Space science and exploration has become more accessible in recent years due to the popularization of the concept of CubeSats. Twenty years ago CubeSats were developed as a concept model that intended to involve universities to participate on space missions. It rapidly caught the attention of researchers, space agencies, governments, and companies because of the specifics on size and weight requirements meant that targeted missions could be designed, developed and launched with a significant reduction of costs. The development of more intricated target missions has forced a shift on the traditional notion of using a centralized control architecture to an architecture that is distributed, due to the fact that once the CubeSat is launched there is no way of providing maintenance to if it loses functionality over the control unit. One of the ways the space industry has been doing this shift is by means of multi-agent systems. The Multi-Agent Systems Framework for Embedded Systems (MAES) was developed with the intention of providing the developer with a tool to implement real-time Multi-Agent System (MAS) based applications in embedded environments. Something that the market is lacking, especially for the development of real-time applications in the space industry using distributed architectures.In this thesis the MAES framework was extended so it is now capable to perform inter-platform communication. So, the control unit architecture can be broaden allowing agents from different platforms to interact and perform cooperatively different routines designed by the developer, so it is not limited to the capabilities of just one platform. I2C was chosen as the communication protocol due to its scalability, ability to arbitrate messages and low implementation complexity. The implementation of the inter-platform communication protocol was conducted using the same hardware and real-time operating system that was used for the design of MAES framework to assure that there were no behaviour changes from the framework. The extension of the capabilities of MAES framework was done by adding the Agent Communication Channel (ACC), following the guidelines from the Foundation for Intelligent Physical Agents (FIPA). The performance of the designed protocol was evaluated by developing a proof-of-concept system based on Texas Instruments MSP432P401R SimpleLink Microcontroller LaunchPad, which is a commercial off-the-shelf hardware platform. The measurements from the experimental setup show a consistent precision of the message round trip time in case of two intercommunicating platforms. Also, the relation between the number of agents accessing simultaneously the I2C bus and the delay was determined. It was determined that the relationship between the delay of the exchange of inter-platform messages increases linearly with the number of agents that are simultaneously sending messages on the I2C bus while saturation is not reached.
La scienza spaziale e l'esplorazione sono diventate più accessibili negli ultimi anni a causa della divulgazione del concetto di CubeSats. Venti anni fa CubeSats è stato sviluppato come un modello concettuale che intendeva coinvolgere le università a partecipare alle missioni spaziali. Ha rapidamente attirato l'attenzione di ricercatori, agenzie spaziali, governi e aziende a causa delle specifiche relative alle dimensioni e al peso richieste che hanno consentito di progettare, sviluppare e lanciare missioni mirate con una significativa riduzione dei costi. Lo sviluppo di missioni target più complesse ha costretto a spostare la nozione tradizionale di utilizzare un'architettura di controllo centralizzata a un'architettura distribuita, poiché una volta lanciato CubeSat non è possibile fornire manutenzione se perde funzionalità sopra l'unità di controllo. Uno dei modi in cui l'industria spaziale ha fatto questo cambiamento è attraverso sistemi multi-agente. Il framework di sistemi multi-agente per sistemi embedded (MAES) è stato sviluppato con l'intento di fornire allo sviluppatore uno strumento per implementare applicazioni basate su sistemi multi-agente (MAS) in tempo reale in ambienti embedded. Qualcosa che manca al mercato, in particolare per lo sviluppo di applicazioni in tempo reale nel settore spaziale utilizzando architetture distribuite.In questa tesi il framework MAES è stato ampliato e ora è in grado di eseguire comunicazioni tra piattaforme. L'architettura delle unità di controllo può quindi essere ampliata consentendo agli agenti di piattaforme diverse di interagire ed eseguire routine cooperativamente diverse progettate dallo sviluppatore, quindi non si limita alle funzionalità di un'unica piattaforma. I2C è stato scelto come protocollo di comunicazione a causa della sua scalabilità, capacità di arbitrare messaggi e bassa complessità di implementazione. L'implementazione del protocollo di comunicazione tra piattaforme è stata condotta utilizzando lo stesso sistema operativo hardware e in tempo reale utilizzato per la progettazione del framework MAES per garantire che non vi siano cambiamenti di comportamento dal framework. L'estensione delle funzionalità del framework MAES è stata effettuata aggiungendo l'Agent Communication Channel (ACC), seguendo le linee guida della Foundation for Intelligent Physical Agents (FIPA). Le prestazioni del protocollo progettato sono state valutate sviluppando un sistema proof-of-concept basato su Texas Instruments MSP432P401R SimpleLink Microcontroller LaunchPad, che è una piattaforma hardware commerciale immediatamente disponibile. Le misurazioni effettuate con la configurazione sperimentale mostrano una precisione costante del tempo di andata e ritorno del messaggio in caso di due piattaforme intercomunicanti. Inoltre, è stata determinata la relazione tra il numero di agenti che accedono contemporaneamente al bus I2C e il ritardo. È stato determinato che la relazione tra il ritardo dello scambio di messaggi tra piattaforme aumenta linearmente con il numero di agenti che inviano contemporaneamente messaggi sul bus I2C mentre la saturazione non viene raggiunta.
A communication protocol design for multi-agent systems framework for embedded systems (MAES) based platforms
INTERIANO, SAMANTHA
2017/2018
Abstract
Space science and exploration has become more accessible in recent years due to the popularization of the concept of CubeSats. Twenty years ago CubeSats were developed as a concept model that intended to involve universities to participate on space missions. It rapidly caught the attention of researchers, space agencies, governments, and companies because of the specifics on size and weight requirements meant that targeted missions could be designed, developed and launched with a significant reduction of costs. The development of more intricated target missions has forced a shift on the traditional notion of using a centralized control architecture to an architecture that is distributed, due to the fact that once the CubeSat is launched there is no way of providing maintenance to if it loses functionality over the control unit. One of the ways the space industry has been doing this shift is by means of multi-agent systems. The Multi-Agent Systems Framework for Embedded Systems (MAES) was developed with the intention of providing the developer with a tool to implement real-time Multi-Agent System (MAS) based applications in embedded environments. Something that the market is lacking, especially for the development of real-time applications in the space industry using distributed architectures.In this thesis the MAES framework was extended so it is now capable to perform inter-platform communication. So, the control unit architecture can be broaden allowing agents from different platforms to interact and perform cooperatively different routines designed by the developer, so it is not limited to the capabilities of just one platform. I2C was chosen as the communication protocol due to its scalability, ability to arbitrate messages and low implementation complexity. The implementation of the inter-platform communication protocol was conducted using the same hardware and real-time operating system that was used for the design of MAES framework to assure that there were no behaviour changes from the framework. The extension of the capabilities of MAES framework was done by adding the Agent Communication Channel (ACC), following the guidelines from the Foundation for Intelligent Physical Agents (FIPA). The performance of the designed protocol was evaluated by developing a proof-of-concept system based on Texas Instruments MSP432P401R SimpleLink Microcontroller LaunchPad, which is a commercial off-the-shelf hardware platform. The measurements from the experimental setup show a consistent precision of the message round trip time in case of two intercommunicating platforms. Also, the relation between the number of agents accessing simultaneously the I2C bus and the delay was determined. It was determined that the relationship between the delay of the exchange of inter-platform messages increases linearly with the number of agents that are simultaneously sending messages on the I2C bus while saturation is not reached.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/144708