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.

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.

A 3-DOF Parallel Manipulator Based 5-Axis Parallel Kinematics Machine Tool

2011 ◽  
Vol 317-319 ◽  
pp. 698-702
Author(s):  
Wen Jia Chen ◽  
Lan Lei Zhao ◽  
Jiang Zhang
Keyword(s):  
Machine Tool ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Parallel Machine ◽  
Virtual Manufacturing ◽  
Control Mode ◽  
Work Piece ◽  
Nc System ◽  
Axis Parallel ◽  
Parallel Machine Tool

Though computer technology has brought about virtual manufacturing to expedite design and analysis through simulation and visualization, machines remain essential, as ultimately products need to be made. This paper presents a new type of 5-axis parallel machine tool based on a 3 degrees of freedom parallel platform manipulator with base mounted prismatic actuators. This machine tool is different from the Stewart platform type parallel machine tool in that its feed motion in X-direction is realized by the worktable on which work-piece is fixed and the parallel manipulator sliding on the gantry structure of the machine tool is responsible for the translation along Y-direction instead of the movable platform of the manipulator. Due to this special architecture, the workspace in X-direction and Y-direction of the new machine tool is enlarged greatly. And its rigidity is higher because of the adaptation of gantry structure. This machine tool is controlled by a PC based NC system in simultaneous 5 axes control mode.

Actuating Input Selection of 5-UPS/PRPU Parallel Machine Tool

2005 ◽  
Author(s):  
Jian-She Gao ◽  
Ren-Cheng Zheng ◽  
Yong-Sheng Zhao
Keyword(s):  
Parallel Mechanism ◽  
Basic Problem ◽  
Screw Theory ◽  
Parallel Machine ◽  
Condition Numbers ◽  
Constraint Matrix ◽  
Input Selection ◽  
Moving Platform ◽  
Parallel Machine Tool ◽  
Selection Of

The actuating input selection is an important basic problem for the parallel mechanism. Based on the screw theory, the constraint screw can be got after locking a kinematic pair in any limb, which can be taken as actuating wrench acted on the moving platform of the parallel mechanism. The constraint screw matrix is composed of the structure constraint screws and the constraint screws of the actuating pairs. The reasonableness of input selection can be judged by the rank of the constraint matrix. The performance of the combinations of actuating inputs is evaluated by the condition numbers of the force constraint matrix and the torque constraint matrix respectively. The theory presented is validated by the simulation and the maching test.

Development of NC System of the 3-PUU Parallel Machine Tool Based on PMAC

2010 ◽  
Vol 142 ◽  
pp. 233-237
Author(s):  
Hai Peng Lin ◽  
Yi Min Xu
Keyword(s):  
Machine Tool ◽  
Real Time ◽  
Degrees Of Freedom ◽  
Rocket Engine ◽  
Parallel Machine ◽  
Numerical Control ◽  
Interface Position ◽  
Loop Control ◽  
Nc System ◽  
Parallel Machine Tool

In this paper, a PUU parallel machine tool with three translational degrees of freedom (DOF) is designed which is usually used in the complex grain machining of the solid rocket engine.， and its numerical control system is described in detail. The so-called “PC+PMAC” is used as the hardware platform, and Windows as the software one, the parallel machine tool NC system is built. The features, such as multi-axis motion control and fast real time communication of PMAC, software resources and efficient data processing of PC are utilized such that Man Machine Interface, position servo control, real time measurement of cutter configuration and closed loop control of the parallel machine tool are realized.

A Novel 5-DOF NC Serial-Parallel Machine Tool and its Position Analysis

2010 ◽  
Vol 431-432 ◽  
pp. 355-360
Author(s):  
Hong Jun San ◽  
Shi Sheng Zhong ◽  
Zhi Xing Wang
Keyword(s):  
Machine Tool ◽  
Analytical Method ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Structural Characteristics ◽  
Parallel Machine ◽  
Numerical Control ◽  
Forward Solution ◽  
In Series ◽  
Parallel Machine Tool

In this paper, a novel 5 degrees-of-freedom (DOF) numerical control (NC) serial-parallel machine tool is proposed. It can provide 3 translational DOF and 2 rotational DOF. The proposed mechine tool is composed of a 2-TPR/2-TPS special 4-DOF parallel mechanism in series with a rotatable component. The structure of this machine tool is simple. The machine tool can process the workpieces which have complex surfaces.The structural characteristics of this machine tool is introduced. The position inverse solution of this machine tool is deduced by analytical method and the position forward solution of this machine tool is achieved by numerical method.

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.

Stiffness modelling and comparison of the 5-UPS/PRPU parallel machine tool with its non-redundant counterpart

2016 ◽  
Vol 231 (9) ◽  
pp. 1646-1657 ◽  
Author(s):  
Xin Zhou ◽  
Yundou Xu ◽  
Jiantao Yao ◽  
Kuijing Zheng ◽  
Yongsheng Zhao
Keyword(s):  
Machine Tool ◽  
Stiffness Matrix ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Virtual Work ◽  
Matrix Decomposition ◽  
Parallel Machine ◽  
Stiffness Model ◽  
Redundantly Actuated ◽  
Parallel Machine Tool

This article presents a derivation of the stiffness matrix of a general redundantly actuated parallel mechanism based on the overall Jacobian. The Jacobian of the constraints and actuations is derived using reciprocal screw theory. Based on the mapping relationship between constraint, actuated and external forces combined with the principle of virtual work, a compatibility equation for the deformation of all of the limbs is achieved, and the stiffness model of the general redundantly actuated parallel mechanism is derived. The 5-UPS/PRPU redundantly actuated parallel machine tool is used to illustrate this method. The parallel machine tool comprehensively reveals the effect of the elastic deformation of active–passive joints and some basic transmission parts. The stiffness model is further validated by experimental data. Moreover, the global stiffness matrix of the general redundantly actuated parallel mechanism can be separated into two parts via matrix decomposition. The first part is the stiffness matrix of the corresponding non-redundant parallel mechanism, and the second part is the stiffness matrix of the redundantly actuated limbs (actuators). The redundantly actuated 5-UPS/PRPU parallel machine tool is also investigated for further analysis. The different stiffness characteristics of the machine tool and its corresponding non-redundant 5-UPS/PRPU parallel machine tool are compared. Actuation redundancy is found to improve the stiffness performance of the machine tool efficiently.

Study on Machine Accuracy of the Serial-Parallel Machine Tool Based on the BP Neural Network

2009 ◽  
Vol 407-408 ◽  
pp. 140-145
Author(s):  
Xu Ming Pei ◽  
Jie Liu ◽  
Chao Zhang
Keyword(s):  
Neural Network ◽  
Machine Tool ◽  
Bp Neural Network ◽  
Error Compensation ◽  
Degrees Of Freedom ◽  
Simulation Analysis ◽  
Control Strategies ◽  
Parallel Machine ◽  
Machine Accuracy ◽  
Parallel Machine Tool

It were researched that the modeling methods of machine accuracy and the control techniques of the error compensation based on BP neural network(BPNN) for parallel machine tool(PMT)with five degrees of freedom(DOF). The samples are obtained to train the BP neural network which has good capacity for non- liner mapping, learning and generalization. The machine accuracy mathematics model is established for the error compensation, in order to study the nonlinear input and output problem of the parallel machine which difficultly modeling described. The trained neural network was applied to error compensation of PMT to realize modifying errors real-timely. Finally, simulation analysis was performed through the MATLAB software. The results expressed that the control strategies for error compensation were simple, efficient and practicable. Machine accuracy can be increased greatly after compensation.

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.

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