Flexure based gripper to grasp hollow objects by internal surface interaction

2021 ◽  
pp. 095440622110498
Author(s):  
Rajesh Kumar ◽  
Harsh Yadav ◽  
Varan Gupta ◽  
Jitendra P Khatait
Keyword(s):  
Internal Surface ◽  
Surface Interaction ◽  
Design Development ◽  
Friction Forces ◽  
Normal Forces ◽  
Inner Surface

The paper focuses on the design, development, and evaluation of a gripper intended to hold hollow objects by interacting with the inner surface. The gripper moves towards the inside of the hollow object and grips it using the friction forces applied on the surface of the object. The design also ensures the application of variable normal forces on the surface of the object to be grasped. The mathematical architecture is verified using prototypes and experiments.

Influence of Inner Surface Defects on the Fatigue Strength of Pipe Subjected to Cyclic Internal Pressure

1978 ◽  
Vol 100 (4) ◽  
pp. 360-368
Author(s):  
Y. Yazaki ◽  
S. Hashirizaki ◽  
S. Nishida ◽  
C. Urashima
Keyword(s):  
Fatigue Strength ◽  
Internal Pressure ◽  
Test Specimen ◽  
Surface Defects ◽  
Fatigue Crack Initiation ◽  
Internal Surface ◽  
Fatigue Tests ◽  
Inner Surface ◽  
Surface Notch ◽  
Medium Diameter

Cyclic internal oil pressure fatigue tests were carried out on medium-diameter ERW pipes of API 5LX - X60 in an attempt to determine the influence of surface defects on the fatigue strength. Experimental factors investigated were the depth and location of internal surface notch in relation to the axis of pipe. The specimen was subjected to cyclic internal pressure, the cyclic rate being 0.3–0.5 Hz. During the test, Acoustic Emission (AE) techniques were applied to detect the fatigue crack initiation. Along with the aforementioned fatigue tests, pulsating tension fatigue tests were carried out on specimens with the same surface notches as the cyclic internal pressure fatigue test specimen.

Measurements of Forces Between a Synchronous Belt and a Pulley

2000 ◽  
Author(s):  
Martin Distner ◽  
Tomas Johannesson
Keyword(s):  
Load Distribution ◽  
Contact Forces ◽  
Automotive Application ◽  
Friction Forces ◽  
Running Time ◽  
Application Range ◽  
Normal Forces ◽  
Belt Speed ◽  
Pitch Difference ◽  
Static Conditions

Abstract In modern belt profiles, power is transmitted by both normal forces and friction forces. To control the load distribution between a belt and a pulley, avoiding power circulation and local tooth load peaks, it is necessary to take into account both types of forces. An analytical model for the load distribution has previously been presented by the authors. This work also introduces the effective pitch difference, EPD, which is the actual pitch difference between a pulley and a loaded belt. To examine these matters and verify the model, a series of 270 experiments was carried out in a two-pulley test rig. Parameters investigated are: torque, tension, belt speed, pitch difference and running time. All of the measurements were conducted under quasi-static conditions. The equipment used included a specially designed measurement pulley that can measure four different engagement forces. Experiments show that belt speed within automotive application range has no effect on load distribution, apart from engagement and disengagement peaks. Tooth flank normal forces and land area friction forces often work against each other. Belts with dissimilar pitch difference give rise to great differences in load distributions. Even a short running time causes a redistribution of the friction forces, although their sum remains constant. The results show that it is possible to tailor the load distribution by adjusting the EPD. This offers an opportunity to avoid power circulation and unnecessary high contact forces. Changing the EPD for the correct load distribution at each interaction is easily achieved by individual adjustment of the pulley radius.

Polishing Processing to Internal Surface of Non-Magnetic Pipe by Magnetic Abrasive Finishing

2008 ◽  
Vol 53-54 ◽  
pp. 137-140
Author(s):  
Y. Chen ◽  
X. Wang ◽  
C.J. Zhang
Keyword(s):  
Magnetic Force ◽  
Solution Method ◽  
Internal Surface ◽  
Special Equipment ◽  
Magnetic Abrasive Finishing ◽  
Surface Polishing ◽  
Abrasive Finishing ◽  
Inner Surface ◽  
Magnetic Force Line ◽  
Usual Tool

