Bimorph

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

A method of broadening the bandwidth by tuning the proof mass in a piezoelectric energy harvesting cantilever

Abstract: We propose and demonstrate a new method for broadening the bandwidth of a piezoelectric energy harvesting cantilever by tuning a proof mass. Our approach is to make the bandwidth broad by decreasing the difference between two consecutive flexural resonance frequencies of the cantilever. The prototype broadband energy harvesting device consists of a cantilever with double piezoelectric patch and a tuned proof mass, which is composed of two different materials: aluminium and brass. We tuned resonance frequencies of the device based on the optimal design framework. In order to prove the effectiveness of the proposed device, prototypes of two cantilevers, one with a tuned proof mass and the other with a conventional proof mass, were manufactured and the same bimorph cantilever were used in prototypes. Performances of the manufactured prototypes were evaluated and compared. It is observed that the proposed device shows a 426.6 % increase in bandwidth at the same output level and 508.5 % increase in power compared to the conventional device.

A comparison of power harvesting techniques and related energy storage issues

Abstract: Power harvesting, energy harvesting, power scavenging, and energy scavenging are four terms commonly used to describe the process of extracting useful electrical energy from other ambient energy sources using special materials called transducers that have the ability to convert one form of energy into another. While the words power and energy have vastly different definitions, the terms “power harvesting” and “energy harvesting” are used interchangeably throughout much of the literature to describe the same process of extracting electrical energy from ambient sources. Even though most of the energy coupling materials currently available have been around for decades, their use for the specific purpose of power harvesting has not been thoroughly examined until recently, when the power requirements of many electronic devices has reduced drastically. The overall objective of this research is to typify the power source characteristics of various transducer devices in order to find some basic way to compare the relative energy densities of each type of device and, where possible, the comparative energy densities within subcategories of harvesting techniques. Included in this research is also a comparison of power storage techniques, which is often neglected in other literature sources. An initial analysis of power storage devices explores the background of secondary (rechargeable) batteries and supercapacitors, the advantages and disadvantages of each, as well as the promising characteristics of recent supercapacitor technology developments. Also explored is research into the effectiveness of piezoelectric energy harvesting for the purpose of battery charging, with particular focus on the current output of piezoelectric harvesters. The first objective involved presenting and verifying a model for a cantilever piezoelectric bimorph. Next, an investigation into new active fiber composite materials and macro fiber composite devices utilizing the d31 coefficient is performed in comparison to a monolithic piezoelectric bimorph. The information gathered here was used to design a two bimorph device termed the mobile energy harvester (MEH). Worn by a human being at the waste level, the MEH harvests energy from each footfall during walking or running. The next objective involved characterizing small temperature gradient (less than 200 C) thermoelectric generators (TEGs). Four TEGs were linked in series and joined with a specially made aluminum base and fin heat sink. This device was then mounted to the exhaust system of an automobile and proved capable of recharging both an 80 and a 300 milliamp-hour battery. A switching circuit concept to step up the output voltage is also presented. However, the circuit proves somewhat difficult to implement, so an alternative DC/DC device is proposed as a possible solution. With the advent of highly efficient, low voltage DC to DC converters, it is shown that their high current, low voltage output can be converted to a higher voltage source that is suitable for many electronic and recharging applications. As extensive literature exists on the capabilities of photovoltaic and electromagnetic energy harvesting, no original experimentation is presented. Instead, only a brief overview of the pertinent technological advances is provided in this document for the purpose of comparison to piezoelectric and thermoelectric energy harvesting. The main research focus, as described above, is dedicated to designing and performing original experiments to characterize cutting edge piezoelectric and thermoelectric transducer materials. To conclude and unify the document, the final section compares the power harvesting techniques with one another and introduces methods of combining them to produce a hybrid, multiple energy domain harvesting device. A piezoelectric-electromagnetic harvesting combination device is presented and scrutinized, revealing that such a device could improve the amount of energy extracted from a single harvesting unit. The research presented here not only expands on the present understanding of these materials, but also proposes a new method of creating a hybrid power harvesting device utilizing two of the energy coupling domains, electromechanical and piezoelectric. The goal is to maximize the harvested energy by tapping into as many ambient sources as are available and practical.

Microactuator for dynamic controlling head-media interaction and fly-height

Abstract: A microactuating suspension assembly used for a disc drive is disclosed. The microactuating suspension assembly has a suspension load beam and a microactuator placed on the suspension load beam for bending the suspension load beam at the front end thereof during a sustained period of data read/write time and thus achieving a desired average fly-height which is different from an unaltered average fly-height which would have been achieved without the microactuator. In particular, the microactuating suspension assembly can be used to achieve a very low fly-height. Additionally, very large bandwidth and very short seeking time is made possible when a bimorph piezoelectric microactuator is used.

A piezoelectric bimorph micro-gripper with micro-force sensing

Abstract: A new piezoelectric bimorph micro-gripper with micro-force sensing is presented in the paper The micro-gripper is based on the dual cantilevers structure and is driven by two piezoelectric bimorphs Sticking two strain gauges on both sides of the base of the piezoelectric bimorph to sense free end transmutation of the bimorph, we can get displacement-voltage relationship and force-strain relationship respectively As a result the gripper has the ability to detect micro-force when it is gripping micro-parts The experiment results show that the gripper works reliably and safely It is satisfied with the tasks of micro assembly