The relationship between the knee adduction torque and medial contact force during gait

2006 ◽  
Vol 39 ◽  
pp. S70 ◽  
Author(s):  
D. Zhao ◽  
S.A. Banks ◽  
K. Mitchell ◽  
D. D'Lima ◽  
C. Colwell ◽  
...  
Keyword(s):  
Contact Force ◽  
The Relationship

Stability Analysis of Planar Grasp with 2D-Virtual Spring Model

1999 ◽  
Vol 11 (4) ◽  
pp. 274-282 ◽  
Author(s):  
Takayoshi Yamada ◽  
◽  
Sushanta Kumar Saha ◽  
Nobuharu Mimura ◽  
Yasuyuki Funahashi ◽  
...  
Keyword(s):  
Contact Force ◽  
External Disturbance ◽  
Rolling Contact ◽  
Initial Contact ◽  
Spring Model ◽  
Spring Stiffness ◽  
Grasp Stability ◽  
Stiffness Matrices ◽  
The Relationship ◽  
Special Case

We analyze stability of planar grasp using a 2D virtual spring model. A 2D virtual spring model is widely used to explore frictionless grasp, but the direction of contact force has not been studied for a grasped object displaced by external disturbance. Finger displacement is restricted to the normal at initial contact. We introduce a 2D spring model for a frictionless case. The direction of contact force is explicitly formulated. Using potential energy, we analyze stability of frictionless grasp and show that the 1D-spring model is a special case of our proposed 2D-spring model. Frictional grasp stability is also studied using rolling contact. Numerical examples of 2-fingered grasp demonstrate the effects of parameters such as spring stiffness and contact force. It is shown that an optimum force exists for stabilizing frictionless grasp. It is proved that friction enhances grasp stability from the relationship between frictionless and frictional stiffness matrices. Stiffness conditions for stabilizing 3-fingered grasp is clarified.

DEM study to determine the relationship between particle velocity fluctuations and contact force disappearance

2017 ◽  
Vol 313 ◽  
pp. 112-121 ◽  
Author(s):  
Yong Zeng ◽  
Fuguo Jia ◽  
Yaxiong Zhang ◽  
Xiangyi Meng ◽  
Yanlong Han ◽  
...  
Keyword(s):  
Contact Force ◽  
Particle Velocity ◽  
Velocity Fluctuations ◽  
The Relationship

Analysis and Visualization of the Contact Force Solution Space for Multi-Limbed Mobile Robots With Three Feet Contact

2003 ◽  
Author(s):  
Dennis W. Hong ◽  
Raymond J. Cipra
Keyword(s):  
Contact Force ◽  
Dimensional Space ◽  
Contact Point ◽  
Solution Process ◽  
Solution Space ◽  
Contact Forces ◽  
Static Equilibrium ◽  
Equilibrium Equations ◽  
Force Components ◽  
The Relationship

A new analytical method for determining, describing, and visualizing the solution space for the contact force distribution of multi-limbed robots with three feet in contact with the environment in three-dimensional space is presented. The foot contact forces are first resolved into strategically defined foot contact force components to decouple them for simplifying the solution process, and then the static equilibrium equations are applied to find certain contact force components and the relationship between the others. Using the friction cone equation at each foot contact point and the known contact force components, the problem is transformed into a geometrical one to find the ranges of contact forces and the relationship between them that satisfy the friction constraint. Using geometric properties of the friction cones and by simple manipulation of their conic sections, the whole solution space which satisfies the static equilibrium and friction constraints at each contact point can be found. Two representation schemes, the “force space graph” and the “solution volume representation,” are developed for describing and visualizing the solution space which gives an intuitive visual map of how well the solution space is formed for the given conditions of the system.