It is very difficult matter that polishes the internal surface of the pipe, especially to the thin pipe with the traditional surface technology. Because a usual tool cannot into the inner surface of the thin pipe and automation do not achieved easily. This paper brings up a new method that utilize the characteristic of the magnetic force line may penetrate the non-magnetic material, may using the magnetic abrasive finishing (MAF) method complete to the inner surface of the thin pipe precise polishing. The magnetic abrasive finishing does not need special equipment to complete the complex shape internal surface polishing. Moreover, we already obtained the famous processing effect through the experiment. Meanwhile this paper analyses some factors of influences efficiency, and propose some solution method.

scholarly journals In situ monitoring of internal surface temperature of the historic building envelope

2016 ◽  
Vol 11 (1) ◽  
pp. 77-84
Author(s):  
Veronika Labovská ◽  
Dušan Katunský
Keyword(s):  
Surface Temperature ◽  
Internal Surface ◽  
Building Envelope ◽  
In Situ Monitoring ◽  
Heat Accumulation ◽  
Historical Building ◽  
External Temperature ◽  
Inner Surface ◽  
Real Behavior

Abstract Historical building envelope is characterized by a large accumulation that impact is mainly by changing the inner surface temperature over time. The minimum value of the inner surface temperature is set Code requirements. In the case of thermal technology assessment of building envelope contemplates a steady state external temperature and internal environment, thereby neglecting the heat accumulation capacity of building envelopes. Monitoring surface temperature in real terms in situ shows the real behavior of the building envelope close to reality. The recorded data can be used to create a numerical model for the simulation.

Modeling the Effect of Surface Roughness on the Adhesion, Contact and Friction in Micro-Electro-Mechanical Systems (MEMS) Interfaces

2003 ◽  
Author(s):  
Noureddine Tayebi ◽  
Andreas A. Polycarpou
Keyword(s):  
Surface Texturing ◽  
Static Friction ◽  
Normal Operation ◽  
Root Mean Square Roughness ◽  
Adhesion Forces ◽  
Sensors And Actuators ◽  
Micro Electro Mechanical Systems ◽  
Friction Forces ◽  
Normal Forces ◽  
Adhesion Contact

It has been experimentally shown that surface texturing (roughening) decreases the effect of intermolecular adhesion forces that are significant in MEMS applications. These forces can hinder normal operation of sensors and actuators as well as micro-engines where they might increase friction, which could be catastrophic. In this paper, a model that predicts the effects of roughness, asymmetry, and flatness on the adhesion, contact, and friction forces in MEMS interfaces is presented. The three key parameters used to characterize the roughness the asymmetry and the flatness of a surface topography are the root-mean-square roughness (RMS), skewness and kurtosis, respectively. It is predicted that surfaces with high RMS, high kurtosis and positive skewness exhibit lower adhesion and static friction coefficient, even at extremely low external normal forces.

Study of Finishing Mechanism for Internal Surface Using Magnetic Force Generated by Rotating Magnetic Field

2009 ◽  
Vol 416 ◽  
pp. 406-410 ◽  
Author(s):  
Xin Gai Yao ◽  
Yan Hong Ding ◽  
Gang Ya ◽  
Wei Wei Liu ◽  
Yuan Zhang
Keyword(s):  
Magnetic Field ◽  
Material Removal ◽  
Magnetic Force ◽  
Sliding Friction ◽  
Internal Surface ◽  
Rotating Magnetic Field ◽  
Inner Surface ◽  
Tube Type ◽  
Main Factors ◽  
Magnetic Abrasives

In the paper, a new method of using rotating magnetic field generated by a stator of alternative electromotor to finish the inner surface of tube-type workpiece is proposed. Force and movements of magnetic abrasive are analyzed. The finishing mechanism is analyzed and the sliding, friction and scratching between magnetic abrasives and the workpiece inner surface may be main factors of material removal as the non-mechanical relative motion is produced.

Multi Rigid-Body Contact Dynamics With Regularized Friction

2015 ◽  
Author(s):  
Farnood Gholami ◽  
Mostafa Nasri ◽  
József Kövecses
Keyword(s):  
Linear Complementarity Problem ◽  
Complementarity Problem ◽  
Mathematical Formulation ◽  
Contact Problems ◽  
Linear Complementarity ◽  
Contact Dynamics ◽  
Friction Forces ◽  
Body Contact ◽  
Normal Forces ◽  
Multibody Contact

