OPS G Forum Operational Requirements for Robotic Exploration 24.03.2006

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2006-03-24 1

RB / 2006-03-24 1

AURORA AURORA -- Operational RequirementsOperational Requirementsfor Robotic Explorationfor Robotic Exploration

Reinhold Bertrand

OPS-GTM

OPS-G Forum24 March 2006

RB / 2006-03-24 ESOC OPS-G Forum

Op. Requirements for Robotic ExplorationOp. Requirements for Robotic Exploration

2

OutlineOutline

1. Context and Motivation:

2. ExoMars: Typical Mission and System Requirements

3. Rover Navigation & Control

4. Operational Requirements

5. Conclusions

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Aurora - ESA’s Space Exploration Programme

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OPS-G Forum, 2006-03-24



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Exploration Performance DriversExploration Performance Drivers

Perception capabilities:– Recognise / understand environment and targets– “see”, process, analyse targets / samples

Mobility capabilities:– Reach targets– Access, touch, grasp, collect samples

(digging, drilling, etc.)

Operational capabilities:– Autonomy (signal delays, hard real-time requirements,

mission duration constraints, ground interaction needs)– Unstructured / unknown environment:

autonomous decision making, unexpected situations, contingencies

– Adaptability / flexibility of operations– Exploration System Approach (P/L↔Rover)

Robotic SystemsContext &Motivation

1.

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OutlineOutline





5. Conclusions



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What is ExoMarsWhat is ExoMars??

Search for traces of past and present life on Mars:

– Where does life come from– How/where did it evolve– Is Earth a normal case or

a singularity

Deploy on the Martian surface a Rover carrying a suitable analytical P/L (Pasteur)

ExoMars

2.

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ExoMars ExoMars ObjectivesObjectives

Scientific Objectives:– To search for traces of past and present life on Mars– characterise, in the shallow subsurface, vertical

distribution profiles for water and geochemical composition

– measure planetary geophysics parameters – study the surface environment and identify hazards to

human missions

Technology Objectives– Land large payloads on Mars– Demonstrate high surface mobility

and subsurface access– Prepare technologies for MSR

ExoMars

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Looking for signs Looking for signs of life:of life:

Life is cells:– Need water– Requires sugars (energy source and

backbone for nucleic acids)– Cell menbranes are built with phospholipids

Life has Homochirality– 2 mirror forms of biomolecules (enantiomers)– Life uses only one enantiomer, e.g.

Left handed (L) amino acidsRight handed (R) sugars

ExoMars

2.

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What to search for?What to search for?

Extant Life: Biomarkers, such as:

Amino acids Nucleotides Sugars Phospholipids Pigments

• • •

Extinct Life:– Organic residues of biological origin;

(chemical, chiral, spectroscopic, and isotopic information)– Images of groups of fossil organisms and their structure;

(morphological evidence)– Geochemical and mineralogical effects of biology on the environment.

(second order)

ExoMars

2.



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Where to search?Where to search?

Liquid water is presently unstable on the Martian surface

The solar UV dose is harmful to unprotected life and organic compounds.

the search for extant life will focus on the subsurface.

warm spots with evidence of water deposits at accessible depths, as identified from remote sensing satellites, i.e. Mars Express & MRO.

For extinct life, the search strategy relies on looking for well-preserved biosignatures, i.e. encased in the geological record as microfossils.

the search for extinct life will also focus on the subsurface.

On sites occupied by bodies of water over extended time periods:– Sedimentary deposits in ancient lake beds,– Remains of hydrothermal systems;– Outflow regions of past water channel systems.

ExoMars

2.

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ExoMars ExoMars Landing SitesLanding Sites

–15º

+ 45º

ExoMars Latitude Landing BandExoMars

2.



