On mobile assemblies of Bennett linkages

2008 ◽  
Vol 464 (2093) ◽  
pp. 1275-1293 ◽  
Author(s):  
Y Chen ◽  
Z You
Keyword(s):  
Deployable Structures ◽  
Single Degree ◽  
Deployable Structure ◽  
The One ◽  
Cylindrical Profile

This paper deals with deployable structures formed by interconnected Bennett linkages. A total of eight cases that allow mobile assemblies of Bennett linkages being built have been found by considering the links that may contain sections with negative length. Among the eight assemblies, four are distinct ones, including the one that we reported previously, and the remaining can be obtained by modifying the four cases. All these assemblies consist of a grid of nested Bennett linkages. The layout of the assemblies can be repeated to form a large deployable structure. When the Bennett linkages are equilateral, the assemblies expand to form arches. For a non-equilateral case, the assemblies deploy into a helical shape with a cylindrical profile. They are geometrically overconstrained with a single degree of mobility. The newly found assemblies provide more choices in the design of deployable structures.

Mobile assemblies based on the Bennett linkage

2005 ◽  
Vol 461 (2056) ◽  
pp. 1229-1245 ◽  
Author(s):  
Y Chen ◽  
Z You
Keyword(s):  
Single Layer ◽  
Degree Of Freedom ◽  
Deployable Structures ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Cylindrical Profile

This paper presents a method of building large mobile assemblies using the Bennett linkage. The method is based on a basic single-layer layout consisting of overlapping 4 R loops, each of which is a Bennett linkage. The assemblies created have a single degree of freedom, and are overconstrained and scaleable, allowing unlimited extension by repetition. In general, they deploy into a circular or non-circular cylindrical profile. The joints of the assemblies move spirally on the surface during deployment. Under some particular geometrical conditions, the profiles of the assemblies can become arch-like or flat. Moreover, the single-layer assemblies can be extended to form multi-layer mechanisms, even mobile masts. The paper shows the great versatility of the Bennett linkage and demonstrates that the century-old invention can play an important role in the construction of deployable structures.

Kinematic Drift of Single-Axis Gyroscopes

1958 ◽  
Vol 25 (3) ◽  
pp. 357-360
Author(s):  
R. H. Cannon
Keyword(s):  
Experimental Verification ◽  
Spatial Orientation ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Momentum Vector ◽  
Single Degree ◽  
The One ◽  
Platform Motions

Abstract A gyroscope can incur steady drift by kinematically rectifying angular vibrations of the platform on which it is mounted. The phenomenon, for an unrestrained single-degree-of-freedom gyro, results from oscillatory precession of the gyro momentum vector from its nominal spatial orientation, so that it senses platform motions about axes other than the one it is controlling. The magnitude of the drift can be accurately predicted and the vibration climate of the platform restricted accordingly. Quantitative experimental verification is presented.

scholarly journals Symmetric waterbomb origami

2016 ◽  
Vol 472 (2190) ◽  
pp. 20150846 ◽  
Author(s):  
Yan Chen ◽  
Huijuan Feng ◽  
Jiayao Ma ◽  
Rui Peng ◽  
Zhong You
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Solar Panels ◽  
Deployable Structures ◽  
Single Degree Of Freedom ◽  
Folding Process ◽  
Multiple Degrees Of Freedom ◽  
Single Degree ◽  
Flat Roofs ◽  
Additional Constraints

The traditional waterbomb origami, produced from a pattern consisting of a series of vertices where six creases meet, is one of the most widely used origami patterns. From a rigid origami viewpoint, it generally has multiple degrees of freedom, but when the pattern is folded symmetrically, the mobility reduces to one. This paper presents a thorough kinematic investigation on symmetric folding of the waterbomb pattern. It has been found that the pattern can have two folding paths under certain circumstance. Moreover, the pattern can be used to fold thick panels. Not only do the additional constraints imposed to fold the thick panels lead to single degree of freedom folding, but the folding process is also kinematically equivalent to the origami of zero-thickness sheets. The findings pave the way for the pattern being readily used to fold deployable structures ranging from flat roofs to large solar panels.

