Stiffness Analysis of Delta Parallel Robots Combining the Virtual Joint Method with an FEA Stiffness Model

2018 ◽  
pp. 347-354
Author(s):  
Burkhard Corves ◽  
Christian Mirz ◽  
Jan Brinker ◽  
Daisuke Matsuura ◽  
Yukio Takeda
Keyword(s):  
Parallel Robots ◽  
Stiffness Analysis ◽  
Stiffness Model ◽  
Joint Method

Cable behavior influence on Cable-Driven Parallel Robots vibrations: experimental characterization and simulation

2021 ◽  
pp. 1-54
Author(s):  
Damien Gueners ◽  
Belhassen Chedli Bouzgarrou ◽  
Helene Chanal
Keyword(s):  
Additive Manufacturing ◽  
Tool Path ◽  
Dynamic Stiffness ◽  
Parallel Robots ◽  
Medium Size ◽  
Stiffness Analysis ◽  
Stiffness Model ◽  
Manufacturing Applications ◽  
High Level

Abstract In this paper, the influence of cable behavior, on Cable Driven Parallel Robots (CDPR) is studied. This study is conducted with the goal of designing a medium size CDPR for additive manufacturing. This robot needs to have a high level of rigidity to guarantee a given tracking tool path error. Firstly, the characterization of different thin cables (steel, Dyneema®, aramid) is presented. The mechanical properties of these cables, in terms of stiffness, damping, hysteresis and creep are compared with regard to additive manufacturing applications. A stiffness model, which takes into account the cable preload, and a dynamic model of CDPR is proposed. The simulations of these two models are compared with experimental results obtained for the range of cables studied using dynamic stiffness analysis on an 8-cable fully constrained CDPR. This paper concludes on the type of cable that should be chosen for our application.

scholarly journals Conceptual design and comparative stiffness analysis of an Exechon-like parallel kinematic machine with lockable spherical joints

2017 ◽  
Vol 14 (4) ◽  
pp. 172988141772413
Author(s):  
Teng-fei Tang ◽  
Jun Zhang
Keyword(s):  
Conceptual Design ◽  
Prediction Accuracy ◽  
Parallel Kinematic Machine ◽  
Stiffness Analysis ◽  
Parallel Kinematic Machines ◽  
Stiffness Model ◽  
Dynamic Analyses ◽  
Parallel Kinematic ◽  
Kinetostatic Model ◽  
Limb Structure

This article proposes two types of lockable spherical joints which can perform three different motion patters by locking or unlocking corresponding rotational axes. Based on the proposed lockable spherical joints, a general reconfigurable limb structure with two passive joints is designed with which the conceptual designs of two types of Exechon-like parallel kinematic machines are completed. To evaluate the stiffness of the proposed Exechon-like parallel kinematic machines, an expanded kinetostatic model is established by including the compliances of all joints and limb structures. The prediction accuracy of the expanded stiffness model is validated by numerical simulations. The comparative stiffness analyses prove that the Exe-Variant parallel kinematic machine claims competitive rigidity performance to the Exechon parallel kinematic machine. The present work can provide useful information for further investigations on structural enhancement, rigidity improvement, and dynamic analyses of other Exechon-like parallel kinematic machines.

Kineto Static Design and Stiffness Analysis of a New Kind of 3-RRR Planar Parallel Manipulator

2014 ◽  
Vol 592-594 ◽  
pp. 2303-2307
Author(s):  
M. Ganesh ◽  
R. Karthikeyan ◽  
Anjan Kumar Dash ◽  
M. Vikramadityan ◽  
R. Gopalachary
Keyword(s):  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Moment Of Inertia ◽  
Stiffness Analysis ◽  
Stiffness Model ◽  
Planar Parallel Manipulator ◽  
The Moment

This paper presents a new design of a 3-RRR planar manipulator with non-planar legs. In contrast to the conventional 3-RRR planar parallel mechanism, the links are not planar. They are elevated above the X-Y plane and non planar legs are constructed. The kinematics of this model is realized on a common projected plane and traced back to its elevated position. The moment of inertia for the inclined links is computed. A stiffness model is established for the proposed design of 3-RRR manipulator and compared with a conventional 3-RRR planar manipulator. The analysis shows how the proposed design has better stiffness along all the three directions of motion.

