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In planetary exploration, testing under the actual mission conditions is inherently not possible. Hence, simulation campaigns complement ground test campaigns. This specially applies to surface missions that include the complex behaviour of soils under non-terrestrial gravitation. Increasingly ambitious mission goals made large simulation campaigns with very precise particle models necessary for the simulation of soil interaction. Thus, to limit the amount of time and the computation hardware needed, DLR developed the particle simulation tool “Sir partsival”. This tool does not only speed up simulations by usage of GPU computing, but also integrates the institute’s experience in modelling of soil on Earth and beyond. Using partsival it was possible to speed up simulations by more than a factor of ten and thus conduct large simulation campaigns. Two examples are shown: a large, on-going validation campaign of DEM for wheel simulations, and the completed traction optimization for the MMX rover wheel.

JAXA's Martian Moons eXploration Mission (MMX) includes the delivery of an exploration rover to the Mars moon Phobos in 2026, engineered by the Centre National d’Etudes Spatiales (CNES) and the German Aerospace Center (DLR). On Phobos, the gravity is about two thousand times lower than on Earth, which is why it is also called a milli-g environment. While the actual surface of Phobos is largely unknown, it is agreed within mission team that areas covered with regolith are to be expected. The design of the rover includes four actuated legs, with one rotational degree of freedom (DOF) each, and four individually driven, non-steerable wheels. The first task of the rover after landing on the surface of Phobos will be to deploy itself from its cruise configuration and to stand up on its wheels. Due to the rover dimensions, a full rotation of the legs and a wheel slip compensation are essential for this task. During operations, the locomotion system needs to provide drive and steer, as well as point turn abilities. Furthermore, the solar panel sun pointing, as well as the adjustment of scientific instruments, require that the rover aligns its body orientation and alters its body-to-ground distance. To satisfy all these requirements to the locomotion system of the MMX rover, appropriate locomotion control functions were developed. For driving curves and performing point turns, the skid steering method is applied and an “inching” locomotion mode for especially soft and steep terrain is adapted. In this inching locomotion, the front and rear wheel pair move alternately while the rover body moves up and down, which leads to enhanced traction performance compared to conventional driving in soft sand. This implies lower wheel slippage and sinkage resulting in a higher safety of the full rover system. The body orientation function, which is based on a kinematic control as well, provides a well coordinated movement and zero longitudinal slippage of the wheels during its execution. In this paper, a detailed description of the control algorithms is given and results from lab tests are presented and discussed. In a successful mission, these locomotion control functions will be the first ones actuating a wheeled mobile robot in milli-g environment.

Space missions to explore Mars and Moon in situ are of high interest, but hazard terrain with steep slopes, soft soil, loose stones or high obstacles are a barrier for exploration rovers with common wheels. It was shown that rimless wheel rovers yield an enhanced performance in those environments while letting the complexity of the rover unchanged. They can cross higher obstacles, have a significant lower likelihood to get stuck and can move faster compared to common wheel rovers. At the Institute of System Dynamics and Control at the German Aerospace Center (DLR), a modular rimless wheel rover with flexible elements was designed for the purpose of planetary exploration in the above mentioned terrain. Due to the rimless wheels, the wheel circumference is not uniform. Hence, for an improved controllability of the full rover locomotion, it is reasonable to have control over the angular position of each wheel and especially over their angular position relative to each other. In this paper, several of these phase shifts are presented and compared. A setup in which the rover is driving straight forward is chosen to compare the behavior and performance of the different wheel configurations. The roll angle as well as the vertical movement of each rover segment are measured in simulation for different rover speeds and different phase shifts. A comparison between the different phase shift schemes in the sense of their waviness is made. The phase offsets have to be adjusted by means of a controller such that disturbances do not interfere significantly. For that reason, a PI controller was implemented. The study presented in this paper shows how the locomotion performance of a rimless wheel rover with compliant spokes can be improved by a well-tuned wheel position controller and the right choice of the phase shift configuration.

