The Pre-Travel Error Study of Electrical Trigger Probe in On-Machine Measurement

2016 ◽  
Vol 693 ◽  
pp. 1466-1473 ◽  
Author(s):  
Yong Lin Cai ◽  
Ning Ning Cui ◽  
Xiang Mo ◽  
Xiang Kai Yao ◽  
Wei Qing Sun

On-machine measurement is a high-efficient measure method in NC machining, and there are pre-travel errors during measurement. What is more, these errors tend to present anisotropy, and affect the measurement accuracy. This paper aimed at measuring the anisotropy of probe’s pre-travel error. First, the standard ball is measured by changing the probe angle with the same machine tool moving direction, and the pre-travel errors with different probe angles under the same machine tool errors are obtained. Then, the machine tool backlash errors are measured and compensated, and the pre-travel errors with different probe angle are obtained. Finally, the mathematical model of pre-travel error is established. The method proposed in this paper can be used to determine probe’s pre-travel error with anisotropy.

2014 ◽  
Vol 556-562 ◽  
pp. 1354-1357
Author(s):  
Li Gong Cui ◽  
Gui Qiang Liang ◽  
Fang Shao

This paper presents a mathematical method to analyze the influence of each machine tool part deformation on the machining accuracy. Taking a 3-axis machine tool as an example, this paper divides the machine tool into the cutting tool sub-system and workpiece sub-system. Taking the deformation of lower surface of the machine bed as the research target, the mathematical model of the deformation on the displacement of the cutting point was established. In order to distribute the stiffness of each part, the contribution degree of each part on the machining accuracy was analyzed. Using this mathematical model, the stiffness of each part can be distributed at the design stage of the machine tool, and the machining accuracy of the machine tool can be improved economically.


Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2694 ◽  
Author(s):  
Wen Wang ◽  
Wenjun Qiu ◽  
He Yang ◽  
Haimei Wu ◽  
Guang Shi ◽  
...  

Due to the flexible and compact structures, spherical joints are widely used in parallel manipulators and industrial robots. Real-time detection of the clearance between the ball and the socket in spherical joints is beneficial to compensate motion errors of mechanical systems and improve their transmission accuracy. This work proposes an improved capacitive sensor for detecting the micro-clearance of spherical joints. First, the structure of the capacitive sensor is proposed. Then, the mathematical model for the differential capacitance of the sensor and the eccentric micro-displacement of the ball is deduced. Finally, the capacitance values of the capacitive sensor are simulated with Ansoft Maxwell. The simulated values of the differential capacitances at different eccentric displacements agree well with the theoretical ones, indicating the feasibility of the proposed detection method. In addition, the simulated results show that the proposed capacitive sensor could effectively reduce the capacitive fringe effect, improving the measurement accuracy.


Author(s):  
Yuqing Zhou ◽  
Xuesong Mei ◽  
Gedong Jiang ◽  
Nuogang Sun ◽  
Bai Shao

Simultaneous rotary-translational (R-T) axis motion error has significant influence on multi-axis machine tool precision. To improve multi-axis machine tool precision, axis motion error measurement and trace method are investigated in this study. A sensorless R-T axis motion error measurement and trace technology based on virtual bar is proposed. Firstly, the fundamental sensorless test principle is discussed. Then, the virtual-bar-based test path of a circular test though a rotary axis and two translational axes motion is scheduled. The mathematical model of motion error is established. Furthermore, to identify the error source, spatial error charts and some advanced signal processing and feature extraction technologies, such as wavelet transform and frequency analysis, are used. The analysis of experimental results shows that it is practical and efficient to use the virtual bar and the sensorless information to estimate motion error.


2014 ◽  
Vol 644-650 ◽  
pp. 215-219 ◽  
Author(s):  
Lin Cai

In this paper, the kinematics of 5-UPS parallel machine tool is analyzed, and a kinematic analysis method combining kinematic analysis and computer kinematics software is proposed. Under the premise that the parallel machine tool sector parameters is known, firstly we use the vector method to establish a mathematical model of inverse kinematics, and in accordance with a U-shaped processing trajectory the inverse solution is calculated; Secondly, three-dimensional model of the parallel machine tool is modeled in Adams, and kinematic constraints are set correctly; Finally, the inverse kinematics solution of the mathematical model is used as the Adams drive input, then the positive solutions is carried out. Compared through the Adams simulation results with U-machining path, it is verified that the inverse solution of the mathematical model and parallel machine tool bodies both are correct, it has certain significance for Parallel machine tools and other parallel robot kinematics analysis.


