Friction compensation using a double pulse method for a high-speed high-precision table

2011 ◽  
Vol 225 (5) ◽  
pp. 1263-1272 ◽  
Author(s):  
G S Chen ◽  
X S Mei ◽  
T Tao
Keyword(s):  
High Precision ◽  
High Speed ◽  
Dead Zone ◽  
Pulse Method ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Response Analysis ◽  
Cnc Machine ◽  
Time Duration ◽  
Loop Control

Friction error in reverse motion is one of the principal factors influencing the contour accuracy of high-speed and high-precision computer numerical control (CNC) machine tools, on which closed-loop control is used. On the basis of transient response analysis of servo systems which a conventional proportion–integration–differentiation control strategy are used, the reason for quadrant protrusions occurring in circular motion for worktables is discovered, and the characteristics of the friction error during the feed process such as emergence time, duration, and magnitude of the error due to friction can be predicted correctly. A new approach of compensating for friction error using double compensation pulses is proposed in this article. The first compensation pulse made the worktable escape from the dead zone at the best times, and the second one made the worktable approach to the ideal feed path along the guide as fast as possible. Parameters of compensation pulses such as magnitudes, widths, and starting time are determined by simple mathematic calculation. Results of simulations and experiments show that the method using double pulses proposed in this article can effectively compensate for the friction error in circular motions for a high-speed and high-precision table.

FPGA-Based Intelligent Software Hardening Chip for Computer Numerical Control System

2011 ◽  
Vol 105-107 ◽  
pp. 2217-2220
Author(s):  
Mu Lan Wang ◽  
Jian Min Zuo ◽  
Kun Liu ◽  
Xing Hua Zhu
Keyword(s):  
High Speed ◽  
High Performance ◽  
Large Scale ◽  
Position Control ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Cnc System ◽  
Intelligent Software

In order to meet the development demands for high-speed and high-precision of Computer Numerical Control (CNC) machine tools, the equipped CNC systems begin to employ the technical route of software hardening. Making full use of the advanced performance of Large Scale Integrated Circuits (LSIC), this paper puts forward using Field Programmable Gates Array (FPGA) for the functional modules of CNC system, which is called Intelligent Software Hardening Chip (ISHC). The CNC system architecture with high performance is constructed based on the open system thought and ISHCs. The corresponding programs can be designed with Very high speed integrate circuit Hardware Description Language (VHDL) and downloaded into the FPGA. These hardening modules, including the arithmetic module, contour interpolation module, position control module and so on, demonstrate that the proposed schemes are reasonable and feasibility.

Research and Development of a Test Platform for Synthetic Performance Parameters of Linear Motors

2011 ◽  
Vol 383-390 ◽  
pp. 4486-4491
Author(s):  
Zhong Quan Luan ◽  
Hu Yan Ji ◽  
Qing Dong Yang
Keyword(s):  
Research And Development ◽  
High Precision ◽  
Virtual Instrument ◽  
High Speed ◽  
Linear Motor ◽  
Cnc Machine Tools ◽  
Performance Parameters ◽  
Cnc Machine ◽  
Linear Motors ◽  
Test Platform

Linear Motors have been used more and more widely in high precision and high-speed linear motion for CNC machine tools, but uniform testing standards and methods for linear motor performance have not been established in China. Based on the virtual instrument software platform by means of computer technology, research and development of the test platform for synthetic performance parameters of linear motors can realize the rapid and accurate measurement, automatic storage and processing of linear-motor output, currents, positions, temperatures and other performance parameters. , Meanwhile, the platform can also provide the technical direction for design or improvement of linear motors, and technically support the formulation of related standards. Experiments showed that the test platform for synthetic performance parameters of linear motors can achieve high precision and automatic measurement to meet the testing requirements for synthetic performance of linear motors.