Geometric Analysis of a Modular, Deployable and Reusable Structure

2019 ◽  
Vol 805 ◽  
pp. 155-160 ◽  
Author(s):  
F. Ama Gonzalo ◽  
Mariano Molina ◽  
Covadonga Lorenzo ◽  
M.I. Castilla ◽  
Pulido D. Gomez ◽  
...  
Keyword(s):  
Geometric Analysis ◽  
Maximum Length ◽  
Structural Behavior ◽  
Deployable Structures ◽  
Deployable Structure ◽  
Wide Range ◽  
Post Tensioning ◽  
Expanded Form

The use of deployable structures has a wide range of applications nowadays. They can be transformed from a closed compact configuration to a predetermined expanded form, in which they are stable and can carry loads. This article describes a sort of deployable structure that has been patented by researchers of two Spanish institutions: San Pablo CEU University and Eduardo Torroja Institute. Geometric aspects are key to accomplish an efficient folding and unfolding procedure along with an optimum structural behavior when the structure is deployed. Tensioned cables are essential in these structures. The main goal is to make the cable acquire its maximum length when the structure is fully deployed. This will avoid complex operations of post-tensioning in order to make the cable perform its function.

scholarly journals Non-Linear Vibration Isolators with Unknown Excitation and Unmodelled Dynamics: Sliding Mode Active Control

2019 ◽  
Vol 9 (17) ◽  
pp. 3567 ◽  
Author(s):  
Zhang ◽  
Hu ◽  
Liu ◽  
Ouyang ◽  
Zhang
Keyword(s):  
Sliding Mode ◽  
Control Methods ◽  
Practical Application ◽  
Linear Vibration ◽  
Single Degree Of Freedom ◽  
Vibration Isolators ◽  
Single Degree ◽  
Non Linear ◽  
The One ◽  
Twisting Algorithm

For a class of single-degree-of-freedom non-linear passive vibration isolators with unknown excitation and unmodelled dynamics, two sliding mode control methods—a conventional one and the other using a super-twisting algorithm—were proposed to complement and improve the performances and the robustness of the passive isolators. The proposed control methods only require the estimation of the loading and measured velocities of the isolators. Numerical simulations for a non-linear isolator with quasi-zero stiffness demonstrated that both methods were effective and easy to implement, and the one using a super-twisting algorithm was more promising from the perspective of practical application.

Deployable Prismatic Structures With Origami Patterns

2014 ◽  
Author(s):  
Sicong Liu ◽  
Weilin Lv ◽  
Yan Chen ◽  
Guoxing Lu
Keyword(s):  
Design Method ◽  
Kinematic Model ◽  
The Other ◽  
Dihedral Angles ◽  
Geometric Condition ◽  
Compatibility Conditions ◽  
Deployable Structures ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Geometric Compatibility

In order to find the general condition of the rigid origami pattern for the deployable prismatic structures, the kinematic model is proposed based on the mobile assemblies of spherical 4R linkages. The kinematic and geometric compatibility conditions of the mobile assemblies are derived. Two groups of 2n-side deployable prismatic structures are obtained. When n=2, one of them is with kite-shape intersection, while the other is with parallelgram. The variations of the unit are discussed. The straight and curvy multilayer prisms are built by changing the dihedral angles between the intersecting planes. The general design method for the 2n-side multilayer deployable prismatic structures is proposed with the geometric condition of the origami patterns. All the deployable structures constructed with this method can be deployed and folded along the central axis of the prisms with single degree of freedom, which makes the structures have wide engineering applications.

Single-Degree-of-Freedom Rigidly Foldable Origami Flashers

2015 ◽  
Author(s):  
Robert J. Lang ◽  
Spencer Magleby ◽  
Larry Howell
Keyword(s):  
Degree Of Freedom ◽  
Deployable Structures ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Revolute Joints

We present the design for a family of deployable structures based on the origami flasher that are rigidly foldable, i.e., foldable with revolute joints at the hinges and planar rigid faces, and that exhibit a single degree of freedom in their motion. These structures may be used to realize highly compact deployable mechanisms.