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How How to look to look for signs for signs of life: PASTEURof life: PASTEUR

Panoramic Stereo Camera

Infrared Spectrometer

Ground-Penetrating Radar

Close-up Imager

Moessbauer Spectrometer

Combined Laser Plasma / Raman Spectrometer

Microscope

XRD

Life Marker Chip

Mars Organic Detector (MOD/MOI)

Gas Chromatograph / Mass Spectrometer

Drilling system (2 m)

Sample preparation and handling subsystem

ExoMars

2.

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ExoMars ExoMars Payload: Payload: PasteurPasteur

Ana

lytic

al L

ab.

Con

tact

Su

iteR

emot

e

ORGANICS/LIFE

MOD/MOIGC-MSLife Marker Chip

ENVIRONMENTDust & H2OIonising Rad.UV Rad.P, T, Wind

Accommodated in GEP

CONTEXTPanCamIR Spectr.GPRNeutron Scatt.Close-up ImagerMössbauerAPXSRaman & LIBSMicroscope IRXRD

SUPPORT INSTRUMENTS

Drill System(2-m depth & surface)

incl. Borehole IR

Manipulator Arm

Sample Preparation & Distribution System

ExoMars

2.



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Pasteur: Drill SystemPasteur: Drill System

ExoMars

2.

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Pasteur: Analytical LaboratoryPasteur: Analytical Laboratory

MicroscopeRaman / LIBS

SampleDestructiveanalysis

Non-destructiveanalysis

GC-MS

LifeMarkerChip

Dust

MOD

Fluorescamine

CE

RockCrusher

AnalyteExtraction

Extraction &CruscibleOxidants

XRD

MOD

Drill System

Nominal mission:

10 surface +20 subsurfacesamples

ExoMars

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ExoMarsExoMars TopTop--Level Level RequirementsRequirements

Transport, deploy and operate the Pasteur payload, in particular:– Collect material samples at the surface and from the sub-surface (2 m)– Store, process, and analyse samples „in-situ“

Implement at least 10 experiment cycles, composed of:– Locomotion to next sampling site (500-2000 m)– Sample collection (drilling) and processing– Data processing and transmission

One command cycle per day (Sol) only

Compatible with Environmental Conditions/Requirements for– Launch, interplanetary transfer, re-entry, landing– Mars environment (10 ... 45° latitude North or South),

VL2 landing site conditions– Planetary Protection

ExoMars

2.

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ExoMars ExoMars Rover Mission ParametersRover Mission ParametersNominal mission: 180 sols;Nominal science: 10 Experiment Cycles + 2 Vertical Surveys;Extended mission: 10 additional Experiment Cycles;Experiment Cycle length: 6 – 18 solsSandy slopes of up to: 25 deg;

ExoMars

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Typical Rover DesignTypical Rover Design

Total mass (including 48 kg P/L) 253 kg

Body Dimensions (l x w x h) 1500 x 630 x 580 mm

Wheels Ø300 x 100 mm

Track distance (c-c) 1070 mm

Ground clearance 310 mm

Solar Array InGa/GaAs/Ge, 1.5 m2

Batteries Li-Ion, 1500 Wh

Thermal RHU, 2 x 15 W, loop heat pipes

Data: 680 Mbits per exp. cycle

Communications: X-band DTE, UHF to orbiter relay

ExoMars

2.

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Typical Rover Design: LocomotionTypical Rover Design: Locomotion

Effective locomotion speed: 100 m/sol (72 m/h nominal)

Max. slope climbing: 25 Deg.

Tip-over limit 40 Deg.

Max. obstacle height: 300 mm

ExoMars

2.



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ExoMars ExoMars vs. MERvs. MERMars Exploration Rovers (2004)

– Rover 185 kg– P/L 14.8 kg– Mobility: 10-40 m/d; < 1 km total– Instruments: distributed, miniaturised– Regional exploration

ExoMars (projected), 2011– Rover 254 kg– 48 kg complex P/L facility– Mobility: ~100 m/d;

5 - 20 km total– Regional exploration– Multiple drilling/sampling,

sub-surface sampling

ExoMars

2.

