A tactile sensor based on thin-plate deformation

Robotica ◽  
1994 ◽  
Vol 12 (4) ◽  
pp. 343-351 ◽  
Author(s):  
R.E. Ellis ◽  
S.R. Ganeshan ◽  
S.J. Lederman
Keyword(s):  
Large Scale ◽  
Tactile Sensor ◽  
Thin Plates ◽  
Local Geometry ◽  
Normal Strain ◽  
Tactile Sensors ◽  
Accuracy Measurement ◽  
Scale Properties ◽  
Task Specification ◽  
The Individual

SUMMARYTraditionally, tactile sensors have been designed using compliant, rubber-like materials; when such a sensitized gripper grasps or otherwise manipulates an object, the normal strain deformation in the compliant material is sampled. The resulting information can be used to deduce simple local geometry of the contact, but the transduction process does not typically permit use of the individual strains in determining large-scale properties of the object (e.g., the inertia). Measurements of inertial parameters of grasped objects require accurate, low-hysteresis transduction that few tactile sensors currently provide.An alternative is to work from the task specification, and determine the tactile information that is necessary to accomplish the task. Here, we consider how to sense the length and mass of a uniform object that is gripped in a gravitational field, and show the design and assessment of a new kind of tactile sensor that is based on the theory of the deformation of thin plates. Features of this design include its potentially rugged realization, and its high-accuracy measurement that is more typical of force sensors than of tactile sensors.

scholarly journals Understanding the Role of Geometric and Electronic Structure in Bioinspired Catalyst Design: the Case of Formate Dehydrogenase

2021 ◽  
Author(s):  
Mingjie Liu ◽  
Azadeh Nazemi ◽  
Michael Taylor ◽  
Aditya Nandy ◽  
Chenru Duan ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Density Functional ◽  
Large Scale ◽  
Formate Dehydrogenase ◽  
Molecular Complexes ◽  
Catalyst Design ◽  
Local Geometry ◽  
Structural Variations ◽  
Screening Study ◽  
The Individual

The design of bioinspired synthetic inorganic molecular complexes is challenging, due to a lack of understanding of enzyme action and the degree to which that action can be translated into mimics. Exemplary of this challenge is the reversible conversion of formate into CO2 by formate dehydrogenase (FDH) enzymes with Mo/W centers in large molybdopterin cofactors. Despite numerous efforts to synthesize Mo/W-containing molecular complexes, none have been demonstrated to reproduce the full reactivity of FDH. Here, we carry out a large-scale, high-throughput screening study on all mononuclear Mo/W complexes currently deposited in Cambridge Structural Database (CSD). Using density functional theory, we systematically investigate the individual effects of metal identity, ligand identity, oxidation state, and coordination number on structural, electronic and catalytic properties. We compare our results on molecular complexes with quantum mechanics/molecular mechanics simulations on a representative FDH enzyme to further elucidate the influence of the enzyme environment. These comparisons reveal that the enzyme environment primarily influences the metal-local geometry, and these metal-local structural variations can improve catalysis. Through a series of computational mutations on molecular complexes, we extend beyond the CSD structures to further identify the limits of varied chalcogen and metal identity. This broad set and comparison reveal relatively little variation of electronic properties of the metal center due to the presence of the enzyme environment or changes in metal-distant ligand chemistry. Instead, these properties are found to be much more sensitive to the identity of the metal and the nature of the bound terminal chalcogen.

Models, Practices and Methods of Reading: Evolution in Time and Space

2009 ◽  
pp. 59-64
Author(s):  
Yulia P. Melentyeva
Keyword(s):  
Large Scale ◽  
Social Groups ◽  
National Program ◽  
Time And Space ◽  
Lack Of Information ◽  
The Individual

In recent years as public in general and specialist have been showing big interest to the matters of reading. According to discussion and launch of the “Support and Development of Reading National Program”, many Russian libraries are organizing the large-scale events like marathons, lecture cycles, bibliographic trainings etc. which should draw attention of different social groups to reading. The individual forms of attraction to reading are used much rare. To author’s mind the main reason of such an issue has to be the lack of information about forms and methods of attraction to reading.

scholarly journals A Vibrissa-Inspired Highly Flexible Tactile Sensor: Scanning 3D Object Surfaces Providing Tactile Images

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1572
Author(s):  
Lukas Merker ◽  
Joachim Steigenberger ◽  
Rafael Marangoni ◽  
Carsten Behn
Keyword(s):  
Steel Wire ◽  
Sense Organ ◽  
Tactile Sensor ◽  
Tactile Sensors ◽  
Measuring Device ◽  
3D Object ◽  
Torque Transducer ◽  
Sense Of Touch ◽  
Important Basis ◽  
Support Reactions

