Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/36128
Title: Controlling Contour Errors in CNC Machines
Authors: HUO FENG
Keywords: Contour error, Error compensation, Taylor series expansion, Cross-coupled control, NARX neural network, Free-form curve
Issue Date: 22-Aug-2012
Source: HUO FENG (2012-08-22). Controlling Contour Errors in CNC Machines. ScholarBank@NUS Repository.
Abstract: In this thesis, various new approaches for reducing contouring errors in CNC machines are proposed. Through simulations and actual experimentations on a small two-axis CNC machine, these are shown to improve on existing approaches in reducing contouring errors. With perfectly known axial dynamics, the Taylor Series Expansion Error Compensation (TSEEC) approach is capable of achieving perfect contour following. However, it can only be used for linear and circular contours. A generalized TSEEC, or GTSEEC, is proposed here which extends its applicability to any arbitrary two-dimensional contours. A generalized cross-coupled control (GCCC) approach is also proposed which can be applied for any free-form contour, including those defined only by a series of (x, y) coordinates representing the reference position inputs in CNC machines. A new approach for contour error estimation based on NURBS interpolation (CEEBNI) is also developed for free-form contours. Finally, a NARX (Nonlinear autoregressive with exogenous inputs) network-based contour error reduction (NCER) approach is proposed and studied.
URI: http://scholarbank.nus.edu.sg/handle/10635/36128
Appears in Collections:Ph.D Theses (Open)

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