PUBLICATIONS

Author: Sharma, Kiran (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Microelectronics)

Contributor: Verhoeven, C.J.M. (mentor)

Degree granting institution: Delft University of Technology

Programme: Electrical Engineering | Signals and Systems

Date: 18 Januari 2018

Abstract: The Moon is earth’s only natural satellite, it has no atmosphere, no life. The days are nearly burning,
the nights are freezing. It is old and cratered, smooth and young. Yet, curiosity and desire to explore
the uncertainty has driven man to find scientific truth. Here comes a small “Nano rover” from TU
Delft!
TU Delft, Netherlands and Indian Institute of Science, Bangalore, India are working towards an
opportunity to land a space robot called “Nano Rover” on the Moon in collaboration with Indian Space
Research Organisation (ISRO), Bangalore, India. The prime objective of the mission is that the rover
should navigate on the Moon surface. The secondary objective is to capture photos intermittently
and send the data to the earth. Considering the mass and time constraints, the existing terrestrial
Zebro robot was proposed to be chosen for this purpose. However, Zebro is designed for terrestrial
applications and it has to be adapted to the extreme environment conditions on the lunar surface and
earth-moon transit orbit where the temperature can go as low as −180◦ C. Thus, it is quite challenging
to modify the existing Zebro to suite the requirements for extra-terrestrial applications. Hence, a
detailed study of lunar environment is necessary along with the extensive study on the adaptability of
Zebro to be lunar compliant. This thesis presents (i) a literature study on the environment conditions
on the Moon and during earth-moon transit orbit (ii) analysis of the existing Zebro and lists the
requirements to adapt it to be lunar compliant (iii) conduct tests on materials, components and
elements to enable usage of them for lunar and transit orbit environment (iv) design, develop and
test the On Board Computer for lunar compatible Zebro and (v) demonstrate the locomotion of the
robot on a simulated lunar terrain.
There are three major challenges in conceptualizing and realizing the Nano Rover – (i) stringent mission
management (ii) adapting it to the hostile environment such as temperature, vacuum, radiation,
vibration, shock (iii) strict product assurance needs. This thesis has comprehensively addressed these
challenges and successfully adapted the existing terrestrial Zebro as Nano Rover. Highly reliable
electronic components were chosen, tested, and used them in designing the locomotion system. A
lunar complaint On Board Computer and a motor drive system were successfully realized meeting
all the lunar mission needs. The prototype was tested successfully under extreme simulated lunar
environment conditions and locomotion on a simulated lunar terrain was successfully demonstrated.

Title: Design of the locomotion subsystem for the Lunar Zebro: A design and implementation to ensure that Zebro can thrive on the moon

Author: Miog, Jeffrey (TU Delft Electrical Engineering, Mathematics and Computer Science)

Contributor: Verhoeven, Chris (mentor)

Degree granting institution: Delft University of Technology

Date: 22 Augustus 2018

 Abstract: This report covers the development of the Locomotion system for the Lunar Zebro that is responsible for the positioning control of the six legs and the operating of the solar panel. It covers the initial problem analysis, requirement discovery, conceptual design, part identification for implementation, implementation and the first tests, their results, and the design improvement recommendations. The electronics consist of Commercial Off The Shelf Components with a short delivery time in order to meet the strict deadline. These components are not rated for their radiation performance, but test results for the operation of these components in radiated environments are publicly available. Components were selected and implemented in the design based on these test-results. The implementation of the design was tested at a radiation facility to ensure that the design meets the total radiation dose requirements.

Author: Rouwen, Floris (TU Delft Electrical Engineering, Mathematics and Computer Science)

Contributor: Verhoeven, Chris (mentor); van Genderen, Arjan (graduation committee)

Degree granting institution: Delft University of Technology

Project: The Zebro Project

Date: 27 Augustus 2018

Abstract: The TU Delft ZEs-Benige RObot (Zebro) project is presented with the opportunity to bring the Zebro concept to the surface of our moon. To maximise the probability of success, the Locomotion Sub-System (LSS) software of Lunar Zebro is developed using a novel model-driven design tool called Dezyne. Dezyne uses a proprietary language to describe systems, perform model checking and execute source code generation. Dezyne is proposed for this thesis as it can improve the quality of the LSS design. This is required because the project is under strict time- and manpower constraints. The goals for this thesis are:
i. Deliver a reliable software design for the Locomotion Sub-System (LSS) of Lunar Zebro.
ii. Deliver a working implementation of the Locomotion Sub-System (LSS) software design on Lunar Zebro’s hardware.
iii. Investigate the advantages and disadvantages of the use of the model-driven software design tool Dezyne.

The current workhorse of the Zebro Project, is a Zebro called DeciZebro. Lunar Zebro builds on the legacy of the design of DeciZebro. The LSS of Lunar Zebro consists of an Locomotion
Controller (LC) and six leg modules. The requirements of the LSS software of Lunar Zebro are derived from the requirements of Lunar Zebro as a whole. These requirements are categorised according an European Space Agency (ESA) standard.

With the help of Dezyne, the system is designed, verified, simulated and integrated into native code. It is found that Dezyne is not suitable for designing the software of the leg modules.
Therefore, the LC consists primarily of generated code, while the leg modules solely contain code developed by hand.

The goals of this thesis are partly reached. An LSS software implementation is delivered with the use of Dezyne. However, the design is lacking a framework in which errors that occur
during operation can be resolved by means of extensive state machining. This is due to time constraints. Additionally, it is unclear if this specific LSS software implementation is more reliable than an implementation that is made without the use of Dezyne. The third goal, listing the advantages and disadvantages of Dezyne, is fulfilled.

Author: G.M. ter Horst

Contributor: K.G. Langendoen & A. Noroozi C.J.M. & Verhoeven

Degree granting institution: Delft University of Technology

Program: Electrical Engineering | Embedded Systems

Date: 12 March 2019

Abstract: A robot swarm of zebros (Dutch: ZEs Benige RObots) is being developed at the TU Delft, with the purpose of forming a large self-deploying sensor network that survey remote locations without the need for any pre-existing infrastructure, or be used for evaluating swarming algorithms in the field. Towards this goal, zebros need to be able to communicate with and localise nearby neighbours. Existing localisation solutions showed to be inadequate for the task, because they generally do not allow for localisation without existing infrastructure, do not allow scaling to a large swarm or because they rely on robot behaviour, which introduces a dependency of localisation on a specific swarming algorithm.

Author: M. Liefaard & R.M.A. Bruens & D.R. van Hassel  & S.C. Noorthoek

Contributor:

T.E.P.M.F. Abeel (Coach) & M.K. Verma (Mentor) & C.J.M. Verhoeven (Mentor) & O.W. Visser (Graduation committee member) & H. Wang (Graduation committee member)

Degree granting institution: Delft University of Technology

Programma:  Electrical Engineering

Date: 5 July 2019

Abstract: With the steady increase in space missions, enabled through technological advances and increase of commercialisation within the space flight industry, both more and increasingly complex missions can be designed for space. To this end, the Lunar Zebro project competes within this field through its small lunar rover design, drastically decreasing deployment costs and risk of the mission. The road map of Lunar Zebro aims to have a multitude of rovers deployed on the Moon, being able to complete several tasks like exploring, observing, and mapping. Since this concept of rover cooperation adds a novel level of complexity to the mission, a feasibility study is required to look into the difficulties of navigating the Moon with a larger group of rovers. LunarSim is the software package developed during this project. LunarSim aims to facilitate a simulation environment in which Lunar Zebro rovers and space mission designs can be tested and validated. To legitimise the workings of the simulation, a few scenarios have been developed to test the core functionalities of the software product. These scenarios are based on phases in a practical mission plan that consists out of navigating to and observing a crater location. The scenarios is evaluated through examination of a set of defined fitness criteria. In this report, the reader will find documentation on the development process of LunarSim: the simulation in Unity, the ROS back-end, and the bridge between these two systems. Additionally, the report elaborates how the developed software was used to aid in the feasibility study of LUFAR. First, initial research and requirements are formulated to define the scope of the simulation, after which the software architecture is introduced. Then, the systems implemented for the simulation are explained. Subsequently, the implemented rover behaviour algorithm that was used for testing is explained, with additional resources on how to develop a new custom rover behaviour. After this, an evaluation is given of the simulation based on the initial requirements and research with future research and concluding remarks. At the end of the report, the technical specifications in terms of software architecture, simulation environment, and rover behaviour are defined to give an in-depth view of LunarSim.