2011 ◽  
Vol 52-54 ◽  
pp. 156-161 ◽  
Author(s):  
Lei Zhao ◽  
Shu Gui Liu

A new type of coordinate measuring arm with a Revo revolving body which can realize quick measuring in spherical domain has high stability, fast measuring speed and high accuracy compared with common coordinate measuring arm. We use the method of space coordinate transformation to solve the problem that the transformation matrix can’t be got from Revo body to test head by DH method, and apply DH theory to build the mathematical model of system. The system model is verified right by sketching. The error model is built and the effect of measurement accuracy from all error sources is deeply analyzed. It presents a theory foundation for further researching on improving accuracy of this new type of coordinate measuring arm.


2016 ◽  
Vol 10 (3) ◽  
pp. 447-454 ◽  
Author(s):  
Yusaku Shirahama ◽  
◽  
Ryuta Sato ◽  
Yusuke Takasuka ◽  
Hidenori Nakatsuji ◽  
...  

The purpose of this study is to develop a new machine bed support mechanism for reducing the vibration generated during the high-speed tracking motion of numerical control machine tools. In order to achieve this, the frequency response and motion trajectory of a machine tool with the proposed machine bed, which has a sliding surface, are measured and compared with that of the conventional support. Based on the modal analysis of the machine tool structure, a mathematical model representing the influence of the machine bed characteristics on the vibration is also developed. The model consists of a bed, saddle, table, column, and spindle head. Every component has three degrees of freedom for each of the translational and rotational axes. In order to evaluate the characteristics of the machine bed, the mathematical model determines the stiffness and damping along the X-, Y-, and Z-axis between the bed and the ground. The frequency response curves simulated by using the mathematical model are compared with that of the measured ones. From the results of the experiments and simulations, it is confirmed that the vibration generated during high-speed tracking motions can be reduced by using the proposed machine bed with a sliding surface.


2016 ◽  
Vol 693 ◽  
pp. 1611-1617
Author(s):  
Bai Sheng Ye ◽  
Li Qiang Zhang

Aiming at the corner connection speed of continuous small blocks caused by their angle influences, the speed of transition is low and easy to cause vibration of machine tool. Research on the mathematical model of constant-speed linking of multiple periods is established by using the arc to smooth continuous small blocks, combined with the transition’s geometrical constraint, motion constraint, parameter calculation, the theory is to realize the method of high-speed interpolation of constant-speed linking of multiple periods. The result reveals that the effectiveness and practicability of the proposed method.


2014 ◽  
Vol 627 ◽  
pp. 177-181
Author(s):  
Ru Nan Liang

Force sensor based on the six degree of freedom (6-DoF) Stewart platform is universal for wide applications. Mechanism errors are significant for its measuring accuracy. However, because of the multi-variables and the complicated forms, it is difficult to solve the expression directly. The Monte Carlo method is proposed based on the analysis of the system structure and the mathematical model. The effect of mechanism errors on the measurement accuracy was assessed. With this method, a complex accuracy expression of the sensor could be avoided. It also provided a theoretical basis for designing the sensor of the Stewart platform.


2012 ◽  
Vol 252 ◽  
pp. 149-153
Author(s):  
Ling Qin Meng ◽  
Zhi Wei Wang

The screener is widely use in metallurgy, mine, etc. Now the low productivity ratio and low efficiency influence a lot to the working of factories. In this paper, we analyze the motion of object on the screener, and then build the mathematical model to maximize the productivity ratio. Take the example of straight Line vibration screeners with mode ZKB. After maximizing with our method, the result shows that our method increases 21% in the productivity ratio, and the chance of object touching the screen holes increases 45%. This paper provides an effective method for the optimal design of screener in future.The results of this study can also be applied directly to enterprise product design.


2010 ◽  
Vol 156-157 ◽  
pp. 1223-1226
Author(s):  
Pu Gao ◽  
Xiao Heng Wang

The mathematical model of the twist drill flute is discussed in the paper. The cutting tool path to machine the twist drill flute is obtained under the certain parameters in UG. And the NC machining of the twist drill flute is simulated too. After post-processing, the NC code is obtained and it is verified by virtual manufacture.


Sign in / Sign up

Export Citation Format

Share Document