Understanding social behaviour in livestock groups requires accurate geo-spatial localisation data over time which is difficult to obtain in the field. Automated on-animal devices may provide a solution. This study introduced an Real-Time-Kinematic Global Navigation Satellite System (RTK-GNSS) localisation device (RTK rover) based on an RTK module manufactured by the company u-blox (Thalwil, Switzerland) that was assembled in a box and harnessed to sheep backs. Testing with 7 sheep across 4 days confirmed RTK rover tracking of sheep movement continuously with accuracy of approximately 20 cm. Individual sheep geo-spatial data were used to observe the sheep that first moved during a grazing period (movement leaders) in the one-hectare test paddock as well as construct social networks. Analysis of the optimum location update rate, with a threshold distance of 20 cm or 30 cm, showed that location sampling at a rate of 1 sample per second for 1 min followed by no samples for 4 min or 9 min, detected social networks as accurately as continuous location measurements at 1 sample every 5 s. The RTK rover acquired precise data on social networks in one sheep flock in an outdoor field environment with sampling strategies identified to extend battery life.

In this paper, we present a user-friendly planetary rover's control system for low latency surface telerobotic. Thanks to the proposed system, an operator can comfortably give commands through the control base station to a rover using commercially available off-the-shelf (COTS) joysticks or by command sequencing with interactive monitoring on the sensed map of the environment. During operations, high situational awareness is made possible thanks to 3D map visualization. The map of the environment is built on the on-board computer by processing the rover's camera images with a visual Simultaneous Localization and Mapping (SLAM) algorithm. It is transmitted via Wi-Fi and displayed on the control base station screen in near real-time. The navigation stack takes as input the visual SLAM data to build a cost map to find the minimum cost path. By interacting with the virtual map, the rover exhibits properties of a Cyber Physical System (CPS) for its self-awareness capabilities. The software architecture is based on the Robot Operative System (ROS) middleware. The system design and the preliminary field test results are shown in the paper., Comment: To be presented at the 8th IEEE International Workshop on Metrology for Aerospace (MetroAeroSpace)

Path planning is an essential technology for lunar rover to achieve safe and efficient autonomous exploration mission, this paper proposes a learning-based end-to-end path planning algorithm for lunar rovers with safety constraints. Firstly, a training environment integrating real lunar surface terrain data was built using the Gazebo simulation environment and a lunar rover simulator was created in it to simulate the real lunar surface environment and the lunar rover system. Then an end-to-end path planning algorithm based on deep reinforcement learning method is designed, including state space, action space, network structure, reward function considering slip behavior, and training method based on proximal policy optimization. In addition, to improve the generalization ability to different lunar surface topography and different scale environments, a variety of training scenarios were set up to train the network model using the idea of curriculum learning. The simulation results show that the proposed planning algorithm can successfully achieve the end-to-end path planning of the lunar rover, and the path generated by the proposed algorithm has a higher safety guarantee compared with the classical path planning algorithm.

