DEOS AUTOMATION AND ROBOTICS PAYLOAD

Transcription

1 w e. c r e a t e. s p a c e. Kayser-Threde GmbH Space Industrial Applications DEOS AUTOMATION AND ROBOTICS PAYLOAD 11th Symposium on Advanced Space Technologies in Robotics and Automation ESA/ESTEC, Noordwijk, / April 2011 Peter Rank (KT) Dr. Q. Mühlbauer (KT), Dr. W. Naumann (STI), K. Landzettel (DLR-RM) w w w. k a y s e r t h r e d e. c o m

2 1. INTRODUCTION DEOS: Deutsche Orbitale Servicing Mission DEOS primary mission goals: Capturing of a tumbling and non-cooperative satellite by a manipulator and Controlled re-entry of the rigidly coupled satellites within a given re-entry corridor DEOS Secondary mission goals: Demonstration of the capturing procedure applying different methods with a free floating servicer in tele-presence operation and in autonomous operation Demonstration of the on-orbit servicing capabilities e.g. in-orbit replacement of a component and capturing of an attitude controlled satellite. Conduction of the tasks under different environmental conditions (e.g. illumination conditions) and at different orbit height (starting from 600 km down to 450km/400km) APRIL 2011 ASTRA An OHB Technology Company

3 Servicer and Client Satellite Client Satellite Launch mass: ca. 820 kg incl. margin Dimensions: Ф1852 mm * 1070 mm Servicer Satellite with Manipulator still in launch configuration Launch mass: ca kg incl. margin Dimensions: 2380 mm * 4170 mm (solar panels deployed) 3 13 APRIL 2011 ASTRA An OHB Technology Company

4 2. FUNCTIONS OF THE AUTOMATION AND ROBOTICS PAYLOAD Berthing of Client Client satellite AOCS supports three modes: 3-axis stabilized, spinning up to 4 /s and tumbling (spinning and superposition of a nutation angle). Servicer distance to the client satellite maintained in the range between 1 m and approx. 2.5 m within a spherical tolerance range of 7 cm Observation time of about 2 minutes to determine the client motion and to predict the movement profile (Payload Control System software on ground) Manipulator motion planner software running online in the PCS calculates the motion profile and prepares data for uplink to the robot in space Computation of the relative position by analysis of manipulator stereo camera data and delivers correction commands (visual servoing) Correction data considering haptic data from joints prepare capturing start of manip. activity just before capturing final grappling 4 13 APRIL 2011 ASTRA An OHB Technology Company

5 Berthing of Client Loads on the end-effector during capturing Berthing in progress Servicer attitude during stabilization phase Servicer AOCS actuators deactivated during berthing and stabilization Supervised autonomy mode: complementary on-board functions and on-ground functions are executed without ground operator interaction under normal conditions Numerous FDIR reactions will be defined Ground Testing using the European Proximity Operation Simulation facility (EPOS) 5 13 APRIL 2011 ASTRA An OHB Technology Company

6 On-orbit servicing Demonstration and De-orbiting Two on-orbit servicing experiments: Relocation of an observation camera Execution of a refuelling experiment All OOS hardware on Client De-Orbiting for controlled re-entry: client thrusters will decelerate the rigidly coupled satellites for a controlled re-entry 6 13 APRIL 2011 ASTRA An OHB Technology Company

7 3. DEOS AUTOMATION AND ROBOTICS SERVICER PAYLOAD DESIGN DEOS Manipulator 7 DoF realized using 7 joints and a gripper Joints derived from ROKVISS design successfully flown on ISS over 5 years Manipulator arm kinematics has to provide max reach and dexterity for capturing of the client independent from the client s main spinning axis The arm will be kinematically redundant to avoid joint-singularities during capturing Length 3232 mm 7 13 APRIL 2011 ASTRA An OHB Technology Company

8 A&R Payload (DEOS Manipulator, cont d) Max. torque of manipulator joints: >80 Nm Brakes (acting at the gear output side) active when unpowered Gear output position sensor based on Magneto Resistive Effect (MR) Redundant electronics Joint controller and motor controller realized with DSPs DEOS control loop frequency reduced from 500 Hz (ROKVISS) to 200 Hz Instead of SERCOS bus hardware used in ROKVISS, EtherCAT technology will be implemented in DEOS providing significant gain in functional reliability/redundancy => EtherCAT Ring => 8 13 APRIL 2011 ASTRA An OHB Technology Company

9 A&R Payload (Gripper and Manipulator Camera) Gripper Gripper force: 30 N Time to close or open: ~0.7 s Same motor and control electronics as used for joints Manipulator Camera Redundant stereo camera with target illumination Stereo camera w. illumination 9 13 APRIL 2011 ASTRA An OHB Technology Company

