Recognition of In-Hand Manipulation along with Rolling Contact using Orbital Motion of Contact Points on Object Surface

2006 ◽  
Author(s):  
Masahiro Kondo ◽  
Jun Ueda ◽  
Yoshio Matsumoto ◽  
Tsukasa Ogasawara
Keyword(s):  
Orbital Motion ◽  
Rolling Contact ◽  
Object Surface ◽  
Contact Points

Neighboring Degree-of-Approximation Equating Method for Computing Contact Points between Robot and Convex Object

1993 ◽  
Vol 5 (1) ◽  
pp. 19-25
Author(s):  
Makoto Kaneko ◽  
◽  
Kazuo Tanie ◽  
Keyword(s):  
Contact Point ◽  
Degree Of Approximation ◽  
Mathematical Framework ◽  
Object Surface ◽  
Convex Object ◽  
Contact Points ◽  
Nearest Point ◽  
Before And After ◽  
Compliant Joint ◽  
Computation Scheme

With a proper combination of compliant joint and position- controlled joint, a link system changes its posture with keeping contact between link system and environment. This is so-called Self-Posture Changing Motion (SPCM) and conveniently used to detect a contact point between robot and unknown object. In conventional approach, a contact point has been computed as an intersecting point between two different link postures before and after SPCM. In general, this computation scheme gives us a contact point with unsatisfactory approximation, while it furnishes us with an exact contact point for a sharp-edged object. In this paper, we first introduces a concept of degree-of-approximation, which is defined as the distance between a computed point and the nearest point over the object surface, and then propers the Neighboring Degree-Of Approximation Equating Method which improves the degree-of-approximation drastically and provides exact contact points not only for a sharp· edged object but also for a constant curved object. Mathematical framework is provided for the proposed computation scheme. Finally, the effectiveness of the proposed scheme is verified by simulations.

SIMULTANEOUS CONTROL OF GRASP/MANIPULATION AND CONTACT POINTS WITH ROLLING CONTACT

2005 ◽  
Vol 38 (1) ◽  
pp. 415-420 ◽  
Author(s):  
Akira Nakashima ◽  
Kenji Nagase ◽  
Yoshikazu Hayakawa
Keyword(s):  
Rolling Contact ◽  
Contact Points ◽  
Simultaneous Control

Experimental Study of Rolling Contact Fatigue Life of Zirconia Ceramic Ball

2010 ◽  
Vol 152-153 ◽  
pp. 1272-1275
Author(s):  
Jing Ling Zhou ◽  
Wei Ming Zuo ◽  
Xiao Yang Chen ◽  
Guo Qing Wu
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Fatigue Properties ◽  
Zirconia Ceramic ◽  
Contact Points ◽  
Pure Rolling ◽  
Contact Fatigue Life ◽  
Life Tests ◽  
Weibull Theory

A newly developed pure rolling fatigue test rig with three contact points for bearing balls was used to perform rolling contact fatigue (RCF) tests and the fatigue properties of two kinds of zirconia ceramic balls produced with different materials composition and identical technologies were compared. Ball surfaces were examined after failure with optical microscopy and scanning electron microscopy. It was identified by tests that the failure mode of zirconia ceramic balls was surface spall. Life tests data, summarized in accordance with the Weibull theory, showed that the life of two kinds of zirconia balls was close, and no remarkable difference in the divergence between the tested two kinds of balls was found

Grinding Wheel Motion and Force During Plaque Removal by Rotational Atherectomy in Angulated Coronary Artery

2018 ◽  
Author(s):  
Yihao Zheng ◽  
Jingxuan Lyu ◽  
Yang Liu ◽  
Jason Lo ◽  
Ata Susamaz ◽  
...  
Keyword(s):  
Coronary Artery ◽  
High Speed ◽  
Orbital Motion ◽  
Force Transducer ◽  
Rotational Atherectomy ◽  
Grinding Wheel ◽  
Contact Points ◽  
Operating Technique ◽  
Flow Restoration ◽  
Vessel Dissection

Rotational atherectomy (RA) utilizes a high-speed diamond grinding wheel to remove the calcified atherosclerotic plaque off the vessel wall via a catheter inside an artery for blood flow restoration and treatment of cardiovascular diseases. RA in angulated lesions is challenging due to the geometric constrains on the wheel motion, potentially leading to vessel dissection and perforation. To understand the grinding wheel motion and force during RA in curved arteries, experiments were conducted based on 3D printed anatomically accurate coronary artery phantoms with plaster coating as the plaque surrogate, a high-speed camera, and a multi-axis force transducer. Results showed that the grinding wheel did not orbit inside right coronary artery phantom which led to a highly biased ground region aligned with several contact points between the guidewire and the arterial wall. The grinding wheel orbital motion facilitated an even treatment of several segments in left anterior descending coronary artery phantom. The grinding force, ranging from 0.05 to 0.20 N, increased with the wheel rotational speed when the wheel orbited and was insensitive to the wheel speed without wheel orbital motion. This study explained the clinically observed guidewire bias from the engineering perspective and further revealed the RA mechanism of action in angulated artery, which may assist to improve the device design and the operating technique.

