DESIGN MODULAR COMMAND AND DATA HANDLING SUBSYSTEM HARDWARE ARCHITECTURES

Over the past few years, On-Board Computing Systems for satellites have been facing a limited level of modularity. Modularity is the ability to reuse and reconstruct the system from a set of predesigned units, with minimal additional engineering effort. CDHS hardware systems currently available have a limited ability to scale with mission needs. This thesis addresses the integration of smaller form factor CDHS modules used for nanosatellites with the larger counterparts that are used for larger missions. In particular, the thesis discusses the interfacing between Modular Computer Systems based on Open Standard commonly used in large spacecrafts and PC/104 used for nanosatellites. It also aims to create a set of layers that would represent a hardware library of COTS-like modules. At the beginning, a review of related and previous work has been done to identify the gaps in previous studies and understand more about Modular Computer Systems based on Open Standard commonly used in large spacecrafts, such as cPCI Serial Space and SpaceVPX. Next, the design requirements have been set to achieve this thesis objectives, which included conducting a prestudy of system alternatives before creating a modular CDHS hardware architecture which was later tested. After, the hardware suitable for this architecture based on the specified requirements was chosen and the PCB was designed based on global standards. Later, several functional tests and communication tests were conducted to assess the practicality of the proposed architecture. Finally, thermal vacuum testing was done on one of the architecture’s layers to test its ability to withstand the space environment, with the aim to perform the vibration testing of the full modular architecture in the future. The aim of this thesis has been achieved after going through several tests, comparing between interfaces, and understanding the process of interfacing between different levels of the CDHS. The findings of this study pave the way for future research in the field and offer valuable insights that could contribute to the development of modular architectures for other satellite subsystems

Acoustic data transmission for embedded software platforms: an empirical study

As microcontrollers become increasingly powerful at a lower cost, they continue to expand to new fields of applications, in particular those under the process of a digital transformation. These systems are often packed with a broad array of complementary subsystems, that can be selectively enabled to further facilitate their integration in larger designs. Due to this immense malleability, they often enable creative problem-solving approaches that not only serve to improve the product’s overall functionality, but may also help to drive down costs even further. This thesis is based on the design and implementation of an embedded software modem system, consisting of a non hardware-native communication interface. The interface is based on the transmission of audio signals and can thus be often implemented with little to no additional hardware costs by utilizing the preexisting functionality of the platform’s features. Under the constraints of the limited computational capabilities of embedded processors, the system works as an efficient communication layer that can be easily integrated into broader software systems concurrently running on these devices. In contrast with signal propagation of wired interfaces, the wireless transmission of acoustic signals brings forth a new set of challenges, which are tackled using sensible strategies based on well-established telecommunication’s theory. Nevertheless, the design approach is largely platform independent, with configurable performance parameters that can be adapted to the available computational resources and system specifications. The proposed architecture is based on the OFDM signalling scheme with QAM-16 carrier modulation and the implementation results show that the system can reliably support up to 32kb/s message transmission speeds for an average interface setup

