ENABLING HARDWARE TECHNOLOGIES FOR AUTONOMY IN TINY ROBOTS: CONTROL, INTEGRATION, ACTUATION

The last two decades have seen many exciting examples of tiny robots from a few cm3 to less than one cm3. Although individually limited, a large group of these robots has the potential to work cooperatively and accomplish complex tasks. Two examples from nature that exhibit this type of cooperation are ant and bee colonies. They have the potential to assist in applications like search and rescue, military scouting, infrastructure and equipment monitoring, nano-manufacture, and possibly medicine. Most of these applications require the high level of autonomy that has been demonstrated by large robotic platforms, such as the iRobot and Honda ASIMO. However, when robot size shrinks down, current approaches to achieve the necessary functions are no longer valid. This work focused on challenges associated with the electronics and fabrication. We addressed three major technical hurdles inherent to current approaches: 1) difficulty of compact integration; 2) need for real-time and power-efficient computations; 3) unavailability of commercial tiny actuators and motion mechanisms. The aim of this work was to provide enabling hardware technologies to achieve autonomy in tiny robots. We proposed a decentralized application-specific integrated circuit (ASIC) where each component is responsible for its own operation and autonomy to the greatest extent possible. The ASIC consists of electronics modules for the fundamental functions required to fulfill the desired autonomy: actuation, control, power supply, and sensing. The actuators and mechanisms could potentially be post-fabricated on the ASIC directly. This design makes for a modular architecture. The following components were shown to work in physical implementations or simulations: 1) a tunable motion controller for ultralow frequency actuation; 2) a nonvolatile memory and programming circuit to achieve automatic and one-time programming; 3) a high-voltage circuit with the highest reported breakdown voltage in standard 0.5 μm CMOS; 4) thermal actuators fabricated using CMOS compatible process; 5) a low-power mixed-signal computational architecture for robotic dynamics simulator; 6) a frequency-boost technique to achieve low jitter in ring oscillators. These contributions will be generally enabling for other systems with strict size and power constraints such as wireless sensor nodes.

Relación entre Ansiedad Rasgo, Sensibilidad a la Ansiedad y Síntomas de Ansiedad en Niños y Adolescentes

Sabemos que la ausencia de diagnóstico en la etapa infantil y adolescente de los trastornos de ansiedad favorece que los síntomas se vuelvan crónicos y muchos autores refieren la frecuencia de comorbilidad de síntomas en estas etapas a diferencia de lo que sucede en los adultos lo que dificulta la delimitación psicopatológica de los trastornos de ansiedad. Con un índice de prevalencia de dichos trastornos de ansiedad en la infancia y adolescencia que según autores oscila entre el 15% y 20% y siendo, como señala el profesor Godoy, la ansiedad uno de los problemas más importantes y frecuentes en la etapa infanto-juvenil donde la investigación no ha sido tan prolífica como en la población adulta es donde enmarcamos el presente trabajo. Aceptando que la ansiedad es una respuesta compleja integrada por aspectos internos, situacionales y fisiológicos postulamos la diferencia entre dos constructos teóricos que intervienen en el proceso cuales son la Ansiedad como Rasgo y la Sensibilidad a la Ansiedad; algunos autores consideran que son lo mismo. Hemos utilizado la versión española de SCAS que evalúa trastornos de ansiedad en infancia y adolescencia. Para evaluar la Ansiedad Rasgo utilizamos el STAIC-R y para la evaluación de la Sensibilidad a la Ansiedad en la infancia y adolescencia, existen dos versiones de la escala para adultos (ASI), una adaptada a la población española por Sandín y col. (CASI) y la otra escala, ASIC, que en el presente trabajo hemos validado y que nos ayudará a comprobar nuestras hipótesis, por un lado, que Ansiedad Rasgo y Sensibilidad a la Ansiedad son constructos relacionados pero no idénticos, por otro lado, que Ansiedad Rasgo y Sensibilidad a la Ansiedad se complementan entre sí a la hora de explicar los síntomas de los trastornos de ansiedad. Las garantías psicométricas que aportamos sobre el ASIC la muestran como una escala fiable y válida para evaluar Sensibilidad a la Ansiedad en chicos y chicas así como en niños y adolescentes, convirtiéndola en una herramienta útil para la prevención de Trastornos de Ansiedad, especialmente Trastornos de Pánico con/sin Agorafobia y Trastorno de Ansiedad Generalizada. Por último, la diferencia entre Sensibilidad a la Ansiedad y Ansiedad Rasgo nos permite a nivel de intervención terapéutica aplicar desde la Terapia Cognitivo Conductual, como señala Muris (2015), técnicas específicas para la vulnerabilidad que representa para el sujeto la Sensibilidad a la Ansiedad como la percepción amenazante del entorno por parte del sujeto con elevada Ansiedad Rasgo.