En este trabajo se desarrollan algoritmos de visión por ordenador e Inteligencia Artificial que permiten estimar la posición y localización de un vehículo mediante odometría visual y además reconocer y clasificar objetos del entorno. En concreto, se diseñan algoritmos que permiten calibrar un sistema de cámaras estéreo, estimar la pose de un objeto y generar mapas de disparidad y profundidad con reconocimiento y clasificación de objetos. Se analizan los fundamentos teóricos necesarios para diseñarlos y se muestran los resultados obtenidos en cada uno de los algoritmos. También se discuten las ventajas y desventajas de las técnicas empleadas. Para ello se trabaja en Python con la ayuda de paquetes de visión y segmentación de imagen, como OpenCV y PixelLib. Asimismo, se realiza una revisión acerca del estado del arte en técnicas de posicionamiento de vehículos de exploración y detección y clasificación de objetos. Se hace una estudio sobre las técnicas visuales empleadas en misiones de exploración espacial pasadas y futuras. In this work, computer vision and AI algorithms are developed using visual odometry in order to estimate the position and location of a vehicle and also to recognize and classify objects in the environment. Specifically, algorithms that allow stereo cameras calibration, object pose estimation and disparity and depth map generation with object recognition and classification are designed. Theoretical fundamentals needed to design them are analysed and results in each algorithm are shown. Advantages and disadvantages of these techniques are also discussed. To do this, we work in Python together with vision and image segmentation packages such as OpenCV and PixelLib. A review about the State of the Art in techniques for pose estimation in exploration vehicles and object recognition and classification is done. Visual techniques applied in past and future space exploration missions are also analysed. Lan honetan ordenagailu bidezko ikusmen- eta adimen artifizialeko algoritmoak garatzen di- ra, ikusmen-odometria erabiliz ibilgailu baten posizioa eta kokapena balioesteaz gain inguruneko objektuak antzematea eta sailkatzea ahalbidetzen dutenak. Zehazki, estereo kamera sistema bat kalibratzea, objektu baten posea balioztatzea, eta desberdintasun- eta sakontasun-mapak sortzea ahalbidetzen duten eta objektuak antzeman eta sailkatu ditzaketen algoritmoak diseinatzen dira. Horiek diseinatzeko behar diren oinarri teorikoak aztertzen dira eta algoritmo bakoitzean lortutako emaitzak erakusten dira. Erabilitako tekniken abantailak eta desabantailak ere eztabaidatzen dira. Horretarako Python-en lan egiten da, OpenCV eta PixelLib bezalako irudi segmentazio eta ikusmen paketeen laguntzarekin. Halaber, Artea-Egoeraren berrikuspen bat egiten da esplorazio-ibilgailuak kokatzeko eta objektuak detektatu eta sailkatzeko tekniketan. Iraganeko eta etorkizuneko espazio- esplorazioko misioetan erabilitako ikus-teknikei buruz azterketa bat ere egin da.

This paper develops a haptic feedback control stick for remote control of a two parallel wheeled rover. The authors apply a bilateral controller for this remote operating-operated system in which their structures are different. Thus, the developed haptic feedback control stick plays a role as not only an input device to give the velocity information to the system but also an output device by which the operator feels an estimated external force applied to the wheel of the rover. The haptic feedback control stick is strongly expected the operator can control the operated rover more intuitively and more safely. In this paper, the authors experimented by combining a linear-slide-type control stick and a single wheel computer simulator of the rover. However, the operator felt a force except the estimated force to the rover's wheel, in conditions that a time delay occurred because of a large dynamical difference between the control stick and the rover. Therefore, two types of experiments were compared, i.e., one used only the bilateral control and the other used switching the bilateral control and the force control according to a value of the time delay. These experimental results were discussed and evaluated as focusing on a situation when a time delay occurred.

En el presente Trabajo de Fin de Grado se expone el estudio de un róver con suspensión rocker-bogie para misiones en Marte. Pero, y por qué Marte? Primero, porque es el planeta más cercano a la Tierra y guardan infinitas coincidencias, hasta el punto de que se piensa que Marte pudo tener océanos y vida como en el planeta azul. Y segundo, porque tiene una serie de paisajes, relieves e incluso volcanes y cráteres que lo hacen especial y que llama la atención para poder ser estudiados. He aquí donde sale la curiosidad de este estudio, conocer Marte y conocer cómo este se puede estudiar de primera mano, es decir, desde la propia superficie. De esta manera, se pretende estudiar no solo Marte y su superficie, sino también las diferentes posibilidades de suspensiones que se pueden albergar en un róver, sus componentes esenciales con sus respectivos materiales para poder entender el mecanismo de funcionamiento y qué le hace especial al tipo rocker-bogie frente a los demás, además de diseñarlo en función de la región del planeta elegido en este estudio, para que sea capaz de adaptarse al terreno y superar los obstáculos de la mejor manera. Finalmente, se crea un prototipo final de manera virtual del róver para poder mostrar el resultado y objetivo del estudio, a parte de intentar inspirar a la sociedad y a la próxima generación de jóvenes estudiantes de desarrollar la exploración espacial y de intentar, por qué no, en unos años, el primer asentamiento humano en Marte

