LAUROPE – Participant of to the DLR SpaceBot Cup Competition

FZI is one of ten teams taking part in the DLR Space Administration (German Aerospace Center) space robotics competition SpaceBot Cup. The challenge of this competition is a planetary surface exploration mission. The tasks concentrate on locating, transporting and assembling objects – required for scientific experiments or construction of an infrastructure – in realistic, moonlike surroundings. The FZI team – LAUROPE – will send the hexapod robot LAURON V as well as a lander infrastructure to master the challenges posed by the competition.

There is always a particular kind of fascination about exploration missions. Current robot systems on Mars not only deliver high-resolution colour photographs, they also contribute to a better understanding of our neighbouring planet with their multitude of experiments and the results of their analyses. Further exploration of the Moon can not only expand the knowledge we have of our natural satellite, it can also deliver a new piece of the puzzle of better understanding our solar system.

The FZI team – LAUROPE – will assign this task to the hexapod robot LAURON V, supported by its lander infrastructure. During the exploration of the surroundings, there are obstacles that must be conquered or bypassed, and the assigned objects must be identified. Environmental modelling is of crucial importance. After the objects have been located, they are grasped with a special gripper, put in the transport container and taken to the target object, where they are accordingly installed. The whole operation is monitored by a control centre that provides the necessary flexibility and autonomy. In a real mission, the robot’s power supply would be extremely dependent on the location of the landing site, and this would influence the placement and orientation of solar cells. In this competition, the power is supplied by batteries.

The Robot LAURON

Roboter LAURON auf einer fiktiven Planetenoberfläche

LAURON IVc has proven successful in operations over the past seven years. The latest generation, LAURON V, was completed in 2012. As in the previous generations, the kinematic structure of the feet, the body and, above all, the walking patterns are modelled according to the biological role model of the stick insect. This enables the robots to reliably negotiate extremely unstructured and unknown surfaces.

The fifth LAURON generation is equipped with four degrees of freedom in each leg and is therefore capable of mastering even the steepest inclines. The specific alignment of the four hind legs allows the front legs to be used as gripping tools while the robot is standing on its just hind legs. Through ground contact sensors and 3D force sensors in its feet, as well as sensors measuring the electrical current in each joint, the robot is capable of probing the ground surface.

Technical Challenges

Gripping devices: In addition to the special leg alignment, special gripping devices are developed for manipulation tasks which are based on the current foot design. The grippers are retracted while the robot is walking.

Mapping and self-localization: The lander is equipped with a mast. This is where the high-resolution sensors for environment perception are placed (a panorama camera, rotating laser scanner). They help create a texturized 3D model of the lander’s surroundings. LAURON is additionally equipped with stereo or RGBD sensors which are used for a visual SLAM in order to continuously expand the initial environment model.

Suchstrategie LAURON

Navigation and search strategy: The search strategy is implemented using the Complete Coverage technique. By dividing navigation into global and local components, over-the-horizon navigation can be achieved – navigating beyond the initial sensory visual range. The local navigation is conducted with the help of RRTs and a behaviour-based control architecture.

Target object gripping and handling: Object models generated from 3D data allow the robot to plan grasps for arbitrary grippers in a proven and tested procedure. The actions should be fully or partly autonomous and can be monitored by an operator from a control centre. The control centre operation is based on our findings in the area of remote handling. This is where flexible autonomy plays a decisive role.

Team LAUROPE

In order to optimize LAURON for the competition, we need to tune and extend its software and hardware. These extensions are great topics for student papers (Bachelor, Master thesis etc.) as well as for internships and research assistant work.

Contact

Dipl.-Ing. Arne Rönnau

Further information about SpaceBot Cup and LAURON

LAURON Website (English)

LAUROPE SpaceBot Cup Blog (German)

SpaceBot Cup at DLR

LAURON Wikipedia article