirements ◽  
Pair Coupling

This paper aims to construct a novel family of deployable mechanisms from a class of two-layer and two-loop spatial linkages, each of which consists of an eight revolute pair (8R) single-loop linkage connected by a 5R serial chain. First, structural characteristics of the class of linkages as deployable units are analyzed and illustrated. Then, the two-layer and two-loop spatial linkages with 5R chains satisfying the structural characteristics are systematically synthesized. Mobile assembly modes between deployable units are established based on degree-of-freedom (DOF) analysis. Finally, a family of single DOF deployable mechanisms is constructed based on the synthesized deployable units and the established assembly modes. The derived deployable mechanisms have the characteristic of the umbrella-like structure, and they have various mesh shapes, which can meet different kinds of application requirements.

Velocity, Acceleration, and Static-Force Analyses of Spatial Linkages

1965 ◽  
Vol 32 (4) ◽  
pp. 903-910 ◽  
Author(s):  
J. Denavit ◽  
R. S. Hartenberg ◽  
R. Razi ◽  
J. J. Uicker
Keyword(s):  
Virtual Work ◽  
Algebraic Method ◽  
Degree Of Freedom ◽  
Static Force ◽  
Virtual Displacement ◽  
Single Loop ◽  
Loop Equation ◽  
The Matrix ◽  
Spatial Linkages

The algebraic method using 4 × 4 matrices is extended to the analysis of velocities, accelerations, and static forces in one-degree-of-freedom, single-loop, spatial linkages consisting of revolute and prismatic pairs, either singly or in combination. The methods are well suited for machine calculations and have been tested on a number of examples, one of which is presented. Velocities and accelerations are obtained by differentiation of the matrix-loop or position equation. Static forces are found by combining the method of virtual work with the matrix-loop equation to relate the virtual displacement of the load to given virtual deformations of the links.

Seven-Position Synthesis of a Spatial Eight-Bar Linkage by Constraining a TRS Serial Chain

2009 ◽  
Author(s):  
Gim Song Soh ◽  
J. Michael McCarthy
Keyword(s):  
Degree Of Freedom ◽  
Upper Arm ◽  
End Effector ◽  
Serial Chain ◽  
Position Synthesis ◽  
Two Degree Of Freedom ◽  
Puma Robot

In this paper, we use seven-position synthesis to add four TS constraints to a TRS serial chain robot and obtain a two degree-of-freedom spatial eight-bar linkage. The TRS chain is an elbow manipulator, similar to a PUMA robot. We synthesize a TS dyad to connect the base of the robot to its forearm, and then we synthesize three TS dyads that connect the upper arm of the robot to its end-effector. The result is a two degree-of-freedom spatial eight-bar linkage that moves through seven prescribed positions. It consists of a TRST loop supporting a 3TS-RS platform, which we denote as a TS-TRS-3TS spatial linkage. We formulate and solve the design equations for the TS dyads, and analyze the resulting eight-bar linkage. An example demonstrates our results.

A Novel Method for Constructing Multi-Mode Deployable Polyhedron Mechanisms Using Symmetric Spatial RRR Compositional Units

2018 ◽  
Author(s):  
Jieyu Wang ◽  
Xianwen Kong
Keyword(s):  
Kinematic Chain ◽  
Degree Of Freedom ◽  
Single Loop ◽  
Kinematic Chains ◽  
The Third ◽  
Motion Modes ◽  
3D Printed ◽  
Novel Method ◽  
Multi Mode ◽  
Motion Mode

A novel construction method is proposed to construct multimode deployable polyhedron mechanisms (DPMs) using symmetric spatial RRR compositional units, a serial kinematic chain in which the axes of the first and the third revolute (R) joints are perpendicular to the axis of the second R joint. Single-loop deployable linkages are first constructed using RRR units and are further assembled into polyhedron mechanisms by connecting single-loop kinematic chains using RRR units. The proposed mechanisms are over-constrained and can be deployed through two approaches. The prism mechanism constructed using two Bricard linkages and six RRR limbs has one degree-of-freedom (DOF). When removing three of the RRR limbs, the mechanism obtains one additional 1-DOF motion mode. The DPMs based on 8R and 10R linkages also have multiple modes, and several mechanisms are variable-DOF mechanisms. The DPMs can switch among different motion modes through transition positions. Prototypes are 3D-printed to verify the feasibility of the mechanisms.