Author: den Toom, Matthijs (TU Delft Electrical Engineering, Mathematics and Computer Science)

Contributor: Langendoen, Koen (graduation committee), Verhoeven, Chris (mentor), Nasri Nasrabadi, Mitra (graduation committee)

Degree granting institution: Delft University of Technology

Project: Zebro project

Date: 23 Augustus 2019

Abstract: Automated generation of robot controllers using an Evolutionary Algorithm(EA) has received increasing attention in the last years as it has the potentialfor a reduction in the development time of a robot. Often these EAs generateNeural Networks (NNs) as robot controllers. Using a NN for automaticallygenerating robot controllers has two important downsides: 1.) A human isnot able to fully understand the inner working of a multi-layer NN, and 2.)a NN has only limited abilities to decompose a complex task into sub tasks.Both of these downsides can be addressed by using a State Machine (SM)instead of a NN as robot controller. Therefore, this thesis introduces an EAcalled Evolving State Machines As Controllers (ESMAC). ESMAC generatesSMs instead of NNs. A SM is understandable for humans because ofits modularity and allows for task decomposition by using a state for eachsub task. Furthermore, two extensions of ESMAC are proposed: adaptiveESMAC and selector ESMAC. Adaptive ESMAC aims to automatically determinesthe number of states with which the best tness for a task canbe achieved. Selector ESMAC replaces the transitions that are used in aSM to switch between states with a NN-based switching mechanism. This switching mechanism allows mutations to make more gradual changes to aSM’s behaviours, which improves the performance of the EA. The performance of ESMAC is evaluated on two robotic tasks: come-and-go and phototaxis-with-obstacles. All three variants of ESMAC showequally good performance as a NN-based EA on the evaluated tasks. Thecontrollers generated with standard ESMAC and adaptive ESMAC hardlymake any state transitions and mainly use one state. However, controllers that do use multiple states appear to be more robust to changing scenarios and in noisy environments. Selector ESMAC is able to generate SMs-based controllers that have complementing states and, therefore, shows potentialfor decomposing a task into sub tasks.

Author: Agrawal, Charu (TU Delft Electrical Engineering, Mathematics and Computer Science)

Contributor: Verhoeven, C.J.M. (mentor), Epema, D.H.J. (mentor), Roos, S. (graduation committee), Mastrangeli, M. (graduation committee)

Degree granting institution: Delft University of Technology

Programme: Electrical Engineer | Embedded Systems

Date: 26 Augustus 2019

Abstract: Imagine being lost in a desert with a bunch of friends, all of a sudden. Survival will be difficult. You will have mirages, distrust among friends and no means to leave landmarks on the sand. Unable to locate yourself, you will have no means to contact people with maps. The best you can do in such a situation is to stay together in the vicinity of each other and look for food and water. By staying together, you can see more and decrease faulty data; thereby increasing your survival probability. Robots when left to explore the moon encounter the same issues. They do not have a Geo-Positioning System to locate them nor do they have a map. They have faulty sensor readings and might find it difficult to contact a human operator on earth all the time to solve issues on the moon. Since everything looks the same, there are no landmarks to memorise. As they walk around, their battery will also get exhausted. The more we equip the robot outside earth, chances of faults do not decrease, they increase. Therefore, there is a need to make primitive robots capable of autonomous exploration. We prefer sending more than one robot, inspired by the success of the collective strength of insects in harsh environments. This thesis aims at engineering collective behaviour for a group of robots in such resource-less environments like the moon. We expect this collective behaviour to perform searching in time-critical events like earthquake-stricken areas. The thesis is designed to be implemented on legged robots called Zebros. Using communication, they will collectively perform activities such that they appear as one body of tightly coupled autonomous units. We design three distinct algorithms for such missions. Emergent behaviour is expected from the robots running these algorithms. The swarm should collectively choose the best among the possible options without disintegrating into subgroups. (https://www.youtube.com/watch?v=Yf3ToRk7YHY&feature=youtu.be)

Author: Bongaardt, Laura (TU Delft Mechanical, Maritime and Materials Engineering)

Contributor: Verhoeven, C.J.M. (mentor), Babuska, R. (graduation committee), Della Santina, C. (graduation committee)

Degree granting institution: Delft University of Technology

Programme: Mechanical Engineering | BioMechanical Design

Project: Intelligent Mechanical Systems

Date: 23 april 2021

Abstract: Robots that use legged locomotion have the ability to overcome obstacles and can negotiate a wide range of difficult terrains, such as encountered in outer-space missions. In many practical scenarios however, their applicability is still limited, mainly due to insufficient speed and efficiency. On the other hand, robots that use wheeled locomotion are fast and efficient, but are generally confined to flat or prepared surfaces. A relatively new approach, to use the advantages of both forms, is the combination of walking and driving technology into Hybrid Walker-Wheeler technology. In this research we will explore the feasibility of applying Hybrid Walker-Wheeler technology to the Zesbenige Robot (ZebRo). ZebRo is a small walking robot with six One-Degree-of-Freedom (DoF) legs and walks with an insect-inspired gait. It is being developed with the intention to go on a mission to the moon. The objective in this thesis is to increase the speed and energy efficiency of the ZebRo on flat surfaces, while maintaining its robustness and walking capability on rough terrain. We will set up the criteria for a new design, explore various options and parameters and choose a concept. We will then do a number of simulations to analyse the properties of a wheel and a leg and to apply these in the design. The final prototype consists of a single module with a wheel, a one-DoF leg and a custom-design coupling which switches torque, from the motor, between the wheel-axle and the leg-axle. This prototype was tested and evaluated on its electrical power consumption and the torque and speed transmitted to the leg-axle and wheel-axle. From these results, we were able to draw a number of conclusions and make recommendations for a ZebRo equipped with Hybrid Walker-Wheeler technology.

Author: Rovers, Stijn (TU Delft Aerospace Engineering)

Contributor: Speretta, S. (mentor)

Degree granting institution: Delft University of Technology

Programme: Aerospace Engineering

Date: 30 June 2021

Abstract: The Lunar Zebro is a small six-legged robot. It has the potential to be used in a swarm carrying out objectives like exploring planetary surfaces. A new step towards autonomous navigation is made with the newly developed Obstacle Processing ALgorithm (OPAL) using primarily open-source libraries. This study showed that the initial iteration of OPAL could detect rocks and determine their absolute position to the rover’s low-positioned cameras using a stereo vision system. Obstacles and their relative distances are detected using the disparity map—the amount of shift of pixels in the stereo image pair. When translating the disparity to V-disparity, a histogram of the disparity per row, the ground and the obstacle could be isolated. It took six steps to realise this thesis goal. After setting the requirements, a test model, called Bars, was developed and tested at a location containing a Mars-like environment (Decos). This test model uses, along with Lunar Zebro’s hardware, mostly Commercial Off-The-Shelf products. With the footage, all the different components of OPAL were integrated into one algorithm. Hereafter, a pipeline on a server was created, and multiple test cases were run to establish results. The predetermined requirements of the algorithm were validated using measuring tape measurements and ground-truth bounding boxes tracked by a CSRT-algorithm. Together, Bars and the initial iteration of OPAL prove feasibility and expose opportunities and challenges, which could be a starting point for optimisations or other approaches.