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OutlineOutline





5. Conclusions



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How to navigate through an unknown How to navigate through an unknown environment ???environment ???

ModellingDigital Terrain Model

Decisionpath, trajectories

Perceptione.g. Stereo Vision

Actionlocomotion monitoring & control

Localisationposition, orientation

Rover N&C

3.

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Basic Basic Functions for Functions for Navigation & Navigation & ControlControl

Perception: Data Acquisition (surrounding environment, stereo vision)

Environmental Modeling: Digital Terrain Model (DTM)

Localisation: position and orientation in the DTM

Decision: path / trajectory planning, based onDTM, obstacles, rover state, current objective, resource/risk considerations

Action: locomotion monitoring and control

Rover N&C

3.



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N&C Example 1: SojournerN&C Example 1: Sojourner

“classical” approach: Direct Control (all planning on ground)

Earth MarsPerception (stereo vision)DTM on GroundlocalisationDecision pre-planned sequenceAction

Minimised risk, max. control

Time consuming

Limited performancein rough terrain

Not usable for “long” trajectories

Rover N&C

3.

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N&C Example 2: MERN&C Example 2: MER

Largely Direct Control

Autonomous local navigation: AutoNav “Obstacle Avoidance Scheme”

Earth MarsPerception (stereo vision)DTMlocalisationDecision: elementary trajectory evaluationAction: Trajectory execution (short distance)

Rover N&C

3.



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MER Operations: Lessons learnedMER Operations: Lessons learned

Localisation is critical in some situations (ground slippage)

Better locomotion abilities required (slip detection)

Higher autonomy required to traverse “cluttered” areas(reach a given target through some sort of itinerary)

Several ground interactions required to place instruments

End of autonomous motions may leave rover in bad attitude(w.r.t. antenna, solar panel)

Rover N&C

3.

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ExoMarsExoMars Navigation & Navigation & Control RequirementsControl Requirements

Enable autonomous operations for one sol (one comms session per sol)

Traverse > 100 m per sol

Reach a target location– at a distance up to 100m with an accuracy of 10m– distance up to 20m with an accuracy of 0.5m– 2m with an accuracy of 0.05m

Path planning and execution functions:– Autonomously advance along a sequence of way points

pre-planned on Ground– Autonomous path planning (goal tracking, obstacle avoidance,

minimisation of risk and resource consumption)

Autonomously classify and negotiate obstacles:– Ignore / overcome / avoid / stop

Rover N&C

3.



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N&C Key TradeN&C Key Trade--Offs Offs

Degree of autonomy on the planetary surface

Distribution of functions, models, processing capabilities decision authority.

Efficiency / feasiblility versus safety, reliability, risk

Control Autonomy / role of human operator to be scaled according to the control task:

– Type of environment– Length of trajectories– Motions w.r.t. a target

Rover N&C

3.

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ExoMars ExoMars Navigation & Control ApproachNavigation & Control Approach

Four Control Modes:

Long traverses, difficult terrain

Define itinerary to follow, specification of goal and sub-goals

Long Range Mode

Trajectory defined w.r.t. a locomotion targetTarget reaching mode

For easy traverses beyond the “3D view” of the operators

Local autonomous navigation (MER - AutoNav)

Safeguarded Mode

For short motions, easy traverses, difficult situations

No on-board decisions, trajectories planned on ground

Direct Control

Operator selects and configures a suitable operational mode

Rover N&C

3.



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ExoMarsExoMars Navigation & Control Approach (2)Navigation & Control Approach (2)

4 operational modes reflecting different levels of autonomy / direct operator control

Perception through stereo vision

Localisation through multiple sensors:– 3D Odometry (wheel encoders, steering angles, chassis angular config.)– Inertial navigation (gyrometer, IMU)– Visual odometry (motion tracking in images)– Sun Sensor

Decision:– Local DTM with traversability assessment per cell– Merging into a global navigation map, maintained over long ranges– Target tracking in visual model / DTM– Definition of sub-goals (“path planner”) and associated perception tasks– Definition of trajectories (“trajectory planner”)

Rover N&C

3.

