Mechanical amplifier

About: Mechanical amplifier is a research topic. Over the lifetime, 112 publications have been published within this topic receiving 1777 citations.

A micro strain gauge with mechanical amplifier

Abstract: A passive micro strain gauge with a mechanical amplifier has been designed, analyzed, and tested. The mechanical amplifier provides a high gain such that residual strain in thin films can be directly measured under an optical microscope. This strain gauge can be in situ fabricated with active micro sensors or actuators for monitoring residual strain effects, and both tensile and compressive residual strains can be measured via the strain gauge. It is shown that a very fine resolution of 0.001% strain readouts can be achieved for a micro strain gauge with a 500 /spl mu/m-long indicator beam. Beam theories have been used to analyze the strain gauge with a mechanical amplifier, and the results were verified by a finite-element analysis. Experimental measurements of both polysilicon and silicon-riched silicon-nitride thin films fabricated by surface micromachining processes are presented.

Tuning a resonant energy harvester using a generalized electrical load

Abstract: A fundamental drawback of vibration-based energy harvesters is that they typically feature a resonant mass/spring mechanical system to amplify the small source vibrations; the limited bandwidth of the mechanical amplifier restricts the effectiveness of the energy harvester considerably. By extending the range of input frequencies over which a vibration energy harvester can generate useful power, e.g. through adaptive tuning, it is not only possible to open up a wider range of applications, such as those where the source frequency changes over time, but also possible to relax the requirements for precision manufacture or the need for mechanical adjustment in situ. In this paper, a vibration-based energy harvester connected to a generalized electrical load (containing both real and reactive impedance) is presented. It is demonstrated that the reactive component of the electrical load can be used to tune the harvester system to significantly increase the output power away from the resonant peak of the device. An analytical model of the system is developed, which includes non-ideal components arising from the physical implementation, and the results are confirmed by experiment. The − 3 dB (half-power) bandwidth of the prototype energy harvester is shown to be over three times greater when presented with an optimized load impedance compared to that for the same harvester presented with an optimized resistive only load.

Topology optimization of compliant mechanical amplifiers for piezoelectric actuators

Abstract: A method for the design of displacement amplifying compliant mechanisms for piezoelectric actuators is developed using a topology optimization approach. The overall stroke amplification or geometric advantage of the mechanism, and the overall mechanical efficiency of the mechanism are considered as objective functions. The maximization of these objective functions is accomplished using two different solution methods, Sequential Linear Programming and an Optimality Criteria method. The focus of this paper is on the underlying topology optimization problem formulations and the solution methods. Design examples are presented which illustrate the method, with comparisons of the computation time and mechanism performance for the two formulations and solution methods. A procedure has also been developed to automatically convert the topology optimization results to a solid CAD model. A prototype design has been fabricated to serve as proof of concept.