1,265 research outputs found
Inversion-based set-point filter design for fractional control systems
No full textIn this paper we propose a novel approach to design a set-point filter based on a dynamic inversion technique. First, a suitable command signal is designed in order to obtain a smooth monotonic output transition. Then, a set-point filter is determined based on the synthesized command signal. The filter is computed by minimizing the 2-norm difference between the command signal and the filter step response. The proposed approach is suitable for the design of two degree-of-freedom control systems because the set-point tracking performance is independent from the chosen feedback controller. Simulation results prove the effectiveness of the proposed methodology
Inversion-based feedforward design for constrained fractional control systems
No full textIn this paper we propose an input-output inversion-based methodology for the synthesis of the feedforward action for a fractional control system in order to achieve a predefined process variable transition from a steady-state value to another. In particular, the feedforward action is implemented either as a signal to be added to the feedback control variable or as a command signal to be applied (instead of the typical step signal) to the closed-loop system. The method allows the minimization of the transition time by taking explicitly into account constraints on the process input an output and their derivatives. Simulation results show the effectiveness of the technique
Tuning rules for optimal PID and fractional-order PID controllers
No full textIn this paper we present a set of tuning rules for standard (integer-order) PID and fractional-order PID controllers. Based on a first-order-plus-dead time model of the process, the tuning rules have been devised in order to minimise the integrated absolute error with a constraint on the maximum sensitivity. The achieved performance indexes can also be used for the assessment of the controller performance. Both set-point following and load disturbance rejection tasks are considered. By comparing the results obtained for the two kinds of controllers, it is shown that the use of fractional-order integral action is not advantageous, while the use of a fractional-order derivative action provides a performance improvement
A General Design Methodology for Fractional Cascade Control Systems
No full textIn this paper we propose a design methodology for a cascade control system where the two controllers are of fractional-order-proportional-integral-derivative type. The tuning of the inner (secondary) controller aims to achieve a high performance (in terms of the integrated absolute error) in the load disturbance rejection task by exploiting the fractional-order derivative action. Then, a fractional-first-order-plus-dead-time transfer function of the inner feedback system in series with the primary process is estimated and the outer (primary) controller is tuned to maintain performance in rejecting load disturbances while achieving a satisfactory set-point response. Simulation results show the effectiveness of the methodology and the key role played by the additional flexibility in the design introduced by the fractional-order controllers
Optimal tuning of ideal fractional-order PID controllers for FOPDT processes.
No full textIn this paper we present a set of optimal tuning rules for fractional-order proportional-integral-derivative controllers applied
to (self-regulating) first-order-plus-dead-time processes. In particular, the proposed tuning rules aim at minimizing the integrated absolute error with a constraint on the maximum sensitivity in order to provide the required level of robustness.
Both the set-point following and load disturbance rejection tasks are considered. The achieved performance is compared with that obtained by using FOPID controllers in series form. Simulation
results confirm the obtained results
Optimal feedback/feedforward control of fractional FOPDT uncertain systems
No full textIn this paper a combined feedback/feedforward design methodology is proposed in order to cope with model uncertainty
and to minimize performance degradation. Based on a fractional commensurate uncertain model, a parametric robust controller is first designed. Then, a parametric command signal for the unity
feedback loop is designed. Finally, the optimal set of parameters is found by solving a constrained min-max optimization problem in order to minimize the worst-case settling time. Simulation results show the effectiveness of the methodology
Laboratorio di Automatica: Modellazione, Osservazione e Controllo di un Sistema Meccatronico
No full textNella dispensa viene descritta un'esperienza di laboratorio che mette in particolare risalto il ruolo della progettazione del sistema di controllo nell'ambito di un sistema meccatronico. In particolare, viene considerato il controllo del moto di un servosistema con trasmissione elastica, ovvero composto da un motore in corrente continua con riduttore collegato a un volano attraverso una molla torsionale
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