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ExoMarsExoMars Navigation & Control Approach (3)Navigation & Control Approach (3)

Action– Several nested loops

individual wheel controlrover body speed controlnavigation control

– Wheel walking control– Locomotion monitoring

Position trackingAttitude / chassis internal anglesWheel slippageLocalisation algorithm monitoring

Rover N&C

3.



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OutlineOutline





5. Conclusions

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Rover Operations ImplicationsRover Operations Implications

Three players at least:– Overall mission control– Rover navigation & control– Payload control

Strong interrelationships

Overall exploration performance is“end to end”: Mission – Rover – Pasteur

Strict separation MOC-SOCnot suitable

Scientific Users interface with rover and P/L control

Regional distribution of control centres is critical,for rover and payload control a separation is unsuitable

Mission Control

Rover Control Payload Control

Ops. Requ.

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Operations Centres Requirements: RoverOperations Centres Requirements: Rover

Methods and tools to cover all operational modesfrom direct control to long range mode

Specifics (besides “usual” M&C):– DTM (local, regional, global),

to be updated constantly– 3D Monitoring /

Visualisation techniques– All related processing capabilities

(imaging, sensor filtering / fusion)– Path and trajectory planners,

optimisation tools– Simulators:

S/WRover test benches including H/W models

– Needs link to P/L control for both, planning and verification– Public outreach issues

Ops. Requ.

4.

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Ground Support ToolsGround Support Tools

Global high level mission planning tools(time / ressource constraints, overall rover activities)

Functional navigation tools– 3D environment modeling– Complex trajectory planner– Rover simulator

Debriefing tools– Localisation (w.r.t. skyline, orbiter map, panoramas)

Situation analysis

Rough terrain traj. planner

Ops. Requ.

4.



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Operations Centres Requirements: P/LOperations Centres Requirements: P/L

traverse wac gpr traverse wac gpr

traverse wac gpr hrc drill lowmagmic

spds

gc-ms moi

raman libs

lmc

AUTOMATIC ANALYSIS SEQUENCE

himagmic

spds

raman libs

DETAILED ANALYSIS SEQUENCE

earth

earth

earth earth

earth

earth

mod

environmental / hazard sensors



gc-ms moi lmcmod

Ops. Requ.

4.

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Operations Centres Requirements: P/LOperations Centres Requirements: P/L

Pasteur contains classical science instruments as well as robotic systems (drill, robotic arm, PanCam, SPDS)

Strongly depends / interacts with rover vehicle as carrying platform

Needs DTM in high resolution (mm range)

Similar planning / verification tools for robotic components

Ops. Requ.

4.



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ConclusionsConclusions

Operation of a robotic exploration mission on planetary surfaces (ExoMars) is characterised by

– Unknown and unstructured environment– Control needs under hard real time conditions– Complex rover and P/L operations– Restricted communications access (frequency, delays, as usual)

“classical” direct control schemes and automation of operations can not do the job

Change in culture: Operational Autonomy“let the child walk on its own”

A third block of operational functions protrudes:Mission – Rover Control – Payload Control

Operations concept must be truly interdisciplinary,location/distribution of control centres is critical for performance

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Prepare the ground for new insights Prepare the ground for new insights ......

The End



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AcknowledgmentsAcknowledgments

Many Thanks for viewgraph and video contributions as well as for reviewing support to

Michael McKay, OPS-OSCJorge Vago, HME-GAP

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Contributions to Contributions to ExoMarsExoMars (%)(%)

Total Subscription 109.79% = 650.8 MEUROs

16.02

14.51

40

7

5.47

17.041.018.74

FranceGermanyItalySpainSwitzerlandUnited KingdomCanadaOthers < 3%