This paper analyses scale effects for actuator types which are strong candidates for micro-actuation: shape memory alloys (SMAS), electrostatic, electromagnetic and piezoelectric actuators. SMA actuators are studied in detail and compared to the other actuator types on a basis of force, response time, and power densi~. Much of the analysis is based on thermal aspects and scaling effects on both...

This paper demonstrates that a hydraulically acting Helmholtz resonator can exist in a piezoelectric–hydraulic pump (PHP) based hybrid actuator, which in turn affects the volumetric efficiency of the PHP. The simulation and experimental results illustrate the effect of Helmholtz resonance on the flow rate performance of the PHP. The study also shows how to shift the Helmholtz resonant frequency...

This paper studies a new nested switching control (NSC) scheme for piezoelectric (PZT) actuators to achieve fast nanopositioning. Conventional PZT controllers typically neglect the actuator saturation nonlinearity for design simplicity but at the cost of reduced performance. By optimizing a quadratic performance cost function that explicitly involves the actuator saturation, the NSC can not onl...

We consider an initial and boundary value problem modelling the vibrations of a Bernoulli-Euler beam with an attached piezoelectric actuator. We show that the Sobolev regularity of the solution is by 1 2 + higher than that one obtains by simply using the Sobolev regularity of the control term. The main results concern the dependence of the space of exactly controllable initial data on the locat...

The paper presents a new parallel micromanipulator that is composed of three piezohydraulic actuation systems. The basic elements of the actuation system are a piezoelectric actuator, a bellows and hydraulic oil. The use of the flexible bellows results in a new type of parallel structure, where the joints are integrated into actuator links. The joint-free tripod-like micromanipulator is control...

Currently, most of the integrated sorting modules in the microfabricated DEP-based and fluorescent-activated cell sorters (μFACS) still suffer from low-throughput operation and require complex fabrication process (e.g. embedded electrodes) and high power consumption (e.g. electrokinetically-driven sorters). In this paper, we demonstrate an easy-to-fabricate, low-powered and high-speed sorting m...

In this paper, a bio-inspired bending actuator was designed and fabricated using piezoelectric patches and cantilever-shaped beam for controlling nose shape. The aim of this study is to investigate the use of the bending actuator. PZT and single crystal PMN-PT actuators were used to generate translational strain and shear stress. The piezoelectric patches were attached on the clamped cantilever...

Abstract: In many industrial applications like semiconductor production and optical inspection systems, the availability of positioning systems capable to follow trajectory paths in the range of several centimetres, featuring at the same time a nanometre-range precision, is demanding. Pure piezoelectric stages and standard positioning systems with motor and spindle are not able to meet such req...

A Comb Drive Actuator is a basic actuation device of MEMS. MEMS applications often require large force, large displacement, low-power and energy-efficient actuators. Low power consumption is highly desirable not only for economic reasons, but also for heat generation considerations. In this paper, different types of structural design of Comb Drive Actuator that is Fixed-Fixed Flexure Beam, Crab...

INTRODUCTION Magnetic resonance elastography (MRE) is a phase-contrast technique that can noninvasively visualize shear waves patterns within tissue [1]. Accurate values of tissue stiffness are calculated by the equations of motion from the shear wave pattern of a single frequency [2]. In order to generate shear waves within tissue, various external drivers have been proposed [3]. To acquire an...