Kayser-Threde GmbHKayser-Threde GmbH Mobile Payload Element (MPE)Concept Study of a small autonomous, and innovative Sample Fetching RoverR. Haarmann1, Q. Mühlbauer1, L. Richter1, S. Klinkner2, C. Lee2, C. Wagner2,R. Jaumann3, A. Koncz3, H. Michaelis3, J. Schwendner4, H. Hirschmüller5, A. Wedler5

(1) Kayser-Threde GmbH, Wolfratshauser Strasse 48, 81379 Munich, Germany,E-Mail: richard.haarmann@kayser-threde.com, Telefon: +49 89 724 95-347, Fax: +49 89 724 95-291(2) von Hoerner & Sulger GmbH, (3) DLR Institute of Planetary Research, (4) German Research Center for Artificial Intelligence DFKI, (5) DLR Institute of Robotics and Mechatronics

Space

Industrial Applications

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Introduction

Image courtesy to ESA

Mobile Payload Element (MPE) Small, autonomous, innovative vehicle of roughly ~15 kg Operating in the challenging environment of the

lunar south pole acquires samples of lunar soil ~100m around its lander brings them back to the spacecraft for further analysis

German national contribution to the ESA Lunar Lander Mission cancelled in fall 2012

Alternative: contribution to a Moon Exploration Program under Cooperation of ESA & ROSKOSMOS (under discussion)

Phase 0/A: April 2011 – March 2012concluded with successful PRR

Ongoing Activites Delta Phase A: October 2012 – October 2013 Locomotion Subsystem Avionics Close-up Imager Sample Transfer Mechanism Autonomy Payload Experiment & Illumination Prediction Image courtesy to Roskosmos

Reference Scenario & Model Payload

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Reference Scenario Realistic background for

subsystem trade-offs Environmental conditions Operation Communication Power,…

MPE Model Payload and Sampling Acquisition of regolith samples illuminated and locally shaded terrain surface, subsurface underneath large boulders

Documentation of the samples In-situ characterization of the sample

material A Camera Payload: Stereo camera with LED-illumination

A Scientific Payload: Mole sampler Close-Up Imager Philae ROLIS Close-Up Imager

MOLE Sampling Device

Stereo Camera

4

MPE OverviewActive Chassis adaption of each wheel to the surface alignment of solar generators

and instrumentsPower Supply System Solar generators: 25W Secondary battery: 160Wh

Active Thermal Control System Operation in shaded regions: >2h Survivable darkness periods: >13h

Communication UHF-band (up/down): 9.6 kbit/s S-band (down): 512 kbit/s

Onboard Computer LEON3FT GR712RC

Sensor Package Stereo Camera LED flash lighting 2 axes inclinometer Wheel and body encoders

Operational Modes Tele-operated mode Autonomous mode

Mass Budget SummaryMPE Concept Phase A

Total Massincl. Margin [kg]

MPE (Rover + Payloads) 15,777

Rover (w/o Payload) 13,525

Camera Payload 0,305

Scientific Payload 1,948

MPE Overview

5

900m

m

990mm

823m

m

740m

m

700mm660mm

541mm

493mm

493mm

303mmMole Sampler

Close-upImager

Compatibility to the Russian Moon Exploration Programm

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Current Situation ESA Lunar Lander Mission Stopped in fall 2012

Lunar Resource/Chandrayaan-2 Terminated in January 2013

ESA and Roscosmos currently discuss acorporate lunar exploration program

A future program will probably comprisea rover mission, similar to Lunar Landeror Lunar Resource

Both missions were very similar: Operation on lunar south pole area in highly illuminated areas Collection of soil samples Rover weight: ~10kg - ~15 kg Mission duration: 6-9 months - 12 monthsConclusion: MPE it is highly suitable for an upcoming ESA/Russian Mission If usage of RTG‘s and RHU‘s are possible (like Lunar Resource) Survival capabilities of darkness periods could be increased Image courtesy

to Roskosmos

Image courtesy to Roskosmos

Actuator Design

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ILM 38 Motor Units Actuator design is based on permanent magnet

synchronous motors, developed at DLR RMC Combined with low backlash Harmonic Drive gears Derived from ROCKVISS actuation unit Same technology was further developed for

DexHand and MASCOT

Advantages of those ILM actuators Well suited for high dynamic tasks High efficiency High torque capacity Low number of mechanical components

Trade-Offs led to Incorporation of PTFE sealing combined with

labyrinth Potentiometer as absolute position sensor

(position controlled actuators only)