Wheelset Mechanics During Wheelclimb Derailment

1984 ◽  
Vol 51 (3) ◽  
pp. 680-686 ◽  
Author(s):  
A. Karmel ◽  
L. M. Sweet
Keyword(s):  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Equations Of Motion ◽  
Rolling Contact ◽  
Nonlinear Dynamic Model ◽  
Normal Forces ◽  
Contact Points ◽  
Vertical Roll ◽  
Predicted Values ◽  
Railroad Vehicle

An analysis of the mechanics and dynamics of a railroad vehicle wheelset during flange contact and wheelclimb derailment is presented. The theoretical model includes wheelset lateral, vertical, roll, yaw, and axle rotation degrees of freedom, plus lateral displacement of the truck frame. The equations of motion are based on the kinematics and dynamics of the wheelset subject to constraints imposed by wheel/rail contact geometry. These constraints are used to compute creepages and normal forces at the wheel/rail contact points, needed as inputs to the Kalker Simplified Theory of rolling contact. Computational methods for simulation of the nonlinear dynamic model are discussed. Results of the simulation demonstrate the significance of the various degrees of freedom on wheelset motion and on predicted values of the derailment quotient (Q/P).

Numerical Study for a Catamaran Gripper-Monopile Mechanism of a Novel Offshore Wind Turbine Assembly Installation Procedure

2017 ◽  
Author(s):  
Lars Ivar Hatledal ◽  
Houxiang Zhang ◽  
Karl Henning Halse ◽  
Hans Petter Hildre
Keyword(s):  
Numerical Simulations ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Numerical Study ◽  
Weather Conditions ◽  
Rolling Contact ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Contact Points ◽  
Turbine Installation

Current methods for installation of offshore wind turbines are all sensitive to the weather conditions and the present cost level of offshore wind power is more than twice the cost of land-based units, increasing with water depth. This paper presents numerical simulations of a novel experimental gripper design to reduce the environmental effects applied to a catamaran type of vessel during wind turbine installation. In SFI MOVE project in NTNU Aalesund, our team proposed a novel wind turbine installation process. A new catamaran vessel will carry pre-assembled wind turbines to the installation location. Two new designed grippers on the deck will make a lifting operation to install the wind turbine onto the turbine foundation. Three prismatic grippers with several rolling contact points at the end are attached in an arc at the catamaran’s aft, designed to grasp the turbine foundation in order to make a connection between the two in the horizontal plane. This paper will only emphasize the contact responses between the turbine foundation and the three grippers during the wind turbine installation process. Numerical simulations are carried out using the virtual prototyping framework Vicosim which is developed by NTNU Aalesund. The simulation results show validation of a key part of the proposed new wind turbine installation idea.

scholarly journals Modeling and Control of 2D Grasping under Rolling Contact Constraints between Arbitrary Shapes: A Riemannian-Geometry Approach

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Suguru Arimoto ◽  
Morio Yoshida
Keyword(s):  
Lagrange Equation ◽  
Contact Point ◽  
Equation Of Motion ◽  
Second Fundamental Form ◽  
Rigid Bodies ◽  
Rolling Contact ◽  
Modeling And Control ◽  
Contact Points ◽  
Dimensional Object ◽  
And Control

Modeling, control, and stabilization of dynamics of two-dimensional object grasping by using a pair of multijoint robot fingers are investigated under rolling contact constraints and arbitrariness of the geometry of the object and fingertips. First, modeling of rolling motion between 2D rigid bodies with arbitrary shape is treated under the assumption that the two contour curves coincide at the contact point and share the same tangent. The rolling constraints induce the Euler equation of motion that is parameterized by a pair of arclength parameters and constrained onto the kernel space as an orthogonal complement to the image space spanned from all the constraint gradients. Furthermore, it is shown that all the Pfaffian forms of the rolling constraints are integrable in the sense of Frobenius and therefore the rolling contacts are regarded as a holonomic constraint. The Euler-Lagrange equation of motion of the overall fingers/object system is rederived together with a couple of first-order differential equations that express evolution of contact points in terms of quantities of the second fundamental form. A control signal called “blind grasping” is defined and shown to be effective in maintenance or stabilization of grasping without using the details of object shape and parameters or external sensing. An extension of the Dirichlet-Lagrange stability theorem to a system of DOF-redundancy under constraints is discussed by introducing a Morse-Bott function and deriving its Hessian, in a special case that the object to be grasped is a parallelepiped.

A photoelectron microscope study of surfaces

1989 ◽  
Vol 47 ◽  
pp. 10-11
Author(s):  
W. Engel ◽  
M. Kordesch ◽  
A. M. Bradshaw ◽  
E. Zeitler
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Field Strength ◽  
Uv Light ◽  
Physical Property ◽  
Photon Flux ◽  
Mercury Lamp ◽  
Object Surface ◽  
The Sixties ◽  
Physical Features

Photoelectron microscopy is as old as electron microscopy itself. Electrons liberated from the object surface by photons are utilized to form an image that is a map of the object's emissivity. This physical property is a function of many parameters, some depending on the physical features of the objects and others on the conditions of the instrument rendering the image.The electron-optical situation is tricky, since the lateral resolution increases with the electric field strength at the object's surface. This, in turn, leads to small distances between the electrodes, restricting the photon flux that should be high for the sake of resolution.The electron-optical development came to fruition in the sixties. Figure 1a shows a typical photoelectron image of a polycrystalline tantalum sample irradiated by the UV light of a high-pressure mercury lamp.

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