Robotic Assembly Using Vibrations

2006 ◽  
Vol 113 ◽  
pp. 301-306
Author(s):  
Bronius Bakšys ◽  
Nomeda Puodziuniene
Keyword(s):  
Friction Coefficient ◽  
Dynamic Model ◽  
Friction Force ◽  
Equilibrium Position ◽  
Dry Friction ◽  
Dynamic Equilibrium ◽  
The Body ◽  
Robotic Assembly ◽  
Time Interval ◽  
Passive Compliance

On the basis of the dynamic model of vibratory alignment the main features of the vibrational assembly process are investigated. The regularities of non−impact alignment, when an immovable part is excited in two perpendicular directions, are defined. It is revealed that during the vibrational alignment the movable part can move from static till dynamic equilibrium position. The distance between these two positions defines allowable error of mutual positioning of the parts subject to the assembly, when the unhindered parts insertion is still possible. On the basis of the dynamic model of vibratory displacement the regularities of a body displacement under controlled dry friction force at a particular time interval is examined. If elastic vibrations are excited, dry friction coefficient decreases and smaller friction force acts against the body displacement. Stoppage of these vibrations causes a steep increase of friction coefficient. When the body moves from static to dynamic equilibrium position on the inclined plane the vibratory displacement is governed by the transient regimes of motion. Assembly robots equipped with passive compliance vibratory end-effectors allow one to compensate considerably bigger deviations in part’s interposition without using sensors and feedback systems. Therefore usage of vibratory devices with passive compliance allows one to significantly reduce the expenses of robotic assembly.

Tribology research of the turned zirconium-dioxide ceramics

2012 ◽  
Vol 3 (3) ◽  
pp. 181-190
Author(s):  
G. Fledrich ◽  
R. Keresztes ◽  
L. Zsidai
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Dry Friction ◽  
Zirconium Dioxide ◽  
Steel Specimen ◽  
Friction Condition ◽  
Normal Direction ◽  
Basic Material ◽  
Series Production ◽  
Ceramic Specimen

The zirconium dioxide as basic material is suitable to machine by tool with regular edge derivingfrom lower ceramic hardness and from other characteristics so in case of piece production or small – andmedium series production, at quick prototype production can become potential material alike. The aims tocompare the arising frictional characteristics in case of dry friction condition in case of ceramic – steelsurface pairs machined with different sets. We have developed for an equipment to carry out tribologicaltests. During the test we pressure the steel counter face with determined normal direction force thecasing surface of the rotating ceramic specimen and in the meantime we measure the value of the frictionforce with force meter cell. We have calculated the friction coefficient characterizing the system from thenormal direction force and the friction force as well as we measured the wear of the steel specimen andits deformation.

Dry Friction Effect on the Work of Viscous Torsion Damper

2016 ◽  
Vol 817 ◽  
pp. 13-18
Author(s):  
Celina Jagiełowicz-Ryznar
Keyword(s):  
Friction Coefficient ◽  
Free Vibration ◽  
Friction Force ◽  
Vibration Frequency ◽  
Forced Vibration ◽  
Dry Friction ◽  
Viscous Damper ◽  
The Real ◽  
Free Vibration Frequency ◽  
Marine Engines

The results of crankshaft forced vibration calculations, including the dry friction force which can be formed in the viscous damper bearing sliding, were presented. This problem concerns the big dampers used in the marine engines. The friction force influence is presented using the function {sign}. Low values of friction coefficient, corresponding to the conditions similar to the real ones, were assumed. In the range of tested value, it was found that the vibration increases linearly, and system free vibration frequency doesn’t change practically.