Author: J. van Rijn

Contributor: J.F.L. Goosen & C.J.M. Verhoeven & A.E. Huisjes – Graduation committee member

Degree granting institution: Delft University of Technology

Programme: Department of Precision and Microsystems Engineering | Engineering Mechanics

Date: 25 April 2022

Abstract: Remotely controlled vehicles have gained increased interest and application, like the exploration of inhospitable environments. To this end hexapods with C-shape locomotors are particularly suitable because these vehicles possess both the efficiency of wheels and the climbing capabilities of legged robots. Currently all C-legged hexapods are equipped with the same C-shape tip starting in the center of rotation, yet few to no alternative shapes that could improve the performance have been investigated. The performance is mainly characterized by three measures: traction, climbing and mobility. However, it was also found that no system level performance analysis including constraints exists. In this work a novel method is proposed to describe the system level performance of C-legged hexapods. Using this model, a computer-aided manual optimization of the leg shape is performed, from which it is observed that there is no unique optimal leg shape. The optima depend on the weight factor posed by the designer; but several leg types prove to perform better than the conventional shape. The most prominent trade-off of this hybrid shape is present between climbing and mobility, but this effect can be superseded when the shape is generated conceptually instead of analytically.

Author: Mosab Diab

Contributor: R.T. Rajan & M. Mohammadkarimi &  C.J.M. Verhoeven

Degree granting institution: Delft University of Technology

Programme: Electrical Engineering

Date: 24 Augustus 2022

Abstract:Autonomous agents are the future of many services and industries such as delivery systems, surveillance and monitoring, and search and rescue missions. An important aspect in an autonomous agent is the navigation system it uses to traverse the environment. Not much emphasis has been paid in the past on autonomous agent navigation in cluttered environments. Cluttered and unknown environments such as forests and subaquatic environments need to have autonomous navigation systems developed just for them due to their uncertain and changing nature. Path planning algorithms are used for the navigation of an autonomous agent in an environment. The agent needs to reach a target location while avoiding the obstacles it detects along the path. Such a system is called a Detect and Avoid (DAA) system and there are different implementations for it of which some are explored in this thesis. The Artificial Potential Fields method or APF for short is a method for mobile agent navigation which is based on generating an attractive force on the agent from the target and a repulsive force from the obstacles. This leads to the agent reaching the target while avoiding the obstacles along the way. The Classical APF (CAPF) method works for structured environments well but not for cluttered environments. The CAPF method can be replaced with a modified version where the agent is surrounded by a set of points (called bacteria points) around its current location and the agent moves by selecting a bacteria point as a future location. This method is named the Bacteria APF (BAPF) method. This selection happens through combinatorial optimization based on the potential value of each bacteria point. In this thesis, we propose two distinct contributions to the BAPF method. The first one being the use of an adaptive parameter in the repulsive cost function which is determined through a brute-force search. The second addition is a branching cost function that changes the value of the repulsive potential based on predefined perimeters around each obstacle. We show through simulations on densely and lightly cluttered environments that this Improved BAPF (IBAPF) method significantly improves the performance of the system in terms of the convergence to the target by almost 200% and reduced the time it takes to converge by around 25% as well as maintain the safety of the navigation route by keeping the average distance from obstacles around the same value.

Author: E.D.C. Solot

Contributor:J.F.L. Goosen & C.J.M. Verhoeven & R.A.J. van Ostayen

Degree granting institution: Delft University of Technology

Programme: Department of Precision and Microsystems Engineering | Engineering Mechanics

Date: 12 October 2022

Abstract:

Hexapod robots are becoming increasingly popular for navigating and exploring irregular and inhospitable environments. The Lunar Zebro is such a hexapod robot that has been developed to be the lightest and smallest rover to explore the moon. The purpose of the Lunar Zebro is to navigate the surface of the moon where it will encounter difficult terrains such as regolith (Lunar Soil) and rocks. To date, not much focus has been placed on the design of the Lunar Zebro legs to increase the rover’s trafficability on these terrains. Furthermore, the designs of rover wheels are constantly changing, and new lessons are being learnt from each new mission that the guidelines for designing the wheels and legs of rovers are constantly evolving. Using a Biomimicry design framework, the legs of the Lunar Zebro were redesigned using strategies adopted by animals in nature to improve the trafficability of the legs on granular and rocky terrains. Several concepts were created and narrowed down to four final designs (Hair, Web, Paddle and Claw Legs) that were further developed and manufactured. In addition to this, the original leg design and a flat leg with no grousers were developed for testing.

Several different single-leg tests were performed on the legs to measure their sinkage, thrust, rolling resistance and drawbar pull on regolith and rocky surfaces. The results showed that hair has the potential to reduce sinkage on regolith. However, the results from the single-leg tests on regolith also indicated that there is not much difference in the drawbar pull performance of the different legs no matter what features were included on the bottom of the leg or if the leg had grousers or not. In contrast, the results of the experiments performed on rocky surfaces showed that legs with claw-like grousers performed the best.

From there a hybrid leg was designed using the finding of the single-leg tests and this leg was tested on a basic Lunar Zebro prototype against the original Lunar Zebro leg design to determine if the hybrid improves the trafficability of the rover on both regolith and rocky terrains. These tests included testing the drawbar pull of the rover at 100 % slip and measuring the distance travelled by the rover over five steps. The results showed that on regolith terrain, the design of the leg does not have a big impact on the performance of the rover. However, the results showed that on rocky terrain the rover with hybrid legs travelled roughly 10 % further over five steps and had a drawbar pull roughly 10 % larger than the rover with original legs.

Author: A. Shanbhag

Contributor: A. Menicucci & E.K.A. Gill &  C.J.M. Verhoeven

Degree granting institution: Delft University of Technology

Programme: Aerospace Engineering

Date: 1 November 2022

Abstract: A miniaturized instrument was developed to enable in-situ measurements of the radiation environment at the Moon. The instrument is designated to function as the science payload for the first mission of the Lunar Zebro nano-rover. Characterization and testing of the Floating Gate Dosimeter (FGDOS) was advanced with an emphasis on its utilization as the core detector for this payload. A prototype of the Radiation Payload was designed, produced and tested. Radiation environment prediction and analysis was performed for various mission phases using SPENVIS and OLTARIS. A radiation transport model of the payload was prepared, as a foundation for more extensive simulations in the future.

This thesis highlights the need for further research and development of the FGDOS technology, including experimental mapping of the complete envelope of FGDOS sensitivity based on expected mission radiation environments. Additional noise reduction measures and thermal characterization at mission conditions are needed to iterate and improve the payload design such that it can be made flight-worthy.