10 A&R Payload (Manipulator Camera) Redundant stereo cameras: Field of view of 44.4 x 30.4 Resolution of 384x256 pixels Frame rate of up to 10Hz Radiation hard STAR1000 sensor (1024*1024 pixels) Including close range stereo camera images, a total of up to four images with different frame rates and different resolutions have to be transmitted simultaneously: ~ 3Mbit/sec Standard JPEG compression (e.g. for monitoring or telepresence) Custom compression algorithm with a compression rate of 5 to 20 (edge detection algorithm followed by a lossless compression of either the edge image or a sparse image) Tilted around the horizontal axis for visibility of the gripper for the human operator SpaceWire communication for control and image data downlink Filter with 20nm bandwidth APRIL 2011 ASTRA An OHB Technology Company

11 A&R Payload (Target Illumination System) Target Illumination System (TIS) Irradiance analysis shows that TIS should provide at least 10% of the sunlight Laser diode array delivers optical power of 8W (in 100 ms pulses), synchronized with camera system Working distance of up to 2m Cold redundant Irradiance over distance APRIL 2011 ASTRA An OHB Technology Company

12 A&R Payload (Berthing and Docking Subsystem ) Berthing and Docking Subsystem overview: on the Servicer satellite: Berthing and Docking Mechanism (BDM) the Docking Camera attached to the lower end of the BDM on the Client satellite: a pin mating to the BDM a (switchable) LED pattern encircling the pin (the Docking Camera as sensor system in combination with the light pattern provides relative position and angular misalignment information for the Servicer AOCS during final approach) pin LED pattern BDM cone APRIL 2011 ASTRA An OHB Technology Company

13 A&R Payload (Berthing and Docking Subsystem ) Preliminary concept for Berthing and Docking Mechanism, shown with captured client (pin). Docking camera not shown. Docking and Undocking Sequence APRIL 2011 ASTRA An OHB Technology Company

14 A&R Payload (Berthing and Docking Subsystem ) BDM preliminary design analysis Viability of BDM concept for Servicer to Client docking has been demonstrated by contact dynamic simulations: successful docking supported at 0 to ± 5 angular and 0mm to 75mm lateral misalignment Phase B considers potential concept improvements reducing the complexity and susceptibility w.r.t. single point failures Contact dynamic simulations <= for docking without angular misalignment for docking with => angular misalignment APRIL 2011 ASTRA An OHB Technology Company

15 A&R Payload (ICU) Instrument Control Unit (ICU) Master CPU board responsible for payload control, monitoring of all A&R payload subsystems and communication with the servicer OBC (status and housekeeping data for supervision, telemetry downlink uplink command reception and execution) Slave CPU board with extremely high computing power (requirement: 1100 MIPS incl. margin) and floating point operation for control of the manipulator via EtherCAT SpaceWire router is used for direct downlink of camera data via the servicer Very low latency and jitter is allowed for the entire communication loop VxWorks operating system for use of MARCO (modular software framework for control of complex real-time systems, developed by DLR-RM) APRIL 2011 ASTRA An OHB Technology Company

16 4. PAYLOAD CONTROL SYSTEM ON GROUND A&R Payload Control System (PCS): Part of the Flight Operations System in the Mission Control Centre (MCC), receiving telemetry frames (TM) and responding with telecommands (TC) Payload Operation Control Unit (POCU) connected to a Merger of the Ground Data System of the MCC, unpacks the telemetry frames and distributes them to the other PCS sub-units The images are uncompressed and displayed for monitoring in the Video Control Unit (VCU) The on-ground part of the manipulator control is conducted in the Manipulator Operation Control Unit (MOCU) TC uplink: max 256 kbit/s TM downlink: 4 Mbit/s total, ~ 3 Mbit/s image data Merger APRIL 2011 ASTRA An OHB Technology Company

17 A&R Payload Control System (PCS) DEOS Autonomous mode: MOCU is controlled by the Image Processing Unit (IPU) decompressed images as input for the actual image processing During observation phase, the IPU estimates the pose, position and motion of the client MOCU computes a trajectory, the manipulator will execute this trajectory upon uplink During trajectory execution, the IPU estimates the position and orientation of the handle on the client. MOCU will update the trajectory in real-time DEOS Tele-presence mode: a robot arm on ground serves as a haptic input device, which is controlled by a human operator Visual feedback to the operator by a three dimensional display or by a head-up display Direct control on the Servicer by providing visual and haptic feedback to the operator APRIL 2011 ASTRA An OHB Technology Company

18 5. ACKNOWLEDGEMENTS The Phase B study for the DEOS Automation and Robotics payload is performed on behalf of the Space Agency of the German Aerospace Center DLR funded by the Federal Ministry of Economy and Technology (Förderkennzeichen 50 RA 0923). Partners in the Automation & Robotics Payload Team lead by Kayser-Threde: SpaceTech GmbH, Immenstaad, Germany Institute of Robotics and Mechatronics, DLR-RM, Oberpfaffenhofen, Germany Special thanks to contributors Dr. Q. Mühlbauer, KT Dr. W. Naumann, STI K. Landzettel, DLR-RM D. Reintsema, DLR Agency APRIL 2011 ASTRA An OHB Technology Company