This thesis presents the preliminary design of a locomotion system for a mobile rover deployed on the asteroid (4) Vesta, combining in-situ exploration with sample-return capabilities. Small Solar System Bodies (SSSBs) like Vesta act as archives of early Solar System evolution and planet formation; however, their harsh environments, characterized by microgravity, the lack of an atmosphere, and highly uncertain surface mechanical properties, pose severe engineering challenges for stable surface mobility. Traditional locomotion systems designed for planetary exploration face significant risks of slippage, capsizing, or escaping into space due to low local gravity and irregular gravitational fields. To determine the optimal mobility architecture, a systematic trade-off analysis using the Analytical Hierarchy Process (AHP) was conducted across four candidate locomotion technologies; the modified wheeled rover configuration was selected as the baseline solution for its robust, adaptable performance and high safety margins. The resulting locomotion design incorporates a 6x6x6 architecture with six wheel-walking capabilities, heavily drawing upon the design heritage of JAXA’s MMX rover and ESA’s Rosalind Franklin (ExoMars) rover. The architecture consists of an optimized, rigid alu minum alloy wheel design featuring curved grousers to prevent soil sinkage and maximize tractive efficiency, paired with a highly adaptable triple-bogie suspension system to en sure continuous ground contact on rough and uneven terrain. The structural integrity and mass minimization of the wheel disk and suspension beams were verified using Finite Element Method (FEM) static analysis under worst-case loading configurations. Built from high-strength aluminum alloy, the complete locomotion system has a total mass of approximately 25 Kg and utilizes high-torque electromechanical actuators. It features two distinct operational states: a stowed configuration for compact transport and an active operating configuration; and supports precise driving, steering, and active wheel walking modes. Backed by experimental test data from granular soil simulants, this design demonstrates a highly reliable, low-power solution for navigating challenging extraterres trial surfaces, ensuring successful multi-point scientific sampling on Vesta.
Questa tesi presenta il progetto preliminare di un sistema di locomozione per un rover mobile destinato all’asteroide (4) Vesta, combinando esplorazione in-situ e capacità di ri torno di campioni. I corpi celesti di piccole dimensioni, come Vesta, rappresentano archivi dell’evoluzione del Sistema Solare e della formazione dei pianeti; tuttavia, i loro ambienti ostili, caratterizzati da microgravità, assenza di atmosfera e proprietà meccaniche incerte, pongono sfide ingegneristiche per una mobilità stabile. I sistemi di locomozione tradizion ali progettati per l’esplorazione planetaria affrontano rischi di slittamento, ribaltamento o di fuga nello spazio a causa della bassa gravità locale e dei campi gravitazionali irregolari. Per determinare l’architettura ottimale, è stata condotta un’analisi comparativa con il metodo Analytical Hierarchy Process (AHP) su quattro tecnologie candidate; la configu razione di modified wheeled rover è stata selezionata come soluzione di riferimento grazie alle sue prestazioni robuste e adattabili e agli elevati margini di sicurezza. Il progetto integra un’architettura 6x6x6 con capacità di wheel-walking, ispirata all’eredità del rover MMX della JAXA e del rover Rosalind Franklin (ExoMars) dell’ESA. L’architet tura consiste in ruote rigide in lega di alluminio, dotate di grousers curvi per prevenire l’affondamento nel terreno e massimizzare l’efficienza di trazione, abbinate a un sistema di sospensione triple-bogie adatto a garantire un contatto continuo con il suolo su terreni accidentati e irregolari. L’integrità strutturale e la minimizzazione della massa del disco ruota e dei bracci della sospensione sono state verificate mediante analisi statica degli elementi finiti nelle configurazioni di carico peggiori. Realizzato in lega di alluminio ad alta resistenza, il sistema completo di locomozione ha una massa totale di circa 25 Kg e utilizza attuatori elettromeccanici ad alta coppia. Presenta due distinti stati operativi: una configurazione ripiegata per il trasporto e una configurazione attiva operativa; inoltre supporta modalità di guida, sterzata e wheel-walking. Supportato da dati sperimentali ottenuti tramite test su simulanti granulari, questo progetto dimostra una soluzione affid abile e a basso consumo energetico per la navigazione su superfici extraterrestri complesse, garantendo il successo di campagne scientifiche di campionamento multiplo su Vesta
Preliminary design of the locomotion system of a rover for an asteroid exploration mission
Giardini, Chiara
2025/2026
Abstract
This thesis presents the preliminary design of a locomotion system for a mobile rover deployed on the asteroid (4) Vesta, combining in-situ exploration with sample-return capabilities. Small Solar System Bodies (SSSBs) like Vesta act as archives of early Solar System evolution and planet formation; however, their harsh environments, characterized by microgravity, the lack of an atmosphere, and highly uncertain surface mechanical properties, pose severe engineering challenges for stable surface mobility. Traditional locomotion systems designed for planetary exploration face significant risks of slippage, capsizing, or escaping into space due to low local gravity and irregular gravitational fields. To determine the optimal mobility architecture, a systematic trade-off analysis using the Analytical Hierarchy Process (AHP) was conducted across four candidate locomotion technologies; the modified wheeled rover configuration was selected as the baseline solution for its robust, adaptable performance and high safety margins. The resulting locomotion design incorporates a 6x6x6 architecture with six wheel-walking capabilities, heavily drawing upon the design heritage of JAXA’s MMX rover and ESA’s Rosalind Franklin (ExoMars) rover. The architecture consists of an optimized, rigid alu minum alloy wheel design featuring curved grousers to prevent soil sinkage and maximize tractive efficiency, paired with a highly adaptable triple-bogie suspension system to en sure continuous ground contact on rough and uneven terrain. The structural integrity and mass minimization of the wheel disk and suspension beams were verified using Finite Element Method (FEM) static analysis under worst-case loading configurations. Built from high-strength aluminum alloy, the complete locomotion system has a total mass of approximately 25 Kg and utilizes high-torque electromechanical actuators. It features two distinct operational states: a stowed configuration for compact transport and an active operating configuration; and supports precise driving, steering, and active wheel walking modes. Backed by experimental test data from granular soil simulants, this design demonstrates a highly reliable, low-power solution for navigating challenging extraterres trial surfaces, ensuring successful multi-point scientific sampling on Vesta.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/260576