Author: Jesús Manuel Muñoz Tejeda & Pablo Fajardo & C Verhoeven & M. K. Verma

Abstract: Lunar Zebro’s mission is heading the race for deploying the world’s smallest and lightest swarm of nanorovers on the surface of Moon. The concept validation of a single nanorover is of crucial importance, as it will be the launching pad for deploying a swarm of those nanorovers thereafter. Then, they will get connected in a network, acting as a single device and performing scientific missions analyzing data from remote points on the Moon’s surface. In the current study, the complete set of thermo-mechanical-radiation analyses for Lunar Zebro nanorovers are carried out. These range from the Ground Segment to the Moon environment, taking also into account the extreme mechanical and thermal environment at launch-transit conditions when the nanorover is attached to the lander. An innovative ray tracing method to evaluate the effect of the thermal environment on the Lunar Zebro nanorovers is explained in this paper. Material choices, structural design, and mechanical/thermal strategies for the nanorover to overcome the launch, space and Moon’s conditions are shown. The different analyses methods used, expected loads and results obtained should serve as a baseline for evaluating the behaviour of other small devices attached to a lander when aiming for any space mission. More specifically, for those aiming to go to the Moon, the environmental and mechanical expectations here can also be implemented. The ultimate outcome of the paper is the environmental survivability assurance from an analytical perspective of these nanorovers when being sent to the Moon. The validation of the survivability of a single nanorover will be a breakthrough in the space swarm robotics’ field, resulting in the successful performance of the lightest swarm of nanorovers ever deployed on the Moon’s surface.

Author: L.I.A. Gelling

Contributor: R.T. Rajan & C.J.M. Verhoeven

Degree granting institution: Delft University of Technology

Programme: Electrical Engineering | Embedded Systems

Date: 31 Januari 2023

Abstract: The unique six-legged swarming rover Lunar Zebro is designed and produced by students from the Delft University of Technology. The objective of the rover is to accomplish an autonomous mission on the Lunar surface by 2024. This thesis evaluates a path planning algorithm that is designed for autonomous navigation in the Lunar environment. The thesis studies existing path planning algorithms and determines the essential functionalities of the algorithm and the unique requirements of Lunar Zebro. It is found that an Artificial Potential Field based path planning algorithm accommodates the determined needs and requirements.
With the help of the Artificial Potential Field path planning algorithm and the unique requirements, a vector field based algorithm is developed. The algorithm uses an attractive vector field to attract the rover to the determined target. Meanwhile, obstacles or other obstructions are denoted by a repulsive rotational vector field around the edge of the obstacles. This rotational repulsive force ensures obstacle avoidance and prevention of the local minimum trap, which often occurs in Artificial Potential Field path planning. Improvements are suggested to increase reachability and decrease path length and planning time of the rotational vector field algorithm. In the Python developed simulation, the improved algorithm accomplishes a 62% reduction in planning time compared with the original Artificial Potential Field algorithm and achieves similar path length results. Moreover, the proposed algorithm has a reachability of 90% where the Artificial Potential Field algorithm just reaches a success rate of 55%.
The thesis concludes with the future work recommendations for a low level implementation in C or either C++ to facilitate the deployment in a microcontroller.

Author: J.N. du Plessis & M.G.E. Roos

Contributor: C.J.M. Verhoeven

Degree granting institution: Delft University of Technology

Faculty: Electrical Engineering, Mathematics
and Computer Science

Date:  June 2023

Abstract: This thesis aims to solve the problem of designing the hardware for a wireless charging system to be used for keeping an autonomous robot swarm alive. Previous designs available to us lacked essential safety features and were very specific in their application. Current wireless charging specifications are also not sufficient to cater to the needs of these systems. Using a detailed analysis and clear requirements, this thesis describes the process of developing the hardware for such a system with flexibility and safety in mind

Author: J.J. van Veen  & J.J.C. Goudzwaard

Contributor: C.J.M. Verhoeven & A.J. van der Veen & K.M. Dowling & S. Feld

Degree granting institution: Delft University of Technology

Faculty: Electrical Engineering, Mathematics
and Computer Science

Date:  June 2023

Abstract:

The goal of this thesis is to develop a ROS package that facilitates the control and navigation of a Duckiebot robot. With the rise of robot swarms the need for autonomous charging system for robots is increasing. An implementation for decentralised autonomous behaviour for a Duckiebot for a wireless charging system in a Duckietown environment is discussed. The devised system is divided among three different modules and is implemented in ROS:
• An image recognition module;
• A navigation module;
• A motion control module;
The image recognition module uses linear image processing techniques and YOLO object detection in order to detect objects in images from the robots front facing camera. It detects traffic lights and road markings in order to tell the robot where to go.

The navigation module uses odometry to keep track of the robots current position. The odometry is reset in order to maintain accuracy. When the battery of the robot reaches a certain point the robot will decide to
charge. It will then initiate path finding using Lee’s algorithm in order to find a path to a charging park.

Finally the motion control processes all the information in order to drive the wheels of the robot.
The system is thought to be able to navigate to a charging station, charge and then leave the charging station using the designed ROS package.

Author: T.H. Appelman & C. Bruinsma & A. Ouaissa

Contributor: C.J.M. Verhoeven & M. Spirito & M. Ghaffarian Niasar

Degree granting institution: Delft University of Technology

Faculty: Electrical Engineering, Mathematics
and Computer Science

Date:  June 2023

Abstract: Lunar dust presents a serious problem for future lunar rovers. Due to the charged nature of this fine dust, it tends to stick to sensitive elements like solar panels. It is clear that a system needs to be implemented in order to remove lunar dust to keep the output power of the solar panel at a satisfactory level. This paper develops the proof of concept electronics for a method sometimes called an electrodynamic screen, that uses electrostatic fields to sweep away the dust adhered to the surface of the solar panel. The electronics for this system needs to produce a high voltage three phase pulse wave in order to drive the electrodes placed on top of the solar panel. The design of the electrodes themselves are not part of this thesis, but it is the main subject of the companion thesis produced by other members of our group.

Author: T.O. Geerling & M. Mihankhah & T.B. Plantfeber

Contributor: C.J.M. Verhoeven & F.J.P. van Mourik

Degree granting institution: Delft University of Technology

Programme: Electrical Engineering

Date: 30 June 2023

Abstract: One of the major challenges faced by future robotic and human missions to Mars and the Moon is the presence of atmospheric dust. The Lunar Zebro rover which is intended to walk on the Moon is powered by solar panel. Due to its surrounding terrain, which mostly consists of small particles, the rover may be a potential target for dust accumulation, which reduces its output power. For the longevity of any space mission, it is important to have a long-lasting source of energy. That is why during this project, an Electrodynamic screen is constructed which could remove dust from a 100 x 100 mm area without containing moving parts. One subgroup concentrated on building the electronics necessary to create a high voltage (~1.6kV) three-phase drive signal, the other group focused on the electrodes of the system and described the effects of an electric field on dielectric particles. These are mostly found on the Moon. Different electrode architectures are proposed, but the zigzag architecture was found to be the best suited for a possible dust removal system. Furthermore, the higher voltage applied to the electrodes, the greater the forces exerted on the particles are. Further research should be conducted for any possible implementation. It is recommended to also read the other thesis.

