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Project: INSPECT - Integrated Nano Sensor Probes and Electronics for Eddy Currents Testing

Acronym: INSPECT
Main Objective:
This research proposal aims to develop a state of the art Non-Destructive Testing (NDT) system to overcome current testing limitations on some specific industrial applications. The system will include a new eddy currents probe, combining coils, a Magnetoresistive (MR) sensors array and Complementary Metal-Oxide Semiconductor (CMOS) microelectronic circuits, which will work together with an eddy current generation element. Since the probe aims to be efficient for both superficial (requiring high frequency operation) and buried defects (requiring low frequency operation), coils have the disadvantage of having a frequency dependent sensitivity, which is lower at low frequencies. Moreover, coils also have a low spatial resolution, due to its millimeters range size. While coils measure magnetic flux, MR sensors measure magnetic field thus having a frequency independent sensitivity. Therefore, by adding MR sensors to the probe, its scope of detection increases, and also its spatial resolution, since MR sensors can have dimensions on the micrometer range. Other advantage of MR sensors is the fact that they are usually produced using thin film technology allowing high resolution and repeatability. In order to increase the number of MR sensors in the probe, CMOS microelectronic circuits will be included to perform multiplexing and therefore reducing the number of outputs. The CMOS circuit will also bias the MR sensors, and apply low-noise amplification and filtering. To cope with the new probe high data throughput, the system will also include an high performance Digital Signal Processing (DSP) unit. The DSP unit will be based on a Field-Programmable Gate Array (FPGA) and high speed and resolution data converters. A scalable processing architecture will explore high parallelism within the FPGA processing core to perform digital demultiplexing, filtering and demodulation of the multiple sensors signals. Also, the DSP unit will configure the gain, bandwidth and the sensors addressing mechanism by communicating with the microelectronic circuits. Results will be displayed in a Graphical User Interface (GUI) running on a computer connected with the developed system. Characterization and testing on real and relevant NDT applications will evaluate the new system performance.
Reference: PTDC/EEI-PRO/3219/2012 (P.1206)
Funding: FCT/PTDC
Start Date: 01-05-2013
End Date: 01-11-2015
Team: Pedro Miguel Pinto Ramos, José Augusto Alves Gouveia, Luís Filipe Soldado Granadeiro Rosado
Groups: Instrumentation and Measurements – Lx
Partners: Fundação da Faculdade de Ciências e Tecnologia (FFCT/FCT/UNL), INESC-ID, INESC-MN
Local Coordinator: Pedro Miguel Pinto Ramos

Associated Publications