Simultaneous Control of Grasp/Manipulation and Contact Points of an Object with Rolling Contact by Two-fingered Robot Hand with Constraint of Degrees of Freedom

2005 ◽  
Vol 41 (6) ◽  
pp. 481-490 ◽  
Author(s):  
Akira NAKASHIMA ◽  
Kenji NAGASE ◽  
Yoshikazu HAYAKAWA ◽  
Masaki MITA
Keyword(s):  
Degrees Of Freedom ◽  
Rolling Contact ◽  
Robot Hand ◽  
Contact Points ◽  
Simultaneous Control

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

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).

In-hand forward and inverse kinematics with rolling contact

Robotica ◽  
2017 ◽  
Vol 35 (12) ◽  
pp. 2381-2399 ◽  
Author(s):  
Lei Cui ◽  
Jie Sun ◽  
Jian S. Dai
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Rolling Contact ◽  
Moving Frame ◽  
Robot Hand ◽  
Robotic Hands ◽  
Geometric Framework ◽  
Univariate Polynomial ◽  
Forward And Inverse Kinematics ◽  
Exponential Formula

SUMMARYRobotic hands use rolling contact to manipulate a grasped object to a desired location, even when the finger and the palm linkage mechanisms lack degrees of freedom. This paper presents a systematic approach to the forward and inverse kinematics of in-hand manipulation. The moving frame method in differential geometry is integrated into the product of exponential formula to establish a pure geometric framework of the kinematics of a robot hand. The forward and inverse kinematics of a multifingered hand are obtained in terms of the joint rates and contact trajectories. A two-fingered planar robot hand and a three-fingered spatial robot hand are used to demonstrate the proposed approach. The proposed formulation amounts to solving a univariate polynomial, providing an alternative to the existing ones that require numerical integration.

Miniaturized Pneumatic Artificial Muscles Actuating a Bio-Inspired Robot Hand

2013 ◽  
Author(s):  
Thomas E. Pillsbury ◽  
Ryan M. Robinson ◽  
Norman M. Wereley
Keyword(s):  
Degrees Of Freedom ◽  
Full Scale ◽  
Constitutive Relationship ◽  
Force Density ◽  
Human Hand ◽  
Artificial Muscles ◽  
Specific Work ◽  
Robotic Hand ◽  
Robot Hand ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are used in robotics applications for their light-weight design and superior static performance. Additional PAM benefits are high specific work, high force density, simple design, and long fatigue life. Previous use of PAMs in robotics research has focused on using “large,” full-scale PAMs as actuators. Large PAMs work well for applications with large working volumes that require high force and torque outputs, such as robotic arms. However, in the case of a compact robotic hand, a large number of degrees of freedom are required. A human hand has 35 muscles, so for similar functionality, a robot hand needs a similar number of actuators that must fit in a small volume. Therefore, using full scale PAMs to actuate a robot hand requires a large volume which for robotics and prosthetics applications is not feasible, and smaller actuators, such as miniature PAMs, must be used. In order to develop a miniature PAM capable of producing the forces and contractions needed in a robotic hand, different braid and bladder material combinations were characterized to determine the load stroke profiles. Through this characterization, miniature PAMs were shown to have comparably high force density with the benefit of reduced actuator volume when compared to full scale PAMs. Testing also showed that braid-bladder interactions have an important effect at this scale, which cannot be modeled sufficiently using existing methods without resorting to a higher-order constitutive relationship. Due to the model inaccuracies and the limited selection of commercially available materials at this scale, custom molded bladders were created. PAMs created with these thin, soft bladders exhibited greatly improved performance.

Simultaneous Control of Natural and Extra Degrees-of-Freedom by Isometric Force and EMG Null Space Activation

2021 ◽  
pp. 863-868
Author(s):  
Sergio Gurgone ◽  
Daniele Borzelli ◽  
Paolo De Pasquale ◽  
Denise J. Berger ◽  
Tommaso Lisini Baldi ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Null Space ◽  
Isometric Force ◽  
Simultaneous Control

scholarly journals Virtualization of Robotic Hands Using Mobile Devices †

Robotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 81
Author(s):  
Santiago T. Puente ◽  
Lucía Más ◽  
Fernando Torres ◽  
and Francisco A. Candelas
Keyword(s):  
Degrees Of Freedom ◽  
Robotic Hand ◽  
Robot Hand ◽  
Real Time Control ◽  
Robotic Hands ◽  
Robot Operating System ◽  
Server Side ◽  
Time Control ◽  
Unity 3D ◽  
Real Robot

