Kayser-Threde GmbH DEOS AUTOMATION AND ROBOTICS …

Kayser-Threde GmbH

w w w . k a y s e r – t h r e d e . c o m

Kayser-Threde GmbH

w w w . k a y s e r – t h r e d e . c o m

w e . c r e a t e . s p a c e .

DEOS AUTOMATION AND ROBOTICS PAYLOAD11th Symposium on Advanced Space Technologies in Roboticsand Automation

ESA/ESTEC, Noordwijk, / 12 – 14 April 2011

Peter Rank (KT)

Dr. Q. Mühlbauer (KT), Dr. W. Naumann (STI), K. Landzettel (DLR-RM)

Space

Industrial Applications

13 APRIL 20112 ASTRA - 2011 An OHB Technology Company

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 operationDemonstration 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).


Servicer and Client Satellite

Servicer Satellitewith Manipulator still in launch configurationLaunch mass: ca. 1025 kg incl. marginDimensions: 2380 mm * 4170 mm

(solar panels deployed)

Client SatelliteLaunch mass: ca. 820 kg incl. marginDimensions: Ф1852 mm * 1070 mm


2. FUNCTIONS OF THE AUTOMATION AND ROBOTICS PAYLOAD

Berthing of ClientClient 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


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 conditionsNumerous FDIR reactions will be definedGround Testing using the European Proximity Operation Simulation facility (EPOS)


On-orbit servicing Demonstration and De-orbiting

Two on-orbit servicing experiments:Relocation of an observation cameraExecution of a refuelling experimentAll OOS hardware on Client

De-Orbiting for controlled re-entry:client thrusters will decelerate the

rigidly coupled satellites for a controlled re-entry


3. DEOS AUTOMATION AND ROBOTICS SERVICER PAYLOAD DESIGN

DEOS Manipulator7 DoF realized using 7 joints and a gripperJoints derived from ROKVISS design

successfully flown on ISS over 5 yearsManipulator 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


A&R Payload (DEOS Manipulator, cont‘d)

Max. torque of manipulator joints: >80 NmBrakes (acting at the gear output side) active when unpoweredGear output position sensor based on Magneto Resistive Effect (MR)Redundant electronicsJoint controller and motor controller realized with DSPsDEOS 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 =>


A&R Payload (Gripper and Manipulator Camera)

GripperGripper force: 30 NTime to close or open: ~0.7 sSame motor and control electronics

as used for joints

Manipulator CameraRedundant stereo camera with targetillumination

Stereo cameraw. illumination


A&R Payload (Manipulator Camera)

Redundant stereo cameras:Field of view of 44.4° x 30.4°Resolution of 384x256 pixelsFrame 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/secStandard 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 operatorSpaceWire communication for control and image data downlinkFilter with 20nm bandwidth


A&R Payload (Target Illumination System)

Target Illumination System (TIS)Irradiance analysis shows that TIS should provide at least 10% of the sunlightLaser diode array delivers optical power of 8W (in 100 ms pulses), synchronized with camera systemWorking distance of up to 2m Cold redundant

Irradiance over distance


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 BDMa (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

BDM cone

LED pattern



Preliminary concept for Berthing and Docking Mechanism, shown with captured client (pin). Docking camera not shown. Docking and Undocking Sequence



BDM preliminary design analysisViability 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 withoutangular misalignment

for docking with =>angular misalignment


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 servicerVery 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)


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/sTM downlink: 4 Mbit/s total, ~ 3 Mbit/s image

data

Mer

ger


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 processingDuring observation phase, the IPU estimates the pose, position and motion of the clientMOCU computes a trajectory, the manipulator will execute this trajectory upon uplinkDuring 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 controlledby a human operator

Visual feedback to the operator by a three dimensional display or by a head-up displayDirect control on the Servicer by providing visual and haptic feedback to the operator


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, GermanyInstitute of Robotics and Mechatronics, DLR-RM, Oberpfaffenhofen, Germany

Special thanks to contributorsDr. Q. Mühlbauer, KTDr. W. Naumann, STIK. Landzettel, DLR-RMD. Reintsema, DLR Agency

Kayser-Threde GmbH DEOS AUTOMATION AND ROBOTICS …

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