Design of an Underactuated Finger Based on a Novel Nine-Bar Mechanism

2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Ming Cheng ◽  
Shaowei Fan ◽  
Dapeng Yang ◽  
Li Jiang
Keyword(s):  
Quantitative Analysis ◽  
Good Stability ◽  
Spring Stiffness ◽  
Prosthetic Hands ◽  
Grasp Stability ◽  
Global Workspace ◽  
Key Factor ◽  
The Stability ◽  
Underactuated Finger ◽  
Elastic Elements

Abstract Elastic elements are commonly adopted to realize underactuation in the design of human-friendly prosthetic hands. The stiffness of these elastic elements, which is a key factor affecting the grasp performance of the underactuated finger, has not well addressed when considering both the stability and adaptability. In this study, an adaptive anthropomorphic finger that adopted a novel nine-bar mechanism is proposed. This nine-bar mechanism is integrated through a coupled four-bar mechanism and an adaptive seven-bar mechanism. The developed finger based on the nine-bar mechanism is able to improve the grasp stability in the global workspace under an extremely small spring stiffness. A quantitative analysis of the grasp stability was carried out. Comparative experiments on the grasps using the finger with/without adaptability were also performed. The results validated that our finger has a good stability when grasping the objects of different sizes.

A parametric family of Massey-type methods: inference, prediction, and sensitivity

2020 ◽  
Vol 16 (3) ◽  
pp. 255-269
Author(s):  
Enrico Bozzo ◽  
Paolo Vidoni ◽  
Massimo Franceschet
Keyword(s):  
Quantitative Analysis ◽  
Control Theory ◽  
Dynamic Systems ◽  
Parametric Family ◽  
Time Varying ◽  
Multi Agent ◽  
Key Features ◽  
The Stability ◽  
Agent Coordination ◽  
Time Aware

AbstractWe study the stability of a time-aware version of the popular Massey method, previously introduced by Franceschet, M., E. Bozzo, and P. Vidoni. 2017. “The Temporalized Massey’s Method.” Journal of Quantitative Analysis in Sports 13: 37–48, for rating teams in sport competitions. To this end, we embed the temporal Massey method in the theory of time-varying averaging algorithms, which are dynamic systems mainly used in control theory for multi-agent coordination. We also introduce a parametric family of Massey-type methods and show that the original and time-aware Massey versions are, in some sense, particular instances of it. Finally, we discuss the key features of this general family of rating procedures, focusing on inferential and predictive issues and on sensitivity to upsets and modifications of the schedule.

Release Profile of a Model Protein Drug Depending on the Stability of Microspheres Based on Polyelectrolyte Complex

2007 ◽  
Vol 342-343 ◽  
pp. 505-508
Author(s):  
Sung Won Kim ◽  
Yun Sik Nam ◽  
Yeon Jin Min ◽  
Jong Ho Kim ◽  
Kwang Meyong Kim ◽  
...  
Keyword(s):  
Polyelectrolyte Complex ◽  
Coating Layer ◽  
Great Influence ◽  
Release Profile ◽  
Core Material ◽  
Glycol Chitosan ◽  
The Core ◽  
Key Factor ◽  
Model Protein ◽  
The Stability

Stability and disintegration of natural polyelectrolyte complex microspheres for protein drugs delivery have been extensively investigated because of their great influence on the drug release patterns. In this study, we tested stability of microspheres with alginate (Alg) core layered by either chitosan (Chi) or glycol chitosan (GChi) by examining release profiles of fluorophorelabeled bovine serum albumin (BSA) and lysozyme (Lys) from the microspheres. While GChi shell was disintegrated quickly, Chi-shell microspheres showed good stability in PBS. Disintegration of the coated layer induced the core material instable. The results indicated that while the charges of the shell material provided additional diffusion barrier against the protein release, the key factor to hold the proteins inside the microspheres was the integrity of the outer coating layer.

scholarly journals Sorption and Desorption Analysis of Nitrobenzene on Differently Functionalized Multiwalled Carbon Nanotubes and Implications on the Stability

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1426
Author(s):  
Zhanhua Ji ◽  
Dengyu Li
Keyword(s):  
Carbon Nanotubes ◽  
Underlying Mechanism ◽  
Multiwalled Carbon ◽  
Environmental Behaviors ◽  
Initial Concentration ◽  
Sorption Hysteresis ◽  
Key Factor ◽  
Functionalized Multiwalled Carbon Nanotubes ◽  
The Stability ◽  
Adsorption Desorption

The stability of carbon nanotubes (CNTs) suspension is a key factor in determining their transport, fate, and toxicity in an aquatic environment, which is significantly influenced by CNTs’ nature and water chemistry. Macromolecular dissolved organic matter (DOM) is reported to influence the stability of CNTs aggregation. However, little is known on small polar dissolved organic compound’s effects on CNTs aggregation. Nitrobenzene was selected to investigate its interaction with three different functionalized multiwalled CNTs (MWCNTs). Both the stability of CNTs aggregation and sorption hysteresis were affected by the initial concentration of nitrobenzene and the surface functionalization coverage of MWCNTs. At the initial concentration below 580 mg/L, the thermodynamic index of irreversibility (TII) and turbidity of CNTs suspension had the same tendency, indicating that the underlying mechanism is closely related. A conceptual adsorption–desorption model was proposed to further explain the relationship between the sorption hysteresis and stability of MWCNTs suspension under different initial concentrations of nitrobenzene. This provided data support to further clarify the environmental behaviors and risks of CNTs.