scholarly journals An Alternate Generalized Odd Generalized Exponential Family with Applications to Premium Data

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2064
Author(s):  
Sadaf Khan ◽  
Oluwafemi Samson Balogun ◽  
Muhammad Hussain Tahir ◽  
Waleed Almutiry ◽  
Amani Abdullah Alahmadi
Keyword(s):  
Exponential Family ◽  
Simulation Analysis ◽  
Structural Characteristics ◽  
Stochastic Ordering ◽  
Quantile Function ◽  
Risk Theory ◽  
Data Sets ◽  
Exponential Distributions ◽  
New Family ◽  
Lehmann Alternative

In this article, we use Lehmann alternative-II to extend the odd generalized exponential family. The uniqueness of this family lies in the fact that this transformation has resulted in a multitude of inverted distribution families with important applications in actuarial field. We can characterize the density of the new family as a linear combination of generalised exponential distributions, which is useful for studying some of the family’s properties. Among the structural characteristics of this family that are being identified are explicit expressions for numerous types of moments, the quantile function, stress-strength reliability, generating function, Rényi entropy, stochastic ordering, and order statistics. The maximum likelihood methodology is often used to compute the new family’s parameters. To confirm that our results are converging with reduced mean square error and biases, we perform a simulation analysis of one of the special model, namely OGE2-Fréchet. Furthermore, its application using two actuarial data sets is achieved, favoring its superiority over other competitive models, especially in risk theory.

A New Family of Bricard-Derived Deployable Mechanisms

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Hailin Huang ◽  
Bing Li ◽  
Jianyang Zhu ◽  
Xiaozhi Qi
Keyword(s):  
Large Volume ◽  
Computer Aided Design ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
New Family ◽  
Revolute Joints ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

This paper proposes a new family of single degree of freedom (DOF) deployable mechanisms derived from the threefold-symmetric deployable Bricard mechanism. The mobility and geometry of original threefold-symmetric deployable Bricard mechanism is first described, from the mobility characterstic of this mechanism, we show that three alternate revolute joints can be replaced by a class of single DOF deployable mechanisms without changing the single mobility characteristic of the resultant mechanisms, therefore leading to a new family of Bricard-derived deployable mechanisms. The computer-aided design (CAD) models are used to demonstrate these derived novel mechanisms. All these mechanisms can be used as the basic modules for constructing large volume deployable mechanisms.

scholarly journals Design of a Spatial RPR-2SS Valve Mechanism

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Peter L. Wang ◽  
Ulrich Rhem ◽  
J. Michael McCarthy
Keyword(s):  
Tunnel Boring Machine ◽  
Degree Of Freedom ◽  
Valve Mechanism ◽  
Kinematic Synthesis ◽  
Soil Conditioning ◽  
Spatial Mechanism ◽  
Tunnel Boring ◽  
Serial Chain ◽  
Smooth Movement ◽  
Cylindrical Array

This paper applies kinematic synthesis theory to obtain the dimensions of a constrained spatial serial chain for a valve mechanism that cleans and closes a soil conditioning port in a tunnel boring machine. The goal is a smooth movement that rotates a cylindrical array of studs into position and then translates it forward to clean and close the port. The movement of the valve is defined by six positions of the revolute-prismatic-revolute (RPR) serial chain. These six positions are used to compute the dimensions of the two spherical spherical (SS) dyads that constrain the RPR chain to obtain a one degree-of-freedom spatial mechanism. An example design of this valve mechanism is provided in detail.

scholarly journals Reconfiguration Analysis of an RRRRS Single-Loop Mechanism

Robotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 51
Author(s):  
Maurizio Ruggiu ◽  
Xianwen Kong
Keyword(s):  
Numerical Solutions ◽  
Motion Equation ◽  
Degree Of Freedom ◽  
Solid Model ◽  
Variable Degree ◽  
Single Loop ◽  
Motion Modes ◽  
The One ◽  
Classical Vector ◽  
First Time

