On the synthesis of delay type controllers for tracking periodic reference inputs /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | Developed in this dissertation is a synthesis methodology for assuring asymptotic tracking of periodic reference inputs. The synthesis is accomplished by including a special delay element in the control loop. From servomechanism theory it follows that the inclusion of such a delay element could provide asymptotic tracking provided the resulting closed loop system can be stabilized. Hence, stability of such a loop becomes a key consideration. The closed loop stability issue of the delay control system is resolved by resorting to the Tsypkin locus or a circle type stability criterion. Both of these provide simple tests suited for practical design. It is confirmed that the stability of the delay system becomes a problem only when the plant being considered is strictly proper with the added requirement of zero steady state error. However, if one foregoes the requirement of zero steady state error for small steady state error the stability issue can be resolved in a reasonable manner. The basic design methodology is first developed for SISO systems and is extended to MIMO systems by converting the MIMO problem to a series of MISO problems. In doing so the loop interactions enter as disturbances on each loop. Also studied is the role of arbitrary small time delay in the control loop. It is observed that small time delays can give superior tracking results when compared to larger time delays called for in the theory. Also included is a discussion of how robustness considerations in MIMO systems can be handled using a simple time delay control. Included in the dissertation is an example of a 2 link robot manipulator made to track several difficult trajectories. The main contributions of this dissertation are (i) The development of a methodology for synthesizing delay type controllers for SISO systems based on a simple frequency domain stability test. (ii) The extension of the technique to MIMO systems by considering a series of MISO systems. (iii) The possible robustification of uncertain systems by incorporating small delay control. (iv) A proof of stability based on fixed point techniques that applies to a class of nonlinear systems. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Mechanical Engineering." |
| Physical Description: | xi, 135 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |