Dynamic modeling and performance evaluation of a 2UPR-PRU parallel kinematic machine based on screw theory

2021 ◽  
Author(s):  
Chenyang Rao ◽  
Lingmin Xu ◽  
Qiaohong Chen ◽  
Wei Ye
Keyword(s):  
Performance Evaluation ◽  
Dynamic Modeling ◽  
Screw Theory ◽  
Parallel Kinematic Machine ◽  
Parallel Kinematic ◽  
And Performance

scholarly journals Performance Evaluation of Redundant Parallel Manipulators Assimilating Motion/Force Transmissibility

10.5772/50904 ◽  
2011 ◽  
Vol 8 (5) ◽  
pp. 66 ◽  
Author(s):  
Fugui Xie ◽  
Xin-Jun Liu ◽  
Jinsong Wang
Keyword(s):  
Performance Evaluation ◽  
Parallel Manipulators ◽  
Important Class ◽  
Optimization Strategy ◽  
Kinematic Redundancy ◽  
Inverse Solutions ◽  
Force Transmissibility ◽  
Parallel Kinematic ◽  
And Performance

Performance evaluation is one of the most important issues in the field of parallel kinematic manipulators (PKMs). As a very important class of PKMs, the redundant PKMs have been studied intensively. However, the performance evaluation of this type of PKMs is still unresolved and a challenging endeavor. In this paper, indices that assimilate motion/force transmissibility are proposed to evaluate the performance of redundant PKMs. To illustrate the application of these indices, three PKMs with different kinds of redundancies are taken as examples, and performance atlases are plotted based on the definitions of the indices. Transmissibility comparisons between redundant PKMs and the corresponding non-redundant ones are carried out. To determine the inverse solutions of the PKMs with kinematic redundancy, an optimization strategy is presented, and the rationality of this method is demonstrated. The indices introduced here can be applied to the performance evaluation of redundant parallel manipulators.

A modified elasto-dynamic model based static stiffness evaluation for a 3-PRS PKM

2015 ◽  
Vol 230 (3) ◽  
pp. 353-366 ◽  
Author(s):  
Yan-Qin Zhao ◽  
Jun Zhang ◽  
Ling-Yan Ruan ◽  
Hai-Wei Luo ◽  
Xiao-Liu Yu
Keyword(s):  
Dynamic Model ◽  
Stiffness Matrix ◽  
Performance Enhancement ◽  
Element Formulation ◽  
Parallel Kinematic Machine ◽  
Design Variables ◽  
Parallel Kinematic ◽  
And Performance ◽  
Global Stiffness Matrix ◽  
Spring Constants

This paper proposes a modified elasto-dynamic model for a three-prismatic revolute spherical parallel kinematic machine, in which the flexibility of the prismatic revolute spherical limb structures are accounted in and modeled as a hollowed spatial beam with nonuniform cross section. The governing equations are derived through substructure synthesis and finite element formulation. The stiffness matrix of the platform is then extracted from global stiffness matrix and its characteristics at typical configurations are calculated to reveal complicated coupling effects of diagonal and nondiagonal elements of the stiffness matrix. The concept of principle stiffness and coupled stiffness are proposed and their distributions over the workspace are predicted with numerical simulations in a quick manner. Then the stiffness of the platform is physically interpreted as a kinematically unconstrained rigid body suspended by six screw springs with equivalent spring constants and pitches through eigenscrew decomposition. The distributions of screw spring constants over the workspace are then plotted to demonstrate a duality property. At last, the effects of some design variables such as structural and dimensional parameters on system rigidity performance are investigated with the purpose of providing useful information for the structural design and performance enhancement of the parallel kinematic machine.

Dynamic Modeling and Performance Evaluation of a Vibrating Cantilever Beam Microgyroscope

2005 ◽  
Author(s):  
Mehdi Esmaeili ◽  
Mohammad Durali ◽  
Nader Jalili
Keyword(s):  
Performance Evaluation ◽  
Dynamic Modeling ◽  
Input Parameter ◽  
Galerkin Approximation ◽  
Linear Functions ◽  
System Sensitivity ◽  
Beam Displacement ◽  
Overall Performance ◽  
And Performance ◽  
Tip Mass

This paper discusses the effects of substrate motions on the performance of microgyroscopes modeled as suspended beams with a tip mass. The substrate movements can be motions along as well as rotations around the three axes. Using Extended Hamiltonian Principle and Galerkin approximation, the equations of the motion of the beam are analytically derived. In these equations, the effects of beam distributed mass, tip mass, angular accelerations, centripetal and coriolis accelerations are clearly apparent. The effect of electrostatic forces inducing the excitation vibrations are considered as linear functions of beam displacement. The response of the system to different inputs is studied and the system sensitivity to input parameter changes are examined. Finally, the sources of error in the measurement of rotation rate input are recognized. The study demonstrated the importance of errors caused by cross axes inputs on the gyroscope output measurements and overall performance.

Hybrid-model-based stiffness analysis of a three-revolute-prismatic-spherical parallel kinematic machine

2016 ◽  
Vol 231 (14) ◽  
pp. 2561-2576 ◽  
Author(s):  
Jun Zhang ◽  
Yan Q Zhao ◽  
Hai W Luo
Keyword(s):  
High Speed ◽  
Experimental Tests ◽  
Design Parameters ◽  
Parallel Kinematic Machine ◽  
Modeling Methodology ◽  
Parallel Kinematic ◽  
Stiffness Characteristics ◽  
And Performance ◽  
High Dynamics ◽  
Spring Constants

A three-revolute-prismatic-spherical parallel kinematic machine is proposed as an alternative solution for high-speed machining tool due to its high rigidity and high dynamics. Considering the parallel kinematic machine module as a typical compliant parallel mechanism, whose three limb assemblages have bending, extending and torsional deflections, this article proposes a hybrid modeling methodology to establish an analytical stiffness model for the three-revolute-prismatic-spherical device. The developed analytical model is further used to evaluate the stiffness mapping of the three-revolute-prismatic-spherical module over a given work plane which is then validated by experimental tests. The simulations and experiments indicate that the present hybrid methodology can predict the three-revolute-prismatic-spherical parallel kinematic machine’s stiffness in a quick and accurate manner. The solution for eigenvalue problem of the stiffness matrix leads to the stiffness characteristics of the parallel module including eigenstiffnesses and the corresponding eigenscrews as well as the equivalent screw spring constants. Based on the eigenscrew decomposition, the parallel kinematic machine is physically interpreted as a rigid platform suspending by six screw springs. The minimum, maximum and average of the screw spring constants are chosen as indices to assess the three-revolute-prismatic-spherical parallel kinematic machine’s stiffness performance. The distributions of the proposed indices throughout the workspace reveal a strong dependency on the mechanism’s configurations. At the final stage, the effects of some design parameters on system stiffness characteristics are investigated with the purpose of providing useful information for the conceptual design and performance improvement of the parallel kinematic machine.

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