Development Environment for Optimized Locomotion System of Planetary Rovers

This paper addresses the first steps that have been undergone to set up the development environement w.r.t optimization and to modelling and simulation of overall dynamics of the rover driving behaviour under all critical surface terrains, like soft and hard soils, slippage, bulldozing effect and digging in soft soil. Optimization is based on MOPS (Multi-Objective Prameter Synthesis), that is capable for handling several objective functions such as mass reduction, motor power reduction, increase of traction forces, rover stability guarantee, and more. The tool interferes with Matlab/Simulink and with Modelica/Dymola for dynamics model implementation. For modelling and simulation of the overall rover dynamics and terramechanical behaviour in all kind of soils we apply a Matlab based tool that takes advantage of the multibody dynamics tool Simpack. First results of very promising rover optimizations 6 wheels are presented that improve ExoMars rover type wheel suspension systems. Performance of driveability behaviour in different soils is presented as well. The next steps are discusses in order to achieve the planned overall development environment

Lunar Rover with Multiple Science Handling Capability

A rover design study was undertaken for exploration of the Moon. Rovers that have been launched in the past carried a suite of science payload either onboard its body or on the robotic arm’s end. No rover has so far been launched and tasked with “carrying and deploying” a payload on an extraterrestrial surface. This paper describes a lunar rover designed for deploying payload as well as carrying a suite of instruments onboard for conventional science tasks. The main consideration during the rover design process was the usage of existing, in-house technology for development of some rover systems. The manipulation subsystem design was derived from the technology of Light Weight Robot, a dexterous arm originally developed for terrestrial applications. Recent efforts have led to definition of a mission architecture for exploration of the Moon with such a rover. An outline of its design, the manipulating arm technology and the design decisions that were made has been presented

Preliminary Results for the Multi-Robot, Multi-Partner, Multi-Mission, Planetary Exploration Analogue Campaign on Mount Etna

This paper was initially intended to report on the outcome of the twice postponed demonstration mission of the ARCHES project. Due to the global COVID pandemic, it has been postponed from 2020, then 2021, to 2022. Nevertheless, the development of our concepts and integration has progressed rapidly, and some of the preliminary results are worthwhile to share with the community to drive the dialog on robotics planetary exploration strategies. This paper includes an overview of the planned 4-week campaign, as well as the vision and relevance of the missiontowards the planned official space missions. Furthermore, the cooperative aspect of the robotic teams, the scientific motivation, the sub task achievements are summarised

Finally! Insights into the ARCHES Lunar Planetary Exploration Analogue Campaign on Etna in summer 2022

This paper summarises the first outcomes of the space demonstration mission of the ARCHES project which could have been performed this year from 13 june until 10 july on Italy’s Mt. Etna in Sicily. After the second postponement related to COVID from the initially for 2020 planed campaign, we are now very happy to report, that the whole campaign with more than 65 participants for four weeks has been successfully conduced. In this short overview paper, we will refer to all other publication here on IAC22. This paper includes an overview of the performed 4-week campaign and the achieved mission goals and first results but also share our findings on the organisational and planning aspects

A systematic approach to reliably characterize soils based on Bevameter testing

Although there exists a lot of information about soil parameter identification in literature, currently there is no algorithm both making use of state of the art identification methodologies and incorporating statistical analysis. In this paper a state of the art soil parameter identification method is presented including the calculation of their standard deviations and a proper weighting of the objective function. With this algorithm and a Bevameter with advanced sensor and actuator technology a test campaign is started to find a reliable soil preparation which is applicable to a large planetary rover performance testbed. Furthermore the preparation method has to be valid and stable for various types of granular soils, typically used for planetary rover testing in space robotics, since the result of pre-tests show that the soil parameters are highly depending on the preparation. Besides to the preparation soil parameters are influenced by different Bevameter test setup variables, too. Thus the effect of the penetration velocity as well as the penetration tool geometry for pressure-sinkage tests on soil parameters is investigated. For shear tests the influence of the dimension of the shear ring is also analysed as the variation of the grouser height, the number of the grouser and the increase of the rotational shear velocity. The results of the extensive test campaign are evaluated by the proposed identification algorithms

