Lian Xia

A new electronic gearbox for gear hobbing machines

This article presents a new kind of software-defined electronic gearbox for gear hobbing based on a theoretical model of the hobbing process. The electronic gearbox implementation and structure are studied in an embedded numerical control system (numerical control/computer numerical control). Data flow among the electronic gearbox modules is also analyzed in the numerical control system. Special G-codes with parameters are designed, and the electronic gearbox control implemented through numerical control programming is realized in a custom gear hobbing numerical control system. In addition, two different hobbing methods (axial and diagonal) are tested on the computer numerical control platform. Results show that the hobbing computer numerical control with the proposed electronic gearbox functions accurately, and error is measured using tracking errors in different axes and gear pitch error of the machined gear. As will be shown, the gear pitch error was found to be 0.0147 mm for axial hobbing and 0.0176 mm for diagonal hobbing.

External high-order multistage modified elliptical helical gears and design procedure of their gear pairs

In view of the limited quantity of modified segments for high-order and two-stage modified elliptical helical gears, and poor adjustment capacity for transmission ratio, the formation mechanism of a high-order multistage modified ellipse was studied, and a unified mathematical expression of the family of ellipses was derived. Thus, a design procedure for the helical gear pairs of the high-order multistage modified ellipse was suggested, and then their transmission characteristics were discussed exhaustively. Moreover, some checking methods such as curvature radius of pitch curve, convexity, pressure angle, undercutting, and contact ratio were offered. Finally, two design cases, including two-order and three-stage modified elliptical helical gear pair and two-order and four-stage one, were implemented. The cases indicate that a high-order multistage modified elliptical helical gear can be utilized in practice.

Research on Non-Circular Gear Hobbing Simulation Based on Piecewise Cubic Spline Fitting

In order to solve the hobbing machining data calculation and hobbing simulation of non-circular gear with various shapes, the piecewise cubic spline fit method has been adopted to unify the polar coordinate expression of non-circular pitch curve. The method to generate hobbing machining data was deduced based on hobbing linkage mathematical model, and the machining data error caused by piecewise cubic spline fitting method was analyzed. The three-dimension software has been used as simulation tool to make secondary development, and then non-circular gear hobbing simulation was realized based on machining data, which can verify the validity of machining data and the relevant design drawbacks of non-circular gear. The work of this paper lay a good foundation for design parameters optimization and hobbing of non-circular gear.

Modeling and adaptive compensation of tooth surface contour error for internal gearing power honing

The machining of high precision gears requires a strict and accurate co-movement relationship controlled by the electronic gearbox between the moving axes of the gear machine tools. This article proposes a tooth surface contour error modeling method and an adaptive electronic gearbox cross-coupling controller for internal gearing power honing. First, the electronic gearbox model is structured according to the generative machining principle of internal gearing power honing and the tooth surface contour error is established by means of homogeneous coordinate transformation and meshing principle. Then, the adaptive electronic gearbox cross-coupling controller is designed, which comprises the electronic gearbox cross-coupling controller and the fuzzy proportional–integral–derivative controllers whose universes of membership functions in fuzzy rules are optimized by particle swarm optimization to improve the adaptability and robustness to disturbance fluctuation and model uncertainty of the system. Finally, experiments are carried out on a self-developed gear numerical control system. The results have demonstrated that the estimated tooth surface contour error using the proposed method is very close to the actual one, and the proposed adaptive electronic gearbox cross-coupling controller can effectively reduce the tracking error and the tooth surface contour error when compared to the electronic gearbox cross-coupling controller and non–electronic gearbox cross-coupling controller (electronic gearbox controller without cross-coupling and adaptive compensation).

