Backlash Compensation on CNC Machine Tool Based on Semi-Closed Loop Control

2011 ◽  
Vol 346 ◽  
pp. 644-649 ◽  
Author(s):  
Bin Feng ◽  
Xue Song Mei ◽  
Liang Guo ◽  
Dong Sheng Zhang ◽  
You Long Cheng
Keyword(s):  
Machine Tool ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Positional Accuracy ◽  
Loop Control ◽  
Open Cnc ◽  
Contouring Error ◽  
Open Cnc System

The positional accuracy and machining precision are mainly affected by backlash for semi-closed loop control CNC machine tool. And compensation for backlash is essential to improving the accuracy of machine tool. A method is developed to reduce contouring error in this paper. A simulated model of backlash and Open CNC system are used to verify compensation algorithm. Computational simulations and experimental results have shown that the contouring error due to backlash can be greatly reduced by using backlash compensation.

scholarly journals Reformation and Commissioning Research on Closed-Loop Control of Y Axis CNC Milling Machine

2015 ◽  
Vol 9 (1) ◽  
pp. 613-617
Author(s):  
Tang Guolan ◽  
Wu Yunzhong
Keyword(s):  
Closed Loop ◽  
Closed Loop Control ◽  
Milling Machine ◽  
Cnc Machine Tool ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Loop Control ◽  
Cnc Milling Machine ◽  
Driven System ◽  
Setting Parameters

Considering its working stability, semi-closed loop control is usually used in middle - grade CNC machine tool. But in the control，processing quality and machining precision are seriously affected by wear, hot variant, screw error and backlash of machine driven system. In order to improve them, reformation processing on closed-loop of Y axis in THWMZT-1B CNC milling machine is introduced, such as connecting and installing hardware, setting parameters and backlash compensating. After commissioning it is satisfying that repeated positioning accuracy can reach 0.001mm.

Research on Error Compensation by Semi-Closed Loop Control for a 3-UPS Parallel Machine Tool

2012 ◽  
Vol 461 ◽  
pp. 272-276
Author(s):  
Jian Ye Guo ◽  
Jia Shun Shi ◽  
Liang Zhao
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Closed Loop ◽  
Parallel Machine ◽  
Control Mode ◽  
Closed Loop Control ◽  
Kinematics Analysis ◽  
Compensation Strategy ◽  
Loop Control ◽  
Parallel Machine Tool

This paper took a 3-UPS Parallel Machine Tool (PMT) as the object of research; it mainly introduced the process of establishing the compensation strategy for this PMT. Firstly the kinematics equations on driving chain and constraint chain was established on the basis of kinematics analysis. Then according to the structural characteristics and the results of kinematics analysis, the error compensation strategy of feedback correction type with the semi-closed loop control mode was used in the error compensation for this PMT by the method of installing respectively the encoders on the each joint of parallelogram mechanism, namely the compensation way of “parallel driving and series feedback” was adopted. Finally this paper has also deduced the theoretical model of error compensation. The research results in this paper provided a theoretical basis for realizing error compensation of this PMT, and had important practical significance for improving machining precision of PMT

scholarly journals Static and Dynamic Characterization and Control of a High-Performance Electro-Hydraulic Actuator

Actuators ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 46
Author(s):  
Govind N. Sahu ◽  
Suyash Singh ◽  
Aditya Singh ◽  
Mohit Law
Keyword(s):  
Machine Tool ◽  
High Performance ◽  
Closed Loop ◽  
Dynamic Models ◽  
Static Model ◽  
Dynamical Model ◽  
Model Parameters ◽  
Closed Loop Control ◽  
Hydraulic Actuator ◽  
Loop Control

This paper characterizes the static, dynamic, and controlled behavior of a high-performance electro-hydraulic actuator to assess its suitability for use in evaluating machine tool behavior. The actuator consists of a double-acting piston and cylinder arrangement controlled by a servo valve and a separate rear chamber controlled by a separate valve, designed to work in conjunction to generate static forces of up to 7000 N that can be superposed with dynamic forces of up to ±1500 N. This superposition of periodic forces with a non-zero mean makes the actuator capable of applying realistic loading conditions like those experienced by machines during cutting processes. To characterize the performance of this actuator, linearized static and dynamic models are described. Since experiments with the actuator exhibit nonlinear characteristics, the linearized static model is expanded to include the influence of nonlinearities due to flow, leakages, saturations, and due to friction and hysteresis. Since all major nonlinearities are accounted for in the expanded static model, the dynamical model remains linear. Unknown static and dynamical model parameters are calibrated from experiments, and the updated models are observed to capture experimentally observed behavior very well. Validated models are used to tune the proportional and integral gains for the closed-loop control strategy, and the model-based tuning in turn guides appropriate closed-loop control of the actuator to increase its bandwidth to 200 Hz. The statically and dynamically characterized actuator can aid machine tool structural testing. Moreover, the validated models can instruct the design and development of other higher-performance electro-hydraulic actuators, guide the conversion of the actuator into a damper, and also test other advanced control strategies to further improve actuator performance.

scholarly journals Global Quantitative Sensitivity Analysis and Compensation of Geometric Errors of CNC Machine Tool

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Shijie Guo ◽  
Dongsheng Zhang ◽  
Yang Xi
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tool ◽  
Machine Tools ◽  
Geometric Error ◽  
Test Method ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Cnc Machine ◽  
Open Cnc ◽  
Open Cnc System

