No abstract

While piezoelectric actuators are very useful for high frequency applications, their small strokes pose a significant constraint to most applications. Internally leveraged amplification schemes overcome this constraint, but at the cost of output force and bandwidth. The telescopic actuation architecture employs a novel internal amplification scheme that provides a moderate stroke amplification (up to 20 times) while maintaining high force and bandwidth. This paper presents a study of the dynamic behavior of this generic type of actuation. Because of the complexity of the structure, a new modeling technique based upon adaptation of the transfer matrix method was developed. As validation, a three cylindrical PZT5H telescopic actuator was fabricated and experimentally tested.

In the use of piezoelectric actuators, it is a clear choice to use stack (or d 33 mode) architectures when very high force is required or bender (or d 31 mode) architectures when very high displacements are needed. However, the choice isn't as clear for applications that need simultaneously moderate to high force and displacement. This paper presents one such application, INSTAR, which is posed with this dilemma. INSTAR is a novel rifle system that has an inertially stabilized barrel via an active suspension based on piezoelectric actuation. While the frequency required for this application was low (~10Hz), the displacement (± 200 to 400 microns) and the force (22-45 N) are moderate. Two very different actuation approaches were developed, modeled, fabricated and experimentally validated within the INSTAR demonstration platform: 1) a d 31 approach based on the Recurve architecture with focus on generating higher forces than is common for d 31 actuators and 2) a d 33 approach based upon a compliant mechanism designed using topology optimization with focus on providing more amplified strain than is common for d 33 actuators. Both approaches were successful in meeting the INSTAR requirements, but each had its own advantages and disadvantages.