Effect of Continuous Working Fluid Flow Direction on Power Generation from Piezoelectric Sensors

This paper presents an experimental study to support the concept of generating energy by a continuous flow of water using piezoelectric sensors. This study is aimed to determine the effect of external force direction of continuous water flow, i.e., vertical and horizontal, on the output of the piezoelectric sensors. The piezoelectric type of ABT-441-RC is used and arranged in parallel. IC MAX471 as an amplifier and Arduino Uno R3 to read the flow rate, voltage, and current were employed. Flow rates with variations of 0.00011 up to 0.00030 m3/s are set to study the voltage and current of the output. The numbers of piezoelectric sensors used are 4, 6, 8, and 20. As a result, it is found that the pressure in the vertical direction differs up to 68% from the pressure in the horizontal one. The voltage and current in the vertical direction, compared to that of the horizontal direction, differ as much as 85% at a low flow rate and decrease down to 63% at a high flow rate for voltage and 86% to 34% at a low to high flow rate for current. In conclusion, the current generation by the present arrangement is within the micro-ampere range, and the voltage is in a volt range, respectively

Wireless sensor networks for active vibration control in automobile structures

International audienceWireless Sensor Network (WSN) are nowadays widely used in monitoring and tracking applications. This paper presents the feasibility of using Wireless Sensor Networks in active vibration control strategy. The active control method used is an active-structural acoustic control using piezoelectric sensors distributed on the car structure. This system aims at being merged in wireless sensor network whose head node collects data and process control law so as to command piezoelectric actuators wisely placed on the structure. We will study the feasibility of implementing WSN in active vibration control and introduce a complete design methodology to optimize hardware/software and control law synergy in mechatronic systems. A design space exploration will be conducted so as to identify the best Wireless Sensor Network platform and the resulting impact on control

Microelectromechanical Systems and Devices

The advances of microelectromechanical systems (MEMS) and devices have been instrumental in the demonstration of new devices and applications, and even in the creation of new fields of research and development: bioMEMS, actuators, microfluidic devices, RF and optical MEMS. Experience indicates a need for MEMS book covering these materials as well as the most important process steps in bulk micro-machining and modeling. We are very pleased to present this book that contains 18 chapters, written by the experts in the field of MEMS. These chapters are groups into four broad sections of BioMEMS Devices, MEMS characterization and micromachining, RF and Optical MEMS, and MEMS based Actuators. The book starts with the emerging field of bioMEMS, including MEMS coil for retinal prostheses, DNA extraction by micro/bio-fluidics devices and acoustic biosensors. MEMS characterization, micromachining, macromodels, RF and Optical MEMS switches are discussed in next sections. The book concludes with the emphasis on MEMS based actuators

Engineering Education and Research Using MATLAB

MATLAB is a software package used primarily in the field of engineering for signal processing, numerical data analysis, modeling, programming, simulation, and computer graphic visualization. In the last few years, it has become widely accepted as an efficient tool, and, therefore, its use has significantly increased in scientific communities and academic institutions. This book consists of 20 chapters presenting research works using MATLAB tools. Chapters include techniques for programming and developing Graphical User Interfaces (GUIs), dynamic systems, electric machines, signal and image processing, power electronics, mixed signal circuits, genetic programming, digital watermarking, control systems, time-series regression modeling, and artificial neural networks

Wireless Tagging and Actuation with Shaped Magnetoelastic Transducers.

The promise and the challenges of patterned, micro-scale magnetoelastic transducers and their integration with silicon is the focus of this thesis. As demonstrations, wireless magnetoelastic chip-scale resonant rotary motors and miniaturized magnetoelastic tags are investigated. The motors consist of a magnetoelastically-actuated stator, a silicon rotor, a “hub” structure, and DC and AC coils. Two generations are described. The first-generation motor uses a stator with a bilayer of silicon (ø8 mm x 65 µm thick) and magnetoelastic foil (Metglas™ 2826MB bulk foil, ø8 mm x 25 µm thick). The motor provides bi-directional rotation capability, and typical resonant frequencies of the clockwise and counterclockwise modes are 6.1 kHz and 7.9 kHz, respectively. The counterclockwise mode provides a rotation rate of ≈100 rpm, start torque of 30 nN∙m, a step size of 74 milli-degree and a capability for driving a 100 mg payload while a 8 Oe DC and a 6 Oe-amplitude AC magnetic field are applied. The second-generation of motors includes bilayer standing wave and traveling wave designs (ø5 mm stators) with integrated capacitive sensors for real-time position measurement and speed estimation. Clockwise and counterclockwise mode shapes with resonant frequencies of 12 kHz and 22.4 kHz, respectively, are measured for the standing wave motor. Two mode shapes (with π/2 spatial phase difference) at resonant frequencies of 30.2 kHz and 31.7 kHz are measured for the traveling wave motor. The wireless actuation capability and the hybrid integration of the bulk magnetoelastic material with silicon show promise for use in many microsystems. A lithographically patterned, frame-suspended hexagonal magnetoelastic tag design (ø1.3 mm x 27 µm thick) is also investigated. These tags provide ≈75x signal amplitude improvement compared to a non-suspended disc tag, while occupying ≈100x smaller area than typical commercial ribbon tags. Signal strength can also be boosted by taking advantage of tag signal superposition. Linear signal superposition of the response has been experimentally measured for clustered sets of frame-suspended tags that include as many as 500 units. Miniaturized tags with sufficient signal strength may enable new applications, such as distributing the tags into a network of cracks and subsequently mapping the distribution.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/108961/1/juntang_1.pd