Just as the sense of touch complements vision in various species, several robots could benefit from advanced tactile sensors, in particular when operating under poor visibility. A prominent tactile sense organ, frequently serving as a natural paragon for developing tactile sensors, is the vibrissae of, e.g., rats. Within this study, we present a vibrissa-inspired sensor concept for 3D object scanning and reconstruction to be exemplarily used in mobile robots. The setup consists of a highly flexible rod attached to a 3D force-torque transducer (measuring device). The scanning process is realized by translationally shifting the base of the rod relative to the object. Consequently, the rod sweeps over the object’s surface, undergoing large bending deflections. Then, the support reactions at the base of the rod are evaluated for contact localization. Presenting a method of theoretically generating these support reactions, we provide an important basis for future parameter studies. During scanning, lateral slip of the rod is not actively prevented, in contrast to literature. In this way, we demonstrate the suitability of the sensor for passively dragging it on a mobile robot. Experimental scanning sweeps using an artificial vibrissa (steel wire) of length 50 mm and a glass sphere as a test object with a diameter of 60 mm verify the theoretical results and serve as a proof of concept.

Soft magnetic skin for super-resolution tactile sensing with force self-decoupling

2021 ◽  
Vol 6 (51) ◽  
pp. eabc8801
Author(s):  
Youcan Yan ◽  
Zhe Hu ◽  
Zhengbao Yang ◽  
Wenzhen Yuan ◽  
Chaoyang Song ◽  
...  
Keyword(s):  
External Disturbance ◽  
Super Resolution ◽  
Tactile Sensor ◽  
Human Robot Interaction ◽  
Tactile Sensors ◽  
Dexterous Manipulation ◽  
Robot Interaction ◽  
Flexible Film ◽  
Challenging Tasks ◽  
External Forces

Human skin can sense subtle changes of both normal and shear forces (i.e., self-decoupled) and perceive stimuli with finer resolution than the average spacing between mechanoreceptors (i.e., super-resolved). By contrast, existing tactile sensors for robotic applications are inferior, lacking accurate force decoupling and proper spatial resolution at the same time. Here, we present a soft tactile sensor with self-decoupling and super-resolution abilities by designing a sinusoidally magnetized flexible film (with the thickness ~0.5 millimeters), whose deformation can be detected by a Hall sensor according to the change of magnetic flux densities under external forces. The sensor can accurately measure the normal force and the shear force (demonstrated in one dimension) with a single unit and achieve a 60-fold super-resolved accuracy enhanced by deep learning. By mounting our sensor at the fingertip of a robotic gripper, we show that robots can accomplish challenging tasks such as stably grasping fragile objects under external disturbance and threading a needle via teleoperation. This research provides new insight into tactile sensor design and could be beneficial to various applications in robotics field, such as adaptive grasping, dexterous manipulation, and human-robot interaction.

STAND-UP MOTION SUPPORT BY A MOBILE MANIPULATOR SYSTEM WITH HIGH SPEED TACTILE SENSORS

2011 ◽  
Vol 08 (03) ◽  
pp. 181-195
Author(s):  
ZHAOXIAN XIE ◽  
HISASHI YAMAGUCHI ◽  
MASAHITO TSUKANO ◽  
AIGUO MING ◽  
MAKOTO SHIMOJO
Keyword(s):  
Fuzzy Logic ◽  
Feedback Control ◽  
Experimental Verification ◽  
High Speed ◽  
Center Of Pressure ◽  
Tactile Sensor ◽  
Mobile Manipulator ◽  
Tactile Sensing ◽  
Robot Arm ◽  
Tactile Sensors

As one of the home services by a mobile manipulator system, we are aiming at the realization of the stand-up motion support for elderly people. This work is charaterized by the use of real-time feedback control based on the information from high speed tactile sensors for detecting the contact force as well as its center of pressure between the assisted human and the robot arm. First, this paper introduces the design of the tactile sensor as well as initial experimental results to show the feasibility of the proposed system. Moreover, several fundamental tactile sensing-based motion controllers necessary for the stand-up motion support and their experimental verification are presented. Finally, an assist trajectory generation method for the stand-up motion support by integrating fuzzy logic with tactile sensing is proposed and demonstrated experimentally.

Flexibility Effects in a Single Link Robotic Manipulator

1993 ◽  
Author(s):  
C. Nataraj
Keyword(s):  
Large Scale ◽  
Robotic Manipulator ◽  
Flexible Beam ◽  
Rotating Speed ◽  
Weighted Residuals ◽  
Individual Interaction ◽  
Single Link ◽  
Rigid Mass ◽  
The Individual ◽  
Future Work

Abstract A single link robotic manipulator is modeled as a rotating flexible beam with a rigid mass at the tip and accurate energy expressions are derived. The resulting partial differential equations are solved using an approximate method of weighted residuals. From the solutions, coupling between axial and flexural deformations and the interactions with rigid body motions are rigorously analyzed. The emphasis in the current paper is not on an exhaustive analysis of existing systems but it is rather intended to compare and highlight the various flexibility effects in a relatively simple system. Hence, a nondimensional parametric analysis is performed to determine the effect of several parameters (including the rotating speed) on the errors and the individual interaction effects are discussed. Comparison with previous work in the field shows important phenomena often ignored or buried in large scale numerical analyses. Future work including application to multi-link robots is outlined.

