Analysis on the Impact of the Error Mapping for Structural Parameters of Parallel Machine Tool

2011 ◽  
Vol 188 ◽  
pp. 515-520 ◽  
Author(s):  
Yong Geng Wei ◽  
Zhong Xian Wang
Keyword(s):  
Performance Evaluation ◽  
Machine Tool ◽  
Attitude Change ◽  
Structural Parameters ◽  
Parallel Machine ◽  
Evaluation Index ◽  
Performance Evaluation Index ◽  
Moving Platform ◽  
Parallel Machine Tool ◽  
The Impact

In order to improve the 6-DOF parallel machine tool motion accuracy and reduce error, the impact of the error mapping for Structural Parameters of Parallel Machine Tool is analyzed. The fixing platform and the moving platform of 6-DOF PMT are linked by six variable-length rod with the kinematic pair (hooke hinge or hooke hinge). By changing the length of the drive rod, causing moving platform position and attitude change, a variety of motion can be simulated and emulated. If the cut tool is installed on the moving platform, the various surface parts can be machined, shown in Figure 1. The above figure shown, in order to obtain the moving platform trajectory, we need measure hooke hinge space position of the fixing platform and the moving platform[1]. There are 6 hooke hinges on the fixing platform and there are 3 parameters (x, y, z) on every hooke hinge. There are 6 hooke hinges on the moving platform and there are 3 parameters (x, y, z) on every hooke hinge. So a total of 12 hooke hinges positions (36 parameters) need be measured. Due to the actual processing, assembly and measurement error, the actual measured values and theoretical values for 36 parameters can not be a complete match and lead to the moving platform errors. This paper will study the 36 parameters on the impact of mapping errors. Firstly, the error mapping formula between drive rod and the moving platform for PMT is established, secondly the performance evaluation index of the error mapping is deducted, and then the relationship between 36 parameters and the error mapping index is established. At last, to the different types of PMT structures and structural parameters, the ideal structural parameters with the aid of the performance evaluation index are optimized.

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.

The Research on the Workspace of the 3-TPT Parallel Machine Tool

2013 ◽  
Vol 385-386 ◽  
pp. 69-72 ◽  
Author(s):  
Heng Hua Zhao ◽  
Hui Yang ◽  
Hong Shuan Fu
Keyword(s):  
Machine Tool ◽  
Motion Planning ◽  
Mechanical Design ◽  
Parallel Machine ◽  
Important Data ◽  
Important Indicator ◽  
Tool Performance ◽  
Moving Platform ◽  
Simulation Results ◽  
Parallel Machine Tool

The workspace of a machine tool is an important indicator to measure a machine tool performance as well as the important data of mechanical design and motion planning. This article in view of the 3-TPT parallel machine tool. First, according to the positive and inverse solution of Mechanism kinematics, the expression of the range of motion of the moving platform reference point was calculated. Then, by considering the effects of rod length and Hooke joints on the workspace, the workspace could be simulated by using MATLAB software and LabVIEW software.The simulation results show that the parallel machine tool workspace is continuous and no caves.

A Study on Dynamics of 2-PRR Parallel Machine Tool Based on the Lagrange Equation

2011 ◽  
Vol 295-297 ◽  
pp. 1373-1379
Author(s):  
Suo Xian Yuan ◽  
Dan Dan Shen
Keyword(s):  
Machine Tool ◽  
Dynamic Equation ◽  
Lagrange Equation ◽  
Parallel Machine ◽  
Displacement Velocity ◽  
Dynamics Analysis ◽  
Moving Platform ◽  
Parallel Machine Tool

Based on the Lagrange equation, a dynamic equation of 2-PRR parallel machine tool has been established and the relation among displacement,velocity and acceleration of moving platform was given. By modeling and simulating on the simulink of Matlab, forword dynamics are solved. This paper also provide a reference for dynamics analysis and optimization of less freedom machine tool

Statics Analysis and Design of the 6-DOF Lower Limb Bionic Leg

2016 ◽  
Vol 26 ◽  
pp. 1-12 ◽  
Author(s):  
Li Wen Chen ◽  
Bing Yan Cui ◽  
Zhi Jun Wang ◽  
Ling Chao Meng ◽  
Zhan Xian Li
Keyword(s):  
Performance Evaluation ◽  
Carrying Capacity ◽  
Lower Limb ◽  
Evaluation Index ◽  
Structure Parameters ◽  
Transmission Performance ◽  
Analysis And Design ◽  
Static Performance ◽  
Performance Evaluation Index ◽  
Moving Platform

