scholarly journals A Novel 3D Ring-Based Flapper Valve for Soft Robotic Applications

Robotics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 2
Author(s):  
Kelly Low ◽  
Devin R. Berg ◽  
Perry Y. Li
Keyword(s):  
The Body ◽  
Variable Control ◽  
Simultaneous Control ◽  
Size Constraints ◽  
Rotationally Symmetric ◽  
Spatial Configurations ◽  
Soft Manipulator ◽  
Design And Testing ◽  
Robotic Applications ◽  
Manipulator Control

In this paper, the design and testing of a novel valve for the intuitive spatial control of soft or continuum manipulators are presented. The design of the valve is based on the style of a hydraulic flapper valve, but with simultaneous control of three pressure feed points, which can be used to drive three antagonistically arranged hydraulic actuators for positioning soft robots. The variable control orifices are arranged in a rotationally symmetric radial pattern to allow for an inline mounting configuration of the valve within the body of a manipulator. Positioning the valve ring at various 3D configurations results in different pressurizations of the actuators and corresponding spatial configurations of the manipulator. The design of the valve is suitable for miniaturization and use in applications with size constraints such as small soft manipulators and surgical robotics. Experimental validation showed that the performance of the valve can be reasonably modeled and can effectively drive an antagonistic arrangement of three actuators for soft manipulator control.

Modeling of half-scale human bodies in active body positions for apparel design and testing

2017 ◽  
Vol 29 (6) ◽  
pp. 807-821 ◽  
Author(s):  
Arzu Vuruskan ◽  
Susan P. Ashdown
Keyword(s):  
Size Range ◽  
Test Validity ◽  
The Body ◽  
Apparel Design ◽  
Linear Measurements ◽  
Content Type ◽  
Fit Testing ◽  
Pattern Development ◽  
Novel Concept ◽  
Design And Testing

Purpose The design and testing of clothing for activewear requires complex assessments of the suitability of the clothing when the body is in motion. The purpose of this paper is to investigate full body 3D scanning of active body poses in order to develop “watertight” digital models and half-scale dress forms to facilitate design, pattern making and fit analyses. Issues around creating a size set of scans in order to facilitate fit testing of activewear across a size range were also explored. Design/methodology/approach Researchers experimented to discover effective methods for 3D body capture in the cycling position and reconstruction of the body in a reliable way. In total, 25 cyclists were scanned and size representatives were selected from these participants. Methods of creating half-scale forms were developed that make optimum use of modern materials and technologies. Half-scale dress forms were created in two active positions in a range of sizes for fit testing and design. A set of half-scale and full-scale bike shorts in two styles were manufactured and fit tested on the half-scale forms compared to fit testing on the scan participants to test validity of this method of assessing fit. Findings Issues in capturing and reconstructing areas occluded in the scanning process, and reconstructing the interface with the bicycle seat were addressed. Active digital forms were developed across the size range, from which both digital avatars and physical mannequins were developed for pattern development and fit testing. The production and use of precisely half-scaled tools for garment testing was achieved and validated by comparing fit test results in active positions on the half-scale forms and on participants who were scanned to create these forms. Originality/value Design modifications for active positions to date are based on linear measurements alone, which do not define the 3D body adequately. Despite much research using body scanners, only limited data exist on the body in active poses, and the concept of creating half-scale forms by scanning fit models throughout the size range in active body positions is a novel concept. The progress made in resolving material and process experiments in creating the actual half-scale forms, and testing their suitability for fit testing provides a basis for further research aimed at developing similar dress forms for other activewear garments.

scholarly journals ROBOTIZED SYSTEM OF POINTING THE GRIPPER-CUTTING DEVICE ON THE TREE

2018 ◽  
Vol 8 (1) ◽  
pp. 198-207 ◽  
Author(s):  
Александр Мохирев ◽  
Aleksandr Mokhirev ◽  
Иван Мохирев ◽  
Ivan Mohirev ◽  
Дмитрий Морозов ◽  
...  
Keyword(s):  
Control System ◽  
The Body ◽  
Constant Concentration ◽  
Complex Operation ◽  
Touch Sensor ◽  
Automatic Guidance ◽  
Operator Fatigue ◽  
Experienced Operator ◽  
Machine Control ◽  
Manipulator Control