Nonparametric Object Recognition With a New Tactile Sensor

1992 ◽  
Author(s):  
S. Unsal ◽  
A. Shirkhodaie ◽  
A. H. Soni
Keyword(s):  
Decision Making ◽  
Object Recognition ◽  
Sensory Information ◽  
Tactile Sensor ◽  
Operating Environment ◽  
Tactile Sensors ◽  
Binary Array ◽  
Software And Hardware ◽  
Robotic Applications

Abstract Adding sensing capability to a robot provides the robot with intelligent perception capability and flexibility of decision making. To perform intelligent tasks, robots are highly required to perceive their operating environment, and react accordingly. With this regard, tactile sensors offer to extend the scope of intelligence of a robot for performing tasks which require object touching, recognition, and manipulation. This paper presents the design of an inexpensive pneumatic binary-array tactile sensor for such robotic applications. The paper describes some of the techniques implemented for object recognition from binary sensory information. Furthermore, it details the development of software and hardware which facilitate the sensor to provide useful information to a robot so that the robot perceives its operating environment during manipulation of objects.

scholarly journals A low-cost, human-like, high-resolution, tactile sensor based on optical fibers and an image sensor

2018 ◽  
Vol 15 (4) ◽  
pp. 172988141878363 ◽  
Author(s):  
Utku Büyükşahin ◽  
Ahmet Kırlı
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Fiber Optic ◽  
Low Cost ◽  
Experimental Studies ◽  
Main Idea ◽  
Tactile Sensor ◽  
Image Sensor ◽  
Sensor Design ◽  
Tactile Sensors

Tactile sensors are commonly a coordinated group of receptors forming a matrix array meant to measure force or pressure similar to the human skin. Optic-based tactile sensors are flexible, sensitive, and fast; however, the human fingertip’s spatial resolution, which can be regarded as the desired spatial resolution, still could not be reached because of their bulky nature. This article proposes a novel and patented optic-based tactile sensor design, in which fiber optic cables are used to increase the number of sensory receptors per square centimeter. The proposed human-like high-resolution tactile sensor design is based on simple optics and image processing techniques, and it enables high spatial resolution and easy data acquisition at low cost. This design proposes using the change in the intesity of the light occured due to the deformation on contact/measurement surface. The main idea is using fiber optic cables as the afferents of the human physiology which can have 9 µm diameters for both delivering and receiving light beams. The variation of the light intensity enters sequent mathematical models as the input, then, the displacement, the force, and the pressure data are evaluated as the outputs. A prototype tactile sensor is manufactured with 1-mm spatial and 0.61-kPa pressure measurement resolution with 0–15.6 N/cm2 at 30 Hz sampling frequency. Experimental studies with different scenarios are conducted to demonstrate how this state-of-the-art design worked and to evaluate its performance. The overall accuracy of the first prototype, based on different scenarios, is calculated as 93%. This performance is regarded as promising for further developments and applications such as grasp control or haptics.

scholarly journals HUMAN ENERGY UTILIZATION AND EFFECTIVENESS IN SMALL AND MARGINAL FARM HOLDINGS

2018 ◽  
Vol 6 (11) ◽  
pp. 163-171
Author(s):  
Tandra Mondal ◽  
Pranab Kumar Nag
Keyword(s):  
Large Scale ◽  
Energy Utilization ◽  
Hand Tools ◽  
Present Contribution ◽  
Land Preparation ◽  
Farm Work ◽  
Farm Mechanization ◽  
Power Tiller ◽  
Paddy Cultivation ◽  
The Individual

In India, small and marginal farmers have emerged as a distinct and dominant category. While farm mechanization represents a rapid transformation from traditional to modern methods of farming, it is not uniform across the crops and regions. The level of mechanization, however, remains scattered due to the compulsiveness to the situation dominated by the economic layout of farm holdings, land size, and large-scale deprivation of access to the technology suitable to small holdings. This present contribution elucidates the extent of use tools and machinery among the rice farmers of the state of Wes Bengal, India. Analysis revealed that the total number of man-days involved in paddy cultivation was 120-140 per ha, i.e., 900-1000 man-hours depending upon the availability of labour, tools, and machinery used for the individual operation. Analysis of farm work in small and marginal holdings evolved that over 90% of the total number of farmers use either tractor or power tiller for land preparation. Use of the animal-drawn country plough is gradually phased out in the study regions. For sowing and transplanting operations are primarily manual methods using hand tools. The study provided an insight of the issues of work methods and practices of the farmworkers in small and marginal farm holdings.

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