Calibration of the detector flight models for the HERMES and SPIRIT nanosatellite missions

The High Energy Rapid Modular Ensemble of Satellites (HERMES) is a new mission concept involving the development of a constellation of six CubeSats in low Earth orbit with new miniaturized instruments that host a hybrid Silicon Drift Detector/GAGG:Ce based system for X-ray and γ-ray detection, aiming to monitor high-energy cosmic transients, such as Gamma Ray Bursts and the electromagnetic counterparts of gravitational wave events. The HERMES constellation will also operate together with the Australian-Italian SpIRIT mission, which will house a HERMES-like detector. The HERMES pathfinder mini-constellation, consisting of six satellites plus SpIRIT, is likely to be launched in 2023. The HERMES detectors are based on the heritage of the Italian ReDSoX collaboration, with joint design and production by INFN-Trieste and Fondazione Bruno Kessler, and the involvement of several Italian research institutes and universities. An application-specific, low-noise, low-power integrated circuit (ASIC) called LYRA was conceived and designed for the HERMES readout electronics. My thesis project focuses on the ground calibrations of the first HERMES and SpIRIT flight detectors, with a performance assessment and characterization of the detectors. The first part of this work addresses measurements and experimental tests on laboratory prototypes of the HERMES detectors and their front-end electronics, while the second part is based on the design of the experimental setup for flight detector calibrations and related functional tests for data acquisition, as well as the development of the calibration software. In more detail, the calibration parameters (such as the gain of each detector channel) are determined using measurements with radioactive sources, performed at different operating temperatures between -20°C and +20°C by placing the detector in a suitable climate chamber. The final part of the thesis involves the analysis of the calibration data and a discussion of the results.

Cryogenic optical readout for a liquid argon neutrino imaging detector

The GRAIN detector is part of the SAND Near Detector of the DUNE neutrino experiment. A new imaging technique involving the collection of the scintillation light will be used in order to reconstruct images of particle tracks in the GRAIN detector. Silicon photomultiplier (SiPM) matrices will be used as photosensors for collecting the scintillation light emitted at 127 nm by liquid argon. The readout of SiPM matrices inside the liquid argon requires the use of a multi-channel mixed-signal ASIC, while the back-end electronics will be implemented in FPGAs outside the cryogenic environment. The ALCOR (A Low-power Circuit for Optical sensor Readout) ASIC, developed by Torino division of INFN, is under study, since it is optimized to readout SiPMs at cryogenic temperatures. I took part in the realization of a demonstrator of the imaging system, which consists of a SiPM matrix connected to a custom circuit board, on which an ALCOR ASIC is mounted. The board communicates with an FPGA. The first step of the present project that I have accomplished was the development of an emulator for the ALCOR ASIC. This emulator allowed me to verify the correct functioning of the initial firmware before the real ASIC itself was available. I programmed the emulator using VHDL and I also developed test benches in order to test its correct working. Furthermore, I developed portions of the DAQ software, which I used for the acquisition of data and the slow control of the ASICs. In addition, I made some parts of the DAQ firmware for the FPGAs. Finally, I tested the complete SiPMs readout system at both room and cryogenic temperature in order to ensure its full functionality.