Nonlinear Stiffness Analysis of Spring-Loaded Inverted Slider Crank Mechanisms With a Unified Model

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Zhongyi Li ◽  
Shaoping Bai ◽  
Weihai Chen ◽  
Jianbin Zhang
Keyword(s):  
Variable Stiffness ◽  
Comprehensive Analysis ◽  
Unified Model ◽  
Nonlinear Stiffness ◽  
Stiffness Analysis ◽  
Constant Torque ◽  
Stiffness Model ◽  
Overall Performance ◽  
Crank Mechanism

Abstract A mechanism with lumped-compliance can be constructed by mounting springs at joints of an inverted slider crank mechanism. Different mounting schemes bring change in the stiffness performance. In this paper, a unified stiffness model is developed for a comprehensive analysis of the stiffness performance for mechanisms constructed with different spring mounting schemes. With the model, stiffness behaviors of spring-loaded inverted slider crank mechanisms are analyzed. Influences of each individual spring on the overall performance are characterized. The unified stiffness model allows designing mechanisms for a desired stiffness performance, such as constant-torque mechanism and variable stiffness mechanism, both being illustrated with a design example and experiments.

Stiffness Analysis of a Tripod With a Passive Link

2005 ◽  
Author(s):  
Z. M. Bi ◽  
S. Y. T. Lang ◽  
D. Zhang
Keyword(s):  
Constrained Motion ◽  
Motion Platform ◽  
Stiffness Analysis ◽  
Stiffness Model ◽  
Parallel Kinematic Mechanism ◽  
Parallel Kinematic ◽  
Linear Actuators ◽  
Main Components ◽  
Kinematic Mechanism

The system stiffness of a tripod parallel kinematic mechanism (PKM) with 3-DOF is investigated in this paper. The tripod PKM has rotations of a motion platform about the x and y axes and translation along the z axis. The motion on the other axes is constrained by a passive link. The stiffness model considers the compliances of three main components: the fixed-length links, the passive link, and the linear actuators. The modeling procedure for the kinetostatic stiffness model is introduced. A case study is provided to demonstrate evaluation of the stiffness of our prototype tripod machine. The developed model differs from the others in the sense that the stiffness on the motion axes is determined by both the active links and the passive link; but the stiffness on the constrained motion axes depends merely on the passive link.

Analysis and Optimal Design for the Static Stiffness of a 2UPS-UPR Parallel Machine Tool

2009 ◽  
Vol 626-627 ◽  
pp. 429-434 ◽  
Author(s):  
Liang Zhao ◽  
Ya Dong Gong ◽  
Guang Qi Cai
Keyword(s):  
Machine Tool ◽  
Structural Design ◽  
Machine Tools ◽  
Structural Parameters ◽  
Parallel Machine ◽  
Static Stiffness ◽  
Stiffness Analysis ◽  
Stiffness Model ◽  
Parallel Machine Tool ◽  
Stiffness Distribution

The stiffness model of the parallel machine tool is established by static analysis, the static stiffness analysis is carried out through numerical Simulation and the stiffness distribution is given. On the basis of this, the optimal objective is given which is the average of 729 values of -axis stiffness and -axis stiffness corresponding to 729 positions in the workspace. With MATLAB software, the effects are simulated which the structural parameters of the parallel machine tool have on their stiffness, their change rules are gained, and this provides a basis for the structural design of this type of machine tools.

Static Stiffness Analysis of a Novel Parallel Manipulator

2012 ◽  
Vol 522 ◽  
pp. 703-707
Author(s):  
Yun Feng Li ◽  
Chang Feng Li ◽  
Dong Sheng Qu ◽  
Ling Zou
Keyword(s):  
Parallel Manipulator ◽  
Virtual Work ◽  
Elastic Model ◽  
Static Stiffness ◽  
Single Chain ◽  
Stiffness Analysis ◽  
Stiffness Properties ◽  
Maximum Stiffness ◽  
Stiffness Model ◽  
Spatial Architecture

One novel 6-DOF parallel manipulator with hooke hinges is presented to provide precision positioning in this paper. The geometric parameters and spatial architecture of kinematic pairs will influence the system stiffness directly, which impact indirectly the characteristics such as supporting capacity, driving burden and so on. The elastic model of the single chain based on the stiffness equation is presented and the stiffness model of the whole structure is constructed via the principle of virtual work. The static stiffness properties of the manipulator are discussed and the problem of finding the minimum and maximum stiffness and the directions in which they occur for a manipulator in a given posture is addressed. An example is given and the results show that static stiffness properties can be used to guide the optimal design of the structure.

