A Novel Iterative Method of Determining the Pose Error of Planar Clearance-Affected Flexible Parallel Mechanisms Under Loaded Mode

2020 ◽  
Author(s):  
Qiangqiang Zhao ◽  
Junkang Guo ◽  
Jun Hong
Keyword(s):  
Iterative Method ◽  
Iterative Scheme ◽  
Virtual Work ◽  
Parallel Mechanisms ◽  
Single Chain ◽  
Linear Superposition ◽  
Equilibrium Conditions ◽  
Virtual Work Principle ◽  
Taylor Series Approximation ◽  
Flexible Model

Abstract Clearance and flexibility play an essential role in determining the accuracy of a planar parallel mechanism. However, previous accuracy prediction methods either considered only one of them or combined them in linear superposition. Therefore, this study proposes a novel iterative method for determining the pose error by considering clearance and flexibility simultaneously. First, the rigid-flexible model of the mechanism with clearances is developed based on the virtual joint method, in which the equilibrium conditions under the external load are established via the virtual work principle and differential forward kinematics. Then, using a Taylor series approximation, the “instant” stiffness matrix corresponding to a specific load is deduced. On this basis, an iterative scheme is explored to search for the final equilibrium pose, in which a child iterative scheme is constructed to determine the joint variables and suffered wrench of the single chain given a pose. Finally, the developed method is demonstrated by calculating the comparative pose errors of the planar five-bar mechanism and 3-RPR robot.

Servomotor Parameter Estimation of a 2-DOF Translations and Full Rotation Parallel Mechanism

2010 ◽  
Vol 139-141 ◽  
pp. 2140-2145
Author(s):  
Yan Bing Ni ◽  
Xue Yong Zhong ◽  
Lei Guo ◽  
Fa Yang Luo
Keyword(s):  
Parallel Mechanism ◽  
Prediction Models ◽  
Virtual Work ◽  
Maximum Velocity ◽  
Singular Value ◽  
Parallel Mechanisms ◽  
Inverse Dynamic ◽  
Virtual Work Principle ◽  
Full Rotation ◽  
Value Decomposition

Considering the need of designing a parallel mechanism which can achieve a whole week of rotation and two translations, in this paper, the inverse dynamic model based on the virtual work principle was established. And because the maximum velocity and torque of servomotor are the key indices to choose the servomotor, the prediction models of the maximum velocity and torque of active joints employing the singular value decomposition technique were established as well; further, the prediction model of moment of inertia of servomotor was proposed, and then the computer simulation which can the indentify the effectiveness of this method was conducted. The estimating method has been successfully applied in the series of the parallel mechanisms.

A PD Computed Torque Control Method with Online Self-gain Tuning for a 3UPS-PS Parallel Robot

Robotica ◽  
2021 ◽  
pp. 1-13
Author(s):  
Xiaogang Song ◽  
Yongjie Zhao ◽  
Chengwei Chen ◽  
Liang’an Zhang ◽  
Xinjian Lu
Keyword(s):  
Feedback Loop ◽  
Control Method ◽  
Virtual Work ◽  
Parallel Robot ◽  
Torque Control ◽  
Virtual Work Principle ◽  
Tuning Method ◽  
Computed Torque Control ◽  
Control Feedback ◽  
Computed Torque

SUMMARY In this paper, an online self-gain tuning method of a PD computed torque control (CTC) is used for a 3UPS-PS parallel robot. The CTC is applied to the 3UPS-PS parallel robot based on the robot dynamic model which is established via a virtual work principle. The control system of the robot comprises a nonlinear feed-forward loop and a PD control feedback loop. To implement real-time online self-gain tuning, an adjustment method based on the genetic algorithm (GA) is proposed. Compared with the traditional CTC, the simulation results indicate that the control algorithm proposed in this study can not only enhance the anti-interference ability of the system but also improve the trajectory tracking speed and the accuracy of the 3UPS-PS parallel robot.

scholarly journals Application of the virtual work principle to compute magnetic forces with a volume integral method

2013 ◽  
Vol 27 (3) ◽  
pp. 418-432 ◽  
Author(s):  
Anthony Carpentier ◽  
Nicolas Galopin ◽  
Olivier Chadebec ◽  
Gérard Meunier ◽  
Christophe Guérin
Keyword(s):  
Integral Method ◽  
Virtual Work ◽  
Volume Integral ◽  
Virtual Work Principle ◽  
Magnetic Forces

scholarly journals Newton Type Iteration for Tikhonov Regularization of Nonlinear Ill-Posed Problems in Hilbert Scales

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Monnanda Erappa Shobha ◽  
Santhosh George
Keyword(s):  
Integral Equation ◽  
Iterative Method ◽  
Iterative Scheme ◽  
Initial Guess ◽  
Optimal Order ◽  
Source Condition ◽  
Adaptive Scheme ◽  
Actual Solution ◽  
Ill Posed ◽  
General Source

Recently, Vasin and George (2013) considered an iterative scheme for approximately solving an ill-posed operator equationF(x)=y. In order to improve the error estimate available by Vasin and George (2013), in the present paper we extend the iterative method considered by Vasin and George (2013), in the setting of Hilbert scales. The error estimates obtained under a general source condition onx0-x^(x0is the initial guess andx^is the actual solution), using the adaptive scheme proposed by Pereverzev and Schock (2005), are of optimal order. The algorithm is applied to numerical solution of an integral equation in Numerical Example section.

