Integral feedback control of a self-sensing magnetostrictive actuator

摘要

An essential reason for the increasing interest in magnetostrictive materials is the capability to perform sensing and actuation at the same time and in the same place. With these inherent sensory capabilities, the material can adopt both sensing and actuation functions in mechatronic systems. Operating in this way, these solid-state transducers are frequently termed 'self-sensing actuators'. They support a miniaturized, simpler and cheaper mechatronic system design and are therefore regarded as a key technology in the 21st century. A central task in the development of the self-sensing magnetostrictive actuator was the separation of the sensing information from the actuation information contained in the magnetic flux measurement signal. In practice, however, due to the high input amplitudes undesired complex hysteresis and saturation nonlinearities appear, which make a separation of sensing information from actuation information with linear actuator models impossible. Therefore, a novel signal processing method based on hysteresis operators was applied to the self-sensing magnetostrictive actuator. This method allowed the compensation of these nonlinearities in real-time and with it a linearization and decoupling of sensor and actuator operation. The focus of the present paper is the combination of the operator-based signal processing concept with an integral feedback controller, which results in a so-called integral feedback controlled self-sensing magnetostrictive actuator. This control type is capable of compensating hysteresis effects as well as disturbances resulting from the limited actuator stiffness without the need for an external displacement or force sensor. The sensor information that is required by the integral feedback controller to guarantee the described functionality is gained solely via the inherent sensory properties of the actuator material. In this way, the integral feedback controlled self-sensing magnetostrictive actuator can be treated as an optimized component for positioning systems, vibration dampers and valve drives, for example in aeronautic and automotive applications.