Topic Robotics: On-Orbit Servicing (OOS)
Objectives
Debris in LEO
1. Active Debris Removal
Debris in LEO
DEOS MISSION
- Inoperative Satellites
- Upper Stages of Rockets
- Collision/Explosion Fragments
Methods
Semi-Autonomy
System overview
Target as seen by Servicer
Tumbling
Target
Physical interaction
after grasping
Parameter
Identification
Motion
Planning
Off-line
Robot
Control
Servicer-Robot
On-line
Telepresence
on ground
-
ORU Exchange
Repair
Deorbiting
Life Extension
Refueling
Possible targets: ENVISAT, Zenit-2
Target Motion Estimation and Prediction:
- Grasping a non-cooperative debris object
(unknown tumbling rate, complex geometry)
- Generating feasible trajectories in a useful time
(highly nonlinear optimization problem)
 Telepresence (see dedicated poster)
Target
Motion
Prediction
2. On-Orbit Servicing
on board, on-line
1. Estimation based on automatic
detection and tracking of local
features or known geometric model
2. Long-term prediction (100 seconds)
System Parameter Identification:
- Rigid body identification Servicer/Target
- Flexible bodies (e.g., solar panels)
- Fuel sloshing
- Dynamic model update
Motion Planning:
- Free-floating dynamics model
- Satisfying motion constraints
(e.g., collision avoidance)
- Real-time reference trajectories with look-up table
Robot Control:
- Free-floating robot dynamics
- Impedance control
- Tracking of reference trajectory
- Visual servo input
Simulation
EPOS
VR - OOS
- Simulation of Rendezvous
and Docking (RvD)
maneuvers (25-0 m)
- Realistic illumination
conditions
- Simulation of impact
dynamics during contact
F
x
Haptic Device
Interactive OOS VR
DEOS-Simulator
- Testing platform for close
proximity operations (e.g.
grasping and stabilization)
- Hardware-in-the-loop
with free-floating
dynamics emulation
Haptic Rendering
- Manipulation of an OOS
scenario in the VR using
haptic feedback
- Haptic rendering
algorithm able to
compute forces between
complex objects in 1 ms
- Voxelized distance fields,
as well as point and
sphere hierarchies used
as data structures