Synthesis of controllers for non-minimum phase and unstable systems using non-sequential MIMO quantitative feedback theory /
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| Format: | Thesis eBook |
| Language: | English |
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[College Station, Tex.] :
[Texas A&M University],
[2005]
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| Online Access: | Link to OAK Trust copy |
| Abstract: | Considered in this thesis is multi-input multi-output (MIMO) systems with non-minimum phase (NMP) zeros and unstable poles where some of the unstable poles are located to the right of the NMP zeros. In the single-input single-output (SISO) case such systems pose serious difficulties in controller synthesis for performance and stability. In spite of the added degrees of freedom the MIMO case also poses difficulties as has been experienced in the stabilization of the X-29 aircraft. When using the MIMO QFT technique the synthesis of the multivariable problem starts by considering the diagonal entries, (P⁻¹)[subscript]ii=1/q[subscript]ii, derived from the plant transfer matrix P that are used to develop a controller. In effect the design problem is reduced to several MISO designs with the diagonal entries of as the equivalent SISO plants. Developed iin this thesis is a transformation scheme that can be used to condition the resulting equivalent SISO plants so that the difficult problem of NMP zeros lying to the left of unstable poles is avoided. It is accomplished by introducing two transformations matrices M, N so that a new plant P₁= M⁻¹ PN, and a controller G₁=N⁻¹GM, where entries of both M, N can be either constants or polynomials of s. Thus it is proposed that P₁ be used instead of the original plant P when carrying out a MIMO QFT design. For example, if we have unstable poles or NMP zeros in q[subscript]ii obtained from P we can define a new set [g[subscript]ii where each [q^[subscript]ii has a desirable stable and/or minimum phase (MP) structure. All that one has to do then is, if feasible, to determine non-singular matrices M and N such that P⁻¹₁=N⁻¹P⁻¹M and (P⁻¹₁)[subscript]u=1/q^[subscript]ii Examples illustrate the use of the proposed transformation. |
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| Item Description: | "Major Subject: Mechanical Engineering" Title from author supplied metadata (automated record created on Sep. 21, 2005.) Vita. Abstract. Electronic resource. |
| Format: | Mode of access: World Wide Web. System requirements: World Wide Web access and Adobe Acrobat Reader. |
| Bibliography: | Includes bibliographical references. |