The stability analysis using Lyapunov exponents for high-DOF nonlinear vehicle plane motion

2021 ◽  
pp. 095440702110433
Author(s):  
Shuming Shi ◽  
Fanyu Meng ◽  
Minghui Bai ◽  
Nan Lin
Keyword(s):  
Stability Analysis ◽  
Quantitative Analysis ◽  
Lyapunov Exponents ◽  
Plane Motion ◽  
Vehicle Model ◽  
Motion Stability ◽  
Motion System ◽  
Nonlinear Vehicle Model ◽  
The Stability ◽  
Different Characteristics

The Lyapunov exponents method is an excellent approach for analyzing the vehicle plane motion stability, and the researchers demonstrated the effectiveness under 2-DOF vehicle model. However, whether the Lyapunov exponents approach can effectively reveal the characteristics of high-DOF nonlinear vehicle model is the key problem at present. In this paper, the Lyapunov exponents is applied to quantitatively analyze the stability of the nonlinear three and five degree of freedom vehicle plane motion system. The different characteristics between 2-DOF and high-DOF model are revealed and explained by using Lyapunov exponents. It illustrates the feasibility of using Lyapunov exponents to analyze the stability of high-DOF vehicle models, which supplements and perfects the existing quantitative analysis conclusion.

Design of Photoionization Detector Based on the Miniature Gas Chromatography

2013 ◽  
Vol 823 ◽  
pp. 291-295 ◽  
Author(s):  
Shou Chen Chai ◽  
Peng Yang ◽  
Cheng Jia Yang ◽  
Chun Li Cai ◽  
Na Yu
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Ionization Chamber ◽  
High Sensitivity ◽  
Fast Response ◽  
Low Detection Limit ◽  
Photoionization Detector ◽  
Key Factor ◽  
The Stability ◽  
Sensitivity Detection

In the space restricted airtight environment that people lives in, detecting harmful gas by miniature gas chromatography is the practical requirement at present, however, PIDs performance is key factor that restrict the application of miniature gas chromatography, the redesign of the detectors gas route in this paper aiming at improve detectors stability observably, and schemed out miniature PID with high sensitivity, low detection limit and fast response. The result of the experiment shows that the detection limit is 0.04ppm, the sensitivity is 101mv/ppm,the stability is 0.04×10-6/24h,meeting the project requirement. Keywords: photoionization detector; ionization chamber; sensitivity; detection limit;

scholarly journals ANÁLISE DA INTEGRIDADE E DA INSTABILIDADE DINÂMICA DE UM SISTEMA MECÂNICO SUJEITO A BIFURAÇÃO DO TIPO BUTTERFLY

2021 ◽  
Vol 12 (3) ◽  
pp. 14-22
Author(s):  
Michael Dowglas de Gois Silva ◽  
Fábio Roberto Chavarette ◽  
Milton Batista Ferreira Junior ◽  
Rodrigo Francisco Borges Lourenco
Keyword(s):  
Static Load ◽  
Structural Systems ◽  
Spring Stiffness ◽  
Bifurcation Diagrams ◽  
Model Uncertainties ◽  
Geometric Imperfections ◽  
Attraction Basin ◽  
Linear Buckling ◽  
Lower Load ◽  
The Stability

Slender structural systems susceptible to unstable buckling generally losestability at lower load levels than the linear buckling load of the perfect structure. This is mainly due to the geometric imperfections present in real structures. The objective of this work is to determine the integrity measures, together with the stability of the post-critical solutions of a mechanical system subject to unstable symmetrical buckling, Burtterfly-type bifurcation, using a discrete degree of freedom model. Uncertainties in the order of 10% will be considered in its deterministic parameters, to obtain lower and reliable limits for the project. The proposed uncertainty in the spring stiffness parameters does not change the type of bifurcation and the value of the critical load, only the value of the minimum post-critical of the bifurcation diagrams. The results showed the erosion of the attraction basin and the decrease of the factors of integrity, local and global, for the trivial solutions with the increase of the static load, for the investigated bifurcation.