Study on Drive Characteristic of Multi–Rope Friction Winder Using Functional Virtual Prototyping

2009 ◽  
Vol 628-629 ◽  
pp. 305-310
Author(s):  
Yi Liu ◽  
Guo Ding Chen ◽  
J.S. Li ◽  
Y.J. Xue
Keyword(s):  
Software Package ◽  
3D Model ◽  
Virtual Work ◽  
Virtual Prototyping ◽  
Research Work ◽  
Three Dimensional ◽  
Virtual Work Principle ◽  
Nodal Method ◽  
Hoisting System ◽  
Dynamics Characteristic

The main objective of this study was to model and simulate a reduced three-dimensional (3D) model for researching the hoisting system of a Multi – rope Friction Winder. By introducing the relative nodal method, the simplified dynamic equations have been derived via the virtual work principle and validated on a virtual prototype with the RecurDyn software package. Kinematics and dynamics characteristic date are obtained by computer-aided dynamic simulation of virtual Multi – rope friction winder. The result is in accord with theoretical analysis. The research work will provide a powerful tool and useful method for the design of economic and credible elevator system. The approach can be generalized to analysis other flexible drive fields.

A droplet deformation and breakup model based on virtual work principle

2015 ◽  
Vol 27 (3) ◽  
pp. 032103 ◽  
Author(s):  
Arash B. Sichani ◽  
Mohsen D. Emami
Keyword(s):  
Virtual Work ◽  
Droplet Deformation ◽  
Virtual Work Principle ◽  
Model Based ◽  
Breakup Model

scholarly journals Design of a Monolithic Double-Slider Based Compliant Gripper with Large Displacement and Anti-Buckling Ability

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 665 ◽  
Author(s):  
Hao ◽  
Zhu
Keyword(s):  
Virtual Work ◽  
Large Displacement ◽  
Amplification Coefficient ◽  
Element Analysis ◽  
Virtual Work Principle ◽  
Manipulation System ◽  
The Finite Element Analysis ◽  
Rigid Body Model ◽  
Analytical Relations ◽  
Kinematic Mechanism

In a micro-manipulation system, the compliant gripper is used for gripping, handling and assembling of objects. Large displacement and anti-buckling characteristics are desired in the design of the gripper. In this paper, a compliant gripper with these two characteristics is proposed, modelled and verified. The large displacement is enabled by using distributed compliance in a double-slider kinematic mechanism. An inverted flexure arrangement enables the anti-buckling of the gripper when closing the two jaws. A pseudo-rigid-body model (PRBM) method with the help of virtual work principle is employed to obtain several desired analytical relations including the amplification coefficient and kinetostatics. The results of the finite element analysis (FEA) are shown to be consistent with the results of the derived analytical model. An experimental test was carried out through a milling machined aluminium alloy prototype, the results of which verify the good performance of the compliant gripper.

Optimal Reduction Ratio Selection for the Driving System of a Novel High-Speed Parallel Manipulator

2007 ◽  
Author(s):  
Xianmin Zhang ◽  
Jianfeng Yuan
Keyword(s):  
Parallel Manipulator ◽  
High Speed ◽  
Inverse Dynamics ◽  
Virtual Work ◽  
Operation Time ◽  
Reduction Ratio ◽  
Virtual Work Principle ◽  
Driving System ◽  
S Curve ◽  
The Cost

The reduction ratio of the driving system plays a very important role in the accelerating and decelerating capacity for a parallel manipulator. In this paper, the virtual work principle was employed to develop the inverse dynamics model of a novel high-speed parallel manipulator. A new S-curve speed profile was introduced and adopted to plan the trajectory of the end-effecter of the manipulator in the operation space. Aiming at the minimal operation time, a reduction ratio optimal selection method of the driving system was presented, which can make full use of the advantages of the AC servomotor and consequently reduce the cost of the manipulator.

Dual Approach for Electromechanical Coupling in MEMS

2009 ◽  
Author(s):  
Ve´ronique Rochus ◽  
Jean-Claude Golinval ◽  
Christophe Geuzaine
Keyword(s):  
Electromechanical Coupling ◽  
Virtual Work ◽  
Scalar Potential ◽  
Test Cases ◽  
Electrostatic Problem ◽  
Dual Approach ◽  
Virtual Work Principle ◽  
Potential Formulation ◽  
Primal And Dual ◽  
Analytic Derivation

In this paper we present an approach for the computation of coupled electromechanical problems in micro-electromechanical systems based on a vector potential formulation of the electrostatic problem. This formulation is the dual of the scalar potential approach commonly used in the literature. We present an analytic derivation of the force computed using this dual method based on the virtual work principle, and compare the primal and dual approaches on the finite element solution of simple two-dimensional test-cases.

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