On event-based PI control of first-order processes

Abstract

Abstract:In this paper the design of an event-based proportional-integral (PI) control scheme for stable first-order processes is considered. A novel triggering mechanism which decides the transmission instants based on an estimate of the PI control signal is proposed. This mechanism addresses some sideeffects that have been discovered in previous event-triggered PI proposals, which trigger on the process output. In the proposed scheme, the classic PI controller is further replaced with PIDPLUS, a promising version of PI controller for networked control systems. Although PIDPLUS has been introduced to deal with packet losses and time delays, and, to the best of our knowledge, a stability analysis of the closedloop system where such a controller is used has never been performed, here the performance of such a controller in an event-based fashion are analyzed, and a stability analysis is further provided. The proposed event-based scheme ensures set-point tracking and disturbance rejection as in classic timeperiodic implementations of PI controller, while greatly reducing the number of sensor transmissions. The theoretical results are validated by simulations, where the benefits in using PIDPLUS in combination with the proposed PI event-based triggering rule are shown.

Actuator saturation and anti-windup compensation in event-triggered control

“…This behavior is caused by the sticking effect (Tiberi et al 2012;Vasyutynskyy and Kabitzsch 2006), where, in this case, the severe actuator saturation avoids further events after the second event time (indicated by the second star in the upper plot of the figure). As the state information used by the controller deviates from the operating point at that time instance, the controller state x c (t) increases monotonically for all future times.…”

“…Two general problems of event-triggered PID control are the sticking effect and large stationary oscillations (see Årzén 1999;Vasyutynskyy and Kabitzsch 2006). To overcome these problems two adaptations of the event-triggered control loop have been proposed by Tiberi et al (2012). By using a modified event condition based on the control inputũ(t) and by adapting the integrator part of the event-triggered PI-control loop considered, it has been shown that for stable first-order systems oscillations can be avoided and setpoint tracking is guaranteed.…”

Design of event-based PI-P controllers using interactive tools

“…In Sánchez, Visioli, and Dormido (2011) tuning rules arise from time-based approaches. In Tiberi and Johansson (2012) authors mention a specific tuning procedure for the PIDplus controller according to the methodology proposed in Otanez, Moyne, and Tilbury (2002) but its influence on system performance or stability is not described. In and tuning rules are defined using trialand-error methods with the aim of improving a performance index (typically, the energy consumption of wireless sensors).…”

PI control synthesis for event-triggered control systems

“…Few researchers address the setpoint tracking problem in the event-triggered control framework, see [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. An early approach of event-triggered PI control [7] has shown that the communication effort can be significantly reduced with little degradation of the control performance compared with the time-based counterpart.…”