Author: C.M. Sinck

Contributor: J.F.L. Goosen

Degree granting institution: Delft University of Technology

Programme: Department of Precision and Microsystems Engineering | Engineering Mechanics

Date: 23 Augustus 2023

Abstract: A prototype lunar rover is in development by students of the TU Delft since 2017. It is a nanorover based on the terrestrial ZeBRo design, now named the Lunar Zebro. The Lunar Zebro is a prototype design as a proof of concept for nanorover capabilities. With a chassis of 200 by 140 by 60 millimeters, fitting on a sheet of A5 paper, the Lunar Zebro is intended to be the smallest and lightest autonomous rover on the Moon to date. The objective is to traverse a distance of 200 meters during a lunar day, surviving the harsh environment and strong solar radiation. Due to the limited time budget there is little refinement in the structural design. The resulting functional but heavy design leaves many opportunities for optimization.
While there are many examples of successful planetary rover missions, little is published concerning the design of the structures. This report contains further analysis of the design of satellite structures. The various structure types and design requirements highlight the importance of thermal transport and resistance to mechanical launch loads. Compared to the deployed planetary rovers, the Lunar Zebro is unique in many ways. The small size facilitates production of the current monolithic chassis which is ideal in its thermal conduction and environmental sealing properties. However with a constant plate thickness and no reinforcing substructure, the structure is not an efficient loadbearing design. Due to the many requirements and unique mission profile of the Lunar Zebro, there is no clear method by which to optimise the structure.
To better understand the current structure and reduce the mass, a case study is performed with Finite Element Methods. After validating a modelling approach for thin plate reinforcement, a simplified chassis structure is generated. Maintaining the essential configuration of the chassis and connected components, the response to the static launch load of 10G is analysed. Several methods for rib placement design are tested while reducing the plate thickness. Buckling behaviour and CNC production limitations are accounted for in this approach. To minimally affect the other design requirements, the stiffness of the structure is maintained. While the placement of ribs is sensitive to the vicinity of connected components, equally stiff designs can be obtained with reinforcement grids. Reducing the plate thickness by 66.6%, a mass reduction in the order of 50% can be achieved without sacrificing stiffness. However, local adjustments are required to prevent plastic deformation in high stress areas.
From there the analysis and design of reinforcement grids is investigated further. Grids are often seen in aerospace applications due to the convenient geometries for CNC production, light weight and predicable orthotropic or isotropic behaviour. A smeared stiffness approach is investigated that relates the rib and plate interaction to composite plate theory. Applying this analysis method provides beneficial insight in the parameters and related stiffness behaviour of a grid reinforced plate. By modelling three common grid sections on a hypothetical plate design scenario with varying boundary conditions, the important criteria for the selection and design of a reinforcement grid are provided.

Author: Martijn Hubers, Mladen Gagic, Aditya Shekhar

Date: 16 November 2023

Abstract:The small, light-weight and modular Lunar rover must survive several earth days in harsh environment after its moon landing. Its power electronic system with integrated solar generation needs power for its mission and also to stay warm in very cold temperatures of the moon. This paper presents the design of the power electronic system of the Lunar Zebro rover. Two topologies are compared that result from using a 12 V bus and 24 V bus. The design of the DC/DC converters required is presented for CCM and DCM operation. The losses in the DC/DC converters operating in CCM and DCM are calculated for the two bus voltages to determine the mode of operation and bus voltage that results in the highest efficiency. Further, the average power loss during operation of the rover is estimated for both bus voltages. Operating the DC/DC converters in CCM using a 12 V bus results in the lowest losses.

Author: S.J. van Egmond

Contributor: J.F.L. Goosen & F.G.J. Broeren

P. Breedveld

Degree granting institution: Delft University of Technology

Programme: Department of Precision and Microsystems Engineering | Engineering Mechanics

Date: 16 November 2023

Abstract: The Lunar Zebro is a small moon rover that needs an advanced chassis to endure the harsh environment that the moon brings. To arrive at a solution for such a frame or chassis creativity and hard work are necessary. Whereas hard work is a given, creativity is not and it may need a helping hand. Design synthesis methods, of which brainstorming is a basic example, aid engineers and designers with reaching better solutions. Currently, however, which method works best for a given scenario is unknown. The purpose of this research is to determine which synthesis method works best for concept generation, with the focus lying on generating innovative solutions for frame design. A meta-method is created to evaluate the performance of different synthesis methods when applied to design cases. This meta-method consists of executing fifty case-method combinations, built up from pairing ten design synthesis methods with five design cases, which are focused on frame design primarily. The combinations are then evaluated using a self-made rubric. In the end, it became apparent that different methods apply well at different stages of the design process and at different system levels. Some work well to orient, understand the supersystem and therefore have an positive yet indirect influence on the final outcome. Some work well to generate concepts, bring new ideas at system level. Others apply well after a concept is already generated, only being useful to improve subsystems.

Author: M.D. Hubers

Contributor: A. Shekhar & Mladen Gagic – Mentor & P. Bauer &  C.J.M. Verhoeven

Degree granting institution: Delft University of Technology

Faculty: Electrical Engineering,
Mathematics and Computer Science | Electrical Engineering

Date: 19 December 2023

Abstract:

The small and lightweight Lunar Zebro rover must survive in the harsh lunar environment for several Earth days following its moon landing. The mission of the rover is to map the radiation environment on the moon. The success of the entire mission depends on the Power Electronic System (PES), which supplies power to all subsystems and charges the batteries using solar panels. The current PES of the Lunar Zebro rover does not comply with all mission-specific requirements and does not perform satisfactorily when integrated into the rover. Therefore, the need for a reliable PES that conforms to all requirements arises for the Lunar Zebro rover.

In this research, the design and implementation of an efficient, compact, and redundant PES for the Lunar Zebro rover is developed. First, the optimal Direct Current (DC) bus is designed to obtain a system with the highest efficiency. This is done by modelling the efficiency of the DC/DC converters for different bus voltages and estimating the overall losses in these converters during the deployment of the rover. Moreover, the effect of the bus voltage on the size of the passive components is investigated, and the bus voltage resulting in the most compact system is obtained. It is found that a 12 V bus results in the most efficient and compact system. No additional converter is required that regulates the 12 V output, and the inductance required for each converter is decreased compared to higher bus voltages.

Besides the DC bus design, redundancy methods are compared to obtain the best tradeoff between redundancy and footprint added. The two-phase interleaved converter was found to have only an 8.59% increase in footprint compared to single-phase converters, while failure in a switch, diode, input capacitor, and output capacitor are accounted for in each converter. Finally, the mode of operation that results in the highest efficiency is obtained by designing each converter and modelling the corresponding losses for Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) operation. For both the single-phase and two-phase interleaved converters hold that operating in CCM results in a significant increase in efficiency compared to DCM operation. Moreover, the PES utilising two-phase interleaved converters is more efficient during rover operation than the single-phase counterpart. However, charging is less efficient than for the single-phase counterpart. Simulink and LTspice simulations have been carried out to verify the operation of each converter. Finally, experiments on a functional prototype are carried out to provide experimental validation of the design.