In this work, the problem of localizing ground devices (GDs) is studied comparing the performance of four range-free (RF) localization algorithms that use a mobile anchor (MA). All the investigated algorithms are based on the so-called heard/not-heard (HnH) method, which allows the GDs to detect the MA at the border of their antenna communication radius. Despite the simplicity of this method, its efficacy in terms of accuracy is poor because it relies on the antenna radius that continuously varies under different conditions. Usually, the antenna radius declared by the manufacturer does not fully characterize the actual antenna radiation pattern. In this paper, the radiation pattern of the commercial DecaWave DWM1001 Ultra-Wide-Band (UWB) antennas is observed in a real test-bed at different altitudes for collecting more information and insights on the antenna radius. The compared algorithms are then tested using both the observed and the manufacturer radii. The experimental accuracy is close to the expected theoretical one only when the antenna pattern is actually omnidirectional. However, typical antennas have strong pattern irregularities that decrease the accuracy. For improving the performance, we propose range-based (RB) variants of the compared algorithms in which, instead of using the observed or the manufacturer radii, the actual measured distances between the MA and the GD are used. The localization accuracy tremendously improves confirming that the knowledge of the exact antenna pattern is essential for any RF algorithm.

The exploration of Mars, which began in the 1960s, will soon be marked by a historic turning point, with the in situ investigation of two sites of Noachian age, the most primitive era of Mars. The selected landing sites, Jezero crater and Oxia Planum, exhibit from orbital data evidences for a hydrous past as well as good astrobiological potentials. The two rovers Perseverance and Rosalind Franklin (sent by the American and European-Russian agencies respectively) have a payload which includes the first visible and near-infrared (VNIR) reflectance spectrometers that will be used on the Martian surface, while this technique is the first to be used from orbit to assess and map the mineralogy of Mars. Our thesis is divided into two segments: first, an analysis of the two landing sites using remote sensing data was carried out, in order to characterize their geology and mineralogy. Second, terrestrial rocks similar to those on the landing sites were collected and analyzed using a reflectance spectrometer whose analysis beam is comparable in size to that of the VNIR channel of the SuperCam spectrometer onboard Perseverance. Our analysis on the Perseverance landing site allowed to examine the mineralogical variations of one of the most extensive geological units on the site, the olivine and carbonate unit. We suggest a pyroclastic origin for these deposits and date their emplacement at -3.82 +/- 0.07 Ga. This age will be useful to help calibrate the Martian chronology in the events of the Mars Sample Return mission. While Rosalind Franklin's landing site appears spectrally homogeneous from orbit, we show that there is textural, compositional, and mineralogical diversity at high resolution within the clays present at the site, which are the primary targets of the mission. During this thesis, we have produced a spectral database of samples analyzed in the laboratory. The reflectance spectra can be directly and automatically compared to those that will be measured in situ on rock outcrops. This database includes the first representative panel of Martian meteorites, natural magmatic rocks more or less altered and whose mineralogical compositions have been estimated, as well as synthetic mixtures of simplified composition and mineralogy that are directly comparable to those estimated on the landing sites. The reflectance spectra measured could be directly and automatically compared to future in situ measurements on Martian rock surfaces, L’exploration spatiale de la planète Mars sera marquée dans la prochaine décennie par une étape historique : l’exploration in situ de terrains d’âge noachien, soit faisant partie des plus anciens de la planète. Les sites d’atterrissage sélectionnés, le cratère Jezero et Oxia Planum, présentent