Smart control of imperfect electromechanical systems

The concept of imperfection is always associated to a negative outlook. However, real devices are always imperfect and operate far from ideality. Despite this, real devices actually work. This is due to the fact that imperfections give rise to hidden dynamics, which can be excited to gain a positive effect on the overall behavior of the device. Human-machine systems are relevant examples of imperfect systems in which the presence of imperfections plays a crucial role, either negative or positive. In this paper, we focus on a paradigmatic example of imperfect systems, represented by a complex and imperfect electromechanical structure which supports and couples 15 coils rotating thanks to the electromagnetic interaction with associated magnets. The electrical and mechanical interaction between the coils and that between the coils and the structure generate complex patterns of vibration which may prevent the system from reaching the correct working conditions, i.e., all coils actually rotating. A control strategy to ensure coils rotation based on the excitation of the hidden dynamics induced by imperfections is discussed, characterizing its effect with respect to the control signal properties and to the power provided to the structure. It is worth to notice that the control strategy is essentially based on the excitation rather than on the suppression of the hidden dynamics, thus providing evidence on the possibility to control imperfect systems exploiting imperfections.