Author: Thijs Bolscher

Contributor:

A. Menicucci & David Rijlaarsdam & J. Guo  & G. Gaydadjiev

Degree granting institution: Delft University of Technology

Faculty:  Aerospace Engineering

Date: Januari 2024

Abstract: As the Moon reemerges as a renewed fronteer in space exploration, the Lunar Zebro project proposes to deploy a swarm of miniature rovers for efficient lunar surface exploration. One of their goals is to leverage recent advancements in deep learning and AI-accelerating hardware, in conjunction with Commercial Off-The-Shelf technologies and the NewSpace movement, to enhance the autonomous capabilities of these nano-rovers. This research focuses on integrating AI-accelerating hardware within the stringent Size, Weight, and Power (SWaP) constraints of these lunar rovers. It evaluates the suitability of various hardware configurations. A Convolutional Neural Network for hazard detection was trained and tested on different devices and scenarios. Finally, the operational cycle of the rover was simulated and the constrained resources were tracked for the different design options.

 zAuthor: A.S. Koshy

Contributor: R.T. Rajan

Degree granting institution: Delft University of Technology

Departement: Signal Processing Systems Group

Date: 8 May 2024

Abstract: Autonomous navigation is a critical aspect of robotic systems, particularly in hostile and uncertain environments, and robot localization is central to navigation. Robot localization establishes its position within its surroundings. This thesis addresses the challenge of robot localization, focusing on a lunar-like environment with constraints such as limited computational resources and the use of non-visual based sensors. In this thesis, three sensors — wheel encoders (WE), Sun sensor (SS), and inertial measurement unit (IMU) — are employed for localization. Each sensor contributes distinct information regarding position and orientation. However, individual sensor measurements suffer from inherent inaccuracies and errors, especially the IMU’s reliance on integration over time, leading to significant drift. To mitigate these challenges, three fusion methods are explored: sensor selection based on predefined thresholds, Kalman filtering, and weighted fusion. Results indi- cate substantial improvements in localization accuracy compared to individual sensor measurements. The weighted fusion method, in particular, demonstrates superior per- formance by assigning appropriate importance, according to their accuracy, to each sensor’s information, resulting in significantly reduced positioning errors. The maxi- mum localization error using this method is 92m, which is smaller than reported in the literature. Further, the maximum localization percentage error over 65m is around 8%, which is comparable to the literature with visual sensors. The weighted fusion method introduces only a marginal increase in the computational complexity. Thus, this method stands out for its simplicity and delivers results superior to those documented in existing literature for non-visual sensors. Despite promising results, the research is met with certain hurdles, notably the avail- ability and consistency of datasets. The reliance on existing datasets, such as the Devon Island Rover dataset, highlights the need for standardized and comprehensive datasets for thorough testing and validation. Calibration inconsistencies and verification issues further underscore the complexity of real-world implementation. Nevertheless, the findings of this thesis offer insights into the integration of multiple sensors for enhanced localization in lunar-like environments. By leveraging complementary sensor data and employing efficient fusion techniques, the proposed approach enables more accurate and reliable navigation of lunar micro rovers, thus advancing the capabilities of autonomous robotic systems for future lunar exploration missions.

Author: S.J.H. Ramhit & B. Goethals

Contributor: C.J.M. Verhoeven & S. Feld & D. Cavallo

Degree granting institution: Delft University of Technology

Faculty: Faculty of Electrical Engineering

Date: June 2024

Abstract: This thesis details the design and development of the Power System for the Rover Deployment System. This power system delivers and manages the necessary power required by the entire Rover Deployment System. The RDS is responsible for ensuring the rover’s survival inside the transportation pod during transit. It also handles releasing the rover, which a mechanical mechanism will lower onto the lunar surface. The goal of Lunar Zebro is to send a nanosatellite to the moon for lunar surface exploration and radiation measurements. The power system was designed to power the MCU and transceivers at 3.3V, to provide power for rover charging at 12V, and to charge a capacitor bank used to provide the necessary actuation power to the NEAs. An electrically triggered umbilical release mechanism, unfortunately, could not be implemented due to a lack of available data. The circuit for this system was created, simulated, and added to the PCB design of the RDS. The simulations of the circuit behaved desirably. Due to the lead time on orders, the PCB has unfortunately not been received yet. Because of this, the entire power system has unfortunately not been tested yet.

Author: H. Vanhuynegem & D.Y. Aris

Contributor: C.J.M. Verhoeven

Degree granting institution: Delft University of Technology

Faculty: Faculty of Electrical Engineering

Date: June 2024

Abstract: The Rover Deployment Software System (RDSS) is a critical component designed to ensure the successful deployment of the Lunar Zebro rover onto the lunar surface. This thesis presents the design, implementation, and testing of the RDSS, which consists of three primary subsystems: a communication system between the lander and the RDSS, an electronic control system, and an integration with an existing rover communication system. Moreover, the existing rover communication system will not be covered in this thesis due to the implementation being done by the Lunar Zebro team in the future. The RDSS is tasked with managing the deployment sequence, providing power during transit, and facilitating communication between the rover and the lander. Key challenges addressed include handling the harsh lunar environment, ensuring reliable communication, and adhering to strict weight constraints. Extensive testing, including unit, integration, system, and performance tests, validated the system’s robustness and reliability. The insights and methodologies developed are intended to support the Lunar Zebro mission and inform future projects involving space deployment systems.

Author: N. Kant & T.J. Velzel

Contributor: C.J.M. Verhoeven & A.J.M. Montagne & H. Bastawrous & D. Cavallo

Degree granting institution: Delft University of Technology

Faculty: Electrical Engineering, Mathematics and Computer Science

Date: June 2024

Abstract: The Rover Deployment Software System (RDSS) is a critical component designed to ensure the successful deployment of the Lunar Zebro rover onto the lunar surface. This thesis presents the design, implementation, and testing of the RDSS, which consists of three primary subsystems: a communication system between the lander and the RDSS, an electronic control system, and an integration with an existing rover communication system. Moreover, the existing rover communication system will not be covered in this thesis due to the implementation being done by the Lunar Zebro team in the future. The RDSS is tasked with managing the deployment sequence, providing power during transit, and facilitating communication between the rover and the lander. Key challenges addressed include handling the harsh lunar environment, ensuring reliable communication, and adhering to strict weight constraints. Extensive testing, including unit, integration, system, and performance tests, validated the system’s robustness and reliability. The insights and methodologies developed are intended to support the Lunar Zebro mission and inform future projects involving space deployment systems.

Author: William De Meyere & Abhimanyu Shanbhag & Alessandra Menicucci

Date: Augustus 2024

Abstract: Autonomous navigation is a critical aspect of robotic systems, particularly in hostile and uncertain environments, and robot localization is central to navigation. Robot localization establishes its position within its surroundings. This thesis addresses the challenge of robot localization, focusing on a lunar-like environment with constraints such as limited computational resources and the use of non-visual based sensors. In this thesis, three sensors — wheel encoders (WE), Sun sensor (SS), and inertial measurement unit (IMU) — are employed for localization. Each sensor contributes distinct information regarding position and orientation. However, individual sensor measurements suffer from inherent inaccuracies and errors, especially the IMU’s reliance on integration over time, leading to significant drift. To mitigate these challenges, three fusion methods are explored: sensor selection based on predefined thresholds, Kalman filtering, and weighted fusion. Results indi- cate substantial improvements in localization accuracy compared to individual sensor measurements. The weighted fusion method, in particular, demonstrates superior per- formance by assigning appropriate importance, according to their accuracy, to each sensor’s information, resulting in significantly reduced positioning errors. The maxi- mum localization error using this method is 92m, which is smaller than reported in the literature. Further, the maximum localization percentage error over 65m is around 8%, which is comparable to the literature with visual sensors. The weighted fusion method introduces only a marginal increase in the computational complexity. Thus, this method stands out for its simplicity and delivers results superior to those documented in existing literature for non-visual sensors. Despite promising results, the research is met with certain hurdles, notably the avail- ability and consistency of datasets. The reliance on existing datasets, such as the Devon Island Rover dataset, highlights the need for standardized and comprehensive datasets for thorough testing and validation. Calibration inconsistencies and verification issues further underscore the complexity of real-world implementation. Nevertheless, the findings of this thesis offer insights into the integration of multiple sensors for enhanced localization in lunar-like environments. By leveraging complementary sensor data and employing efficient fusion techniques, the proposed approach enables more accurate and reliable navigation of lunar micro rovers, thus advancing the capabilities of autonomous robotic systems for future lunar exploration missions.