depuis l’orbite les traces d’une activité hydrologique ancienne, ainsi qu’un potentiel exobiologique. Les deux rovers envoyés pour explorer ces sites (Perseverance par la NASA, et Rosalind Franklin par l’ESA et Roscosmos), sont équipés des premiers spectromètres de réflectance visible et proche-infrarouge (VNIR) à toucher le sol martien, alors que cette technique de détection est la première utilisée depuis l’orbite pour détecter et cartographier les minéraux en surface. Nos travaux de thèse sont découpés en deux axes : dans un premier temps, une analyse des deux sites d’atterrissage par télédétection a été effectuée, afin d’avancer sur leur caractérisation géologique et minéralogique. Dans un second temps, des roches terrestres analogues aux sites d’atterrissage ont été collectées et analysées à l’aide d’un spectromètre de réflectance dont le faisceau d’analyse est comparable en taille à celui de la voie VNIR du spectromètre SuperCam du rover Perseverance. Notre analyse sur le site d’atterrissage de Perseverance a permis de carter les variations minéralogiques d’une des unités géologiques les plus étendues sur le site, l’unité à olivine et carbonate, de proposer une origine pyroclastique, et d’en dater la mise en place il y a 3,82 +/- 0,07 Ga. Cet âge pourra être utilisé dans l’optique du retour des échantillons collectés par Perseverance, afin de calibrer la chronologie martienne. Là où le site d’atterrissage de Rosalind Franklin apparaît spectralement homogène depuis l’orbite, nous montrons qu’il existe à haute résolution une diversité morphologique, compositionnelle et minéralogique au sein des argiles présentes sur le site, cibles principales de la mission. Au cours de ces travaux de recherche, nous avons produit une base de données spectrale sur des échantillons analysés en laboratoire. Cette base de données inclut le premier panel représentatif de météorites martiennes, des roches terrestres naturelles dont la composition minéralogique a pu être estimée grâce à la diffraction de rayons X, ainsi que des mélanges synthétiques de composition simplifiée et de minéralogie directement transposable à celle estimée sur les sites d’atterrissage. Ces spectres de réflectance pourront être directement et automatiquement comparés à ceux mesurés sur des affleurements rocheux in situ

El riego poco controlado de pesticidas en cultivos de cebolla larga en Aquitania (Boyacá) y el bajo acceso a tecnologías agrícolas, limitan las posibilidades de los pequeños productores (que constituyen la mayoría) de emprender proyectos con mayor alcance y rentabilidad. La implementación de un robot agrícola capaz de aplicar riegos en las condiciones de pendiente considerable, sin conexión constante a la fuente eléctrica, es una alternativa que permitiría unificar los cambios en estas tecnologías a nivel global con la tecnificación escasa en el campo colombiano. En el presente proyecto, se desarrolló un prediseño de un rover, seleccionando los componentes mas esenciales de los subsistemas motriz (o tracción con el suelo), suspensión, almacenamiento y bombeo y de adquisición de datos e interfaz con el usuario. Así mismo, el enfoque detallado fue hacia el diseño de un manipulador robótico planar, acoplado al sistema de bombeo. Este manipulador se basa en el robot UR5, con la diferencia de que se tienen tres grados de libertad, y el movimiento en cada junta es bidimensional (todos en el mismo plano). Las dimensiones generales del rover, así como las restricciones de movimiento del manipulador, se basan en la predisposición de los cultivos de 40 cm entre plantas y 80 cm entre surcos, y la altura de entre 30 y 90 cm de las plantas. A partir de esta información, se obtuvo un espacio de trabajo circular, se dimensionaron las longitudes de los eslabones y se desarrolló la cinemática y la cinética del mecanismo. Mediante el desarrollo de las expresiones matriciales y la simulación en sicmechanics en MATLAB, se logró realizar el cálculo de posiciones, velocidades, aceleraciones y momentos, así como una trayectoria suavizada. De este modo, se logró desarrollar un diseño de manipulador robótico para el riego en cultivos de cebolla larga, con un desempeño mas preciso y de igual capacidad de trabajo (en tiempo y área) que al emplear mano de obra para la misma tarea.

