Browsing Dept. of Mechanical Engineering - Ph.D. / Sc.D. by Author "Tohidi, Seyed Shahabaldin"
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Item Open AccessAdaptive control of cyberphysical human systems(Bilkent University, 2021-08) Tohidi, Seyed ShahabaldinThis dissertation focuses on the control of cyberphysical human systems in the presence of actuators’ redundancy and constraints. A novel adaptive control tech-nique is proposed to allocate control signals among redundant actuators in the presence of uncertainty and actuator saturation. The proposed method does not require any uncertainty identiﬁcation or persistency of excitation assumption. The stability of the proposed method is guaranteed using Lyapunov stability analysis. In addition, a modiﬁed projection operator that can be implemented to the adaptive control allocation is proposed. This operator enables the allo-cator to handle both magnitude and rate limits of actuators. A novel sliding mode controller with time-varying sliding surface is designed to complement the adaptive allocator and guarantee stability and reference tracking in the presence of uncertainty and actuator saturation. This controller is robust to both adap-tive control allocation error and external disturbance. Furthermore, an adaptive human model is proposed to mimic the human control response in the presence of uncertainty. The proposed structure is based on the model reference adaptive control, and the adaptive laws are obtained using the Lyapunov-Krasovskii stabil-ity criteria. To validate this model, an experimental setup is employed to collect data and a statistical analysis is conducted to measure the predictive power of the pilot model. Finally, the stability limits of a human-in-the-loop closed loop control system, where the plant to be controlled has redundant actuators with uncertain dynamics, are demonstrated. Various human models with and without time delays are investigated. Simulation results are provided to demonstrate the eﬀectiveness of the proposed methods in each chapter.