Evaluation Methods of Mechanical Properties of Micro-Sized Specimens

Micro-sized components have been widely used to microelectromechanical systems (MEMSs) and medical apparatus in recent years. Measurement methodologies of the mechanical property of small materials need to be improved for structural designing of these devices because of their component size reduced to micro- or nano-regime where sample size effects emerge. Mechanical properties and deformation behavior could be very different with their dimensions and geometries especially for small materials. Our experiments on the micro-specimen tested in different dimensions and loading directions are suitable for the evaluations of materials for MEMS components. In this chapter, recent studies on micro-testing of bending, compression, and tension with micro-sized samples will be presented including fabrication methods of non-tapered micro-sized specimens

Inertial MEMS: readout, test and application

This thesis moves towards the investigation of Micro Electro-Mechanical Systems (MEMS) intertial sensors from different perspectives and points of view: readout, test and application. Chapter 1 deals with the state-of-the-art for the interfaces usually employed for 3- axes micromachined gyroscopes. Several architecture based on multiplexing schemes in order to extremely simplify the analog front-end which can be based on a single charge amplifier are analysed and compared. A novel solution that experiments an innovative readout technique based on a special analog-Code Division Multiplexing Access (CDMA) is presented; this architecture can reach a considerable reduction of the Analog Front-End (AFE) with reference to other multiplexing schemes. Many family codes have been considered in order to find the best trade-off between performance and complexity. System-level simulations prove the effectiveness of this technique in processing all the required signals. A case study is also analysed: a comparison with the SD740 micro-machined integrated inertial module with tri-axial gyroscope by SensorDynamics AG is provided. MEMS accelerometers are widely used in the automotive and aeronautics fields and are becoming extremely popular in a wide range of consumer electronics products. The cost of testing is a major one within the manufacturing process, because MEMS accelerometer characterization requires a series of tests that include physical stimuli. The calibration and the functional testing are the most challenging and a wide selection of Automatic Test Equipments (ATEs) is available on the market for this purpose; those equipments provide a full characterization of the Device Under Test (DUT), from low-g to high-g levels, even over temperature. Chapter 2 presents a novel solution that experiments an innovative procedure to perform a characterization at medium-g levels. The presented approach can be applied to low-cost ATEs obtaining challenging results. The procedure is deeply investigated and an experimental setup is described. A case study is also analysed: some already trimmed Three Degrees of Freedom (3DoF)-Inertial Measurement Unit (IMU) modules (three-axes accelerometer integrated with a mixed signal ASIC), from SensorDynamics AG are tested with the experimental setup and analysed, for the first time, at medium-g levels. Standard preprocessing techniques for removing the ground response from vehicle- mounted Ground Penetrating Radar (GPR) data may fail when used on rough terrain. In Chapter 3, a Laser Imaging Detection and Ranging (LIDAR) system and a Global Positioning System (GPS)/IMU is integrated into a prototype system with the GPR and provided high-resolution measurements of the ground surface. Two modifications to preprocessing were proposed for mitigating the ground bounce based on the available LIDAR data. An experiment is carried out on a set of GPR/LIDAR data collected with the integrated prototype vehicle over lanes with artificially rough terrain, consisting of targets buried under or near mounds, ruts and potholes. A stabilization technique for multi-element vehicle-mounted GPR is also presented

Analog-CMDA based interfaces for MEMS gyroscopes

This work moves toward the state-of-the-art for the interfaces usually employed for three-axes micromachined gyroscopes. Several architectures based on multiplexing schemes in order to extremely simplify the analog front-end which can be based on a single charge amplifier are analyzed and compared. This paper presents a novel solution that experiments an innovative readout technique based on a special analog-CDMA (Code Division Multiplexing Access); this architecture can reach a considerable reduction of the analog front-end with reference to other multiplexing schemes. Many family codes have been considered in order to find the best trade-off between performance and complexity. System-level simulations prove the effectiveness of this technique in processing all the required signals. Finally, a case study is analyzed: a comparison with the SD740 micro-machined integrated inertial module with a tri-axial gyroscope by SensorDynamics AG is provided