scholarly journals PZT Actuators’ Effect on Vibration Control of the PRRRP 2-DOF Flexible Parallel Manipulator

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Amin Valizadeh ◽  
Morteza Shariatee
Keyword(s):  
Vibration Control ◽  
Parallel Manipulator ◽  
Dynamic Properties ◽  
Kinematic Modeling ◽  
Lagrange Equations ◽  
Assumed Mode Method ◽  
Planar Parallel Manipulator ◽  
Mode Method ◽  
Simplifying Assumptions ◽  
Flexible Behavior

Thanks to their advantages over rigid ones, interest for lightweight parallel manipulator was increased. Besides, structural flexibility effects at high operational speeds are more significant. Thus, developing an appropriate model for the assessment of the dynamic properties of flexible mechanisms and linkages to gain effective vibration control will raise high demand. Therefore, this paper represents the dynamic and kinematic modeling using the assumed mode method and first-type Lagrange equations of the 2-DOF planar parallel manipulator with two flexible links. To truly predict vibrations of the manipulator without any major simplifying assumptions, nonlinear dynamic modeling, which thoroughly attempts to represent the flexible behavior of the links, is considered. As a result, an active damping approach is being studied with PZT actuators. The results show that this approach is effective in damping the vibrations of the links that give accurate trajectory control.

Investigation of axial forces on dynamic properties of a flexible 3-PRR planar parallel manipulator moving with high speed

Robotica ◽  
2009 ◽  
Vol 28 (4) ◽  
pp. 607-619 ◽  
Author(s):  
Xuping Zhang ◽  
James K. Mills ◽  
William L. Cleghorn
Keyword(s):  
Parallel Manipulator ◽  
High Speed ◽  
Dynamic Properties ◽  
Parallel Manipulators ◽  
Body Motion ◽  
Valuable Insight ◽  
Bending Vibration ◽  
Assumed Mode Method ◽  
Axial Forces ◽  
Planar Parallel Manipulator

SUMMARYThe effect of axial forces on the dynamic properties is formulated and investigated for a 3-PRR planar parallel manipulator with three flexible intermediate links. A dynamic model of the manipulator system is developed based on the assumed mode method with the consideration of the effect of longitudinal forces on lateral stiffness is included. The flexible intermediate links are modeled as Euler–Bernoulli beams with pinned-pinned boundary conditions, which are verified by experimental modal tests. Natural frequencies of bending vibration of the intermediate links are derived as the functions of axial force and rigid-body motion of the manipulator. Dynamic behavior including the effect of axial forces on lateral deformation is investigated, and configuration-dependant frequencies are analyzed. Numerical simulations of configuration-dependent frequency properties and axial forces are performed to illustrate the effect of axial forces on the dynamic behaviors of the flexible parallel manipulator. Simulation results of mode amplitudes, deformations, axial forces, inertial, and coupling forces are presented, and further validate the theoretical derivations. These analyses and results provide a new and valuable insight to the design and control of the parallel manipulators with flexible intermediate links.

Structural Vibration Control of a Moving 3-PRR Flexible Parallel Manipulator With Multiple PZT Actuators and Sensors

2007 ◽  
Author(s):  
Xuping Zhang ◽  
James K. Mills ◽  
William L. Cleghorn
Keyword(s):  
Vibration Control ◽  
Lead Zirconate Titanate ◽  
Control Strategy ◽  
Parallel Manipulator ◽  
Active Vibration Control ◽  
Structural Vibration ◽  
Structural Vibrations ◽  
Frequency Spectra ◽  
Pzt Actuator ◽  
Assumed Mode Method

This paper addresses the control of structural vibrations of a 3-PRR parallel manipulator with three flexible intermediate links, bonded with multiple lead zirconate titanate (PZT) actuators and sensors. Flexible intermediate links are modeled as Euler-Bernoulli beams with pinned-pinned boundary conditions. A PZT actuator controller is designed based on strain rate feed control (SRF). Control moments from PZT actuators are transformed to force vectors in modal space, and are incorporated in the dynamic model of the manipulator. The dynamic equations are developed based on the assumed mode method for the flexible parallel manipulator with multiple PZT actuator and sensor patches. Numerical simulation is performed and the results indicate that the proposed active vibration control strategy is effective. Frequency spectra analyses of structural vibrations further illustrate that deformations from structural vibration of flexible links are suppressed to a significant extent when the proposed vibration control strategy is employed, while the deflections caused by inertial and coupling forces are not reduced.