Recent Patents on the Structure of High-Speed Motorized Spindle

2019 ◽  
Vol 12 (2) ◽  
pp. 125-137
Author(s):  
Ye Dai ◽  
Wen-Qiang Wei ◽  
Xue-Liang Zhang ◽  
Yun-Shan Qi
Keyword(s):  
Research And Development ◽  
Machine Tool ◽  
High Precision ◽  
High Speed ◽  
Numerical Control ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Motorized Spindle ◽  
The Core ◽  
Spindle Structure

Background: As one of the core components of high-speed CNC machine tool, high-speed motorized spindle is the core functional component of high precision CNC machine tool, which has become the key research and development object of the world. Objective: By comparing and discussing the patents of high-speed motorized spindle, some valuable conclusions have been drawn to predict the future research and development of high-speed motorized spindle. Methods: By analyzing the characteristics of high-speed motorized spindle structure, the influence of high-speed motorized spindle on high-speed machining technology was explicated. Combining with the key technology of high-speed motorized spindle, the patents related to high-speed motorized spindle structure were used for investigation. Results: With the rapid development of high-speed cutting and numerical control technology and the need of practical application, the requirement for high-speed spindle performance has increased. Motorized spindle technology has the characteristics of high speed, high strength, high power, high torque and low speed, high precision, high reliability and long life, offering diversified bearing and lubrication cooling methods and serving as an intelligent system. Conclusion: The different levels of improvement and renovation of the structure with high-speed motorized spindle, by adding lubrication and cooling device to the spindle have improve the performance of spindle, addressing the loopholes in the technology and making it more practical.

Structure Design of Biaxial Rotary Milling Head with High-Torque, High-Precision and Mechanical Spindle

2014 ◽  
Vol 621 ◽  
pp. 337-345 ◽  
Author(s):  
En Ping Chen ◽  
Shao Hui Li ◽  
Feng He Wu ◽  
Chong Min Jiang
Keyword(s):  
High Precision ◽  
Structure Design ◽  
Worm Gear ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Loop Control ◽  
High Rigidity ◽  
Multi Stage ◽  
Timing Belt ◽  
Five Axis

As a key component of heavy five-axis linkage CNC machine tools, the existing mechanical biaxial rotary milling heads are usually driven by worm gear, timing belt, or multi-stage gears. Worm gear is inefficiency to transmit motion, hard to maintain the accuracy and difficult to eliminate all clearance; Timing belt can be seriously worn and cannot maintain good accuracy; and multi-stage gears transmission has defects such as long chain, low transmission stiffness. This paper aims at designing a biaxial rotary milling head with large output torque of 3000Nm, high precision and high rigidity. So a new design for biaxial rotary milling head with mechanical spindle, gear transmission and swinging fork structure is proposed. An integral supporting axis is applied to increase the rigidity of A-axis; through the closed numerical loop control based on precise encoder and the decoupling technology of feed motion of A/C axis, the contradiction between large reduction ratio and high precision transmission is solved, and then the requirement of high positioning accuracy (10") is met. Theoretical calculation and simulated analysis shown, the new design not only can guarantee transmission accuracy and dynamic characteristics of biaxial rotary milling head, but also can improve its structural stiffness and meet the high demands of large torque, high precision and high rigidity.

Computer Numerical Control Machine Tool and its Development Trend

2013 ◽  
Vol 774-776 ◽  
pp. 1458-1461
Author(s):  
Huan Yun Wang ◽  
Xiu Fen Liu
Keyword(s):  
Machine Tools ◽  
High Speed ◽  
Manufacturing Industry ◽  
High Reliability ◽  
Development Trend ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Control Machine Tool ◽  
Comprehensive Level

CNC machine tools are the key equipment in the equipment manufacturing industry, which is related to the national economic construction and strategic position, and is an important symbol reflecting the national comprehensive level. This article analyzes the emergency and characteristics of CNC machine tools and its development trend such as high precision, high speed, high reliability, complex, intelligent, flexibility, integration and openness.

Analysis of friction error in CNC machine tools based on electromechanical characteristics

2019 ◽  
Vol 233 (14) ◽  
pp. 4934-4946 ◽  
Author(s):  
Xiaoyong Huang ◽  
Xuesong Mei ◽  
Tao Tao ◽  
Lu Zheng ◽  
Dongsheng Zhang ◽  
...  
Keyword(s):  
Numerical Control ◽  
Cnc Machine Tools ◽  
Generation Process ◽  
Cnc Machine ◽  
Loop Control ◽  
Feed Drive ◽  
Feed Drives ◽  
Velocity Reversal ◽  
Analytical Formulas ◽  
Sliding Regimes

