1,721,030 research outputs found
MEMS for automotive and aerospace applications
No full textMEMS for automotive and aerospace applications reviews the use of Micro-Electro-Mechanical-Systems (MEMS) in developing solutions to the unique challenges presented by the automotive and aerospace industries.Part one explores MEMS for a variety of automotive applications. The role of MEMS in passenger safety and comfort, sensors for automotive vehicle stability control applications and automotive tire pressure monitoring systems are considered, along with pressure and flow sensors for engine management, and RF MEMS for automotive radar sensors. Part two then goes on to explore MEMS fo
Polymer thick-films on silicon: A route to hybrid microsystems
No full textThe integration of polymer thick-film transducers and silicon offers a low-cost technology for the fabrication of hybrid microsystems. This paper presents a study on the feasibility and processing parameters of this integration. Selected transducer films were printed on silicon wafers covered with aluminum or various passivation layers and also on alumina for comparison. The quality of film adhesion was investigated using standard tape pull and scratch tests. Scanning electron microscopy and energy dispersive x-ray spectra analysis were used to investigate the interface between the films and the substrates. It was found that the films did not contaminate the wafers. We also characterized the film resolution by researching the wetting behavior of the pastes and the quality of printed patterns. The influence of the substrate's thermal coefficient of expansion on the resistance of a carbon polymer film was also analyzed. The experiments showed that the same design rules can be applied on both alumina and silicon substrates. Furthermore, dry and wet methods of etching and cleaning wafers from the thick-films were assessed. An insight into the potential and limitations of the technology is developed by discussing the issues of bonding mechanism, silicon contamination and influence of substrate on the resolution, electrical properties and infrared curing of the films. A design methodology for hybrid microsystems is proposed along with a suggestion for potential applications
Application of Analog Adaptive Filters for Dynamic Sensor Compensation
No full textThis paper investigates the application of analog adaptive techniques to the area of dynamic sensor compensation, of which there is little reported work in the literature. The case is illustrated by showing how the response of a load cell can be improved to speed up the process of measurement. The load cell is a sensor with an oscillatory output in which the measurand contributes to the response parameters. Thus, a compensation filter needs to track variation in measurand whereas a simple, fixed filter is only valid at one specific load value. To facilitate this investigation, computer models for the load cell and the adaptive compensation filter have been developed. To allow a practical implementation of the adaptive techniques, a novel piecewise linearization technique is proposed in order to vary a floating voltage-controlled resistor in a linear manner over a wide range. Simulation and practical results are presented, thus demonstrating the effectiveness of the proposed techniques
Improving the piezoelectric properties of thick-film PZT: the influence of paste composition, powder milling process and electrode material
No full textThis paper details improvements of the d33 coefficient for thick-film Lead–Zirconate–Titanate (PZT) layers. In particular, the effect that the powder milling process has on particle size, shape and distribution has been investigated. Ball milled, jet milled and attritor milled powders were obtained from Morgan Electro-Ceramics Ltd. These powders were mixed with various ratios of lead borosilicate glass in the range of 5–20% by weight and an appropriate quantity of Electro-Science Laboratories (ESL) 400 solvent to formulate a screen printable thixotropic paste. The use of a polymer top electrode to reduce the number of firing cycles the PZT layer is subjected to was also investigated. The results show that the highest values of d33 were obtained from the ball milled powder with 10% glass content, but the most consistent results were obtained from the attritor milled samples. The samples printed with a polymer top electrode have shown an average increase of around 15% in the value of d33
An Instrumented Crutch for Monitoring Patients' Weight Distribution during Orthopaedic Rehabilitation
No full textThis paper discusses an instrumented forearm crutch that has been developed to monitor a patient’s weight bearing over the full period of their recovery, and that can potentially be used in a home environment. The crutch measures the applied weight, crutch tilt, and hand position on the grip. Data are transmitted wirelessly to a remote computer, where they are processed and visualized in LabVIEW. The results obtained from a successful pilot study highlight both the need for such an instrumented crutch and its ability to measure the weight being applied through a patient’s lower limb
Adaptive Sensor Response Correction Using Analog Filter Compatible with Digital Technology
No full textAn analog adaptive filter for response correction of a load cell sensor is presented. The filter employs only transistors and therefore it can be integrated using digital CMOS technology, which is suitable for System-on-Chip applications. To achieve adaptive compensation over a wide range of measurand, a novel CMOS multiplier was developed. The analog adaptive filter has been simulated using 0.35µm 3.3V BSim3v3 CMOS foundry models and found to perform effective compensation
Effects of the binder material on the mechanical properties of thick-film magnetostrictive materials
No full textThis paper presents research carried out at the University of Southampton into the development of a magnetostrictive thick-film material suitable for use with silicon micromachined devices. This form of magnetostrictive material has previously been deposited onto alumina substrates and this paper reports further work on migrating the technology onto silicon. The evaluation of two alternative glass frits for use as the binder within the thick film is reported. The correct choice of the binder material is important in a thick-film material because it is responsible for binding the active material within the thick film into a composite material and also adhering the film to the substrate. A series of tests have been applied to samples fabricated using various glass frits to assess their mechanical properties and suitability for the micro-actuator applications
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