Bimorph

About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.

Dynamic modeling and input shaping of thermal bimorph MEMS actuators

Abstract: Thermal bimorphs are a popular actuation technology in MEMS (micro-electro-mechanical systems). Their operating principle is based on differential thermal expansion induced by Joule heating. Thermal bimorphs, and other thermal flexure actuators have been used in many applications, from micro-grippers, to micro-optical mirrors. In most cases open-loop control is used to difficulties in fabricating positioning sensors together with actuator. In this paper we present several methods for extracting reduced-order thermal flexure actuator models based on experimental data, physical principles, and FEA simulation. We then use the models to generate optimal driving signals using input shaping techniques. Both simulation and experimental results are included to illustrate the efficacy of our approach. This framework can also be applied to other types of MEMS actuators, including electrostatic comb drives.

Design, Fabrication, And Testing Of A C-shape Actuator

Abstract: SUMMARY This paper describes the design, fabrication, and testing of a microactuator, whose bimorph beams curl up to form a C-shape and reach hundreds of microns from the substrate. The multi-layer C-shape beams were designed by FEM nonlinear analysis and fabricated on a silicon wafer by surface micromachining involving polyimide and metal thin films. The large curvature (i.e., small radius of curvature) is achieved by utilizing the large residual stress difference between thin films. The device is normally curled up, and it opens up by either electrostatic or thermal actuation. The device was operated successfully in liquid as well as in air to their full range between complete curl up and flat positions, demonstrating tip displacements of over two hundred microns.

Bimorph Piezoelectric Micromachined Ultrasonic Transducers

Abstract: This paper presents the concept, basic theory, fabrication, and testing results of dual-electrode bimorph piezoelectric micromachined ultrasonic transducers (pMUTs) for both air- and liquid-coupled applications. Both the theoretical analyses and experimental verifications under the proposed differential drive scheme display high drive sensitivity and an electromechanical coupling energy efficiency that is as high as $4\times $ of the state-of-the-art pMUT with a similar geometry and frequency. The prototype transducers are fabricated in a CMOS-compatible process with the radii of 100–230 $\mu \text{m}$ using aluminum nitride as the piezoelectric layers with the thicknesses varying from 715 to 950 nm and molybdenum (Mo) as the electrodes with a thickness of 130 nm. The tested operation frequencies of the prototype transducers are 200–970 kHz in air for possible ranging and motion detection applications, and from 250 kHz to 1 MHz in water for medical ultrasound applications such as fracture healing, tumor ablation, and transcranial sonothrombolysis. A $12\times 12$ array structure is measured to have the highest intensity per voltage squared, per number of pMUTs squared, and per piezoelectric constant squared ( $I_{n}= I/(VNd_{31})^{2})$ among all reported pMUT arrays. The generated acoustic intensity is in the range of 30–70 mW/cm2 up to 2.5 mm from the transducer surface in mineral oil with a driving voltage of 5 $\text{V}_{{\mathrm{ac}}}$ , which is suitable for battery-powered therapeutic ultrasound devices. [2015-0305]

Design, fabrication and initial results of a 2g autonomous glider

Abstract: Utilizing the core technologies of emerging microrobotic structures, the rapid design and prototyping of a passive micro air vehicle with the final goal of locating an audio source while avoiding hazardous obstacles is presented. The airfoil and control surfaces are optimized empirically to maximize lift and maneuverability while minimizing drag. Bimorph piezoelectric bending cantilevers actuate the control surfaces. Since such actuators require high voltages, an efficient boost circuit is presented along with appropriate high voltage electronics. To locate audio sources, a pair of acoustic sensors is designed and prototyped using a phase detection algorithm while a custom optic flow sensor is developed to avoid obstacles and give estimates of object distances and velocities. Finally, each subsystem is demonstrated and the complete glider is integrated to demonstrate initial open loop control performance.

A novel tiny ultrasonic linear motor using the radial mode of a bimorph

Abstract: The new-typed tiny ultrasonic motor has been introduced to have compact and simple structure. The linear motion of a new-type linear motor is operated by a principle of inertia displacement. The motor can be realized by the central movement of transducing part, which is the maximum displacement of the up-and-down movement. The transducing parts, using different diameters, 3.0 and 5.0 mm and thickness of 0.1 and 0.2 mm metal disks, were fabricated and the dynamic characteristics of the motors were measured. The motor with piezoelectric ceramic of O3 needs higher operating voltage than the motor with the piezoelectric ceramic of O5.