Controlling the Rotational DOF of Laminar Jamming Structures With End Clamping Mechanism

2020 ◽  
Author(s):  
Emily A. Allen ◽  
John P. Swensen
Keyword(s):  
Pressure Gradient ◽  
Variable Stiffness ◽  
Degree Of Freedom ◽  
Rotational Degree ◽  
Beam Structure ◽  
Preliminary Results ◽  
High Stiffness ◽  
Additional Mode ◽  
Translational Degree ◽  
Rotational Freedom

Abstract Variable stiffness structures lie at the nexus of soft robots and traditional robots as they enable the execution of both high-force tasks and delicate manipulations. Laminar jamming structures, which consist of thin flexible sheets encased in a sealed chamber, can alternate between a rigid state when a vacuum is applied and a flexible state when the layers are allowed to slide in the absence of a pressure gradient. In this work, an additional mode of controllability is added by clamping and unclamping the ends of a simple laminar jamming beam structure. Previous works have focused on the translational degree of freedom that may be controlled via vacuum pressure; here we introduce a rotational degree of freedom that may be independently controlled with a clamping mechanism. Preliminary results demonstrate the ability to switch between three states: high stiffness (under vacuum), translational freedom (with clamped ends, no vacuum), and rotational freedom (with ends free to slide, no vacuum).

Design and Evaluation of a Passive Ankle Prosthesis With Rotational Power Generation by a Compliant Coupling Between Leg Deflection and Ankle Rotation

2014 ◽  
Author(s):  
Jacob J. Rice ◽  
Joseph M. Schimmels
Keyword(s):  
Degrees Of Freedom ◽  
Gait Cycle ◽  
The Body ◽  
Degree Of Freedom ◽  
Rotational Degree ◽  
Kinematic Data ◽  
Active Behavior ◽  
Ankle Prosthesis ◽  
Compression Spring ◽  
Translational Degree

This paper presents the design and simulation results of a passive prosthetic ankle prosthesis that has mechanical behavior similar to a natural ankle. The presented design achieves active behavior with powered push-off to propel the body forward. The design contains a conventional compression spring network that allows coupling between two degrees of freedom. There is a translational degree of freedom along the leg and a rotational degree of freedom about the ankle joint. During a standard gait cycle, potential energy from the person’s weight is stored in the spring network from deflection along the leg. The energy is released by the spring network as rotation of the foot. With this design, capping the allowable leg deflection at 15 millimeters produces 45% of the rotational work that a natural ankle will produce. This is based on simulation using published average kinetic and kinematic data from gait analyses.

Anomalous metallic-like transport of Co–Pd ferromagnetic nanoparticles cross-linked with π-conjugated molecules having a rotational degree of freedom

2014 ◽  
Vol 16 (1) ◽  
pp. 288-296 ◽  
Author(s):  
Yoshikazu Ito ◽  
Kazuyuki Takai ◽  
Akira Miyazaki ◽  
Vajiravelu Sivamurugan ◽  
Manabu Kiguchi ◽  
...  
Keyword(s):  
Degree Of Freedom ◽  
Ferromagnetic Nanoparticles ◽  
Rotational Degree ◽  
Conjugated Molecules

The thermodynamics of intracrystalline sorption I. Models of the sorbed state

1956 ◽  
Vol 234 (1196) ◽  
pp. 24-34 ◽  
Keyword(s):  
Mobile Phase ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Translational Degree ◽  
Sorbate Concentration ◽  
The Ideal

Three basic models of the intracrystalline sorbed state are discussed: a localized phase, a mobile phase possessing two translational degrees of freedom, and a mobile phase with one translational degree of freedom. The isotherm and entropy of each of these models have been investigated for the ideal phase, and where possible the influence of sorbate-sorbate interactions has been considered. Expressions for the molal and differential entropies of each model are given as a function of sorbate concentration. The method of comparing theoretical isotherms and entropies with experimental observations is outlined.

scholarly journals Design and Modeling of Parallel Two-degree-of-freedom Variable Stiffness Actuator

2020 ◽  
Vol 461 ◽  
pp. 012019
Author(s):  
Shangkui Yang ◽  
Peng Chen ◽  
Yongzhan Cao ◽  
Shuyun Zhu ◽  
Zhuang Ge ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Degree Of Freedom ◽  
Variable Stiffness Actuator ◽  
Two Degree Of Freedom

The thermodynamics of intracrystalline sorption II. Argon in chabazite

1956 ◽  
Vol 234 (1196) ◽  
pp. 35-45 ◽  
Keyword(s):  
Experimental Data ◽  
Mobile Phase ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Translational Degree ◽  
Sorbed Phase

The experimentally observed isotherms and entropies of the intracrystalline sorbed phase of argon in natural and calcium chabazites are compared with those predicted by models. For sorbate concentrations between approximately θ = 0.1 and 0.7, the experimental data are incompatible with the properties of a localized phase but are in agreement with those of a mobile phase. It is demonstrated that it is impossible for the argon to possess two degrees of translational freedom and that it is best described as having one translational degree of freedom and two vibrational degrees of freedom each with a frequency of 1 x 10 12 to 2 x 10 12 s -1 . The examination of the entropy of the system also shows that at concentrations greater than θ = 0.7 the mobile concept breaks down and it is probable that the translational degree of freedom passes to a vibration due to the mutual caging action of sorbate molecules, so that the phase becomes a system of oscillators.

scholarly journals On a Two-DoF Parallel and Orthogonal Variable-Stiffness Actuator: An Innovative Kinematic Architecture

Robotics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 39 ◽  
Author(s):  
Matteo Malosio ◽  
Francesco Corbetta ◽  
Francisco Ramìrez Reyes ◽  
Hermes Giberti ◽  
Giovanni Legnani ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Degree Of Freedom ◽  
Variable Stiffness Actuator ◽  
Variable Stiffness Actuators

Variable-Stiffness Actuators are continuously increasing in importance due to their characteristics that can be beneficial in various applications. It is undisputed that several one-degree-of-freedom (DoF) solutions have been developed thus far. The aim of this work is to introduce an original two-DoF planar variable-stiffness mechanism, characterized by an orthogonal arrangement of the actuation units to favor the isotropy. This device combines the concepts forming the basis of a one-DoF agonist-antagonist variable-stiffness mechanism and the rigid planar parallel and orthogonal kinematic one. In this paper, the kinematics and the operation principles are set out in detail, together with the analysis of the mechanism stiffness.

A Parameter to Quantify Molecular Quasilinearity

1976 ◽  
Vol 31 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Koichi Yamada ◽  
Manfred Winnewisser
Keyword(s):  
Physical Interpretation ◽  
Separation Of Variables ◽  
Degree Of Freedom ◽  
Rotational Degree ◽  
Vibrational Degree ◽  
Model Calculations ◽  
Linear Configuration ◽  
Oppenheimer Approximation ◽  
Linear Molecules ◽  
Simple Parameter

Abstract A simple parameter is proposed for expressing the quasilinearity of molecules in a quantitative way. The parameter γ0 is defined on the basis of a discussion of the separation of variables in the Born-Oppenheimer approximation. The parameter γ0 assumes the value +1 for bent molecules and -1 for linear molecules. The range from -1 to +1 traces the transition of a vibrational degree of freedom in the linear configuration of a polyatomic molecule into a rotational degree of freedom in the bent configuration. The sequence of molecules along this parameter is shown and model calculations are carried out to further illustrate the physical interpretation of the parameter.

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