Dynamic Model for Free-Standing Fuel Racks Under Seismic Excitation Considering Planar and Nonslide Rocking Motion

2017 ◽  
Vol 12 (6) ◽  
Author(s):  
Kazuya Sakamoto ◽  
Ryosuke Kan ◽  
Akihiro Takai ◽  
Shigehiko Kaneko
Keyword(s):  
Friction Coefficient ◽  
Dynamic Model ◽  
Friction Force ◽  
Spent Nuclear Fuel ◽  
Inertial Force ◽  
Seismic Excitation ◽  
Free Standing ◽  
Fluid Force ◽  
Translational Movement ◽  
Rocking Motion

A free-standing (FS) rack is a type of a spent nuclear fuel rack, which is just placed on a floor of a pool. For this characteristic, seismic loads can be reduced by fluid force and friction force, but a collision between a rack and another rack or a wall must be avoided. Therefore, it is necessary for designing an FS rack to figure out how it moves under seismic excitation. In this research, a dynamic model of an FS rack is developed considering seismic inertial force, friction force, and fluid force. This model consists of two submodels: a translation model, which simulates planar translational and rotational motion, and a rocking model, which simulates nonslide rocking motion. First, simulations with sinusoidal inertial force were conducted, changing values of a friction coefficient. Next, to validate this dynamic model, a miniature experiment was conducted. Finally, the model is applied to a real-size FS rack and actually observed seismic acceleration. It is found that translational movement of a rack varies depending on the value of friction coefficient in the simulation with sinusoidal and actual acceleration. Also, simulation results are similar to the experimental results in the aspects of translational and rocking motion provided friction coefficient is selected properly. Through this research, the knowledge is acquired that friction force plays a significant role in a motion of FS rack so that estimating and controlling a friction coefficient is important in designing an FS rack.

scholarly journals CAN THE FRICTION FORCE BE THE DRIVING FORCE?

2020 ◽  
Vol 71 (3) ◽  
pp. 111-117
Author(s):  
L.G. Kassenov ◽  
◽  
B.H. Zhanbusinova ◽  
S.S. Sagintayev ◽  
◽  
...  
Keyword(s):  
Friction Force ◽  
Dry Friction ◽  
Driving Force ◽  
Materials Science ◽  
The Body ◽  
Friction Forces ◽  
Maximum Value ◽  
Physical Materials ◽  
Two Bodies

Friction is one of the types of interaction between bodies. It occurs when two bodies touch. The forces acting between the surfaces of contacting solids are called dry friction forces. They are always directed tangentially to the touching surfaces and are divided into the forces of friction at rest, sliding and rolling. The friction forces depend on many factors that accompany the movement of bodies in the presence of friction. In this regard, the description of friction forces is possible only with the help of empirically found approximate laws, which are often quite rough. The rest friction force is a variable value, it can change from zero to a certain maximum value. By applying a force to the body that exceeds the maximum resting friction force, we will move the body from its place, and it will begin to move. The article considers examples of motion in which the friction force can be mistakenly interpreted as a driving force. The nature of the forces of friction at rest and rolling is considered from the perspective of modern physical materials science.

Construction of Dynamic Model of Planar and Rocking Motion for Free Standing Spent Fuel Rack

2017 ◽  
Author(s):  
Kazuya Sakamoto ◽  
Ryosuke Kan ◽  
Akihiro Takai ◽  
Shigehiko Kaneko
Keyword(s):  
Friction Coefficient ◽  
Dynamic Model ◽  
Friction Force ◽  
Spent Nuclear Fuel ◽  
Inertial Force ◽  
Spent Fuel ◽  
Free Standing ◽  
Fluid Force ◽  
Rocking Motion ◽  
Spent Fuel Pool

Spent nuclear fuel is settled in racks and stored in spent fuel pool. A free standing rack (FS rack) is a type of a spent fuel rack, which is not fixed to walls unlike conventional ones. For this characteristic, movement of an FS rack during an earthquake can be reduced by fluid force and friction force. However, collision between a rack and another rack or a wall must be avoided. Therefore, it is necessary for designing an FS rack to figure out how it moves under seismic excitation. In this research, a dynamic model of FS racks is constructed considering seismic inertial force, friction force and fluid force. This model consists of two sub-models: translation model, which simulates planar translational and rotational motion; and rocking model, which simulates rocking motion. Moreover, we developed two kinds of rocking model: slide-rocking considered model, which considers the equations of both slide-rocking motion and non-slide-rocking motion; and non-slide-rocking model, which considers only the equation of non-slide-rocking motion. Then, simulations with sinusoidal inertial force input were conducted, changing values of friction coefficient. To validate this dynamic model, a miniature experiment was conducted. It is found that the non-slide-rocking model simulates movement of an FS rack well and better than the slide-rocking considered model in the aspect of translational and rocking movement. However, planar rotational movement is not simulated well with either model. Through this research, the knowledge is acquired that friction force plays a significant role in motion of an FS rack so that estimating and controlling friction coefficient is important in designing an FS rack.

