Biblio

This paper presents a method optimizing the thrust force of a Micro Electro Mechanical System (MEMS) Permanent Magnet Linear Motor, based on harmonic current injection. Fourier decomposition is implemented to the air gap flux density of the motor to derive the fitting expression of the thrust force dependent to exciting current. Through analyzing the thrust force ripple of sinusoidal current excitement, the paper comes up with the strategy of harmonic current injection to eliminate the ripple component in the thrust force waveform. Mathematical demonstration is given that injecting harmonic current can totally eliminate the ripple caused by odd component of vertical air gap magnetic induction intensity. Simulation verification is implemented based on the 3rd and 7th harmonic injection control strategy, proving that the method is feasible for the thrust ripple is reduced to 4.3% of the value before optimazation. Experimental results lead to the consistent conclusion that the strategy shows good steady-state and dynamic performance.

This paper is the first to investigate the long-term stability of Surface Acoustic Wave Gyroscopes (SAWG) using an ovenized control system. Monolithic integration of a MEMS heater adjacent to SAW devices on Lithium Niobate over insulator substrate (LNOI) tightly couples frequency-based temperature detection with heating for temperature and frequency stabilization. This first prototype demonstrates the ability to minimize the temperature variations of the SAWG to below ±10 μK and stabilize the SAWG resonance frequency to ±0.2 ppm. This approach thus eliminates the thermal drift in a SAWG and enables the development of a new generation of MEMS-based gyroscopes with long-term stability.

This paper presents a new class of high-performance permanent micro-magnets based on the controlled assembly of cobalt nanorods for the electromagnetic transduction of MEMS. Micromagnets are fabricated using a low temperature fabrication process that yields a dense material exhibiting high coercive field and remanence to saturation magnetization ratio. The cartography of the magnetic induction produced by the sub-millimeter size magnets was obtained using a scanning Hall effect micro-probe microscope. Silicon microcantilevers placed in the vicinity of these magnets were successfully actuated using the Lorentz force with low currents. The good signal to noise ratio measured at resonance demonstrates the potentiality of these nanostructured micro-magnets.

In this paper, a distributed architecture for the implementation of smart city has been proposed to facilitate various smart features like solid waste management, efficient urban mobility and public transport, smart parking, robust IT connectivity, safety and security of citizens and a roadmap for achieving it. How massive volume of IoT data can be analyzed and a layered architecture of IoT is explained. Why data integration is important for analyzing and processing of data collected by the different smart devices like sensors, actuators and RFIDs is discussed. The wireless sensor network can be used to sense the data from various locations but there has to be more to it than stuffing sensors everywhere for everything. Why only the sensor is not sufficient for data collection and how human beings can be used to collect data is explained. There is some communication protocols between the volunteers engaged in collecting data to restrict the sharing of data and ensure that the target area is covered with minimum numbers of volunteers. Every volunteer should cover some predefined area to collect data. Then the proposed architecture model is having one central server to store all data in a centralized server. The data processing and the processing of query being made by the user is taking place in centralized server.