Dynamic event-triggered control of nonlinear systems: a quasi-LPV approach

• Autor(a) principal: Pedro Henrique Silva Coutinho
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/41177
• topic: Networked control systems; Nonlinear systems; Event-triggered control; Linear matrix inequalities; Linear parameter varying systems; Engenharia elétrica; Desigualdades matriciais lineares; Sistemas não lineares

This thesis concerns the co-design of controllers and dynamic event-triggering mechanisms for the class of nonlinear networked control systems represented by polytopic quasi-LPV models. The main objective of this proposal is to derive co-design conditions, via LMIs, such that the number of generated events is reduced as much as possible. In particular, two dynamic event-triggering mechanisms are studied: the continuous and the periodic. In the case of dynamic continuous event-triggering mechanisms, a gain-scheduling control law is considered and the co-design conditions are developed based on the Lyapunov theory. In particular, the new proposed triggering law is such that it is possible to completely cancel out the effect of the asynchronous parameters since the controller's parameters are computed in terms of the state available from the triggering mechanism via the communication network. Then, based on the adequate treatment of the asynchronism effect, extra relaxations are considered to reduce the conservativeness of the LMI-based co-design conditions. Finally, it is proved that the proposed strategy does not lead to Zeno behavior. In the case of dynamic periodic event-triggering mechanisms, a new co-design condition is developed considering the Lyapunov-Krasovskii theory to ensure the stability of the closed-loop system with a linear control law. The effect of network-induced time delays is explicitly taken into account in the design. In both cases, as the design conditions are based on the locally equivalent quasi-LPV representation of the nonlinear plant, estimates of the region of attraction are obtained inside the compact region where the local representation is valid. Numerical simulations are presented to illustrate the effectiveness of the proposed co-design conditions to ensure the stability of the closed-loop system requiring a reduced number of events when compared to static triggering mechanisms designed via emulation and co-design.