Investigation of Active Materials as Driving Elements in a Hydraulic-Hybrid Actuator

Abstract

In recent years, there have been growing applications of smart materials, such as piezoelectrics and magnetostrictives, as actuators in the aerospace and automotive fields. Although these materials have high force and large bandwidth capabilities, their use has been limited due to their small stroke. The use of hydraulic amplification in conjunction with motion rectification is an effective way to overcome this problem and to develop a high force, large stroke actuator. In the hybrid-hydraulic concept, a solid-state actuator is driven at a high frequency to pressurize fluid in a pumping chamber. This paper presents a comparison of a piezostack, Terfenol-D, and Galfenol element as the driving material in a hybrid-hydraulic actuator. The performance of the actuator with the various driving elements is measured through systematic testing and compared based on input power.