Design Model for Piezohydraulic Actuators

Regelbrugge, Marc E.; Lindler, Jason E.; Anderson, Eric H.

doi:10.2514/6.2003-1640

Cited by 13 publications

(16 citation statements)

References 5 publications

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“…More recent models capture additional fluid losses and predict performance more accurately. 11 Future versions of the device will attempt to double both the velocity output and the force output, more than quadrupling total output power.…”

Section: Device Level Tests and Resultsmentioning

confidence: 99%

Design and testing of piezoelectric-hydraulic actuators

Lindler¹,

Anderson²,

Regelbrugge³

2003

SPIE Proceedings

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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.

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Section: Device Level Tests and Resultsmentioning

confidence: 99%

Design and testing of piezoelectric-hydraulic actuators

Lindler¹,

Anderson²,

Regelbrugge³

2003

SPIE Proceedings

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“…For small piston displacements, the pressure generated within the pumping chamber is a linear function of the fluid bulk modulus, b, as follows (Regelbrugge et al, 2003;Tan et al, 2005;Chaudhuri et al, 2009):…”

Section: Preliminary Designmentioning

confidence: 99%

“…The authors noted that a model of the valves should include reverse motion for more accurate representation. Regelbrugge et al (2003) derived a simple, physicsbased model to describe basic operating characteristics of piezohydraulic actuators. The bulk modulus of the hydraulic fluid along with mass flow rates through different control volumes were used to calculate the pressures in the corresponding sections of the actuator.…”

Section: Dynamic Actuator Models In Time Domainmentioning

confidence: 99%

Compact hybrid electrohydraulic actuators using smart materials: A review

Chaudhuri

Wereley

2011

Journal of Intelligent Material Systems and Structures

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The development of compact hybrid electrohydraulic actuators driven by various smart materials has been widely reported in the literature in recent years. Such solid-state-induced strain actuators have applications in a variety of aerospace and automotive and mechanical engineering fields. These devices are capable of producing high stroke (or displacement) and high force (or pressures) in a compact form factor by utilizing the large bandwidth and energy density of currently available smart materials. The basic operation of these hybrid actuators involves high-frequency bidirectional operation of an active material that is converted to unidirectional motion of a hydraulic fluid by a set of valves. Over the last decade, several prototype hybrid actuators have been designed using piezoelectric (PZT-5H), magnetostrictive (Terfenol-D), and electrostrictive (PMN-PT) materials as the driving elements, with actuation frequencies ranging from 10 Hz to 1 kHz. Power outputs and volumetric flow rates have reached up to 20 W and 40 cm3/s, respectively. Different mathematical models have been developed to evaluate the performance of these hybrid actuators. While early efforts focused on a simple, quasi-static approach to simulate pump operation, more complex dynamic models have been recently developed to capture the complex interaction between the smart material and the transmission fluid at high operating frequencies. The objective of this survey is to review the state-of-the-art in compact hybrid electrohydraulic actuation systems and to summarize design and modeling efforts.

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“…10 All of these approaches treat the flow in an essentially one dimensional manner in which pressure losses through orifices are related to the volume flow rate using a loss coefficient. These coefficients are usually derived from standard fluid handbooks or from steady, axisymmetric CFD analyses 11 While most of these models work reasonably well at low frequencies (below a few hundred Hz), they do not predict behavior at the higher frequencies ( 1kHz) where the hybrid actuators are intended to operate.…”

Section: Introductionmentioning

confidence: 99%

Unsteady fluid flow in smart material actuated fluid pumps

John

Cadou

2005

SPIE Proceedings

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Smart materials' ability to deliver large block forces in a small package while operating at high frequencies makes them extremely attractive for converting electrical to mechanical power. This has led to the development of hybrid actuators consisting of co-located smart material actuated pumps and hydraulic cylinders that are connected by a set of fast-acting valves. The overall success of the hybrid concept hinges on the effectiveness of the coupling between the smart material and the fluid. This, in turn, is strongly dependent on the resistance to fluid flow in the device. This paper presents results from three-dimensional unsteady simulations of fluid flow in the pumping chamber of a prototype hybrid actuator powered by a piezo-electric stack. The results show that the forces associated with moving the fluid into and out of the pumping chamber already exceed 10% of the piezo stack blocked force at relatively low frequencies 120 Hz and approach 40% of the blocked force at 800 Hz. This reduces the amplitude of the piston motion in such a way that the volume flow rate remains approximately constant above operating frequencies of 500 Hz while the efficiency of the pump decreases rapidly.

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Design Model for Piezohydraulic Actuators

Cited by 13 publications

References 5 publications

Design and testing of piezoelectric-hydraulic actuators

Design and testing of piezoelectric-hydraulic actuators

Compact hybrid electrohydraulic actuators using smart materials: A review

Unsteady fluid flow in smart material actuated fluid pumps

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