Stack, K. et al., The Mars 2020 Perseverance rover landing site is located within Jezero crater, a ∼50km diameter impact crater interpreted to be a Noachian-aged lake basin inside the western edge of the Isidis impact structure. Jezero hosts remnants of a fluvial delta, inlet and outlet valleys, and infill deposits containing diverse carbonate, mafic, and hydrated minerals. Prior to the launch of the Mars 2020 mission, members of the Science Team collaborated to produce a photogeologic map of the Perseverance landing site in Jezero crater. Mapping was performed at a 1:5000 digital map scale using a 25 cm/pixel High Resolution Imaging Science Experiment (HiRISE) orthoimage mosaic base map and a 1 m/pixel HiRISE stereo digital terrain model. Mapped bedrock and surficial units were distinguished by differences in relative brightness, tone, topography, surface texture, and apparent roughness. Mapped bedrock units are generally consistent with those identified in previously published mapping efforts, but this study’s map includes the distribution of surficial deposits and sub-units of the Jezero delta at a higher level of detail than previous studies. This study considers four possible unit correlations to explain the relative age relationships of major units within the map area. Unit correlations include previously published interpretations as well as those that consider more complex interfingering relationships and alternative relative age relationships. The photogeologic map presented here is the foundation for scientific hypothesis development and strategic planning for Perseverance’s exploration of Jezero crater., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

It is one of the developing directions of deep space exploration in the future to carry out surface wide patrol detection of extraterrestrial bodies by unmanned or manned means. Whether the unknown complex surface environment can be accurately and efficiently identified is the key problem affecting the detection efficiency. This paper explored the method of obstacle detection on two-dimensional images of the surface of extraterrestrial bodies by deep learning and transfer learning techniques. The main contents of this paper included training data acquisition, neural network model training using transfer learning, and the obstacle detection. The method in this paper had been verified with the ground prototype of "Yutu" rover in the simulated lunar surface test site, and could identify rocks, slopes and other obstacles as well as the test prototype itself, laying a foundation for further research and engineering application in the future.

The Curiosity rover investigated a topographic structure known as Vera Rubin ridge, associated with a hematite signature in orbital spectra. There, Curiosity encountered mudstones interpreted as lacustrine deposits, conformably overlying the 300 m‐thick underlying sedimentary rocks of the Murray formation at the base of Mount Sharp. While the presence of hematite (α‐Fe2O3) was confirmed in‐situ by both Mastcam and ChemCam spectral observations and by the CheMin instrument, neither ChemCam nor APXS observed any significant increase in FeOT (total iron oxide) abundances compared to the rest of the Murray formation. Instead, Curiosity discovered dark‐toned diagenetic features displaying anomalously high FeOT abundances, commonly observed in association with light‐toned Ca‐sulfate veins but also as crystal pseudomorphs in the host rock. These iron‐rich diagenetic features are predominantly observed in “grey” outcrops on the upper part of the ridge, which lack the telltale ferric signature of other Vera Rubin ridge outcrops. Their composition is consistent with anhydrous Fe‐oxide, as the enrichment in iron is not associated with enrichment in any other elements, nor with detections of volatiles. The lack of ferric absorption features in the ChemCam reflectance spectra and the hexagonal crystalline structure associated with dark‐toned crystals points toward coarse “grey” hematite. In addition, the host rock adjacent to these features appears bleached and show low‐FeOT content as well as depletion in Mn, indicating mobilization of these redox‐sensitive elements during diagenesis. Thus, groundwater fluid circulations could account for the remobilization of iron and recrystallization as crystalline hematite during diagenesis on Vera Rubin ridge.