Description

The 288 square meter space exploration hall allows to test space robots under realistic conditions. Systems such as the SpaceClimber robot can demonstrate their skills in the 9 meters wide crater test area within the test hall. The surface was modeled based on a crater at the south pole on the moon. The surface can be altered, rock segments can be exchanged for certain tests on different undergrounds. An additional 18 square meter ramp on a four meter high plateau at the head of the crater area is adjustable in its gradient degree. In this way it is possible to test the mobility of the robot on a horizontal ground and on varying slopes. For similar light conditions to the moon, the inner walls are furnished with a black non-reflective coating. Here, researchers have already been practicing for a future mission to the moon.

With a height of ten meters, the space hall provides enough space for testing flight systems as well as interactions between satellites and robots. With the project INVERITAS the DFKI researchers are simulating the capture of no longer controllable satellites by a so-called „Servicing Satellite“. It is mounted on a moveable cable-robot. Supported by eight ropes, the system moves through the air while approaching the client-satellite which is to be captured. An industrial robotic arm on the floor of the hall creates the movement of the client-satellite, which is attached to this arm.

The costs for the construction and the equipment of the space exploration hall totaled around 600,000 Euro. The expenses are shared equally between the DFKI-Companion Astrium GmbH, the WFB Wirtschaftsförderung Bremen GmbH, and the DFKI.

Below you will find information about the technical equipment:

Space Exploration Hall

Contact person: Public relations HB

Moonscenario, photographer: Michael Joos
Moonscenario, photographer: Michael Joos

Hall

In 2010, the space exploration hall was added to the main building of the DFKI Bremen. This hall has a length of 24 meters, a width of 12 meters, and a height of 10 meters.

computergrafic of the hall
computergrafic of the hall
topview with work area of the cable bot
topview with work area of the cable bot
exterior shot of the hall
exterior shot of the hall

Video

Learn more about our Space Exploration Hall

System for long-distance movement simulation (LDMSS)

The space exploration hall can be used for HIL(Hardware in the loop)-Simulations. For example, for docking, capture, and landing maneuvers in space. The spacecrafts, e.g. autonomously docking satellites or lunar lander, which are moved in a simulation, can be moved synchronously with the software simulation in the hall. Therefore, real sensors can be used as HIL and the measurement data can be used for the simulation.

The LDMSS is directly coupled with a newly developed modular software simulator and a 3D visualization. It is possible to implement and evaluate different ways of movement simulation und to control up to two space vehicles. The software simulator is transmitting the results stepwise to the physically existent LDMSS. This ensures that software and hardware supply the same results.

The physical technology demonstrators which can move up to two spacecraft-mockups are brought together by a six-axis robot and a cable-guided 3D motion system (Cable-robot) for the LDMSS. For accurate positioning, the LDMSS also has a visual tracking system through which the current position of the cable-robot can be determined. During the transmission of the simulation results to the LDMSS, the total of 12 unlimited degrees of freedom of the real spacecrafts are converted to the limited 10 degrees of freedom of the robot and the cable-guided motion system. The LDMSS is set up in an environment in which it is possible to control the complete lighting conditions through black-painted walls and a reconfigurable modular lighting system. Therefore, many physical parameters of a space mission can be simulated, evaluated, and demonstrated.

Cable-robot

The cable-robot is a modified version of a robot camera from the company "SpiderCam". The robot is attached to 8 ropes, which can be controlled in length with 4 winches and pulleys, so that the mount of the cable-robot is able to reach any X,Y and Z-coordinate within its workspace with three translational degrees of freedom.

computergrafic
computergrafic
jack of the cable robot
jack of the cable robot
cable robot with vehicle load capacity
cable robot with vehicle load capacity
Technical details
number of cables:8
number of winches:4
core of the work area:6 m x 4 m x 4,50 m
repeat accuracy in core of the work area:ca. +/- 5 mm
extended work area:16 m x 7 m x 5,50 m (LxBxH)
min. translational speed:0,1 mm/s
max. translational speed:2 m/s
max. acceleration:1,5 m/s²
load capacity (constant):150 kg
data rate to/from Mount:10 GBit/s via fiber optics, switch on Mount
power supply on Mount:230 V AC mit 1 kW, 24 V DC
activation:CAN
cycle time:4 ms

The core of the work area of the cable-robot covers an area of 6 m x 4 m x 4.50 m (length x width x height). The exact position of the cable-robot can be determined using only the length of the ropes. The extended area without visual tracking and with less precise control extends over 16 m x 7 m x 3.50 m.

The cable-robot can move with velocities between 0.1 mm/s and 2 m/s. The maximum acceleration is 1,5 m/s². To achieve high motion stability, the used payload of the cable robot is held constantly at 150 kg. If this limit is not already generated by the payload, additional weights are attached to the mount.

Kabelroboter im Versuch
Kabelroboter im Versuch
Computergrafik Zusammenspiel von KUKA und Kabelroboter
Computergrafik Zusammenspiel von KUKA und Kabelroboter
KUKA und Kabelroboter
KUKA und Kabelroboter

Each of the 4 winches simultaneously controls 2 of the 8 ropes. The top rope of the winches 1 and 2 is used for data transmission over fiber optic lines with up to 10 Gbit/s. A switch is located at the mount to distribute data communication via ethernet. The ropes of the winches 3 and 4 are responsible for power supply at the mount. 230 V AC and 24 V DC with 1 kW power are available on the mount. The cable-robot itself is controlled via CAN-Bus.

To increase the number of degrees of freedom of the cable-robot from 9 to 10, there is a controllable z-axis  attached to the mount of the cable-robot.