Mechanism study on gear tooth surface texture in power honing process

Gear driving occupies an indispensable position in the field of mechanical transmission of the modern industry, better texture and mechanics characteristics of gear surface contribute to better meshing quality. Gear honing has been wildly used as gear finishing process because of its better gear surface texture and higher surface residual stress than gear grinding in recent years, especially for the development of power honing with internal gearing. In this paper, the gear surface model of the bull-gear in gear box was built based on the involute helicoid theory, and then the points of gear surface were converted to the honing wheel by using the space coordinate transform theory and matrix resolution method, the tooth surface model of the honing wheel was calculated based on the honing parameters and the conjugate contact principle of internal meshing. Through analysing the relative motion velocity vector of contact lines, the formation mechanism of gear surface texture was reflected clearly with different axis-crossing angles. The results of this research have important theoretical and instructional significance for the honing process. [Received 22 July 2016; Accepted 16 November 2016]

Linear Motor Control Algorithm and Experimental Research Based on Feedforward Fuzzy PID

In this paper, theory analysis, the MATLAB research and experimental verification about feedforward fuzzy PID control have been performed by combining the characteristics of the PID, feedforward control and fuzzy control. Simulation results show that the feedforward fuzzy PID control could improve the response speed of the system and reduce the tracking error of the system which shows the obvious superiority compared with the PID, feedforward PID, and fuzzy PID. Load experiment for such four kinds of control modes is done on the linear motor platform, and the experimental results show that the accuracy of the feedforward fuzzy PID control is obviously higher than the other three kinds of control modes and the feedforward fuzzy PID control is easier to be implemented. The position error of feedforward fuzzy PID control is changeless during the load change, and the change of the speed tracking error is small, which proves that the feedforward fuzzy PID control is suitable for the condition of load change or the great disturbance.

External High-Order Multistage Modified Elliptical Helical Gears and Design Procedure of Its Gear Pair

In view of the limited number of the modified segments for high-order and two-stage modified elliptical helical gears, and poor adjustment capacity for gear ratio, the formation mechanism of a high-order multistage modified ellipse was studied, and a unified mathematical expression of the family of ellipses was obtained. Thus, a design procedure for the helical gear pair of the high-order multistage modified ellipse was suggested, and its transmission characteristics were discussed exhaustively. Moreover, some checking methods such as the curvature radius of the pitch curve, convexity, pressure angle, root cutting, and contact ratio were offered. Finally, two design cases, including two-order and three-stage modified elliptical helical gear pair and two-order and four-stage one, were implemented. The cases indicate that a high-order multistage modified elliptical helical gear can be utilized in practice.Copyright

Research and Implementation of Multi-Threading Technology on Embedded Hobbing CNC

The embedded hobbing CNC is designed,which is embedded in the WinCE 5.0 operating system,on the hardware platform of ARM+DSP+FPGA ,using Embedded Visual C++(EVC) as a development tool. Hobbing CNC achieves the concurrent operation on the application in order to realizes parallel processing of multi-task, such as the HumanComputer Interaction, data acquisition and issued, data processing and analysis, data storage and so on, based on the analysis of hobbing CNCs working principle, using the multi-threading technology and thread synchronization mechanism possessed by WinCE 5.0. The application simplifies the complexity of the applications development and facilitates subsequent functions improvement, using modular programming method and the object-oriented design. This article provides an effective solution for multi-threaded application in hobbing CNC. After preliminary validation of testing experiments, the hobbing CNC has strong real-time and stability, and can realize the applications real-time and stability required by hobbing CNC machining.

Key Technologies of Embedded Gear Machining CNC System

A reconfigurable gear machining numerical control system (NC/CNC) architecture is proposed in this paper. The CNC platform can be quickly applied to gear hobbing, shaping, milling and grinding machine, through simple reconfiguring or parameter setting. Parametric automatic programming technology, high speed and high precision electronic gearbox, process database technology are studied. Based on the analysis of the gear machining process, the mathematic model on automatic programming of gear machining is established. Based on the Windows CE operating system, the CNC gear machining automatic programming system is developed on the ARM+DSP hardware platform, including the design of human-machine interface, automatic programming algorithm and other modules. With the support of the automatic programming and process database modules, NC codes can be generated automatically just by inputting gear parameters, tool parameters and process parameters, then, the interpolation data structure can be generated by interpreter module. A new kind of software electronic gearbox (EGB) and its implementation methods are also researched in the embedded CNC. Data flow among the modules is analyzed. Finally, experiments are conducted, and the tracking error and contour error are analyzed. The results show that the proposed gear machining CNC architecture is effective.Copyright