The Elastica With End-Load Flip-Over

1988 ◽  
Vol 55 (4) ◽  
pp. 845-848 ◽  
Author(s):  
J. F. Wilson ◽  
J. M. Snyder
Keyword(s):  
Cantilever Beam ◽  
Abrupt Change ◽  
Robotic Manipulators ◽  
Finite Deformations ◽  
Follower Load ◽  
System Parameters ◽  
Small Increment ◽  
Elastic Curves ◽  
Manipulator Arm

A high flexure manipulator arm is modeled as an elastic cantilever beam with a tip payload and an eccentric tip follower load that drives the arm. Shapes of the resulting elastic curves for finite deformations (the elastica) are calculated in terms of nondimensional system parameters. For critical combinations of these parameters, a small increment in the driving follower load causes an abrupt change in the shape of the elastica. The abrupt change in tip angle is typically of the order of π radians. These results are applicable to the design of high flexure robotic manipulators.

Actuator Gain Distributions in Serial Robotic Manipulators to Meet Specified Task Requirements

2008 ◽  
Author(s):  
Oziel Rios ◽  
Delbert Tesar
Keyword(s):  
Configuration Management ◽  
Robotic Manipulators ◽  
Effective Length ◽  
Management Problem ◽  
Motor Speed ◽  
Analytic Process ◽  
Performance Specifications ◽  
Finite Set ◽  
Manipulator Arm ◽  
System Output

A serial robotic manipulator arm is a complex electro-mechanical system whose performance is highly characterized by its actuators. The actuator itself is a complex nonlinear system whose performance can be represented by the speed and torque capabilities of its motor and its accuracy depends on the resolution of the encoder as well as its ability to resist deformations under load. The mechanical gain associated with the transmission is critical to the overall performance of the actuator since it amplifies the motor torque thus improving the force capability of the manipulator housing it, reduces the motor speed to a suitable output speed operating range, enables an improvement in responsiveness (acceleration) and amplifies the stiffness improving the precision under load of the overall system. In this work, a basic analytic process that can be used to manage the actuator gain parameters to obtain an improved arm design based on a set of desired/required performance specifications will be laid out. Key to this analytic process is the mapping of the actuator parameters (speed, torque, stiffness and encoder resolution) to their effective values at the system output via the mechanical gains of the actuators as well as the effective mechanical gains of the manipulator. This forward mapping of the actuator parameters allows the designer to determine how each of the parameters influences the functional capacity of the serial manipulator arm. The actuator gains are then distributed along the effective length of the manipulator to determine the distribution effects on the performance capabilities of the system. The analytic formulation is used to address the issue of configuration management of serial robotic manipulators where the goal is to assemble a system from a finite set of components that meets some required performance specifications. To this end, two examples demonstrating a solution of the configuration management problem are presented. In the first, a manipulator is configured that is intended for light-duty applications while in the second, several manipulators intended for medium and heavy-duty applications are configured. The analytic process developed in this work can reduce the effort in the initial phases of the design process and the total number of design iterations can be reduced.

Large deflection of constant curvature cantilever beam under follower load

2010 ◽  
Vol 52 (3) ◽  
pp. 440-445 ◽  
Author(s):  
Ashok Kumar Nallathambi ◽  
C. Lakshmana Rao ◽  
Sivakumar M. Srinivasan
Keyword(s):  
Cantilever Beam ◽  
Constant Curvature ◽  
Large Deflection ◽  
Follower Load

Stick-Slip Vibration Between Two Large Concentric Circular Discs in Rotational Contact With Multiple Point Loads

2003 ◽  
Vol 125 (4) ◽  
pp. 786-792
Author(s):  
M. Baleri ◽  
F. Sassani ◽  
P. L. Ko
Keyword(s):  
Robotic Manipulators ◽  
Integral Model ◽  
Mathematical Representation ◽  
Multiple Point ◽  
Rotating Platform ◽  
Stick Slip ◽  
System Parameters ◽  
Modeling Simulation ◽  
Contact Loads ◽  
Good Agreement

This paper presents a study of the stick-slip frictional phenomenon when large contact areas subjected to uneven contact loads, such as the rotating platform of excavators and large robotic manipulators, are involved. The objective of the investigation is to a gain better understanding of the phenomenon from experimental observations and to develop a mathematical representation that can be used for modeling, simulation and design purposes. A dynamic integral-model has been proposed and simulations have been carried out. The effects of various system parameters on the behavior of the system have been studied experimentally and analytically. The simulation results using the proposed integral-model are in good agreement with the experimental results. The latter also show that stick-slip vibrations can be influenced by the loading conditions.

scholarly journals Finding the Optimal Parameters for Robotic Manipulator Applications of the Bounded Error Algorithm for Iterative Learning Control

2017 ◽  
Vol 47 (4) ◽  
pp. 3-11 ◽  
Author(s):  
Kaloyan Yovchev
Keyword(s):  
Computer Simulation ◽  
Iterative Learning Control ◽  
Robotic Manipulators ◽  
Learning Control ◽  
Robotic Manipulator ◽  
Iterative Learning ◽  
Optimal Parameters ◽  
Manipulator Arm ◽  
Bounded Error ◽  
Optimal Values

Abstract This paper continues previous research of the Bounded Error Algorithm (BEA) for Iterative Learning Control (ILC) and its application into the control of robotic manipulators. It focuses on investigation of the influence of the parameters of BEA over the convergence rate of the ILC process. This is performed first through a computer simulation. This simulation suggests optimal values for the parameters. Afterwards, the estimated results are validated on a physical robotic manipulator arm. Also, this is one of the first reports of applying BEA into robots control.