A novel mathematical formulation in terms of a linear complementarity problem is introduced for multibody contact problems. In this approach, contacts are characterized based on kinematic constraints while the friction forces are simultaneously regularized and incorporated into the formulation. The variables of the resulting linear complementarity problem are only the normal forces. The main advantage of this formulation is a significant dimension reduction in the resulting linear complementarity problem in comparison with its counterpart formulations in the literature. Moreover, the dimension can be even further reduced by removing the velocity variables from the formulation. The proposed formulation is examined for benchmark examples yielding promising results.

scholarly journals SELECTION OF THE EXTERNAL WALL ROUNDING ANGLE OPTIMAL RADIUS

2021 ◽  
pp. 69-76
Author(s):  
Volodymyr Semko ◽  
Oleg Yurin ◽  
Natliia Mahas ◽  
Anastasiia Norka ◽  
Yevhen Pylypenko
Keyword(s):  
Heat Flow ◽  
Outer Surface ◽  
Internal Surface ◽  
Outer Wall ◽  
Mineral Wool ◽  
Temperature Fields ◽  
Radius Of Curvature ◽  
Outer Corner ◽  
Inner Surface ◽  
Optimal Radius

The article analyzes one of the ways to increase the heat-protective properties of thebuilding corner - rounding the outer surface of the outer wall the corner . The walls of houses nearthe outer corner, due to their configuration, have less heat-insulating properties than the walls inother areas. This is due to the fact that the area of heat flow perception on the inner surface of thewalls at an angle less than the area of heat transfer on the outer surface. Convective heat exchangenear the inner surface of the corner, due to the inhibition of air movement is less than in other areas,so the amount of heat coming from the indoor air to the wall surface is less. For climatic conditionsof Poltava region the research of temperature fields of calculated sections of the wall (withoutrounding of a corner, with rounding of a wall of various radius an external surface) with definitionof a heat stream size, the minimum temperature on an internal surface of a wall and the resulted heattransfer resistance is carried out. The dependences of the rounding radius of the wall outer surfaceon the heat flow passing through the design area of the wall outer corner, brick consumption withinthe design area, insulation consumption within the design area, the amount of room area reductiondue to rounding the wall for five design schemes. The analysis of dependences the constructed graphsshowed that the intensive reduction of the heat flux passing through the calculated section occurs ata radius of the wall outer surface rounding of 0.9 m and more; a slight decrease in the area of theroom due to the rounding of the wall occurs to a radius of curvature of 1.4 m; intensive reduction ofbrick volume within the calculated area occurs when the radius of curvature is more than 0.8 m,similarly to mineral wool up to 0.7 m. It is determined that the optimal radius of curvature of theouter wall is 0.8 m, it will increase the thermal properties of the angle and reduce the heat transfercoefficient by the transmission of the external enclosing structure of the building as a whole.

scholarly journals CRITERIA FOR CLASSIFICATION OF IN-PIPE ROBOTS

2018 ◽  
Vol 3 (3) ◽  
pp. 89-100
Author(s):  
Людмила Ворочаева ◽  
Lyudmila Vorochaeva ◽  
Сергей Савин ◽  
Sergey Savin
Keyword(s):  
Contact Interaction ◽  
Contact Element ◽  
Practical Significance ◽  
Clear Understanding ◽  
Friction Forces ◽  
Contact Points ◽  
Detailed Classification ◽  
Inner Surface

In-pipe robots are developed for solving a diverse set of tasks, all of which have to do with monitoring and repairs of pipelines. These tasks include generation of maps of pipelines, detecting defects, anomalies and matter deposits on the inner surface of the pipe, studying the inner surface of the pipe in order to determine if it needs to be repaired and if it is possible to repair it, gathering information on the properties of the inner surface of the pipe and studying the change of these properties. These tasks have practical significance and their automation with robots is economically beneficial. Considering the variety of the existing in-pipe robot designs, it is important to have a way to categorize them and have a clear understanding which tasks are suitable for particular in-pipe robots. To this end, the detailed classifications of in-pipe robots can be used. This paper presents a survey of classifications of in-pipe robots. The previously proposed criteria for such classifications are discussed. The ambiguity of the commonly used classifications is highlighted. The paper presents a more detailed classification, based on eight criteria: 1) types of pipe surfaces that a robot can interact with, 2) controllability of a robot (distinguishing fully passive and active robots), 3) type of contact interaction with the inner surface of the pipe, 4) controllability of normal reactions and 5) controllability of friction forces in contact points or surfaces, 6) contact element types, 7) motor type, 8) transmission type. Combination of these criteria allows highlighting particular features of the existing in-pipe robot designs, simplifying the analysis of problem range that the robot can solve.

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