An Experimental Optical Three-axis Tactile Sensor for Micro-Robots

Robotica ◽  
2005 ◽  
Vol 23 (4) ◽  
pp. 457-465 ◽  
Author(s):  
Masahiro Ohka ◽  
Yasunaga Mitsuya ◽  
Isamu Higashioka ◽  
Hisanori Kabeshita
Keyword(s):  
Normal Force ◽  
Axial Loading ◽  
Tactile Sensor ◽  
Horizontal Displacement ◽  
Shearing Force ◽  
Gray Scale ◽  
Rubber Sheet ◽  
The Relationship ◽  
Sensing Characteristics ◽  
Calibration Coefficients

This paper describes a micro-optical three-axis tactile sensor capable of sensing not only normal force, but also shearing force. The normal force was detected from the integrated gray-scale values of bright pixels emitted from the contact area of conical feelers. The conical feelers were formed on a rubber sheet surface that maintains contact with an optical waveguide plate. The shearing force was detected from horizontal displacement of the conical feeler. In the experiments, a precise multi-axial loading machine was developed to measure sensing characteristics of the present sensor. Results show that the normal force was specified uniquely under combined force conditions and that the shearing force was specified by modifying the relationship between the shearing force and the horizontal displacement on the basis of normal force. We formulated a set of expressions to derive the normal force and the shearing force by taking into account this modification. Furthermore, calibration coefficients were identified for transforming the integration of gray-scale values into the normal force and for transforming the horizontal displacement into the shearing force. This result suggests that the expressions can estimate the normal force and the shearing force in wide-load regions.

Sensing characteristics of an optical three-axis tactile sensor under combined loading

Robotica ◽  
2004 ◽  
Vol 22 (2) ◽  
pp. 213-221 ◽  
Author(s):  
Masahiro Ohka ◽  
Yasunaga Mitsuya ◽  
Yasuaki Matsunaga ◽  
Shuichi Takeuchi
Keyword(s):  
Normal Force ◽  
Tangential Force ◽  
Testing Machine ◽  
Tactile Sensor ◽  
Combined Loading ◽  
Vertical Force ◽  
Load Testing ◽  
Brass Plate ◽  
The Coefficient Of Friction ◽  
Sensing Characteristics

This paper describes precision enhancement of an optical three-axis tactile sensor capable of detecting both normal force and tangential force. The sensor's single cell consists of a columnar feeler and 2-by-2 conical feelers. We have derived equations to precisely estimate the three-axis force from the area-sum and area-difference of the conical feelers' contact areas by taking into account wrench-length shrinkage caused by a vertical force. To evaluate the equations and determine constants included in the equations, we performed a series of calibration experiments using a manipulator-mounted tactile sensor and a combined load-testing machine. Subsequently. to evaluate the tactile sensor's practicality. it was mounted on the end of a robotic manipulator which rubbed flat specimens such as brass plates with step-heights of δ=0.05, 0.1, 0.2 mm and a brass plate with no step-height. We showed from the experimental data that the optical three-axis tactile sensor can detect not only the step-heights but also the distribution of the coefficient of friction, and that the sensor can detect fine plate inclination with accuracy to about ±0.4°.

scholarly journals Experimental Study on Shear Failure Mechanism and the Identification of Strength Characteristics of the Soil-Rock Mixture

2019 ◽  
Vol 2019 ◽  
pp. 1-25
Author(s):  
Shaorui Sun ◽  
Feng Zhu ◽  
Jihong Wei ◽  
Wuchao Wang ◽  
Huilin Le
Keyword(s):  
Failure Mechanism ◽  
Shear Failure ◽  
Horizontal Displacement ◽  
Strength Characteristics ◽  
Laboratory Model ◽  
Gravel Size ◽  
Shear Process ◽  
Composition Materials ◽  
The Relationship ◽  
Laboratory Models

Soil-rock mixture (SRM) is a special geological material that has the unique properties of rock or soil. Studies on the strength characteristics of the SRM have very important theoretical significance and practical value. In this study, the gravel proportions, gravel sizes, gravel shapes, and repetitive results of shear experiments are considered in laboratory experiments and for the identification of strength parameters. To the gravel shapes, from the angle of the composition materials of SRM, the experimental samples include samples with breccia gravels and with subrounded gravels. And, in this study, the laboratory model experiment is used to research the strength characteristics of SRM. In addition, the shear failure mechanism is used to establish the relationship between the microfailure mechanism and the macrostrength parameters identification. Taking gravel proportion, gravel size, gravel shape, and repetitive shear process as the influencing factors of the SRM, the laboratory models have been remolded, and laboratory direct shear experiments have been carried out. The shear deformation laws of the SRM are researched on the basis of the analysis of the curves of shear stress and the horizontal displacement.

scholarly journals Deformation Control Method of the Antislide Pile under Trapezoidal Load in the Zhangjiawan Landslide

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Hao Wang ◽  
Zhiying Lv ◽  
Hongyu Qin ◽  
Jianwei Yue ◽  
Jianwei Zhang
Keyword(s):  
Driving Force ◽  
Shear Force ◽  
Control Method ◽  
Slip Surface ◽  
Quadratic Function ◽  
Bending Moment ◽  
Site Investigation ◽  
Horizontal Displacement ◽  
Pile Head ◽  
The Relationship

Antislide piles are set in the Zhangjiawan landslide area, where the general features of the bedrock below the slip surface include upper weak and lower hard strata. Based on a site investigation, the horizontal displacement of the antislide pile head is 14.8 cm, which is not conducive to the stability of the landslide. In the study, a displacement calculation method for the pile under trapezoidal load is proposed for a colluvial landslide controlling. Furthermore, factors affecting the deformation and internal forces of the pile were also studied. The results indicated that (1) when the embedded length of an antislide pile increases, the horizontal displacement on the pile and maximum absolute shear force decrease, while the bending moment of the pile exhibits opposite trends; (2) the relationship between maximum shear force and maximum bending moment is linear with increasing driving force of landslide; and (3) increase in the ratio of the driving force between the pile head and slip surface (q0/q1) steadily increases the horizontal displacement of the pile. The relationship between the distribution of the driving force (q0/q1) and the reasonable embedded length of a pile is a quadratic function, which can be used to determine the reasonable embedded length of a pile under the action of rectangular or triangular loads. It is very useful to use the above method to guide the design of antislide piles in similar areas.

A Microfluidic-Based Tactile Sensor for 3-DOF Force/Torque Detection

2015 ◽  
Author(s):  
Yichao Yang ◽  
Zhili Hao
Keyword(s):  
Soft Lithography ◽  
Shear Force ◽  
Normal Force ◽  
Three Dimensional ◽  
Tactile Sensor ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Torque Sensor ◽  
Resistance Increase ◽  
3D Microstructure

This paper reports on a microfluidic-based tactile sensor capable of detecting forces along two directions and torque about one direction. The 3-Degree-Of-Freedom (3-DOF) force/torque sensor encompasses a symmetric three-dimensional (3D) microstructure embedded with two sets of electrolyte-enabled distributed resistive transducers underneath. The 3D microstructure is built into a rectangular block with a loading-bump on its top and two microchannels at its bottom. Together with electrode pairs distributed along the microchannel length, electrolyte in each microchannel functions as a set of three resistive transducers. While a normal force results in a resistance increase in the two sets of transducers, a shear force causes opposite resistance changes in the two sets of transducers. Conversely, a torque leads to the opposite resistance changes in the two side transducers in each set. Soft lithography and CNC molding are combined to fabricate a prototype tactile sensor. The experimental results validate the feasibility of using this microfluidic-based tactile sensor for 3-DOF force/torque detection.

scholarly journals Design, Motivation and Evaluation of a Full-Resolution Optical Tactile Sensor

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 928 ◽  
Author(s):  
Carmelo Sferrazza ◽  
Raffaello D’Andrea
Keyword(s):  
High Resolution ◽  
Deep Neural Network ◽  
Normal Force ◽  
Tactile Sensor ◽  
High Accuracy ◽  
Image Sensors ◽  
Random Pattern ◽  
Full Resolution ◽  
Sense Of Touch ◽  
Modern Image

Human skin is capable of sensing various types of forces with high resolution and accuracy. The development of an artificial sense of touch needs to address these properties, while retaining scalability to large surfaces with arbitrary shapes. The vision-based tactile sensor proposed in this article exploits the extremely high resolution of modern image sensors to reconstruct the normal force distribution applied to a soft material, whose deformation is observed on the camera images. By embedding a random pattern within the material, the full resolution of the camera can be exploited. The design and the motivation of the proposed approach are discussed with respect to a simplified elasticity model. An artificial deep neural network is trained on experimental data to perform the tactile sensing task with high accuracy for a specific indenter, and with a spatial resolution and a sensing range comparable to the human fingertip.

Research on the Mechanism of Coordinate Polishing Crankshaft Crankpin with Abrasive Belt

2011 ◽  
Vol 487 ◽  
pp. 457-461 ◽  
Author(s):  
M. Zhang ◽  
Yun Huang ◽  
L. Zhang
Keyword(s):  
Surface Roughness ◽  
Constant Velocity ◽  
Horizontal Displacement ◽  
Schematic Diagram ◽  
Uniform Rotation ◽  
Swing Angle ◽  
Abrasive Belt ◽  
Long Time ◽  
The Relationship ◽  
Grinding Time