A quantitative analysis to identify the key geometric error elements and their coupling is the prerequisite and foundation for improving the precision of machine tools. The purpose of this paper is to identify key geometric error elements and compensate for geometric errors accordingly. The geometric error model of three-axis machine tool is built on the basis of multibody system theory; and the quantitative global sensitivity analysis (GSA) model of geometric error elements is constructed by using extended Fourier amplitude sensitivity test method. The crucial geometric errors are identified; and stochastic characteristics of geometric errors are taken into consideration in the formulation of building up the compensation strategy. The validity of geometric error compensation based on sensitivity analysis is verified on a high-precision three-axis machine tool with open CNC system. The experimental results show that the average compensation rates along theX,Y, andZdirections are 59.8%, 65.5%, and 73.5%, respectively. The methods of sensitivity analysis and geometric errors compensation presented in this paper are suitable for identifying the key geometric errors and improving the precision of CNC machine tools effectively.

A new contouring error estimation for the high form accuracy of a multi-axis CNC machine tool

2018 ◽  
Vol 101 (5-8) ◽  
pp. 1403-1421 ◽  
Author(s):  
Jing Zhang ◽  
Jiexiong Ding ◽  
Qingzhao Li ◽  
Zhong Jiang ◽  
Qicheng Ding ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Estimation ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Form Accuracy ◽  
Contouring Error ◽  
High Form

Technology of Online Inspection in CNC Machine Tool

2016 ◽  
Vol 693 ◽  
pp. 1492-1497
Author(s):  
Zhi Qiang Yu ◽  
Tai Yong Wang ◽  
Yong Wang ◽  
Hong Bin Li ◽  
Yu Long Wang ◽  
...  
Keyword(s):  
Control Program ◽  
Inspection System ◽  
Cnc Machine Tool ◽  
Simulation Function ◽  
Cnc Machine ◽  
Open Cnc ◽  
Programming Tool ◽  
C Programming ◽  
Open Cnc System ◽  
Online Inspection

In this paper, an online inspection system is developed based on TDNC-H8 open CNC system. The system includes motion control, program management, the preservation and processing of the result and other functions. To check the rationality of inspection route, optimize and modify the inspection program, avoid accidental collision, online inspection simulation function is developed with Visual C++ programming tool and OpenGL graphics library.

Modelling, Identification and Control of Thermal Deformation of Machine Tool Structures, Part 4: A Multi-Variable Closed-Loop Control System

1999 ◽  
Vol 121 (3) ◽  
pp. 509-516 ◽  
Author(s):  
S. Fraser ◽  
M. H. Attia ◽  
M. O. M. Osman
Keyword(s):  
Control System ◽  
Machine Tool ◽  
Thermal Deformation ◽  
Closed Loop ◽  
Transfer Functions ◽  
Closed Loop Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Machine Tool Structures

A multi-variable closed-loop control system is proposed to compensate for the thermal deformation of machine tool structures. The control system recognizes the fact the relative thermal displacement between the tool and workpiece is not accessible for direct measurement. Using the generalized thermoelastic transfer functions of the structure, which provide satisfactory input-output dynamic dependencies, the heat input to the structure and thermal displacements are estimated in real time. Artificial heating elements are used as the actuation mechanism of the control system, since they provide an economical solution for retrofitting existing conventional machine tools, and can also be combined with NC controllers to effect the desired compensation of the expansion and bending modes of deformation. Computer simulation test results indicated that even when the random temperature measurement and power actuation errors are taken in consideration, an accuracy of better than 2.5 μm and a control cycle of the order of 1 second are achievable.

The Error Compensation Strategy of 3-TPT Parallel Machine Tool Based on Semi-Closed Loop Control

2011 ◽  
Vol 321 ◽  
pp. 176-179
Author(s):  
Jian Ye Guo ◽  
Zhong Qi Sheng ◽  
Liang Zhao
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Closed Loop ◽  
Parallel Machine ◽  
Control Mode ◽  
Closed Loop Control ◽  
Kinematics Analysis ◽  
Compensation Strategy ◽  
Loop Control ◽  
Parallel Machine Tool

This paper took a kind of 3-TPT Parallel Machine Tool (PMT) as the object of research; it mainly introduced the process of establishing the compensation strategy for this PMT. Firstly the kinematics equation of this PMT was established on the basis of kinematics analysis, the results showed that the kinematics equation of this PMT have characteristics that are simple calculation, explicit expression and unique solution. Then according to the structural characteristics and the results of kinematics analysis, the error compensation strategy of feedback correction type with the semi-closed loop control mode was used in the error compensation for this PMT by the method of assembling the gratings on the driving rods, namely the compensation way of “parallel driving and parallel feedback” was adopted. The research results in this paper provided a theoretical basis for realizing error compensation of this PMT, and had important practical significance for improving machining precision of PMT.

The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations

2012 ◽  
Vol 220 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Sandra Sülzenbrück
Keyword(s):  
Empirical Research ◽  
Visual Feedback ◽  
Closed Loop ◽  
Motor Planning ◽  
Visual Input ◽  
Closed Loop Control ◽  
Loop Control ◽  
Feedback Type ◽  
Effective Use ◽  
The Impact

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.

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