Combined with low backlash Harmonic Drive gears

Same technology was further developed for

Wheel Design

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Requirements Provide ground interaction Withstand static & dynamic loads Withstand temperature cyclesParameters MPE nominal velocity: 5.4 mm/s (tele-ops.) Terrain: lunar Regolith with varying degree of

compactness Minimum diameter: 250mm accommodation of driving and steering actuator within the wheel

Approach Several concepts were established and

evaluated 3 wheel-options were designed and traded Wheel properties and strength were

determinedWheel Design Diameter: 250mm Width: 60mm

can be reduced down to 40mm 25 Grousers

Mass:Al-Version: 267gTi-Version: 160g

Integrated Avionic Design

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Design Drivers Minimal volume and mass. Efficient use of solar & battery power minimal energy wastage on unused functions.

Prevention of fault propagation in-built fault tolerance whenever possible

Extreme non-operational cold environmentSystem Layout Power subsystem Rover subsystem

Communications Onboard computer

Actuator subsytem Payload Subsystem

Payload power control Interfaces

Backplane Ground bar Starpoint

Autonomy Payload Experiment

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Optional payload on MPE Additional pan/tilt unit (see A. Wedler, ASTRA 2013, Paper# 2811409 )

Additional FPGA(Virtex 4QV (XQR4VFX60) or Virtex 5)

Flash module with the bitstream toprogram the FPGA

RAM module with storage size of 128 MB Power and communication driver electronic

Can be completely switched on/off Enhances the MPEs autonomy functions Advanced dense stereo matching methods can be

implemented (e.g. SGM) Allows stereo rectification Further image compression allows 1.5 Hz image

stream down to Earth Allows full autonomous driving Increases accuracy & robustness Increases the MPE speed

Illumination Prediction

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Challenging Illumination Conditions Max. Sun inclination:

3° over the horizon Complex and dynamic illumination

situation at ground level Illumination condition is highly

dependent on the local shape of the terrain

ConceptCombination of DEM and horizon models DEM centered at the lander location Generated by LRO Data before landing Generated by lander after landing Updated by stereo images of MPE

DEM has size of MPE operational area Horizon rings provide max. terrain elevation for

angular subsection Angular resolution independent from distance Multiple rings to compensate for parallax errors

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Sample TransferEndeffector on lander‘s robotic arm Completely passive device, actuated via arm force

Opening by pressing it on ground Closing via springs

Protects sample from direct solar illumination Ability to take surface samples Ability to receive samples from mole Ability to transfer mole/surface samples to

instrument ports Protection against clogged material / cross

contamination (via Piezo) Further concepts will be assessedand detailed

Completely passive device, actuated via arm force

Mole

Close-up Imager

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Rear CameraClose-UpImager

Mirror Narrow Angle Optics

Detector

Contradictory requirements lead to a two-lens/two detector design approach

Narrow-angle multispectral Close-up Imager (CUI) Sample characterization Focusing towards the mole LED Illumination FoV: 17,85° Focal length: ~45mm High resolution: 33μm/pixel

(1920x1080 CMOS)Wide-angle Rear Camera Tele-operated backward driving Wide-Angel rear view FoV: 89° Low resolution: ~512x 512 pixel

(to keep data rate low)

Total CUI mass: 0.73kg (incl. margin)Power: 5W (multispectral imaging)

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Summary & Outlook

MPE is the first sample fetching rover worldwide in the 15kg-class: dedicated mobile sampling device

Provides access to uncontaminated scientific interesting objects in an area ~100m around the Lunar Lander Controlled sample volume Regolith samples from surface and subsurface Regolith samples from illuminated and locally

shadowed terrain as well as from below boulders and blocks

MPE is versatile and can be incorporated in several missions

Innovative rover for technology demonstration as well as for the A&R community

MPE has a high public outreach potential

The Mars Pathfinder microrover Sojourner observed by its lander

Image courtesy to NASA

The Mobile Payload Element observed by its lander

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MPE Summary & Outlook

The MPE study had a successful PRR Review and Final Presentation at DLR Space Management in March 2012

The current MPE Delta Phase A started in October 2012 with focus on critical technologies and breadboard preparation

The MPE Team envisages to continue with a breadboard and testing phase, beginning in late 2013

The Mobile Payload Element is an excellent opportunity for the demonstration of European competences in space robotics

Thank You

Richard HaarmannRichard.Haarmann@Kayser-Threde.com

Aknowledgements:The MPE study was funded under DLR contracts 50JR1006 and 50JR1212

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