The influence of joint eccentricity on the foldability of four deployable structure systems

2021 ◽  
pp. 095605992110484
Author(s):  
Adolfo Pérez-Egea ◽  
Pedro García Martínez ◽  
Martino Peña Fernández-Serrano ◽  
Pedro Miguel Jiménez Vicario ◽  
Manuel Alejandro Ródenas-López
Keyword(s):  
Tube Bundle ◽  
Deployable Structures ◽  
Deployable Structure ◽  
Constituent Elements

The study of deployable structures has been carried out traditionally by simplifying their constituent elements—joints and rods—to ideal entities. However, in this paper the dimensional thickness of these elements is taken into account, in order to evaluate their incidence on the foldability of four deployable structure systems. We have examined the eccentricity that occurs specifically at the joints themselves. Our study ultimately characterizes the incidence of this factor by defining noteworthy parameters common to both tube bundle and scissor systems, enabling us to establish a comparison and draw relevant conclusions.

Theoretical Analysis and Experimental Investigation on Buckling of FASTMast Deployable Structures

2015 ◽  
Vol 15 (05) ◽  
pp. 1450075 ◽  
Author(s):  
Yulong Jin ◽  
Tao Liu ◽  
Rongxin Lyu ◽  
Bin Ji ◽  
Qifeng Cui
Keyword(s):  
Theoretical Analysis ◽  
Solar Array ◽  
Joint Movement ◽  
Deployable Structures ◽  
Buckling Mode ◽  
Cross Sectional ◽  
Euler Buckling ◽  
Deployable Structure ◽  
Research Findings ◽  
Stiffness Characteristics

FASTMast (Folding Articulated Square Truss Mast) deployable structure is the main bracing structure for the flexible solar array of the international space stations. This study investigates the buckling of FASTMast deployable structures. To this end, the buckling modes and the stiffness characteristics of this structure using the flex batten as an elastic bearing member were theoretically analyzed. The analytical results show that (1) the buckling mode of a FASTMast deployable structure is similar to the elbow joint movement failure when the stiffness of the flex batten is below a critical stiffness value. Once this critical stiffness is reached, the buckling mode takes on the form of Euler buckling. (2) The stiffness of the flex batten is proportional to its cross-sectional second moment of area. Furthermore, an experimental study was carried out to validate the accuracy of the theoretical analysis. The results from experimental work agree fairly well with those from theoretical analysis. The research findings herein are expected to be useful for future studies on similar structures.

Experimental Development of Self-Deployable Structures

1998 ◽  
Vol 13 (3) ◽  
pp. 157-169
Author(s):  
Depankar Neogi ◽  
Craig Douglas ◽  
David R. Smith
Keyword(s):  
Research Effort ◽  
Research Work ◽  
Building Blocks ◽  
The Self ◽  
Structural Element ◽  
Deployable Structures ◽  
Experimental Development ◽  
Deployable Structure ◽  
New Family ◽  
Standing Structure

Deployable space structures are prefabricated structures which can be transformed from a closed, compact configuration to a predetermined expanded form in which they are stable and can bear loads. The present research effort investigates a new family of deployable structures, called self-deployable structures. Unlike other deployable structures, which have rigid members and moving joints, the self-deployable members are flexible while the connecting joints are rigid. The joints store the predefined geometry of the deployed structure in the collapsed state. The self-deployable structure is stress-free in both deployed and collapsed configurations and results in a self-standing structure which acquires its structural properties after a chemical reaction. Reliability of deployment is one of the most important features of the self-deployable structure, since it does not rely on mechanisms that can lock during deployment. The unit building block of these structures is the self-deployable structural element. Several of these elements can be linked to generate more complex building blocks such as a triangular or tetrahedral structures. Different self-deployable structural element and self-deployable structure concepts are investigated in the present research work, and the performance of triangular and tetrahedral prototype structures are experimentally explored.

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