In order to improve ability of walking and crossing the barriers , increase the carrying capacity, and enhance its popularity and adaptability, a novel lower limb bionic leg is presented based on 3-UPS parallel mechanism, which has the characteristics of movement flexible and strong adaptability. It is very important analysis to statics of lower limb bionic leg. Firstly, statics equation of the lower limb bionic leg of driving force and output force is established based on virtual work principle. Secondly, static performance evaluation index is defined and the evaluation index distribution map is drawn. The relationship between the structure parameters and the static performance evaluation indexes is analyzed, obtained the influence of structure parameters on the static performance evaluation index, and a set of reasonable structural parameters is selected. The circum-radius of moving platform is 50mm, the circum-radius of the static platform is 150mm, the moving platform angle and static platform angle are equal to 60°, the lower limb bionic leg has the best load carrying capacity. Thirdly, the lower limb bionic leg is designed based on statics analysis and structure parameters optimization. Analysis results show that the lower limb bionic leg has good static transmission performance at the initial position, and the static transmission performance decreases with increasing turning workspace. The static transmission performance decreases with z axle displacement increasing. The analysis results laid a foundation for further analysis and research of the lower limb bionic leg.

Analysis of Static and Optimization of Structural Parameters for a Novel Leg Mechanism

2013 ◽  
Vol 646 ◽  
pp. 144-149 ◽  
Author(s):  
Bing Yan Cui ◽  
Zhen Lin Jin
Keyword(s):  
Performance Evaluation ◽  
Structural Parameters ◽  
Evaluation Index ◽  
Space Model ◽  
Work Spaces ◽  
Calculation Process ◽  
Structural Dimensions ◽  
Performance Atlas ◽  
Static Performance ◽  
Performance Evaluation Index

In order to increase wosrkspace and carrying capacity of leg mechanism and improve popularity and adaptability of leg mechanism, a novel mechanism is proposed which has three branches of 6-DOF, which used 3-UPS parallel mechanism as the prototype of the mechanism. The static performance of the leg mechanism is analyzed and the structure parameters are designed. First, the static transmission equation of the leg mechanism is established by using the principle of virtual works which simplifies the calculation process of the leg mechanism. Further, the static performance evaluation index and the global torque performance evaluation index are defined, and the performance atlas of the static performance evaluation index is plotted at the work spaces of the leg mechanism. Moreover, by using of the space model theory, the structural dimensions parameters are optimized of the leg mechanism. Finally, using a set of optimal structural dimensions parameters and the virtual prototype of leg mechanism is designed. The research provides a theoretical basis for further investigation on leg mechanism.

Accuracy Analysis and Simulation of Three Degrees of Freedom Parallel Machine Tool

2010 ◽  
Vol 37-38 ◽  
pp. 73-76
Author(s):  
Xing Shan Li ◽  
Jun Wang ◽  
Guang Qi Cai
Keyword(s):  
Machine Tool ◽  
Degrees Of Freedom ◽  
Influence Factors ◽  
Parallel Machine ◽  
Matrix Methods ◽  
Fixed Base ◽  
Moving Platform ◽  
Parallel Machine Tool ◽  
Serial Chains ◽  
Three Degrees Of Freedom

This paper proposes a novel three degrees of freedom parallel machine tool. The parallel machine tool consists of three serial chains and a fixed base and a moving platform which can be moved in a pose space corresponding to the three degrees of freedom. By using matrix methods, a error model of the parallel machine was developed. The explicit solution of the error of joint and the stroke error of telescopic link were solved for analysis of influence factors of error on the position of moving platform. It provided a theoretical foundation for error compensation of parallel machine tool.