A Non-Linear Stiffness Model for Serial and Parallel Manipulators

2017 ◽  
Vol 5 (1) ◽  
pp. 34-62
Author(s):  
Manoj Kumar
Keyword(s):  
Numerical Technique ◽  
Sudden Change ◽  
Parallel Manipulators ◽  
Rigid Bodies ◽  
Stiffness Analysis ◽  
Cartesian Stiffness Matrix ◽  
Stiffness Model ◽  
Non Linear ◽  
Linear Behaviour ◽  
Cartesian Stiffness

The paper presents a methodology to enhance the stiffness analysis of serial and parallel manipulators with passive joints. It directly takes into account the loading influence on the manipulator configuration and, consequently, on its Jacobians and Hessians. The main contributions of this paper are the introduction of a non-linear stiffness model for the manipulators with passive joints, a relevant numerical technique for its linearization and computing of the Cartesian stiffness matrix which allows rank-deficiency. Within the developed technique, the manipulator elements are presented as pseudo-rigid bodies separated by multidimensional virtual springs and perfect passive joints. Simulation examples are presented that deal with parallel manipulators of the Ortholide family and demonstrate the ability of the developed methodology to describe non-linear behaviour of the manipulator structure such as a sudden change of the elastic instability properties (buckling).

Experimental Structural Stiffness Analysis of a Surgical Haptic Master Device Manipulator

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
İbrahimcan Görgülü ◽  
Mehmet İsmet Can Dede ◽  
Giuseppe Carbone
Keyword(s):  
Model Fitting ◽  
Experimental Results ◽  
Fine Tuning ◽  
Structural Stiffness ◽  
Stiffness Analysis ◽  
Stiffness Model ◽  
Stiffness Evaluation ◽  
Institute Of Technology ◽  
Master Device

Abstract This paper deals with haptic devices for master–slave telesurgical applications. Namely, a stiffness model fitting methodology and its fine-tuning are proposed based on experimental results. In particular, the proposed procedure is based on virtual joint structural stiffness modeling to be applied in time-efficient compliance compensation strategies. A specific case study is discussed by referring to the HISS haptic device that has been developed and built at Izmir Institute of Technology. Two different experimental setups are designed for stiffness evaluation tests. Experimental results are discussed to demonstrate their implementation in the proposed methodology for the fine-tuning of stiffness model.

Stiffness Analysis for a Novel Parallel-Robot Based High-Precision Flexible Assembly Fixture

2007 ◽  
Vol 364-366 ◽  
pp. 327-332 ◽  
Author(s):  
Hong Jian Yu ◽  
Bing Li ◽  
Xiao Jun Yang ◽  
Ying Hu ◽  
Hong Hu
Keyword(s):  
Stiffness Matrix ◽  
Screw Theory ◽  
System Modeling ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Stiffness Analysis ◽  
Flexible Assembly ◽  
Global Stiffness Matrix ◽  
The Relationship ◽  
Assembly Fixture

In this paper, a novel parallel mechanism (3-RRRS/UPR) used in flexible fixture with configuration composed of two parallel robots (2-RR and 3-RRRS/ UPR) is presented. First, system modeling including the mobility study is conducted. Then a novel methodology is proposed that makes use of screw theory to analyze the deformation and stiffness of the mechanism: firstly we identified the existence of the deformation of the subchain, in terms of the relationship between the effective screw and deformation screw; then we took the deformation as an infinitesimal motion of the mechanism, and the stiffness matrix corresponding to the deformation can be deduced. Finally the global stiffness matrix of the whole mechanism is modeled by assembling different stiffness characters based on the presented methodology.

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