Fractional-order modeling and control of ionic polymer-metal composite actuator

Abstract

Fractional-order (FO) calculus-based modeling and control of ionic polymer-metal composite (IPMC) actuators is studied in this paper. Since IPMC actuators exhibit FO dynamics, a suitable compensator must be designed for control thereof. In this work, we employ FO proportionalintegral-derivative (FOPID) controllers, as well as FO inverse model (FOINVM) based control. Only open-loop control methods are considered. Since process model-based control is used, the IPMC actuator is modeled using a FO transfer function, whereby a process identification is performed. Additionally, the designed controller is implemented in hardware that allows the whole control system to be easily miniaturized and considered in embedded applications. All of the experiments presented in this paper are carried out with the IPMC actuator placed in a controlled inert environment. The results of the real-time control experiments are presented and discussed and indicate the validity of the considered modeling and control approach.

Towards Industrialization of FOPID Controllers: A Survey on Milestones of Fractional-Order Control and Pathways for Future Developments

“…However, to ensure that FOPID controllers are ready for at-scale deployment to industrial applications, relevant research must also be conducted to establish the necessary technology readiness level (TRL) [37] of the developed control solutions. For example, in [38], TRL = 5 is achieved by confirming the performance of the tuned fractional-order controller in a series of experiments, thus confirming the reliability of the implemented control algorithm. More research is expected to be published further confirming the reliability of FOPID controllers and reaching greater TRL levels.…”

“…There is still a lack of such a type of rigorous research. It was recently verified in, e.g., [6], [38], that the technology suitable for actually physically implementing reliable FOPID controllers is readily available and that this technology stands against repeated laboratory tests. One important step for industrialization of FOPID control is clearly to move from laboratory experiments to actual field tests, i.e., to increase the TRL.…”

Challenges and Perspectives in Control of Ionic Polymer-Metal Composite (IPMC) Actuators: A Survey

“…In this case the methods of feedforward control or indirect estimation are employed. The feedfor-ward methods include the inversion-based control, applied to IPMC actuators in [32], [35]- [37], [43], [72]. The authors of [108] offered to estimate the IPMC position by means of an observer, developed for the nonlinear model from [107].…”

“…The application of fractional-order PID controllers to fractional-order models of IPMC was reported in [31] and [32]. Fractional-order models can describe more accurately memory-like characteristics of the IPMC material and fractional-order control methods are more effective than their conventional integer-order counterparts.…”

A fractional order model for electrochemical impedance of IPMC actuators based on constant phase element

“…Some works concerning the modeling of IPMC with fractional order approaches have also been reported. For instance these works include investigating the bending behavior (Caponetto et al, 2008;, relation between the input and output voltage (Caponetto et al, 2013) and position tracking control (Caponetto et al, 2015;Tepljakov et al, 2019). In these cases the flexibility of fractional order modeling is obvious however there is no physical interpretation for them.…”