Prosthetic Control and Sensory Feedback for Upper Limb Amputees

Hand amputation could dramatically degrade the life quality of amputees. Many amputees use prostheses to restore part of the hand functions. Myoelectric prosthesis provides the most dexterous control. However, they are facing high rejection rate. One of the reasons is the lack of sensory feedback. There is a need for providing sensory feedback for myoelectric prosthesis users. It can improve object manipulation abilities, enhance the perceptual embodiment of myoelectric prostheses and help reduce phantom limb pain. This PhD work focuses on building bi-directional prostheses for upper limb amputees. In the introduction chapter, first, an overview of upper limb amputee demographics and upper limb prosthesis is given. Then the human somatosensory system is briefly introduced. The next part reviews invasive and non-invasive sensory feedback methods reported in the literature. The rest of the chapter describes the motivation of the project and the thesis organization. The first step to build a bi-directional prostheses is to investigate natural and robust multifunctional prosthetic control. Most of the commerical prostheses apply non-pattern recognition based myoelectric control methods, which offers only limited functionalities. In this thesis work, pattern recognition based prosthetic control employing three commonly used and representative machine learning algorithms is investigated. Three datasets involving different levels of upper arm movements are used for testing the algorithm effectiveness. The influence of time-domain features, window and increment sizes, algorithms, and post-processing techniques are analyzed and discussed. The next three chapters address different aspects of providing sensory feedback. The first focus of sensory feedback process is the automatic phantom map detection. Many amputees have referred sensation from their missing hand on their residual limbs (phantom maps). This skin area can serve as a target for providing amputees with non-invasive tactile sensory feedback. One of the challenges of providing sensory feedback on the phantom map is to define the accurate boundary of each phantom digit because the phantom map distribution varies from person to person. Automatic phantom map detection methods based on four decomposition support vector machine algorithms and three sampling methods are proposed. The accuracy and training/ classification time of each algorithm using a dense stimulation array and two coarse stimulation arrays are presented and compared. The next focus of the thesis is to develop non-invasive tactile display. The design and psychophysical testing results of three types of non-invasive tactile feedback arrays are presented: two with vibrotactile modality and one with multi modality. For vibrotactile, two types of miniaturized vibrators: eccentric rotating masses (ERMs) and linear resonant actuators (LRAs) were first tested on healthy subjects and their effectiveness was compared. Then the ERMs are integrated into a vibrotactile glove to assess the feasibility of providing sensory feedback for unilateral upper limb amputees on the contralateral hand. For multimodal stimulation, miniature multimodal actuators integrating servomotors and vibrators were designed. The actuator can be used to deliver both high-frequency vibration and low-frequency pressures simultaneously. By utilizing two modalities at the same time, the actuator stimulates different types of mechanoreceptors and thus h

Technology 2002: the Third National Technology Transfer Conference and Exposition, Volume 1

The proceedings from the conference are presented. The topics covered include the following: computer technology, advanced manufacturing, materials science, biotechnology, and electronics

Development of a monolithic near-field optomechanical system

In the same year as Einstein's annus mirabilis, English engineer and physicist John Flemming patented the first rectifying diode, which he called the "Flemming valve". Einstein's work on the photoelectric effect would change our understanding of the nature of light - a pivotal moment in the development of quantum theory. Flemming's diode would transform our world as well, often pointed to as the beginning of modern electronics. These ideas, born in the same moment, have remained entwined. Quantum theory has been fundamental to transistor development, and that, in turn, led to the computer revolution and accompanying development of silicon manufacturing. The theoretical and technological gifts these ideas have accumulated over the past hundred years are now laid to bare in the field of cavity optomechanics. The silicon technology that owes its very existence to quantum theory is now leveraged to test the limitations of theory and perhaps to exploit quantum resources for a new class of sensors. Micro-, and even nano-scale, optical cavities are coupled to commensurately miniaturized mechanical oscillators, where strong radiation pressure mediated interactions between their corresponding modes can be realized. The fluctuating position of a mechanical element is imprinted on the phase of light circulating within the cavity, while the varying amplitude of the light alters its momentum. Quantum fluctuations are imprinted on the mechanical element by light within the cavity, establishing correlations between its phase and amplitude. Utilizing the optomechanical system developed in this thesis work we are able to observe the signature of these induced correlations, even in the presence of thermal noise at room-temperature. Moreover, we demonstrate the principle by which correlations can be used to cancel measurement back-action, producing a quantum-enhanced sensitivity to external forces. The system in question is also demonstrated to achieve an imprecision more than three orders of magnitude below that at the standard quantum, at room-temperature, which is unprecedented. A strong radiation pressure interaction between a micron-scale mechanical element and an optical cavity has been achieved by taking advantage of many of the powerful tools developed in the context of building modern computers. Using transistor technology in this new context we engineer an optomechanical system that exhibits an exceptionally large contribution of back-action relative to thermal noise. In addition to observing this back-action signature at ambient temperatures, the large interaction strength is applied to the task of laser cooling with a measurement-based feedback scheme. In this framework, we demonstrate the ability to reduce the thermal occupation of a cryogenically cooled mechanical mode by an additional three orders of magnitude, to a mean occupancy of just 5.3 phonons

A 2-D VHDL-AMS Model for Disk-Shape Piezoelectric Transducers

International audiencePiezoelectric materials are widely used for many applications such as sensors, actuators. Today, their integration in microelectronics processes like CMOS requires the development of advanced realistic behavioral models. Until now, these models were limited to only one ceramic's operation mode, i.e., thickness or planar. Moreover, the robustness of piezo-electronic system cannot be adequately addressed as long as models are not improved, in particular by taking into account further real phenomena. This article proposes to merge, in a new behavioral model, the two operation modes. It is demonstrated that the electrical behavior of the proposed model is in very good agreement with the real ceramic behavior