A hybrid actuator basically consists of a piezoelectric and a magnetostrictive transducer oscillating in their resonant frequency. So the reactive energy is exchanged between both transducers, which leads to a high efficiency and a compact mechanical and electrical construction. Driven in its natural frequency, however, the strain-time characteristic of the hybrid actuator is always nearly sinusoidal; this restricts possible applications and therefore an extended performance was investigated by driving the actuator with signals different from a sinusoidal form. This contribution briefly reviews the basics of hybrid actuators and the oscillatory application in a linear motor. Then a hybrid relay is introduced as an example for quasi static operation. Based upon different drives enhanced strain-time characteristics of a hybrid stack actuator are theoretically and numerically predicted and verified by measurements. Finally, a method of detecting the external mechanical load by measuring the resonance frequency will be explained. This could be applied to the linear motor, which can be enabled to identify its load without an additional sensor.
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