Periodic Motions in an Autonomous System With a Discontinuous Vector Field

2020 ◽  
Author(s):  
Siyu Guo ◽  
Albert C. J. Luo
Keyword(s):  
Vector Field ◽  
Dynamical Systems ◽  
Numerical Simulations ◽  
Autonomous System ◽  
Parameter Study ◽  
Spring Stiffness ◽  
Algebraic Equations ◽  
Periodic Motions ◽  
Mapping Structures ◽  
The Stability

Abstract In this paper, periodic motions in an autonomous system with a discontinuous vector field are discussed. The periodic motions are obtained by constructing a set of algebraic equations based on motion mapping structures. The stability of periodic motions is investigated through eigenvalue analysis. The grazing bifurcations are presented by varying the spring stiffness. Once the grazing bifurcation occurs, periodic motions switches from the old motion to a new one. Numerical simulations are conducted for motion illustrations. The parameter study helps one understand autonomous discontinuous dynamical systems.

scholarly journals Degradation of Cardiac Troponin I in Serum Complicates Comparisons of Cardiac Troponin I Assays

1999 ◽  
Vol 45 (7) ◽  
pp. 1018-1025 ◽  
Author(s):  
Qinwei Shi ◽  
Mingfu Ling ◽  
Xiaochen Zhang ◽  
Minyuan Zhang ◽  
Lilly Kadijevic ◽  
...  
Keyword(s):  
Western Blot ◽  
Human Serum ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Cardiac Troponin I ◽  
Stable Region ◽  
Terminal Portion ◽  
Key Factor ◽  
The Stability ◽  
Serum Cardiac Troponin

Abstract Background: Up to a 20-fold variation in serum cardiac troponin I (cTnI) concentration may be observed for a given patient sample with different analytical methods. Because more limited variation is seen for control materials and for purified cTnI, we explored the possibility that cTnI was present in altered forms in serum. Methods: We used four recombinantly engineered cTnI fragments to study the regions of cTnI recognized by the Stratus®, Opus®, and ACCESS® immunoassays. The stability of these regions in serum was analyzed with Western blot. Results: The measurement of several control materials and different forms of purified cTnI using selected commercial assays demonstrated five- to ninefold variation. Both the Stratus and Opus assays recognized the N-terminal portion (NTP) of cTnI, whereas the ACCESS assay recognized the C-terminal portion (CTP) of cTnI. Incubation of recombinant cTnI in normal human serum produced a marked decrease in cTnI concentration as determined with the ACCESS, but not the Stratus, immunoassay. Western blot analysis of the same samples using cTnI NTP- and CTP-specific antibodies demonstrated preferential degradation of the CTP of cTnI. Conclusions: The availability of serum cTnI epitopes is markedly affected by the extent of ligand degradation. The N-terminal half of the cTnI molecule was found to be the most stable region in human serum. Differential degradation of cTnI is a key factor in assay-to-assay variation.

Chitosan-Stabilized Oil-in-Water Nanoemulsions

2022 ◽  
pp. 44-58
Author(s):  
Viktoria Milkova
Keyword(s):  
Physicochemical Characteristics ◽  
Biological Properties ◽  
Precise Control ◽  
Theoretical Approaches ◽  
Natural Polysaccharide ◽  
Oil In Water ◽  
Degree Of Acetylation ◽  
Key Factor ◽  
Potential Applications ◽  
The Stability

Chitosan is a natural polysaccharide and emulsifier that can ensure a significant emulsion stability at suitable pH, ionic strength, composition, concentration, or thermal processing. The evaluation of the electrokinetic properties is a key factor in investigation of the stability of the nanoemulsions with a view to their potential applications in bionanotechnology. Consequently, the precise control over the physicochemical characteristics of chitosan (degree of acetylation, DA and molecular weight, Mw) can provide a high stability and specific biological properties of the developed functional structures. The chapter is focused on the interpretation of the electrokinetic response from nanoemulsion stabilized by adsorption of chitosan (as a polyelectrolyte or uncharged polymer) by using appropriate theoretical approaches.

Object Manipulation Using Compliant Fingerpads: Modeling and Control

1993 ◽  
Vol 115 (4) ◽  
pp. 638-648 ◽  
Author(s):  
A. M. Annaswamy ◽  
D. Seto
Keyword(s):  
Adaptive Control ◽  
Feedback Linearization ◽  
Industrial Robots ◽  
Dynamic Interactions ◽  
Modeling And Control ◽  
Grasp Stability ◽  
Grasping And Manipulation ◽  
End Effectors ◽  
Geometric Techniques ◽  
The Stability

Current industrial robots are often required to perform tasks requiring mechanical interactions with their environment. For tasks that require grasping and manipulation of unknown objects, it is crucial for the robot end-effector to be compliant to increase grasp stability and manipulability. The dynamic interactions that occur between such compliant end-effectors and deformable objects that are being manipulated can be described by a class of nonlinear systems. In this paper, we determine algorithms for grasping and manipulation of these objects by using adaptive feedback techniques. Methods for control and adaptive control of the underlying nonlinear system are described. It is shown that although standard geometric techniques for exact feedback linearization techniques are inadequate, yet globally stable adaptive control algorithms can be determined by making use of the stability characteristics of the underlying nonlinear dynamics.

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