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Modeling and Robust Stability of Advanced, Distributed Control Systems

Seitz, Timothy M
http://rave.ohiolink.edu/etdc/view?acc_num=osu1497201155817062

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
Many control system applications are undergoing a transition from digital control to networked control, similar to the transition from analog several decades ago. Networked control eases the process of utilizing information across distributed locations or other obstacles. Some industries that have begun to make use of networked control include automotive, aerospace, manufacturing, and internet based controllers. This dissertation draws specific motivation from the aerospace industry, where both geographic and size considerations are important considerations. Networked control systems (NCSs) have unique considerations that require further research, including delay, uncertainty, and bandwidth constraints. All three of these are addressed in this dissertation in addition to further control topics. First, in many previous papers, only a single delay has been considered in NCSs. This assumption ignores the distributed nature of sensors and actuators in a NCS, where there is likely an independent delay between the controller and each connected node. Delays are addressed in this dissertation by providing a new formulation that compactly models time-varying independent delays for each sensor and actuator. Second, uncertainty is addressed from the likely source, the continuous-time domain. Because NCSs interacting with physical systems are inherently sampled-data systems, model-based control generally starts with the continuous-time model. This dissertation considers a perturbation on the continuous-time plant model, bounding the size that still meets the performance specifications. Two different approaches are given. The first is robust stability that assumes the desired performance is for the system to be stable. To comprehensively address NCSs, several new theorems with a new extension allowing for time-varying systems, are presented for delay-free discrete-time systems and delay free, single lumped-delay, multiple delay (MD), and estimator compensated MD sampled-data systems. The approach is then generalized to allow for the user to define the performance by limiting the eigenvalues to an elliptical region in the complex plane, known as robust performance. Additional new theorems are presented for variations of NCS modelling. However, the time-variance is removed, because performance is based on eigenvalues. Third, bandwidth considerations are addressed by allowing for multiple sampling of sensors. Networks can only allow for a limited amount of transmissions. Therefore, it is beneficial to reduce the rate of certain sensors, which reduces the amount of bandwidth required for the NCS. In addition, advanced control techniques are addressed that take advantage of formulations presented in this dissertation. Namely, hierarchical control and a procedure for obtaining an optimized robust controller that accounts for MDs are discussed. Hierarchical control fits well into NCS formulations because it allows for remote connection of different subsystems, enabled by the network interface. The optimized control technique is shown to provide increased robust stability bounds, while not adversely affecting performance. Examples are shown throughout the dissertation based on a linear turbine engine model.
Rama Yedavalli (Advisor)
David Hoelzle (Committee Member)
Utkin Vadim (Committee Member)
Junmin Wang (Committee Member)
202 p.
Mechanical Engineering
Control; Networked Control Systems; Turbine Engines; Distributed Control; Multiple-delays; Muti-rate sampling; Robust stability; Robust D-Stability; Optimized robustness;

Recommended Citations

Citations

  • Seitz, T. M. (2017). Modeling and Robust Stability of Advanced, Distributed Control Systems [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1497201155817062

    APA Style (7th edition)

  • Seitz, Timothy. Modeling and Robust Stability of Advanced, Distributed Control Systems. 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1497201155817062.

    MLA Style (8th edition)

  • Seitz, Timothy. "Modeling and Robust Stability of Advanced, Distributed Control Systems." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1497201155817062

    Chicago Manual of Style (17th edition)

osu1497201155817062
566
© 2017, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.