Under the conditions of crankshaft uniform rotation, the schematic diagram of coordinate polishing crankpin was analyzed and found that the grinding time and speech changed, when the abrasive grinded crankpin. At the same time, the surface roughness was the relevant with the grinding time, grinding for a long time the roughness value was low, grinding time was short then the roughness value was high. In order to ensure that the surface roughness was homogeneity, so that the abrasive grinded the grinding point in the same time, in other words, the abrasive grinded crankpin in the constant velocity. And then the abrasive grinding crankpin was analyzed in the constant velocity, the crankshaft angle was draw the relationship between horizontal displacement and the swing angle. Simultaneity, adopted the level cylinder and the oscillating cylinder mutual moving, that resulted in the mechanism following the rotation of crankshaft back and forth movement, it was due to the weight of mechanism and the lag of the cylinder, and finally the mechanism of lag error was analyzed.

scholarly journals Body Composition and Kinematic Analysis of the Grab Start in Youth Swimmers

2014 ◽  
Vol 42 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Ahmet Alptekin
Keyword(s):  
Body Composition ◽  
Vertical Velocity ◽  
Center Of Mass ◽  
Random Order ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Kinematic Parameters ◽  
Total Distance ◽  
Block Time ◽  
The Relationship

Abstract The purposes of this study were to compare the kinematic variables in youth swimmers during the grab start between sexes and to investigate the relationship between body composition and kinematic variables of the participants. Six female (Mage = 13.71 ± 0.49 yrs) and seven male (Mage = 14.00 ± 1.07 yrs) swimmers participated in this study. All participants were required to perform grab start tests in random order (three trials by each participant), while the best attempt was analyzed. Nineteen kinematic parameters consisting of block time, flight time, flight distance, total time, total distance, horizontal and vertical displacement of the center of mass (CM) at take-off, horizontal and vertical displacement of the CM at entry, height of take-off and entry, relative height of take-off, horizontal and vertical velocity of the CM at take-off, horizontal and vertical velocity of the CM at entry, angle of take-off, angle of entry and angle of knee at block were analyzed. Out of the 19 evaluated kinematic parameters, a statistical difference between the female and male group was found only in the total distance. Therefore, both female and male groups are considered as only one group and merged after analyzing the results. Statistical analysis showed positive and negative correlations between horizontal / vertical velocity of CM at take-off and several kinematic variables (e.g. angle of entry (rhorizontal = -.868, p=.000 / rvertical = .591, p=.02), total distance (rhorizontal = .594, p=.02 / rvertical = .54, p=.04), and height of take-off (rvertical = .888, p=.000), respectively). On the other hand, positive and negative correlations were found between somatotype components and several kinematic variables (e.g. horizontal displacement of CM at entry (rendomorphy = -.626, p=.013), angle of entry (rmesomorphy = -.686, p=.005 / rectomorphy = .52, p=.047), total distance (rendomorphy = -.626, p=.012), and height of take-off (rendomorphy = -.633, p=.011 / rectomorphy = .515, p=.05)). In conclusion, results show that in order to be successful at grab start performance, a swimmer should target to get higher horizontal velocity of CM at take-off and optimize the angle of take-off so this movement form supplies more total distance to the swimmer. Coaches should consider improving start performance and adding start training to regular training sessions. Moreover, youth male and female swimmers can participate together in the grab start training

Large Sideward Deflections of Two-Hinged Circular Arches

1971 ◽  
Vol 93 (4) ◽  
pp. 1268-1274 ◽  
Author(s):  
Donald A. Dadeppo ◽  
Robert Schmidt
Keyword(s):  
Applied Load ◽  
Normal Force ◽  
Bending Moment ◽  
Point Load ◽  
Elliptic Integrals ◽  
Graphical Form ◽  
Shearing Force ◽  
Underlying Theory

Deflections and stress resultants are calculated for hinged-hinged circular arches subjected to a horizontal point load at the crown. The underlying theory is based on the Bernoulli-Euler hypothesis. The magnitudes of deflections are unrestricted. The solutions are expressed in terms of Legendre’s elliptic integrals of the first and second kind. Calculated results are presented in graphical form. These include deflected configurations and load-deflection curves, as well as normal force, shearing force, and bending moment diagrams for arches with three different subtending angles and three different values of the applied load on each arch.

An Advanced Residual Stress Determination for 3D Cylinder Structure

2005 ◽  
Vol 490-491 ◽  
pp. 62-66 ◽  
Author(s):  
Jian Luo ◽  
Guillaume Montay ◽  
Jian Lu
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Hole Drilling ◽  
Stress Determination ◽  
Residual Stress Determination ◽  
Incremental Hole Drilling ◽  
Drilling Technique ◽  
The Relationship ◽  
Calibration Coefficients

For measuring in-depth residual stress in 3D cylinder structure easily in this paper, the semi-destructive incremental hole drilling technique combined with finite element method is used, the calibration coefficients of 3D cylinder components are calculated, and the relationship between strain and stress is determined, the changes of calibration coefficients are analysed, the residual stress of one steering joint of automobile is measured, and the errors of residual stress are discussed.

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