Energy-efficient embedded machine learning algorithms for smart sensing systems

Embedded autonomous electronic systems are required in numerous application domains such as Internet of Things (IoT), wearable devices, and biomedical systems. Embedded electronic systems usually host sensors, and each sensor hosts multiple input channels (e.g., tactile, vision), tightly coupled to the electronic computing unit (ECU). The ECU extracts information by often employing sophisticated methods, e.g., Machine Learning. However, embedding Machine Learning algorithms poses essential challenges in terms of hardware resources and energy consumption because of: 1) the high amount of data to be processed; 2) computationally demanding methods. Leveraging on the trade-off between quality requirements versus computational complexity and time latency could reduce the system complexity without affecting the performance. The objectives of the thesis are to develop: 1) energy-efficient arithmetic circuits outperforming state of the art solutions for embedded machine learning algorithms, 2) an energy-efficient embedded electronic system for the \u201celectronic-skin\u201d (e-skin) application. As such, this thesis exploits two main approaches: Approximate Computing: In recent years, the approximate computing paradigm became a significant major field of research since it is able to enhance the energy efficiency and performance of digital systems. \u201cApproximate Computing\u201d(AC) turned out to be a practical approach to trade accuracy for better power, latency, and size . AC targets error-resilient applications and offers promising benefits by conserving some resources. Usually, approximate results are acceptable for many applications, e.g., tactile data processing,image processing , and data mining ; thus, it is highly recommended to take advantage of energy reduction with minimal variation in performance . In our work, we developed two approximate multipliers: 1) the first one is called \u201cMETA\u201d multiplier and is based on the Error Tolerant Adder (ETA), 2) the second one is called \u201cApproximate Baugh-Wooley(BW)\u201d multiplier where the approximations are implemented in the generation of the partial products. We showed that the proposed approximate arithmetic circuits could achieve a relevant reduction in power consumption and time delay around 80.4% and 24%, respectively, with respect to the exact BW multiplier. Next, to prove the feasibility of AC in real world applications, we explored the approximate multipliers on a case study as the e-skin application. The e-skin application is defined as multiple sensing components, including 1) structural materials, 2) signal processing, 3) data acquisition, and 4) data processing. Particularly, processing the originated data from the e-skin into low or high-level information is the main problem to be addressed by the embedded electronic system. Many studies have shown that Machine Learning is a promising approach in processing tactile data when classifying input touch modalities. In our work, we proposed a methodology for evaluating the behavior of the system when introducing approximate arithmetic circuits in the main stages (i.e., signal and data processing stages) of the system. Based on the proposed methodology, we first implemented the approximate multipliers on the low-pass Finite Impulse Response (FIR) filter in the signal processing stage of the application. We noticed that the FIR filter based on (Approx-BW) outperforms state of the art solutions, while respecting the tradeoff between accuracy and power consumption, with an SNR degradation of 1.39dB. Second, we implemented approximate adders and multipliers respectively into the Coordinate Rotational Digital Computer (CORDIC) and the Singular Value Decomposition (SVD) circuits; since CORDIC and SVD take a significant part of the computationally expensive Machine Learning algorithms employed in tactile data processing. We showed benefits of up to 21% and 19% in power reduction at the cost of less than 5% accuracy loss for CORDIC and SVD circuits when scaling the number of approximated bits. 2) Parallel Computing Platforms (PCP): Exploiting parallel architectures for near-threshold computing based on multi-core clusters is a promising approach to improve the performance of smart sensing systems. In our work, we exploited a novel computing platform embedding a Parallel Ultra Low Power processor (PULP), called \u201cMr. Wolf,\u201d for the implementation of Machine Learning (ML) algorithms for touch modalities classification. First, we tested the ML algorithms at the software level; for RGB images as a case study and tactile dataset, we achieved accuracy respectively equal to 97% and 83.5%. After validating the effectiveness of the ML algorithm at the software level, we performed the on-board classification of two touch modalities, demonstrating the promising use of Mr. Wolf for smart sensing systems. Moreover, we proposed a memory management strategy for storing the needed amount of trained tensors (i.e., 50 trained tensors for each class) in the on-chip memory. We evaluated the execution cycles for Mr. Wolf using a single core, 2 cores, and 3 cores, taking advantage of the benefits of the parallelization. We presented a comparison with the popular low power ARM Cortex-M4F microcontroller employed, usually for battery-operated devices. We showed that the ML algorithm on the proposed platform runs 3.7 times faster than ARM Cortex M4F (STM32F40), consuming only 28 mW. The proposed platform achieves 15 7 better energy efficiency than the classification done on the STM32F40, consuming 81mJ per classification and 150 pJ per operation

Elektroniikan ja ohjelmiston kehittäminen spektrometrimoduulia varten

A spectrometer is a device that measures properties of light at selected wavelengths. In this thesis, electronics and software are prototyped for a Hamamatsu C12880MA spectrometer module. The aim of the thesis was to design a spectrometer that is customizable according to customer's needs. This was met by designing and building a device and a software that interfaces with the spectrometer module, digitizes the measured spectrum, and transfers it to a computer. Software on the computer displays the spectrum and colorimetric values related to it. The capabilities of the device were tested by measuring various reference light sources, and the results showed that, for the most part, the device was working as expected.Spektrometri on laite, joka mittaa valon ominaisuuksia tietyillä aallonpituuksilla. Tässä työssä kehitettiin elektroniikka ja ohjelmisto Hamamatsu C12880MA -spektrometrimoduulia varten. Työn tavoitteena oli suunnitella spektrometri, joka on mukautettavissa asiakkaan tarpeiden mukaisesti. Työssä suunniteltiin ja rakennettiin laite ja ohjelmisto, jotka toimivat spektrometrimoduulin kanssa, digitoivat mitatun spektrin ja siirtävät sen tietokoneelle. Tietokoneohjelma näyttää mitatun spektrin ja siihen liittyviä kolorimetrisiä arvoja. Laitteen suorituskykyä testattiin mittaamalla eri mittanormaalivalolähteitä, ja saatujen tulosten perusteella laite toimi pääosin odotetulla tavalla

