Armin Wedler

Dynamics of a Tethered Rover on Rough Terrain

The deployment of a complex modular cable robot is investigated. The act is performed by a supporting rover that drives on rough terrain while pulling—and unwinding—one of the tethers. In order to avoid rebounds and stress spikes, the cable must be kept in tension by the feeding mechanism. In this work, a constant torque control system is evaluated. A numerical simulation is carried out by direct time-integration of the dynamics equation of the cable and the drive. Results show that a constant torque applied by the motor unit is able to produce a tension in the cable that is well within the cable’s yield limits, while at the same time being consistently larger than zero. This shows the viability of this technology for the deployment of cable structures by rovers in extreme environments.

The Network Infrastructure for the ROBEX Demomission Space

The demonstration mission space of the alliance Robotic Exploration of Extreme Environments (ROBEX) was a campaign on Mt. Etna in summer 2017. The network infrastructure and parts of the ground segment for this demonstration mission space were set up by the Mobile Rocket Base (MORABA) of the DLR. The ground segment included a control center which was based near Catania, Italy. Various terminals allowed for controlling a lander, a robotic rover and several experiment carriers which have been placed in 23 km airline distance on Mt. Etna. The distance was bridged by a radio link between the control center and a base camp at the demonstration site. From the base camp a shorter radio link of several hundreds of meters to the lander was established, and from there, the signal was distributed using several access points.

A Study on the End-Effector Exchange Mechanism of a Space Robot

This study investigates the necessity for space robots to independently exchange their end-effectors due to the contradiction that exists between the requirements of various robots in space missions and the payload capacity limits of rockets. The results of this study summarize the system requirements for a new end-effector exchange mechanism, including compact size, misalignment tolerance, and regolith tolerance. This is followed by the development of a prototype model with a set of test apparatus. Then the function of the prototype is verified, the prototype is optimized, and the relation between docking force and misalignment is examined through operation tests.