Miniaturized Gyroscope with Bearingless Configuration

One of the current topics in magnetic bearings technology is the exploration of their potential in the field of micro machines. Up to now in literature there are very few examples of realization and most of them are just experimental systems but it seems that further investigations can be performed. In this paper the evaluation of the performance of micro magnetic bearings in an application dealing with the navigation of planes and cars is reported. The realization of a miniaturized gyroscopic sensor based on active magnetic bearings (AMBs) is described from the mechanical to the control design. The mechanical and the actuation systems are analyzed along with the realization of the model and of two different control design strategies: a H(inf) and a decentralized MultiSISO control (a classical Proportional Derivative (PD) on each axis). For both the proposed approaches the modelling and the control design phases are discussed. The H(inf) strategy has been evaluated to perform a robust control and consists in a Plant Non-Inverting GS/T Weighting scheme with an explicit integral action and an anti wind-up action. In the case of decentralized strategy, the model of the system containing the transformation from the center mass coordinates to the actuators coordinates is exposed along with the tuning of the proportional and derivative actions. The numerical and experimental results obtained on the prototype with the two control strategies are compared to evaluate their behaviour in this application. Finally, the principle used to make the rotor spinning is exposed and the rotation results are discussed.