To determine and control the position, the current cable length of the cable-robot is consulted internally. Thereby, a repeatability of about +/- 5 mm is achieved. Independently from the cable-robot system, the position of the mounts can also be determined via the visual tracking system. To control the cable-robot, both systems are used in combination.

KUKA-robot-arm

One of the two simulated spacecrafts is held by a robotic arm of the trademark "KUKA", Model KR-60-3 and is moved according to the simulation.

Computergrafic of KUKA KR-60-3
Computergrafic of KUKA KR-60-3
Computergrafic of KUKA KR-60-3
Computergrafic of KUKA KR-60-3
Foto of KUKA KR-60-3
Foto of KUKA KR-60-3
degrees of freedom:6
loading capacity:60 kg
activation:Remote Sensor Interface (RSI) via Ethernet-Interface
cycle time:12 ms
repeat accuracy:+/- 0,2 mm

The KUKA KR-60-3 has six degrees of freedom and a maximum payload of 60 kg. It can be controlled via an Ethernet interface to the remote sensor interface (RSI), in a cycle time of 12 ms between each position command. When approaching the positions, the KUKA reaches a repeatability of + / - 0.2 mm.

operating range of KUKA KR-60-3
operating range of KUKA KR-60-3

Data according to the workspace of KUKA KR-60-3:

measureABCDEFG
length (in mm)24983003203312188151084820
axisA1A2A3A4A5A6
angle range±185° +35°/-135°+158°/-120°±350° ±119° ±350°
max. angular velocity128°/s102°/s128°/s260°/s245°/s322°/s

VICON-Tracking-System

camera of the VICON-Tracking-system
camera of the VICON-Tracking-system

The VICON tracking system uses six cameras mounted in a height of 6.5 m each and cover a volume of about 770 cubic meters. Three cameras are distributed on each of the two long sides of the hall. A seventh camera can be positioned flexibly to reach higher accuracy in varying volumes of the hall. The tracking system can be controlled with variable speeds between about 4 ms and 12 ms. The cameras operate in the infrared wavelength range and actively transmit the light in this band. Markers are attached to the cable-robot to determine the position which in this wavelength region has a high reflection coefficient and hence can be detected particularly well by the tracking system.

number of cameras:6
covered volume:ca. 770 m³
cycle time:ca. 4 ms – 12 ms
wavelength range
(received and sent):
Infrared

Control Station

Because the light conditions should simulate the darkness of space, the events in the hall cannot only be observed directly but also with 9 highly sensitive surveillance-cameras.

Both looking at the images of the surveillance-cameras and controlling of LDMSS is possible from the control room. This is located in the southeastern corner of the hall at a height of 7 m. Depending on the chosen lighting conditions, the windows in the control room allow a direct observation of the events in the hall. The software simulation also is performed here, and can be converted into various stages to the hardware simulation. Additionally, there is a second control console at the middle level.

Crater area

contact person:Florian Cordes

traces of SpaceClimber, photographer: Michael Joos
traces of SpaceClimber, photographer: Michael Joos

The crater area has been reconstructed based on data of real south pole craters from the moon and photos of the Apollo missions. The crater provides gradients of 15° to 45° for experiments. There are three continuous paths with a slope with 25°, 35° and 45°. The crater is used for testing of free-climbing robotic systems and to visualize the robotic developments for exploration activities at the DFKI RIC. The load capacity of the landscape is designed for large systems too.

testing facilities in the hall
testing facilities in the hall
crater surface:105 m²
width:9,5 m 
height of crater edge:4,5 m 
carrying capacity of surface:500 kg/m²

Adjustable ramp

For better repeatability and clearly defined experimental conditions, a variable ramp exists on the upper plateau crater offering gradients from 0° to 45° in 5 ° increments in either longitudinal or transverse direction. In the 3 m x 6 m bed of the ramp, variable 1 m² floor panels can be installed for different undergrounds. There is also the possibility to fill the ramp with loose sediments. Currently, three substrates with different grain sizes are available at the DFKI.

surface:18 m² (3 m x 6 m)
adjustable area:0°-45° in two directions
increment:5° steps
surface material:variable: interchangeable base elements and loose substrates

Headlight-system

headlights
headlights
number of cable control:5
max. number of headlight per cable:3
number of headlights in hall:6
headlight type:ADB Warp motorisch

The headlights have a color temperature of 6000 K and produce daylight conditions. With the ability to influence the light cone in its form, defined areas of light and shadow can be created. In addition, there are no overlapping light fields which would result in unwanted areas with deepest shadow and partial shade in the crater area.

The control panel for lighting control provides the ability to store up to eight different lighting themes. In this way, experimental conditions can be stored and recalled at any time. Depending on the orientation of the headlamps, the sun's position for satellite missions or the position of the sun in exploration missions to the lunar south pole can be simulated.

Control center Crater (Crater Exploration ground control station)

In the crater control station, a ground station of a complex robotic mission to the moon is simulated. This ground station is mainly used in the project RIMRES. First, the control room is equipped with powerful computers, a 3D simulation allows the multi-robot scenario to be demonstrated and evaluated in computer simulations. On the other hand, there are computers for mission control. The simulation also includes a highly detailed model of the crater area from the hall, so that the performance of the simulated and real systems can be compared.

Here, the course of a mission is planned and carried out, and sent to the systems in the crater area and those of the current simulation, respectively.

control center for the crater
control center for the crater
two robots of ploy-robot-system in simulation environment
two robots of ploy-robot-system in simulation environment
© DFKI GmbH
last updated 16.09.2016
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