Design of a nonlinear absorber for a 2 degrees of freedom pendulum and experimental validation

2021 ◽  
Author(s):  
Gabriel Hurel ◽  
Alireza Ture Savadkoohi ◽  
Claude‐Henri Lamarque
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Nonlinear Absorber

Experimental Validation of the Kinematics of a 3PRS Compliant Mechanism for Micromilling

2015 ◽  
Author(s):  
Antonio Ruiz ◽  
Francisco Campa Gomez ◽  
Constantino Roldan-Paraponiaris ◽  
Oscar Altuzarra
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Compliant Mechanism ◽  
Motion Controller ◽  
End Effector ◽  
Compliant Joints ◽  
Hybrid Manipulator ◽  
Compliant Parallel Mechanism ◽  
Actuated Joints

The present work deals with the development of a hybrid manipulator of 5 degrees of freedom for milling moulds for microlenses. The manipulator is based on a XY stage under a 3PRS compliant parallel mechanism. The mechanism takes advantage of the compliant joints to achieve higher repetitiveness, smoother motion and a higher bandwidth, due to the high precision demanded from the process, under 0.1 micrometers. This work is focused on the kinematics of the compliant stage of the hybrid manipulator. First, an analysis of the workspace required for the milling of a single mould has been performed, calculating the displacements required in X, Y, Z axis as well as two relative rotations between the tool and the workpiece from a programmed toolpath. Then, the 3PRS compliant parallel mechanism has been designed using FEM with the objective of being stiff enough to support the cutting forces from the micromilling, but flexible enough in the revolution and spherical compliant joints to provide the displacements needed. Finally, a prototype of the 3PRS compliant mechanism has been built, implementing a motion controller to perform translations in Z direction and two rotations. The resulting displacements in the end effector and the actuated joints have been measured and compared with the FEM calculations and with the rigid body kinematics of the 3PRS.

Numerical and experimental performance estimation for a ExoFing - 2 DOFs finger exoskeleton

Robotica ◽  
2021 ◽  
pp. 1-13
Author(s):  
G Carbone ◽  
M Ceccarelli ◽  
C. E. Capalbo ◽  
G Caroleo ◽  
C Morales-Cruz
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Index Finger ◽  
Kinematic Model ◽  
Experimental Tests ◽  
Performance Estimation ◽  
Experimental Performance ◽  
Finger Motion ◽  
User Friendly ◽  
Operation Characteristics

Abstract This paper presents a numerical and experimental validation of ExoFing, a two-degrees-of-freedom finger mechanism exoskeleton. The main functionalities of this device are investigated by focusing on its kinematic model and by computing its main operation characteristics via numerical simulations. Experimental tests are designed and carried out for validating both the engineering feasibility and effectiveness of the ExoFing system aiming at achieving a human index finger motion assistance with cost-oriented and user-friendly features.

Kinematics, Workspace Optimization, and Performance Evaluation of a 3-Leg 6-DOF Robot in RRRS Configuration

2020 ◽  
Author(s):  
Nathan A. Jensen ◽  
Carl A. Nelson
Keyword(s):  
Performance Evaluation ◽  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Inverse Kinematic ◽  
And Performance ◽  
Workspace Optimization ◽  
Optimization And Performance

Abstract Underactuated parallel manipulators that achieve 6 DOF via multiple controllable degrees of freedom per leg are often pursued and reported due to their large workspaces. This benefit comes at a cost to the manipulator’s performance, however. Such manipulators must then be evaluated in order to characterize their kinematics in terms of position and motion. This paper establishes a pair of inverse kinematic solutions for a previously proposed and prototyped 3-leg, 6-DOF parallel robot. These solutions are then used to define the robot’s workspace with experimental validation and to optimize the robot’s geometry for maximum workspace volume. The linear components of the Jacobian are then defined, allowing for analysis of the manipulability of the robot. The full Jacobian is also defined, and singularities are examined throughout the workspace of the robot.

Study of an electromechanical nonlinear vibration absorber: Design via analytical approach

2020 ◽  
pp. 1045389X2095710
Author(s):  
Vinciane Guillot ◽  
Alireza Ture Savadkoohi ◽  
Claude-Henri Lamarque
Keyword(s):  
Degrees Of Freedom ◽  
Mechanical Response ◽  
Electrical Circuit ◽  
Vibration Absorber ◽  
Cubic Nonlinearity ◽  
Analytical Treatment ◽  
Nonlinear Absorber ◽  
Definition Of ◽  
Direct Numerical Integration ◽  
Two Degree Of Freedom

This article deals with the behavior and design of a homogeneous beam linked to an electrical absorber, via a piezoelectric material patched on the beam. The beam presents a cubic nonlinearity, which is consistent with geometrical nonlinearities for clamped-free beams. A cubic nonlinearity is added to the electrical circuit for similarity purposes. The coupled electromechanical equations are reduced to a two degrees of freedom system. The equation representing the mechanical response of the system is seen as the main system, whereas the equation coming from the electrical circuit would represent a nonlinear absorber. An analytical treatment at different time scales is endowed to identify electrical coefficients allowing the design of the electromechanical vibration absorber behavior. The equilibrium and singular points are identified, allowing the definition of ranges of forcing amplitudes leading to periodic and modulated regimes. The analytical results are compared with those obtained from direct numerical integration of the two degree of freedom system.

