Design, Modeling and Integration of High Sensitive Accelerometers with Adaptive and Non-Linear Control Targeted on FPGA
The countless number of applications urged a demand for high performance micro-accelerometers, which in turn continue to gain momentum. Within that framework, one must justify the need for an approach defined by a system level performance in closed loop integration, by understanding the current performance limitations in the state-of-the-art micro-accelerometers, in research, on the market, and when employed with other electrical components.
MEMS-based devices became smaller and faster, but their real advantage is the low cost, consequence of the use of batch fabrication processes originally adapted from the manufacturing of integrated circuits. Nevertheless, depending on the targeted application, this revolution in technology is constrained by many factors limiting the usage of the micro-devices. Some of these boundaries and limitations come from the sensor itself such as, pull-in voltages, non-linearities, dynamic range, and sensitivity while other boundaries could include packaging, surrounding elements such as integrated CMOS readout circuits and digital controllers.
To overcome these constraints and limitations, one may target improvements at the sensor level exploiting the latest fabrication advances, increasing sensitivity and lowering the noise floor, by incorporating a bulky proof mass for example. However this approach could be costly and high aspect ratios are difficult to achieve. Another approach is to employ smart and robust controllers, in a closed-loop control operating mode. In addition, for system level efficiency, speed, resolution, parallelism and cost, the controller could be targeted on a flexible, reconfigurable technology such as FPGAs.
The objective of this project is to investigate the limitations of current analog and digital closed-loop control techniques and propose novel methodologies, that are easy to implement on FPGA and able to achieve maximum sensitivity of the targeted closed-loop accelerometer without increasing the cost of the fabrication methodology.
Industrial applications that can benefit from such high sensitivity are related to active suspension, adaptive brakes, microgravity measurements, inertial navigation, seismology and guidance, building monitoring, oil explorations and non-invasive surgery.