Piezomotors using flexure hinged displacement amplifiers

The design and construction of two different piezomotors developed by the authors is briefly described. Both employ flexure hinged mechanical displacement amplifiers to increase the output movement of stack-type piezoelectric actuators to enable them to be applied to rotation generating mechanisms. The first example is a harmonic piezomotor. The harmonic drive principle enables the production of an externally commutated motor which can be driven as a conventional stepping motor for open-loop applications and which yields a very fine rotational increment. The use of piezoelectric actuators makes the motor power consumption almost zero in holding situations, which gives it an advantage over conventional electromagnetic motors in some applications. The second prototype piezomotor presented is based on a roller clutch mechanism. Using one, or more, piezo-stack actuators and a roller clutch as the rotational motion converter, this motor has a very simple structure and requires only a single phase power input. To achieve effective movement of the motor using commercial tolerance roller clutches, the output movement of the piezo-stacks is again magnified by flexure hinged displacement amplifiers