On Advanced Mobility Concepts for Intelligent Planetary Surface Exploration

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 probably this year. However, all these rovers are lacking sufficient on-board intelligence in order to overcome longer dis-tances, driving much faster and deciding autonomously on path planning for the best trajec-tory to follow. In order to increase the scientific output of a rover mission it seems very nec-essary to explore much larger surface areas reliably in much less time. This is the main driver for a robotics institute to combine mechatronics functionalities to develop an intelligent mo-bile wheeled rover with four or six wheels, and having specific kinematics and locomotion suspension 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 e.g. in unmanned air vehicle ap-plications and on terrestrial mobile systems. The advanced rover design approach is applica-ble for lunar as well as Martian surface exploration purposes. A first mobility concept ap-proach for a lunar vehicle will be presented

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

Navigation of mini swimmers in channel networks with magnetic fields

Controlled navigation of swimming micro robots inside fluid filled channels is necessary for applications in living tissues and vessels. Hydrodynamic behavior inside channels and interaction with channel walls need to be understood well for successful design and control of these surgical-tools-to-be. In this study, two different mechanisms are used for forward and lateral motion: rotation of helices in the direction of the helical axis leads to forward motion in the viscous fluid, and rolling due to wall traction results with the lateral motion near the wall. Experiments are conducted using a magnetic helical swimmer having 1.5 mm in length and 0.5 mm in diameter placed inside two different glycerol-filled channels with rectangular cross sections. The strength, direction and rotational frequency of the externally applied rotating magnetic field are used as inputs to control the position and direction of the micro swimmer in Y- and T-shaped channels