Oberpfaffenhofen - The ROKVISS (Robotics Components Verification on the ISS) technology experiment developed by the German Aerospace Center (DLR) in Oberpfaffenhofen can now be directly controlled from the ground and set in motion in free space. From the DLR ground station in Weilheim, Upper Bavaria, the decisive tests were carried out in so-called telepresence mode with force feedback during an approximately six-minute overflight of the International Space Station ISS. This was the first time that a robot in space was controlled from Earth without any major time delay - a novelty in space robotics.
As early as March 2005, the German ROKVISS robot arm had successfully completed all tests in the so-called automatic mode. In this mode, previously programmed motion sequences transmitted to the International Space Station ISS were is processed independently by the robot arm. Now the tests in the so-called telepresence mode have also been positive. This proved that direct remote control of the robot arm from the ground and force feedback also work perfectly. This means that the robot arm, which is mounted on an outer platform of the International Space Station ISS, can now start its one-year experiment in open space in all areas.
Direct remote control of the robot arm in telepresence mode
In telepresence mode, the robot arm is controlled directly from the ground via the transmitting and receiving antenna in Weilheim (Southern Germany) during the overflight and moves in space with only a minimal time delay. In return, the scientist on Earth who operates the robot arm receives optical and sensory feedback of the robot arm's actions with only a minimal time delay. In concrete terms, this is achieved by transmitting stereo images in real time. Added to this is the force feedback, also transmitted with an extremely short time delay of around 20 milliseconds, which provides the scientist on the ground with direct sensory feedback about the forces generated in space. These forces occur, for example, when the robot arm sensitively scans the metallic contour mounted on the same outer platform in space.
Now that all the planned tests with the robot arm have been successfully completed, Professor Gerhard Hirzinger, Director of the DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen, explained: "We have now taken a major step forward in the development of new types of lightweight robots for cost-effective use in space and their convenient remote control from Earth". He emphasised: "With the successful completion of all tests of the robot arm impressively underpins its international top position in the field of space robotics".
The robot arm mounted on the International Space Station ISS, which is 50 centimetres in size and weighs seven kilograms, has two joints, a metal finger and two integrated cameras and is based on DLR's latest lightweight robot technology. In the future, it could play an important role in repair or assembly work in open space. The aim of the ROKVISS experiment planned and developed in Germany is to test and verify the new robot hardware and powerful control concepts in realistic mission operation and in free space. In the future, this innovative robot technology should support and relieve astronauts in complicated tasks. In addition, it could enable the repair of satellites under ground control.
On 24 December 2004, the German robot arm was brought to the ISS from the Russian spaceport Baikonur by a Russian Soyuz U rocket. Two astronauts took over the external assembly on 26 January 2005 during an approximately six-hour "space walk".
Important project for German space industry and research
The project is financed by the German Aerospace Center (DLR) with funds from the Federal Ministry of Education and Research (BMBF). As prime contractor, EADS Space Transportation in Bremen was responsible for system integration and for essential components of the on-board software. The DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen developed and built the robotic components and is responsible for conducting the experiments and for the scientific evaluation of the results. The Munich-based company Kayser-Threde is responsible for the development and construction of the experiment computer, the power supply and the technical support of the DLR institute. The company Hoerner & Sulger supplied the camera equipment with electronic accessories. The project is managed by DLR's Space Agency. The execution of the mission is based on an agreement between DLR's Space Agency, the Russian partners Roskosmos and RKK Energija and the Munich-based company Kayser-Threde as prime contractor for the S-band communication infrastructure.
The costs for the ROKVISS experiment amount to 11.5 million euros, including 3.5 million euros for launch, assembly and operation on the ISS, which Germany pays to the Russian contract partners.