Multilevel Runtime Verification for Safety and Security Critical Cyber Physical Systems from a Model Based Engineering Perspective

Advanced embedded system technology is one of the key driving forces behind the rapid growth of Cyber-Physical System (CPS) applications. CPS consists of multiple coordinating and cooperating components, which are often software-intensive and interact with each other to achieve unprecedented tasks. Such highly integrated CPSs have complex interaction failures, attack surfaces, and attack vectors that we have to protect and secure against. This dissertation advances the state-of-the-art by developing a multilevel runtime monitoring approach for safety and security critical CPSs where there are monitors at each level of processing and integration. Given that computation and data processing vulnerabilities may exist at multiple levels in an embedded CPS, it follows that solutions present at the levels where the faults or vulnerabilities originate are beneficial in timely detection of anomalies. Further, increasing functional and architectural complexity of critical CPSs have significant safety and security operational implications. These challenges are leading to a need for new methods where there is a continuum between design time assurance and runtime or operational assurance. Towards this end, this dissertation explores Model Based Engineering methods by which design assurance can be carried forward to the runtime domain, creating a shared responsibility for reducing the overall risk associated with the system at operation. Therefore, a synergistic combination of Verification & Validation at design time and runtime monitoring at multiple levels is beneficial in assuring safety and security of critical CPS. Furthermore, we realize our multilevel runtime monitor framework on hardware using a stream-based runtime verification language

On-board computers of tware development for PocketQubes

Due to an increasing entry barrier to both universities and researchers in conventional small satellites initiatives, there has been an emergence of smaller and cheaper spacecrafts like PocketQubes, a much more affordable option for public entities. Considering all that, this thesis has been developed as part of a project undertaken by the UPC NanoSat Lab which started as an IEEE GRSS initiative named PoCat. The objective of the PoCat project is to design, develop and test three single unit picosatellites with each featuring the following different payloads, a Video Graphics Array (VGA) camera, a Radio Frequency Interference (RFI) monitoring system at L-band and an RFI monitoring system at K-Band. The three satellites, however, contain the same avionics core composed of the On-Board Computer (OBC), Communication System (COMMS), Attitude Determination and Control System (ADCS) and Electrical Power Supply System (EPS). Given this scenario, the purpose of this report is to give insights regarding the on-board software development for PocketQubes, which as of writing this report there is still room for debate concerning their standardization. Conceptually, the OBC system acts as the brain of the satellite. As for the technology, the OBC is build upon the STM32L476 microcontroller due to its memory storage, power efficiency and processing power. Performing the power management as well as giving response to events are the main objectives of the OBC. In order to do the latter, the flight software is based on a Real-Time Operating System (RTOS) called FreeRTOS which has been selected above other Operating System (OS) due to its predictability, compliance with the required deadlines, support, available documentation, compatibility with previous projects, licensing costs, and certifications. According to FreeRTOS, the program is structured into independent tasks where each one features a priority in line with their criticality. Then, the project is constituted by eight tasks, with five designed to operate the subsystems of the satellite, one for memory writing purposes and the remaining two are devoted to implement FreeRTOS software timers. Furthermore, tasks can communicate with each other by means of task notifications or event groups, both being software tools provided by the operating system

Low-cost real-time motion capturing system using inertial measurement units

Human movement modeling - also referred to as motion-capture - is a rapidly expanding field of interest for medical rehabilitation, sports training, and entertainment. Motion capture devices are used to provide a virtual 3-dimensional reconstruction of human physical activities - employing either optical or inertial sensors. Utilizing inertial measurement units and digital signal processing techniques offers a better alternative in terms of portability and immunity to visual perturbations when compared to conventional optical solutions. In this paper, a cable-free, low-cost motion-capture solution based on inertial measurement units with a novel approach for calibration is proposed. The goal of the proposed solution is to apply motion capture to the fields that, because of cost problems, did not take enough benefit of such technology (e.g., fitness training centers). According to this goal, the necessary requirement for the proposed system is to be low-cost. Therefore, all the considerations and all the solutions provided in this work have been done according to this main requirement

Automotive Control Catalyzer to Synthetize CaCO3 from Residual Co2 Embedded Control System

