Browsing by Author "Pan, Yi-Ren"

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A New Framework of Disturbance Observer with Vidyasagar's Structure
(2018-12-01)
Chen, Yu-Xian
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Huang, Ruei-Yu
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Chang, Shih-Chung
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Pan, Yi-Ren
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Lee, An-Chen
This paper proposes a novel two degree of freedom (TDOF) control structure: a combination of Vidyasagar's structure (VS) and the doubly coprime factorization based disturbance observer (DCFDOB). The DCFDOB-VS framework is aimed at providing a control structure and design procedure for a MIMO system with good characteristics of disturbance attenuation, tracking, and decoupling property. The structure can deal with stable/unstable and minimum phase/non-minimum phase plants. The advantage of the method is that two parameters can be designed for different purposes, independently. The parameter H stabilizes the system and improves tracking property. Once the parameter H has been designed, then the Q(Y) can be implemented via a parameter Q for rejecting disturbances and improving the system robustness.
Advanced parameter identification for a linear-motor-driven motion system using disturbance observer
(2009-10-01)
Pan, Yi-Ren
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Shih, Yi-Ti
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Horng, Rong-Hwang
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Lee, An-Chen
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機械工程學系
Disturbance observer (DOB) is generally introduced into motion control systems to eliminate undesired disturbances and plant uncertainty. The DOB is also used for system identification. This work presents a novel experimental identification algorithm using disturbance observer to identify inertia, viscous coefficient, and friction of linear-motor-driven motion system. A conventionally adopted algorithm for determining the inertia of the motion system based on orthogonal relations among system responses is modified and extended to estimate the viscous coefficient and the magnitude of Coulomb friction of the underlying system. The advantages of the proposed method are high convergence rate and only one experiment needed to evaluate the system parameters. The proposed algorithm is demonstrated to be workable by both simulation and experiment.
Output Disturbance Observer Structure Applied to Run-to-Run Control for Semiconductor Manufacturing
(2011-02-01)
Lee, An-Chen
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Pan, Yi-Ren
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Hsieh, Ming-Tsung
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機械工程學系
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Department of Mechanical Engineering
Among the run-to-run (RtR) controllers, the EWMA controller, the double EWMA controller, and the predictor corrector controller are widely adopted in the semiconductor industry. This paper presents a unified framework for these controllers, which is called the output disturbance observer (ODOB) structure. The advantages of applying the ODOB structure are that the process output will be forced to the process target and the actual plant to the nominal plant while the process disturbance and the measurement noise are rejected. The relations of the tuned parameters of the above-mentioned controllers and the ODOB controller are discussed. Furthermore, based on the unified framework, the RtR controller with model mismatch and metrology delay can be analyzed systematically. In this paper, we analyze the robust stable conditions for the ODOB controller taking the model mismatch and metrology delay into consideration and provide a method to tune the controller.
Robust observer-controller compensator design using the loop shaping design procedure and the algebraic method
(2010-07-10)
Lee, An-Chen
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Pan, Yi-Ren
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Huang, Yuan-Yong
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機械工程學系
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Department of Mechanical Engineering
This paper investigates robust observer-controller compensator design using Vidyasagar's structure (VS). VS has a unit matrix parameter H similar to the Q parameter for the Youla-Kucera parameterization. VS can be designed based on the left coprimeness of the central controller in the H(infinity)-loop shaping design procedure (H(infinity)-LSDP) and therefore can preserve the intrinsic properties of the H(infinity)-LSDP. This paper introduces algebraic methods to simplify the design of H in the VS controller by solving specific algebraic equations. In particular, the algebraic design of H can achieve two things. First, a dynamic H adjusts the tracking performance and yields the integral action. Second, a dynamic H rejects the input and output sinusoidal disturbances with known frequencies. These attributes are indications of the flexibility of the proposed method since the output-feedback controller design of the H(infinity)-LSDP cannot easily deal with such conditions. This paper discusses the achieved loop and the closed-loop behavior of the system with VS, and also gives two numerical examples. The first example shows that the proposed method results in a better design in many aspects than the resulting from H(infinity)-LSDP. The second example shows the application of the proposed method to rejecting input and output step disturbances, and input and output multiple sinusoidal disturbances, for which the H(infinity)-LSDP can hardly be used. Copyright (C) 2009 John Wiley & Sons, Ltd.
The feedrate scheduling of NURBS interpolator for CNC machine tools
(2011-06-01)
Lee, An-Chen
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Lin, Ming-Tzong
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Pan, Yi-Ren
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Lin, Wen-Yu
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機械工程學系
This paper proposes an off-line feedrate scheduling method of CNC machines constrained by chord tolerance, acceleration and jerk limitations. The off-line process for curve scanning and feedrate scheduling is realized as a pre-processor, which releases the computational burden in real-time task. The proposed method first scans a non-uniform rational B-spline (NURBS) curve and finds out the crucial points with large curvature (named as critical point) or G(0) continuity (named as breakpoint). Then, the NURBS curve is divided into several NURBS sub-curves using curve splitting method which guarantees the convergence of predictor corrector interpolation (PCI) algorithm. The suitable feedrate at critical point is adjusted according to the limits of chord error, centripetal acceleration and jerk, and at breakpoint is adjusted based on the formulation of velocity variation. The feedrate profile corresponding to each NURBS block is constructed according to the block length and the given limits of acceleration and jerk. In addition, feedrate compensation method for short NURBS blocks is performed to make the jerk-limited feedrate profile more continuous and precise. Because the feedrate profile is established in off-line, the calculation of NURBS interpolation is extremely efficient for CNC high-speed machining. Finally, simulations and experiments with two free-form NURBS curves are conducted to verify the feasibility and applicability of the proposed method. (C) 2011 Elsevier Ltd. All rights reserved.