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Hovakimyan, Naira Hovakimyan, Naira Sha, Lui Voulgaris, Petros Salapaka, Srinivasa Jafarnejadsani, Hamidreza 2019-02-07T20:35:58Z 2019-02-07T20:35:58Z 2021-02-08T10:15:25Z 2018-11-21 2018-12 This dissertation extends the L1 adaptive control theory to sampled-data (SD) framework. Multi-input multi-output non-square (underactuated) systems are considered with different sampling rates for inputs and outputs. The sampled-data framework allows to address non-minimum phase systems, subject to less restrictive assumptions as compared to continuous time framework. It is shown that the closed-loop system can recover the response of a continuous-time reference system as the sampling time of the SD controller tends to zero. In this thesis, the L1 sampled data adaptive controller is integrated with the Simplex fault-tolerant architecture for resilient control of cyber-physical systems (CPSs). Detection and mitigation of zero-dynamics attacks are addressed and validated in flight tests of a quadrotor in Intelligent Robotics Laboratory of UIUC. The experiments show that the multirate L1 controller can e effectively detect stealthy zero-dynamics attacks and recover the stability of the perturbed system, where the single-rate conventional L1 adaptive controller fails. From the perspective of applications, the dissertation considers navigation and control of autonomous vehicles and proposes a two-loop framework, in which the high-level reference commands are limited by a saturation function, while the low-level controller tracks the reference by compensating for disturbances and uncertainties. A class of nested, uncertain, multi-input multi-output (MIMO) systems subject to reference command saturation, possibly with non-minimum phase zeros, is considered. Robust stability and performance of the overall closed-loop system with command saturation and multirate L1 adaptive controller are analyzed. Finally, a systematic analysis and synthesis method is proposed for the optimal design of filters in the L1 adaptive output-feedback structure, where the lowpass filter is the key to the trade-off between the performance and robustness of the closed-loop system. An optimization problem is formulated using the constraint on the input time-delay margin and a cost-function based on mixed L1/H2-norm performance measure. The optimization problem can be efficiently solved using linear/quadratic programming. We note that the framework of this dissertation and the multi-loop problem formulation of navigation and control of autonomous systems provide suitable synthesis and analysis tools for autonomous cyber-physical systems (CPSs), including self-driving cars, unmanned aerial vehicles (UAVs), and industrial/medical robots, to name just a few. The SD design facilitates the implementation of control laws on digital computers in CPSs, where the input/output signals are available at discrete time instances with different sampling rates. Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2020-12-01 The student, Hamidreza Jafarnejadsani, accepted the attached license on 2018-11-19 at 12:24. The student, Hamidreza Jafarnejadsani, submitted this Dissertation for approval on 2018-11-19 at 13:00. This Dissertation was approved for publication on 2018-11-21 at 10:30. DSpace SAF Submission Ingestion Package generated from Vireo submission #13099 on 2019-02-07 at 14:17:36 Made available in DSpace on 2019-02-07T20:35:58Z (GMT). No. of bitstreams: 2 JAFARNEJADSANI-DISSERTATION-2018.pdf: 5063483 bytes, checksum: ccbdbdfc53402870c30790cb341e0e6a (MD5) LICENSE.txt: 4221 bytes, checksum: 8f7b049ae365f0eda87fab60e9be56c4 (MD5) Previous issue date: 2018-11-21 Embargo set by: Seth Robbins for item 109822 Lift date: 2021-02-07T20:36:09Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Embargo set by: Seth Robbins for item 109822 Lift date: 2021-02-07T20:39:46Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Embargo set by: Seth Robbins for item 109822 Lift date: 2021-02-07T20:44:35Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system U of I Only Restriction Lifted for Item 109822 on 2021-02-08T10:15:25Z. application/pdf http://hdl.handle.net/2142/102798 en Copyright 2018 Hamidreza Jafarnejadsani cyber-physical security sampled-data systems multi-level multirate control L1 adaptive output-feedback control uncertain multi-input multi-output systems non-minimum phase systems zero-dynamics attack filter optimization Robust adaptive sampled-data control design for MIMO systems: Applications in cyber-physical security text text Mechanical Sci & Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.