scholarly journals Закономерности трения многоуровневых композиционных материалов, содержащих высокодисперсные частицы фуллереновой сажи

2021 ◽  
Vol 47 (5) ◽  
pp. 7
Author(s):  
И.А. Кобыхно ◽  
Ф.А. Юнусов ◽  
А.Д. Бреки ◽  
О.В. Толочко ◽  
А.Г. Кадомцев
Keyword(s):  
Friction Coefficient ◽  
Carbon Fiber ◽  
Friction Force ◽  
Dry Friction ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Soot Concentration ◽  
Fiber Reinforced ◽  
Fullerene Soot ◽  
Reinforced Polymer

The paper presents the results of tribological studies of carbon fiber reinforced polymer filled with fullerene soot nanoparticles. It is shown that the dry friction coefficient of the materials does not change when the fullerene soot concentration increases up to 4wt%, but an increase in the friction force occurs due to the forces of intermolecular attraction, the resultant of which monotonically increases.

Preparation and In Vitro Evaluation of Resealed Erythrocytes as A New Trend in Treatment of Asthma

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
Mohammed Ibrahim ◽  
Alaa Zaky ◽  
Mohsen Afouna ◽  
Ahmed Samy
Keyword(s):  
In Vitro Release ◽  
Human Erythrocytes ◽  
The Body ◽  
Blood Levels ◽  
Time Interval ◽  
Burst Release ◽  
Prolonged Release ◽  
Nocturnal Asthma ◽  
Carrier Erythrocytes

Carrier erythrocytes are emerging as one of the most promising biological drug delivery systems investigated in recent decades. Beside its biocompatibility, biodegradability and ability to circulate throughout the body, it has the ability to perform extended release system of the drug for a long period. The ultimate goal of this study is to introduce a new carrier system for Salbutamol, maintaining suitable blood levels for a long time, as atrial to resolve the problems of nocturnal asthma medication Therefore in this work we study the effect of time, temperature as well as concentration on the loading of salbutamol in human erythrocytes to be used as systemic sustained release delivery system for this drug. After the loading process is performed the carrier erythrocytes were physically and cellulary characterized. Also, the in vitro release of salbutamol from carrier erythrocytes was studied over time interval. From the results it was found that, human erythrocytes have been successfully loaded with salbutamol using endocytosis method either at 25 Co or at 37 Co . The highest loaded amount was 3.5 mg/ml and 6.5 mg/ml respectively. Moreover, the percent of cells recovery is 90.7± 1.64%. Hematological parameters and osmotic fragility behavior of salbutamol loaded erythrocytes were similar that of native erythrocytes. Scanning electron microscopy demonstrated that the salbutamol loaded cells has moderate change in the morphology. Salbutamol releasing from carrier cell was 43% after 36 hours in phosphate buffer saline. The releasing pattern of the drug from loaded erythrocytes showed initial burst release in the first hour followed by a very slow release, obeying zero order kinetics. It concluded that salbutamol is successfully entrapped into erythrocytes with acceptable loading parameters and moderate morphological changes, this suggesting that erythrocytes can be used as prolonged release carrier for salbutamol.