This article presents a multiplatform application for the tele-operation of a robot hand using virtualization in Unity 3D. This approach grants usability to users that need to control a robotic hand, allowing supervision in a collaborative way. This paper focuses on a user application designed for the 3D virtualization of a robotic hand and the tele-operation architecture. The designed system allows for the simulation of any robotic hand. It has been tested with the virtualization of the four-fingered Allegro Hand of SimLab with 16 degrees of freedom, and the Shadow hand with 24 degrees of freedom. The system allows for the control of the position of each finger by means of joint and Cartesian co-ordinates. All user control interfaces are designed using Unity 3D, such that a multiplatform philosophy is achieved. The server side allows the user application to connect to a ROS (Robot Operating System) server through a TCP/IP socket, to control a real hand or to share a simulation of it among several users. If a real robot hand is used, real-time control and feedback of all the joints of the hand is communicated to the set of users. Finally, the system has been tested with a set of users with satisfactory results.

scholarly journals Complex Bogie Modeling Incorporating Advanced Friction Wedge Components

2009 ◽  
Author(s):  
Brian Sperry ◽  
Corina Sandu ◽  
Brent Ballew
Keyword(s):  
Dynamic Behavior ◽  
Degrees Of Freedom ◽  
Model Simulation ◽  
Surface Friction ◽  
Rigid Bodies ◽  
Operating Conditions ◽  
Normal Operation ◽  
Contact Points ◽  
Modeling Software ◽  
Simulation Results

This research focuses on the dynamic behavior of the three-piece bogie that supports the freight train car bodies. While the system is relatively simple, in that there are very few parts involved, the behavior of the bogie is somewhat more complex. Our research focuses primarily on the behavior of the friction wedges under different operating conditions that are seen under normal operation. The Railway Technologies Laboratory (RTL) at Virginia Tech has been developing a model to better capture the dynamic behavior of friction wedges using 3-D modeling software. In previous years, a quarter-truck model, and half-truck variably damped model have been developed using MathWorks MATLAB®. This year, research has focused on the development of a half-truck variably damped model with a new (curved surface) friction wedge, and a half-truck constantly damped model, both using the MATLAB® based software program. Currently a full-truck variably damped model has been created using LMS Virtual.Lab. This software allows for a model that is more easily created and modified, as well as allowing for a much shorter simulation time, which became a necessity as more contact points, and more complex inputs were needed to increase the accuracy of the simulation results. The new model consists of seven rigid bodies: the bolster, two sideframes, and four wedges. We have also implemented full spring nests on each sideframe, where in previous models equivalent spring forces were used. The model allows six degrees-of-freedom for the wedges and bolster: lateral, longitudinal, and vertical translations, as well as pitch, roll, and yaw. The sideframes are constrained to two degrees-of-freedom: vertical and longitudinal translations. The inputs to the model are vertical and longitudinal translations or forces on the sideframes, which can be set completely independent of each other. The model simulation results have been compared with results from NUCARS®, an industrially-used train modeling software developed by the Transportation Technology Center, Inc. (TTCI), a wholly owned subsidiary of the Association of American Railroads (AAR), for similar inputs, as well as experimental data from warping tests performed at TTCI.

Analytic and Experimental Study of the Load Distribution on Spline Joints Length Considering the Contact Rigidity of the Bearing Surfaces

2012 ◽  
Vol 162 ◽  
pp. 74-83 ◽  
Author(s):  
Dan Mărgineanu ◽  
E. Mărgineanu ◽  
E.S. Zăbavă ◽  
A. M. Fârtă
Keyword(s):  
Experimental Study ◽  
Mechanical System ◽  
Elastic Properties ◽  
Load Distribution ◽  
Degrees Of Freedom ◽  
Surface Profile ◽  
Contact Rigidity ◽  
Contact Points ◽  
Actual Load ◽  
Contact Surfaces

The spline joints transmit torque from shafts to rotors by multiple contact surfaces. The joint's mechanical system is, therefore, undetermined, i.e. the number of contact points is much larger than the number of restricted degrees of freedom. Thus, the actual load distribution is greatly influenced by the joints elements elastic properties and their geometrical errors and surface profile. In this paper, an analytical and experimental study for the load distribution on the in joints length caused by the finite rigidity of the joints elements is presented.

Sign in / Sign up

Export Citation Format

Share Document