To date, the improvement of forest machines is aimed at increasing productivity using modern information sys-tems. The most complex operation in logging, which requires the experience and skill of the operator, is the manipulator control when gripper-cutting device is pointed to a tree. At "hard" capture of the tree as a result of inaccurate pointing of the manipulator, the sawed tree growing around the undergrowth is damaged, expensive equipment is damaged, there is a risk of tree falling in the undetermined direction, saw mechanism is destroyed. Also the time for pointing the manipulator and capture the tree increases, which significantly reduces the productivity of work. With constant concentration on a complex operation, the operator quickly becomes fatigued, which reduces his/her efficiency and attention. Not precise guidance of the manipulator and "hard" capture of the tree occurs quite often and can happen even with an experienced operator. The operations are performed by one algorithm, which means that they can be automated. In order to eliminate the above-mentioned shortcomings, a system of automatic guidance of gripper-cutting device on a tree and its gripping is proposed. It consists, apart from both technological equipment of the machine itself, a computer with a logging machine control system, two distance sensors, and touch sensor. The distance sensors are installed on the pick-up device and determine the location of the tree. The information from the sensors is fed to the computer of the forest machine, which controls the operating mechanisms of the manipulator of the forest machine. Controlled by the machine control system, actuators of hydromanipulator guide the gripper-cutting device onto the tree. The touch sensor is mounted on the body of the gripping device. When you touch the tree with the sensor, the tree is captured. With such an implementation, the accuracy and speed of guiding the cutting device onto the tree is increased, which leads to a reduction in operator fatigue, increased productivity of the forest machine, reduction of damage to trees and gripping device due to the partial automation of the process of guiding the cutting device on the tree and its capture

Stress Concentration Due to a Hemispherical Pit at a Free Surface

1954 ◽  
Vol 21 (1) ◽  
pp. 57-62
Author(s):  
R. A. Eubanks
Keyword(s):  
Free Surface ◽  
Present Method ◽  
Infinite Medium ◽  
The Body ◽  
Hydrostatic Tension ◽  
Rotationally Symmetric ◽  
Method Of Solution ◽  
In Series ◽  
Axis Of Symmetry ◽  
Plane At Infinity

Abstract This paper contains a solution in series form for the stresses and displacements around a hemispherical pit at a free surface of an elastic body. The problem is idealized by considering a semi-infinite medium which otherwise is bounded by a plane. At infinity the body is assumed to be in a state of plane hydrostatic tension perpendicular to the axis of symmetry of the pit. The present method of solution may be generalized to loadings which are not rotationally symmetric. Numerical results are given for the variation along the axis of symmetry of the normal stress which is parallel to the tractions at infinity; these results are compared with the known corresponding numerical values appropriate to the two-dimensional analog of the present problem.

The Effect of a Vibratory Lumber Orthosis on Walking Velocity in Patients with Parkinson's Disease

2009 ◽  
Vol 33 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Kamiar Ghoseiri ◽  
Bijan Forogh ◽  
Mohammad Ali Sanjari ◽  
Ahlam Bavi
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neurological Diseases ◽  
The Body ◽  
Lumbar Region ◽  
Vibratory Stimulus ◽  
Vibratory Stimulation ◽  
Gait Stability ◽  
Walking Velocity ◽  
Design And Testing

This paper explores the use of biofeedback to improve gait in Parkinson's disease (PD) and, in particular, reports on the design and testing of a new vibratory orthosis. The orthosis causes a rhythmic vibratory stimulus to be applied to one or other side of the lumbar region. The stimulus is synchronized with stepping through the use of heel-located switches; each switch controls the stimulus to the corresponding side of the body. In the experimental evaluation it was hypothesized that step-synchronized, vibratory stimulation applied to the lumbar region will lead to an increase in walking velocity in patients with idiopathic Parkinson's disease. Subjects were asked to carry out walking trials under two conditions. In one condition, the vibratory orthosis was active; in the other condition the vibratory orthosis was inactive. Walking velocity was measured over a straight, 10 m walkway. A comparison between the two conditions using a paired t-test showed a significant increase in walking velocity when the vibratory orthosis was active, compared with the inactive condition. It was speculated that use of the vibratory orthosis, which stimulates proprioceptive receptors, may lead to an improvement in gait, stability and may support gait re-education in PD patients. It was also suggested that the results may inform future ideas for rehabilitation of similar neurological diseases.

On the Stability of Rotation of a Rotor With Rotationally Unsymmetric Inertia and Stiffness Properties

1961 ◽  
Vol 28 (4) ◽  
pp. 567-570 ◽  
Author(s):  
S. H. Crandall ◽  
P. J. Brosens
Keyword(s):  
Three Dimensional ◽  
The Body ◽  
Uniform Rotation ◽  
Stiffness Properties ◽  
Principal Axes ◽  
Rotationally Symmetric ◽  
Speed Range ◽  
Stiffness Characteristics ◽  
The Stability ◽  
Gyroscopic Coupling

The stability of uniform rotation of a rigid body about a principal axis of inertia is analyzed for the case where there is a diametral inertia inequality and there is an elastic restoring mechanism with a diametral stiffness inequality which rotates with the body. This model is an idealization for systems such as a two-bladed propeller rotating on a flexible shaft whose stiffness characteristics are not rotationally symmetric. It is found that many such systems possess unstable speed ranges. The instability may be due to either type of asymmetry alone or due to the interaction of the two. Quantitative analytical results are obtained which relate the unstable speed range to the gyroscopic coupling, the inertia inequality, the stiffness inequality, and the relative orientation of the principal axes of inertia with respect to the principal axes of stiffness. Three-dimensional stability surfaces are plotted to give a qualitative overview of the interplay of the various parameters.

scholarly journals Generalized Linear Product Homotopy Algorithms and the Computation of Reachable Surfaces