Experimental validation of a 2 degrees of freedom whisker sensor dynamic model

2011 ◽  
Vol 44 (1) ◽  
pp. 3148-3152 ◽  
Author(s):  
Claudia F Castillo-Berrio ◽  
Vicente Feliu Batlle ◽  
Fernando J Castillo-Garcia
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Experimental Validation

scholarly journals Design and Prototyping of a Partially Decoupled 4-DOF 3T1R Parallel Manipulator With High-Load Carrying Capacity

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Sébastien Briot ◽  
Vigen Arakelian ◽  
Sylvain Guégan
Keyword(s):  
Carrying Capacity ◽  
Horizontal Plane ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Vertical Axis ◽  
High Load ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Fixed Orientation

In this paper, a new four degrees of freedom 3T1R parallel manipulator with high-load carrying capacity is presented. This manipulator generates Schönflies motions, in which the moving platform carries out three independent translations and one rotation about one axis of fixed orientation. The particularity of the proposed architecture is the decoupling of the displacements of the platform in the horizontal plane from the platform’s translation along the vertical axis. Such a decoupling allows the cancellation of the gravity loads on the actuators, which displace the platform in the horizontal plane. A prototype of the proposed manipulator with four degrees of freedom and an experimental validation of the suggested concept are also presented. Two cases have been examined on the built prototype: a manipulator with payload and one without. It was shown that the input torques of actuators displacing the platform in the horizontal plane for these two cases are the same; i.e., the payload does not bring any load to the actuators.

Two degrees of freedom PID multi-controllers to design a mathematical driver model: experimental validation and robustness tests

2011 ◽  
Vol 49 (4) ◽  
pp. 595-624 ◽  
Author(s):  
Lghani Menhour ◽  
Daniel Lechner ◽  
Ali Charara
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Driver Model ◽  
Two Degrees Of Freedom

scholarly journals Multi-Axial Hybrid Fire Testing based on Dynamic Relaxation

2021 ◽  
Author(s):  
Nikolaos Tsokanas ◽  
Giuseppe Abbiati ◽  
Konstantinos Kanellopoulos ◽  
Bozidar Stojadinovic
Keyword(s):  
Hybrid Model ◽  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Technical Note ◽  
Static Response ◽  
Fire Testing ◽  
Dynamic Relaxation ◽  
Multiple Degrees Of Freedom ◽  
First Time

This technical note presents the experimental validation of a hybrid fire testing coordination algorithm recently developed by some of the authors. For the first time, the algorithm is applied to solve the static response of a multiple-degrees-of-freedom hybrid model.

scholarly journals Dynamics of on-board rotors on finite-length journal bearings subject to multi-axial and multi-frequency excitations: numerical and experimental investigations

2021 ◽  
Vol 22 ◽  
pp. 35
Author(s):  
Yvon Briend ◽  
Eric Chatelet ◽  
Régis Dufour ◽  
Marie-Ange Andrianoely ◽  
Franck Legrand ◽  
...  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Parametric Instability ◽  
Experimental Investigations ◽  
Element Formulation ◽  
Hydrodynamic Bearing ◽  
Mass Unbalance ◽  
Moving Base ◽  
Technology Applications

On-board rotating machinery subject to multi-axial excitations is encountered in a wide variety of high-technology applications. Such excitations combined with mass unbalance forces play a considerable role in their integrity because they can cause parametric instability and rotor–stator interactions. Consequently, predicting the rotordynamics of such machines is crucial to avoid triggering undesirable phenomena or at least limiting their impacts. In this context, the present paper proposes an experimental validation of a numerical model of a rotor-shaft-hydrodynamic bearings system mounted on a moving base. The model is based on a finite element approach with Timoshenko beam elements having six degrees of freedom (DOF) per node to account for the bending, torsion and axial motions. Classical 2D rectangular finite elements are also employed to obtain the pressure field acting inside the hydrodynamic bearing. The finite element formulation is based on a variational inequality approach leading to the Reynolds boundary conditions. The experimental validation of the model is carried out with a rotor test rig, designed, built, instrumented and mounted on a 6-DOF hydraulic shaker. The rotor’s dynamic behavior in bending, torsion and axial motions is assessed with base motions consisting of mono- and multi-axial translations and rotations with harmonic, random and chirp sine profiles. The comparison of the predicted and measured results achieved in terms of shaft orbits, full spectrums, transient history responses and power spectral densities is very satisfactory, permitting the experimental validation of the model proposed.

Sign in / Sign up

Export Citation Format

Share Document