Kinematic Performance of 5-UPS/PRPU 5-Axis Parallel Machine Tool

2004 ◽  
Author(s):  
Yong Sheng Zhao ◽  
Kui Jing Zheng ◽  
Qin Chuan Li ◽  
Xiao Jing Tian ◽  
Yan Ming Qin
Keyword(s):  
Machine Tool ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Vertical Axis ◽  
Parallel Machine ◽  
Parameter Method ◽  
Solution Equation ◽  
Axis Parallel ◽  
Moving Platform ◽  
Parallel Machine Tool

A novel 5-UPS/PRPU 5-axis PMT (Parallel Machine Tool) is studied. The stationary platform is connected with the moving platform by the same five UPS actuated limbs and a PRPU passive constraining limb. Three translational DOF (degrees of freedom) and two rotational DOF can be achieved. by using kinematic screw theory and D-H parameter method, the kinematic forward and inverse solutions of the PRPU constraining limb are deduced. The rotational constraint along the vertical axis of the moving platform acted by the PRPU limb is confirmed. Moreover, the configuration of the moving platform can be acquired online by installing sensors on the joints of the constraining limb. The kinematic inverse solution equation and jacobian matrix for this 5-axis PMT are presented. Finally the workspace and the dexterity of the PMT are analyzed. Theoretical analysis is proved by the actual operation of the prototype of the 5-UPS/PRPU 5-axis PMT in our laboratory.

scholarly journals Contribution Modeling on Condition Evaluation of Asphalt Pavement Using Uncertainty Measurement and Entropy Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-10 ◽  
Author(s):  
Jue Li ◽  
Hui Wei ◽  
Yongsheng Yao ◽  
Xin Hu ◽  
Lei Wang
Keyword(s):  
Performance Evaluation ◽  
Evaluation Index ◽  
Pavement Performance ◽  
Entropy Theory ◽  
Minimum Entropy ◽  
Uncertainty Measurement ◽  
Measurement Function ◽  
Performance Evaluation Index ◽  
Index Weight ◽  
The Impact

In view of the deficiency that traditional pavement performance evaluation index did not consider the influence of their difference on weight, the grade of the evaluation index also did not take into account intermediate state and the impact of uncertainty on the evaluation results, a determination method of pavement performance evaluation index weight based on entropy theory was developed. The unascertained measurement function of evaluation index was performed by left-half ladder distribution, and unascertained measurement matrix was obtained. The index weight was calculated by minimum entropy theory, and the practicability of this method was verified through a concrete example finally. The results show that there were different weights in different samples, which depended on index measurement function and were the overall characterization of comprehensive measurement of every index. The method which is based on the given weighting factor did not conform to the engineering facts. It was difficult to identify the importance of the pavement performance evaluation index in different samples. The balance of the various indexes is better to be considered in the proposed method, and the comprehensive situation of pavement performance is really reflected, which improves the evaluation of the reliability.

Study on Parameter Optimization Based on Workspace of 3-DOF Parallel Machine Tool

2010 ◽  
Vol 29-32 ◽  
pp. 2247-2250
Author(s):  
Xing Shan Li ◽  
Guang Qi Cai
Keyword(s):  
Machine Tool ◽  
Parameter Optimization ◽  
Optimization Model ◽  
Explicit Solution ◽  
Structural Parameters ◽  
Optimization Method ◽  
Parallel Machine ◽  
Parameters Optimization ◽  
Workspace Analysis ◽  
Parallel Machine Tool

This paper proposes an optimization method which makes the structural parameters are minimum and the workspace is maximum based on 3-DOF parallel machine tool. By analysis the conditions of boundary, parameters optimization model is built and gives out the explicit solution of dexterous workspace. Analysis the effect of structural parameters on workspace. The results show the workspace is a unsingularity space.

Design of a novel 5-DOF parallel kinematic machine tool based on workspace

Robotica ◽  
2005 ◽  
Vol 23 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Feng Gao ◽  
Binbin Peng ◽  
Weimin Li ◽  
Hui Zhao
Keyword(s):  
Machine Tool ◽  
Graphical Representation ◽  
Parallel Machine ◽  
Parallel Kinematic Machine ◽  
Reachable Workspace ◽  
Dimensional Parameters ◽  
Parallel Kinematic ◽  
Moving Platform ◽  
Parallel Machine Tool ◽  
Orientation Workspace

In this paper an inverse concept idea is presented to determine the main configuration dimensional parameters of a novel 5-DOF parallel kinematic machine tool. By the new described orientation workspace, the motion of the passive joints on the moving platform can be expressed in the fixed coordinate analytically. Some relationships between the reachable workspace and the dimensional parameters of the parallel machine tool have been obtained with graphical representation.

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