The 58th Shock and Vibration Symposium, volume 1

The proceedings of the 58th Shock and Vibration Symposium, held in Huntsville, Alabama, October 13 to 15, 1987 are given. Mechanical shock, dynamic analysis, space shuttle main engine vibration, isolation and damping, and analytical methods are discussed

Fourth Aircraft Interior Noise Workshop

The fourth in a series of NASA/SAE Interior Noise Workshops was held on May 19 and 20, 1992. The theme of the workshop was new technology and applications for aircraft noise with emphasis on source noise prediction; cabin noise prediction; cabin noise control, including active and passive methods; and cabin interior noise procedures. This report is a compilation of the presentations made at the meeting which addressed the above issues

Research and Technology

Langley Research Center is engaged in the basic an applied research necessary for the advancement of aeronautics and space flight, generating advanced concepts for the accomplishment of related national goals, and provding research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Highlights of major accomplishments and applications are presented

FLEXIBLE LOW-COST HW/SW ARCHITECTURES FOR TEST, CALIBRATION AND CONDITIONING OF MEMS SENSOR SYSTEMS

During the last years smart sensors based on Micro-Electro-Mechanical systems (MEMS) are widely spreading over various fields as automotive, biomedical, optical and consumer, and nowadays they represent the outstanding state of the art. The reasons of their diffusion is related to the capability to measure physical and chemical information using miniaturized components. The developing of this kind of architectures, due to the heterogeneities of their components, requires a very complex design flow, due to the utilization of both mechanical parts typical of the MEMS sensor and electronic components for the interfacing and the conditioning. In these kind of systems testing activities gain a considerable importance, and they concern various phases of the life-cycle of a MEMS based system. Indeed, since the design phase of the sensor, the validation of the design by the extraction of characteristic parameters is important, because they are necessary to design the sensor interface circuit. Moreover, this kind of architecture requires techniques for the calibration and the evaluation of the whole system in addition to the traditional methods for the testing of the control circuitry. The first part of this research work addresses the testing optimization by the developing of different hardware/software architecture for the different testing stages of the developing flow of a MEMS based system. A flexible and low-cost platform for the characterization and the prototyping of MEMS sensors has been developed in order to provide an environment that allows also to support the design of the sensor interface. To reduce the reengineering time requested during the verification testing a universal client-server architecture has been designed to provide a unique framework to test different kind of devices, using different development environment and programming languages. Because the use of ATE during the engineering phase of the calibration algorithm is expensive in terms of ATE’s occupation time, since it requires the interruption of the production process, a flexible and easily adaptable low-cost hardware/software architecture for the calibration and the evaluation of the performance has been developed in order to allow the developing of the calibration algorithm in a user-friendly environment that permits also to realize a small and medium volume production. The second part of the research work deals with a topic that is becoming ever more important in the field of applications for MEMS sensors, and concerns the capability to combine information extracted from different typologies of sensors (typically accelerometers, gyroscopes and magnetometers) to obtain more complex information. In this context two different algorithm for the sensor fusion has been analyzed and developed: the first one is a fully software algorithm that has been used as a means to estimate how much the errors in MEMS sensor data affect the estimation of the parameter computed using a sensor fusion algorithm; the second one, instead, is a sensor fusion algorithm based on a simplified Kalman filter. Starting from this algorithm, a bit-true model in Mathworks Simulink(TM) has been created as a system study for the implementation of the algorithm on chip

Enhancements of MEMS design flow for Automotive and Optoelectronic applications

In the latest years we have been witnesses of a very rapidly and amazing grown of MicroElectroMechanical systems (MEMS) which nowadays represent the outstanding state-of-the art in a wide variety of applications from automotive to commercial, biomedical and optical (MicroOptoElectroMechanicalSystems). The increasing success of MEMS is found in their high miniaturization capability, thus allowing an easy integration with electronic circuits, their low manufacturing costs (that comes directly from low unit pricing and indirectly from cutting service and maintaining costs) and low power consumption. With the always growing interest around MEMS devices the necessity arises for MEMS designers to define a MEMS design flow. Indeed it is widely accepted that in any complex engineering design process, a well defined and documented design flow or procedure is vital. The top-level goal of a MEMS/MOEMS design flow is to enable complex engineering design in the shortest time and with the lowest number of fabrication iterations, preferably only one. These two characteristics are the measures of a good flow, because they translate directly to the industry-desirable reductions of the metrics “time to market” and “costs”. Like most engineering flows, the MEMS design flow begins with the product definition that generally involves a feasibility study and the elaboration of the device specifications. Once the MEMS specifications are set, a Finite Element Method (FEM) model is developed in order to study its physical behaviour and to extract the characteristic device parameters. These latter are used to develop a high level MEMS model which is necessary to the design of the sensor read out electronics. Once the MEMS geometry is completely defined and matches the device specifications, the device layout must be generated, and finally the MEMS sensor is fabricated. In order to have a MEMS sensor working according to specifications at first production run is essential that the MEMS design flow is as close as possible to the optimum design flow. The key factors in the MEMS design flow are the development of a sensor model as close as possible to the real device and the layout realization. This research work addresses these two aspects by developing optimized custom tools (a tool for layout check (LVS) and a tool for parasitic capacitances extraction) and new methodologies (a methodology for post layout simulations) which support the designer during the crucial steps of the design process as well as by presenting the models of two cases studies belonging to leading MEMS applications (a micromirror for laser projection system and a control loop for the shock immunity enhancement in gyroscopes for automotive applications)

Advanced Knowledge Application in Practice

The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research