Design and testing of piezoelectric-hydraulic actuators

Abstract

This paper describes design methodologies for construction of an actuator that uses smart materials to provide hydraulic fluid power. In the class of actuators described, hydraulic fluid decouples the operating frequency of the output cylinder from the drive frequency of the piezoelectric or other smart material. This decoupling allows the piezoelectric to be driven at high frequency, to extract the maximum amount of energy from the material, and the hydraulic cylinder to be driven at low frequencies to provide long stroke. However, due to fluid compressibility and structural compliance, the fundamental impedance match between the fluid and the piezoelectric make it difficult to convert energy from the piezoelectric into pressurized hydraulic fluid flow. The basic design tradeoffs and major technical issues are discussed in the areas of materials, mechanical design, and fluid-mechanical interface. Prototype devices and component measurements are presented. Test methods are described, and test results quantifying pump pressure and flow, and actuator force and velocity are summarized. The series of tests show the potential of these devices for high force long stroke devices powered by smart materials.

Large-Scale Piezoelectric-Based Systems for More Electric Aircraft Applications

“…The basic concept lies in coupling a piezoelectric stack with the transmission of hydraulic fluid via valve systems. The high frequency, large force, and small stroke of the piezoelectric actuator can be converted into a lower frequency and larger stroke of the output cylinder [ 141 , 142 , 143 , 144 , 145 , 146 , 147 ] ( Figure 14 a). Piezoelectric stacks can be operated by hundreds of volts, making it suitable for available electric power in aircraft.…”

Large flow rate/high frequency microvalve array for high performance actuators

“…piezoelectric materials and shape memory alloy) is increasing for space and military applications [1][2][3][4][5]. These hydraulic-based actuators often require high actuation frequencies to satisfy the large flow rate requirement.…”

Modeling and inverse compensation for giant magnetostrictive transducer applied in smart material electrohydrostatic actuator

“…Hydraulic control systems are used in aerospace and automotive industrial applications where high power density, high dynamic performance, robustness, and overload capability are desired (Karunanidhi and Sigaperumal, 2010; Li et al, 2011), but their need for hydraulic fluid lines can make them unsuitable for distributed actuation applications like those found on the unmanned combat air vehicle (UCAV) (Chaudhuri et al, 2009; Lindler and Anderson, 2003). The challenges are even greater in rotorcraft, as many of the important applications for noise and vibration control such as active flaps and active pitch links must operate in the rotating frame (John et al, 2009).…”