Vibration control of elastodynamic response of a 3-PRR flexible parallel manipulator using PZT transducers

Robotica ◽  
2008 ◽  
Vol 26 (5) ◽  
pp. 655-665 ◽  
Author(s):  
Xuping Zhang ◽  
James K. Mills ◽  
William L. Cleghorn
Keyword(s):  
Vibration Control ◽  
Lead Zirconate Titanate ◽  
Control Strategy ◽  
Parallel Manipulator ◽  
Active Vibration Control ◽  
Lead Zirconate ◽  
Structural Vibration ◽  
Structural Vibrations ◽  
Pzt Actuator ◽  
Assumed Mode Method

SUMMARYThis paper addresses the dynamic simulation and control of structural vibrations of a 3-PRR parallel manipulator with three flexible intermediate links, to which are bonded lead zirconate titanate (PZT) actuators and sensors. Flexible intermediate links are modelled as Euler–Bernoulli beams with pinned-pinned boundary conditions. A PZT actuator controller is designed based on strain rate feedback (SRF) control. Control moments from PZT actuators are transformed to force vectors in modal space and are incorporated in the dynamic model of the manipulator. The dynamic equations are developed based on the assumed mode method for the flexible parallel manipulator with multiple PZT actuator and sensor patches. Numerical simulation is performed and the results indicate that the proposed active vibration control strategy is effective. Spectral analyses of structural vibrations further illustrate that deformations from structural vibration of flexible links are suppressed to a significant extent when the proposed vibration control strategy is employed, while the deflections caused by inertial and coupling forces are not reduced.

Dynamic Modeling of Cable-Driven Parallel Manipulators With Distributed Mass Flexible Cables

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Jingli Du ◽  
Sunil K. Agrawal
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Equation ◽  
Parallel Manipulator ◽  
Dynamic Models ◽  
Parallel Manipulators ◽  
Assumed Mode Method ◽  
Mode Method ◽  
Algebraic Constraints ◽  
Flexible Cables ◽  
Assumed Mode

A cable-driven parallel manipulator is an economic way to achieve manipulation over large workspace. However, unavoidable vibration in long cables can dramatically degenerate the positioning performance of manipulators. In this paper, dynamic models of large cable-driven parallel manipulators (CDPMs) are addressed where each cable is considered with distributed mass and can change in length during operation. The dynamic equation of a cable deployed or retrieved is derived using Hamilton's principle. The dynamic model of the system is characterized by partial differential equations with algebraic constraints. By properly selecting the independent unknowns, we solve the model using assumed-mode method.

Dynamic characteristics of a 3-RPR planar parallel manipulator with flexible intermediate links

Robotica ◽  
2014 ◽  
Vol 33 (9) ◽  
pp. 1909-1925 ◽  
Author(s):  
Amirhossein Eshaghiyeh Firoozabadi ◽  
Saeed Ebrahimi ◽  
Ghasem Amirian
Keyword(s):  
Boundary Conditions ◽  
Dynamic Modeling ◽  
Parallel Manipulator ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
End Effector ◽  
Assumed Mode Method ◽  
Planar Parallel Manipulator

SUMMARYThis paper presents the dynamic modeling of a 3-RPR planar parallel manipulator with three flexible intermediate links in order to investigate the effects of the intermediate links flexibility on the undesired vibrations of the end-effector. For this purpose, the intermediate links are modeled as Euler--Bernoulli beams with two types of fixed-pinned and fixed-free boundary conditions based on the assumed mode method (AMM). The equations of motion of the 3-RPR manipulator are formulated using the augmented Lagrange multipliers method in the form of differential algebraic equations (DAEs) by incorporating the elastic and rigid coordinates in the set of generalized coordinates. After defining the initial conditions and imposing external forces to the manipulator, the equations are then solved numerically using the Modified Extended Backward-Differentiation Formula Implicit (MEBDFI) approach. Comparison of the simulation results for two different boundary conditions shows clearly the effects of flexibility of the intermediate links on the vibration of the end-effector trajectory. Results of this work can be used for the dynamic modeling of other manipulators or to design a controller for reducing the undesired vibrations.

scholarly journals Internal redundancy: an approach to improve the dynamic parameters around sharp corners

2013 ◽  
Vol 4 (1) ◽  
pp. 233-242 ◽  
Author(s):  
S. S. Parsa ◽  
J. A. Carretero ◽  
R. Boudreau
Keyword(s):  
Parallel Manipulator ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Parallel Manipulators ◽  
Variable Geometry ◽  
Centre Of Mass ◽  
Serial Manipulators ◽  
Singular Configurations ◽  
Planar Parallel Manipulator ◽  
Sharp Corners

Abstract. In recent years, redundancy in parallel manipulators has been studied broadly due to its capability of overcoming some of the drawbacks of parallel manipulators including small workspaces and singular configurations. Internal redundancy, first introduced for serial manipulators, refers to the concept of adding movable masses to some links so as to allow to control the location of the centre of mass and other dynamic properties of some links. This concept has also been referred to as variable geometry. This paper investigates the effects of internal redundancy on the dynamic properties of a planar parallel manipulator while performing a family of trajectories. More specifically, the 3-RRR planar manipulator, where a movable mass has been added to the distal link, is allowed to trace trajectories with rounded corners and different radii. The proposed method uses the manipulator's dynamic model to actively optimise the location of the redundant masses at every point along the trajectory to improve the dynamic performance of the manipulator. Numerical examples are shown to support the idea.

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