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

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.

Download Full-text

Inverse Dynamics of 2UPS-2RPS Parallel Mechanism Based on Virtual Work Principle

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.29-32.744 ◽

2010 ◽

Vol 29-32 ◽

pp. 744-749 ◽

Cited By ~ 3

Author(s):

Wen Hua Wang ◽

Zhi You Feng ◽

Ting Li Yang ◽

Ce Zhang

Keyword(s):

Computer Simulation ◽

Kinematic Analysis ◽

Parallel Mechanism ◽

Inverse Dynamics ◽

Virtual Work ◽

Dynamic Equations ◽

Inverse Dynamic ◽

Virtual Work Principle ◽

Inverse Dynamic Model ◽

Moving Platform

Inverse dynamic equations of the 2UPS-2RPS mechanism are formulated by utilizing the virtual work principle. Kinematic analysis of the mechanism is presented, on the basis of which the Jacobian matrices of the limbs and the mechanism are deduced. By combining the dynamics of the limbs and the moving-platform, the inverse dynamic model of the mechanism is obtained. Finally a computer simulation is carried out to demonstrate the dynamic analysis of the moving platform.

Download Full-text

An Efficient Calibration Method for 6 DOF Parallel Mechanism (2nd Report, Analysis of the Calibration Matrix Using Singular Value Decomposition)

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.79.3662 ◽

2013 ◽

Vol 79 (806) ◽

pp. 3662-3671

Author(s):

Nobuharu MIMURA

Keyword(s):

Singular Value Decomposition ◽

Parallel Mechanism ◽

Calibration Method ◽

Singular Value ◽

Report Analysis ◽

Calibration Matrix ◽

Value Decomposition

Download Full-text

The Mechanics of Parallel Mechanisms and Walking Machines

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/pime_proc_1994_208_142_02 ◽

1994 ◽

Vol 208 (6) ◽

pp. 367-377 ◽

Cited By ~ 2

Author(s):

S J Zhang ◽

D J Sanger ◽

D Howard

Keyword(s):

Parallel Mechanism ◽

Virtual Work ◽

The Body ◽

Position Vector ◽

Parallel Mechanisms ◽

Active Joint ◽

End Effector ◽

Walking Machine ◽

Walking Machines ◽

Fixed Base

A parallel mechanism is one whose links and joints form two or more serially connected chains which join the fixed base and the end effector The mechanism of a multi-legged walking machine can be considered as a parallel mechanism whose base is not fixed and whose configuration changes during different phases of its gait. This paper presents methods for analysing the mechanics of parallel mechanisms and walking machines using vector and screw algebra Firstly, displacement analysis is covered; this includes general methods for deriving the position vector of any joint in any leg and for calculating the active joint displacements in any leg. Secondly, velocity analysis is covered which tackles the problem of calculating active joint velocities given the velocity, position and the orientation of the body and the positions of the feet. Thirdly, the static analysis of these classes of mechanisms using the principle of virtual work and screw algebra is given. Expressions are derived for the actuator forces and torques required to balance a given end effector (or body) wrench and, in the case of a walking machine, the ground reactions at the feet. Numerical examples are given to demonstrate the application of these methods.

Download Full-text

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

Volume 10: 44th Mechanisms and Robotics Conference (MR) ◽

10.1115/detc2020-22012 ◽

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.

Download Full-text

Dynamic Formulation and Performance Comparison of the 3-DOF Modules of Two Reconfigurable PKM—the Tricept and the TriVariant

Journal of Mechanical Design ◽

10.1115/1.1992511 ◽

2005 ◽

Vol 127 (6) ◽

pp. 1129-1136 ◽

Cited By ~ 84

Author(s):

Meng Li ◽

Tian Huang ◽

Jiangping Mei ◽

Xueman Zhao ◽

Derek G. Chetwynd ◽

...

Keyword(s):

Virtual Work ◽

Dynamic Performance ◽

Performance Comparison ◽

Inverse Dynamic ◽

Virtual Work Principle ◽

Joint Force ◽

Inertial Parameters ◽

Dynamic Formulation ◽

Performance Evaluation And Comparison ◽

And Performance

Utilizing the virtual work principle, this paper presents a method for the inverse dynamic formulation of the 3-degree-of-freedom (DOF) modules of the well-known Tricept robot and a newly invented hybrid robot named TriVariant. The TriVariant is a modified version of the Tricept, achieved by integrating one of the three active limbs into the passive one. Both local and global conditioning indices are proposed for the dynamic performance evaluation and comparison of these two robots. These indices are designed on the basis of the maximum actuated joint force required for producing a unit acceleration of the mobile platform. For a given set of geometrical and inertial parameters, it has been shown that the TriVariant has a similar overall dynamic performance compared with that of the Tricept.

Download Full-text