Author: Thomas Manteaux , David Rodriguez-Martinez, Raj Thilak Rajan

Date: 27 September 2024

Abstract: Efficient path planning is key for safe autonomous navigation over complex and unknown terrains. Lunar Zebro (LZ), a project of the Delft University of Technology, aims to deploy a compact rover, no larger than an A4 sheet of paper and weighing not more than 3 kilograms. In this work, we introduce a Robust Artificial Potential Field (RAPF) algorithm, a new path-planning algorithm for reliable local navigation solution for lunar microrovers. RAPF leverages and improves state of the art Artificial Potential Field (APF)-based methods by incorporating the position of the robot in the generation of bacteria points and considering local minima as regions to avoid. We perform both simulations and on field experiments to validate the performance of RAPF, which outperforms state-of-the-art APF-based algorithms by over 15% in reachability within a similar or shorter planning time. The improvements resulted in a 200% higher success rate and 50% lower computing time compared to the conventional APF algorithm. Near-optimal paths are computed in real-time with limited available processing power. The bacterial approach of the RAPF algorithm proves faster to execute and smaller to store than path planning algorithms used in existing planetary rovers, showcasing its potential for reliable lunar exploration with computationally constrained and energy constrained robotic systems.

 Author: I. Hassan

Contributor: R.T. Rajan & R. Sabzevari

Degree granting institution: Delft University of Technology

Departement: Signal Processing Systems Group | Electrical Engineering

Date: 18 December 2024

Abstract: This thesis presents an approach to monocular depth estimation for Unmanned Aerial Vehicles (UAVs). Monocular depth estimation is a critical perception task for UAVs, enabling them to infer depth information from visual data without relying on heavy or power-consuming sensors such as LiDAR or stereo cameras. Given the operational constraints of UAVs, such as limited payload and energy resources, robust and efficient depth estimation methods are required to facilitate safe navigation and environmental interaction. The proposed methodology in this thesis integrates visual data from a monocular camera with inertial measurements from an Inertial Measurement Unit (IMU) sensor. This combination aims to address challenges such as scale ambiguity in the depth estimates and inaccuracies in dynamic environments that are common in aerial operations. The integration of IMU data with a differentiable camera-centric Extended Kalman Filter (EKF) allows for better ego-motion estimation, effectively calibrating the visual information with drone dynamics. The method further incorporates depth map frame prediction, leveraging initial depth estimates along with temporal dynamics to predict future depth maps. This predictive capability improves efficiency by reducing the need for full depth estimation in every frame, allowing robotic agents to anticipate environmental changes. The evaluation on simulated and real-world datasets shows that while the algorithm performs well over short forecast horizons, accumulating errors from IMU data and the assumption of a static environment limit its long-term accuracy. The future depth map prediction algorithm reduced the need for DynaDepth from 10 runs per second to 2, and on the Mid-Air dataset, from 25 to 5. Additionally, this study provides a foundation for future work, including the integration of an object-oriented frame prediction algorithm.

Author: S. Broere

Contributor: A.Meniccuci &  J. Plomp  & D. Lathouwers

Degree granting institution: Delft University of Technology

Departement: Applied Physics | Physics of instrumentation

Date: 14 march 2025

Abstract: As humanity prepares to return to the Moon, understanding its complex radiation environment becomes increasingly critical. Radiation hardness assurance is essential to ensure that the payload remains operational and reliable under prolonged exposure to harsh space conditions. This thesis investigates the performance of the Floating Gate Dosimeter (FGDOS) as part of the Lunar Zebro nano-rover payload developed at TU Delft. The sensor’s response was evaluated through a series of irradiation campaigns: low-dose gamma radiation at the Reactor Institute Delft (RID), proton irradiation at HollandPTC, and mixed-field exposure at CERN’s CHARM facility. While the FGDOS demonstrated linear dose-response behavior and potential for spaceborne dosimetry, several limitations were identified, including reduced sensitivity, temperature dependence, and a firmware-related recharging issue.

A preliminary investigation into the use of a boron carbide layer showed a measurable increase in neutron sensitivity, suggesting its relevance for shielding strategies in mixed-field environments. Although the current payload is not yet flight-ready, it provides a robust foundation for further development. Future work should focus on high-flux gamma testing and refinement of both hardware and firmware to improve measurement reliability and system resilience in the lunar radiation environment.

Author: A.M. Rozendaal

Contributor: C.J.M. Verhoeven  & J.H. Boyle & M.C. Rozendaal

Degree granting institution: Delft University of Technology

Date: 25 June 2025

Abstract: This thesis asks whether spiking neural networks (SNNs) and neuromorphic computing constitute a promising alternative to present-day artificial neural networks (ANNs) for autonomous space missions. Focusing on a resource- and power-constrained 1U CubeSat transiting the Van Allen radiation belts, TIENOS is a toolchain that injects radiation-inspired perturbations into trained models and records the layer-specific reactions.

The framework systematically emulates dominant soft-error mechanisms by applying (i) bit-flip faults representative of single-event upsets, (ii) additive Gaussian noise as a proxy for thermal/analog variability, and (iii) dropout-style masking to approximate transient loss or zeroing of activations. Using MNIST (frame-based) and N-MNIST (event-based) benchmarks, we compare LeNet-5–style convolutional neural networks and size-matched multilayer perceptrons with their spiking counterparts to establish an ideal software training baseline. The tool produces per-layer vulnerability profiles and robustness heatmaps across a broad range of perturbation rates, quantifies activity sparsity in SNNs, and can be used to evaluate noise-aware retraining to improve robustness without any overhead, with a path towards on-chip protections such as selective redundancy (such as triple-modular redundancy for neuron parameters), ECC and scrubbing.

Results show that fragility concentrates in a limited subset of layers depending on the fault mechanism, enabling targeted hardening with modest cost. It also indicates that noise-aware retraining improves tolerance without prohibitive accuracy loss and that SNN sparsity yields favourable energy–robustness trade-offs for bursty, event-driven sensing typical of small spacecraft. In this study, the noise-aware learned weights used for inference by the two-tinyODIN setup deliver a 15% higher accuracy for up to 2% of bit-flips in the system. Hybrid ANN–SNN pipelines could further enlarge this envelope by deploying spiking computation where sparsity is highest while retaining dense processing elsewhere, acknowledging that the scalability and baseline power of current neuromorphic platforms remain practical constraints. Overall, the methodology translates environmental assumptions for a 1U CubeSat in the Van Allen belts into actionable, layer-level design rules, providing a principled basis for space-grade, energy-efficient digital SNN accelerators and an open, extensible tool to localise and mitigate radiation-induced vulnerabilities.