Teaching Manipulator Kinematics by Painting With Light

2011 ◽  
Author(s):  
Michael Shomin ◽  
Jonathan Fiene
Keyword(s):  
Inverse Kinematics ◽  
Three Dimensional ◽  
Robotic Manipulators ◽  
Video Camera ◽  
Robotic Arm ◽  
End Effector ◽  
Teaching Platform ◽  
Manipulator Arm ◽  
Servo Controller ◽  
Six Degree Of Freedom

In this paper, we examine the creation and benefits of a new teaching platform to introduce and reinforce the key concepts of robotic manipulators in an introductory-level robotics course. This system combines a vintage PUMA 260 six-degree-of-freedom robotic arm with modern control circuitry and a Matlab API. The API operates as a servo controller for the robot, thereby allowing students to apply their knowledge of inverse kinematics to a real manipulator arm. To further motivate the exploration of manipulators, we have developed an open-ended project where students engage in the art of three-dimensional light painting. To facilitate this activity, a tricolor LED has been affixed to the end-effector of the robot. With a digital SLR camera, we take a long-exposure photograph as the robot is driven through a trajectory, effectively painting a picture with the end effector. We have also developed a method to quickly assemble pseudo-long-exposure photographs and videos using an inexpensive video camera. We believe this novel setup and project are an effective way to engage and motivate students to learn the underlying math and dynamics of robotic manipulators.

Large deflections of a spring-hinged tapered cantilever beam with a rotational distributed loading

1987 ◽  
Vol 91 (909) ◽  
pp. 429-437 ◽  
Author(s):  
B. Nageswara Rao ◽  
G. Venkateswara Rao
Keyword(s):  
Cantilever Beam ◽  
Cross Section ◽  
Large Deflection ◽  
Rectangular Cross Section ◽  
Large Deflections ◽  
Elastic Curves ◽  
Distributed Load ◽  
Tapered Cantilever Beam ◽  
Large Deflection Problem ◽  
Special Case

SummaryLarge deflection problem of a spring loaded hinged nonuniform cantilever beam subjected to a rotational distributed loading is formulated by means of a second-order non-linear integro-differential equation. The problem is examined by considering the beam of rectangular cross-section with linear depth taper subjected to a uniform rotational distributed load. The elastic curves of a beam for this special case are presented.

Coupled Deformations of Elastic Curves and Surfaces

2000 ◽  
Author(s):  
David Steigmann
Keyword(s):  
Three Dimensional ◽  
Finite Deformations ◽  
Rubber Elasticity ◽  
Curves And Surfaces ◽  
Elastic Curves ◽  
The Subject ◽  
Coupled Response ◽  
Structural Networks

Abstract Theories of perfectly flexible elastic curves and surfaces are frequently used to describe diverse phenomena ranging from bioelasticity and fluid capillarity to rubber elasticity and the mechanics of structural networks. It is our aim here to present a treatment of the coupled response of such continua accounting for three-dimensional interactions in the presence of finite deformations and strains. A more expansive discussion of the subject of the present paper may be found in [1].

scholarly journals Phase dependent nonlinear parametrically excited systems

2018 ◽  
Vol 25 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Bahareh Zaghari ◽  
Emiliano Rustighi ◽  
Maryam Ghandchi Tehrani
Keyword(s):  
Mathematical Model ◽  
Cantilever Beam ◽  
Phase Difference ◽  
Theoretical Understanding ◽  
Parametrically Excited ◽  
System Parameters ◽  
Energy Harvesters ◽  
Different Sources ◽  
Cubic Stiffness ◽  
Cable Stayed Bridges

Nonlinear parametrically excited (NPE) systems govern the dynamics of many engineering applications, from cable-stayed bridges where vibrations need to be suppressed, to energy harvesters, transducers and acoustic amplifiers where vibrations need to be amplified. This work investigates the effect of different system parameters on the dynamics of a prototype NPE system. The NPE system in this work is a cantilever beam with an electromagnetic subsystem excited at its base. This system allows cubic stiffness, parametric stiffness, cubic parametric stiffness, and the phase difference between different sources of excitation to be varied independently to achieve different dynamic behaviors. A mathematical model is also derived, which provides theoretical understanding of the effects of these parameters and allows the analysis to be extended to other applications.

Models of Cataclysmic Variables from Photometric and Spectroscopic Data

1979 ◽  
Vol 46 ◽  
pp. 65-74 ◽  
Author(s):  
A.C. Fabian ◽  
J.E. Pringle ◽  
J.A.J. Whelan ◽  
J.A. Bailey
Keyword(s):  
Spectroscopic Data ◽  
Cataclysmic Variables ◽  
System Parameters ◽  
Dwarf Nova ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations

Abstract.Recent photometric and spectroscopic observations of the dwarf nova system Z Cha are discussed. Methods for constraining the system parameters are applied and the disc emissivity is deduced as a function of radius. Indications are found that the disc shrinks in size with increasing time after outburst.

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