A novel Terramechanics testbed setup for planetary Rover wheel-soil Interaction

For planetary rovers, demonstration of the overall mobility performance on soft soil is a demand to guarantee for mission success. Since several years, DLR’s Institute of Robotics and Mechatronics is strongly engaged in planetary mobile system developments. For the very important wheel-soil interaction a 3D-MBS tool for modeling and simulation of the overall terramechanics behavior, making use of Bekker’s well-known terramechnical equations, has been developed. Currently, major applications are followed within ESA’s Exomars mission. For the purpose of verification and validation of the 3D-MBS tool intensive hand in hand rover testing in a lab environment is necessary. Therefore, a new facility for planetary locomotion systems including a large testbed and a novel, high-precision bevameter to characterize the soil on which the tests are to be carried out is presented. For precise rover pose estimation inside the testbed a high-level position tracking system is used, and for proper soil surface determination on an in-house developed digital elevation mapping system is relied on. For the Bekker parameter determination, a portable and lightweight bevameter equipped with a state-of-the-art sensor technology is designed. Different design concepts are analysed open minded without any orientation on existing bevameter designs. This leads to a tripod design with electromechanical actuators and sensors integrated in a real-time computing environment to develop own control algorithms. Besides soil testing and soil preparation influence detection, the bevameter is mainly used for identifying soil parameters of the testbed. Finally, for correlation purposes, these parameters are taken as inputs to the 3D-MBS tool for simulating the drive manoeuvres performed inside the testbed. Results obtained from bevameter testing are presented together with the testbed setup design

Robotic On-Orbit Servicing - DLR's Experience and Perspective.

The increasing number of launched satellites per year, calls for solutions to keep free operational space for telecommunication systems in geo-synchronized orbit, as well as to avoid the endangering of space systems in LEO (Low-Earth Orbit) and of the public living in the habited parts on Earth. Examples for such dangerous stranded space systems in the past are Skylab and MIR. In the future, the uncontrolled and accidental de-orbiting of other huge satellites is expected, where parts of these will hit the surface of the Earth

Autonomous Planetary Surface Exploration: DLR Perspectives for Long-Range Mobility

Surface exploration by wheeled rovers on Earth's Moon (the two Lunokhods) and Mars (Nasa's Sojourner and the two MERs) have been followed since many years already very suc-cessfully, specifically concerning operations over long time. However, despite of this success, the explored surface area was very small, having in mind a total driving distance of about 8 km (Spirit) and 21 km (Opportunity) over 6 years of operation. Moreover, ESA will send its ExoMars rover in 2018 to Mars, and NASA its MSL rover this year in 2011. However, all these rovers are lacking sufficient on-board intelligence in order to overcome longer distances, driving much faster and deciding autonomously on path planning for the best trajectory to follow. In order to increase the scientific output of a rover mission it seems very necessary to explore much larger surface areas reliably in much less time. This is the main driver for a ro-botics institute to combine mechatronics functionalities to develop an intelligent mobile wheeled rover with four or six wheels, and having specific kinematics and locomotion sus-pension depending on the operational terrain of the rover to operate. DLR's Robotics and Mechatronics Center has a long tradition in developing advanced components in the field of light-weight motion actuation, intelligent and soft manipulation and skilled hands and tools, perception and cognition, and in increasing the autonomy of any kind of mechatronic systems. The whole design is supported and is based upon detailed modeling, optimization, and simula-tion tasks. We have developed efficient software tools to simulate the rover driveability per-formance on various terrain characteristics such as soft sandy and hard rocky terrains as well as on inclined planes, where wheel and grouser geometry plays a dominant role. Moreover, rover optimization is performed to support the best engineering intuitions, that will optimize structural and geometric parameters, compare various kinematics suspension concepts, and make use of realistic cost functions like mass and consumed energy minimization, static sta-bility, and more. For self-localization and safe navigation through unknown terrain we make use of fast 3D stereo algorithms that were successfully used on terrestrial mobile systems. The advanced rover design approach is applicable for lunar as well as Martian surface exploration purposes

A systematic approach to reliably characterize soils based on Bevameter testing

Although a lot of information about soil parameter identification exists in literature, there is currently no algorithm who makes use both of state of the art identification methodologies and incorporating statistical analysis. In this paper a state of the art soil parameter identification method is presented including the calculation of its standard deviations and a proper weighting of the objective function. With this algorithm and a Bevameter with advanced sensor and actuator technology a test campaign is started to find a reliable soil prep- aration, which is applicable to a large planetary rover performance testbed. Furthermore, the preparation method has to be valid and stable for various types of dry, granular and frictional soils, typically used for planetary rover testing in space robotics, since the result of pre-tests show that the soil parameters are highly depending on the preparation. Besides preparation, the soil parameters are also influ- enced by different Bevameter test setup variables. Thus, the effect of the penetration velocity as well as the penetration tool geometry for pressure–sinkage tests on soil parameters is investigated. For shear tests the influence of the dimension of the shear ring is analysed as well as the variation of the grouser height, the number of the grousers and the increase of the rotational shear velocity. The results of the extensive test campaign are evaluated by the proposed identification algorithms