The paper deals with the reconfiguration analysis of the single-loop variable degree-of-freedom (DOF) RRRRS mechanism composed of five links connected by four revolute (R) joints and one spherical (S) joint. The mechanism may show two modes of motion: one-DOF and two-DOF motion. In the paper, a classical vector procedure is used to obtain the quartic motion equation (QME) that allows one to inspect the nature of the motion. In general, the solutions of the QME provide the one-DOF motion of the mechanism except when all the coefficients of the equation vanish. In this case, the mechanism undergoes the two-DOF motion. The motion of the mechanism built according to two specific architectures was analyzed by the numerical solutions of the QME and with the help of the solid model of the mechanism. It is revealed for the first time that the perpendicular architecture has one 2-DOF motion and two 1-DOF motion modes.

Dimensional Synthesis of Planar Eight-Bar Linkages Based on a Parallel Robot With a Prismatic Base Joint

2013 ◽  
Author(s):  
Gim Song Soh ◽  
Fangtian Ying
Keyword(s):  
Rigid Body ◽  
Design Process ◽  
Parallel Robot ◽  
Degree Of Freedom ◽  
Dimensional Synthesis ◽  
End Effector ◽  
Prismatic Joint ◽  
Serial Chain ◽  
Different Types

This paper details the dimensional synthesis for the rigid body guidance of planar eight-bar linkages that could be driven by a prismatic joint at its base. We show how two RR cranks can be added to a planar parallel robot formed by a PRR and 3R serial chain to guide its end-effector through a set of five task poses. This procedure is useful for designers who require the choice of ground pivot locations. The results are eight different types of one-degree of freedom planar eight-bar linkages. We demonstrate the design process with the design of a multifunctional wheelchair that could transform its structure between a self-propelled wheelchair and a walking guide.

Fourier Methods for Kinematic Synthesis of Coupled Serial Chain Mechanisms

2005 ◽  
Vol 127 (2) ◽  
pp. 232-241 ◽  
Author(s):  
Xichun Nie ◽  
Venkat Krovi
Keyword(s):  
Low Cost ◽  
Synthesis Method ◽  
Path Following ◽  
Degree Of Freedom ◽  
Dimensional Synthesis ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Serial Chain ◽  
End Effectors ◽  
Serial Chains

Single degree-of-freedom coupled serial chain (SDCSC) mechanisms are a class of mechanisms that can be realized by coupling successive joint rotations of a serial chain linkage, by way of gears or cable-pulley drives. Such mechanisms combine the benefits of single degree-of-freedom design and control with the anthropomorphic workspace of serial chains. Our interest is in creating articulated manipulation-assistive aids based on the SDCSC configuration to work passively in cooperation with the human operator or to serve as a low-cost automation solution. However, as single-degree-of-freedom systems, such SDCSC-configuration manipulators need to be designed specific to a given task. In this paper, we investigate the development of a synthesis scheme, leveraging tools from Fourier analysis and optimization, to permit the end-effectors of such manipulators to closely approximate desired closed planar paths. In particular, we note that the forward kinematics equations take the form of a finite trigonometric series in terms of the input crank rotations. The proposed Fourier-based synthesis method exploits this special structure to achieve the combined number and dimensional synthesis of SDCSC-configuration manipulators for closed-loop planar path-following tasks. Representative examples illustrate the application of this method for tracing candidate square and rectangular paths. Emphasis is also placed on conversion of computational results into physically realizable mechanism designs.

Dimensional Synthesis of Planar Six-Bar Linkages by Mechanically Constrain a PRR Serial Chain

2012 ◽  
Author(s):  
Gim Song Soh ◽  
Fangtian Ying ◽  
J. Michael McCarthy
Keyword(s):  
Degree Of Freedom ◽  
Synthesis Process ◽  
Dimensional Synthesis ◽  
Serial Chain ◽  
Prismatic Joints

In this paper, we consider the problem of designing planar six-bar linkages which can be driven by prismatic joints at its base. We explore various ways on how two RR chains can be used to constraint a PRR planar serial chain such that the system yields one-degree of freedom yet passes through a set of five specified task positions. We formulate and solve the design equations as well as analyze the resulting planar six-bar linkage. We demonstrate the synthesis process with the design of the seat of a wheelchair such that it is able to transform itself to be used as a rehabilitation guide during rehabilitation.

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