Author: S.X. Bloem

Contributor:  J.F.L. Goosen

Degree granting institution: Delft University of Technology

Date: 22 August 2025

Abstract: Extra-terrestrial rovers play a vital role in the acquisition of scientific data on celestial bodies, offering a reduced risk and cost compared to human exploration. In pursuit of mapping the lunar surface, a swarm of nano-rovers can collectively form a network and cover extensive areas. The Lunar Zebro, a hexapod nano-rover, employs an innovative C-shaped leg module that combines the efficiency of a wheel with the stability and climbing capability of a leg. The current C-shaped leg module features a fully rigid design, for which tractive performance could be improved by increasing the soil contact area. Due to the extreme thermal environment on the Moon, this improvement must be achieved using compliant mechanisms and space-graded material. Consequently, the research goal is to design a compliant leg module to enhance the tractive performance of the Lunar Zebro on lunar terrain, employing an analytical optimisation model that combines compliant system behaviour with the mechanics of leg-soil interaction.
The design process employs a morphological analysis along with the ACRREx method, in which different subproblem solutions are combined into multiple concepts. The performance of these concepts is evaluated against selection criteria, leading to the creation of the final concept by integrating the design features associated with high criteria performance. The final concept is translated into an analytical model utilising Castigliano’s theorem to describe the compliant behaviour and Wong’s terramechanics theorem for deformable wheels to describe the leg-soil interaction. A set of design variables impacting the system’s compliant behaviour is defined, for which the tractive performance is optimised while confined by constraints that ensure reliability and durability across various movements and scenarios. The optimisation process is conducted using Sequential Quadratic Programming, due to the non-linearity of the objective function and constraints. An optimal set of design variables is identified for both the middle and outer legs, resulting in not only a significant enhancement of tractive performance but also an increase in tractive efficiency and reduction of leg sinkage. Although concerns are raised about contact surface wear at the optimal set of design variables, a minimal amount of compliance, while staying in the feasible region of the design variables, enhances the tractive performance of the compliant leg compared to the original rigid leg. A final leg design is presented that incorporates modifications informed by research findings.

Author: P. Garg

Contributor: J.F.L. Goosen

Degree granting institution: Delft University of Technology

Date: 5 September 2025

Abstract: This thesis focuses on the use of Carbon Fiber Reinforced Polymer (CFRP) to optimize the Lunar Zebro (a six legged nano rover) chassis for lightweight yet robust lunar exploration. Using the Solid Mechanics and Layered Shell module in COMSOL Multiphysics, CFRP and Aluminium designs were compared under launch-equivalent loading, with performance evaluated through displacement, stiffness, and failure criteria. From plate-level studies to complete chassis simulations the work progresses and further explores new structural configurations, reinforcements and geometric stiffeners to enhance mass efficiency. Compared to Aluminium, the final design achieves over 83% mass reduction while maintaining high stiffness and dynamic safety. The study demonstrates how composite modeling and geometric redesign together enable efficient and resilient nano-rover structures for future lunar missions.

Author: Ahmed Hegazy &Marco Rossoni & Marina Carulli

Date: October 2025

Abstract:The future of space exploration relies not only on technological advancements but also on public awareness and policy support. Sustaining long-term investments in lunar and planetary missions requires effectively engaging both the next generation and key decision-makers. However, traditional science communication methods often fail to reach audiences beyond academic and professional circles, limiting public engagement. Virtual Reality and Serious Games offer interactive and immersive experiences that make complex scientific concepts more accessible to non-experts, fostering broader support for space exploration initiatives. This study evaluates the effectiveness of a Virtual Reality Serious Game designed to simulate the Lunar Zebro rover navigating the Moon’s surface. The game aims to enhance engagement, simplify scientific concepts, and shape public perception of space missions. Through iterative development and user testing, the study examines the balance between education and entertainment. Preliminary findings indicate that while the game successfully engages users and communicates mission objectives, it is primarily perceived as an interactive experience rather than a standalone educational tool. These insights highlight the potential of VR Serious Games in science communication and their role in promoting future space exploration initiatives.

Author: S. Okade

Contributor: R.T. Rajan & C. Frenkel & F. Fioranelli

Degree granting institution: Delft University of Technology

Departement: Signal Processing Systems Group | Electrical Engineering

Date:

Abstract: This thesis asks whether spiking neural networks (SNNs) and neuromorphic computing constitute a promising alternative to present-day artificial neural networks (ANNs) for autonomous space missions. Focusing on a resource- and power-constrained 1U CubeSat transiting the Van Allen radiation belts, TIENOS is a toolchain that injects radiation-inspired perturbations into trained models and records the layer-specific reactions.

The framework systematically emulates dominant soft-error mechanisms by applying (i) bit-flip faults representative of single-event upsets, (ii) additive Gaussian noise as a proxy for thermal/analog variability, and (iii) dropout-style masking to approximate transient loss or zeroing of activations. Using MNIST (frame-based) and N-MNIST (event-based) benchmarks, we compare LeNet-5–style convolutional neural networks and size-matched multilayer perceptrons with their spiking counterparts to establish an ideal software training baseline. The tool produces per-layer vulnerability profiles and robustness heatmaps across a broad range of perturbation rates, quantifies activity sparsity in SNNs, and can be used to evaluate noise-aware retraining to improve robustness without any overhead, with a path towards on-chip protections such as selective redundancy (such as triple-modular redundancy for neuron parameters), ECC and scrubbing.

Results show that fragility concentrates in a limited subset of layers depending on the fault mechanism, enabling targeted hardening with modest cost. It also indicates that noise-aware retraining improves tolerance without prohibitive accuracy loss and that SNN sparsity yields favourable energy–robustness trade-offs for bursty, event-driven sensing typical of small spacecraft. In this study, the noise-aware learned weights used for inference by the two-tinyODIN setup deliver a 15% higher accuracy for up to 2% of bit-flips in the system. Hybrid ANN–SNN pipelines could further enlarge this envelope by deploying spiking computation where sparsity is highest while retaining dense processing elsewhere, acknowledging that the scalability and baseline power of current neuromorphic platforms remain practical constraints. Overall, the methodology translates environmental assumptions for a 1U CubeSat in the Van Allen belts into actionable, layer-level design rules, providing a principled basis for space-grade, energy-efficient digital SNN accelerators and an open, extensible tool to localise and mitigate radiation-induced vulnerabilities.

Author: M.Minten

Contributor:

C.J.M. Verhoeven, G. Gaydadjiev, A. Noroozi 

Degree granting institution: Delft University of Technology

Program :Computer and Embedded Systems Engineering

Date: 10 Febuari 2026

Abstract:The Lunar Zebro team creates a rover that will be deployed on the lunar surface. The rover consists of multiple subsystems, each with its own power requirements. To ensure reliable operation, the rover is equipped with another subsystem, the Electrical Power System (EPS). This system distributes electrical power throughout the rover, continuously monitors the remaining energy stored in the battery pack, and manages the charging and discharging processes. The EPS also consists of a Battery management system (BMS) which monitors the batteries and keep them within a save voltage and current range. This thesis presents the design, implementation, and validation of a battery management system and battery pack for integration into the Lunar Zebro EPS. A conceptual EPS design with BMS and battery pack is created using energy budget estimation and power modeling. A simulation tool is developed to evaluate the charging and discharging behaviour during walking and charging scenarios of the rover throughout the mission. Based on these simulations, a suitable battery type is selected with focus on temperature tolerance, charging behaviour and reliable operation.
The Battery Management System developed in this work is designed and tested for its protective features, including overvoltage (OV) protection, undervoltage (UV) protection, overcurrent discharge (OCD) protection, and short-circuit discharge (SCD) protection. The BMS operates using I2C communication with an additional CRC bit to protect against bit errors. This work builds on earlier iterations of the existing EPS.
The BMS is built as a modular unit that can be integrated into the EPS. The bidirectional converter is also taken and redesigned as a separate module to improve accessibility and simplify debugging. This modular design improves development and testing at the cost of reduced compactness. Finally, the battery pack, the individual cells, and the BMS are tested to gain a clear understanding of the system behaviour in the rover. The results show that the BMS and the battery pack behave well and operate as intended. The integration of the bidirectional converter is shown to work conceptually. Some issues remain in the current physical board, which could not be resolved within the scope of this thesis and are left for future work.