Dissertation/Thesis Abstract

System identification and robust control of a high-precision computer numerical controlled machine
by Sanders, Robert W., M.S., California State University, Long Beach, 2015, 60; 1603105
Abstract (Summary)

Modeling a feed axis of a Computer Numerical Controlled (CNC) machine is a challenging problem due to its time-varying dynamics and parametric uncertainties. A simple but practical system identification method was proposed in this thesis and combined with the H∞ technique to design a robust controller for a high-precision CNC milling machine. The ballscrew driven worktable of a Southwestern Industries 2OP Mill was modeled by means of a standard frequency response test. The model was linearized around the first axial resonance, and then used to synthesize an H∞ controller based on the linear matrix inequality approach. The simulated closed-loop system was subjected to disturbances and to a reference tool path to test its disturbance rejection and command following capabilities. Another simulated closed-loop system based on the machine’s actual Proportional-Integral-Derivative (PID) controller was created and subjected to the same tests in order to compare the performance of the two controllers. In all simulations, the H∞ controller displayed better performance than the PID controller.

Indexing (document details)
Advisor: Lu, Bei
Commitee: Gao, Qingbin, Marayong, Panadda
School: California State University, Long Beach
Department: Mechanical and Aerospace Engineering
School Location: United States -- California
Source: MAI 55/02M(E), Masters Abstracts International
Subjects: Mechanical engineering
Keywords: Computer numerical control, Linear matrix inequality, Robust control
Publication Number: 1603105
ISBN: 978-1-339-20550-2
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