Tuning rules for unstable dead-time processes

Rodrigues, Rejane C. Sá; Sombra, Andresa Kelly Ribeiro; Torrico, Bismark C.; Pereira, René D. O.; Forte, Marcus Davi do Nascimento; Filho, Magno Prudêncio de Almeida; Nogueira, Fabrício G.

doi:10.1016/j.ejcon.2020.10.001

Cited by 12 publications

(15 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unlike the situation without a filter, where it was possible to choose arbitrarily the tuning parameter D c in Equation (11), the "optimal" controller gain (16) now depends on the filter parameters n and λ.…”

Section: Filtered P Controller Designmentioning

confidence: 99%

“…DTCs with plant stabilization via the setpoint tracking channel [19,20,35,36,45,46] existed before the first FSP control solutions and their modifications to integrating and unstable systems. In some of published FSP concepts [16,[47][48][49][50][51][52][53][54][55], the insufficient attention is paid to the alternative solutions, which yield comparable, or even better results than those offered by the FSP control.…”

Section: State-space Based Dtc Design In the Discrete-time Domainmentioning

confidence: 99%

“…As for the illustration of the discussed controllers by real-time control, we do not know of an available unstable system with dominant first-order dynamics, which would allow safe experimentation in a laboratory environment. The unstable robotic arm used in the article [16] rather represents a system with unstable second-order dynamics that, in general, requires at least two pulses in the control signal course (corresponding to acceleration and braking), which should be respected in evaluating its dynamics (see, e.g., [10]). We will return to it when designing the corresponding controllers.…”

Section: Illustrative Example-temperature Controlmentioning

confidence: 99%

“…Therefore, its extension to integrating and unstable systems is still the goal of current research. However, in addition to the further development of FSPs [14][15][16], DTCs for unstable and integrating systems can also be designed as stabilized solutions that still provide the disturbance signal, which is important for many applications. The stabilizing controller designed correctly for an unstable plant can first yield a stable circuit with known dominant dynamics, for which we then propose a disturbance observer in the usual way [17].…”

Section: Introductionmentioning

confidence: 99%

“…The second aim is to analyse in details all significant features of the discrete-time Smith predictor inspired solutions applied possibly also to unstable and integral plants [14,[16][17][18]21,22]. This, however, requires elimination of the unstable plant mode from the disturbance response and also elimination of the disturbance signal from the controller structure.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Dead-Time Compensation for the First-Order Dead-Time Processes: Towards a Broader Overview

et al. 2021

View full text Add to dashboard Cite

The article reviews the results of a number of recent papers dealing with the revision of the simplest approaches to the control of first-order time-delayed systems. The concise introductory review is extended by an analysis of two discrete-time approaches to dead-time compensation control of stable, integrating, and unstable first-order dead-time processes including simple diagnostics of the model used and focusing on the possibility of simplified but reliable plant modelling. The first approach, based on the first historically known dead-time compensator (DTC) with possible dead-beat performance, is based on the reconstruction of the actual process variables and the compensation of input disturbances by an extended state observer (ESO). Such solutions play an important role both in a disturbance observer (DOB) based control and in an active disturbance rejection control (ADRC). The second approach considered comes from the Smith predictor with two degrees of freedom, which combines feedforward control with output disturbance reconstruction and compensation by the parallel plant model. It is shown that these two approaches offer advantageous properties in the case of actuator limitations, in contrast to the commonly used PID controllers. However, when applied to integrating and unstable first-order systems, the unconstrained and possibly unobservable output disturbance signal of the second solution must be eliminated from the control loop, due to the hidden structural instability of the Smith predictor-like solutions. The modified solutions, usually referred to as filtered Smith predictor (FSP), then no longer provide a disturbance signal and thus no longer fully fit into the concept of Industry 4.0, which is focused on further optimization, predictive maintenance in dynamic systems, diagnosis, fault detection and fault identification of dynamic processes and forms the basis for the digitalization of smart production. Nevertheless, the detailed analysis of the elimination of the unstable disturbance response mode is also worth mentioning in terms of other possible solutions. The application of both approaches to the control of a thermal process shows almost equivalent quality, but with different dependencies on the tuning parameters used. It is confirmed that a more detailed identification of the controlled process and the resulting higher complexity of the control algorithms does not necessarily lead to an increase in the resulting quality of the transients, which underlines the importance of the simplified plant modelling for practice.

show abstract

Section: Filtered P Controller Designmentioning

confidence: 99%