Model Test of Integrated Floating Transport Technology of Offshore Wind Turbines With Composite Bucket Foundation

2018 ◽  
Author(s):  
Hongyan Ding ◽  
Lingqian Meng ◽  
Puyang Zhang ◽  
Conghuan Le
Keyword(s):  
Wind Turbine ◽  
Contact Force ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Bucket Foundation ◽  
Offshore Wind Turbines ◽  
Continuous Innovation ◽  
One Step ◽  
The One ◽  
The Relationship

With continuous innovation and development of the wind power technology, the offshore wind turbine is rapidly developing. However, it also has difficulties in construction at sea and other shortcomings. One-step installation technique of the composite bucket foundation (CBF) provides a new way to solve the difficulties in the construction of offshore wind turbine at sea. And the integrated floating transport technique of the offshore CBF is the key link in the one-step installation technique. In this paper, by controlling three factors, such as draft, wave height and speed, the contact force between the vessel and CBF in the integrated floating transportation process is studied with experimental method. The relationship and the effect between the three factors and the contact force is analyzed. The experimental results are collected and analyzed to verify the safety of the integrated floating transportation of offshore CBF.

Theoretical modeling and numerical simulation of dynamic contact characteristics of a spherical pump with variable friction coefficient

2021 ◽  
pp. 135065012110162
Author(s):  
Dong Guan ◽  
Li Jing ◽  
Xue Han ◽  
Lihui Wang ◽  
Junjie Gong
Keyword(s):  
Friction Coefficient ◽  
Contact Force ◽  
Structural Parameters ◽  
Dynamic Contact ◽  
Cylinder Block ◽  
Normal Contact ◽  
Variable Friction ◽  
Resistance Performance ◽  
The Relationship ◽  
Maximum Contact

In this paper, the dynamic contact characteristics between a piston system and a cylinder block in a spherical pump are studied theoretically and numerically. The theoretical contact model between a piston and a cylinder is established based on its structural and operational properties, to obtain the maximum contact force quantitatively. The effects of different structural parameters and working pressures on the contact force are analyzed and discussed. The relationship between friction coefficient and rotation speed is presented. The contact pairs are modeled numerically using the finite-element method and augmented Lagrange algorithm to obtain both the tangential and normal contact characteristics. Both static and dynamic contact characteristics of the piston are analyzed and discussed. These proposed studies can provide practical suggestions on improving the wear resistance performance and durability of the spherical pump.

A Low Contact Force Polishing System for Micro Molds that Utilizes 2-Dimensional Low Frequency Vibrations (2DLFV) with Piezoelectric Actuators (PZT) and a Mechanical Transformer Mechanism

2013 ◽  
Vol 7 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Sze Keat Chee ◽  
◽  
Hirofumi Suzuki ◽  
Junchi Uehara ◽  
Takeshi Yano ◽  
...  
Keyword(s):  
Contact Force ◽  
Dwell Time ◽  
Low Frequency ◽  
Piezoelectric Actuators ◽  
Channel Structure ◽  
Micro Channel ◽  
Metal Structures ◽  
Time Control ◽  
Polishing Tool ◽  
The Relationship

This study proposes and develops a novel polishing system for micro molds which need high precision polishing, high aspect ratio of micro channel structure, or further miniaturization for micro channel structure. The proposed system has been named a “low contact force polishing system for micro mold utilizing 2-dimensional low frequency vibrations (2DLFV) with piezoelectric actuators (PZTs) and a mechanical transformer mechanism.” The system consists of 2DLFV with PZTs incorporated into the mechanical transformer structure, a low contact force loader, and a polishing tool. The shape of the polishing tool is flexible and can be changed depending on the complicatedness of the shape of the work. Several experiments are conducted to evaluate the performance of the polishing system. The evaluation reveals that a convex removal footprint can be easily achieved with the polishing system. The fact that the relationship between the removal depth and the polishing time suit Preston’s law well shows a stable polishing process is realized with the system. The polishing performances remains the same even if the shape of the polishing tool is changed. This indicates that the system can use polishing tools of a wide selection of shapes, which allows the system to polish a large variety of materials and most of the complicated shapes of metal structures, achieving a dramatic reduction in surface roughness. The plano raster polishing results also show the system to be well suited to the dwell time control polishing because the results show the removal footprint to be proportional to the dwell time and the defined raster path. All in all, the system is a versatile polishing system capable of achieving the intended objectives.

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