Friction is a kind of inherent and nonlinear disturbance in feed systems, which inevitably deteriorates motion accuracy at velocity reversal. Position error caused by friction is integrally effected by three aspects of feed drives, including command, control, and mechanical subsystems. Unfortunately, the traditional analyses hardly consider all mentioned aspects. Especially, no research has been reported on control characteristic at reverse motion. The purpose of this paper is to reveal the generation mechanism of friction error of a feed drive based on the commercial computer numerical control with three-loop control structure and velocity feedforward and proportional–proportional–integral controllers. Firstly, the generation process of the friction error at velocity reversal is profoundly investigated. Based on it, a simplified control model is conducted to explain transition from presliding to sliding regimes. It is the bond of analyzing friction error from command, control, and mechanical subsystems. Subsequently, the processes of presliding, acceleration, and adjustment stages are analyzed. Moreover, analytical formulas are derived to predict the durations of three stages and describe the shape of friction error. Then, the contour errors of linear and circular motion caused by friction can be predicted online. Experiments are introduced to verify the effectiveness of the proposed methods and formulations.

scholarly journals Study of Machining of Gears with Regular and Modified Outline Using CNC Machine Tools

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral
Keyword(s):  
Machine Tools ◽  
Coordinate Measuring Machine ◽  
Optical Microscope ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cylindrical Gears ◽  
Measuring Machine ◽  
Five Axis

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.

scholarly journals Practical method for the fast generation of a CAM model for jet engine parts

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110027
Author(s):  
Byung Chul Kim ◽  
Ilhwan Song ◽  
Duhwan Mun
Keyword(s):  
Computer Aided Design ◽  
Feature Recognition ◽  
Practical Method ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Jet Engine ◽  
Computer Aided ◽  
Cad Models ◽  
Cam Model

Manufacturers of machine parts operate computerized numerical control (CNC) machine tools to produce parts precisely and accurately. They build computer-aided manufacturing (CAM) models using CAM software to generate code to control these machines from computer-aided design (CAD) models. However, creating a CAM model from CAD models is time-consuming, and is prone to errors because machining operations and their sequences are defined manually. To generate CAM models automatically, feature recognition methods have been studied for a long time. However, since the recognition range is limited, it is challenging to apply the feature recognition methods to parts having a complicated shape such as jet engine parts. Alternatively, this study proposes a practical method for the fast generation of a CAM model from CAD models using shape search. In the proposed method, when an operator selects one machining operation as a source machining operation, shapes having the same machining features are searched in the part, and the source machining operation is copied to the locations of the searched shapes. This is a semi-automatic method, but it can generate CAM models quickly and accurately when there are many identical shapes to be machined. In this study, we demonstrate the usefulness of the proposed method through experiments on an engine block and a jet engine compressor case.

scholarly journals Dynamic Modeling and Experiment Research on Twin Ball Screw Feed System Considering the Joint Stiffness

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 686 ◽  
Author(s):  
Meng Duan ◽  
Hong Lu ◽  
Xinbao Zhang ◽  
Yongquan Zhang ◽  
Zhangjie Li ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Characteristics ◽  
Friction Model ◽  
Numerical Control ◽  
Ball Screw ◽  
Cnc Machine Tools ◽  
Axial Stiffness ◽  
Cnc Machine ◽  
Feed System ◽  
Lumped Mass

It is of great significance to study the dynamic characteristics of twin ball screw (TBS) feed system to improve the precision of gantry-type dual-driven computer numerical control (CNC) machine tools. In this paper, an equivalent dynamic model of the TBS feed system is established utilizing lumped mass method considering the stiffness of joints. Equivalent axial stiffness of screw-nut joints and bearing joints are both calculated by Hertz contact theory. Furthermore, a friction model is proposed because the friction force of the screw nut affects the stiffness of the joints. Then, the friction parameters are obtained by using the nonlinear system identification method. Meanwhile, a finite element model (FEM) is developed to assess the dynamic characteristics of TBS feed system under the stiffness of joints. Finally, validation experiments are conducted, and the results show that the positions of the nut and the velocities of worktable greatly affect the dynamic characteristics of the TBS feed system. Compared with the theoretical calculation, FEM and experiments indicate that the dynamic modeling proposed in this article can reach a higher accuracy.

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