La contaminación generada por el sector automotriz es un problema de medio ambiente por el que sectores gubernamentales y privados han tomado acciones para contrarrestarla. Uno de esos esfuerzos procura de proveer una solución para la emisión de gases de producidos de diferentes sistemas de combustión. El objetivo del presente proyecto es diseñar un sistema de alta calidad y confiable, capaz de transformar una cantidad considerable de los gases emitidos en nuevo combustible antes de ser liberados de vuelta al entorno. El módulo de control fue desarrollado considerando los requerimientos demandados por la industria automotriz. El controlador fue basado sobre la arquitectura AUTOSAR, este también incluyó el protocolo de comunicación estándar CAN 2.0 desempeñado con el microcontrolador validado como grado 2 por el Consejo de Electrónica Automotriz, y el sensor SHT11 usado fue certificado contra RoHS. La arquitectura de software cumple con la complejidad inherente de las especificaciones de AUTOSAR, por consiguiente, diferentes técnicas fueron requeridas para su solución, incluyendo la definición, diagramas de límites, especificación de requerimientos, interfaces de software e interacción de módulos. Una vez que los requerimientos fueron conocidos, el código fue implementado. Como resultado, este módulo puede ser categorizado como un producto de grado automotriz que puede ser introducido en el mercado automotriz.The pollution generated by the automotive sector has been an environmental issue in the latest years, and nowadays, different governmental and private sectors have taken actions on this matter. One of these efforts tries to provide a solution for contaminating gas emissions produced from different fuel combustion systems. The aim of the present project is to design a reliable and high-quality system that senses the environmental temperature, relative humidity, and calculates the dew point to control a catalyzer capable of transforming a considerable amount of exhaust gases into a new fuel component before they are released back into the environment. The control module was developed considering the requirements demanded by the automotive industry. The controller was based on an AUTOSAR architecture, it also included the standard CAN 2.0 communication protocol performed within the microcontroller validated as grade 2 by the Automotive Electronics Council, and the SHT11 sensor used was certified against RoHS. Equally important, the software architecture complied with the complexity inherent in AUTOSAR specifications. Therefore, different techniques were required for its solution, including, boundary diagram, requirement specifications, software interface, and module interaction definitions. Once these requirements where met, the code was implemented. As a result, this module could be categorized as an automotive-grade product that can be introduced in the automotive market.Consejo Nacional de Ciencia y Tecnologí

Circuits and Systems Advances in Near Threshold Computing

Modern society is witnessing a sea change in ubiquitous computing, in which people have embraced computing systems as an indispensable part of day-to-day existence. Computation, storage, and communication abilities of smartphones, for example, have undergone monumental changes over the past decade. However, global emphasis on creating and sustaining green environments is leading to a rapid and ongoing proliferation of edge computing systems and applications. As a broad spectrum of healthcare, home, and transport applications shift to the edge of the network, near-threshold computing (NTC) is emerging as one of the promising low-power computing platforms. An NTC device sets its supply voltage close to its threshold voltage, dramatically reducing the energy consumption. Despite showing substantial promise in terms of energy efficiency, NTC is yet to see widescale commercial adoption. This is because circuits and systems operating with NTC suffer from several problems, including increased sensitivity to process variation, reliability problems, performance degradation, and security vulnerabilities, to name a few. To realize its potential, we need designs, techniques, and solutions to overcome these challenges associated with NTC circuits and systems. The readers of this book will be able to familiarize themselves with recent advances in electronics systems, focusing on near-threshold computing

Near Sensor Artificial Intelligence on IoT Devices for Smart Cities

The IoT is in a continuous evolution thanks to new technologies that open the doors to various applications. While the structure of the IoT network remains the same over the years, specifically composed of a server, gateways, and nodes, their tasks change according to new challenges: the use of multimedia information and the large amount of data created by millions of devices forces the system to move from the cloud-centric approach to the thing-centric approach, where nodes partially process the information. Computing at the sensor node level solves well-known problems like scalability and privacy concerns. However, this study’s primary focus is on the impact that bringing the computation at the edge has on energy: continuous transmission of multimedia data drains the battery, and processing information on the node reduces the amount of data transferred to event-based alerts. Nevertheless, most of the foundational services for IoT applications are provided by AI. Due to this class of algorithms’ complexity, they are always delegated to GPUs or devices with an energy budget that is orders of magnitude more than an IoT node, which should be energy-neutral and powered only by energy harvesters. Enabling AI on IoT nodes is a challenging task. From the software side, this work explores the most recent compression techniques for NN, enabling the reduction of state-of-the-art networks to make them fit in microcontroller systems. From the hardware side, this thesis focuses on hardware selection. It compares the AI algorithms’ efficiency running on both well-established microcontrollers and state-of-the-art processors. An additional contribution towards energy-efficient AI is the exploration of hardware for acquisition and pre-processing of sound data, analyzing the data’s quality for further classification. Moreover, the combination of software and hardware co-design is the key point of this thesis to bring AI to the very edge of the IoT network