Effect of shape/size and distribution of microgeometries of textures on tribo-performance of crankpin bearing

2021 ◽  
pp. 135065012110105
Author(s):  
Nguyen Van Liem ◽  
Wu Zhenpeng ◽  
Jiao Renqiang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Contact Force ◽  
Distribution Density ◽  
Hydrodynamic Lubrication ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Combined Model ◽  
Obvious Effect ◽  
Area Density

The effect of the shape/size and distribution of microgeometries of textures on improving the tribo-performance of crankpin bearing is proposed. Based on a combined model of the slider-crank mechanism dynamic and hydrodynamic lubrication, the distribution density, area density, and shape of spherical textures, square-cylindrical textures, wedge-shaped textures, and a hybrid between spherical texture and square-cylindrical texture on the crankpin bearing's tribo-performance are investigated under different operating conditions of the engine. The tribological characteristic of the crankpin bearing is then evaluated via the indexes of the oil film pressure p, asperity contact force, friction force, and friction coefficient of the crankpin bearing. The research results show that the distribution density with n = 12 and m = 6, and area density with α = 30% of various microtextures have an obvious effect on ameliorating the crankpin bearings tribo-performance. Concurrently, at the mixed lubrication region, the shape of the square-cylindrical texture on improving the tribo-performance is better than the other shapes of the spherical texture, wedge-shaped texture, and spherical and square-cylindrical texture. Particularly, all the average values of the asperity contact force, friction force, and friction coefficient with a square-cylindrical texture are significantly reduced by 14.6%, 19.5%, and 34.5%, respectively, in comparison without microtextures. Therefore, the microtextures of the spherical texture applied on the bearing surface can contribute to enhance the durability and decrease the friction power loss of the engine.

scholarly journals The Impact of Heat Treatment on the Behavior of a Hot-Dip Zinc Coating Applied to Steel During Dry Friction

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 660
Author(s):  
Dariusz Jędrzejczyk ◽  
Elżbieta Szatkowska
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Friction Coefficient ◽  
Dry Friction ◽  
Zinc Coating ◽  
Pin On Disc ◽  
The One ◽  
The Impact ◽  
Coating Hardness ◽  
Anticorrosion Properties

The analyzed topic refers to the wear resistance and friction coefficient changes resulting from heat treatment (HT) of a hot-dip zinc coating deposited on steel. The aim of research was to evaluate the coating behavior during dry friction after HT as a result of microstructure changes and increase the coating hardness. The HT parameters should be determined by taking into consideration, on the one hand, coating wear resistance and, on the other hand, its anticorrosion properties. A hot-dip zinc coating was deposited in industrial conditions (according EN ISO 10684) on disc-shaped samples and the chosen bolts. The achieved results were assessed on the basis of tribological tests (T11 pin-on-disc tester, Schatz®Analyse device, Sindelfingen, Germany), microscopic observations (with the use of optical and scanning microscopy), EDS (point and linear) analysis, and microhardness measurements. It is proved that properly applied HT of a hot-dip zinc coating results in changes in the coating’s microstructure, hardness, friction coefficient, and wear resistance.

Friction and Wear Behaviors of Solid Lubricants/Polyimide Composites in Liquid Mediums

2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Alkaline Solution ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricants ◽  
Polyimide Composites ◽  
Inorganic Fillers ◽  
Ptfe Composites

The tribological properties of polyimide (PI) composites reinforced with graphite or MoS2 sliding in liquid alkali and water as well as dry friction were investigated using a ring-on-ring tester. The results show that the friction coefficient (μ) and wear rate (W) for both graphite/PI and MoS2/PI composites in different liquid mediums are μdry>μwater >μalkali and Wwater>Wdry >Walkali. Results also indicate that the friction coefficient and wear rate of the PI composites filled with different solid lubricants are μMoS2 >μgraphite and W MoS2 >Wgraphite in different liquid mediums. In addition, the hydrophobic inorganic fillers are fit for the reinforcement of polymer-based composites sliding in liquid mediums. It is also concluded from the authors’ work that the wear rate and friction coefficient of polymer-based (such as PI, PTFE) composites in the alkali lubricated conditions is lowest among all the friction conditions. This may be attributed to the ionic hydration in the alkaline solution.

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