2004 ◽  
Vol 4 (3) ◽  
pp. 226-234 ◽  
Author(s):  
Hai-Jun Su ◽  
J. Michael McCarthy ◽  
Layne T. Watson
Keyword(s):  
Polynomial Systems ◽  
The Body ◽  
Algebraic Surfaces ◽  
Degree Of Freedom ◽  
Homotopy Algorithm ◽  
Spatial Configurations ◽  
Spherical Wrist ◽  
Homotopy Algorithms ◽  
Three Degree Of Freedom ◽  
Serial Chains

In this paper, we apply a homotopy algorithm to the problem of finding points in a moving body that lie on specific algebraic surfaces for a given set of spatial configurations of the body. This problem is a generalization of Burmester’s determination of points in a body that lie on a circle for five planar positions. We focus on seven surfaces that we term “reachable” because they correspond to serial chains with two degree-of-freedom positioning structures combined with a three degree-of-freedom spherical wrist. A homotopy algorithm based on generalized linear products is used to provide a convenient estimate of the number of solutions of these polynomial systems. A parallelized version of this algorithm was then used to numerically determine all of the solutions.

scholarly journals Aerial Manipulator Control Method Based on Generalized Jacobian

2021 ◽  
Vol 33 (2) ◽  
pp. 231-241
Author(s):  
Takahiro Ikeda ◽  
Kenichi Ohara ◽  
Akihiko Ichikawa ◽  
Satoshi Ashizawa ◽  
Takeo Oomichi ◽  
...  
Keyword(s):  
Coordinate System ◽  
Unmanned Aerial Vehicle ◽  
Control Method ◽  
The Body ◽  
Degree Of Freedom ◽  
Bridge Inspection ◽  
Generalized Jacobian ◽  
Aerial Manipulator ◽  
Aerial Vehicle ◽  
Manipulator Control

This paper describes a control method for an aerial manipulator on an unmanned aerial vehicle (UAV) by using a generalized Jacobian (GJ). Our task is to realize visual check of bridge inspection by employing a UAV with a multi-degree-of-freedom (DoF) manipulator on its top. The manipulator is controlled by using the GJ. Subsequently, by comparing the aerial manipulator control with a conventional Jacobian experimentally, we discovered that the accuracy of the control improved by applying the GJ. The manipulator has three DoFs in the X-Z plane of the UAV coordinate system. The experiment shows that the manipulator controlled with the GJ can compensate for the pose error of the body by 54.5% and 47.7% in the X- and Z-axes, respectively.

scholarly journals The Roles of Vision, Space, and the Body in Interpreting Unfamiliar Serbian and English Idiomatic Expressions

2014 ◽  
Vol 25 (30) ◽  
pp. 11-30 ◽  
Author(s):  
Dušan Stamenković ◽  
Austin Bennett ◽  
Mihailo Antović
Keyword(s):  
Cognitive Linguistics ◽  
Engineering Students ◽  
Spatial Information ◽  
Body Part ◽  
The Body ◽  
Target Language ◽  
Abstract Concepts ◽  
Human Body Part ◽  
Idiomatic Expressions ◽  
Spatial Configurations

The present paper investigates whether lexicalized visuo-spatial configurations and/or an explicit reference to a human body part can facilitate the interpretation of unknown idioms by comparing the levels of correct interpretation of unknown English and Serbian idiomatic expressions. Two groups of respondents, American and Serbian engineering students, had the task to interpret literally translated idiomatic expressions from a target language they were not familiar with (Serbian or English). The idioms were divided into three groups: (1) visuo-spatial bodily idioms, (2) bodily idioms only, and (3) non-bodily idioms. The goal was to test whether references to visuo-spatial information and/or parts of the body would help respondents interpret the expressions correctly. Our results, compiled from both groups of respondents, suggest that there are significant differences for the three scores, with the combined visuo-spatial and bodily components taking the lead, the bodily component only coming second, and the non-bodily idioms falling strikingly far behind. This could provide support to the well-known assumptions of cognitive linguistics that visuo-spatial configurations and embodiment play a major role in the construction of abstract concepts.

Hybrid external control for two robot coordinated motion

Robotica ◽  
1996 ◽  
Vol 14 (2) ◽  
pp. 141-153 ◽  
Author(s):  
Véronique Perdereau ◽  
Michel Drouin
Keyword(s):  
External Control ◽  
Coordinated Motion ◽  
New Approach ◽  
Simultaneous Control ◽  
Control Scheme ◽  
Control Schemes ◽  
Simulation Results ◽  
The One ◽  
Robotic Applications

SUMMARYIn the field of robotic applications based on the coordinated motion of two manipulators, it seems that very few control schemes work efficiently. The best way to achieve the simultaneous control of object trajectory and forces applied to it, is to implement control schemes that are extended versions of one arm hybrid force'position control. The aim of this paper is not to review all existing solutions but rather to analyze and compare them from simulation results with a new solution presented here. The control scheme is an application of the one arm hybrid external control that we had previously developed. The main results of this theory are summarized in this paper. This radically new approach for a cooperation task has some advantages compared to other methods mentioned in this paper.

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